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000
FXUS66 KOTX 172356
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
356 PM PST WED DEC 17 2014

.SYNOPSIS...
A more active weather pattern will continue through the end of the
week with periods of light snow in the mountains...and rain or
snow in the valleys. Lower elevations from Interstate 90 south
will see mainly rain...while areas in the Cascades and near the
Canadian border will remain mainly snow. A much stronger weather
system over the weekend will usher in warmer temperatures with
sharply rising snow levels...as well as the potential for windy
conditions.

&&

.DISCUSSION...

Tonight and Tomorrow...A number of small weak disturbances running
across Eastern Washington and Northern Idaho through tonight and
tomorrow. They are very difficult to pick out in some of the
models as there is too much clutter in the flow associated with
the weakening baroclinic band upon where these disturbances are
located near that is currently passing through the area. They
haven`t been showing up too well in the radar either as they have
been far enough away for most of the day for the base elevation
beam to get a return on as well. Best bet to find these features
has been the IR satellite imagery on a fast rock and picking out
the small scale rotation and cloud top cooling. One such feature
is moving northeast this afternoon and is causing precipitation
just east of Moses Lake up to Omak and some points to the north
and east. A second feature, appearing to almost be a southern part
of the splitting/weakening baroclinic band has brought light rain
to Lewiston. All of these disturbances translate to the Northeast
and East at varying times tonight and tomorrow and as such the
pops and QPF show a general favoring of locations to the North and
East (including locations near Spokane down to Pullman) to receive
some precipitation but as expected the amounts are not too
significant...still it doesn`t take too much liquid to pool on
pavement that in turn cools overnight to allow for slick
conditions in spots similar to what occurred this morning.
/Pelatti

Thursday night through Sunday...An active weather pattern is
expected especially over the weekend with two systems to impacts
the Inland Northwest during this forecast period.

Thursday night/Friday: A large upper low seen on Infrared
Satellite Imagery in the Gulf of Alaska will drop southeast
sending a cold front across the area. The timing of the front
tracks into Central Washington Thursday night during the overnight
hours...reaching Eastern Washington and North Idaho Friday
morning. A north-south oriented jet parallel to the front and
southerly low/mid level flow will minimize downslope flow with all
areas likely to receive some precipitation. Inspection of model
soundings suggest this to be a mainly valley rain or rain/snow
mix...with snow in the mountains. 850mb winds backing to the south
will aid in bring up warmer air from the south. However a wedge of
cooler air trapped along the East Slopes of the Cascades will
result in lower snow levels over North Central Washington with the
potential for 2-3 inches of snow accumulation above 1000-1500
feet. This includes the Methow Valley, Plain, Waterville Plateau,
higher portions of Omak, and Republic. The Wenatchee area and
lower portions of the Okanogan and Columbia River valleys are
expected to see mainly a rain/snow mix or wet non-accumulating
snow. The mountains will generally see 2-5 inches of snow with the
Cascades seeing the highest amounts.

Saturday through Sunday...A much stronger system is expected this
weekend bringing a wide variety of expected weather. The models
continue to show an atmospheric river as a subtropical moisture
fetch becomes aimed at the area. The leading edge of this moisture
will enter on Saturday in the form of a warm front. Strong
isentropic lift will result in the development of widespread
rain and snow. 850mb winds backing to the south-southeast will
favor upslope flow into the northern mountains, with cooler air
remaining banked up into the Cascades, Okanogan Valley, and
Okanogan Highlands. Models suggest the potential for moderate to
locally heavy snow accumulations in these areas along and ahead of
the warm front before snow levels rise from south to north
Saturday night into Sunday morning. Snow levels will be fast to
rise from Interstate 90 south with precip expected to fall as
mainly valley rain and mountain snow. The valleys north of Spokane
such as Colville, Metaline Falls, Priest Lake, and Bonners Ferry
may start off as snow on Saturday with light accumulations...before
changing to rain Saturday night. As the warmer air aloft pokes
into the Cascades Saturday night...the valleys will likely have a
hard time mixing out with freezing rain possible especially south
of Lake Chelan in places like Plain and Leavenworth.

On Sunday the atmospheric river shifts south near the
Washington/Oregon border with strong westerly flow over the area.
This will lead to a strong rain shadow east of the Cascades with
precipitation likely confined mainly to the Cascade crest, Idaho
Panhandle, and southeast Washington. 850mb winds of 25-35 kts and
possible sun breaks across the Columbia Basin...and 850mb temps of
3-6C could lead to very mild temperatures along with breezy to
windy conditions. For now went a bit above MOS guidance which
usually does not go warm enough in these situations. JW

Sunday Nt through Christmas Eve: Following the passage of the windy
and wet short-wave trough that will move through broad upper
ridging Sunday Nt, what`s left of a stalled cold frontal boundary
will remain over Nrn Oregon and extreme Srn Wa Tues and keep the
threat of pcpn in the fcst for the Lewiston area as well as the Camas
Prairie. Where this front stalls will be critical as far as the
Christmas Eve fcst, because it is this boundary that will combine
with a significant short-wave trough and vort max moving into the
region as it translates SE down the BC coast. Deep cyclogenesis is
fcst by most model guidance over Ern Oregon Wednesday as the flow
backs and increases lift over the aforementioned boundary. As
pressure gradients increase, cold air will then begin to move into
Ern Wa from Srn Bc. Though it`s unusual even to see modest amnts
of agreement among models as to the placement of this deep low 7
days out, there still are enough differences how far south the
low will track that still make our level of confidence low as to where
potentially heavy snow bands may set up Christmas Eve. The trend,
however, has been slightly south which would keep the higher snow
threat out of Nrn Wa. Stay tuned... bz

&&

.AVIATION...
00Z TAFS: A weak weather disturbance is generating light precip
across eastern WA and in the ID Panhandle late this afternoon.
This wave will begin to exit over the course of this evening, but
will be followed by another overnight with more light precip to
fill in across the region. Low level winds will also veer through
tonight, which will result in more favorable upslope flow for
stratus formation. Expect cigs/vis to deteriorate tonight at
KGEG, KSFF, KCOE and KPUW with IFR/MVFR conditions and localized
LIFR conditions possible. /SVH

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        32  37  33  39  31  40 /  50  30  40  90  10  70
Coeur d`Alene  33  38  32  39  32  39 /  60  60  20 100  20  70
Pullman        33  43  34  42  32  43 /  50  40  40  90  10  70
Lewiston       35  45  36  46  33  47 /  40  30  20  70  10  40
Colville       32  37  34  38  32  38 /  60  30  60 100  10  80
Sandpoint      32  37  32  36  31  38 /  60  60  30 100  40  60
Kellogg        32  38  32  36  31  36 /  70  70  20 100  40  60
Moses Lake     29  39  36  42  30  39 /  20  10  70  70  10  70
Wenatchee      31  37  33  40  30  34 /  30  10  70  60  10  70
Omak           27  34  32  37  30  33 /  40  10  80  80  10  80

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$




000
FXUS66 KOTX 172356
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
356 PM PST WED DEC 17 2014

.SYNOPSIS...
A more active weather pattern will continue through the end of the
week with periods of light snow in the mountains...and rain or
snow in the valleys. Lower elevations from Interstate 90 south
will see mainly rain...while areas in the Cascades and near the
Canadian border will remain mainly snow. A much stronger weather
system over the weekend will usher in warmer temperatures with
sharply rising snow levels...as well as the potential for windy
conditions.

&&

.DISCUSSION...

Tonight and Tomorrow...A number of small weak disturbances running
across Eastern Washington and Northern Idaho through tonight and
tomorrow. They are very difficult to pick out in some of the
models as there is too much clutter in the flow associated with
the weakening baroclinic band upon where these disturbances are
located near that is currently passing through the area. They
haven`t been showing up too well in the radar either as they have
been far enough away for most of the day for the base elevation
beam to get a return on as well. Best bet to find these features
has been the IR satellite imagery on a fast rock and picking out
the small scale rotation and cloud top cooling. One such feature
is moving northeast this afternoon and is causing precipitation
just east of Moses Lake up to Omak and some points to the north
and east. A second feature, appearing to almost be a southern part
of the splitting/weakening baroclinic band has brought light rain
to Lewiston. All of these disturbances translate to the Northeast
and East at varying times tonight and tomorrow and as such the
pops and QPF show a general favoring of locations to the North and
East (including locations near Spokane down to Pullman) to receive
some precipitation but as expected the amounts are not too
significant...still it doesn`t take too much liquid to pool on
pavement that in turn cools overnight to allow for slick
conditions in spots similar to what occurred this morning.
/Pelatti

Thursday night through Sunday...An active weather pattern is
expected especially over the weekend with two systems to impacts
the Inland Northwest during this forecast period.

Thursday night/Friday: A large upper low seen on Infrared
Satellite Imagery in the Gulf of Alaska will drop southeast
sending a cold front across the area. The timing of the front
tracks into Central Washington Thursday night during the overnight
hours...reaching Eastern Washington and North Idaho Friday
morning. A north-south oriented jet parallel to the front and
southerly low/mid level flow will minimize downslope flow with all
areas likely to receive some precipitation. Inspection of model
soundings suggest this to be a mainly valley rain or rain/snow
mix...with snow in the mountains. 850mb winds backing to the south
will aid in bring up warmer air from the south. However a wedge of
cooler air trapped along the East Slopes of the Cascades will
result in lower snow levels over North Central Washington with the
potential for 2-3 inches of snow accumulation above 1000-1500
feet. This includes the Methow Valley, Plain, Waterville Plateau,
higher portions of Omak, and Republic. The Wenatchee area and
lower portions of the Okanogan and Columbia River valleys are
expected to see mainly a rain/snow mix or wet non-accumulating
snow. The mountains will generally see 2-5 inches of snow with the
Cascades seeing the highest amounts.

Saturday through Sunday...A much stronger system is expected this
weekend bringing a wide variety of expected weather. The models
continue to show an atmospheric river as a subtropical moisture
fetch becomes aimed at the area. The leading edge of this moisture
will enter on Saturday in the form of a warm front. Strong
isentropic lift will result in the development of widespread
rain and snow. 850mb winds backing to the south-southeast will
favor upslope flow into the northern mountains, with cooler air
remaining banked up into the Cascades, Okanogan Valley, and
Okanogan Highlands. Models suggest the potential for moderate to
locally heavy snow accumulations in these areas along and ahead of
the warm front before snow levels rise from south to north
Saturday night into Sunday morning. Snow levels will be fast to
rise from Interstate 90 south with precip expected to fall as
mainly valley rain and mountain snow. The valleys north of Spokane
such as Colville, Metaline Falls, Priest Lake, and Bonners Ferry
may start off as snow on Saturday with light accumulations...before
changing to rain Saturday night. As the warmer air aloft pokes
into the Cascades Saturday night...the valleys will likely have a
hard time mixing out with freezing rain possible especially south
of Lake Chelan in places like Plain and Leavenworth.

On Sunday the atmospheric river shifts south near the
Washington/Oregon border with strong westerly flow over the area.
This will lead to a strong rain shadow east of the Cascades with
precipitation likely confined mainly to the Cascade crest, Idaho
Panhandle, and southeast Washington. 850mb winds of 25-35 kts and
possible sun breaks across the Columbia Basin...and 850mb temps of
3-6C could lead to very mild temperatures along with breezy to
windy conditions. For now went a bit above MOS guidance which
usually does not go warm enough in these situations. JW

Sunday Nt through Christmas Eve: Following the passage of the windy
and wet short-wave trough that will move through broad upper
ridging Sunday Nt, what`s left of a stalled cold frontal boundary
will remain over Nrn Oregon and extreme Srn Wa Tues and keep the
threat of pcpn in the fcst for the Lewiston area as well as the Camas
Prairie. Where this front stalls will be critical as far as the
Christmas Eve fcst, because it is this boundary that will combine
with a significant short-wave trough and vort max moving into the
region as it translates SE down the BC coast. Deep cyclogenesis is
fcst by most model guidance over Ern Oregon Wednesday as the flow
backs and increases lift over the aforementioned boundary. As
pressure gradients increase, cold air will then begin to move into
Ern Wa from Srn Bc. Though it`s unusual even to see modest amnts
of agreement among models as to the placement of this deep low 7
days out, there still are enough differences how far south the
low will track that still make our level of confidence low as to where
potentially heavy snow bands may set up Christmas Eve. The trend,
however, has been slightly south which would keep the higher snow
threat out of Nrn Wa. Stay tuned... bz

&&

.AVIATION...
00Z TAFS: A weak weather disturbance is generating light precip
across eastern WA and in the ID Panhandle late this afternoon.
This wave will begin to exit over the course of this evening, but
will be followed by another overnight with more light precip to
fill in across the region. Low level winds will also veer through
tonight, which will result in more favorable upslope flow for
stratus formation. Expect cigs/vis to deteriorate tonight at
KGEG, KSFF, KCOE and KPUW with IFR/MVFR conditions and localized
LIFR conditions possible. /SVH

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        32  37  33  39  31  40 /  50  30  40  90  10  70
Coeur d`Alene  33  38  32  39  32  39 /  60  60  20 100  20  70
Pullman        33  43  34  42  32  43 /  50  40  40  90  10  70
Lewiston       35  45  36  46  33  47 /  40  30  20  70  10  40
Colville       32  37  34  38  32  38 /  60  30  60 100  10  80
Sandpoint      32  37  32  36  31  38 /  60  60  30 100  40  60
Kellogg        32  38  32  36  31  36 /  70  70  20 100  40  60
Moses Lake     29  39  36  42  30  39 /  20  10  70  70  10  70
Wenatchee      31  37  33  40  30  34 /  30  10  70  60  10  70
Omak           27  34  32  37  30  33 /  40  10  80  80  10  80

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 172252
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
252 PM PST WED DEC 17 2014

.SYNOPSIS...
A more active weather pattern will continue through the end of the
week with periods of light snow in the mountains...and rain or
snow in the valleys. Lower elevations from Interstate 90 south
will see mainly rain...while areas in the Cascades and near the
Canadian border will remain mainly snow. A much stronger weather
system over the weekend will usher in warmer temperatures with
sharply rising snow levels...as well as the potential for windy
conditions.

&&

.DISCUSSION...

Tonight and Tomorrow...A number of small weak disturbances running
across Eastern Washington and Northern Idaho through tonight and
tomorrow. They are very difficult to pick out in some of the
models as there is too much clutter in the flow associated with
the weakening baroclinic band upon where these disturbances are
located near that is currently passing through the area. They
haven`t been showing up too well in the radar either as they have
been far enough away for most of the day for the base elevation
beam to get a return on as well. Best bet to find these features
has been the IR satellite imagery on a fast rock and picking out
the small scale rotation and cloud top cooling. One such feature
is moving northeast this afternoon and is causing precipitation
just east of Moses Lake up to Omak and some points to the north
and east. A second feature, appearing to almost be a southern part
of the splitting/weakening baroclinic band has brought light rain
to Lewiston. All of these disturbances translate to the Northeast
and East at varying times tonight and tomorrow and as such the
pops and QPF show a general favoring of locations to the North and
East (including locations near Spokane down to Pullman) to receive
some precipitation but as expected the amounts are not too
significant...still it doesn`t take too much liquid to pool on
pavement that in turn cools overnight to allow for slick
conditions in spots similar to what occurred this morning.
/Pelatti

Thursday night through Sunday...An active weather pattern is
expected especially over the weekend with two systems to impacts
the Inland Northwest during this forecast period.

Thursday night/Friday: A large upper low seen on Infrared
Satellite Imagery in the Gulf of Alaska will drop southeast
sending a cold front across the area. The timing of the front
tracks into Central Washington Thursday night during the overnight
hours...reaching Eastern Washington and North Idaho Friday
morning. A north-south oriented jet parallel to the front and
southerly low/mid level flow will minimize downslope flow with all
areas likely to receive some precipitation. Inspection of model
soundings suggest this to be a mainly valley rain or rain/snow
mix...with snow in the mountains. 850mb winds backing to the south
will aid in bring up warmer air from the south. However a wedge of
cooler air trapped along the East Slopes of the Cascades will
result in lower snow levels over North Central Washington with the
potential for 2-3 inches of snow accumulation above 1000-1500
feet. This includes the Methow Valley, Plain, Waterville Plateau,
higher portions of Omak, and Republic. The Wenatchee area and
lower portions of the Okanogan and Columbia River valleys are
expected to see mainly a rain/snow mix or wet non-accumulating
snow. The mountains will generally see 2-5 inches of snow with the
Cascades seeing the highest amounts.

Saturday through Sunday...A much stronger system is expected this
weekend bringing a wide variety of expected weather. The models
continue to show an atmospheric river as a subtropical moisture
fetch becomes aimed at the area. The leading edge of this moisture
will enter on Saturday in the form of a warm front. Strong
isentropic lift will result in the development of widespread
rain and snow. 850mb winds backing to the south-southeast will
favor upslope flow into the northern mountains, with cooler air
remaining banked up into the Cascades, Okanogan Valley, and
Okanogan Highlands. Models suggest the potential for moderate to
locally heavy snow accumulations in these areas along and ahead of
the warm front before snow levels rise from south to north
Saturday night into Sunday morning. Snow levels will be fast to
rise from Interstate 90 south with precip expected to fall as
mainly valley rain and mountain snow. The valleys north of Spokane
such as Colville, Metaline Falls, Priest Lake, and Bonners Ferry
may start off as snow on Saturday with light accumulations...before
changing to rain Saturday night. As the warmer air aloft pokes
into the Cascades Saturday night...the valleys will likely have a
hard time mixing out with freezing rain possible especially south
of Lake Chelan in places like Plain and Leavenworth.

On Sunday the atmospheric river shifts south near the
Washington/Oregon border with strong westerly flow over the area.
This will lead to a strong rain shadow east of the Cascades with
precipitation likely confined mainly to the Cascade crest, Idaho
Panhandle, and southeast Washington. 850mb winds of 25-35 kts and
possible sun breaks across the Columbia Basin...and 850mb temps of
3-6C could lead to very mild temperatures along with breezy to
windy conditions. For now went a bit above MOS guidance which
usually does not go warm enough in these situations. JW

Sunday Nt through Christmas Eve: Following the passage of the windy
and wet short-wave trough that will move through broad upper
ridging Sunday Nt, what`s left of a stalled cold frontal boundary
will remain over Nrn Oregon and extreme Srn Wa Tues and keep the
threat of pcpn in the fcst for the Lewiston area as well as the Camas
Prairie. Where this front stalls will be critical as far as the
Christmas Eve fcst, because it is this boundary that will combine
with a significant short-wave trough and vort max moving into the
region as it translates SE down the BC coast. Deep cyclogenesis is
fcst by most model guidance over Ern Oregon Wednesday as the flow
backs and increases lift over the aforementioned boundary. As
pressure gradients increase, cold air will then begin to move into
Ern Wa from Srn Bc. Though it`s unusual even to see modest amnts
of agreement among models as to the placement of this deep low 7
days out, there still are enough differences how far south the
low will track that still make our level of confidence low as to where
potentially heavy snow bands may set up Christmas Eve. The trend,
however, has been slightly south which would keep the higher snow
threat out of Nrn Wa. Stay tuned... bz

&&

.AVIATION...
18Z TAFS: Weak disturbances drifting northeast and over the
aviation over the next 24 hours keep the forecast somewhat
cluttered with mentions of both rain and snow at times which
produce IFR/LIFR ceilings and visibilities. Some fog will
occasionally impact locations as well. Precipitation still on the
light side with the higher amounts primarily near the East Slopes
of the North Cascades out to the Waterville Plateau and points to
the north/northeast. The KGEG area will be more MVFR most of the
time as the precipitation will be light and likely to be rain.
/Pelatti

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        32  37  33  39  31  40 /  50  30  40  90  10  70
Coeur d`Alene  33  38  32  39  32  39 /  60  60  20 100  20  70
Pullman        33  43  34  42  32  43 /  50  40  40  90  10  70
Lewiston       35  45  36  46  33  47 /  40  30  20  70  10  40
Colville       32  37  34  38  32  38 /  60  30  60 100  10  80
Sandpoint      32  37  32  36  31  38 /  60  60  30 100  40  60
Kellogg        32  38  32  36  31  36 /  70  70  20 100  40  60
Moses Lake     29  39  36  42  30  39 /  20  10  70  70  10  70
Wenatchee      31  37  33  40  30  34 /  30  10  70  60  10  70
Omak           27  34  32  37  30  33 /  40  10  80  80  10  80

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 172252
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
252 PM PST WED DEC 17 2014

.SYNOPSIS...
A more active weather pattern will continue through the end of the
week with periods of light snow in the mountains...and rain or
snow in the valleys. Lower elevations from Interstate 90 south
will see mainly rain...while areas in the Cascades and near the
Canadian border will remain mainly snow. A much stronger weather
system over the weekend will usher in warmer temperatures with
sharply rising snow levels...as well as the potential for windy
conditions.

&&

.DISCUSSION...

Tonight and Tomorrow...A number of small weak disturbances running
across Eastern Washington and Northern Idaho through tonight and
tomorrow. They are very difficult to pick out in some of the
models as there is too much clutter in the flow associated with
the weakening baroclinic band upon where these disturbances are
located near that is currently passing through the area. They
haven`t been showing up too well in the radar either as they have
been far enough away for most of the day for the base elevation
beam to get a return on as well. Best bet to find these features
has been the IR satellite imagery on a fast rock and picking out
the small scale rotation and cloud top cooling. One such feature
is moving northeast this afternoon and is causing precipitation
just east of Moses Lake up to Omak and some points to the north
and east. A second feature, appearing to almost be a southern part
of the splitting/weakening baroclinic band has brought light rain
to Lewiston. All of these disturbances translate to the Northeast
and East at varying times tonight and tomorrow and as such the
pops and QPF show a general favoring of locations to the North and
East (including locations near Spokane down to Pullman) to receive
some precipitation but as expected the amounts are not too
significant...still it doesn`t take too much liquid to pool on
pavement that in turn cools overnight to allow for slick
conditions in spots similar to what occurred this morning.
/Pelatti

Thursday night through Sunday...An active weather pattern is
expected especially over the weekend with two systems to impacts
the Inland Northwest during this forecast period.

Thursday night/Friday: A large upper low seen on Infrared
Satellite Imagery in the Gulf of Alaska will drop southeast
sending a cold front across the area. The timing of the front
tracks into Central Washington Thursday night during the overnight
hours...reaching Eastern Washington and North Idaho Friday
morning. A north-south oriented jet parallel to the front and
southerly low/mid level flow will minimize downslope flow with all
areas likely to receive some precipitation. Inspection of model
soundings suggest this to be a mainly valley rain or rain/snow
mix...with snow in the mountains. 850mb winds backing to the south
will aid in bring up warmer air from the south. However a wedge of
cooler air trapped along the East Slopes of the Cascades will
result in lower snow levels over North Central Washington with the
potential for 2-3 inches of snow accumulation above 1000-1500
feet. This includes the Methow Valley, Plain, Waterville Plateau,
higher portions of Omak, and Republic. The Wenatchee area and
lower portions of the Okanogan and Columbia River valleys are
expected to see mainly a rain/snow mix or wet non-accumulating
snow. The mountains will generally see 2-5 inches of snow with the
Cascades seeing the highest amounts.

Saturday through Sunday...A much stronger system is expected this
weekend bringing a wide variety of expected weather. The models
continue to show an atmospheric river as a subtropical moisture
fetch becomes aimed at the area. The leading edge of this moisture
will enter on Saturday in the form of a warm front. Strong
isentropic lift will result in the development of widespread
rain and snow. 850mb winds backing to the south-southeast will
favor upslope flow into the northern mountains, with cooler air
remaining banked up into the Cascades, Okanogan Valley, and
Okanogan Highlands. Models suggest the potential for moderate to
locally heavy snow accumulations in these areas along and ahead of
the warm front before snow levels rise from south to north
Saturday night into Sunday morning. Snow levels will be fast to
rise from Interstate 90 south with precip expected to fall as
mainly valley rain and mountain snow. The valleys north of Spokane
such as Colville, Metaline Falls, Priest Lake, and Bonners Ferry
may start off as snow on Saturday with light accumulations...before
changing to rain Saturday night. As the warmer air aloft pokes
into the Cascades Saturday night...the valleys will likely have a
hard time mixing out with freezing rain possible especially south
of Lake Chelan in places like Plain and Leavenworth.

On Sunday the atmospheric river shifts south near the
Washington/Oregon border with strong westerly flow over the area.
This will lead to a strong rain shadow east of the Cascades with
precipitation likely confined mainly to the Cascade crest, Idaho
Panhandle, and southeast Washington. 850mb winds of 25-35 kts and
possible sun breaks across the Columbia Basin...and 850mb temps of
3-6C could lead to very mild temperatures along with breezy to
windy conditions. For now went a bit above MOS guidance which
usually does not go warm enough in these situations. JW

Sunday Nt through Christmas Eve: Following the passage of the windy
and wet short-wave trough that will move through broad upper
ridging Sunday Nt, what`s left of a stalled cold frontal boundary
will remain over Nrn Oregon and extreme Srn Wa Tues and keep the
threat of pcpn in the fcst for the Lewiston area as well as the Camas
Prairie. Where this front stalls will be critical as far as the
Christmas Eve fcst, because it is this boundary that will combine
with a significant short-wave trough and vort max moving into the
region as it translates SE down the BC coast. Deep cyclogenesis is
fcst by most model guidance over Ern Oregon Wednesday as the flow
backs and increases lift over the aforementioned boundary. As
pressure gradients increase, cold air will then begin to move into
Ern Wa from Srn Bc. Though it`s unusual even to see modest amnts
of agreement among models as to the placement of this deep low 7
days out, there still are enough differences how far south the
low will track that still make our level of confidence low as to where
potentially heavy snow bands may set up Christmas Eve. The trend,
however, has been slightly south which would keep the higher snow
threat out of Nrn Wa. Stay tuned... bz

&&

.AVIATION...
18Z TAFS: Weak disturbances drifting northeast and over the
aviation over the next 24 hours keep the forecast somewhat
cluttered with mentions of both rain and snow at times which
produce IFR/LIFR ceilings and visibilities. Some fog will
occasionally impact locations as well. Precipitation still on the
light side with the higher amounts primarily near the East Slopes
of the North Cascades out to the Waterville Plateau and points to
the north/northeast. The KGEG area will be more MVFR most of the
time as the precipitation will be light and likely to be rain.
/Pelatti

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        32  37  33  39  31  40 /  50  30  40  90  10  70
Coeur d`Alene  33  38  32  39  32  39 /  60  60  20 100  20  70
Pullman        33  43  34  42  32  43 /  50  40  40  90  10  70
Lewiston       35  45  36  46  33  47 /  40  30  20  70  10  40
Colville       32  37  34  38  32  38 /  60  30  60 100  10  80
Sandpoint      32  37  32  36  31  38 /  60  60  30 100  40  60
Kellogg        32  38  32  36  31  36 /  70  70  20 100  40  60
Moses Lake     29  39  36  42  30  39 /  20  10  70  70  10  70
Wenatchee      31  37  33  40  30  34 /  30  10  70  60  10  70
Omak           27  34  32  37  30  33 /  40  10  80  80  10  80

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$




  [top]

000
FXUS66 KPQR 172252
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
252 PM PST WED DEC 17 2014

.SYNOPSIS...WEAK LOW PRESSURE WILL CROSS THE AREA THIS EVENING WITH
SHOWERS LINGERING OVERNIGHT. EXPECT FAIRLY QUIET WEATHER TO START
THE DAY THURSDAY. A MORE ORGANIZED FRONT WILL BRING GUSTY WINDS TO
THE COAST WITH RAIN SPREADING INLAND THURSDAY NIGHT AND FRIDAY.
RISING SNOW LEVELS WILL LIMIT SNOW TO THE HIGHEST PEAKS. COLDER AIR
BEHIND THE FRONT WILL BRING ACCUMULATING SNOW SHOWERS FOR THE
CASCADES PASSES FRIDAY EVENING AND SATURDAY. MILD AND VERY WET
WEATHER ARRIVED THIS WEEKEND. THERE IS POTENTIAL FOR AN ATMOSPHERIC
RIVER AND ASSOCIATED HEAVY RAIN TO DEVELOP OVER THE AREA AFFECTING
RIVERS INTO NEXT WEEK.

&&

.SHORT TERM...TONIGHT THROUGH SATURDAY...A WEAK AND SPLITTING TROUGH
WILL SEND MOST OF ITS ENERGY SOUTH OF OUR AREA TONIGHT. WILL SEE
SHOWERS TAPER OFF OVERNIGHT AS HIGH PRESSURE BEGINS A TRANSIT ACROSS
THE AREA. WILL ALSO SEE CORRESPONDING SNOW LEVELS RISE ABOVE THE
PASSES AND GENERALLY LIMIT THE AMOUNT OF ACCUMULATIONS. THE RIDGE
AXIS QUICKLY PASSES EAST BY TOMORROW AFTERNOON LEADING TO A LARGELY
DRY DAY FOR THE INTERIOR.

ANOTHER MORE COHESIVE TROUGH AND FRONTAL SYSTEM WILL DIG OFFSHORE
WITH WARM FRONTAL RAIN TOUCHING THE COAST LATE FRIDAY AFTERNOON WITH
HEAVIER AMOUNTS BY EARLY FRIDAY EVENING. TIMING COULD BE EARLIER
DEPENDING ON MODEL OF CHOICE WITH THE GFS PERHAPS A COUPLE HOURS
FASTER THAN THE ECMWF AND THE NAM SLOWER YET. NAM TYPICALLY DOES NOT
HANDLE WARM PROCESS RAIN VERY WELL SO AM PUTTING LESS WEIGHT ON IT
TO START WITH. AS THE RAIN COMES IN...A COASTAL JET DEVELOPS
BRINGING FAIRLY GUSTY WINDS TO THE COAST AND COAST RANGE BUT NOTHING
TOO OUT OF THE ORDINARY. NOT ANTICIPATING ANY HIGHLIGHTS BUT
PROBABLY A RUN OF THE MILL WINDY COASTAL STORM. THE ASSOCIATED COLD
FRONT COME ASHORE AROUND 12Z FRIDAY MORNING AND CROSSES THE CASCADES
AROUND 17Z WITH COLDER AIR AND LOWERING SNOW LEVELS WITH AND MORE SO
BEHIND IT. PRECIPITATION TAPERS OFF AND BECOMES MORE SHOWERY IN
NATURE BEHIND THE FRONT. EXPECT LIGHT ACCUMULATING SNOW BEGINS AT
WILLAMETTE PASS AROUND DAY BREAK AND LOWERS TO NEAR GOVERNMENT PASS
LATER THAT MORNING. THE SNOW COMES TO BE TOO LITTLE...TOO LATE FOR
MUCH APPRECIABLE INCREASE IN THE SNOW PACK WITH PERHAPS A FEW INCHES
AT THE HIGHER PASSES AND LESS THAN AN INCH FOR GOVERNMENT CAMP.
HIGHER PEAKS COULD SEE UP TO A FOOT...HOWEVER. ANY OF THE MID
ELEVATION SNOW WILL BE RATHER SHORT-LIVED AS SNOW LEVELS IMMEDIATELY
BEGIN RISING IN ANTICIPATION OF THE PACIFIC STORM TRACK BECOMING
CENTERED OVER THE AREA.

MAIN ATTENTION THIS SHIFT HAS BEEN BE PLACED ON THE ATMOSPHERIC
RIVER EVENT SETTING UP TO AFFECT THE REGION THIS WEEKEND WITH
IMPACTS LASTING INTO NEXT WEEK. RAW GFS MODEL RUN ACCUMULATED QPF
AMOUNTS EXCEED 12 INCHES FOR PORTIONS OF THE CASCADES AND 10 INCHES
FOR THE COAST RANGE ENDING MONDAY MORNING. WILL SEE THE WARM RAINS
BEGIN AFFECTING THE COAST RANGE SATURDAY MORNING AND PUSH QUICKLY
INLAND TO THE CASCADES BY SATURDAY AFTERNOON. MOST OF THE HEAVY RAIN
OCCURS BEGINNING SATURDAY NIGHT. THERE WOULD BE DEEP WESTERLY FLOW
FROM THE SURFACE UP TO THE JET LEVEL THUS EXPECT THIS COULD BE AN
IDEAL OROGRAPHIC SITUATION TO EXTRACT A MAXIMUM AMOUNT OF RAIN FROM
WHATEVER COMES ASHORE. THERE IS GENERAL LARGE SCALE SUPPORT FROM THE
ECMWF ALBEIT WITH LESS QPF. PAST EXPERIENCE SHOWS FOLLOWING THE
HIGHER GFS QPF AMOUNTS IS STILL NOT ENOUGH AND THAT REALITY BRINGS
SIGNIFICANTLY MORE RAIN. ASSUMING THE CURRENT MODEL RUNS STAY
UNCHANGED IN THE FUTURE...WOULD EXPECT MULTIPLE MAINSTEM RIVERS
EXCEEDING FLOOD STAGE AS SOON AS SUNDAY EVENING.

HAVE ISSUED SOME OUTLOOK PRODUCTS TODAY LOOKING AHEAD TO FLOODING
POTENTIAL WITH THE CAVEAT THAT MODELS HAVE SHIFTED THE FOCUS FROM
NORTHERN WASHINGTON/BRITISH COLUMBIA SOUTH TO OUR AREA DURING THE
PAST 36 HOURS. ADDITIONAL SHIFTING IS EXPECTED AS WELL AS TIMING
DIFFERENCES. STAY TUNED AS THIS SITUATION EVOLVES OVER TIME.
/JBONK

.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY...MODELS MAINTAIN A
FLATTENED RIDGE OVER THE EASTERN PACIFIC FOR THE WEEKEND THROUGH
EARLY NEXT WEEK. WITH A NEARLY ZONAL JET AND ABUNDANT
MOISTURE...EXPECT PLENTY OF RAINFALL TO CONTINUE THROUGH SUNDAY. ON
MONDAY AND TUESDAY...SOME WEAK RIDGING MOVES OVER THE REGION BUT
SHOWERS LIKELY CONTINUE IN THE MOIST ONSHORE FLOW. AN UPPER TROUGH
DROPS SOUTH OVER THE REGION BY MIDWEEK WITH SOME RATHER COLD AIR AND
ADDITIONAL PRECIPITATION IN STORE. WHILE STILL SOME SIGNIFICANT
UNCERTAINTY EXISTS WITH RESPECT TO THE TIMING OF THE PRECIP VS COLD
AIR AND JUST HOW COLD THE AIR IS...IT DOES APPEAR THAT A SIGNIFICANT
SURGE OF COLD AIR MAY MOVE INTO THE REGION AND THEREFORE...DECREASED
TEMPERATURES ACCORDINGLY FOR THE TUE/WED PERIODS ACROSS THE REGION.
IT DOES APPEAR THAT SNOW LEVELS WILL DROP BELOW PASS LEVELS AT
LEAST...AND PERHAPS DOWN INTO THE FOOTHILL ELEVATIONS LATER
WEDNESDAY INTO THURSDAY. GIVEN THE UNCERTAINTY...THOSE PLANNING
HOLIDAY TRAVEL DURING THIS PERIOD SHOULD MONITOR THE FORECAST.
CULLEN

&&

.AVIATION...VFR CONDITIONS LIKELY TO CONTINUE THROUGH THIS
AFTERNOON. ONSHORE WINDS THIS EVENING BEHIND THE WEAK LOW MOVING
ONSHORE WILL ALLOW FOR CIGS AND VIS TO LOWER TO IFR TONIGHT WITH
THE DEVELOPMENT OF FOG/LOW STRATUS. THIS SHOULD HOLD ON THROUGH
THURSDAY MORNING...STARTING TO LIFT BACK TOWARD VFR AROUND 15 TO 18Z
THURSDAY AS WINDS START TO INCREASE OUT OF THE SOUTH. VFR WILL
CONTINUE THROUGH THURSDAY AFTERNOON...THOUGH LOW-LEVEL WIND SHEAR
WILL BE A CONCERN AT KTTD AND POSSIBLY KPDX AS 20 KT EASTERLY
WINDS FROM THE GORGE UNDERCUT INCREASING SOUTHERLY WINDS ALOFT.

KPDX AND APPROACHES...VFR CONDITIONS TO PERSIST THIS
EVENING. WEAK WINDS WILL COULD PROMOTE THE DEVELOPMENT OF FOG/LOW
STRATUS AFTER 06Z THURSDAY...DROPPING CIGS AND VIS TO IFR. THIS
SHOULD LIFT BACK TO VFR BY 18Z THURSDAY. -MCCOY

&&

.MARINE...WEAK LOW PRESSURE SYSTEM MOVING NORTHWARD ALONG THE
COAST HAS BROUGHT WINDS UP TO SCA CRITERIA THIS AFTERNOON IN OUR
SOUTHERN WATERS. THIS IS WEAKENING AND MOVING ONSHORE...WHICH
SHOULD ALLOW WINDS TO SUBSIDE FOR A BRIEF PERIOD THIS EVENING.
WINDS WILL BEGIN TO INCREASE ACROSS OUR WATERS THURSDAY MORNING
AHEAD OF A COLD FRONT WHICH WILL MOVE THROUGH OUR WATERS DURING
THE DAY THURSDAY. AHEAD OF THIS FRONT...WINDS LIKELY TO RAMP UP TO
GALE FORCE WITH A COASTAL JET FULLY DEVELOPED BY THURSDAY
EVENING AND PERSIST UNTIL THE FRONT MOVES ONSHORE EARLY FRIDAY
MORNING.

SEAS CURRENTLY AROUND 10-12 FT WILL DROP TO 9 FT LATER THIS
EVENING. SEAS WILL BEGIN TO BUILD AGAIN THURSDAY MORNING AS WINDS
INCREASE AHEAD OF THE COLD FRONT ON THURSDAY. SEAS EXPECTED TO
BUILD TO THE LOW-TO-MIDDLE TEENS THURSDAY EVENING...SUBSIDING TO
10 TO 12 FT EARLY FRIDAY MORNING. A DYNAMIC FETCH APPROACHES EARLY
FRIDAY...BRINGING A LARGE SWELL INTO OUR WATERS. THIS WILL CAUSE
SEAS TO RAPIDLY BUILD FRIDAY MORNING...REACHING 20 FT FRIDAY
EVENING. THE NEXT STRONG FRONT APPROACHES ON SATURDAY...WITH
GALES POSSIBLE...COULD BUILD SEAS ALREADY 15 TO 20 FEET...TO 20
TO 25 FT SATURDAY. -MCCOY

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 4 AM TO 1 PM PST THURSDAY
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 60 NM.

     GALE WARNING FROM 1 PM THURSDAY TO MIDNIGHT PST THURSDAY NIGHT
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 9 PM PST THIS
     EVENING FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR WINDS UNTIL 1 PM PST THURSDAY FOR
     COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 4 AM PST THURSDAY.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.




000
FXUS66 KPQR 172252
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
252 PM PST WED DEC 17 2014

.SYNOPSIS...WEAK LOW PRESSURE WILL CROSS THE AREA THIS EVENING WITH
SHOWERS LINGERING OVERNIGHT. EXPECT FAIRLY QUIET WEATHER TO START
THE DAY THURSDAY. A MORE ORGANIZED FRONT WILL BRING GUSTY WINDS TO
THE COAST WITH RAIN SPREADING INLAND THURSDAY NIGHT AND FRIDAY.
RISING SNOW LEVELS WILL LIMIT SNOW TO THE HIGHEST PEAKS. COLDER AIR
BEHIND THE FRONT WILL BRING ACCUMULATING SNOW SHOWERS FOR THE
CASCADES PASSES FRIDAY EVENING AND SATURDAY. MILD AND VERY WET
WEATHER ARRIVED THIS WEEKEND. THERE IS POTENTIAL FOR AN ATMOSPHERIC
RIVER AND ASSOCIATED HEAVY RAIN TO DEVELOP OVER THE AREA AFFECTING
RIVERS INTO NEXT WEEK.

&&

.SHORT TERM...TONIGHT THROUGH SATURDAY...A WEAK AND SPLITTING TROUGH
WILL SEND MOST OF ITS ENERGY SOUTH OF OUR AREA TONIGHT. WILL SEE
SHOWERS TAPER OFF OVERNIGHT AS HIGH PRESSURE BEGINS A TRANSIT ACROSS
THE AREA. WILL ALSO SEE CORRESPONDING SNOW LEVELS RISE ABOVE THE
PASSES AND GENERALLY LIMIT THE AMOUNT OF ACCUMULATIONS. THE RIDGE
AXIS QUICKLY PASSES EAST BY TOMORROW AFTERNOON LEADING TO A LARGELY
DRY DAY FOR THE INTERIOR.

ANOTHER MORE COHESIVE TROUGH AND FRONTAL SYSTEM WILL DIG OFFSHORE
WITH WARM FRONTAL RAIN TOUCHING THE COAST LATE FRIDAY AFTERNOON WITH
HEAVIER AMOUNTS BY EARLY FRIDAY EVENING. TIMING COULD BE EARLIER
DEPENDING ON MODEL OF CHOICE WITH THE GFS PERHAPS A COUPLE HOURS
FASTER THAN THE ECMWF AND THE NAM SLOWER YET. NAM TYPICALLY DOES NOT
HANDLE WARM PROCESS RAIN VERY WELL SO AM PUTTING LESS WEIGHT ON IT
TO START WITH. AS THE RAIN COMES IN...A COASTAL JET DEVELOPS
BRINGING FAIRLY GUSTY WINDS TO THE COAST AND COAST RANGE BUT NOTHING
TOO OUT OF THE ORDINARY. NOT ANTICIPATING ANY HIGHLIGHTS BUT
PROBABLY A RUN OF THE MILL WINDY COASTAL STORM. THE ASSOCIATED COLD
FRONT COME ASHORE AROUND 12Z FRIDAY MORNING AND CROSSES THE CASCADES
AROUND 17Z WITH COLDER AIR AND LOWERING SNOW LEVELS WITH AND MORE SO
BEHIND IT. PRECIPITATION TAPERS OFF AND BECOMES MORE SHOWERY IN
NATURE BEHIND THE FRONT. EXPECT LIGHT ACCUMULATING SNOW BEGINS AT
WILLAMETTE PASS AROUND DAY BREAK AND LOWERS TO NEAR GOVERNMENT PASS
LATER THAT MORNING. THE SNOW COMES TO BE TOO LITTLE...TOO LATE FOR
MUCH APPRECIABLE INCREASE IN THE SNOW PACK WITH PERHAPS A FEW INCHES
AT THE HIGHER PASSES AND LESS THAN AN INCH FOR GOVERNMENT CAMP.
HIGHER PEAKS COULD SEE UP TO A FOOT...HOWEVER. ANY OF THE MID
ELEVATION SNOW WILL BE RATHER SHORT-LIVED AS SNOW LEVELS IMMEDIATELY
BEGIN RISING IN ANTICIPATION OF THE PACIFIC STORM TRACK BECOMING
CENTERED OVER THE AREA.

MAIN ATTENTION THIS SHIFT HAS BEEN BE PLACED ON THE ATMOSPHERIC
RIVER EVENT SETTING UP TO AFFECT THE REGION THIS WEEKEND WITH
IMPACTS LASTING INTO NEXT WEEK. RAW GFS MODEL RUN ACCUMULATED QPF
AMOUNTS EXCEED 12 INCHES FOR PORTIONS OF THE CASCADES AND 10 INCHES
FOR THE COAST RANGE ENDING MONDAY MORNING. WILL SEE THE WARM RAINS
BEGIN AFFECTING THE COAST RANGE SATURDAY MORNING AND PUSH QUICKLY
INLAND TO THE CASCADES BY SATURDAY AFTERNOON. MOST OF THE HEAVY RAIN
OCCURS BEGINNING SATURDAY NIGHT. THERE WOULD BE DEEP WESTERLY FLOW
FROM THE SURFACE UP TO THE JET LEVEL THUS EXPECT THIS COULD BE AN
IDEAL OROGRAPHIC SITUATION TO EXTRACT A MAXIMUM AMOUNT OF RAIN FROM
WHATEVER COMES ASHORE. THERE IS GENERAL LARGE SCALE SUPPORT FROM THE
ECMWF ALBEIT WITH LESS QPF. PAST EXPERIENCE SHOWS FOLLOWING THE
HIGHER GFS QPF AMOUNTS IS STILL NOT ENOUGH AND THAT REALITY BRINGS
SIGNIFICANTLY MORE RAIN. ASSUMING THE CURRENT MODEL RUNS STAY
UNCHANGED IN THE FUTURE...WOULD EXPECT MULTIPLE MAINSTEM RIVERS
EXCEEDING FLOOD STAGE AS SOON AS SUNDAY EVENING.

HAVE ISSUED SOME OUTLOOK PRODUCTS TODAY LOOKING AHEAD TO FLOODING
POTENTIAL WITH THE CAVEAT THAT MODELS HAVE SHIFTED THE FOCUS FROM
NORTHERN WASHINGTON/BRITISH COLUMBIA SOUTH TO OUR AREA DURING THE
PAST 36 HOURS. ADDITIONAL SHIFTING IS EXPECTED AS WELL AS TIMING
DIFFERENCES. STAY TUNED AS THIS SITUATION EVOLVES OVER TIME.
/JBONK

.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY...MODELS MAINTAIN A
FLATTENED RIDGE OVER THE EASTERN PACIFIC FOR THE WEEKEND THROUGH
EARLY NEXT WEEK. WITH A NEARLY ZONAL JET AND ABUNDANT
MOISTURE...EXPECT PLENTY OF RAINFALL TO CONTINUE THROUGH SUNDAY. ON
MONDAY AND TUESDAY...SOME WEAK RIDGING MOVES OVER THE REGION BUT
SHOWERS LIKELY CONTINUE IN THE MOIST ONSHORE FLOW. AN UPPER TROUGH
DROPS SOUTH OVER THE REGION BY MIDWEEK WITH SOME RATHER COLD AIR AND
ADDITIONAL PRECIPITATION IN STORE. WHILE STILL SOME SIGNIFICANT
UNCERTAINTY EXISTS WITH RESPECT TO THE TIMING OF THE PRECIP VS COLD
AIR AND JUST HOW COLD THE AIR IS...IT DOES APPEAR THAT A SIGNIFICANT
SURGE OF COLD AIR MAY MOVE INTO THE REGION AND THEREFORE...DECREASED
TEMPERATURES ACCORDINGLY FOR THE TUE/WED PERIODS ACROSS THE REGION.
IT DOES APPEAR THAT SNOW LEVELS WILL DROP BELOW PASS LEVELS AT
LEAST...AND PERHAPS DOWN INTO THE FOOTHILL ELEVATIONS LATER
WEDNESDAY INTO THURSDAY. GIVEN THE UNCERTAINTY...THOSE PLANNING
HOLIDAY TRAVEL DURING THIS PERIOD SHOULD MONITOR THE FORECAST.
CULLEN

&&

.AVIATION...VFR CONDITIONS LIKELY TO CONTINUE THROUGH THIS
AFTERNOON. ONSHORE WINDS THIS EVENING BEHIND THE WEAK LOW MOVING
ONSHORE WILL ALLOW FOR CIGS AND VIS TO LOWER TO IFR TONIGHT WITH
THE DEVELOPMENT OF FOG/LOW STRATUS. THIS SHOULD HOLD ON THROUGH
THURSDAY MORNING...STARTING TO LIFT BACK TOWARD VFR AROUND 15 TO 18Z
THURSDAY AS WINDS START TO INCREASE OUT OF THE SOUTH. VFR WILL
CONTINUE THROUGH THURSDAY AFTERNOON...THOUGH LOW-LEVEL WIND SHEAR
WILL BE A CONCERN AT KTTD AND POSSIBLY KPDX AS 20 KT EASTERLY
WINDS FROM THE GORGE UNDERCUT INCREASING SOUTHERLY WINDS ALOFT.

KPDX AND APPROACHES...VFR CONDITIONS TO PERSIST THIS
EVENING. WEAK WINDS WILL COULD PROMOTE THE DEVELOPMENT OF FOG/LOW
STRATUS AFTER 06Z THURSDAY...DROPPING CIGS AND VIS TO IFR. THIS
SHOULD LIFT BACK TO VFR BY 18Z THURSDAY. -MCCOY

&&

.MARINE...WEAK LOW PRESSURE SYSTEM MOVING NORTHWARD ALONG THE
COAST HAS BROUGHT WINDS UP TO SCA CRITERIA THIS AFTERNOON IN OUR
SOUTHERN WATERS. THIS IS WEAKENING AND MOVING ONSHORE...WHICH
SHOULD ALLOW WINDS TO SUBSIDE FOR A BRIEF PERIOD THIS EVENING.
WINDS WILL BEGIN TO INCREASE ACROSS OUR WATERS THURSDAY MORNING
AHEAD OF A COLD FRONT WHICH WILL MOVE THROUGH OUR WATERS DURING
THE DAY THURSDAY. AHEAD OF THIS FRONT...WINDS LIKELY TO RAMP UP TO
GALE FORCE WITH A COASTAL JET FULLY DEVELOPED BY THURSDAY
EVENING AND PERSIST UNTIL THE FRONT MOVES ONSHORE EARLY FRIDAY
MORNING.

SEAS CURRENTLY AROUND 10-12 FT WILL DROP TO 9 FT LATER THIS
EVENING. SEAS WILL BEGIN TO BUILD AGAIN THURSDAY MORNING AS WINDS
INCREASE AHEAD OF THE COLD FRONT ON THURSDAY. SEAS EXPECTED TO
BUILD TO THE LOW-TO-MIDDLE TEENS THURSDAY EVENING...SUBSIDING TO
10 TO 12 FT EARLY FRIDAY MORNING. A DYNAMIC FETCH APPROACHES EARLY
FRIDAY...BRINGING A LARGE SWELL INTO OUR WATERS. THIS WILL CAUSE
SEAS TO RAPIDLY BUILD FRIDAY MORNING...REACHING 20 FT FRIDAY
EVENING. THE NEXT STRONG FRONT APPROACHES ON SATURDAY...WITH
GALES POSSIBLE...COULD BUILD SEAS ALREADY 15 TO 20 FEET...TO 20
TO 25 FT SATURDAY. -MCCOY

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 4 AM TO 1 PM PST THURSDAY
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 60 NM.

     GALE WARNING FROM 1 PM THURSDAY TO MIDNIGHT PST THURSDAY NIGHT
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 9 PM PST THIS
     EVENING FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR WINDS UNTIL 1 PM PST THURSDAY FOR
     COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 4 AM PST THURSDAY.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.




000
FXUS66 KOTX 172252
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
252 PM PST WED DEC 17 2014

.SYNOPSIS...
A more active weather pattern will continue through the end of the
week with periods of light snow in the mountains...and rain or
snow in the valleys. Lower elevations from Interstate 90 south
will see mainly rain...while areas in the Cascades and near the
Canadian border will remain mainly snow. A much stronger weather
system over the weekend will usher in warmer temperatures with
sharply rising snow levels...as well as the potential for windy
conditions.

&&

.DISCUSSION...

Tonight and Tomorrow...A number of small weak disturbances running
across Eastern Washington and Northern Idaho through tonight and
tomorrow. They are very difficult to pick out in some of the
models as there is too much clutter in the flow associated with
the weakening baroclinic band upon where these disturbances are
located near that is currently passing through the area. They
haven`t been showing up too well in the radar either as they have
been far enough away for most of the day for the base elevation
beam to get a return on as well. Best bet to find these features
has been the IR satellite imagery on a fast rock and picking out
the small scale rotation and cloud top cooling. One such feature
is moving northeast this afternoon and is causing precipitation
just east of Moses Lake up to Omak and some points to the north
and east. A second feature, appearing to almost be a southern part
of the splitting/weakening baroclinic band has brought light rain
to Lewiston. All of these disturbances translate to the Northeast
and East at varying times tonight and tomorrow and as such the
pops and QPF show a general favoring of locations to the North and
East (including locations near Spokane down to Pullman) to receive
some precipitation but as expected the amounts are not too
significant...still it doesn`t take too much liquid to pool on
pavement that in turn cools overnight to allow for slick
conditions in spots similar to what occurred this morning.
/Pelatti

Thursday night through Sunday...An active weather pattern is
expected especially over the weekend with two systems to impacts
the Inland Northwest during this forecast period.

Thursday night/Friday: A large upper low seen on Infrared
Satellite Imagery in the Gulf of Alaska will drop southeast
sending a cold front across the area. The timing of the front
tracks into Central Washington Thursday night during the overnight
hours...reaching Eastern Washington and North Idaho Friday
morning. A north-south oriented jet parallel to the front and
southerly low/mid level flow will minimize downslope flow with all
areas likely to receive some precipitation. Inspection of model
soundings suggest this to be a mainly valley rain or rain/snow
mix...with snow in the mountains. 850mb winds backing to the south
will aid in bring up warmer air from the south. However a wedge of
cooler air trapped along the East Slopes of the Cascades will
result in lower snow levels over North Central Washington with the
potential for 2-3 inches of snow accumulation above 1000-1500
feet. This includes the Methow Valley, Plain, Waterville Plateau,
higher portions of Omak, and Republic. The Wenatchee area and
lower portions of the Okanogan and Columbia River valleys are
expected to see mainly a rain/snow mix or wet non-accumulating
snow. The mountains will generally see 2-5 inches of snow with the
Cascades seeing the highest amounts.

Saturday through Sunday...A much stronger system is expected this
weekend bringing a wide variety of expected weather. The models
continue to show an atmospheric river as a subtropical moisture
fetch becomes aimed at the area. The leading edge of this moisture
will enter on Saturday in the form of a warm front. Strong
isentropic lift will result in the development of widespread
rain and snow. 850mb winds backing to the south-southeast will
favor upslope flow into the northern mountains, with cooler air
remaining banked up into the Cascades, Okanogan Valley, and
Okanogan Highlands. Models suggest the potential for moderate to
locally heavy snow accumulations in these areas along and ahead of
the warm front before snow levels rise from south to north
Saturday night into Sunday morning. Snow levels will be fast to
rise from Interstate 90 south with precip expected to fall as
mainly valley rain and mountain snow. The valleys north of Spokane
such as Colville, Metaline Falls, Priest Lake, and Bonners Ferry
may start off as snow on Saturday with light accumulations...before
changing to rain Saturday night. As the warmer air aloft pokes
into the Cascades Saturday night...the valleys will likely have a
hard time mixing out with freezing rain possible especially south
of Lake Chelan in places like Plain and Leavenworth.

On Sunday the atmospheric river shifts south near the
Washington/Oregon border with strong westerly flow over the area.
This will lead to a strong rain shadow east of the Cascades with
precipitation likely confined mainly to the Cascade crest, Idaho
Panhandle, and southeast Washington. 850mb winds of 25-35 kts and
possible sun breaks across the Columbia Basin...and 850mb temps of
3-6C could lead to very mild temperatures along with breezy to
windy conditions. For now went a bit above MOS guidance which
usually does not go warm enough in these situations. JW

Sunday Nt through Christmas Eve: Following the passage of the windy
and wet short-wave trough that will move through broad upper
ridging Sunday Nt, what`s left of a stalled cold frontal boundary
will remain over Nrn Oregon and extreme Srn Wa Tues and keep the
threat of pcpn in the fcst for the Lewiston area as well as the Camas
Prairie. Where this front stalls will be critical as far as the
Christmas Eve fcst, because it is this boundary that will combine
with a significant short-wave trough and vort max moving into the
region as it translates SE down the BC coast. Deep cyclogenesis is
fcst by most model guidance over Ern Oregon Wednesday as the flow
backs and increases lift over the aforementioned boundary. As
pressure gradients increase, cold air will then begin to move into
Ern Wa from Srn Bc. Though it`s unusual even to see modest amnts
of agreement among models as to the placement of this deep low 7
days out, there still are enough differences how far south the
low will track that still make our level of confidence low as to where
potentially heavy snow bands may set up Christmas Eve. The trend,
however, has been slightly south which would keep the higher snow
threat out of Nrn Wa. Stay tuned... bz

&&

.AVIATION...
18Z TAFS: Weak disturbances drifting northeast and over the
aviation over the next 24 hours keep the forecast somewhat
cluttered with mentions of both rain and snow at times which
produce IFR/LIFR ceilings and visibilities. Some fog will
occasionally impact locations as well. Precipitation still on the
light side with the higher amounts primarily near the East Slopes
of the North Cascades out to the Waterville Plateau and points to
the north/northeast. The KGEG area will be more MVFR most of the
time as the precipitation will be light and likely to be rain.
/Pelatti

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        32  37  33  39  31  40 /  50  30  40  90  10  70
Coeur d`Alene  33  38  32  39  32  39 /  60  60  20 100  20  70
Pullman        33  43  34  42  32  43 /  50  40  40  90  10  70
Lewiston       35  45  36  46  33  47 /  40  30  20  70  10  40
Colville       32  37  34  38  32  38 /  60  30  60 100  10  80
Sandpoint      32  37  32  36  31  38 /  60  60  30 100  40  60
Kellogg        32  38  32  36  31  36 /  70  70  20 100  40  60
Moses Lake     29  39  36  42  30  39 /  20  10  70  70  10  70
Wenatchee      31  37  33  40  30  34 /  30  10  70  60  10  70
Omak           27  34  32  37  30  33 /  40  10  80  80  10  80

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 172252
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
252 PM PST WED DEC 17 2014

.SYNOPSIS...
A more active weather pattern will continue through the end of the
week with periods of light snow in the mountains...and rain or
snow in the valleys. Lower elevations from Interstate 90 south
will see mainly rain...while areas in the Cascades and near the
Canadian border will remain mainly snow. A much stronger weather
system over the weekend will usher in warmer temperatures with
sharply rising snow levels...as well as the potential for windy
conditions.

&&

.DISCUSSION...

Tonight and Tomorrow...A number of small weak disturbances running
across Eastern Washington and Northern Idaho through tonight and
tomorrow. They are very difficult to pick out in some of the
models as there is too much clutter in the flow associated with
the weakening baroclinic band upon where these disturbances are
located near that is currently passing through the area. They
haven`t been showing up too well in the radar either as they have
been far enough away for most of the day for the base elevation
beam to get a return on as well. Best bet to find these features
has been the IR satellite imagery on a fast rock and picking out
the small scale rotation and cloud top cooling. One such feature
is moving northeast this afternoon and is causing precipitation
just east of Moses Lake up to Omak and some points to the north
and east. A second feature, appearing to almost be a southern part
of the splitting/weakening baroclinic band has brought light rain
to Lewiston. All of these disturbances translate to the Northeast
and East at varying times tonight and tomorrow and as such the
pops and QPF show a general favoring of locations to the North and
East (including locations near Spokane down to Pullman) to receive
some precipitation but as expected the amounts are not too
significant...still it doesn`t take too much liquid to pool on
pavement that in turn cools overnight to allow for slick
conditions in spots similar to what occurred this morning.
/Pelatti

Thursday night through Sunday...An active weather pattern is
expected especially over the weekend with two systems to impacts
the Inland Northwest during this forecast period.

Thursday night/Friday: A large upper low seen on Infrared
Satellite Imagery in the Gulf of Alaska will drop southeast
sending a cold front across the area. The timing of the front
tracks into Central Washington Thursday night during the overnight
hours...reaching Eastern Washington and North Idaho Friday
morning. A north-south oriented jet parallel to the front and
southerly low/mid level flow will minimize downslope flow with all
areas likely to receive some precipitation. Inspection of model
soundings suggest this to be a mainly valley rain or rain/snow
mix...with snow in the mountains. 850mb winds backing to the south
will aid in bring up warmer air from the south. However a wedge of
cooler air trapped along the East Slopes of the Cascades will
result in lower snow levels over North Central Washington with the
potential for 2-3 inches of snow accumulation above 1000-1500
feet. This includes the Methow Valley, Plain, Waterville Plateau,
higher portions of Omak, and Republic. The Wenatchee area and
lower portions of the Okanogan and Columbia River valleys are
expected to see mainly a rain/snow mix or wet non-accumulating
snow. The mountains will generally see 2-5 inches of snow with the
Cascades seeing the highest amounts.

Saturday through Sunday...A much stronger system is expected this
weekend bringing a wide variety of expected weather. The models
continue to show an atmospheric river as a subtropical moisture
fetch becomes aimed at the area. The leading edge of this moisture
will enter on Saturday in the form of a warm front. Strong
isentropic lift will result in the development of widespread
rain and snow. 850mb winds backing to the south-southeast will
favor upslope flow into the northern mountains, with cooler air
remaining banked up into the Cascades, Okanogan Valley, and
Okanogan Highlands. Models suggest the potential for moderate to
locally heavy snow accumulations in these areas along and ahead of
the warm front before snow levels rise from south to north
Saturday night into Sunday morning. Snow levels will be fast to
rise from Interstate 90 south with precip expected to fall as
mainly valley rain and mountain snow. The valleys north of Spokane
such as Colville, Metaline Falls, Priest Lake, and Bonners Ferry
may start off as snow on Saturday with light accumulations...before
changing to rain Saturday night. As the warmer air aloft pokes
into the Cascades Saturday night...the valleys will likely have a
hard time mixing out with freezing rain possible especially south
of Lake Chelan in places like Plain and Leavenworth.

On Sunday the atmospheric river shifts south near the
Washington/Oregon border with strong westerly flow over the area.
This will lead to a strong rain shadow east of the Cascades with
precipitation likely confined mainly to the Cascade crest, Idaho
Panhandle, and southeast Washington. 850mb winds of 25-35 kts and
possible sun breaks across the Columbia Basin...and 850mb temps of
3-6C could lead to very mild temperatures along with breezy to
windy conditions. For now went a bit above MOS guidance which
usually does not go warm enough in these situations. JW

Sunday Nt through Christmas Eve: Following the passage of the windy
and wet short-wave trough that will move through broad upper
ridging Sunday Nt, what`s left of a stalled cold frontal boundary
will remain over Nrn Oregon and extreme Srn Wa Tues and keep the
threat of pcpn in the fcst for the Lewiston area as well as the Camas
Prairie. Where this front stalls will be critical as far as the
Christmas Eve fcst, because it is this boundary that will combine
with a significant short-wave trough and vort max moving into the
region as it translates SE down the BC coast. Deep cyclogenesis is
fcst by most model guidance over Ern Oregon Wednesday as the flow
backs and increases lift over the aforementioned boundary. As
pressure gradients increase, cold air will then begin to move into
Ern Wa from Srn Bc. Though it`s unusual even to see modest amnts
of agreement among models as to the placement of this deep low 7
days out, there still are enough differences how far south the
low will track that still make our level of confidence low as to where
potentially heavy snow bands may set up Christmas Eve. The trend,
however, has been slightly south which would keep the higher snow
threat out of Nrn Wa. Stay tuned... bz

&&

.AVIATION...
18Z TAFS: Weak disturbances drifting northeast and over the
aviation over the next 24 hours keep the forecast somewhat
cluttered with mentions of both rain and snow at times which
produce IFR/LIFR ceilings and visibilities. Some fog will
occasionally impact locations as well. Precipitation still on the
light side with the higher amounts primarily near the East Slopes
of the North Cascades out to the Waterville Plateau and points to
the north/northeast. The KGEG area will be more MVFR most of the
time as the precipitation will be light and likely to be rain.
/Pelatti

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        32  37  33  39  31  40 /  50  30  40  90  10  70
Coeur d`Alene  33  38  32  39  32  39 /  60  60  20 100  20  70
Pullman        33  43  34  42  32  43 /  50  40  40  90  10  70
Lewiston       35  45  36  46  33  47 /  40  30  20  70  10  40
Colville       32  37  34  38  32  38 /  60  30  60 100  10  80
Sandpoint      32  37  32  36  31  38 /  60  60  30 100  40  60
Kellogg        32  38  32  36  31  36 /  70  70  20 100  40  60
Moses Lake     29  39  36  42  30  39 /  20  10  70  70  10  70
Wenatchee      31  37  33  40  30  34 /  30  10  70  60  10  70
Omak           27  34  32  37  30  33 /  40  10  80  80  10  80

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KPQR 172252
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
252 PM PST WED DEC 17 2014

.SYNOPSIS...WEAK LOW PRESSURE WILL CROSS THE AREA THIS EVENING WITH
SHOWERS LINGERING OVERNIGHT. EXPECT FAIRLY QUIET WEATHER TO START
THE DAY THURSDAY. A MORE ORGANIZED FRONT WILL BRING GUSTY WINDS TO
THE COAST WITH RAIN SPREADING INLAND THURSDAY NIGHT AND FRIDAY.
RISING SNOW LEVELS WILL LIMIT SNOW TO THE HIGHEST PEAKS. COLDER AIR
BEHIND THE FRONT WILL BRING ACCUMULATING SNOW SHOWERS FOR THE
CASCADES PASSES FRIDAY EVENING AND SATURDAY. MILD AND VERY WET
WEATHER ARRIVED THIS WEEKEND. THERE IS POTENTIAL FOR AN ATMOSPHERIC
RIVER AND ASSOCIATED HEAVY RAIN TO DEVELOP OVER THE AREA AFFECTING
RIVERS INTO NEXT WEEK.

&&

.SHORT TERM...TONIGHT THROUGH SATURDAY...A WEAK AND SPLITTING TROUGH
WILL SEND MOST OF ITS ENERGY SOUTH OF OUR AREA TONIGHT. WILL SEE
SHOWERS TAPER OFF OVERNIGHT AS HIGH PRESSURE BEGINS A TRANSIT ACROSS
THE AREA. WILL ALSO SEE CORRESPONDING SNOW LEVELS RISE ABOVE THE
PASSES AND GENERALLY LIMIT THE AMOUNT OF ACCUMULATIONS. THE RIDGE
AXIS QUICKLY PASSES EAST BY TOMORROW AFTERNOON LEADING TO A LARGELY
DRY DAY FOR THE INTERIOR.

ANOTHER MORE COHESIVE TROUGH AND FRONTAL SYSTEM WILL DIG OFFSHORE
WITH WARM FRONTAL RAIN TOUCHING THE COAST LATE FRIDAY AFTERNOON WITH
HEAVIER AMOUNTS BY EARLY FRIDAY EVENING. TIMING COULD BE EARLIER
DEPENDING ON MODEL OF CHOICE WITH THE GFS PERHAPS A COUPLE HOURS
FASTER THAN THE ECMWF AND THE NAM SLOWER YET. NAM TYPICALLY DOES NOT
HANDLE WARM PROCESS RAIN VERY WELL SO AM PUTTING LESS WEIGHT ON IT
TO START WITH. AS THE RAIN COMES IN...A COASTAL JET DEVELOPS
BRINGING FAIRLY GUSTY WINDS TO THE COAST AND COAST RANGE BUT NOTHING
TOO OUT OF THE ORDINARY. NOT ANTICIPATING ANY HIGHLIGHTS BUT
PROBABLY A RUN OF THE MILL WINDY COASTAL STORM. THE ASSOCIATED COLD
FRONT COME ASHORE AROUND 12Z FRIDAY MORNING AND CROSSES THE CASCADES
AROUND 17Z WITH COLDER AIR AND LOWERING SNOW LEVELS WITH AND MORE SO
BEHIND IT. PRECIPITATION TAPERS OFF AND BECOMES MORE SHOWERY IN
NATURE BEHIND THE FRONT. EXPECT LIGHT ACCUMULATING SNOW BEGINS AT
WILLAMETTE PASS AROUND DAY BREAK AND LOWERS TO NEAR GOVERNMENT PASS
LATER THAT MORNING. THE SNOW COMES TO BE TOO LITTLE...TOO LATE FOR
MUCH APPRECIABLE INCREASE IN THE SNOW PACK WITH PERHAPS A FEW INCHES
AT THE HIGHER PASSES AND LESS THAN AN INCH FOR GOVERNMENT CAMP.
HIGHER PEAKS COULD SEE UP TO A FOOT...HOWEVER. ANY OF THE MID
ELEVATION SNOW WILL BE RATHER SHORT-LIVED AS SNOW LEVELS IMMEDIATELY
BEGIN RISING IN ANTICIPATION OF THE PACIFIC STORM TRACK BECOMING
CENTERED OVER THE AREA.

MAIN ATTENTION THIS SHIFT HAS BEEN BE PLACED ON THE ATMOSPHERIC
RIVER EVENT SETTING UP TO AFFECT THE REGION THIS WEEKEND WITH
IMPACTS LASTING INTO NEXT WEEK. RAW GFS MODEL RUN ACCUMULATED QPF
AMOUNTS EXCEED 12 INCHES FOR PORTIONS OF THE CASCADES AND 10 INCHES
FOR THE COAST RANGE ENDING MONDAY MORNING. WILL SEE THE WARM RAINS
BEGIN AFFECTING THE COAST RANGE SATURDAY MORNING AND PUSH QUICKLY
INLAND TO THE CASCADES BY SATURDAY AFTERNOON. MOST OF THE HEAVY RAIN
OCCURS BEGINNING SATURDAY NIGHT. THERE WOULD BE DEEP WESTERLY FLOW
FROM THE SURFACE UP TO THE JET LEVEL THUS EXPECT THIS COULD BE AN
IDEAL OROGRAPHIC SITUATION TO EXTRACT A MAXIMUM AMOUNT OF RAIN FROM
WHATEVER COMES ASHORE. THERE IS GENERAL LARGE SCALE SUPPORT FROM THE
ECMWF ALBEIT WITH LESS QPF. PAST EXPERIENCE SHOWS FOLLOWING THE
HIGHER GFS QPF AMOUNTS IS STILL NOT ENOUGH AND THAT REALITY BRINGS
SIGNIFICANTLY MORE RAIN. ASSUMING THE CURRENT MODEL RUNS STAY
UNCHANGED IN THE FUTURE...WOULD EXPECT MULTIPLE MAINSTEM RIVERS
EXCEEDING FLOOD STAGE AS SOON AS SUNDAY EVENING.

HAVE ISSUED SOME OUTLOOK PRODUCTS TODAY LOOKING AHEAD TO FLOODING
POTENTIAL WITH THE CAVEAT THAT MODELS HAVE SHIFTED THE FOCUS FROM
NORTHERN WASHINGTON/BRITISH COLUMBIA SOUTH TO OUR AREA DURING THE
PAST 36 HOURS. ADDITIONAL SHIFTING IS EXPECTED AS WELL AS TIMING
DIFFERENCES. STAY TUNED AS THIS SITUATION EVOLVES OVER TIME.
/JBONK

.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY...MODELS MAINTAIN A
FLATTENED RIDGE OVER THE EASTERN PACIFIC FOR THE WEEKEND THROUGH
EARLY NEXT WEEK. WITH A NEARLY ZONAL JET AND ABUNDANT
MOISTURE...EXPECT PLENTY OF RAINFALL TO CONTINUE THROUGH SUNDAY. ON
MONDAY AND TUESDAY...SOME WEAK RIDGING MOVES OVER THE REGION BUT
SHOWERS LIKELY CONTINUE IN THE MOIST ONSHORE FLOW. AN UPPER TROUGH
DROPS SOUTH OVER THE REGION BY MIDWEEK WITH SOME RATHER COLD AIR AND
ADDITIONAL PRECIPITATION IN STORE. WHILE STILL SOME SIGNIFICANT
UNCERTAINTY EXISTS WITH RESPECT TO THE TIMING OF THE PRECIP VS COLD
AIR AND JUST HOW COLD THE AIR IS...IT DOES APPEAR THAT A SIGNIFICANT
SURGE OF COLD AIR MAY MOVE INTO THE REGION AND THEREFORE...DECREASED
TEMPERATURES ACCORDINGLY FOR THE TUE/WED PERIODS ACROSS THE REGION.
IT DOES APPEAR THAT SNOW LEVELS WILL DROP BELOW PASS LEVELS AT
LEAST...AND PERHAPS DOWN INTO THE FOOTHILL ELEVATIONS LATER
WEDNESDAY INTO THURSDAY. GIVEN THE UNCERTAINTY...THOSE PLANNING
HOLIDAY TRAVEL DURING THIS PERIOD SHOULD MONITOR THE FORECAST.
CULLEN

&&

.AVIATION...VFR CONDITIONS LIKELY TO CONTINUE THROUGH THIS
AFTERNOON. ONSHORE WINDS THIS EVENING BEHIND THE WEAK LOW MOVING
ONSHORE WILL ALLOW FOR CIGS AND VIS TO LOWER TO IFR TONIGHT WITH
THE DEVELOPMENT OF FOG/LOW STRATUS. THIS SHOULD HOLD ON THROUGH
THURSDAY MORNING...STARTING TO LIFT BACK TOWARD VFR AROUND 15 TO 18Z
THURSDAY AS WINDS START TO INCREASE OUT OF THE SOUTH. VFR WILL
CONTINUE THROUGH THURSDAY AFTERNOON...THOUGH LOW-LEVEL WIND SHEAR
WILL BE A CONCERN AT KTTD AND POSSIBLY KPDX AS 20 KT EASTERLY
WINDS FROM THE GORGE UNDERCUT INCREASING SOUTHERLY WINDS ALOFT.

KPDX AND APPROACHES...VFR CONDITIONS TO PERSIST THIS
EVENING. WEAK WINDS WILL COULD PROMOTE THE DEVELOPMENT OF FOG/LOW
STRATUS AFTER 06Z THURSDAY...DROPPING CIGS AND VIS TO IFR. THIS
SHOULD LIFT BACK TO VFR BY 18Z THURSDAY. -MCCOY

&&

.MARINE...WEAK LOW PRESSURE SYSTEM MOVING NORTHWARD ALONG THE
COAST HAS BROUGHT WINDS UP TO SCA CRITERIA THIS AFTERNOON IN OUR
SOUTHERN WATERS. THIS IS WEAKENING AND MOVING ONSHORE...WHICH
SHOULD ALLOW WINDS TO SUBSIDE FOR A BRIEF PERIOD THIS EVENING.
WINDS WILL BEGIN TO INCREASE ACROSS OUR WATERS THURSDAY MORNING
AHEAD OF A COLD FRONT WHICH WILL MOVE THROUGH OUR WATERS DURING
THE DAY THURSDAY. AHEAD OF THIS FRONT...WINDS LIKELY TO RAMP UP TO
GALE FORCE WITH A COASTAL JET FULLY DEVELOPED BY THURSDAY
EVENING AND PERSIST UNTIL THE FRONT MOVES ONSHORE EARLY FRIDAY
MORNING.

SEAS CURRENTLY AROUND 10-12 FT WILL DROP TO 9 FT LATER THIS
EVENING. SEAS WILL BEGIN TO BUILD AGAIN THURSDAY MORNING AS WINDS
INCREASE AHEAD OF THE COLD FRONT ON THURSDAY. SEAS EXPECTED TO
BUILD TO THE LOW-TO-MIDDLE TEENS THURSDAY EVENING...SUBSIDING TO
10 TO 12 FT EARLY FRIDAY MORNING. A DYNAMIC FETCH APPROACHES EARLY
FRIDAY...BRINGING A LARGE SWELL INTO OUR WATERS. THIS WILL CAUSE
SEAS TO RAPIDLY BUILD FRIDAY MORNING...REACHING 20 FT FRIDAY
EVENING. THE NEXT STRONG FRONT APPROACHES ON SATURDAY...WITH
GALES POSSIBLE...COULD BUILD SEAS ALREADY 15 TO 20 FEET...TO 20
TO 25 FT SATURDAY. -MCCOY

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 4 AM TO 1 PM PST THURSDAY
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 60 NM.

     GALE WARNING FROM 1 PM THURSDAY TO MIDNIGHT PST THURSDAY NIGHT
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 9 PM PST THIS
     EVENING FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR WINDS UNTIL 1 PM PST THURSDAY FOR
     COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 4 AM PST THURSDAY.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.




000
FXUS66 KPQR 172252
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
252 PM PST WED DEC 17 2014

.SYNOPSIS...WEAK LOW PRESSURE WILL CROSS THE AREA THIS EVENING WITH
SHOWERS LINGERING OVERNIGHT. EXPECT FAIRLY QUIET WEATHER TO START
THE DAY THURSDAY. A MORE ORGANIZED FRONT WILL BRING GUSTY WINDS TO
THE COAST WITH RAIN SPREADING INLAND THURSDAY NIGHT AND FRIDAY.
RISING SNOW LEVELS WILL LIMIT SNOW TO THE HIGHEST PEAKS. COLDER AIR
BEHIND THE FRONT WILL BRING ACCUMULATING SNOW SHOWERS FOR THE
CASCADES PASSES FRIDAY EVENING AND SATURDAY. MILD AND VERY WET
WEATHER ARRIVED THIS WEEKEND. THERE IS POTENTIAL FOR AN ATMOSPHERIC
RIVER AND ASSOCIATED HEAVY RAIN TO DEVELOP OVER THE AREA AFFECTING
RIVERS INTO NEXT WEEK.

&&

.SHORT TERM...TONIGHT THROUGH SATURDAY...A WEAK AND SPLITTING TROUGH
WILL SEND MOST OF ITS ENERGY SOUTH OF OUR AREA TONIGHT. WILL SEE
SHOWERS TAPER OFF OVERNIGHT AS HIGH PRESSURE BEGINS A TRANSIT ACROSS
THE AREA. WILL ALSO SEE CORRESPONDING SNOW LEVELS RISE ABOVE THE
PASSES AND GENERALLY LIMIT THE AMOUNT OF ACCUMULATIONS. THE RIDGE
AXIS QUICKLY PASSES EAST BY TOMORROW AFTERNOON LEADING TO A LARGELY
DRY DAY FOR THE INTERIOR.

ANOTHER MORE COHESIVE TROUGH AND FRONTAL SYSTEM WILL DIG OFFSHORE
WITH WARM FRONTAL RAIN TOUCHING THE COAST LATE FRIDAY AFTERNOON WITH
HEAVIER AMOUNTS BY EARLY FRIDAY EVENING. TIMING COULD BE EARLIER
DEPENDING ON MODEL OF CHOICE WITH THE GFS PERHAPS A COUPLE HOURS
FASTER THAN THE ECMWF AND THE NAM SLOWER YET. NAM TYPICALLY DOES NOT
HANDLE WARM PROCESS RAIN VERY WELL SO AM PUTTING LESS WEIGHT ON IT
TO START WITH. AS THE RAIN COMES IN...A COASTAL JET DEVELOPS
BRINGING FAIRLY GUSTY WINDS TO THE COAST AND COAST RANGE BUT NOTHING
TOO OUT OF THE ORDINARY. NOT ANTICIPATING ANY HIGHLIGHTS BUT
PROBABLY A RUN OF THE MILL WINDY COASTAL STORM. THE ASSOCIATED COLD
FRONT COME ASHORE AROUND 12Z FRIDAY MORNING AND CROSSES THE CASCADES
AROUND 17Z WITH COLDER AIR AND LOWERING SNOW LEVELS WITH AND MORE SO
BEHIND IT. PRECIPITATION TAPERS OFF AND BECOMES MORE SHOWERY IN
NATURE BEHIND THE FRONT. EXPECT LIGHT ACCUMULATING SNOW BEGINS AT
WILLAMETTE PASS AROUND DAY BREAK AND LOWERS TO NEAR GOVERNMENT PASS
LATER THAT MORNING. THE SNOW COMES TO BE TOO LITTLE...TOO LATE FOR
MUCH APPRECIABLE INCREASE IN THE SNOW PACK WITH PERHAPS A FEW INCHES
AT THE HIGHER PASSES AND LESS THAN AN INCH FOR GOVERNMENT CAMP.
HIGHER PEAKS COULD SEE UP TO A FOOT...HOWEVER. ANY OF THE MID
ELEVATION SNOW WILL BE RATHER SHORT-LIVED AS SNOW LEVELS IMMEDIATELY
BEGIN RISING IN ANTICIPATION OF THE PACIFIC STORM TRACK BECOMING
CENTERED OVER THE AREA.

MAIN ATTENTION THIS SHIFT HAS BEEN BE PLACED ON THE ATMOSPHERIC
RIVER EVENT SETTING UP TO AFFECT THE REGION THIS WEEKEND WITH
IMPACTS LASTING INTO NEXT WEEK. RAW GFS MODEL RUN ACCUMULATED QPF
AMOUNTS EXCEED 12 INCHES FOR PORTIONS OF THE CASCADES AND 10 INCHES
FOR THE COAST RANGE ENDING MONDAY MORNING. WILL SEE THE WARM RAINS
BEGIN AFFECTING THE COAST RANGE SATURDAY MORNING AND PUSH QUICKLY
INLAND TO THE CASCADES BY SATURDAY AFTERNOON. MOST OF THE HEAVY RAIN
OCCURS BEGINNING SATURDAY NIGHT. THERE WOULD BE DEEP WESTERLY FLOW
FROM THE SURFACE UP TO THE JET LEVEL THUS EXPECT THIS COULD BE AN
IDEAL OROGRAPHIC SITUATION TO EXTRACT A MAXIMUM AMOUNT OF RAIN FROM
WHATEVER COMES ASHORE. THERE IS GENERAL LARGE SCALE SUPPORT FROM THE
ECMWF ALBEIT WITH LESS QPF. PAST EXPERIENCE SHOWS FOLLOWING THE
HIGHER GFS QPF AMOUNTS IS STILL NOT ENOUGH AND THAT REALITY BRINGS
SIGNIFICANTLY MORE RAIN. ASSUMING THE CURRENT MODEL RUNS STAY
UNCHANGED IN THE FUTURE...WOULD EXPECT MULTIPLE MAINSTEM RIVERS
EXCEEDING FLOOD STAGE AS SOON AS SUNDAY EVENING.

HAVE ISSUED SOME OUTLOOK PRODUCTS TODAY LOOKING AHEAD TO FLOODING
POTENTIAL WITH THE CAVEAT THAT MODELS HAVE SHIFTED THE FOCUS FROM
NORTHERN WASHINGTON/BRITISH COLUMBIA SOUTH TO OUR AREA DURING THE
PAST 36 HOURS. ADDITIONAL SHIFTING IS EXPECTED AS WELL AS TIMING
DIFFERENCES. STAY TUNED AS THIS SITUATION EVOLVES OVER TIME.
/JBONK

.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY...MODELS MAINTAIN A
FLATTENED RIDGE OVER THE EASTERN PACIFIC FOR THE WEEKEND THROUGH
EARLY NEXT WEEK. WITH A NEARLY ZONAL JET AND ABUNDANT
MOISTURE...EXPECT PLENTY OF RAINFALL TO CONTINUE THROUGH SUNDAY. ON
MONDAY AND TUESDAY...SOME WEAK RIDGING MOVES OVER THE REGION BUT
SHOWERS LIKELY CONTINUE IN THE MOIST ONSHORE FLOW. AN UPPER TROUGH
DROPS SOUTH OVER THE REGION BY MIDWEEK WITH SOME RATHER COLD AIR AND
ADDITIONAL PRECIPITATION IN STORE. WHILE STILL SOME SIGNIFICANT
UNCERTAINTY EXISTS WITH RESPECT TO THE TIMING OF THE PRECIP VS COLD
AIR AND JUST HOW COLD THE AIR IS...IT DOES APPEAR THAT A SIGNIFICANT
SURGE OF COLD AIR MAY MOVE INTO THE REGION AND THEREFORE...DECREASED
TEMPERATURES ACCORDINGLY FOR THE TUE/WED PERIODS ACROSS THE REGION.
IT DOES APPEAR THAT SNOW LEVELS WILL DROP BELOW PASS LEVELS AT
LEAST...AND PERHAPS DOWN INTO THE FOOTHILL ELEVATIONS LATER
WEDNESDAY INTO THURSDAY. GIVEN THE UNCERTAINTY...THOSE PLANNING
HOLIDAY TRAVEL DURING THIS PERIOD SHOULD MONITOR THE FORECAST.
CULLEN

&&

.AVIATION...VFR CONDITIONS LIKELY TO CONTINUE THROUGH THIS
AFTERNOON. ONSHORE WINDS THIS EVENING BEHIND THE WEAK LOW MOVING
ONSHORE WILL ALLOW FOR CIGS AND VIS TO LOWER TO IFR TONIGHT WITH
THE DEVELOPMENT OF FOG/LOW STRATUS. THIS SHOULD HOLD ON THROUGH
THURSDAY MORNING...STARTING TO LIFT BACK TOWARD VFR AROUND 15 TO 18Z
THURSDAY AS WINDS START TO INCREASE OUT OF THE SOUTH. VFR WILL
CONTINUE THROUGH THURSDAY AFTERNOON...THOUGH LOW-LEVEL WIND SHEAR
WILL BE A CONCERN AT KTTD AND POSSIBLY KPDX AS 20 KT EASTERLY
WINDS FROM THE GORGE UNDERCUT INCREASING SOUTHERLY WINDS ALOFT.

KPDX AND APPROACHES...VFR CONDITIONS TO PERSIST THIS
EVENING. WEAK WINDS WILL COULD PROMOTE THE DEVELOPMENT OF FOG/LOW
STRATUS AFTER 06Z THURSDAY...DROPPING CIGS AND VIS TO IFR. THIS
SHOULD LIFT BACK TO VFR BY 18Z THURSDAY. -MCCOY

&&

.MARINE...WEAK LOW PRESSURE SYSTEM MOVING NORTHWARD ALONG THE
COAST HAS BROUGHT WINDS UP TO SCA CRITERIA THIS AFTERNOON IN OUR
SOUTHERN WATERS. THIS IS WEAKENING AND MOVING ONSHORE...WHICH
SHOULD ALLOW WINDS TO SUBSIDE FOR A BRIEF PERIOD THIS EVENING.
WINDS WILL BEGIN TO INCREASE ACROSS OUR WATERS THURSDAY MORNING
AHEAD OF A COLD FRONT WHICH WILL MOVE THROUGH OUR WATERS DURING
THE DAY THURSDAY. AHEAD OF THIS FRONT...WINDS LIKELY TO RAMP UP TO
GALE FORCE WITH A COASTAL JET FULLY DEVELOPED BY THURSDAY
EVENING AND PERSIST UNTIL THE FRONT MOVES ONSHORE EARLY FRIDAY
MORNING.

SEAS CURRENTLY AROUND 10-12 FT WILL DROP TO 9 FT LATER THIS
EVENING. SEAS WILL BEGIN TO BUILD AGAIN THURSDAY MORNING AS WINDS
INCREASE AHEAD OF THE COLD FRONT ON THURSDAY. SEAS EXPECTED TO
BUILD TO THE LOW-TO-MIDDLE TEENS THURSDAY EVENING...SUBSIDING TO
10 TO 12 FT EARLY FRIDAY MORNING. A DYNAMIC FETCH APPROACHES EARLY
FRIDAY...BRINGING A LARGE SWELL INTO OUR WATERS. THIS WILL CAUSE
SEAS TO RAPIDLY BUILD FRIDAY MORNING...REACHING 20 FT FRIDAY
EVENING. THE NEXT STRONG FRONT APPROACHES ON SATURDAY...WITH
GALES POSSIBLE...COULD BUILD SEAS ALREADY 15 TO 20 FEET...TO 20
TO 25 FT SATURDAY. -MCCOY

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 4 AM TO 1 PM PST THURSDAY
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 60 NM.

     GALE WARNING FROM 1 PM THURSDAY TO MIDNIGHT PST THURSDAY NIGHT
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 9 PM PST THIS
     EVENING FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR WINDS UNTIL 1 PM PST THURSDAY FOR
     COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 4 AM PST THURSDAY.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.




000
FXUS66 KOTX 172252
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
252 PM PST WED DEC 17 2014

.SYNOPSIS...
A more active weather pattern will continue through the end of the
week with periods of light snow in the mountains...and rain or
snow in the valleys. Lower elevations from Interstate 90 south
will see mainly rain...while areas in the Cascades and near the
Canadian border will remain mainly snow. A much stronger weather
system over the weekend will usher in warmer temperatures with
sharply rising snow levels...as well as the potential for windy
conditions.

&&

.DISCUSSION...

Tonight and Tomorrow...A number of small weak disturbances running
across Eastern Washington and Northern Idaho through tonight and
tomorrow. They are very difficult to pick out in some of the
models as there is too much clutter in the flow associated with
the weakening baroclinic band upon where these disturbances are
located near that is currently passing through the area. They
haven`t been showing up too well in the radar either as they have
been far enough away for most of the day for the base elevation
beam to get a return on as well. Best bet to find these features
has been the IR satellite imagery on a fast rock and picking out
the small scale rotation and cloud top cooling. One such feature
is moving northeast this afternoon and is causing precipitation
just east of Moses Lake up to Omak and some points to the north
and east. A second feature, appearing to almost be a southern part
of the splitting/weakening baroclinic band has brought light rain
to Lewiston. All of these disturbances translate to the Northeast
and East at varying times tonight and tomorrow and as such the
pops and QPF show a general favoring of locations to the North and
East (including locations near Spokane down to Pullman) to receive
some precipitation but as expected the amounts are not too
significant...still it doesn`t take too much liquid to pool on
pavement that in turn cools overnight to allow for slick
conditions in spots similar to what occurred this morning.
/Pelatti

Thursday night through Sunday...An active weather pattern is
expected especially over the weekend with two systems to impacts
the Inland Northwest during this forecast period.

Thursday night/Friday: A large upper low seen on Infrared
Satellite Imagery in the Gulf of Alaska will drop southeast
sending a cold front across the area. The timing of the front
tracks into Central Washington Thursday night during the overnight
hours...reaching Eastern Washington and North Idaho Friday
morning. A north-south oriented jet parallel to the front and
southerly low/mid level flow will minimize downslope flow with all
areas likely to receive some precipitation. Inspection of model
soundings suggest this to be a mainly valley rain or rain/snow
mix...with snow in the mountains. 850mb winds backing to the south
will aid in bring up warmer air from the south. However a wedge of
cooler air trapped along the East Slopes of the Cascades will
result in lower snow levels over North Central Washington with the
potential for 2-3 inches of snow accumulation above 1000-1500
feet. This includes the Methow Valley, Plain, Waterville Plateau,
higher portions of Omak, and Republic. The Wenatchee area and
lower portions of the Okanogan and Columbia River valleys are
expected to see mainly a rain/snow mix or wet non-accumulating
snow. The mountains will generally see 2-5 inches of snow with the
Cascades seeing the highest amounts.

Saturday through Sunday...A much stronger system is expected this
weekend bringing a wide variety of expected weather. The models
continue to show an atmospheric river as a subtropical moisture
fetch becomes aimed at the area. The leading edge of this moisture
will enter on Saturday in the form of a warm front. Strong
isentropic lift will result in the development of widespread
rain and snow. 850mb winds backing to the south-southeast will
favor upslope flow into the northern mountains, with cooler air
remaining banked up into the Cascades, Okanogan Valley, and
Okanogan Highlands. Models suggest the potential for moderate to
locally heavy snow accumulations in these areas along and ahead of
the warm front before snow levels rise from south to north
Saturday night into Sunday morning. Snow levels will be fast to
rise from Interstate 90 south with precip expected to fall as
mainly valley rain and mountain snow. The valleys north of Spokane
such as Colville, Metaline Falls, Priest Lake, and Bonners Ferry
may start off as snow on Saturday with light accumulations...before
changing to rain Saturday night. As the warmer air aloft pokes
into the Cascades Saturday night...the valleys will likely have a
hard time mixing out with freezing rain possible especially south
of Lake Chelan in places like Plain and Leavenworth.

On Sunday the atmospheric river shifts south near the
Washington/Oregon border with strong westerly flow over the area.
This will lead to a strong rain shadow east of the Cascades with
precipitation likely confined mainly to the Cascade crest, Idaho
Panhandle, and southeast Washington. 850mb winds of 25-35 kts and
possible sun breaks across the Columbia Basin...and 850mb temps of
3-6C could lead to very mild temperatures along with breezy to
windy conditions. For now went a bit above MOS guidance which
usually does not go warm enough in these situations. JW

Sunday Nt through Christmas Eve: Following the passage of the windy
and wet short-wave trough that will move through broad upper
ridging Sunday Nt, what`s left of a stalled cold frontal boundary
will remain over Nrn Oregon and extreme Srn Wa Tues and keep the
threat of pcpn in the fcst for the Lewiston area as well as the Camas
Prairie. Where this front stalls will be critical as far as the
Christmas Eve fcst, because it is this boundary that will combine
with a significant short-wave trough and vort max moving into the
region as it translates SE down the BC coast. Deep cyclogenesis is
fcst by most model guidance over Ern Oregon Wednesday as the flow
backs and increases lift over the aforementioned boundary. As
pressure gradients increase, cold air will then begin to move into
Ern Wa from Srn Bc. Though it`s unusual even to see modest amnts
of agreement among models as to the placement of this deep low 7
days out, there still are enough differences how far south the
low will track that still make our level of confidence low as to where
potentially heavy snow bands may set up Christmas Eve. The trend,
however, has been slightly south which would keep the higher snow
threat out of Nrn Wa. Stay tuned... bz

&&

.AVIATION...
18Z TAFS: Weak disturbances drifting northeast and over the
aviation over the next 24 hours keep the forecast somewhat
cluttered with mentions of both rain and snow at times which
produce IFR/LIFR ceilings and visibilities. Some fog will
occasionally impact locations as well. Precipitation still on the
light side with the higher amounts primarily near the East Slopes
of the North Cascades out to the Waterville Plateau and points to
the north/northeast. The KGEG area will be more MVFR most of the
time as the precipitation will be light and likely to be rain.
/Pelatti

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        32  37  33  39  31  40 /  50  30  40  90  10  70
Coeur d`Alene  33  38  32  39  32  39 /  60  60  20 100  20  70
Pullman        33  43  34  42  32  43 /  50  40  40  90  10  70
Lewiston       35  45  36  46  33  47 /  40  30  20  70  10  40
Colville       32  37  34  38  32  38 /  60  30  60 100  10  80
Sandpoint      32  37  32  36  31  38 /  60  60  30 100  40  60
Kellogg        32  38  32  36  31  36 /  70  70  20 100  40  60
Moses Lake     29  39  36  42  30  39 /  20  10  70  70  10  70
Wenatchee      31  37  33  40  30  34 /  30  10  70  60  10  70
Omak           27  34  32  37  30  33 /  40  10  80  80  10  80

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 172252
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
252 PM PST WED DEC 17 2014

.SYNOPSIS...
A more active weather pattern will continue through the end of the
week with periods of light snow in the mountains...and rain or
snow in the valleys. Lower elevations from Interstate 90 south
will see mainly rain...while areas in the Cascades and near the
Canadian border will remain mainly snow. A much stronger weather
system over the weekend will usher in warmer temperatures with
sharply rising snow levels...as well as the potential for windy
conditions.

&&

.DISCUSSION...

Tonight and Tomorrow...A number of small weak disturbances running
across Eastern Washington and Northern Idaho through tonight and
tomorrow. They are very difficult to pick out in some of the
models as there is too much clutter in the flow associated with
the weakening baroclinic band upon where these disturbances are
located near that is currently passing through the area. They
haven`t been showing up too well in the radar either as they have
been far enough away for most of the day for the base elevation
beam to get a return on as well. Best bet to find these features
has been the IR satellite imagery on a fast rock and picking out
the small scale rotation and cloud top cooling. One such feature
is moving northeast this afternoon and is causing precipitation
just east of Moses Lake up to Omak and some points to the north
and east. A second feature, appearing to almost be a southern part
of the splitting/weakening baroclinic band has brought light rain
to Lewiston. All of these disturbances translate to the Northeast
and East at varying times tonight and tomorrow and as such the
pops and QPF show a general favoring of locations to the North and
East (including locations near Spokane down to Pullman) to receive
some precipitation but as expected the amounts are not too
significant...still it doesn`t take too much liquid to pool on
pavement that in turn cools overnight to allow for slick
conditions in spots similar to what occurred this morning.
/Pelatti

Thursday night through Sunday...An active weather pattern is
expected especially over the weekend with two systems to impacts
the Inland Northwest during this forecast period.

Thursday night/Friday: A large upper low seen on Infrared
Satellite Imagery in the Gulf of Alaska will drop southeast
sending a cold front across the area. The timing of the front
tracks into Central Washington Thursday night during the overnight
hours...reaching Eastern Washington and North Idaho Friday
morning. A north-south oriented jet parallel to the front and
southerly low/mid level flow will minimize downslope flow with all
areas likely to receive some precipitation. Inspection of model
soundings suggest this to be a mainly valley rain or rain/snow
mix...with snow in the mountains. 850mb winds backing to the south
will aid in bring up warmer air from the south. However a wedge of
cooler air trapped along the East Slopes of the Cascades will
result in lower snow levels over North Central Washington with the
potential for 2-3 inches of snow accumulation above 1000-1500
feet. This includes the Methow Valley, Plain, Waterville Plateau,
higher portions of Omak, and Republic. The Wenatchee area and
lower portions of the Okanogan and Columbia River valleys are
expected to see mainly a rain/snow mix or wet non-accumulating
snow. The mountains will generally see 2-5 inches of snow with the
Cascades seeing the highest amounts.

Saturday through Sunday...A much stronger system is expected this
weekend bringing a wide variety of expected weather. The models
continue to show an atmospheric river as a subtropical moisture
fetch becomes aimed at the area. The leading edge of this moisture
will enter on Saturday in the form of a warm front. Strong
isentropic lift will result in the development of widespread
rain and snow. 850mb winds backing to the south-southeast will
favor upslope flow into the northern mountains, with cooler air
remaining banked up into the Cascades, Okanogan Valley, and
Okanogan Highlands. Models suggest the potential for moderate to
locally heavy snow accumulations in these areas along and ahead of
the warm front before snow levels rise from south to north
Saturday night into Sunday morning. Snow levels will be fast to
rise from Interstate 90 south with precip expected to fall as
mainly valley rain and mountain snow. The valleys north of Spokane
such as Colville, Metaline Falls, Priest Lake, and Bonners Ferry
may start off as snow on Saturday with light accumulations...before
changing to rain Saturday night. As the warmer air aloft pokes
into the Cascades Saturday night...the valleys will likely have a
hard time mixing out with freezing rain possible especially south
of Lake Chelan in places like Plain and Leavenworth.

On Sunday the atmospheric river shifts south near the
Washington/Oregon border with strong westerly flow over the area.
This will lead to a strong rain shadow east of the Cascades with
precipitation likely confined mainly to the Cascade crest, Idaho
Panhandle, and southeast Washington. 850mb winds of 25-35 kts and
possible sun breaks across the Columbia Basin...and 850mb temps of
3-6C could lead to very mild temperatures along with breezy to
windy conditions. For now went a bit above MOS guidance which
usually does not go warm enough in these situations. JW

Sunday Nt through Christmas Eve: Following the passage of the windy
and wet short-wave trough that will move through broad upper
ridging Sunday Nt, what`s left of a stalled cold frontal boundary
will remain over Nrn Oregon and extreme Srn Wa Tues and keep the
threat of pcpn in the fcst for the Lewiston area as well as the Camas
Prairie. Where this front stalls will be critical as far as the
Christmas Eve fcst, because it is this boundary that will combine
with a significant short-wave trough and vort max moving into the
region as it translates SE down the BC coast. Deep cyclogenesis is
fcst by most model guidance over Ern Oregon Wednesday as the flow
backs and increases lift over the aforementioned boundary. As
pressure gradients increase, cold air will then begin to move into
Ern Wa from Srn Bc. Though it`s unusual even to see modest amnts
of agreement among models as to the placement of this deep low 7
days out, there still are enough differences how far south the
low will track that still make our level of confidence low as to where
potentially heavy snow bands may set up Christmas Eve. The trend,
however, has been slightly south which would keep the higher snow
threat out of Nrn Wa. Stay tuned... bz

&&

.AVIATION...
18Z TAFS: Weak disturbances drifting northeast and over the
aviation over the next 24 hours keep the forecast somewhat
cluttered with mentions of both rain and snow at times which
produce IFR/LIFR ceilings and visibilities. Some fog will
occasionally impact locations as well. Precipitation still on the
light side with the higher amounts primarily near the East Slopes
of the North Cascades out to the Waterville Plateau and points to
the north/northeast. The KGEG area will be more MVFR most of the
time as the precipitation will be light and likely to be rain.
/Pelatti

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        32  37  33  39  31  40 /  50  30  40  90  10  70
Coeur d`Alene  33  38  32  39  32  39 /  60  60  20 100  20  70
Pullman        33  43  34  42  32  43 /  50  40  40  90  10  70
Lewiston       35  45  36  46  33  47 /  40  30  20  70  10  40
Colville       32  37  34  38  32  38 /  60  30  60 100  10  80
Sandpoint      32  37  32  36  31  38 /  60  60  30 100  40  60
Kellogg        32  38  32  36  31  36 /  70  70  20 100  40  60
Moses Lake     29  39  36  42  30  39 /  20  10  70  70  10  70
Wenatchee      31  37  33  40  30  34 /  30  10  70  60  10  70
Omak           27  34  32  37  30  33 /  40  10  80  80  10  80

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KPQR 172252
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
252 PM PST WED DEC 17 2014

.SYNOPSIS...WEAK LOW PRESSURE WILL CROSS THE AREA THIS EVENING WITH
SHOWERS LINGERING OVERNIGHT. EXPECT FAIRLY QUIET WEATHER TO START
THE DAY THURSDAY. A MORE ORGANIZED FRONT WILL BRING GUSTY WINDS TO
THE COAST WITH RAIN SPREADING INLAND THURSDAY NIGHT AND FRIDAY.
RISING SNOW LEVELS WILL LIMIT SNOW TO THE HIGHEST PEAKS. COLDER AIR
BEHIND THE FRONT WILL BRING ACCUMULATING SNOW SHOWERS FOR THE
CASCADES PASSES FRIDAY EVENING AND SATURDAY. MILD AND VERY WET
WEATHER ARRIVED THIS WEEKEND. THERE IS POTENTIAL FOR AN ATMOSPHERIC
RIVER AND ASSOCIATED HEAVY RAIN TO DEVELOP OVER THE AREA AFFECTING
RIVERS INTO NEXT WEEK.

&&

.SHORT TERM...TONIGHT THROUGH SATURDAY...A WEAK AND SPLITTING TROUGH
WILL SEND MOST OF ITS ENERGY SOUTH OF OUR AREA TONIGHT. WILL SEE
SHOWERS TAPER OFF OVERNIGHT AS HIGH PRESSURE BEGINS A TRANSIT ACROSS
THE AREA. WILL ALSO SEE CORRESPONDING SNOW LEVELS RISE ABOVE THE
PASSES AND GENERALLY LIMIT THE AMOUNT OF ACCUMULATIONS. THE RIDGE
AXIS QUICKLY PASSES EAST BY TOMORROW AFTERNOON LEADING TO A LARGELY
DRY DAY FOR THE INTERIOR.

ANOTHER MORE COHESIVE TROUGH AND FRONTAL SYSTEM WILL DIG OFFSHORE
WITH WARM FRONTAL RAIN TOUCHING THE COAST LATE FRIDAY AFTERNOON WITH
HEAVIER AMOUNTS BY EARLY FRIDAY EVENING. TIMING COULD BE EARLIER
DEPENDING ON MODEL OF CHOICE WITH THE GFS PERHAPS A COUPLE HOURS
FASTER THAN THE ECMWF AND THE NAM SLOWER YET. NAM TYPICALLY DOES NOT
HANDLE WARM PROCESS RAIN VERY WELL SO AM PUTTING LESS WEIGHT ON IT
TO START WITH. AS THE RAIN COMES IN...A COASTAL JET DEVELOPS
BRINGING FAIRLY GUSTY WINDS TO THE COAST AND COAST RANGE BUT NOTHING
TOO OUT OF THE ORDINARY. NOT ANTICIPATING ANY HIGHLIGHTS BUT
PROBABLY A RUN OF THE MILL WINDY COASTAL STORM. THE ASSOCIATED COLD
FRONT COME ASHORE AROUND 12Z FRIDAY MORNING AND CROSSES THE CASCADES
AROUND 17Z WITH COLDER AIR AND LOWERING SNOW LEVELS WITH AND MORE SO
BEHIND IT. PRECIPITATION TAPERS OFF AND BECOMES MORE SHOWERY IN
NATURE BEHIND THE FRONT. EXPECT LIGHT ACCUMULATING SNOW BEGINS AT
WILLAMETTE PASS AROUND DAY BREAK AND LOWERS TO NEAR GOVERNMENT PASS
LATER THAT MORNING. THE SNOW COMES TO BE TOO LITTLE...TOO LATE FOR
MUCH APPRECIABLE INCREASE IN THE SNOW PACK WITH PERHAPS A FEW INCHES
AT THE HIGHER PASSES AND LESS THAN AN INCH FOR GOVERNMENT CAMP.
HIGHER PEAKS COULD SEE UP TO A FOOT...HOWEVER. ANY OF THE MID
ELEVATION SNOW WILL BE RATHER SHORT-LIVED AS SNOW LEVELS IMMEDIATELY
BEGIN RISING IN ANTICIPATION OF THE PACIFIC STORM TRACK BECOMING
CENTERED OVER THE AREA.

MAIN ATTENTION THIS SHIFT HAS BEEN BE PLACED ON THE ATMOSPHERIC
RIVER EVENT SETTING UP TO AFFECT THE REGION THIS WEEKEND WITH
IMPACTS LASTING INTO NEXT WEEK. RAW GFS MODEL RUN ACCUMULATED QPF
AMOUNTS EXCEED 12 INCHES FOR PORTIONS OF THE CASCADES AND 10 INCHES
FOR THE COAST RANGE ENDING MONDAY MORNING. WILL SEE THE WARM RAINS
BEGIN AFFECTING THE COAST RANGE SATURDAY MORNING AND PUSH QUICKLY
INLAND TO THE CASCADES BY SATURDAY AFTERNOON. MOST OF THE HEAVY RAIN
OCCURS BEGINNING SATURDAY NIGHT. THERE WOULD BE DEEP WESTERLY FLOW
FROM THE SURFACE UP TO THE JET LEVEL THUS EXPECT THIS COULD BE AN
IDEAL OROGRAPHIC SITUATION TO EXTRACT A MAXIMUM AMOUNT OF RAIN FROM
WHATEVER COMES ASHORE. THERE IS GENERAL LARGE SCALE SUPPORT FROM THE
ECMWF ALBEIT WITH LESS QPF. PAST EXPERIENCE SHOWS FOLLOWING THE
HIGHER GFS QPF AMOUNTS IS STILL NOT ENOUGH AND THAT REALITY BRINGS
SIGNIFICANTLY MORE RAIN. ASSUMING THE CURRENT MODEL RUNS STAY
UNCHANGED IN THE FUTURE...WOULD EXPECT MULTIPLE MAINSTEM RIVERS
EXCEEDING FLOOD STAGE AS SOON AS SUNDAY EVENING.

HAVE ISSUED SOME OUTLOOK PRODUCTS TODAY LOOKING AHEAD TO FLOODING
POTENTIAL WITH THE CAVEAT THAT MODELS HAVE SHIFTED THE FOCUS FROM
NORTHERN WASHINGTON/BRITISH COLUMBIA SOUTH TO OUR AREA DURING THE
PAST 36 HOURS. ADDITIONAL SHIFTING IS EXPECTED AS WELL AS TIMING
DIFFERENCES. STAY TUNED AS THIS SITUATION EVOLVES OVER TIME.
/JBONK

.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY...MODELS MAINTAIN A
FLATTENED RIDGE OVER THE EASTERN PACIFIC FOR THE WEEKEND THROUGH
EARLY NEXT WEEK. WITH A NEARLY ZONAL JET AND ABUNDANT
MOISTURE...EXPECT PLENTY OF RAINFALL TO CONTINUE THROUGH SUNDAY. ON
MONDAY AND TUESDAY...SOME WEAK RIDGING MOVES OVER THE REGION BUT
SHOWERS LIKELY CONTINUE IN THE MOIST ONSHORE FLOW. AN UPPER TROUGH
DROPS SOUTH OVER THE REGION BY MIDWEEK WITH SOME RATHER COLD AIR AND
ADDITIONAL PRECIPITATION IN STORE. WHILE STILL SOME SIGNIFICANT
UNCERTAINTY EXISTS WITH RESPECT TO THE TIMING OF THE PRECIP VS COLD
AIR AND JUST HOW COLD THE AIR IS...IT DOES APPEAR THAT A SIGNIFICANT
SURGE OF COLD AIR MAY MOVE INTO THE REGION AND THEREFORE...DECREASED
TEMPERATURES ACCORDINGLY FOR THE TUE/WED PERIODS ACROSS THE REGION.
IT DOES APPEAR THAT SNOW LEVELS WILL DROP BELOW PASS LEVELS AT
LEAST...AND PERHAPS DOWN INTO THE FOOTHILL ELEVATIONS LATER
WEDNESDAY INTO THURSDAY. GIVEN THE UNCERTAINTY...THOSE PLANNING
HOLIDAY TRAVEL DURING THIS PERIOD SHOULD MONITOR THE FORECAST.
CULLEN

&&

.AVIATION...VFR CONDITIONS LIKELY TO CONTINUE THROUGH THIS
AFTERNOON. ONSHORE WINDS THIS EVENING BEHIND THE WEAK LOW MOVING
ONSHORE WILL ALLOW FOR CIGS AND VIS TO LOWER TO IFR TONIGHT WITH
THE DEVELOPMENT OF FOG/LOW STRATUS. THIS SHOULD HOLD ON THROUGH
THURSDAY MORNING...STARTING TO LIFT BACK TOWARD VFR AROUND 15 TO 18Z
THURSDAY AS WINDS START TO INCREASE OUT OF THE SOUTH. VFR WILL
CONTINUE THROUGH THURSDAY AFTERNOON...THOUGH LOW-LEVEL WIND SHEAR
WILL BE A CONCERN AT KTTD AND POSSIBLY KPDX AS 20 KT EASTERLY
WINDS FROM THE GORGE UNDERCUT INCREASING SOUTHERLY WINDS ALOFT.

KPDX AND APPROACHES...VFR CONDITIONS TO PERSIST THIS
EVENING. WEAK WINDS WILL COULD PROMOTE THE DEVELOPMENT OF FOG/LOW
STRATUS AFTER 06Z THURSDAY...DROPPING CIGS AND VIS TO IFR. THIS
SHOULD LIFT BACK TO VFR BY 18Z THURSDAY. -MCCOY

&&

.MARINE...WEAK LOW PRESSURE SYSTEM MOVING NORTHWARD ALONG THE
COAST HAS BROUGHT WINDS UP TO SCA CRITERIA THIS AFTERNOON IN OUR
SOUTHERN WATERS. THIS IS WEAKENING AND MOVING ONSHORE...WHICH
SHOULD ALLOW WINDS TO SUBSIDE FOR A BRIEF PERIOD THIS EVENING.
WINDS WILL BEGIN TO INCREASE ACROSS OUR WATERS THURSDAY MORNING
AHEAD OF A COLD FRONT WHICH WILL MOVE THROUGH OUR WATERS DURING
THE DAY THURSDAY. AHEAD OF THIS FRONT...WINDS LIKELY TO RAMP UP TO
GALE FORCE WITH A COASTAL JET FULLY DEVELOPED BY THURSDAY
EVENING AND PERSIST UNTIL THE FRONT MOVES ONSHORE EARLY FRIDAY
MORNING.

SEAS CURRENTLY AROUND 10-12 FT WILL DROP TO 9 FT LATER THIS
EVENING. SEAS WILL BEGIN TO BUILD AGAIN THURSDAY MORNING AS WINDS
INCREASE AHEAD OF THE COLD FRONT ON THURSDAY. SEAS EXPECTED TO
BUILD TO THE LOW-TO-MIDDLE TEENS THURSDAY EVENING...SUBSIDING TO
10 TO 12 FT EARLY FRIDAY MORNING. A DYNAMIC FETCH APPROACHES EARLY
FRIDAY...BRINGING A LARGE SWELL INTO OUR WATERS. THIS WILL CAUSE
SEAS TO RAPIDLY BUILD FRIDAY MORNING...REACHING 20 FT FRIDAY
EVENING. THE NEXT STRONG FRONT APPROACHES ON SATURDAY...WITH
GALES POSSIBLE...COULD BUILD SEAS ALREADY 15 TO 20 FEET...TO 20
TO 25 FT SATURDAY. -MCCOY

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 4 AM TO 1 PM PST THURSDAY
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 60 NM.

     GALE WARNING FROM 1 PM THURSDAY TO MIDNIGHT PST THURSDAY NIGHT
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 9 PM PST THIS
     EVENING FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR WINDS UNTIL 1 PM PST THURSDAY FOR
     COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 4 AM PST THURSDAY.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.




000
FXUS66 KPQR 172252
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
252 PM PST WED DEC 17 2014

.SYNOPSIS...WEAK LOW PRESSURE WILL CROSS THE AREA THIS EVENING WITH
SHOWERS LINGERING OVERNIGHT. EXPECT FAIRLY QUIET WEATHER TO START
THE DAY THURSDAY. A MORE ORGANIZED FRONT WILL BRING GUSTY WINDS TO
THE COAST WITH RAIN SPREADING INLAND THURSDAY NIGHT AND FRIDAY.
RISING SNOW LEVELS WILL LIMIT SNOW TO THE HIGHEST PEAKS. COLDER AIR
BEHIND THE FRONT WILL BRING ACCUMULATING SNOW SHOWERS FOR THE
CASCADES PASSES FRIDAY EVENING AND SATURDAY. MILD AND VERY WET
WEATHER ARRIVED THIS WEEKEND. THERE IS POTENTIAL FOR AN ATMOSPHERIC
RIVER AND ASSOCIATED HEAVY RAIN TO DEVELOP OVER THE AREA AFFECTING
RIVERS INTO NEXT WEEK.

&&

.SHORT TERM...TONIGHT THROUGH SATURDAY...A WEAK AND SPLITTING TROUGH
WILL SEND MOST OF ITS ENERGY SOUTH OF OUR AREA TONIGHT. WILL SEE
SHOWERS TAPER OFF OVERNIGHT AS HIGH PRESSURE BEGINS A TRANSIT ACROSS
THE AREA. WILL ALSO SEE CORRESPONDING SNOW LEVELS RISE ABOVE THE
PASSES AND GENERALLY LIMIT THE AMOUNT OF ACCUMULATIONS. THE RIDGE
AXIS QUICKLY PASSES EAST BY TOMORROW AFTERNOON LEADING TO A LARGELY
DRY DAY FOR THE INTERIOR.

ANOTHER MORE COHESIVE TROUGH AND FRONTAL SYSTEM WILL DIG OFFSHORE
WITH WARM FRONTAL RAIN TOUCHING THE COAST LATE FRIDAY AFTERNOON WITH
HEAVIER AMOUNTS BY EARLY FRIDAY EVENING. TIMING COULD BE EARLIER
DEPENDING ON MODEL OF CHOICE WITH THE GFS PERHAPS A COUPLE HOURS
FASTER THAN THE ECMWF AND THE NAM SLOWER YET. NAM TYPICALLY DOES NOT
HANDLE WARM PROCESS RAIN VERY WELL SO AM PUTTING LESS WEIGHT ON IT
TO START WITH. AS THE RAIN COMES IN...A COASTAL JET DEVELOPS
BRINGING FAIRLY GUSTY WINDS TO THE COAST AND COAST RANGE BUT NOTHING
TOO OUT OF THE ORDINARY. NOT ANTICIPATING ANY HIGHLIGHTS BUT
PROBABLY A RUN OF THE MILL WINDY COASTAL STORM. THE ASSOCIATED COLD
FRONT COME ASHORE AROUND 12Z FRIDAY MORNING AND CROSSES THE CASCADES
AROUND 17Z WITH COLDER AIR AND LOWERING SNOW LEVELS WITH AND MORE SO
BEHIND IT. PRECIPITATION TAPERS OFF AND BECOMES MORE SHOWERY IN
NATURE BEHIND THE FRONT. EXPECT LIGHT ACCUMULATING SNOW BEGINS AT
WILLAMETTE PASS AROUND DAY BREAK AND LOWERS TO NEAR GOVERNMENT PASS
LATER THAT MORNING. THE SNOW COMES TO BE TOO LITTLE...TOO LATE FOR
MUCH APPRECIABLE INCREASE IN THE SNOW PACK WITH PERHAPS A FEW INCHES
AT THE HIGHER PASSES AND LESS THAN AN INCH FOR GOVERNMENT CAMP.
HIGHER PEAKS COULD SEE UP TO A FOOT...HOWEVER. ANY OF THE MID
ELEVATION SNOW WILL BE RATHER SHORT-LIVED AS SNOW LEVELS IMMEDIATELY
BEGIN RISING IN ANTICIPATION OF THE PACIFIC STORM TRACK BECOMING
CENTERED OVER THE AREA.

MAIN ATTENTION THIS SHIFT HAS BEEN BE PLACED ON THE ATMOSPHERIC
RIVER EVENT SETTING UP TO AFFECT THE REGION THIS WEEKEND WITH
IMPACTS LASTING INTO NEXT WEEK. RAW GFS MODEL RUN ACCUMULATED QPF
AMOUNTS EXCEED 12 INCHES FOR PORTIONS OF THE CASCADES AND 10 INCHES
FOR THE COAST RANGE ENDING MONDAY MORNING. WILL SEE THE WARM RAINS
BEGIN AFFECTING THE COAST RANGE SATURDAY MORNING AND PUSH QUICKLY
INLAND TO THE CASCADES BY SATURDAY AFTERNOON. MOST OF THE HEAVY RAIN
OCCURS BEGINNING SATURDAY NIGHT. THERE WOULD BE DEEP WESTERLY FLOW
FROM THE SURFACE UP TO THE JET LEVEL THUS EXPECT THIS COULD BE AN
IDEAL OROGRAPHIC SITUATION TO EXTRACT A MAXIMUM AMOUNT OF RAIN FROM
WHATEVER COMES ASHORE. THERE IS GENERAL LARGE SCALE SUPPORT FROM THE
ECMWF ALBEIT WITH LESS QPF. PAST EXPERIENCE SHOWS FOLLOWING THE
HIGHER GFS QPF AMOUNTS IS STILL NOT ENOUGH AND THAT REALITY BRINGS
SIGNIFICANTLY MORE RAIN. ASSUMING THE CURRENT MODEL RUNS STAY
UNCHANGED IN THE FUTURE...WOULD EXPECT MULTIPLE MAINSTEM RIVERS
EXCEEDING FLOOD STAGE AS SOON AS SUNDAY EVENING.

HAVE ISSUED SOME OUTLOOK PRODUCTS TODAY LOOKING AHEAD TO FLOODING
POTENTIAL WITH THE CAVEAT THAT MODELS HAVE SHIFTED THE FOCUS FROM
NORTHERN WASHINGTON/BRITISH COLUMBIA SOUTH TO OUR AREA DURING THE
PAST 36 HOURS. ADDITIONAL SHIFTING IS EXPECTED AS WELL AS TIMING
DIFFERENCES. STAY TUNED AS THIS SITUATION EVOLVES OVER TIME.
/JBONK

.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY...MODELS MAINTAIN A
FLATTENED RIDGE OVER THE EASTERN PACIFIC FOR THE WEEKEND THROUGH
EARLY NEXT WEEK. WITH A NEARLY ZONAL JET AND ABUNDANT
MOISTURE...EXPECT PLENTY OF RAINFALL TO CONTINUE THROUGH SUNDAY. ON
MONDAY AND TUESDAY...SOME WEAK RIDGING MOVES OVER THE REGION BUT
SHOWERS LIKELY CONTINUE IN THE MOIST ONSHORE FLOW. AN UPPER TROUGH
DROPS SOUTH OVER THE REGION BY MIDWEEK WITH SOME RATHER COLD AIR AND
ADDITIONAL PRECIPITATION IN STORE. WHILE STILL SOME SIGNIFICANT
UNCERTAINTY EXISTS WITH RESPECT TO THE TIMING OF THE PRECIP VS COLD
AIR AND JUST HOW COLD THE AIR IS...IT DOES APPEAR THAT A SIGNIFICANT
SURGE OF COLD AIR MAY MOVE INTO THE REGION AND THEREFORE...DECREASED
TEMPERATURES ACCORDINGLY FOR THE TUE/WED PERIODS ACROSS THE REGION.
IT DOES APPEAR THAT SNOW LEVELS WILL DROP BELOW PASS LEVELS AT
LEAST...AND PERHAPS DOWN INTO THE FOOTHILL ELEVATIONS LATER
WEDNESDAY INTO THURSDAY. GIVEN THE UNCERTAINTY...THOSE PLANNING
HOLIDAY TRAVEL DURING THIS PERIOD SHOULD MONITOR THE FORECAST.
CULLEN

&&

.AVIATION...VFR CONDITIONS LIKELY TO CONTINUE THROUGH THIS
AFTERNOON. ONSHORE WINDS THIS EVENING BEHIND THE WEAK LOW MOVING
ONSHORE WILL ALLOW FOR CIGS AND VIS TO LOWER TO IFR TONIGHT WITH
THE DEVELOPMENT OF FOG/LOW STRATUS. THIS SHOULD HOLD ON THROUGH
THURSDAY MORNING...STARTING TO LIFT BACK TOWARD VFR AROUND 15 TO 18Z
THURSDAY AS WINDS START TO INCREASE OUT OF THE SOUTH. VFR WILL
CONTINUE THROUGH THURSDAY AFTERNOON...THOUGH LOW-LEVEL WIND SHEAR
WILL BE A CONCERN AT KTTD AND POSSIBLY KPDX AS 20 KT EASTERLY
WINDS FROM THE GORGE UNDERCUT INCREASING SOUTHERLY WINDS ALOFT.

KPDX AND APPROACHES...VFR CONDITIONS TO PERSIST THIS
EVENING. WEAK WINDS WILL COULD PROMOTE THE DEVELOPMENT OF FOG/LOW
STRATUS AFTER 06Z THURSDAY...DROPPING CIGS AND VIS TO IFR. THIS
SHOULD LIFT BACK TO VFR BY 18Z THURSDAY. -MCCOY

&&

.MARINE...WEAK LOW PRESSURE SYSTEM MOVING NORTHWARD ALONG THE
COAST HAS BROUGHT WINDS UP TO SCA CRITERIA THIS AFTERNOON IN OUR
SOUTHERN WATERS. THIS IS WEAKENING AND MOVING ONSHORE...WHICH
SHOULD ALLOW WINDS TO SUBSIDE FOR A BRIEF PERIOD THIS EVENING.
WINDS WILL BEGIN TO INCREASE ACROSS OUR WATERS THURSDAY MORNING
AHEAD OF A COLD FRONT WHICH WILL MOVE THROUGH OUR WATERS DURING
THE DAY THURSDAY. AHEAD OF THIS FRONT...WINDS LIKELY TO RAMP UP TO
GALE FORCE WITH A COASTAL JET FULLY DEVELOPED BY THURSDAY
EVENING AND PERSIST UNTIL THE FRONT MOVES ONSHORE EARLY FRIDAY
MORNING.

SEAS CURRENTLY AROUND 10-12 FT WILL DROP TO 9 FT LATER THIS
EVENING. SEAS WILL BEGIN TO BUILD AGAIN THURSDAY MORNING AS WINDS
INCREASE AHEAD OF THE COLD FRONT ON THURSDAY. SEAS EXPECTED TO
BUILD TO THE LOW-TO-MIDDLE TEENS THURSDAY EVENING...SUBSIDING TO
10 TO 12 FT EARLY FRIDAY MORNING. A DYNAMIC FETCH APPROACHES EARLY
FRIDAY...BRINGING A LARGE SWELL INTO OUR WATERS. THIS WILL CAUSE
SEAS TO RAPIDLY BUILD FRIDAY MORNING...REACHING 20 FT FRIDAY
EVENING. THE NEXT STRONG FRONT APPROACHES ON SATURDAY...WITH
GALES POSSIBLE...COULD BUILD SEAS ALREADY 15 TO 20 FEET...TO 20
TO 25 FT SATURDAY. -MCCOY

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 4 AM TO 1 PM PST THURSDAY
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 60 NM.

     GALE WARNING FROM 1 PM THURSDAY TO MIDNIGHT PST THURSDAY NIGHT
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 9 PM PST THIS
     EVENING FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR WINDS UNTIL 1 PM PST THURSDAY FOR
     COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 4 AM PST THURSDAY.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.




000
FXUS66 KOTX 172252
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
252 PM PST WED DEC 17 2014

.SYNOPSIS...
A more active weather pattern will continue through the end of the
week with periods of light snow in the mountains...and rain or
snow in the valleys. Lower elevations from Interstate 90 south
will see mainly rain...while areas in the Cascades and near the
Canadian border will remain mainly snow. A much stronger weather
system over the weekend will usher in warmer temperatures with
sharply rising snow levels...as well as the potential for windy
conditions.

&&

.DISCUSSION...

Tonight and Tomorrow...A number of small weak disturbances running
across Eastern Washington and Northern Idaho through tonight and
tomorrow. They are very difficult to pick out in some of the
models as there is too much clutter in the flow associated with
the weakening baroclinic band upon where these disturbances are
located near that is currently passing through the area. They
haven`t been showing up too well in the radar either as they have
been far enough away for most of the day for the base elevation
beam to get a return on as well. Best bet to find these features
has been the IR satellite imagery on a fast rock and picking out
the small scale rotation and cloud top cooling. One such feature
is moving northeast this afternoon and is causing precipitation
just east of Moses Lake up to Omak and some points to the north
and east. A second feature, appearing to almost be a southern part
of the splitting/weakening baroclinic band has brought light rain
to Lewiston. All of these disturbances translate to the Northeast
and East at varying times tonight and tomorrow and as such the
pops and QPF show a general favoring of locations to the North and
East (including locations near Spokane down to Pullman) to receive
some precipitation but as expected the amounts are not too
significant...still it doesn`t take too much liquid to pool on
pavement that in turn cools overnight to allow for slick
conditions in spots similar to what occurred this morning.
/Pelatti

Thursday night through Sunday...An active weather pattern is
expected especially over the weekend with two systems to impacts
the Inland Northwest during this forecast period.

Thursday night/Friday: A large upper low seen on Infrared
Satellite Imagery in the Gulf of Alaska will drop southeast
sending a cold front across the area. The timing of the front
tracks into Central Washington Thursday night during the overnight
hours...reaching Eastern Washington and North Idaho Friday
morning. A north-south oriented jet parallel to the front and
southerly low/mid level flow will minimize downslope flow with all
areas likely to receive some precipitation. Inspection of model
soundings suggest this to be a mainly valley rain or rain/snow
mix...with snow in the mountains. 850mb winds backing to the south
will aid in bring up warmer air from the south. However a wedge of
cooler air trapped along the East Slopes of the Cascades will
result in lower snow levels over North Central Washington with the
potential for 2-3 inches of snow accumulation above 1000-1500
feet. This includes the Methow Valley, Plain, Waterville Plateau,
higher portions of Omak, and Republic. The Wenatchee area and
lower portions of the Okanogan and Columbia River valleys are
expected to see mainly a rain/snow mix or wet non-accumulating
snow. The mountains will generally see 2-5 inches of snow with the
Cascades seeing the highest amounts.

Saturday through Sunday...A much stronger system is expected this
weekend bringing a wide variety of expected weather. The models
continue to show an atmospheric river as a subtropical moisture
fetch becomes aimed at the area. The leading edge of this moisture
will enter on Saturday in the form of a warm front. Strong
isentropic lift will result in the development of widespread
rain and snow. 850mb winds backing to the south-southeast will
favor upslope flow into the northern mountains, with cooler air
remaining banked up into the Cascades, Okanogan Valley, and
Okanogan Highlands. Models suggest the potential for moderate to
locally heavy snow accumulations in these areas along and ahead of
the warm front before snow levels rise from south to north
Saturday night into Sunday morning. Snow levels will be fast to
rise from Interstate 90 south with precip expected to fall as
mainly valley rain and mountain snow. The valleys north of Spokane
such as Colville, Metaline Falls, Priest Lake, and Bonners Ferry
may start off as snow on Saturday with light accumulations...before
changing to rain Saturday night. As the warmer air aloft pokes
into the Cascades Saturday night...the valleys will likely have a
hard time mixing out with freezing rain possible especially south
of Lake Chelan in places like Plain and Leavenworth.

On Sunday the atmospheric river shifts south near the
Washington/Oregon border with strong westerly flow over the area.
This will lead to a strong rain shadow east of the Cascades with
precipitation likely confined mainly to the Cascade crest, Idaho
Panhandle, and southeast Washington. 850mb winds of 25-35 kts and
possible sun breaks across the Columbia Basin...and 850mb temps of
3-6C could lead to very mild temperatures along with breezy to
windy conditions. For now went a bit above MOS guidance which
usually does not go warm enough in these situations. JW

Sunday Nt through Christmas Eve: Following the passage of the windy
and wet short-wave trough that will move through broad upper
ridging Sunday Nt, what`s left of a stalled cold frontal boundary
will remain over Nrn Oregon and extreme Srn Wa Tues and keep the
threat of pcpn in the fcst for the Lewiston area as well as the Camas
Prairie. Where this front stalls will be critical as far as the
Christmas Eve fcst, because it is this boundary that will combine
with a significant short-wave trough and vort max moving into the
region as it translates SE down the BC coast. Deep cyclogenesis is
fcst by most model guidance over Ern Oregon Wednesday as the flow
backs and increases lift over the aforementioned boundary. As
pressure gradients increase, cold air will then begin to move into
Ern Wa from Srn Bc. Though it`s unusual even to see modest amnts
of agreement among models as to the placement of this deep low 7
days out, there still are enough differences how far south the
low will track that still make our level of confidence low as to where
potentially heavy snow bands may set up Christmas Eve. The trend,
however, has been slightly south which would keep the higher snow
threat out of Nrn Wa. Stay tuned... bz

&&

.AVIATION...
18Z TAFS: Weak disturbances drifting northeast and over the
aviation over the next 24 hours keep the forecast somewhat
cluttered with mentions of both rain and snow at times which
produce IFR/LIFR ceilings and visibilities. Some fog will
occasionally impact locations as well. Precipitation still on the
light side with the higher amounts primarily near the East Slopes
of the North Cascades out to the Waterville Plateau and points to
the north/northeast. The KGEG area will be more MVFR most of the
time as the precipitation will be light and likely to be rain.
/Pelatti

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        32  37  33  39  31  40 /  50  30  40  90  10  70
Coeur d`Alene  33  38  32  39  32  39 /  60  60  20 100  20  70
Pullman        33  43  34  42  32  43 /  50  40  40  90  10  70
Lewiston       35  45  36  46  33  47 /  40  30  20  70  10  40
Colville       32  37  34  38  32  38 /  60  30  60 100  10  80
Sandpoint      32  37  32  36  31  38 /  60  60  30 100  40  60
Kellogg        32  38  32  36  31  36 /  70  70  20 100  40  60
Moses Lake     29  39  36  42  30  39 /  20  10  70  70  10  70
Wenatchee      31  37  33  40  30  34 /  30  10  70  60  10  70
Omak           27  34  32  37  30  33 /  40  10  80  80  10  80

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 172252
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
252 PM PST WED DEC 17 2014

.SYNOPSIS...
A more active weather pattern will continue through the end of the
week with periods of light snow in the mountains...and rain or
snow in the valleys. Lower elevations from Interstate 90 south
will see mainly rain...while areas in the Cascades and near the
Canadian border will remain mainly snow. A much stronger weather
system over the weekend will usher in warmer temperatures with
sharply rising snow levels...as well as the potential for windy
conditions.

&&

.DISCUSSION...

Tonight and Tomorrow...A number of small weak disturbances running
across Eastern Washington and Northern Idaho through tonight and
tomorrow. They are very difficult to pick out in some of the
models as there is too much clutter in the flow associated with
the weakening baroclinic band upon where these disturbances are
located near that is currently passing through the area. They
haven`t been showing up too well in the radar either as they have
been far enough away for most of the day for the base elevation
beam to get a return on as well. Best bet to find these features
has been the IR satellite imagery on a fast rock and picking out
the small scale rotation and cloud top cooling. One such feature
is moving northeast this afternoon and is causing precipitation
just east of Moses Lake up to Omak and some points to the north
and east. A second feature, appearing to almost be a southern part
of the splitting/weakening baroclinic band has brought light rain
to Lewiston. All of these disturbances translate to the Northeast
and East at varying times tonight and tomorrow and as such the
pops and QPF show a general favoring of locations to the North and
East (including locations near Spokane down to Pullman) to receive
some precipitation but as expected the amounts are not too
significant...still it doesn`t take too much liquid to pool on
pavement that in turn cools overnight to allow for slick
conditions in spots similar to what occurred this morning.
/Pelatti

Thursday night through Sunday...An active weather pattern is
expected especially over the weekend with two systems to impacts
the Inland Northwest during this forecast period.

Thursday night/Friday: A large upper low seen on Infrared
Satellite Imagery in the Gulf of Alaska will drop southeast
sending a cold front across the area. The timing of the front
tracks into Central Washington Thursday night during the overnight
hours...reaching Eastern Washington and North Idaho Friday
morning. A north-south oriented jet parallel to the front and
southerly low/mid level flow will minimize downslope flow with all
areas likely to receive some precipitation. Inspection of model
soundings suggest this to be a mainly valley rain or rain/snow
mix...with snow in the mountains. 850mb winds backing to the south
will aid in bring up warmer air from the south. However a wedge of
cooler air trapped along the East Slopes of the Cascades will
result in lower snow levels over North Central Washington with the
potential for 2-3 inches of snow accumulation above 1000-1500
feet. This includes the Methow Valley, Plain, Waterville Plateau,
higher portions of Omak, and Republic. The Wenatchee area and
lower portions of the Okanogan and Columbia River valleys are
expected to see mainly a rain/snow mix or wet non-accumulating
snow. The mountains will generally see 2-5 inches of snow with the
Cascades seeing the highest amounts.

Saturday through Sunday...A much stronger system is expected this
weekend bringing a wide variety of expected weather. The models
continue to show an atmospheric river as a subtropical moisture
fetch becomes aimed at the area. The leading edge of this moisture
will enter on Saturday in the form of a warm front. Strong
isentropic lift will result in the development of widespread
rain and snow. 850mb winds backing to the south-southeast will
favor upslope flow into the northern mountains, with cooler air
remaining banked up into the Cascades, Okanogan Valley, and
Okanogan Highlands. Models suggest the potential for moderate to
locally heavy snow accumulations in these areas along and ahead of
the warm front before snow levels rise from south to north
Saturday night into Sunday morning. Snow levels will be fast to
rise from Interstate 90 south with precip expected to fall as
mainly valley rain and mountain snow. The valleys north of Spokane
such as Colville, Metaline Falls, Priest Lake, and Bonners Ferry
may start off as snow on Saturday with light accumulations...before
changing to rain Saturday night. As the warmer air aloft pokes
into the Cascades Saturday night...the valleys will likely have a
hard time mixing out with freezing rain possible especially south
of Lake Chelan in places like Plain and Leavenworth.

On Sunday the atmospheric river shifts south near the
Washington/Oregon border with strong westerly flow over the area.
This will lead to a strong rain shadow east of the Cascades with
precipitation likely confined mainly to the Cascade crest, Idaho
Panhandle, and southeast Washington. 850mb winds of 25-35 kts and
possible sun breaks across the Columbia Basin...and 850mb temps of
3-6C could lead to very mild temperatures along with breezy to
windy conditions. For now went a bit above MOS guidance which
usually does not go warm enough in these situations. JW

Sunday Nt through Christmas Eve: Following the passage of the windy
and wet short-wave trough that will move through broad upper
ridging Sunday Nt, what`s left of a stalled cold frontal boundary
will remain over Nrn Oregon and extreme Srn Wa Tues and keep the
threat of pcpn in the fcst for the Lewiston area as well as the Camas
Prairie. Where this front stalls will be critical as far as the
Christmas Eve fcst, because it is this boundary that will combine
with a significant short-wave trough and vort max moving into the
region as it translates SE down the BC coast. Deep cyclogenesis is
fcst by most model guidance over Ern Oregon Wednesday as the flow
backs and increases lift over the aforementioned boundary. As
pressure gradients increase, cold air will then begin to move into
Ern Wa from Srn Bc. Though it`s unusual even to see modest amnts
of agreement among models as to the placement of this deep low 7
days out, there still are enough differences how far south the
low will track that still make our level of confidence low as to where
potentially heavy snow bands may set up Christmas Eve. The trend,
however, has been slightly south which would keep the higher snow
threat out of Nrn Wa. Stay tuned... bz

&&

.AVIATION...
18Z TAFS: Weak disturbances drifting northeast and over the
aviation over the next 24 hours keep the forecast somewhat
cluttered with mentions of both rain and snow at times which
produce IFR/LIFR ceilings and visibilities. Some fog will
occasionally impact locations as well. Precipitation still on the
light side with the higher amounts primarily near the East Slopes
of the North Cascades out to the Waterville Plateau and points to
the north/northeast. The KGEG area will be more MVFR most of the
time as the precipitation will be light and likely to be rain.
/Pelatti

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        32  37  33  39  31  40 /  50  30  40  90  10  70
Coeur d`Alene  33  38  32  39  32  39 /  60  60  20 100  20  70
Pullman        33  43  34  42  32  43 /  50  40  40  90  10  70
Lewiston       35  45  36  46  33  47 /  40  30  20  70  10  40
Colville       32  37  34  38  32  38 /  60  30  60 100  10  80
Sandpoint      32  37  32  36  31  38 /  60  60  30 100  40  60
Kellogg        32  38  32  36  31  36 /  70  70  20 100  40  60
Moses Lake     29  39  36  42  30  39 /  20  10  70  70  10  70
Wenatchee      31  37  33  40  30  34 /  30  10  70  60  10  70
Omak           27  34  32  37  30  33 /  40  10  80  80  10  80

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KPQR 172252
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
252 PM PST WED DEC 17 2014

.SYNOPSIS...WEAK LOW PRESSURE WILL CROSS THE AREA THIS EVENING WITH
SHOWERS LINGERING OVERNIGHT. EXPECT FAIRLY QUIET WEATHER TO START
THE DAY THURSDAY. A MORE ORGANIZED FRONT WILL BRING GUSTY WINDS TO
THE COAST WITH RAIN SPREADING INLAND THURSDAY NIGHT AND FRIDAY.
RISING SNOW LEVELS WILL LIMIT SNOW TO THE HIGHEST PEAKS. COLDER AIR
BEHIND THE FRONT WILL BRING ACCUMULATING SNOW SHOWERS FOR THE
CASCADES PASSES FRIDAY EVENING AND SATURDAY. MILD AND VERY WET
WEATHER ARRIVED THIS WEEKEND. THERE IS POTENTIAL FOR AN ATMOSPHERIC
RIVER AND ASSOCIATED HEAVY RAIN TO DEVELOP OVER THE AREA AFFECTING
RIVERS INTO NEXT WEEK.

&&

.SHORT TERM...TONIGHT THROUGH SATURDAY...A WEAK AND SPLITTING TROUGH
WILL SEND MOST OF ITS ENERGY SOUTH OF OUR AREA TONIGHT. WILL SEE
SHOWERS TAPER OFF OVERNIGHT AS HIGH PRESSURE BEGINS A TRANSIT ACROSS
THE AREA. WILL ALSO SEE CORRESPONDING SNOW LEVELS RISE ABOVE THE
PASSES AND GENERALLY LIMIT THE AMOUNT OF ACCUMULATIONS. THE RIDGE
AXIS QUICKLY PASSES EAST BY TOMORROW AFTERNOON LEADING TO A LARGELY
DRY DAY FOR THE INTERIOR.

ANOTHER MORE COHESIVE TROUGH AND FRONTAL SYSTEM WILL DIG OFFSHORE
WITH WARM FRONTAL RAIN TOUCHING THE COAST LATE FRIDAY AFTERNOON WITH
HEAVIER AMOUNTS BY EARLY FRIDAY EVENING. TIMING COULD BE EARLIER
DEPENDING ON MODEL OF CHOICE WITH THE GFS PERHAPS A COUPLE HOURS
FASTER THAN THE ECMWF AND THE NAM SLOWER YET. NAM TYPICALLY DOES NOT
HANDLE WARM PROCESS RAIN VERY WELL SO AM PUTTING LESS WEIGHT ON IT
TO START WITH. AS THE RAIN COMES IN...A COASTAL JET DEVELOPS
BRINGING FAIRLY GUSTY WINDS TO THE COAST AND COAST RANGE BUT NOTHING
TOO OUT OF THE ORDINARY. NOT ANTICIPATING ANY HIGHLIGHTS BUT
PROBABLY A RUN OF THE MILL WINDY COASTAL STORM. THE ASSOCIATED COLD
FRONT COME ASHORE AROUND 12Z FRIDAY MORNING AND CROSSES THE CASCADES
AROUND 17Z WITH COLDER AIR AND LOWERING SNOW LEVELS WITH AND MORE SO
BEHIND IT. PRECIPITATION TAPERS OFF AND BECOMES MORE SHOWERY IN
NATURE BEHIND THE FRONT. EXPECT LIGHT ACCUMULATING SNOW BEGINS AT
WILLAMETTE PASS AROUND DAY BREAK AND LOWERS TO NEAR GOVERNMENT PASS
LATER THAT MORNING. THE SNOW COMES TO BE TOO LITTLE...TOO LATE FOR
MUCH APPRECIABLE INCREASE IN THE SNOW PACK WITH PERHAPS A FEW INCHES
AT THE HIGHER PASSES AND LESS THAN AN INCH FOR GOVERNMENT CAMP.
HIGHER PEAKS COULD SEE UP TO A FOOT...HOWEVER. ANY OF THE MID
ELEVATION SNOW WILL BE RATHER SHORT-LIVED AS SNOW LEVELS IMMEDIATELY
BEGIN RISING IN ANTICIPATION OF THE PACIFIC STORM TRACK BECOMING
CENTERED OVER THE AREA.

MAIN ATTENTION THIS SHIFT HAS BEEN BE PLACED ON THE ATMOSPHERIC
RIVER EVENT SETTING UP TO AFFECT THE REGION THIS WEEKEND WITH
IMPACTS LASTING INTO NEXT WEEK. RAW GFS MODEL RUN ACCUMULATED QPF
AMOUNTS EXCEED 12 INCHES FOR PORTIONS OF THE CASCADES AND 10 INCHES
FOR THE COAST RANGE ENDING MONDAY MORNING. WILL SEE THE WARM RAINS
BEGIN AFFECTING THE COAST RANGE SATURDAY MORNING AND PUSH QUICKLY
INLAND TO THE CASCADES BY SATURDAY AFTERNOON. MOST OF THE HEAVY RAIN
OCCURS BEGINNING SATURDAY NIGHT. THERE WOULD BE DEEP WESTERLY FLOW
FROM THE SURFACE UP TO THE JET LEVEL THUS EXPECT THIS COULD BE AN
IDEAL OROGRAPHIC SITUATION TO EXTRACT A MAXIMUM AMOUNT OF RAIN FROM
WHATEVER COMES ASHORE. THERE IS GENERAL LARGE SCALE SUPPORT FROM THE
ECMWF ALBEIT WITH LESS QPF. PAST EXPERIENCE SHOWS FOLLOWING THE
HIGHER GFS QPF AMOUNTS IS STILL NOT ENOUGH AND THAT REALITY BRINGS
SIGNIFICANTLY MORE RAIN. ASSUMING THE CURRENT MODEL RUNS STAY
UNCHANGED IN THE FUTURE...WOULD EXPECT MULTIPLE MAINSTEM RIVERS
EXCEEDING FLOOD STAGE AS SOON AS SUNDAY EVENING.

HAVE ISSUED SOME OUTLOOK PRODUCTS TODAY LOOKING AHEAD TO FLOODING
POTENTIAL WITH THE CAVEAT THAT MODELS HAVE SHIFTED THE FOCUS FROM
NORTHERN WASHINGTON/BRITISH COLUMBIA SOUTH TO OUR AREA DURING THE
PAST 36 HOURS. ADDITIONAL SHIFTING IS EXPECTED AS WELL AS TIMING
DIFFERENCES. STAY TUNED AS THIS SITUATION EVOLVES OVER TIME.
/JBONK

.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY...MODELS MAINTAIN A
FLATTENED RIDGE OVER THE EASTERN PACIFIC FOR THE WEEKEND THROUGH
EARLY NEXT WEEK. WITH A NEARLY ZONAL JET AND ABUNDANT
MOISTURE...EXPECT PLENTY OF RAINFALL TO CONTINUE THROUGH SUNDAY. ON
MONDAY AND TUESDAY...SOME WEAK RIDGING MOVES OVER THE REGION BUT
SHOWERS LIKELY CONTINUE IN THE MOIST ONSHORE FLOW. AN UPPER TROUGH
DROPS SOUTH OVER THE REGION BY MIDWEEK WITH SOME RATHER COLD AIR AND
ADDITIONAL PRECIPITATION IN STORE. WHILE STILL SOME SIGNIFICANT
UNCERTAINTY EXISTS WITH RESPECT TO THE TIMING OF THE PRECIP VS COLD
AIR AND JUST HOW COLD THE AIR IS...IT DOES APPEAR THAT A SIGNIFICANT
SURGE OF COLD AIR MAY MOVE INTO THE REGION AND THEREFORE...DECREASED
TEMPERATURES ACCORDINGLY FOR THE TUE/WED PERIODS ACROSS THE REGION.
IT DOES APPEAR THAT SNOW LEVELS WILL DROP BELOW PASS LEVELS AT
LEAST...AND PERHAPS DOWN INTO THE FOOTHILL ELEVATIONS LATER
WEDNESDAY INTO THURSDAY. GIVEN THE UNCERTAINTY...THOSE PLANNING
HOLIDAY TRAVEL DURING THIS PERIOD SHOULD MONITOR THE FORECAST.
CULLEN

&&

.AVIATION...VFR CONDITIONS LIKELY TO CONTINUE THROUGH THIS
AFTERNOON. ONSHORE WINDS THIS EVENING BEHIND THE WEAK LOW MOVING
ONSHORE WILL ALLOW FOR CIGS AND VIS TO LOWER TO IFR TONIGHT WITH
THE DEVELOPMENT OF FOG/LOW STRATUS. THIS SHOULD HOLD ON THROUGH
THURSDAY MORNING...STARTING TO LIFT BACK TOWARD VFR AROUND 15 TO 18Z
THURSDAY AS WINDS START TO INCREASE OUT OF THE SOUTH. VFR WILL
CONTINUE THROUGH THURSDAY AFTERNOON...THOUGH LOW-LEVEL WIND SHEAR
WILL BE A CONCERN AT KTTD AND POSSIBLY KPDX AS 20 KT EASTERLY
WINDS FROM THE GORGE UNDERCUT INCREASING SOUTHERLY WINDS ALOFT.

KPDX AND APPROACHES...VFR CONDITIONS TO PERSIST THIS
EVENING. WEAK WINDS WILL COULD PROMOTE THE DEVELOPMENT OF FOG/LOW
STRATUS AFTER 06Z THURSDAY...DROPPING CIGS AND VIS TO IFR. THIS
SHOULD LIFT BACK TO VFR BY 18Z THURSDAY. -MCCOY

&&

.MARINE...WEAK LOW PRESSURE SYSTEM MOVING NORTHWARD ALONG THE
COAST HAS BROUGHT WINDS UP TO SCA CRITERIA THIS AFTERNOON IN OUR
SOUTHERN WATERS. THIS IS WEAKENING AND MOVING ONSHORE...WHICH
SHOULD ALLOW WINDS TO SUBSIDE FOR A BRIEF PERIOD THIS EVENING.
WINDS WILL BEGIN TO INCREASE ACROSS OUR WATERS THURSDAY MORNING
AHEAD OF A COLD FRONT WHICH WILL MOVE THROUGH OUR WATERS DURING
THE DAY THURSDAY. AHEAD OF THIS FRONT...WINDS LIKELY TO RAMP UP TO
GALE FORCE WITH A COASTAL JET FULLY DEVELOPED BY THURSDAY
EVENING AND PERSIST UNTIL THE FRONT MOVES ONSHORE EARLY FRIDAY
MORNING.

SEAS CURRENTLY AROUND 10-12 FT WILL DROP TO 9 FT LATER THIS
EVENING. SEAS WILL BEGIN TO BUILD AGAIN THURSDAY MORNING AS WINDS
INCREASE AHEAD OF THE COLD FRONT ON THURSDAY. SEAS EXPECTED TO
BUILD TO THE LOW-TO-MIDDLE TEENS THURSDAY EVENING...SUBSIDING TO
10 TO 12 FT EARLY FRIDAY MORNING. A DYNAMIC FETCH APPROACHES EARLY
FRIDAY...BRINGING A LARGE SWELL INTO OUR WATERS. THIS WILL CAUSE
SEAS TO RAPIDLY BUILD FRIDAY MORNING...REACHING 20 FT FRIDAY
EVENING. THE NEXT STRONG FRONT APPROACHES ON SATURDAY...WITH
GALES POSSIBLE...COULD BUILD SEAS ALREADY 15 TO 20 FEET...TO 20
TO 25 FT SATURDAY. -MCCOY

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 4 AM TO 1 PM PST THURSDAY
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 60 NM.

     GALE WARNING FROM 1 PM THURSDAY TO MIDNIGHT PST THURSDAY NIGHT
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 9 PM PST THIS
     EVENING FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR WINDS UNTIL 1 PM PST THURSDAY FOR
     COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 4 AM PST THURSDAY.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.




000
FXUS66 KPQR 172252
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
252 PM PST WED DEC 17 2014

.SYNOPSIS...WEAK LOW PRESSURE WILL CROSS THE AREA THIS EVENING WITH
SHOWERS LINGERING OVERNIGHT. EXPECT FAIRLY QUIET WEATHER TO START
THE DAY THURSDAY. A MORE ORGANIZED FRONT WILL BRING GUSTY WINDS TO
THE COAST WITH RAIN SPREADING INLAND THURSDAY NIGHT AND FRIDAY.
RISING SNOW LEVELS WILL LIMIT SNOW TO THE HIGHEST PEAKS. COLDER AIR
BEHIND THE FRONT WILL BRING ACCUMULATING SNOW SHOWERS FOR THE
CASCADES PASSES FRIDAY EVENING AND SATURDAY. MILD AND VERY WET
WEATHER ARRIVED THIS WEEKEND. THERE IS POTENTIAL FOR AN ATMOSPHERIC
RIVER AND ASSOCIATED HEAVY RAIN TO DEVELOP OVER THE AREA AFFECTING
RIVERS INTO NEXT WEEK.

&&

.SHORT TERM...TONIGHT THROUGH SATURDAY...A WEAK AND SPLITTING TROUGH
WILL SEND MOST OF ITS ENERGY SOUTH OF OUR AREA TONIGHT. WILL SEE
SHOWERS TAPER OFF OVERNIGHT AS HIGH PRESSURE BEGINS A TRANSIT ACROSS
THE AREA. WILL ALSO SEE CORRESPONDING SNOW LEVELS RISE ABOVE THE
PASSES AND GENERALLY LIMIT THE AMOUNT OF ACCUMULATIONS. THE RIDGE
AXIS QUICKLY PASSES EAST BY TOMORROW AFTERNOON LEADING TO A LARGELY
DRY DAY FOR THE INTERIOR.

ANOTHER MORE COHESIVE TROUGH AND FRONTAL SYSTEM WILL DIG OFFSHORE
WITH WARM FRONTAL RAIN TOUCHING THE COAST LATE FRIDAY AFTERNOON WITH
HEAVIER AMOUNTS BY EARLY FRIDAY EVENING. TIMING COULD BE EARLIER
DEPENDING ON MODEL OF CHOICE WITH THE GFS PERHAPS A COUPLE HOURS
FASTER THAN THE ECMWF AND THE NAM SLOWER YET. NAM TYPICALLY DOES NOT
HANDLE WARM PROCESS RAIN VERY WELL SO AM PUTTING LESS WEIGHT ON IT
TO START WITH. AS THE RAIN COMES IN...A COASTAL JET DEVELOPS
BRINGING FAIRLY GUSTY WINDS TO THE COAST AND COAST RANGE BUT NOTHING
TOO OUT OF THE ORDINARY. NOT ANTICIPATING ANY HIGHLIGHTS BUT
PROBABLY A RUN OF THE MILL WINDY COASTAL STORM. THE ASSOCIATED COLD
FRONT COME ASHORE AROUND 12Z FRIDAY MORNING AND CROSSES THE CASCADES
AROUND 17Z WITH COLDER AIR AND LOWERING SNOW LEVELS WITH AND MORE SO
BEHIND IT. PRECIPITATION TAPERS OFF AND BECOMES MORE SHOWERY IN
NATURE BEHIND THE FRONT. EXPECT LIGHT ACCUMULATING SNOW BEGINS AT
WILLAMETTE PASS AROUND DAY BREAK AND LOWERS TO NEAR GOVERNMENT PASS
LATER THAT MORNING. THE SNOW COMES TO BE TOO LITTLE...TOO LATE FOR
MUCH APPRECIABLE INCREASE IN THE SNOW PACK WITH PERHAPS A FEW INCHES
AT THE HIGHER PASSES AND LESS THAN AN INCH FOR GOVERNMENT CAMP.
HIGHER PEAKS COULD SEE UP TO A FOOT...HOWEVER. ANY OF THE MID
ELEVATION SNOW WILL BE RATHER SHORT-LIVED AS SNOW LEVELS IMMEDIATELY
BEGIN RISING IN ANTICIPATION OF THE PACIFIC STORM TRACK BECOMING
CENTERED OVER THE AREA.

MAIN ATTENTION THIS SHIFT HAS BEEN BE PLACED ON THE ATMOSPHERIC
RIVER EVENT SETTING UP TO AFFECT THE REGION THIS WEEKEND WITH
IMPACTS LASTING INTO NEXT WEEK. RAW GFS MODEL RUN ACCUMULATED QPF
AMOUNTS EXCEED 12 INCHES FOR PORTIONS OF THE CASCADES AND 10 INCHES
FOR THE COAST RANGE ENDING MONDAY MORNING. WILL SEE THE WARM RAINS
BEGIN AFFECTING THE COAST RANGE SATURDAY MORNING AND PUSH QUICKLY
INLAND TO THE CASCADES BY SATURDAY AFTERNOON. MOST OF THE HEAVY RAIN
OCCURS BEGINNING SATURDAY NIGHT. THERE WOULD BE DEEP WESTERLY FLOW
FROM THE SURFACE UP TO THE JET LEVEL THUS EXPECT THIS COULD BE AN
IDEAL OROGRAPHIC SITUATION TO EXTRACT A MAXIMUM AMOUNT OF RAIN FROM
WHATEVER COMES ASHORE. THERE IS GENERAL LARGE SCALE SUPPORT FROM THE
ECMWF ALBEIT WITH LESS QPF. PAST EXPERIENCE SHOWS FOLLOWING THE
HIGHER GFS QPF AMOUNTS IS STILL NOT ENOUGH AND THAT REALITY BRINGS
SIGNIFICANTLY MORE RAIN. ASSUMING THE CURRENT MODEL RUNS STAY
UNCHANGED IN THE FUTURE...WOULD EXPECT MULTIPLE MAINSTEM RIVERS
EXCEEDING FLOOD STAGE AS SOON AS SUNDAY EVENING.

HAVE ISSUED SOME OUTLOOK PRODUCTS TODAY LOOKING AHEAD TO FLOODING
POTENTIAL WITH THE CAVEAT THAT MODELS HAVE SHIFTED THE FOCUS FROM
NORTHERN WASHINGTON/BRITISH COLUMBIA SOUTH TO OUR AREA DURING THE
PAST 36 HOURS. ADDITIONAL SHIFTING IS EXPECTED AS WELL AS TIMING
DIFFERENCES. STAY TUNED AS THIS SITUATION EVOLVES OVER TIME.
/JBONK

.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY...MODELS MAINTAIN A
FLATTENED RIDGE OVER THE EASTERN PACIFIC FOR THE WEEKEND THROUGH
EARLY NEXT WEEK. WITH A NEARLY ZONAL JET AND ABUNDANT
MOISTURE...EXPECT PLENTY OF RAINFALL TO CONTINUE THROUGH SUNDAY. ON
MONDAY AND TUESDAY...SOME WEAK RIDGING MOVES OVER THE REGION BUT
SHOWERS LIKELY CONTINUE IN THE MOIST ONSHORE FLOW. AN UPPER TROUGH
DROPS SOUTH OVER THE REGION BY MIDWEEK WITH SOME RATHER COLD AIR AND
ADDITIONAL PRECIPITATION IN STORE. WHILE STILL SOME SIGNIFICANT
UNCERTAINTY EXISTS WITH RESPECT TO THE TIMING OF THE PRECIP VS COLD
AIR AND JUST HOW COLD THE AIR IS...IT DOES APPEAR THAT A SIGNIFICANT
SURGE OF COLD AIR MAY MOVE INTO THE REGION AND THEREFORE...DECREASED
TEMPERATURES ACCORDINGLY FOR THE TUE/WED PERIODS ACROSS THE REGION.
IT DOES APPEAR THAT SNOW LEVELS WILL DROP BELOW PASS LEVELS AT
LEAST...AND PERHAPS DOWN INTO THE FOOTHILL ELEVATIONS LATER
WEDNESDAY INTO THURSDAY. GIVEN THE UNCERTAINTY...THOSE PLANNING
HOLIDAY TRAVEL DURING THIS PERIOD SHOULD MONITOR THE FORECAST.
CULLEN

&&

.AVIATION...VFR CONDITIONS LIKELY TO CONTINUE THROUGH THIS
AFTERNOON. ONSHORE WINDS THIS EVENING BEHIND THE WEAK LOW MOVING
ONSHORE WILL ALLOW FOR CIGS AND VIS TO LOWER TO IFR TONIGHT WITH
THE DEVELOPMENT OF FOG/LOW STRATUS. THIS SHOULD HOLD ON THROUGH
THURSDAY MORNING...STARTING TO LIFT BACK TOWARD VFR AROUND 15 TO 18Z
THURSDAY AS WINDS START TO INCREASE OUT OF THE SOUTH. VFR WILL
CONTINUE THROUGH THURSDAY AFTERNOON...THOUGH LOW-LEVEL WIND SHEAR
WILL BE A CONCERN AT KTTD AND POSSIBLY KPDX AS 20 KT EASTERLY
WINDS FROM THE GORGE UNDERCUT INCREASING SOUTHERLY WINDS ALOFT.

KPDX AND APPROACHES...VFR CONDITIONS TO PERSIST THIS
EVENING. WEAK WINDS WILL COULD PROMOTE THE DEVELOPMENT OF FOG/LOW
STRATUS AFTER 06Z THURSDAY...DROPPING CIGS AND VIS TO IFR. THIS
SHOULD LIFT BACK TO VFR BY 18Z THURSDAY. -MCCOY

&&

.MARINE...WEAK LOW PRESSURE SYSTEM MOVING NORTHWARD ALONG THE
COAST HAS BROUGHT WINDS UP TO SCA CRITERIA THIS AFTERNOON IN OUR
SOUTHERN WATERS. THIS IS WEAKENING AND MOVING ONSHORE...WHICH
SHOULD ALLOW WINDS TO SUBSIDE FOR A BRIEF PERIOD THIS EVENING.
WINDS WILL BEGIN TO INCREASE ACROSS OUR WATERS THURSDAY MORNING
AHEAD OF A COLD FRONT WHICH WILL MOVE THROUGH OUR WATERS DURING
THE DAY THURSDAY. AHEAD OF THIS FRONT...WINDS LIKELY TO RAMP UP TO
GALE FORCE WITH A COASTAL JET FULLY DEVELOPED BY THURSDAY
EVENING AND PERSIST UNTIL THE FRONT MOVES ONSHORE EARLY FRIDAY
MORNING.

SEAS CURRENTLY AROUND 10-12 FT WILL DROP TO 9 FT LATER THIS
EVENING. SEAS WILL BEGIN TO BUILD AGAIN THURSDAY MORNING AS WINDS
INCREASE AHEAD OF THE COLD FRONT ON THURSDAY. SEAS EXPECTED TO
BUILD TO THE LOW-TO-MIDDLE TEENS THURSDAY EVENING...SUBSIDING TO
10 TO 12 FT EARLY FRIDAY MORNING. A DYNAMIC FETCH APPROACHES EARLY
FRIDAY...BRINGING A LARGE SWELL INTO OUR WATERS. THIS WILL CAUSE
SEAS TO RAPIDLY BUILD FRIDAY MORNING...REACHING 20 FT FRIDAY
EVENING. THE NEXT STRONG FRONT APPROACHES ON SATURDAY...WITH
GALES POSSIBLE...COULD BUILD SEAS ALREADY 15 TO 20 FEET...TO 20
TO 25 FT SATURDAY. -MCCOY

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 4 AM TO 1 PM PST THURSDAY
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 60 NM.

     GALE WARNING FROM 1 PM THURSDAY TO MIDNIGHT PST THURSDAY NIGHT
     FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 9 PM PST THIS
     EVENING FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR WINDS UNTIL 1 PM PST THURSDAY FOR
     COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 4 AM PST THURSDAY.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.



  [top]

000
FXUS66 KSEW 172249
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 PM PST WED DEC 17 2014

.SYNOPSIS...A WEAK FRONT WILL DISSIPATE OVER THE REGION TONIGHT AND
EARLY THURSDAY. THE NEXT STRONGER PACIFIC FRONTAL SYSTEM WILL MOVE
ASHORE THURSDAY NIGHT WITH MORE SIGNIFICANT RAIN AND SOME MOUNTAIN
SNOW. ANOTHER WET WEATHER SYSTEM IS FORECAST FOR THIS WEEKEND WITH
HEAVIER RAIN AMOUNTS ALONG THE COAST AND IN THE MOUNTAINS. COOLER
AND MORE SHOWERY WEATHER MAY DEVELOP BY THE MIDDLE OF NEXT WEEK.

&&

.SHORT TERM...MOIST SW FLOW ALOFT CONTINUES OVER THE PAC NW AHEAD OF
AN APPROACHING SPLIT NRN STREAM TROUGH. PRECIPITATION WAS LIGHT
TODAY WITH MOST SPOTS RECEIVING LESS THAN ONE TENTH OF AN INCH. THE
NEXT BATCH OF RAIN WILL ALSO BE LIGHT THIS EVENING WITH JUST MINOR
MEASURABLE AMOUNTS FOR MOST PLACES. SATELLITE IMAGERY SHOWS MORE
PRONOUNCED SPLITTING OF THE FRONTAL BAND STARTING TO MOVE INLAND.
HRRR AND NAM12 MODELS STILL KEEP LIGHT RAIN AROUND THE AREA...AT
LEAST THROUGH THE EVENING HOURS BEFORE DECREASING. WILL MAINTAIN THE
CHANCE POPS WITH MORE UNCERTAINTY THAN USUAL FOR THE FIRST PERIOD
FORECAST.

LIGHT SHOWERS MAY LINGER INTO THURSDAY MORNING BUT AN UPPER LEVEL
RIDGE WILL BE MOVING ACROSS WRN WA DURING THE DAY. THE NAM12 SHOWS
SOME LIGHT SPOTTY QPF OVER THE AREA UNTIL THE NEXT STRONGER FRONTAL
SYSTEM ARRIVES LATER IN THE DAY. CONSIDERATION WAS GIVEN TO DRYING
OUT THE MORNING PERIOD FOR INLAND AREAS BUT GIVEN THE NAM12...SOME
LIGHT PRECIPITATION CANNOT BE RULED OUT AND CHANCE POPS WILL BE
MAINTAINED.

MODELS AGREE THAT RAIN WILL DEVELOP ON THE COAST LATE IN THE DAY
WITH A WEAK WARM FRONTAL FEATURE. THE TRAILING COLD FRONT WILL
QUICKLY FOLLOW...PUSHING THROUGH WRN WA THURSDAY NIGHT. THIS SYSTEM
WILL BRING MORE RAIN THAN PREVIOUS SYSTEMS AND ALSO SOME COOLER AIR
WITH LOWERING SNOW LEVELS. A FEW INCHES OF SNOW ARE STILL EXPECTED
IN THE MOUNTAINS ABOVE ABOVE 4000 FEET ONCE THE SNOW LEVELS DROPS
OFF THURSDAY NIGHT. ABOVE 5500 FEET...UP TO 6 INCHES COULD
FALL...MAINLY ALONG S/SW FACING SLOPES OF MOUNT BAKER AND MOUNT
RAINIER.

RAIN WILL CHANGE OVER TO SHOWERS IN THE LOWLANDS FRIDAY AND SNOW
WILL TAPER OFF IN THE MOUNTAINS. A LULL IN PRECIPITATION IS EXPECTED
BETWEEN STORM SYSTEMS POSSIBLY THROUGH MUCH OF FRIDAY NIGHT BUT
MODELS DIFFER SLIGHTLY ON THE TIMING OF THE NEXT FRONT.

MODELS HOW A STRONG WARM FRONT TO SPREAD RAIN INTO WRN WA BY
SATURDAY MORNING. A MOIST WESTERLY FLOW PATTERN WILL BE DIRECTED
INTO WRN WA/WRN OREGON BY SATURDAY NIGHT AND SUNDAY. THE 12Z ECMWF
HAS TRENDED TOWARD THE PAST 2-3 GFS40 RUNS SAGGING THE MOISTURE PLUM
SWD ON SUNDAY AFTERNOON. THIS WOULD SHIFT HEAVIER MOUNTAIN RAIN INTO
THE CASCADES OF SRN WA/AND OREGON WITH LIGHTER FURTHER N OVER THE
CENTRAL/N WA CASCADES. WHILE MODELS HAVE TRENDED TOWARD LESS
PRECIPITATION OVER THE WA CASCADES THE MODELS HAVE YET TO LATCH ON
TO ONE PARTICULAR SOLUTION SO UNCERTAINTY REMAINS HIGH ON WHERE THE
HEAVIEST RAIN WILL FALL. SEE THE HYDRO DISCUSSION BELOW FOR FURTHER
DETAILS.

.LONG TERM...MODELS NOW SHOW A BREAK OR AT LEAST DECREASE IN
RAINFALL RATES SUNDAY NIGHT AS WEAK HIGH PRESSURE TEMPORARILY BUILDS
OFFSHORE. THE RIDGE WILL LIFT THE FLOW NWD SO MOISTURE DIRECTED INTO
SRN WA/OREGON WILL LIFT BACK OVER WRN WA ON MONDAY. THE RIDGING IS
QUITE A BIT STRONGER ON MOST OF TODAY`S MODEL RUNS WHICH WOULD SHUT
OFF PRECIPITATION BY LATE MONDAY OR MONDAY NIGHT. THE GOOD NEWS IS
THAT IF HEAVY RAIN DOES DEVELOP IT APPEARS THERE WILL BE SOME
SHIFTING BETWEEN THE CASCADES OF WRN WA/WRN OREGON. THIS SHOULD
LIMIT POTENTIAL QPF IN ANY ONE PARTICULAR AREA. MODELS NOW SHOW 24
TO 36 HOUR QPF AMOUNTS OF 4 TO 6 INCHES MORE EVENLY DISTRIBUTED
ALONG THE WA/OREGON CASCADES. THIS IS STILL ENOUGH FOR SOME MINOR
FLOODING ON THE MORE PRONE RIVERS SO FORECASTS SHOULD BE MONITORED
CLOSELY.

ANOTHER SURFACE LOW WILL TRACK INTO WRN WA OR NRN OREGON AROUND
TUESDAY. MODELS NO LONGER TAP THIS LOW FOR A CONTINUOUS MOISTURE
STREAM WHICH INSTEAD ARRIVES AFTER A BREAK IN RAINFALL. MODELS ARE
ALSO TRENDING MUCH WEAKER WITH THIS LOW SO ADDITIONAL RAIN AMOUNTS
LOOK TO BE LIGHT AND NOT HYDROLOGICALLY SIGNIFICANT.

LONG RANGE MODELS ARE INDICATING A POSSIBLE PATTERN CHANGE BY THE
MIDDLE OF NEXT WEEK. HOWEVER...MODELS DIFFER ON THE POSITIONING OF A
HIGH OVER KONA LOW PATTERN OVER THE PACIFIC WHICH WILL DETERMINE THE
STRENGTH OF NLY FLOW OVER WRN WA. THE 12/18Z GFS IS FURTHER E WITH
THE LOW AND DUMPS MOST THE COLD AIR INTO THE ROCKIES. COLDER AIR
WOULD ARRIVE ACROSS WRN WA IF THE ECMWF SOLUTION VERIFIED WITH THE
LOW FURTHER W. EITHER WAY...A TRANSITION TO COOLER TEMPERATURES IS
LIKELY ENOUGH TO TREND HIGH/LOW TEMPS DOWNWARD A BIT FOR WEDNESDAY.
MERCER

&&

.HYDROLOGY...RIVER FLOODING IS NOT EXPECTED THROUGH SATURDAY. A
MOIST WESTERLY FLOW PATTERN WILL DEVELOP SATURDAY NIGHT AND CONTINUE
THROUGH SUNDAY NIGHT WITH HEAVY RAIN AT TIMES IN THE MOUNTAINS. THE
LATEST 12Z GFS/ECMWF ARE FASTER WITH THE TRAILING FRONTAL BAND AND
PUSHES IT SWD INTO OREGON BY MONDAY. THIS COULD HELP MITIGATE ANY
RIVER FLOODING THAT DEVELOPS BUT DOES NOT END THE THREAT AS MODELS
HAVE NOT ALL SETTLED ON A PARTICULAR SOLUTION. 24 TO 36 HOUR RAIN
AMOUNTS ARE STILL AVERAGING ABOUT 4 TO 5 INCHES OVER THE WA CASCADES
WHICH COULD CAUSE FLOODING ON PRONE RIVERS. AT THIS TIME...PRIMARY
CONCERN FOR ANY RIVER RISING ABOVE FLOOD STAGE IS THE SKOKOMISH BUT
ALSO NEED TO KEEP AN EYE ON OTHER CASCADE FLOOD PRONE STREAMS. MERCER

&&

.AVIATION...A STRETCHED OUT AND WEAKENING UPPER LEVEL TROUGH ALONG
THE COAST WILL MOVE ONSHORE TONIGHT. A STRONG PACIFIC FRONT
APPROACHING 140W THIS AFTERNOON WILL APPROACH THE COASTAL WATERS
THURSDAY AFTERNOON. AT THE SURFACE...HIGH PRES E OF THE CASCADES
COMBINED WITH LOWER PRES OVER THE COASTAL WATERS IS GIVING LIGHT
OFFSHORE FLOW. FLOW WILL BECOME LIGHT TO WEAKLY ONSHORE TONIGHT AS
THE TROUGH OFF THE COAST MOVES INLAND. FLOW ALOFT IS LIGHT SWLY AND
IS MOIST AND STABLE.

PACIFIC NW RADARS CONTINUE TO SHOW BANDS OF LIGHT RAIN SHOWERS
EXTENDING FROM THE NORTH INTERIOR SOUTHWESTWARD TO THE NORTHWEST
OREGON COASTAL WATERS. THIS MOISTURE IS MOVING NE AHEAD OF THE
INCOMING WEAKENING TROUGHS OFFSHORE. MOST TERMINALS IN THE INTERIOR
ARE SEEING VFR CEILINGS AND VISIBILITIES DESPITE THE LIGHT RAIN AS A
RESULT OF THE OFFSHORE PRES GRADIENTS. THE EXCEPTIONS ARE ON THE
NORTH COAST WHERE MVFR CONDITIONS ARE OCCURRING AND AT KOLM WHERE
SOME SCT-BKN006 IS PRODUCING OCCASIONAL IFR CONDITIONS THIS
AFTERNOON. WITH PRES GRADIENTS CONTINUING TO RELAX
OVERNIGHT...EXPECT CEILINGS TO BECOME MOSTLY MVFR LATER THIS EVENING
THROUGH THU MORNING. LOCAL IFR CONDITIONS CAN BE EXPECTED IN THE S
INTERIOR LATE TONIGHT INTO THU MORNING. ALBRECHT

KSEA...EXPECT CIGS AROUND 045 THROUGH THIS EVENING WITH PERIODS OF
LIGHT RAIN. CEILINGS WILL FALL TO 015-020 AFTER 05Z THIS EVENING AND
CONTINUE UNTIL 18Z. SOME IMPROVEMENT CAN BE EXPECTED THU AFTERNOON
AS OFFSHORE PRES GRADIENTS INCREASE IN RESPONSE TO THE NEXT
APPROACHING FRONT. LIGHT SE WINDS GENERALLY LESS THAN 6 KT. ALBRECHT

&&

.MARINE...A WEAK TROUGH OF LOW PRES OVER THE COASTAL WATERS WILL
MOVE INLAND OVERNIGHT. EXPECT LIGHT FLOW. SEAS OVER THE COASTAL
WATERS ARE EXPECTED TO DIMINISH TO BELOW 10 FEET LATE THIS
AFTERNOON...SO THE SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FOR THE
COASTAL WATERS AND THE SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR
BAR WILL BE ALLOWED TO EXPIRE.

A STRONG PACIFIC FRONT ASSOCIATED WITH A 960 MB LOW CENTERED NEAR
50N 156W IS APPROACHING 142W THIS AFTERNOON. THIS FRONT WILL MOVE
THROUGH THE OFFSHORE WATERS ON THU...THEN MOVE INLAND THU NIGHT. A
PERIOD OF GALE FORCE WINDS CAN BE EXPECTED OVER THE COASTAL WATERS
THU AFTERNOON THRU THU NIGHT AHEAD OF AND WITH THE FRONT. THE GALE
WATCH FOR THE COASTAL WATERS WAS UPGRADED TO A GALE WARNING. EXPECT
SMALL CRAFT ADVISORY CONDITIONS LATER THURSDAY OR THURSDAY NIGHT AT
THE ENTRANCES TO THE STRAIT OF JUAN DE FUCA...THE NORTHERN INLAND
WATERS...AND ADMIRALTY INLET.

THE FETCH AREA TO THE SOUTH OF THE LOW NEAR 50N 156W IS MOVING WITH
THE WAVE FIELD IT IS PRODUCING. THE WAVEWATCH MODEL CONTINUES TO
FORECAST SEAS NEAR 45 FT TO THE S OF THIS LOW TONIGHT...AND THESE
WAVES ARE EXPECTED TO DECAY INTO AN ENERGETIC 22 FT AT 20 SEC SWELL
ON THE WASHINGTON COAST LATE FRI AFTERNOON AND FRI NIGHT. AS IT
TURNS OUT...TIDAL ANOMALIES ALONG THE COAST ARE JUST OVER 1 FT ABOVE
NORMAL AND HIGH TIDE OCCURS SAT MORNING. IF SWELL REMAINS HIGH INTO
SAT MORNING AS CURRENTLY EXPECTED...SOME COASTAL FLOODING IS
POSSIBLE ALONG PORTIONS OF THE COASTAL WATERS AROUND HIGH TIDE ON
SATURDAY. IT IS TOO EARLY TO TELL AT THIS POINT AND TOO EARLY TO
ISSUE ANY COASTAL FLOOD WATCHES...BUT INTERESTS ON THE COAST ARE
URGED TO KEEP UP WITH LATEST FORECASTS.

ANOTHER STRONG WARM FRONT WILL ARRIVE ON SAT AND WILL LIKELY RESULT
IN A PERIOD OF GALE FORCE WINDS OVER THE COASTAL WATERS...THE NORTH
INLAND WATERS...AND THE ENTRANCES TO THE STRAIT OF JUAN DE FUCA.
THEN ONSHORE FLOW WILL SLOWLY EASE ON SUN. ALBRECHT

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS COASTAL WATERS UNTIL 4
      PM PST THIS AFTERNOON.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR UNTIL 4 PM
      PST THIS AFTERNOON.
     GALE WARNING THURSDAY AND THURSDAY NIGHT COASTAL WATERS.

&&

$$

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML














000
FXUS66 KSEW 172249
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 PM PST WED DEC 17 2014

.SYNOPSIS...A WEAK FRONT WILL DISSIPATE OVER THE REGION TONIGHT AND
EARLY THURSDAY. THE NEXT STRONGER PACIFIC FRONTAL SYSTEM WILL MOVE
ASHORE THURSDAY NIGHT WITH MORE SIGNIFICANT RAIN AND SOME MOUNTAIN
SNOW. ANOTHER WET WEATHER SYSTEM IS FORECAST FOR THIS WEEKEND WITH
HEAVIER RAIN AMOUNTS ALONG THE COAST AND IN THE MOUNTAINS. COOLER
AND MORE SHOWERY WEATHER MAY DEVELOP BY THE MIDDLE OF NEXT WEEK.

&&

.SHORT TERM...MOIST SW FLOW ALOFT CONTINUES OVER THE PAC NW AHEAD OF
AN APPROACHING SPLIT NRN STREAM TROUGH. PRECIPITATION WAS LIGHT
TODAY WITH MOST SPOTS RECEIVING LESS THAN ONE TENTH OF AN INCH. THE
NEXT BATCH OF RAIN WILL ALSO BE LIGHT THIS EVENING WITH JUST MINOR
MEASURABLE AMOUNTS FOR MOST PLACES. SATELLITE IMAGERY SHOWS MORE
PRONOUNCED SPLITTING OF THE FRONTAL BAND STARTING TO MOVE INLAND.
HRRR AND NAM12 MODELS STILL KEEP LIGHT RAIN AROUND THE AREA...AT
LEAST THROUGH THE EVENING HOURS BEFORE DECREASING. WILL MAINTAIN THE
CHANCE POPS WITH MORE UNCERTAINTY THAN USUAL FOR THE FIRST PERIOD
FORECAST.

LIGHT SHOWERS MAY LINGER INTO THURSDAY MORNING BUT AN UPPER LEVEL
RIDGE WILL BE MOVING ACROSS WRN WA DURING THE DAY. THE NAM12 SHOWS
SOME LIGHT SPOTTY QPF OVER THE AREA UNTIL THE NEXT STRONGER FRONTAL
SYSTEM ARRIVES LATER IN THE DAY. CONSIDERATION WAS GIVEN TO DRYING
OUT THE MORNING PERIOD FOR INLAND AREAS BUT GIVEN THE NAM12...SOME
LIGHT PRECIPITATION CANNOT BE RULED OUT AND CHANCE POPS WILL BE
MAINTAINED.

MODELS AGREE THAT RAIN WILL DEVELOP ON THE COAST LATE IN THE DAY
WITH A WEAK WARM FRONTAL FEATURE. THE TRAILING COLD FRONT WILL
QUICKLY FOLLOW...PUSHING THROUGH WRN WA THURSDAY NIGHT. THIS SYSTEM
WILL BRING MORE RAIN THAN PREVIOUS SYSTEMS AND ALSO SOME COOLER AIR
WITH LOWERING SNOW LEVELS. A FEW INCHES OF SNOW ARE STILL EXPECTED
IN THE MOUNTAINS ABOVE ABOVE 4000 FEET ONCE THE SNOW LEVELS DROPS
OFF THURSDAY NIGHT. ABOVE 5500 FEET...UP TO 6 INCHES COULD
FALL...MAINLY ALONG S/SW FACING SLOPES OF MOUNT BAKER AND MOUNT
RAINIER.

RAIN WILL CHANGE OVER TO SHOWERS IN THE LOWLANDS FRIDAY AND SNOW
WILL TAPER OFF IN THE MOUNTAINS. A LULL IN PRECIPITATION IS EXPECTED
BETWEEN STORM SYSTEMS POSSIBLY THROUGH MUCH OF FRIDAY NIGHT BUT
MODELS DIFFER SLIGHTLY ON THE TIMING OF THE NEXT FRONT.

MODELS HOW A STRONG WARM FRONT TO SPREAD RAIN INTO WRN WA BY
SATURDAY MORNING. A MOIST WESTERLY FLOW PATTERN WILL BE DIRECTED
INTO WRN WA/WRN OREGON BY SATURDAY NIGHT AND SUNDAY. THE 12Z ECMWF
HAS TRENDED TOWARD THE PAST 2-3 GFS40 RUNS SAGGING THE MOISTURE PLUM
SWD ON SUNDAY AFTERNOON. THIS WOULD SHIFT HEAVIER MOUNTAIN RAIN INTO
THE CASCADES OF SRN WA/AND OREGON WITH LIGHTER FURTHER N OVER THE
CENTRAL/N WA CASCADES. WHILE MODELS HAVE TRENDED TOWARD LESS
PRECIPITATION OVER THE WA CASCADES THE MODELS HAVE YET TO LATCH ON
TO ONE PARTICULAR SOLUTION SO UNCERTAINTY REMAINS HIGH ON WHERE THE
HEAVIEST RAIN WILL FALL. SEE THE HYDRO DISCUSSION BELOW FOR FURTHER
DETAILS.

.LONG TERM...MODELS NOW SHOW A BREAK OR AT LEAST DECREASE IN
RAINFALL RATES SUNDAY NIGHT AS WEAK HIGH PRESSURE TEMPORARILY BUILDS
OFFSHORE. THE RIDGE WILL LIFT THE FLOW NWD SO MOISTURE DIRECTED INTO
SRN WA/OREGON WILL LIFT BACK OVER WRN WA ON MONDAY. THE RIDGING IS
QUITE A BIT STRONGER ON MOST OF TODAY`S MODEL RUNS WHICH WOULD SHUT
OFF PRECIPITATION BY LATE MONDAY OR MONDAY NIGHT. THE GOOD NEWS IS
THAT IF HEAVY RAIN DOES DEVELOP IT APPEARS THERE WILL BE SOME
SHIFTING BETWEEN THE CASCADES OF WRN WA/WRN OREGON. THIS SHOULD
LIMIT POTENTIAL QPF IN ANY ONE PARTICULAR AREA. MODELS NOW SHOW 24
TO 36 HOUR QPF AMOUNTS OF 4 TO 6 INCHES MORE EVENLY DISTRIBUTED
ALONG THE WA/OREGON CASCADES. THIS IS STILL ENOUGH FOR SOME MINOR
FLOODING ON THE MORE PRONE RIVERS SO FORECASTS SHOULD BE MONITORED
CLOSELY.

ANOTHER SURFACE LOW WILL TRACK INTO WRN WA OR NRN OREGON AROUND
TUESDAY. MODELS NO LONGER TAP THIS LOW FOR A CONTINUOUS MOISTURE
STREAM WHICH INSTEAD ARRIVES AFTER A BREAK IN RAINFALL. MODELS ARE
ALSO TRENDING MUCH WEAKER WITH THIS LOW SO ADDITIONAL RAIN AMOUNTS
LOOK TO BE LIGHT AND NOT HYDROLOGICALLY SIGNIFICANT.

LONG RANGE MODELS ARE INDICATING A POSSIBLE PATTERN CHANGE BY THE
MIDDLE OF NEXT WEEK. HOWEVER...MODELS DIFFER ON THE POSITIONING OF A
HIGH OVER KONA LOW PATTERN OVER THE PACIFIC WHICH WILL DETERMINE THE
STRENGTH OF NLY FLOW OVER WRN WA. THE 12/18Z GFS IS FURTHER E WITH
THE LOW AND DUMPS MOST THE COLD AIR INTO THE ROCKIES. COLDER AIR
WOULD ARRIVE ACROSS WRN WA IF THE ECMWF SOLUTION VERIFIED WITH THE
LOW FURTHER W. EITHER WAY...A TRANSITION TO COOLER TEMPERATURES IS
LIKELY ENOUGH TO TREND HIGH/LOW TEMPS DOWNWARD A BIT FOR WEDNESDAY.
MERCER

&&

.HYDROLOGY...RIVER FLOODING IS NOT EXPECTED THROUGH SATURDAY. A
MOIST WESTERLY FLOW PATTERN WILL DEVELOP SATURDAY NIGHT AND CONTINUE
THROUGH SUNDAY NIGHT WITH HEAVY RAIN AT TIMES IN THE MOUNTAINS. THE
LATEST 12Z GFS/ECMWF ARE FASTER WITH THE TRAILING FRONTAL BAND AND
PUSHES IT SWD INTO OREGON BY MONDAY. THIS COULD HELP MITIGATE ANY
RIVER FLOODING THAT DEVELOPS BUT DOES NOT END THE THREAT AS MODELS
HAVE NOT ALL SETTLED ON A PARTICULAR SOLUTION. 24 TO 36 HOUR RAIN
AMOUNTS ARE STILL AVERAGING ABOUT 4 TO 5 INCHES OVER THE WA CASCADES
WHICH COULD CAUSE FLOODING ON PRONE RIVERS. AT THIS TIME...PRIMARY
CONCERN FOR ANY RIVER RISING ABOVE FLOOD STAGE IS THE SKOKOMISH BUT
ALSO NEED TO KEEP AN EYE ON OTHER CASCADE FLOOD PRONE STREAMS. MERCER

&&

.AVIATION...A STRETCHED OUT AND WEAKENING UPPER LEVEL TROUGH ALONG
THE COAST WILL MOVE ONSHORE TONIGHT. A STRONG PACIFIC FRONT
APPROACHING 140W THIS AFTERNOON WILL APPROACH THE COASTAL WATERS
THURSDAY AFTERNOON. AT THE SURFACE...HIGH PRES E OF THE CASCADES
COMBINED WITH LOWER PRES OVER THE COASTAL WATERS IS GIVING LIGHT
OFFSHORE FLOW. FLOW WILL BECOME LIGHT TO WEAKLY ONSHORE TONIGHT AS
THE TROUGH OFF THE COAST MOVES INLAND. FLOW ALOFT IS LIGHT SWLY AND
IS MOIST AND STABLE.

PACIFIC NW RADARS CONTINUE TO SHOW BANDS OF LIGHT RAIN SHOWERS
EXTENDING FROM THE NORTH INTERIOR SOUTHWESTWARD TO THE NORTHWEST
OREGON COASTAL WATERS. THIS MOISTURE IS MOVING NE AHEAD OF THE
INCOMING WEAKENING TROUGHS OFFSHORE. MOST TERMINALS IN THE INTERIOR
ARE SEEING VFR CEILINGS AND VISIBILITIES DESPITE THE LIGHT RAIN AS A
RESULT OF THE OFFSHORE PRES GRADIENTS. THE EXCEPTIONS ARE ON THE
NORTH COAST WHERE MVFR CONDITIONS ARE OCCURRING AND AT KOLM WHERE
SOME SCT-BKN006 IS PRODUCING OCCASIONAL IFR CONDITIONS THIS
AFTERNOON. WITH PRES GRADIENTS CONTINUING TO RELAX
OVERNIGHT...EXPECT CEILINGS TO BECOME MOSTLY MVFR LATER THIS EVENING
THROUGH THU MORNING. LOCAL IFR CONDITIONS CAN BE EXPECTED IN THE S
INTERIOR LATE TONIGHT INTO THU MORNING. ALBRECHT

KSEA...EXPECT CIGS AROUND 045 THROUGH THIS EVENING WITH PERIODS OF
LIGHT RAIN. CEILINGS WILL FALL TO 015-020 AFTER 05Z THIS EVENING AND
CONTINUE UNTIL 18Z. SOME IMPROVEMENT CAN BE EXPECTED THU AFTERNOON
AS OFFSHORE PRES GRADIENTS INCREASE IN RESPONSE TO THE NEXT
APPROACHING FRONT. LIGHT SE WINDS GENERALLY LESS THAN 6 KT. ALBRECHT

&&

.MARINE...A WEAK TROUGH OF LOW PRES OVER THE COASTAL WATERS WILL
MOVE INLAND OVERNIGHT. EXPECT LIGHT FLOW. SEAS OVER THE COASTAL
WATERS ARE EXPECTED TO DIMINISH TO BELOW 10 FEET LATE THIS
AFTERNOON...SO THE SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FOR THE
COASTAL WATERS AND THE SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR
BAR WILL BE ALLOWED TO EXPIRE.

A STRONG PACIFIC FRONT ASSOCIATED WITH A 960 MB LOW CENTERED NEAR
50N 156W IS APPROACHING 142W THIS AFTERNOON. THIS FRONT WILL MOVE
THROUGH THE OFFSHORE WATERS ON THU...THEN MOVE INLAND THU NIGHT. A
PERIOD OF GALE FORCE WINDS CAN BE EXPECTED OVER THE COASTAL WATERS
THU AFTERNOON THRU THU NIGHT AHEAD OF AND WITH THE FRONT. THE GALE
WATCH FOR THE COASTAL WATERS WAS UPGRADED TO A GALE WARNING. EXPECT
SMALL CRAFT ADVISORY CONDITIONS LATER THURSDAY OR THURSDAY NIGHT AT
THE ENTRANCES TO THE STRAIT OF JUAN DE FUCA...THE NORTHERN INLAND
WATERS...AND ADMIRALTY INLET.

THE FETCH AREA TO THE SOUTH OF THE LOW NEAR 50N 156W IS MOVING WITH
THE WAVE FIELD IT IS PRODUCING. THE WAVEWATCH MODEL CONTINUES TO
FORECAST SEAS NEAR 45 FT TO THE S OF THIS LOW TONIGHT...AND THESE
WAVES ARE EXPECTED TO DECAY INTO AN ENERGETIC 22 FT AT 20 SEC SWELL
ON THE WASHINGTON COAST LATE FRI AFTERNOON AND FRI NIGHT. AS IT
TURNS OUT...TIDAL ANOMALIES ALONG THE COAST ARE JUST OVER 1 FT ABOVE
NORMAL AND HIGH TIDE OCCURS SAT MORNING. IF SWELL REMAINS HIGH INTO
SAT MORNING AS CURRENTLY EXPECTED...SOME COASTAL FLOODING IS
POSSIBLE ALONG PORTIONS OF THE COASTAL WATERS AROUND HIGH TIDE ON
SATURDAY. IT IS TOO EARLY TO TELL AT THIS POINT AND TOO EARLY TO
ISSUE ANY COASTAL FLOOD WATCHES...BUT INTERESTS ON THE COAST ARE
URGED TO KEEP UP WITH LATEST FORECASTS.

ANOTHER STRONG WARM FRONT WILL ARRIVE ON SAT AND WILL LIKELY RESULT
IN A PERIOD OF GALE FORCE WINDS OVER THE COASTAL WATERS...THE NORTH
INLAND WATERS...AND THE ENTRANCES TO THE STRAIT OF JUAN DE FUCA.
THEN ONSHORE FLOW WILL SLOWLY EASE ON SUN. ALBRECHT

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS COASTAL WATERS UNTIL 4
      PM PST THIS AFTERNOON.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR UNTIL 4 PM
      PST THIS AFTERNOON.
     GALE WARNING THURSDAY AND THURSDAY NIGHT COASTAL WATERS.

&&

$$

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML















000
FXUS66 KPQR 171756
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
954 AM PST WED DEC 17 2014

.SYNOPSIS...A CLOSED LOW JUST OFFSHORE WEST OF THE OR/CA BORDER WILL
SLOWLY WEAKEN AND EVENTUALLY MOVE ONSHORE ALONG THE N OR/S WA COAST
THIS AFTERNOON. THIS WILL MAINTAIN LIGHT SHOWER ACTIVITY...MAINLY
OVER THE HIGHER TERRAIN THIS MORNING. AN UPPER LEVEL SHORTWAVE WILL
PUSH ONSHORE LATER TODAY...LIKELY BRINGING A PERIOD OF STEADIER
RAINFALL THROUGH EARLY THU MORNING. EXPECT A FAIRLY QUIET PERIOD FOR
MUCH OF THE DAY THU...BUT THEN A MORE ORGANIZED FRONT WILL BRING
GUSTY WINDS AND LARGE SURF TO THE COAST AND RAIN SPREADING INLAND
THURSDAY NIGHT AND FRIDAY. RISING SNOW LEVELS WILL LIMIT SNOW TO THE
HIGHEST PEAKS...BUT COLDER AIR BEHIND THE FRONT MAY RESULT IN SOME
SNOW SHOWERS FOR THE CASCADES PASSES FRIDAY EVENING AND SATURDAY.
WARMER AND MOISTER WEATHER IS EXPECTED THIS WEEKEND. THERE IS THE
POTENTIAL FOR AN ATMOSPHERIC RIVER TYPE SET UP AND ASSOCIATED HEAVY
RAIN TO DEVELOP OVER THE WEEKEND INTO EARLY NEXT WEEK.

&&

.UPDATE...SUBTLE CHANGES FOR TODAY MAINLY BY INCREASING POPS FOR THE
AFTERNOON...AND LATE AFTERNOON PROBABLY IN REALITY. ALSO PLAN ON
RAMPING UP COAST RANGE AND CASCADE WINDS FOR THE NEXT FRONTAL SYSTEM
MAINLY LATE THURSDAY AFTERNOON AND THURSDAY NIGHT. NOT ANTICIPATING
ANY HIGHLIGHTS BUT PROBABLY A RUN OF THE MILL WINDY COASTAL STORM.

MAIN ATTENTION WILL BE PLACED ON THE ATMOSPHERIC RIVER EVENT SETTING
UP TO AFFECT THE REGION THIS WEEKEND WITH IMPACTS LASTING INTO NEXT
WEEK. RAW GFS MODEL RUN ACCUMULATED QPF AMOUNTS EXCEED 12 INCHES FOR
PORTIONS OF THE CASCADES AND 10 INCHES FOR THE COAST RANGE ENDING
MONDAY MORNING. MOST OF THAT OCCURS BEGINNING SATURDAY. THERE WOULD
BE DEEP WESTERLY FLOW FROM THE SURFACE UP TO THE JET LEVEL THUS
EXPECT THIS COULD BE AN IDEAL SITUATION TO EXTRACT A MAXIMUM AMOUNT
OF RAIN FROM WHATEVER COMES ASHORE. THERE IS GENERAL LARGE SCALE
SUPPORT FROM THE ECMWF ALBEIT WITH LESS QPF. PAST EXPERIENCE SHOWS
FOLLOWING THE HIGHER GFS QPF AMOUNTS IS STILL NOT ENOUGH AND THAT
REALITY BRINGS SIGNIFICANTLY MORE RAIN. ASSUMING THE CURRENT MODEL
RUNS STAY UNCHANGED IN THE FUTURE...WOULD EXPECT MULTIPLE MAINSTEM
RIVERS EXCEEDING FLOOD STAGE AS SOON AS SUNDAY MORNING.

WILL BEGIN TO ISSUE SOME OUTLOOK PRODUCTS TODAY WITH THE CAVEAT THAT
MODELS HAVE RELATIVELY RECENTLY SHIFTED THE FOCUS FROM NORTHERN
WASHINGTON/BRITISH COLUMBIA SOUTH TO OUR AREA. ADDITIONAL SHIFTING
IS EXPECTED AS WELL AS TIMING DIFFERENCES. STAY TUNED AS THIS
SITUATION EVOLVES OVER TIME. /JBONK

&&

.PREV DISC... /ISSUED 259 AM PST WED DEC 17 2014/

SHORT TERM...TODAY THROUGH SATURDAY...VERY LIGHT RAIN CONTINUES TO
IMPACT SW WASHINGTON THIS MORNING BUT HAS OTHERWISE STARTED TO
DISSIPATE OVER THE SOUTHERN PORTION OF THE FORECAST AREA. WATER
VAPOR IMAGERY SHOWS A CLOSED LOW WEAKENING AS IT HAS PUSHED ONSHORE
NEAR THE OREGON/CALIFORNIA BORDER...WHILE AN UPPER LEVEL SHORTWAVE
IS ELONGATING AS IT APPROACHES THE PACIFIC NORTHWEST COASTLINE. NOT
MUCH CHANGE IN THE KTTD-KDLS GRADIENT...WHICH REMAINS AROUND -5
EARLY THIS MORNING. EAST WINDS CONTINUE TO GUST NEAR 25 MPH THROUGH
THE GORGE...BUT EXPECT THE EASTERLY GRADIENT TO WEAKEN BY LATE
TONIGHT.

AFTER A PERIOD OF LIGHT RAIN THIS MORNING...MODELS REMAIN CONSISTENT
IN SHOWING AN UPTICK IN PRECIP BY THIS AFTERNOON ASSOCIATED WITH THE
VORT MAX JUST OFFSHORE AROUND 45N 134W. THE LOWER LEVEL MOISTURE
ASSOCIATED WITH THE SURFACE LOW COMBINED WITH THE UPPER LEVEL FORCING
FROM THE SHORTWAVE SHOULD DRIVE A PERIOD OF STEADIER PRECIP THIS
EVENING AND THROUGH TONIGHT. THE VORT MAX PUSHES EAST OF THE CASCADES
BY 12Z THU...AFTER WHICH SHOWER ACTIVITY SHOULD DROP OFF
SIGNIFICANTLY.

WITH CLEARING SKIES AND LIGHT WINDS...SHOULD SEE SOME SHALLOW FOG TO
DEVELOP IN INTERIOR VALLEYS TONIGHT THROUGH EARLY THU MORNING. MODELS
MAINTAIN A THREAT FOR LIGHT PRECIP OVER THE HIGHER TERRAIN MUCH OF
THU...BUT OTHERWISE EXPECT DRY CONDITIONS TO PERSIST TO LOWER
ELEVATIONS. THE NEXT SIGNIFICANT FRONTAL SYSTEM ARRIVES LATE
THU...SPREADING RAIN AND BRINGING GUSTY COASTAL WINDS TO THE REGION
THROUGH FRI. PRECIPITABLE WATER IS EXPECTED TO BE NEAR AN INCH AND AN
APPROACHING JET STREAK SHOULD PROVIDE GOOD LIFT AND EXPECT THE
HIGHEST RAINFALL TOTALS OF 0.75 TO 1 INCH ACROSS THE COAST AND COAST
RANGE THROUGH MIDDAY FRI. OTHER LOCATIONS WILL SEE ON AVERAGE 0.5
INCHES OF RAIN. SNOW LEVELS SHOULD REMAIN ABOVE 5000 FEET DURING THE
PEAK RAIN PERIOD...BUT LOWER TO NEAR OR BELOW THE CASCADE PASSES
BEHIND THE FRONT FRIDAY AFTERNOON.

STRONG LOW PRESSURE OVER THE GULF OF ALASKA WILL PUSH INLAND LATE FRI
INTO EARLY SAT MORNING...SIMULTANEOUSLY FLATTENING A BROAD AREA OF
HIGH PRESSURE OVER THE EASTERN PACIFIC. THERE IS INCREASING
CONFIDENCE AN ATMOSPHERIC RIVER SCENARIO WILL SET UP...WITH ABUNDANT
MOISTURE AIMED DIRECTLY AT THE PACIFIC NORTHWEST SAT.

LONG TERM...SATURDAY NIGHT THROUGH TUESDAY...AS THIS TROUGH MOVES ON
SHORE SATURDAY...THE ASSOCIATED COLD FRONT MOVES ONSHORE AND STALLS
EAST-TO-WEST ACROSS NORTHWEST OREGON AND SOUTHWEST WASHINGTON. THIS
PUTS OUR AREA IN THE PATH OF RAIN STARTING SATURDAY THROUGH MONDAY.
SOME UNCERTAINTY EXISTS IN WHERE THIS BOUNDARY WILL SET UP...WHICH
WILL DETERMINE HOW MUCH RAINFALL WE WILL GET. ON TUESDAY...GEFS
ENSEMBLE SPAGHETTI PLOTS GET MESSY AND SIGNIFICANT DIFFERENCES START
TO SHOW UP BETWEEN THE GFS AND ECMWF...DECREASING CONFIDENCE ON HOW
THE REST OF THE WEEK WILL SHAPE UP.  AS OF NOW...THE MOST COMMON
SOLUTION IS THAT HIGH PRESSURE RIDGING WILL START TO BUILD BACK OVER
THE WESTERN U.S. WHICH SUGGESTS DRIER WEATHER STARTING TUESDAY...
THOUGH UNCERTAINTY IS VERY HIGH. -MCCOY

&&

.AVIATION...VFR CONDITIONS TO PERSIST AT MOST TAF SITES THROUGH
THIS AFTERNOON. AS SHOWERS MOVE IN...THERE MAY BE PERIODS OF
MVFR...ESPECIALLY AT SOUTH WILLAMETTE VALLEY SITES. CLEARING IS
POSSIBLE THIS EVENING...ALLOWING FOG TO DEVELOP IFR CIGS AND
VIS...BUT UNCERTAINTY IS HIGH BECAUSE THE MODELS ARE HINTING AT A
WEAK LOW PRESSURE SYSTEM OFF THE SOUTH OREGON COAST MOVING INLAND
THIS EVENING. THIS COULD BRING ADDITIONAL SHOWERS AND WINDS WHICH
WOULD KEEP CIGS VFR/MVFR. IF ANY CLEARING DOES OCCUR...EXPECT CIGS
AND VIS TO DROP TO IFR WITH THE DEVELOPMENT OF FOG/LOW STRATUS.

KPDX AND APPROACHES...VFR CONDITIONS TO PERSIST WEDNESDAY.
RAIN MAY BRING PERIODS OF MVFR CIGS AND VIS. CIGS COULD DROP TO
IFR TONIGHT WITH THE DEVELOPMENT OF FOG/LOW STRATUS AFTER 09Z
THURSDAY. -MCCOY

&&

.MARINE...WEST SWELL AROUND 10 FT BRINGING SEAS UP TO SMALL CRAFT
CRITERIA TODAY. SEAS DROP BELOW 10 FT LATER THIS EVENING. THE
SYSTEM OF INTEREST WILL BE TOMORROW WHICH WILL LIKELY BRING
SOUTHERLY GALES THROUGH EARLY FRIDAY. THERE IS STILL SOME
UNCERTAINTY ON TIMING...BUT MODELS ARE COMING INTO AGREEMENT THAT
WINDS WILL START TO INCREASE EARLY THURSDAY MORNING...REACHING
GALE FORCE BY EARLY AFTERNOON. SEAS BUILD INTO THE TEENS THURSDAY
AFTERNOON. SEAS DROP BACK DOWN TO 10 TO 12 FT ON FRIDAY AHEAD OF
THE NEXT SYSTEM WHICH WILL BRING SEAS UP EVEN HIGHER ON SATURDAY.

THERE IS STILL UNCERTAINTY ON THE TIMING OF THE SATURDAY SYSTEM...BUT
AS OF NOW MODELS ARE SUGGESTING THAT WINDS COULD AGAIN REACH GALE
FORCE EARLY SATURDAY...WHICH COULD BUILD SEAS INTO THE LOW 20S.
SEAS START TO FALL EARLY SUNDAY...DROPPING BACK INTO THE LOW
TEENS BY LATE SUNDAY OR EARLY MONDAY. AN ACTIVE WEATHER PATTERN
WILL CONTINUE THROUGH THIS WEEKEND...KEEPING SEAS ELEVATED
THROUGH EARLY NEXT WEEK WITH PERIODS OF GALES POSSIBLE. -MCCOY


&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...GALE WATCH FROM THURSDAY MORNING THROUGH THURSDAY EVENING FOR
     COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 9 PM PST THIS
     EVENING FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 4 PM PST THIS AFTERNOON.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.




000
FXUS66 KPQR 171756
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
954 AM PST WED DEC 17 2014

.SYNOPSIS...A CLOSED LOW JUST OFFSHORE WEST OF THE OR/CA BORDER WILL
SLOWLY WEAKEN AND EVENTUALLY MOVE ONSHORE ALONG THE N OR/S WA COAST
THIS AFTERNOON. THIS WILL MAINTAIN LIGHT SHOWER ACTIVITY...MAINLY
OVER THE HIGHER TERRAIN THIS MORNING. AN UPPER LEVEL SHORTWAVE WILL
PUSH ONSHORE LATER TODAY...LIKELY BRINGING A PERIOD OF STEADIER
RAINFALL THROUGH EARLY THU MORNING. EXPECT A FAIRLY QUIET PERIOD FOR
MUCH OF THE DAY THU...BUT THEN A MORE ORGANIZED FRONT WILL BRING
GUSTY WINDS AND LARGE SURF TO THE COAST AND RAIN SPREADING INLAND
THURSDAY NIGHT AND FRIDAY. RISING SNOW LEVELS WILL LIMIT SNOW TO THE
HIGHEST PEAKS...BUT COLDER AIR BEHIND THE FRONT MAY RESULT IN SOME
SNOW SHOWERS FOR THE CASCADES PASSES FRIDAY EVENING AND SATURDAY.
WARMER AND MOISTER WEATHER IS EXPECTED THIS WEEKEND. THERE IS THE
POTENTIAL FOR AN ATMOSPHERIC RIVER TYPE SET UP AND ASSOCIATED HEAVY
RAIN TO DEVELOP OVER THE WEEKEND INTO EARLY NEXT WEEK.

&&

.UPDATE...SUBTLE CHANGES FOR TODAY MAINLY BY INCREASING POPS FOR THE
AFTERNOON...AND LATE AFTERNOON PROBABLY IN REALITY. ALSO PLAN ON
RAMPING UP COAST RANGE AND CASCADE WINDS FOR THE NEXT FRONTAL SYSTEM
MAINLY LATE THURSDAY AFTERNOON AND THURSDAY NIGHT. NOT ANTICIPATING
ANY HIGHLIGHTS BUT PROBABLY A RUN OF THE MILL WINDY COASTAL STORM.

MAIN ATTENTION WILL BE PLACED ON THE ATMOSPHERIC RIVER EVENT SETTING
UP TO AFFECT THE REGION THIS WEEKEND WITH IMPACTS LASTING INTO NEXT
WEEK. RAW GFS MODEL RUN ACCUMULATED QPF AMOUNTS EXCEED 12 INCHES FOR
PORTIONS OF THE CASCADES AND 10 INCHES FOR THE COAST RANGE ENDING
MONDAY MORNING. MOST OF THAT OCCURS BEGINNING SATURDAY. THERE WOULD
BE DEEP WESTERLY FLOW FROM THE SURFACE UP TO THE JET LEVEL THUS
EXPECT THIS COULD BE AN IDEAL SITUATION TO EXTRACT A MAXIMUM AMOUNT
OF RAIN FROM WHATEVER COMES ASHORE. THERE IS GENERAL LARGE SCALE
SUPPORT FROM THE ECMWF ALBEIT WITH LESS QPF. PAST EXPERIENCE SHOWS
FOLLOWING THE HIGHER GFS QPF AMOUNTS IS STILL NOT ENOUGH AND THAT
REALITY BRINGS SIGNIFICANTLY MORE RAIN. ASSUMING THE CURRENT MODEL
RUNS STAY UNCHANGED IN THE FUTURE...WOULD EXPECT MULTIPLE MAINSTEM
RIVERS EXCEEDING FLOOD STAGE AS SOON AS SUNDAY MORNING.

WILL BEGIN TO ISSUE SOME OUTLOOK PRODUCTS TODAY WITH THE CAVEAT THAT
MODELS HAVE RELATIVELY RECENTLY SHIFTED THE FOCUS FROM NORTHERN
WASHINGTON/BRITISH COLUMBIA SOUTH TO OUR AREA. ADDITIONAL SHIFTING
IS EXPECTED AS WELL AS TIMING DIFFERENCES. STAY TUNED AS THIS
SITUATION EVOLVES OVER TIME. /JBONK

&&

.PREV DISC... /ISSUED 259 AM PST WED DEC 17 2014/

SHORT TERM...TODAY THROUGH SATURDAY...VERY LIGHT RAIN CONTINUES TO
IMPACT SW WASHINGTON THIS MORNING BUT HAS OTHERWISE STARTED TO
DISSIPATE OVER THE SOUTHERN PORTION OF THE FORECAST AREA. WATER
VAPOR IMAGERY SHOWS A CLOSED LOW WEAKENING AS IT HAS PUSHED ONSHORE
NEAR THE OREGON/CALIFORNIA BORDER...WHILE AN UPPER LEVEL SHORTWAVE
IS ELONGATING AS IT APPROACHES THE PACIFIC NORTHWEST COASTLINE. NOT
MUCH CHANGE IN THE KTTD-KDLS GRADIENT...WHICH REMAINS AROUND -5
EARLY THIS MORNING. EAST WINDS CONTINUE TO GUST NEAR 25 MPH THROUGH
THE GORGE...BUT EXPECT THE EASTERLY GRADIENT TO WEAKEN BY LATE
TONIGHT.

AFTER A PERIOD OF LIGHT RAIN THIS MORNING...MODELS REMAIN CONSISTENT
IN SHOWING AN UPTICK IN PRECIP BY THIS AFTERNOON ASSOCIATED WITH THE
VORT MAX JUST OFFSHORE AROUND 45N 134W. THE LOWER LEVEL MOISTURE
ASSOCIATED WITH THE SURFACE LOW COMBINED WITH THE UPPER LEVEL FORCING
FROM THE SHORTWAVE SHOULD DRIVE A PERIOD OF STEADIER PRECIP THIS
EVENING AND THROUGH TONIGHT. THE VORT MAX PUSHES EAST OF THE CASCADES
BY 12Z THU...AFTER WHICH SHOWER ACTIVITY SHOULD DROP OFF
SIGNIFICANTLY.

WITH CLEARING SKIES AND LIGHT WINDS...SHOULD SEE SOME SHALLOW FOG TO
DEVELOP IN INTERIOR VALLEYS TONIGHT THROUGH EARLY THU MORNING. MODELS
MAINTAIN A THREAT FOR LIGHT PRECIP OVER THE HIGHER TERRAIN MUCH OF
THU...BUT OTHERWISE EXPECT DRY CONDITIONS TO PERSIST TO LOWER
ELEVATIONS. THE NEXT SIGNIFICANT FRONTAL SYSTEM ARRIVES LATE
THU...SPREADING RAIN AND BRINGING GUSTY COASTAL WINDS TO THE REGION
THROUGH FRI. PRECIPITABLE WATER IS EXPECTED TO BE NEAR AN INCH AND AN
APPROACHING JET STREAK SHOULD PROVIDE GOOD LIFT AND EXPECT THE
HIGHEST RAINFALL TOTALS OF 0.75 TO 1 INCH ACROSS THE COAST AND COAST
RANGE THROUGH MIDDAY FRI. OTHER LOCATIONS WILL SEE ON AVERAGE 0.5
INCHES OF RAIN. SNOW LEVELS SHOULD REMAIN ABOVE 5000 FEET DURING THE
PEAK RAIN PERIOD...BUT LOWER TO NEAR OR BELOW THE CASCADE PASSES
BEHIND THE FRONT FRIDAY AFTERNOON.

STRONG LOW PRESSURE OVER THE GULF OF ALASKA WILL PUSH INLAND LATE FRI
INTO EARLY SAT MORNING...SIMULTANEOUSLY FLATTENING A BROAD AREA OF
HIGH PRESSURE OVER THE EASTERN PACIFIC. THERE IS INCREASING
CONFIDENCE AN ATMOSPHERIC RIVER SCENARIO WILL SET UP...WITH ABUNDANT
MOISTURE AIMED DIRECTLY AT THE PACIFIC NORTHWEST SAT.

LONG TERM...SATURDAY NIGHT THROUGH TUESDAY...AS THIS TROUGH MOVES ON
SHORE SATURDAY...THE ASSOCIATED COLD FRONT MOVES ONSHORE AND STALLS
EAST-TO-WEST ACROSS NORTHWEST OREGON AND SOUTHWEST WASHINGTON. THIS
PUTS OUR AREA IN THE PATH OF RAIN STARTING SATURDAY THROUGH MONDAY.
SOME UNCERTAINTY EXISTS IN WHERE THIS BOUNDARY WILL SET UP...WHICH
WILL DETERMINE HOW MUCH RAINFALL WE WILL GET. ON TUESDAY...GEFS
ENSEMBLE SPAGHETTI PLOTS GET MESSY AND SIGNIFICANT DIFFERENCES START
TO SHOW UP BETWEEN THE GFS AND ECMWF...DECREASING CONFIDENCE ON HOW
THE REST OF THE WEEK WILL SHAPE UP.  AS OF NOW...THE MOST COMMON
SOLUTION IS THAT HIGH PRESSURE RIDGING WILL START TO BUILD BACK OVER
THE WESTERN U.S. WHICH SUGGESTS DRIER WEATHER STARTING TUESDAY...
THOUGH UNCERTAINTY IS VERY HIGH. -MCCOY

&&

.AVIATION...VFR CONDITIONS TO PERSIST AT MOST TAF SITES THROUGH
THIS AFTERNOON. AS SHOWERS MOVE IN...THERE MAY BE PERIODS OF
MVFR...ESPECIALLY AT SOUTH WILLAMETTE VALLEY SITES. CLEARING IS
POSSIBLE THIS EVENING...ALLOWING FOG TO DEVELOP IFR CIGS AND
VIS...BUT UNCERTAINTY IS HIGH BECAUSE THE MODELS ARE HINTING AT A
WEAK LOW PRESSURE SYSTEM OFF THE SOUTH OREGON COAST MOVING INLAND
THIS EVENING. THIS COULD BRING ADDITIONAL SHOWERS AND WINDS WHICH
WOULD KEEP CIGS VFR/MVFR. IF ANY CLEARING DOES OCCUR...EXPECT CIGS
AND VIS TO DROP TO IFR WITH THE DEVELOPMENT OF FOG/LOW STRATUS.

KPDX AND APPROACHES...VFR CONDITIONS TO PERSIST WEDNESDAY.
RAIN MAY BRING PERIODS OF MVFR CIGS AND VIS. CIGS COULD DROP TO
IFR TONIGHT WITH THE DEVELOPMENT OF FOG/LOW STRATUS AFTER 09Z
THURSDAY. -MCCOY

&&

.MARINE...WEST SWELL AROUND 10 FT BRINGING SEAS UP TO SMALL CRAFT
CRITERIA TODAY. SEAS DROP BELOW 10 FT LATER THIS EVENING. THE
SYSTEM OF INTEREST WILL BE TOMORROW WHICH WILL LIKELY BRING
SOUTHERLY GALES THROUGH EARLY FRIDAY. THERE IS STILL SOME
UNCERTAINTY ON TIMING...BUT MODELS ARE COMING INTO AGREEMENT THAT
WINDS WILL START TO INCREASE EARLY THURSDAY MORNING...REACHING
GALE FORCE BY EARLY AFTERNOON. SEAS BUILD INTO THE TEENS THURSDAY
AFTERNOON. SEAS DROP BACK DOWN TO 10 TO 12 FT ON FRIDAY AHEAD OF
THE NEXT SYSTEM WHICH WILL BRING SEAS UP EVEN HIGHER ON SATURDAY.

THERE IS STILL UNCERTAINTY ON THE TIMING OF THE SATURDAY SYSTEM...BUT
AS OF NOW MODELS ARE SUGGESTING THAT WINDS COULD AGAIN REACH GALE
FORCE EARLY SATURDAY...WHICH COULD BUILD SEAS INTO THE LOW 20S.
SEAS START TO FALL EARLY SUNDAY...DROPPING BACK INTO THE LOW
TEENS BY LATE SUNDAY OR EARLY MONDAY. AN ACTIVE WEATHER PATTERN
WILL CONTINUE THROUGH THIS WEEKEND...KEEPING SEAS ELEVATED
THROUGH EARLY NEXT WEEK WITH PERIODS OF GALES POSSIBLE. -MCCOY


&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...GALE WATCH FROM THURSDAY MORNING THROUGH THURSDAY EVENING FOR
     COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 9 PM PST THIS
     EVENING FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 4 PM PST THIS AFTERNOON.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.



000
FXUS66 KOTX 171736
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
936 AM PST WED DEC 17 2014

.SYNOPSIS...
A more active weather pattern will develop through the week with
periods of light snow in the mountains...and rain or snow in the
valleys. Lower elevations from Interstate 90 south will see mainly
rain...while areas in the Cascades and near the Canadian border
will remain mainly snow. A much stronger weather system over the
weekend will usher in warmer temperatures with sharply rising snow
levels...as well as the potential for windy conditions.

&&

.DISCUSSION...
Quick update to increase pops and snow amounts for Wenatchee and
Waterville Plateau area as radar likly missing the stronger
returns as snow falls from lower cloud deck in that area. The wave
is weak and moving northeast. /Pelatti

&&

.AVIATION...
18Z TAFS: Weak disturbances drifting northeast and over the
aviation over the next 24 hours keep the forecast somewhat
cluttered with mentions of both rain and snow at times which
produce IFR/LIFR ceilings and visibilities. Some fog will
occasionally impact locations as well. Precipitation still on the
light side with the higher amounts primarily near the East Slopes
of the North Cascades out to the Waterville Plateau and points to
the north/northeast. The KGEG area will be more MVFR most of the
time as the precipitation will be light and likely to be rain.
/Pelatti

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        39  32  37  32  39  31 /  20  40  30  20  80  20
Coeur d`Alene  39  33  38  33  39  32 /  10  50  60  20  80  30
Pullman        43  33  43  34  42  29 /  10  50  40  10  70  20
Lewiston       43  35  45  36  44  31 /  10  40  30  10  60  20
Colville       35  32  37  33  38  32 /  20  50  30  50  80  20
Sandpoint      37  32  37  31  36  32 /  20  60  60  30  80  30
Kellogg        37  32  38  31  36  31 /  10  70  70  20  80  40
Moses Lake     39  29  39  32  42  28 /  20  20  10  60  60  10
Wenatchee      38  31  37  32  40  30 / 100  30  10  70  50  10
Omak           34  27  34  30  37  27 /  40  40  10  70  80  10

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 171736
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
936 AM PST WED DEC 17 2014

.SYNOPSIS...
A more active weather pattern will develop through the week with
periods of light snow in the mountains...and rain or snow in the
valleys. Lower elevations from Interstate 90 south will see mainly
rain...while areas in the Cascades and near the Canadian border
will remain mainly snow. A much stronger weather system over the
weekend will usher in warmer temperatures with sharply rising snow
levels...as well as the potential for windy conditions.

&&

.DISCUSSION...
Quick update to increase pops and snow amounts for Wenatchee and
Waterville Plateau area as radar likly missing the stronger
returns as snow falls from lower cloud deck in that area. The wave
is weak and moving northeast. /Pelatti

&&

.AVIATION...
18Z TAFS: Weak disturbances drifting northeast and over the
aviation over the next 24 hours keep the forecast somewhat
cluttered with mentions of both rain and snow at times which
produce IFR/LIFR ceilings and visibilities. Some fog will
occasionally impact locations as well. Precipitation still on the
light side with the higher amounts primarily near the East Slopes
of the North Cascades out to the Waterville Plateau and points to
the north/northeast. The KGEG area will be more MVFR most of the
time as the precipitation will be light and likely to be rain.
/Pelatti

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        39  32  37  32  39  31 /  20  40  30  20  80  20
Coeur d`Alene  39  33  38  33  39  32 /  10  50  60  20  80  30
Pullman        43  33  43  34  42  29 /  10  50  40  10  70  20
Lewiston       43  35  45  36  44  31 /  10  40  30  10  60  20
Colville       35  32  37  33  38  32 /  20  50  30  50  80  20
Sandpoint      37  32  37  31  36  32 /  20  60  60  30  80  30
Kellogg        37  32  38  31  36  31 /  10  70  70  20  80  40
Moses Lake     39  29  39  32  42  28 /  20  20  10  60  60  10
Wenatchee      38  31  37  32  40  30 / 100  30  10  70  50  10
Omak           34  27  34  30  37  27 /  40  40  10  70  80  10

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 171736
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
936 AM PST WED DEC 17 2014

.SYNOPSIS...
A more active weather pattern will develop through the week with
periods of light snow in the mountains...and rain or snow in the
valleys. Lower elevations from Interstate 90 south will see mainly
rain...while areas in the Cascades and near the Canadian border
will remain mainly snow. A much stronger weather system over the
weekend will usher in warmer temperatures with sharply rising snow
levels...as well as the potential for windy conditions.

&&

.DISCUSSION...
Quick update to increase pops and snow amounts for Wenatchee and
Waterville Plateau area as radar likly missing the stronger
returns as snow falls from lower cloud deck in that area. The wave
is weak and moving northeast. /Pelatti

&&

.AVIATION...
18Z TAFS: Weak disturbances drifting northeast and over the
aviation over the next 24 hours keep the forecast somewhat
cluttered with mentions of both rain and snow at times which
produce IFR/LIFR ceilings and visibilities. Some fog will
occasionally impact locations as well. Precipitation still on the
light side with the higher amounts primarily near the East Slopes
of the North Cascades out to the Waterville Plateau and points to
the north/northeast. The KGEG area will be more MVFR most of the
time as the precipitation will be light and likely to be rain.
/Pelatti

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        39  32  37  32  39  31 /  20  40  30  20  80  20
Coeur d`Alene  39  33  38  33  39  32 /  10  50  60  20  80  30
Pullman        43  33  43  34  42  29 /  10  50  40  10  70  20
Lewiston       43  35  45  36  44  31 /  10  40  30  10  60  20
Colville       35  32  37  33  38  32 /  20  50  30  50  80  20
Sandpoint      37  32  37  31  36  32 /  20  60  60  30  80  30
Kellogg        37  32  38  31  36  31 /  10  70  70  20  80  40
Moses Lake     39  29  39  32  42  28 /  20  20  10  60  60  10
Wenatchee      38  31  37  32  40  30 / 100  30  10  70  50  10
Omak           34  27  34  30  37  27 /  40  40  10  70  80  10

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 171736
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
936 AM PST WED DEC 17 2014

.SYNOPSIS...
A more active weather pattern will develop through the week with
periods of light snow in the mountains...and rain or snow in the
valleys. Lower elevations from Interstate 90 south will see mainly
rain...while areas in the Cascades and near the Canadian border
will remain mainly snow. A much stronger weather system over the
weekend will usher in warmer temperatures with sharply rising snow
levels...as well as the potential for windy conditions.

&&

.DISCUSSION...
Quick update to increase pops and snow amounts for Wenatchee and
Waterville Plateau area as radar likly missing the stronger
returns as snow falls from lower cloud deck in that area. The wave
is weak and moving northeast. /Pelatti

&&

.AVIATION...
18Z TAFS: Weak disturbances drifting northeast and over the
aviation over the next 24 hours keep the forecast somewhat
cluttered with mentions of both rain and snow at times which
produce IFR/LIFR ceilings and visibilities. Some fog will
occasionally impact locations as well. Precipitation still on the
light side with the higher amounts primarily near the East Slopes
of the North Cascades out to the Waterville Plateau and points to
the north/northeast. The KGEG area will be more MVFR most of the
time as the precipitation will be light and likely to be rain.
/Pelatti

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        39  32  37  32  39  31 /  20  40  30  20  80  20
Coeur d`Alene  39  33  38  33  39  32 /  10  50  60  20  80  30
Pullman        43  33  43  34  42  29 /  10  50  40  10  70  20
Lewiston       43  35  45  36  44  31 /  10  40  30  10  60  20
Colville       35  32  37  33  38  32 /  20  50  30  50  80  20
Sandpoint      37  32  37  31  36  32 /  20  60  60  30  80  30
Kellogg        37  32  38  31  36  31 /  10  70  70  20  80  40
Moses Lake     39  29  39  32  42  28 /  20  20  10  60  60  10
Wenatchee      38  31  37  32  40  30 / 100  30  10  70  50  10
Omak           34  27  34  30  37  27 /  40  40  10  70  80  10

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KSEW 171713
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 AM PST WED DEC 17 2014

.SYNOPSIS...A WEAK PACIFIC WEATHER SYSTEM WILL BRING SOME AREAS OF
LIGHT RAIN TO WESTERN WASHINGTON THROUGH WEDNESDAY NIGHT. A STRONGER
PACIFIC FRONTAL SYSTEM IS EXPECTED TO MOVE ASHORE THURSDAY NIGHT
WITH MORE SIGNIFICANT RAIN. ANOTHER WET WEATHER SYSTEM IS FORECAST
FOR THIS WEEKEND WITH HEAVIER RAIN AMOUNTS ALONG THE COAST AND IN
THE MOUNTAINS.

&&

.SHORT TERM...MODELS ARE NOT HANDLING THE NRN STREAM PORTION OF THE
SPLIT TROUGH AFFECTING WRN WA ALL THAT WELL. THE ELONGATED 500 MB
TROUGH AXIS IS OFFSHORE JUST INSIDE 130 W AND THERE IS STILL SOME
SURFACE STRUCTURE LEFT ACCORDING THE HRRR WHICH MOST MODELS DO NOT
SHOW. THE HRRR FROM YESTERDAY AFTERNOON IS THE WINNER WHICH WAS
SHOWING SLY FLOW ENTRAINING SOME MOISTURE FROM THE SRN STREAM SYSTEM
INTO WRN WA EARLY THIS MORNING. RADAR NOW SHOWS LIGHT RAIN AROUND
MUCH OF WRN WA INCLUDING PUGET SOUND. SOME MODELS LIKE THE GFS40
WERE MOSTLY DRY AND STILL SHOW ONLY LIGHT QPF FIELDS W OF THE SOUND
AND ACROSS THE FAR N AND CASCADES. THE HRRR DOES DRY OUT THE
INTERIOR BY LATE MORNING BEFORE SPREADING SOME LIGHT RAIN BACK INTO
THE AREA EARLY THIS EVENING LIKE THE NAM12 SHOWS. THIS TIMING IS
QUESTIONABLE GIVEN THE BRIGHT CLOUDS ON IR IMAGERY APPROACHING THE
COAST COUPLED WITH THE LANGLEY HILL RADAR SHOWING MORE RAIN BANDS
ALONG THE COAST LIFTING NE. WILL MAINTAIN THE CURRENT LIKELY POPS
FOR TODAY AND TONIGHT.

THE 500 MB TROUGH AXIS FINALLY SHIFTS E OF THE AREA BY 12Z THURSDAY
MORNING. WITH LIGHT FLOW AND A SHORT WAVE RIDGE TRAVERSING THE
AREA...EXPECT LOW CLOUDS AND MAYBE SOME FOG AROUND THE AREA. THIS
WILL BREAK UP BY MIDDAY AS THE NEXT STRONGER FRONT APPROACHES
INCREASING THE FLOW OUT AHEAD OF IT. TIMING IS STILL TRICKY WITH THE
06Z GFS BRINGING RAIN AS FAR INLAND AS THE WRN PORTION OF PUGET
SOUND BY LATE THURSDAY AFTERNOON. THE NAM12/ECMWF ARE SIMILAR BUT
THE CANADIAN IS STILL RUNNING A FEW HOURS FASTER WITH RAIN
OVERSPREADING WRN WA EARLIER IN THE AFTERNOON. WILL LEAVE POPS
UNCHANGED FOR NOW BUT MAY CONSIDER REMOVING SOME OF THE INTERIOR
POPS FOR A DRY PERIOD THURSDAY MORNING. THIS WOULD PROBABLY RESULT
IN MORE FOG AROUND THE AREA.

THE WARM FRONT MOVES THROUGH QUICKLY WITH COLDER AIR ARRIVING WITH
THE MAIN FRONTAL BAND SLATED FOR THURSDAY NIGHT. THIS SYSTEM APPEARS
TO SPLIT LESS THAN PREVIOUS FRONTS AND THE SE GRADIENTS ARE TIGHT
OVER THE AREA SO EXPECT LOCALLY WINDY CONDITIONS NORTH OF PUGET
SOUND AND ALONG THE COAST. SNOW LEVELS WILL FALL FROM NEAR 5000 FEET
TO 3000 TO 3500 FEET BY LATER THURSDAY NIGHT AND FRIDAY MORNING.
THERE IS A 6 HOUR WINDOW OF STRONGER FLOW ALONG AND BEHIND THE FRONT
WHICH COULD SQUEEZE OUT SEVERAL INCHES OF SNOW EVEN DOWN TO SOME OF
THE PASSES. SKI RESORTS COULD POSSIBLY GET CLOSE TO 6 INCHES OF SNOW
WHICH IS BORDERLINE ADVISORY CRITERIA. MOUNT BAKER MAY GET THE
HIGHER AMOUNTS IN THIS PATTERN. PRECIPITATION WILL FALL AS JUST RAIN
IN THE LOWLANDS...CHANGING TO SHOWERS DURING THE AFTERNOON. ANY
BREAK IN PRECIPITATION WILL AGAIN BE SHORT LIVED AS A STRONG 180+ KT
JET ACROSS THE PACIFIC DRIVES WETTER STORMS TOWARD THE AREA BY
SATURDAY.  MERCER

.LONG TERM...NO UPDATES FROM PREVIOUS DISCUSSION...LOOKS LIKE A
SHORT BREAK IN THE WEATHER FRIDAY NIGHT BEFORE THE NEXT WETTER
SYSTEM ARRIVES OVER THE WEEKEND. THIS SYSTEM WAS CURRENTLY MOVING
ACROSS 150E THIS MORNING WITH A SUPPORTING 200 KT JET. THE PROGS ARE
STILL TRENDING A BIT DRIER WITH THIS SYSTEM GIVEN ITS MORE
PROGRESSIVE NATURE. EXPECT RAIN TO INCREASE ON SATURDAY WITH THE
WARM FRONT AND THE COLD FRONT MOVING ONSHORE SUNDAY NIGHT.

RIDGING ALOFT ALONG THE WEST COAST MEANS THE JET STREAM WILL BE AT
OUR LATITUDE WITH A WESTERLY COMPONENT INTO THE CASCADES AND
SHADOWING OFF THE OLYMPICS THIS WEEKEND. THE COAST AND MOUNTAINS
SHOULD GET THE BULK OF THE PRECIPITATION.

ANOTHER SHORT BREAK MONDAY BEFORE THE NEXT NOT AS WET SYSTEM ARRIVES
TUESDAY. THE PROGS CONTINUE TO SUGGEST A KONA LOW DEVELOPING BUT
THEY ARE INCONSISTENT IN ITS POSITION. THE FURTHER WEST USUALLY
RESULTS IN BUILDING AN UPPER RIDGE NEAR 150W OR 160W AND PRODUCING
NORTHERLY FLOW ALOFT INTO THE PACIFIC NW FOR A MUCH COOLER FLOW
PATTERN. FURTHER EAST WITH THE PATTERN AND THE PACIFIC NW GETS A
MILDER NORTHERLY FLOW ALOFT. STAY TUNED HERE. BUEHNER

&&

.HYDROLOGY...NO UPDATES FROM PREVIOUS DISCUSSION...RIVER FLOODING IS
NOT EXPECTED THROUGH SATURDAY. MOIST WESTERLY FLOW WILL DEVELOP
SATURDAY NIGHT AND CONTINUE THROUGH SUNDAY NIGHT...WITH HEAVY
MOUNTAIN RAIN AMOUNTS POSSIBLE. GUIDANCE IS NOW SHOWING A BIT
LIGHTER AMOUNTS GIVEN THE MORE PROGRESSIVE NATURE OF THIS SYSTEM.
PRIMARY CONCERN FOR ANY RIVER RISING ABOVE FLOOD STAGE IS THE
SKOKOMISH BUT ALSO NEED TO KEEP AN EYE ON OTHER CASCADE FLOOD PRONE
STREAMS. BUEHNER

&&

.AVIATION...A STRETCHED OUT AND WEAKENING UPPER LEVEL TROUGH ALONG
THE COAST IS MOVING ONSHORE THIS MORNING AND WILL BE FOLLOWED BY
ANOTHER ONE...CURRENTLY ALONG 132W...TONIGHT. AT THE SURFACE...HIGH
PRES E OF THE CASCADES COMBINED WITH LOWER PRES OVER THE COASTAL
WATERS IS GIVING LIGHT OFFSHORE FLOW. THE AIR MASS IS MOIST AND
STABLE WITH LIGHT S TO SW FLOW ALOFT.

PACIFIC NW RADARS SHOW BANDS OF LIGHT RAIN EXTENDING SW FROM WESTERN
WASHINGTON INTO THE OREGON COASTAL WATERS. THIS MOISTURE IS MOVING
NE AHEAD OF THE INCOMING WEAKENING TROUGHS OFFSHORE. MOST
TERMINALS IN THE INTERIOR ARE SEEING VFR CEILINGS AND VISIBILITIES
DESPITE THE LIGHT RAIN AS A RESULT OF THE OFFSHORE PRES GRADIENTS.
THE EXCEPTIONS ARE AT KCLM WHERE PRECIPITATION AND FLOW MOVING ONTO
THE NORTH SLOPES OF THE OLYMPICS IS PRODUCING A LOWER STRATUS DECK
AND AROUND KOLM WHERE PRECIPITATION IN THE MORE TRAPPED SOUTHWEST
INTERIOR IS PRODUCING LOW IFR STRATUS AND VIS 3-5SM BR.

THE OFFSHORE PRES GRADIENTS ARE EXPECTED TO SLOWLY RELAX THROUGH
TONIGHT AS THE STRETCHING AND DYING TROUGHS OFFSHORE MOVE INTO THE
AREA. THIS WILL RESULT IN GENERALLY DETERIORATING CEILINGS AND
POORER VISIBILITIES AS WE MOVE INTO THE TONIGHT AND THU MORNING
PERIODS. EXPECT AREAS OF IFR CONDITIONS 06Z-18Z THU AT MANY OF THE
TERMINALS IN WESTERN WASHINGTON. ALBRECHT

KSEA...EXPECT CIGS AROUND 040 THROUGH THIS EVENING WITH PERIODS OF
LIGHT RAIN. CEILINGS WILL FALL TO 008-012 AFTER 05Z THIS EVENING AND
CONTINUE UNTIL 18Z. EXPECT VIS TO GENERALLY REMAIN ABOVE 5SM IN OCNL
-RA. EAST WIND AROUND 5 KT BECOMING SE TONIGHT. ALBRECHT

&&

.MARINE...WEAK TROUGHS OF LOW PRES...ONE OVER THE COASTAL WATERS AND
ANOTHER OVER THE OFFSHORE WATERS...WILL STRETCH OUT AND DIE AS THEY
MOVE INTO THE WATERS THIS AFTERNOON THROUGH TONIGHT. EXPECT LIGHT
OFFSHORE FLOW. WITH SEAS OVER THE COASTAL WATERS REMAINING AROUND 10
FT...THE SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS WAS EXTENDED INTO
THE NEARSHORE COASTAL WATERS. SEAS WILL SUBSIDE LATE THIS AFTERNOON
AND TONIGHT.

A STRONG PACIFIC FRONT ASSOCIATED WITH A 960 MB LOW CENTERED NEAR
49N 159W WILL APPROACH THE OFFSHORE WATERS ON THU...THEN MOVE INLAND
THU NIGHT. A PERIOD OF GALE FORCE WINDS CAN BE EXPECTED OVER THE
COASTAL WATERS LATER THU AFTERNOON THRU THU NIGHT AHEAD OF AND WITH
THE FRONT. A GALE WATCH IS IN EFFECT FOR THE COASTAL WATERS FOR THU
AFTERNOON AND NIGHT. THESE WILL LIKELY BE UPGRADED TO WARNINGS THIS
AFTERNOON.

THE FETCH AREA TO THE SOUTH OF THE LOW NEAR 49N 159W IS MOVING WITH
THE WAVE FIELD IT IS PRODUCING. THE WAVEWATCH MODEL CONTINUES TO
FORECAST SEAS 40-45 FT AROUND 47N 150W BY LATE TONIGHT. THESE WAVES
ARE EXPECTED TO DECAY INTO AN ENERGETIC 20-22 FT AT 18-20 SEC SWELL
ON THE WASHINGTON COAST LATE FRI AFTERNOON AND FRI NIGHT. AS IT
TURNS OUT...TIDAL ANOMALIES ALONG THE COAST ARE JUST OVER 1 FT ABOVE
NORMAL AND HIGH TIDE OCCURS EARLY SAT MORNING. IF SWELL REMAINS HIGH
INTO SAT MORNING...SOME COASTAL FLOODING IS POSSIBLE ALONG PORTIONS
OF THE COASTAL WATERS. IT IS TOO EARLY TO TELL AT THIS POINT AND TOO
EARLY TO ISSUE ANY COASTAL FLOOD WATCHES...BUT INTERESTS ON THE
COAST ARE URGED TO KEEP UP WITH LATEST FORECASTS.

ANOTHER STRONG WARM FRONT WILL ARRIVE ON SAT AND WILL LIKELY RESULT
IN A PERIOD OF GALE FORCE WINDS OVER THE COASTAL WATERS...THE NORTH
INLAND WATERS...AND THE ENTRANCES TO THE STRAIT OF JUAN DE FUCA.
ALBRECHT

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY TODAY FOR HAZARDOUS SEAS COASTAL
      WATERS.
     SMALL CRAFT ADVISORY TODAY FOR ROUGH GRAYS HARBOR BAR.
     GALE WATCH MIDDAY THURSDAY THROUGH LATE THURSDAY NIGHT FOR
      THE COASTAL WATERS.

&&

$$

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML











000
FXUS66 KSEW 171713
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 AM PST WED DEC 17 2014

.SYNOPSIS...A WEAK PACIFIC WEATHER SYSTEM WILL BRING SOME AREAS OF
LIGHT RAIN TO WESTERN WASHINGTON THROUGH WEDNESDAY NIGHT. A STRONGER
PACIFIC FRONTAL SYSTEM IS EXPECTED TO MOVE ASHORE THURSDAY NIGHT
WITH MORE SIGNIFICANT RAIN. ANOTHER WET WEATHER SYSTEM IS FORECAST
FOR THIS WEEKEND WITH HEAVIER RAIN AMOUNTS ALONG THE COAST AND IN
THE MOUNTAINS.

&&

.SHORT TERM...MODELS ARE NOT HANDLING THE NRN STREAM PORTION OF THE
SPLIT TROUGH AFFECTING WRN WA ALL THAT WELL. THE ELONGATED 500 MB
TROUGH AXIS IS OFFSHORE JUST INSIDE 130 W AND THERE IS STILL SOME
SURFACE STRUCTURE LEFT ACCORDING THE HRRR WHICH MOST MODELS DO NOT
SHOW. THE HRRR FROM YESTERDAY AFTERNOON IS THE WINNER WHICH WAS
SHOWING SLY FLOW ENTRAINING SOME MOISTURE FROM THE SRN STREAM SYSTEM
INTO WRN WA EARLY THIS MORNING. RADAR NOW SHOWS LIGHT RAIN AROUND
MUCH OF WRN WA INCLUDING PUGET SOUND. SOME MODELS LIKE THE GFS40
WERE MOSTLY DRY AND STILL SHOW ONLY LIGHT QPF FIELDS W OF THE SOUND
AND ACROSS THE FAR N AND CASCADES. THE HRRR DOES DRY OUT THE
INTERIOR BY LATE MORNING BEFORE SPREADING SOME LIGHT RAIN BACK INTO
THE AREA EARLY THIS EVENING LIKE THE NAM12 SHOWS. THIS TIMING IS
QUESTIONABLE GIVEN THE BRIGHT CLOUDS ON IR IMAGERY APPROACHING THE
COAST COUPLED WITH THE LANGLEY HILL RADAR SHOWING MORE RAIN BANDS
ALONG THE COAST LIFTING NE. WILL MAINTAIN THE CURRENT LIKELY POPS
FOR TODAY AND TONIGHT.

THE 500 MB TROUGH AXIS FINALLY SHIFTS E OF THE AREA BY 12Z THURSDAY
MORNING. WITH LIGHT FLOW AND A SHORT WAVE RIDGE TRAVERSING THE
AREA...EXPECT LOW CLOUDS AND MAYBE SOME FOG AROUND THE AREA. THIS
WILL BREAK UP BY MIDDAY AS THE NEXT STRONGER FRONT APPROACHES
INCREASING THE FLOW OUT AHEAD OF IT. TIMING IS STILL TRICKY WITH THE
06Z GFS BRINGING RAIN AS FAR INLAND AS THE WRN PORTION OF PUGET
SOUND BY LATE THURSDAY AFTERNOON. THE NAM12/ECMWF ARE SIMILAR BUT
THE CANADIAN IS STILL RUNNING A FEW HOURS FASTER WITH RAIN
OVERSPREADING WRN WA EARLIER IN THE AFTERNOON. WILL LEAVE POPS
UNCHANGED FOR NOW BUT MAY CONSIDER REMOVING SOME OF THE INTERIOR
POPS FOR A DRY PERIOD THURSDAY MORNING. THIS WOULD PROBABLY RESULT
IN MORE FOG AROUND THE AREA.

THE WARM FRONT MOVES THROUGH QUICKLY WITH COLDER AIR ARRIVING WITH
THE MAIN FRONTAL BAND SLATED FOR THURSDAY NIGHT. THIS SYSTEM APPEARS
TO SPLIT LESS THAN PREVIOUS FRONTS AND THE SE GRADIENTS ARE TIGHT
OVER THE AREA SO EXPECT LOCALLY WINDY CONDITIONS NORTH OF PUGET
SOUND AND ALONG THE COAST. SNOW LEVELS WILL FALL FROM NEAR 5000 FEET
TO 3000 TO 3500 FEET BY LATER THURSDAY NIGHT AND FRIDAY MORNING.
THERE IS A 6 HOUR WINDOW OF STRONGER FLOW ALONG AND BEHIND THE FRONT
WHICH COULD SQUEEZE OUT SEVERAL INCHES OF SNOW EVEN DOWN TO SOME OF
THE PASSES. SKI RESORTS COULD POSSIBLY GET CLOSE TO 6 INCHES OF SNOW
WHICH IS BORDERLINE ADVISORY CRITERIA. MOUNT BAKER MAY GET THE
HIGHER AMOUNTS IN THIS PATTERN. PRECIPITATION WILL FALL AS JUST RAIN
IN THE LOWLANDS...CHANGING TO SHOWERS DURING THE AFTERNOON. ANY
BREAK IN PRECIPITATION WILL AGAIN BE SHORT LIVED AS A STRONG 180+ KT
JET ACROSS THE PACIFIC DRIVES WETTER STORMS TOWARD THE AREA BY
SATURDAY.  MERCER

.LONG TERM...NO UPDATES FROM PREVIOUS DISCUSSION...LOOKS LIKE A
SHORT BREAK IN THE WEATHER FRIDAY NIGHT BEFORE THE NEXT WETTER
SYSTEM ARRIVES OVER THE WEEKEND. THIS SYSTEM WAS CURRENTLY MOVING
ACROSS 150E THIS MORNING WITH A SUPPORTING 200 KT JET. THE PROGS ARE
STILL TRENDING A BIT DRIER WITH THIS SYSTEM GIVEN ITS MORE
PROGRESSIVE NATURE. EXPECT RAIN TO INCREASE ON SATURDAY WITH THE
WARM FRONT AND THE COLD FRONT MOVING ONSHORE SUNDAY NIGHT.

RIDGING ALOFT ALONG THE WEST COAST MEANS THE JET STREAM WILL BE AT
OUR LATITUDE WITH A WESTERLY COMPONENT INTO THE CASCADES AND
SHADOWING OFF THE OLYMPICS THIS WEEKEND. THE COAST AND MOUNTAINS
SHOULD GET THE BULK OF THE PRECIPITATION.

ANOTHER SHORT BREAK MONDAY BEFORE THE NEXT NOT AS WET SYSTEM ARRIVES
TUESDAY. THE PROGS CONTINUE TO SUGGEST A KONA LOW DEVELOPING BUT
THEY ARE INCONSISTENT IN ITS POSITION. THE FURTHER WEST USUALLY
RESULTS IN BUILDING AN UPPER RIDGE NEAR 150W OR 160W AND PRODUCING
NORTHERLY FLOW ALOFT INTO THE PACIFIC NW FOR A MUCH COOLER FLOW
PATTERN. FURTHER EAST WITH THE PATTERN AND THE PACIFIC NW GETS A
MILDER NORTHERLY FLOW ALOFT. STAY TUNED HERE. BUEHNER

&&

.HYDROLOGY...NO UPDATES FROM PREVIOUS DISCUSSION...RIVER FLOODING IS
NOT EXPECTED THROUGH SATURDAY. MOIST WESTERLY FLOW WILL DEVELOP
SATURDAY NIGHT AND CONTINUE THROUGH SUNDAY NIGHT...WITH HEAVY
MOUNTAIN RAIN AMOUNTS POSSIBLE. GUIDANCE IS NOW SHOWING A BIT
LIGHTER AMOUNTS GIVEN THE MORE PROGRESSIVE NATURE OF THIS SYSTEM.
PRIMARY CONCERN FOR ANY RIVER RISING ABOVE FLOOD STAGE IS THE
SKOKOMISH BUT ALSO NEED TO KEEP AN EYE ON OTHER CASCADE FLOOD PRONE
STREAMS. BUEHNER

&&

.AVIATION...A STRETCHED OUT AND WEAKENING UPPER LEVEL TROUGH ALONG
THE COAST IS MOVING ONSHORE THIS MORNING AND WILL BE FOLLOWED BY
ANOTHER ONE...CURRENTLY ALONG 132W...TONIGHT. AT THE SURFACE...HIGH
PRES E OF THE CASCADES COMBINED WITH LOWER PRES OVER THE COASTAL
WATERS IS GIVING LIGHT OFFSHORE FLOW. THE AIR MASS IS MOIST AND
STABLE WITH LIGHT S TO SW FLOW ALOFT.

PACIFIC NW RADARS SHOW BANDS OF LIGHT RAIN EXTENDING SW FROM WESTERN
WASHINGTON INTO THE OREGON COASTAL WATERS. THIS MOISTURE IS MOVING
NE AHEAD OF THE INCOMING WEAKENING TROUGHS OFFSHORE. MOST
TERMINALS IN THE INTERIOR ARE SEEING VFR CEILINGS AND VISIBILITIES
DESPITE THE LIGHT RAIN AS A RESULT OF THE OFFSHORE PRES GRADIENTS.
THE EXCEPTIONS ARE AT KCLM WHERE PRECIPITATION AND FLOW MOVING ONTO
THE NORTH SLOPES OF THE OLYMPICS IS PRODUCING A LOWER STRATUS DECK
AND AROUND KOLM WHERE PRECIPITATION IN THE MORE TRAPPED SOUTHWEST
INTERIOR IS PRODUCING LOW IFR STRATUS AND VIS 3-5SM BR.

THE OFFSHORE PRES GRADIENTS ARE EXPECTED TO SLOWLY RELAX THROUGH
TONIGHT AS THE STRETCHING AND DYING TROUGHS OFFSHORE MOVE INTO THE
AREA. THIS WILL RESULT IN GENERALLY DETERIORATING CEILINGS AND
POORER VISIBILITIES AS WE MOVE INTO THE TONIGHT AND THU MORNING
PERIODS. EXPECT AREAS OF IFR CONDITIONS 06Z-18Z THU AT MANY OF THE
TERMINALS IN WESTERN WASHINGTON. ALBRECHT

KSEA...EXPECT CIGS AROUND 040 THROUGH THIS EVENING WITH PERIODS OF
LIGHT RAIN. CEILINGS WILL FALL TO 008-012 AFTER 05Z THIS EVENING AND
CONTINUE UNTIL 18Z. EXPECT VIS TO GENERALLY REMAIN ABOVE 5SM IN OCNL
-RA. EAST WIND AROUND 5 KT BECOMING SE TONIGHT. ALBRECHT

&&

.MARINE...WEAK TROUGHS OF LOW PRES...ONE OVER THE COASTAL WATERS AND
ANOTHER OVER THE OFFSHORE WATERS...WILL STRETCH OUT AND DIE AS THEY
MOVE INTO THE WATERS THIS AFTERNOON THROUGH TONIGHT. EXPECT LIGHT
OFFSHORE FLOW. WITH SEAS OVER THE COASTAL WATERS REMAINING AROUND 10
FT...THE SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS WAS EXTENDED INTO
THE NEARSHORE COASTAL WATERS. SEAS WILL SUBSIDE LATE THIS AFTERNOON
AND TONIGHT.

A STRONG PACIFIC FRONT ASSOCIATED WITH A 960 MB LOW CENTERED NEAR
49N 159W WILL APPROACH THE OFFSHORE WATERS ON THU...THEN MOVE INLAND
THU NIGHT. A PERIOD OF GALE FORCE WINDS CAN BE EXPECTED OVER THE
COASTAL WATERS LATER THU AFTERNOON THRU THU NIGHT AHEAD OF AND WITH
THE FRONT. A GALE WATCH IS IN EFFECT FOR THE COASTAL WATERS FOR THU
AFTERNOON AND NIGHT. THESE WILL LIKELY BE UPGRADED TO WARNINGS THIS
AFTERNOON.

THE FETCH AREA TO THE SOUTH OF THE LOW NEAR 49N 159W IS MOVING WITH
THE WAVE FIELD IT IS PRODUCING. THE WAVEWATCH MODEL CONTINUES TO
FORECAST SEAS 40-45 FT AROUND 47N 150W BY LATE TONIGHT. THESE WAVES
ARE EXPECTED TO DECAY INTO AN ENERGETIC 20-22 FT AT 18-20 SEC SWELL
ON THE WASHINGTON COAST LATE FRI AFTERNOON AND FRI NIGHT. AS IT
TURNS OUT...TIDAL ANOMALIES ALONG THE COAST ARE JUST OVER 1 FT ABOVE
NORMAL AND HIGH TIDE OCCURS EARLY SAT MORNING. IF SWELL REMAINS HIGH
INTO SAT MORNING...SOME COASTAL FLOODING IS POSSIBLE ALONG PORTIONS
OF THE COASTAL WATERS. IT IS TOO EARLY TO TELL AT THIS POINT AND TOO
EARLY TO ISSUE ANY COASTAL FLOOD WATCHES...BUT INTERESTS ON THE
COAST ARE URGED TO KEEP UP WITH LATEST FORECASTS.

ANOTHER STRONG WARM FRONT WILL ARRIVE ON SAT AND WILL LIKELY RESULT
IN A PERIOD OF GALE FORCE WINDS OVER THE COASTAL WATERS...THE NORTH
INLAND WATERS...AND THE ENTRANCES TO THE STRAIT OF JUAN DE FUCA.
ALBRECHT

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY TODAY FOR HAZARDOUS SEAS COASTAL
      WATERS.
     SMALL CRAFT ADVISORY TODAY FOR ROUGH GRAYS HARBOR BAR.
     GALE WATCH MIDDAY THURSDAY THROUGH LATE THURSDAY NIGHT FOR
      THE COASTAL WATERS.

&&

$$

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML











000
FXUS66 KSEW 171713
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 AM PST WED DEC 17 2014

.SYNOPSIS...A WEAK PACIFIC WEATHER SYSTEM WILL BRING SOME AREAS OF
LIGHT RAIN TO WESTERN WASHINGTON THROUGH WEDNESDAY NIGHT. A STRONGER
PACIFIC FRONTAL SYSTEM IS EXPECTED TO MOVE ASHORE THURSDAY NIGHT
WITH MORE SIGNIFICANT RAIN. ANOTHER WET WEATHER SYSTEM IS FORECAST
FOR THIS WEEKEND WITH HEAVIER RAIN AMOUNTS ALONG THE COAST AND IN
THE MOUNTAINS.

&&

.SHORT TERM...MODELS ARE NOT HANDLING THE NRN STREAM PORTION OF THE
SPLIT TROUGH AFFECTING WRN WA ALL THAT WELL. THE ELONGATED 500 MB
TROUGH AXIS IS OFFSHORE JUST INSIDE 130 W AND THERE IS STILL SOME
SURFACE STRUCTURE LEFT ACCORDING THE HRRR WHICH MOST MODELS DO NOT
SHOW. THE HRRR FROM YESTERDAY AFTERNOON IS THE WINNER WHICH WAS
SHOWING SLY FLOW ENTRAINING SOME MOISTURE FROM THE SRN STREAM SYSTEM
INTO WRN WA EARLY THIS MORNING. RADAR NOW SHOWS LIGHT RAIN AROUND
MUCH OF WRN WA INCLUDING PUGET SOUND. SOME MODELS LIKE THE GFS40
WERE MOSTLY DRY AND STILL SHOW ONLY LIGHT QPF FIELDS W OF THE SOUND
AND ACROSS THE FAR N AND CASCADES. THE HRRR DOES DRY OUT THE
INTERIOR BY LATE MORNING BEFORE SPREADING SOME LIGHT RAIN BACK INTO
THE AREA EARLY THIS EVENING LIKE THE NAM12 SHOWS. THIS TIMING IS
QUESTIONABLE GIVEN THE BRIGHT CLOUDS ON IR IMAGERY APPROACHING THE
COAST COUPLED WITH THE LANGLEY HILL RADAR SHOWING MORE RAIN BANDS
ALONG THE COAST LIFTING NE. WILL MAINTAIN THE CURRENT LIKELY POPS
FOR TODAY AND TONIGHT.

THE 500 MB TROUGH AXIS FINALLY SHIFTS E OF THE AREA BY 12Z THURSDAY
MORNING. WITH LIGHT FLOW AND A SHORT WAVE RIDGE TRAVERSING THE
AREA...EXPECT LOW CLOUDS AND MAYBE SOME FOG AROUND THE AREA. THIS
WILL BREAK UP BY MIDDAY AS THE NEXT STRONGER FRONT APPROACHES
INCREASING THE FLOW OUT AHEAD OF IT. TIMING IS STILL TRICKY WITH THE
06Z GFS BRINGING RAIN AS FAR INLAND AS THE WRN PORTION OF PUGET
SOUND BY LATE THURSDAY AFTERNOON. THE NAM12/ECMWF ARE SIMILAR BUT
THE CANADIAN IS STILL RUNNING A FEW HOURS FASTER WITH RAIN
OVERSPREADING WRN WA EARLIER IN THE AFTERNOON. WILL LEAVE POPS
UNCHANGED FOR NOW BUT MAY CONSIDER REMOVING SOME OF THE INTERIOR
POPS FOR A DRY PERIOD THURSDAY MORNING. THIS WOULD PROBABLY RESULT
IN MORE FOG AROUND THE AREA.

THE WARM FRONT MOVES THROUGH QUICKLY WITH COLDER AIR ARRIVING WITH
THE MAIN FRONTAL BAND SLATED FOR THURSDAY NIGHT. THIS SYSTEM APPEARS
TO SPLIT LESS THAN PREVIOUS FRONTS AND THE SE GRADIENTS ARE TIGHT
OVER THE AREA SO EXPECT LOCALLY WINDY CONDITIONS NORTH OF PUGET
SOUND AND ALONG THE COAST. SNOW LEVELS WILL FALL FROM NEAR 5000 FEET
TO 3000 TO 3500 FEET BY LATER THURSDAY NIGHT AND FRIDAY MORNING.
THERE IS A 6 HOUR WINDOW OF STRONGER FLOW ALONG AND BEHIND THE FRONT
WHICH COULD SQUEEZE OUT SEVERAL INCHES OF SNOW EVEN DOWN TO SOME OF
THE PASSES. SKI RESORTS COULD POSSIBLY GET CLOSE TO 6 INCHES OF SNOW
WHICH IS BORDERLINE ADVISORY CRITERIA. MOUNT BAKER MAY GET THE
HIGHER AMOUNTS IN THIS PATTERN. PRECIPITATION WILL FALL AS JUST RAIN
IN THE LOWLANDS...CHANGING TO SHOWERS DURING THE AFTERNOON. ANY
BREAK IN PRECIPITATION WILL AGAIN BE SHORT LIVED AS A STRONG 180+ KT
JET ACROSS THE PACIFIC DRIVES WETTER STORMS TOWARD THE AREA BY
SATURDAY.  MERCER

.LONG TERM...NO UPDATES FROM PREVIOUS DISCUSSION...LOOKS LIKE A
SHORT BREAK IN THE WEATHER FRIDAY NIGHT BEFORE THE NEXT WETTER
SYSTEM ARRIVES OVER THE WEEKEND. THIS SYSTEM WAS CURRENTLY MOVING
ACROSS 150E THIS MORNING WITH A SUPPORTING 200 KT JET. THE PROGS ARE
STILL TRENDING A BIT DRIER WITH THIS SYSTEM GIVEN ITS MORE
PROGRESSIVE NATURE. EXPECT RAIN TO INCREASE ON SATURDAY WITH THE
WARM FRONT AND THE COLD FRONT MOVING ONSHORE SUNDAY NIGHT.

RIDGING ALOFT ALONG THE WEST COAST MEANS THE JET STREAM WILL BE AT
OUR LATITUDE WITH A WESTERLY COMPONENT INTO THE CASCADES AND
SHADOWING OFF THE OLYMPICS THIS WEEKEND. THE COAST AND MOUNTAINS
SHOULD GET THE BULK OF THE PRECIPITATION.

ANOTHER SHORT BREAK MONDAY BEFORE THE NEXT NOT AS WET SYSTEM ARRIVES
TUESDAY. THE PROGS CONTINUE TO SUGGEST A KONA LOW DEVELOPING BUT
THEY ARE INCONSISTENT IN ITS POSITION. THE FURTHER WEST USUALLY
RESULTS IN BUILDING AN UPPER RIDGE NEAR 150W OR 160W AND PRODUCING
NORTHERLY FLOW ALOFT INTO THE PACIFIC NW FOR A MUCH COOLER FLOW
PATTERN. FURTHER EAST WITH THE PATTERN AND THE PACIFIC NW GETS A
MILDER NORTHERLY FLOW ALOFT. STAY TUNED HERE. BUEHNER

&&

.HYDROLOGY...NO UPDATES FROM PREVIOUS DISCUSSION...RIVER FLOODING IS
NOT EXPECTED THROUGH SATURDAY. MOIST WESTERLY FLOW WILL DEVELOP
SATURDAY NIGHT AND CONTINUE THROUGH SUNDAY NIGHT...WITH HEAVY
MOUNTAIN RAIN AMOUNTS POSSIBLE. GUIDANCE IS NOW SHOWING A BIT
LIGHTER AMOUNTS GIVEN THE MORE PROGRESSIVE NATURE OF THIS SYSTEM.
PRIMARY CONCERN FOR ANY RIVER RISING ABOVE FLOOD STAGE IS THE
SKOKOMISH BUT ALSO NEED TO KEEP AN EYE ON OTHER CASCADE FLOOD PRONE
STREAMS. BUEHNER

&&

.AVIATION...A STRETCHED OUT AND WEAKENING UPPER LEVEL TROUGH ALONG
THE COAST IS MOVING ONSHORE THIS MORNING AND WILL BE FOLLOWED BY
ANOTHER ONE...CURRENTLY ALONG 132W...TONIGHT. AT THE SURFACE...HIGH
PRES E OF THE CASCADES COMBINED WITH LOWER PRES OVER THE COASTAL
WATERS IS GIVING LIGHT OFFSHORE FLOW. THE AIR MASS IS MOIST AND
STABLE WITH LIGHT S TO SW FLOW ALOFT.

PACIFIC NW RADARS SHOW BANDS OF LIGHT RAIN EXTENDING SW FROM WESTERN
WASHINGTON INTO THE OREGON COASTAL WATERS. THIS MOISTURE IS MOVING
NE AHEAD OF THE INCOMING WEAKENING TROUGHS OFFSHORE. MOST
TERMINALS IN THE INTERIOR ARE SEEING VFR CEILINGS AND VISIBILITIES
DESPITE THE LIGHT RAIN AS A RESULT OF THE OFFSHORE PRES GRADIENTS.
THE EXCEPTIONS ARE AT KCLM WHERE PRECIPITATION AND FLOW MOVING ONTO
THE NORTH SLOPES OF THE OLYMPICS IS PRODUCING A LOWER STRATUS DECK
AND AROUND KOLM WHERE PRECIPITATION IN THE MORE TRAPPED SOUTHWEST
INTERIOR IS PRODUCING LOW IFR STRATUS AND VIS 3-5SM BR.

THE OFFSHORE PRES GRADIENTS ARE EXPECTED TO SLOWLY RELAX THROUGH
TONIGHT AS THE STRETCHING AND DYING TROUGHS OFFSHORE MOVE INTO THE
AREA. THIS WILL RESULT IN GENERALLY DETERIORATING CEILINGS AND
POORER VISIBILITIES AS WE MOVE INTO THE TONIGHT AND THU MORNING
PERIODS. EXPECT AREAS OF IFR CONDITIONS 06Z-18Z THU AT MANY OF THE
TERMINALS IN WESTERN WASHINGTON. ALBRECHT

KSEA...EXPECT CIGS AROUND 040 THROUGH THIS EVENING WITH PERIODS OF
LIGHT RAIN. CEILINGS WILL FALL TO 008-012 AFTER 05Z THIS EVENING AND
CONTINUE UNTIL 18Z. EXPECT VIS TO GENERALLY REMAIN ABOVE 5SM IN OCNL
-RA. EAST WIND AROUND 5 KT BECOMING SE TONIGHT. ALBRECHT

&&

.MARINE...WEAK TROUGHS OF LOW PRES...ONE OVER THE COASTAL WATERS AND
ANOTHER OVER THE OFFSHORE WATERS...WILL STRETCH OUT AND DIE AS THEY
MOVE INTO THE WATERS THIS AFTERNOON THROUGH TONIGHT. EXPECT LIGHT
OFFSHORE FLOW. WITH SEAS OVER THE COASTAL WATERS REMAINING AROUND 10
FT...THE SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS WAS EXTENDED INTO
THE NEARSHORE COASTAL WATERS. SEAS WILL SUBSIDE LATE THIS AFTERNOON
AND TONIGHT.

A STRONG PACIFIC FRONT ASSOCIATED WITH A 960 MB LOW CENTERED NEAR
49N 159W WILL APPROACH THE OFFSHORE WATERS ON THU...THEN MOVE INLAND
THU NIGHT. A PERIOD OF GALE FORCE WINDS CAN BE EXPECTED OVER THE
COASTAL WATERS LATER THU AFTERNOON THRU THU NIGHT AHEAD OF AND WITH
THE FRONT. A GALE WATCH IS IN EFFECT FOR THE COASTAL WATERS FOR THU
AFTERNOON AND NIGHT. THESE WILL LIKELY BE UPGRADED TO WARNINGS THIS
AFTERNOON.

THE FETCH AREA TO THE SOUTH OF THE LOW NEAR 49N 159W IS MOVING WITH
THE WAVE FIELD IT IS PRODUCING. THE WAVEWATCH MODEL CONTINUES TO
FORECAST SEAS 40-45 FT AROUND 47N 150W BY LATE TONIGHT. THESE WAVES
ARE EXPECTED TO DECAY INTO AN ENERGETIC 20-22 FT AT 18-20 SEC SWELL
ON THE WASHINGTON COAST LATE FRI AFTERNOON AND FRI NIGHT. AS IT
TURNS OUT...TIDAL ANOMALIES ALONG THE COAST ARE JUST OVER 1 FT ABOVE
NORMAL AND HIGH TIDE OCCURS EARLY SAT MORNING. IF SWELL REMAINS HIGH
INTO SAT MORNING...SOME COASTAL FLOODING IS POSSIBLE ALONG PORTIONS
OF THE COASTAL WATERS. IT IS TOO EARLY TO TELL AT THIS POINT AND TOO
EARLY TO ISSUE ANY COASTAL FLOOD WATCHES...BUT INTERESTS ON THE
COAST ARE URGED TO KEEP UP WITH LATEST FORECASTS.

ANOTHER STRONG WARM FRONT WILL ARRIVE ON SAT AND WILL LIKELY RESULT
IN A PERIOD OF GALE FORCE WINDS OVER THE COASTAL WATERS...THE NORTH
INLAND WATERS...AND THE ENTRANCES TO THE STRAIT OF JUAN DE FUCA.
ALBRECHT

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY TODAY FOR HAZARDOUS SEAS COASTAL
      WATERS.
     SMALL CRAFT ADVISORY TODAY FOR ROUGH GRAYS HARBOR BAR.
     GALE WATCH MIDDAY THURSDAY THROUGH LATE THURSDAY NIGHT FOR
      THE COASTAL WATERS.

&&

$$

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML











000
FXUS66 KSEW 171713
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 AM PST WED DEC 17 2014

.SYNOPSIS...A WEAK PACIFIC WEATHER SYSTEM WILL BRING SOME AREAS OF
LIGHT RAIN TO WESTERN WASHINGTON THROUGH WEDNESDAY NIGHT. A STRONGER
PACIFIC FRONTAL SYSTEM IS EXPECTED TO MOVE ASHORE THURSDAY NIGHT
WITH MORE SIGNIFICANT RAIN. ANOTHER WET WEATHER SYSTEM IS FORECAST
FOR THIS WEEKEND WITH HEAVIER RAIN AMOUNTS ALONG THE COAST AND IN
THE MOUNTAINS.

&&

.SHORT TERM...MODELS ARE NOT HANDLING THE NRN STREAM PORTION OF THE
SPLIT TROUGH AFFECTING WRN WA ALL THAT WELL. THE ELONGATED 500 MB
TROUGH AXIS IS OFFSHORE JUST INSIDE 130 W AND THERE IS STILL SOME
SURFACE STRUCTURE LEFT ACCORDING THE HRRR WHICH MOST MODELS DO NOT
SHOW. THE HRRR FROM YESTERDAY AFTERNOON IS THE WINNER WHICH WAS
SHOWING SLY FLOW ENTRAINING SOME MOISTURE FROM THE SRN STREAM SYSTEM
INTO WRN WA EARLY THIS MORNING. RADAR NOW SHOWS LIGHT RAIN AROUND
MUCH OF WRN WA INCLUDING PUGET SOUND. SOME MODELS LIKE THE GFS40
WERE MOSTLY DRY AND STILL SHOW ONLY LIGHT QPF FIELDS W OF THE SOUND
AND ACROSS THE FAR N AND CASCADES. THE HRRR DOES DRY OUT THE
INTERIOR BY LATE MORNING BEFORE SPREADING SOME LIGHT RAIN BACK INTO
THE AREA EARLY THIS EVENING LIKE THE NAM12 SHOWS. THIS TIMING IS
QUESTIONABLE GIVEN THE BRIGHT CLOUDS ON IR IMAGERY APPROACHING THE
COAST COUPLED WITH THE LANGLEY HILL RADAR SHOWING MORE RAIN BANDS
ALONG THE COAST LIFTING NE. WILL MAINTAIN THE CURRENT LIKELY POPS
FOR TODAY AND TONIGHT.

THE 500 MB TROUGH AXIS FINALLY SHIFTS E OF THE AREA BY 12Z THURSDAY
MORNING. WITH LIGHT FLOW AND A SHORT WAVE RIDGE TRAVERSING THE
AREA...EXPECT LOW CLOUDS AND MAYBE SOME FOG AROUND THE AREA. THIS
WILL BREAK UP BY MIDDAY AS THE NEXT STRONGER FRONT APPROACHES
INCREASING THE FLOW OUT AHEAD OF IT. TIMING IS STILL TRICKY WITH THE
06Z GFS BRINGING RAIN AS FAR INLAND AS THE WRN PORTION OF PUGET
SOUND BY LATE THURSDAY AFTERNOON. THE NAM12/ECMWF ARE SIMILAR BUT
THE CANADIAN IS STILL RUNNING A FEW HOURS FASTER WITH RAIN
OVERSPREADING WRN WA EARLIER IN THE AFTERNOON. WILL LEAVE POPS
UNCHANGED FOR NOW BUT MAY CONSIDER REMOVING SOME OF THE INTERIOR
POPS FOR A DRY PERIOD THURSDAY MORNING. THIS WOULD PROBABLY RESULT
IN MORE FOG AROUND THE AREA.

THE WARM FRONT MOVES THROUGH QUICKLY WITH COLDER AIR ARRIVING WITH
THE MAIN FRONTAL BAND SLATED FOR THURSDAY NIGHT. THIS SYSTEM APPEARS
TO SPLIT LESS THAN PREVIOUS FRONTS AND THE SE GRADIENTS ARE TIGHT
OVER THE AREA SO EXPECT LOCALLY WINDY CONDITIONS NORTH OF PUGET
SOUND AND ALONG THE COAST. SNOW LEVELS WILL FALL FROM NEAR 5000 FEET
TO 3000 TO 3500 FEET BY LATER THURSDAY NIGHT AND FRIDAY MORNING.
THERE IS A 6 HOUR WINDOW OF STRONGER FLOW ALONG AND BEHIND THE FRONT
WHICH COULD SQUEEZE OUT SEVERAL INCHES OF SNOW EVEN DOWN TO SOME OF
THE PASSES. SKI RESORTS COULD POSSIBLY GET CLOSE TO 6 INCHES OF SNOW
WHICH IS BORDERLINE ADVISORY CRITERIA. MOUNT BAKER MAY GET THE
HIGHER AMOUNTS IN THIS PATTERN. PRECIPITATION WILL FALL AS JUST RAIN
IN THE LOWLANDS...CHANGING TO SHOWERS DURING THE AFTERNOON. ANY
BREAK IN PRECIPITATION WILL AGAIN BE SHORT LIVED AS A STRONG 180+ KT
JET ACROSS THE PACIFIC DRIVES WETTER STORMS TOWARD THE AREA BY
SATURDAY.  MERCER

.LONG TERM...NO UPDATES FROM PREVIOUS DISCUSSION...LOOKS LIKE A
SHORT BREAK IN THE WEATHER FRIDAY NIGHT BEFORE THE NEXT WETTER
SYSTEM ARRIVES OVER THE WEEKEND. THIS SYSTEM WAS CURRENTLY MOVING
ACROSS 150E THIS MORNING WITH A SUPPORTING 200 KT JET. THE PROGS ARE
STILL TRENDING A BIT DRIER WITH THIS SYSTEM GIVEN ITS MORE
PROGRESSIVE NATURE. EXPECT RAIN TO INCREASE ON SATURDAY WITH THE
WARM FRONT AND THE COLD FRONT MOVING ONSHORE SUNDAY NIGHT.

RIDGING ALOFT ALONG THE WEST COAST MEANS THE JET STREAM WILL BE AT
OUR LATITUDE WITH A WESTERLY COMPONENT INTO THE CASCADES AND
SHADOWING OFF THE OLYMPICS THIS WEEKEND. THE COAST AND MOUNTAINS
SHOULD GET THE BULK OF THE PRECIPITATION.

ANOTHER SHORT BREAK MONDAY BEFORE THE NEXT NOT AS WET SYSTEM ARRIVES
TUESDAY. THE PROGS CONTINUE TO SUGGEST A KONA LOW DEVELOPING BUT
THEY ARE INCONSISTENT IN ITS POSITION. THE FURTHER WEST USUALLY
RESULTS IN BUILDING AN UPPER RIDGE NEAR 150W OR 160W AND PRODUCING
NORTHERLY FLOW ALOFT INTO THE PACIFIC NW FOR A MUCH COOLER FLOW
PATTERN. FURTHER EAST WITH THE PATTERN AND THE PACIFIC NW GETS A
MILDER NORTHERLY FLOW ALOFT. STAY TUNED HERE. BUEHNER

&&

.HYDROLOGY...NO UPDATES FROM PREVIOUS DISCUSSION...RIVER FLOODING IS
NOT EXPECTED THROUGH SATURDAY. MOIST WESTERLY FLOW WILL DEVELOP
SATURDAY NIGHT AND CONTINUE THROUGH SUNDAY NIGHT...WITH HEAVY
MOUNTAIN RAIN AMOUNTS POSSIBLE. GUIDANCE IS NOW SHOWING A BIT
LIGHTER AMOUNTS GIVEN THE MORE PROGRESSIVE NATURE OF THIS SYSTEM.
PRIMARY CONCERN FOR ANY RIVER RISING ABOVE FLOOD STAGE IS THE
SKOKOMISH BUT ALSO NEED TO KEEP AN EYE ON OTHER CASCADE FLOOD PRONE
STREAMS. BUEHNER

&&

.AVIATION...A STRETCHED OUT AND WEAKENING UPPER LEVEL TROUGH ALONG
THE COAST IS MOVING ONSHORE THIS MORNING AND WILL BE FOLLOWED BY
ANOTHER ONE...CURRENTLY ALONG 132W...TONIGHT. AT THE SURFACE...HIGH
PRES E OF THE CASCADES COMBINED WITH LOWER PRES OVER THE COASTAL
WATERS IS GIVING LIGHT OFFSHORE FLOW. THE AIR MASS IS MOIST AND
STABLE WITH LIGHT S TO SW FLOW ALOFT.

PACIFIC NW RADARS SHOW BANDS OF LIGHT RAIN EXTENDING SW FROM WESTERN
WASHINGTON INTO THE OREGON COASTAL WATERS. THIS MOISTURE IS MOVING
NE AHEAD OF THE INCOMING WEAKENING TROUGHS OFFSHORE. MOST
TERMINALS IN THE INTERIOR ARE SEEING VFR CEILINGS AND VISIBILITIES
DESPITE THE LIGHT RAIN AS A RESULT OF THE OFFSHORE PRES GRADIENTS.
THE EXCEPTIONS ARE AT KCLM WHERE PRECIPITATION AND FLOW MOVING ONTO
THE NORTH SLOPES OF THE OLYMPICS IS PRODUCING A LOWER STRATUS DECK
AND AROUND KOLM WHERE PRECIPITATION IN THE MORE TRAPPED SOUTHWEST
INTERIOR IS PRODUCING LOW IFR STRATUS AND VIS 3-5SM BR.

THE OFFSHORE PRES GRADIENTS ARE EXPECTED TO SLOWLY RELAX THROUGH
TONIGHT AS THE STRETCHING AND DYING TROUGHS OFFSHORE MOVE INTO THE
AREA. THIS WILL RESULT IN GENERALLY DETERIORATING CEILINGS AND
POORER VISIBILITIES AS WE MOVE INTO THE TONIGHT AND THU MORNING
PERIODS. EXPECT AREAS OF IFR CONDITIONS 06Z-18Z THU AT MANY OF THE
TERMINALS IN WESTERN WASHINGTON. ALBRECHT

KSEA...EXPECT CIGS AROUND 040 THROUGH THIS EVENING WITH PERIODS OF
LIGHT RAIN. CEILINGS WILL FALL TO 008-012 AFTER 05Z THIS EVENING AND
CONTINUE UNTIL 18Z. EXPECT VIS TO GENERALLY REMAIN ABOVE 5SM IN OCNL
-RA. EAST WIND AROUND 5 KT BECOMING SE TONIGHT. ALBRECHT

&&

.MARINE...WEAK TROUGHS OF LOW PRES...ONE OVER THE COASTAL WATERS AND
ANOTHER OVER THE OFFSHORE WATERS...WILL STRETCH OUT AND DIE AS THEY
MOVE INTO THE WATERS THIS AFTERNOON THROUGH TONIGHT. EXPECT LIGHT
OFFSHORE FLOW. WITH SEAS OVER THE COASTAL WATERS REMAINING AROUND 10
FT...THE SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS WAS EXTENDED INTO
THE NEARSHORE COASTAL WATERS. SEAS WILL SUBSIDE LATE THIS AFTERNOON
AND TONIGHT.

A STRONG PACIFIC FRONT ASSOCIATED WITH A 960 MB LOW CENTERED NEAR
49N 159W WILL APPROACH THE OFFSHORE WATERS ON THU...THEN MOVE INLAND
THU NIGHT. A PERIOD OF GALE FORCE WINDS CAN BE EXPECTED OVER THE
COASTAL WATERS LATER THU AFTERNOON THRU THU NIGHT AHEAD OF AND WITH
THE FRONT. A GALE WATCH IS IN EFFECT FOR THE COASTAL WATERS FOR THU
AFTERNOON AND NIGHT. THESE WILL LIKELY BE UPGRADED TO WARNINGS THIS
AFTERNOON.

THE FETCH AREA TO THE SOUTH OF THE LOW NEAR 49N 159W IS MOVING WITH
THE WAVE FIELD IT IS PRODUCING. THE WAVEWATCH MODEL CONTINUES TO
FORECAST SEAS 40-45 FT AROUND 47N 150W BY LATE TONIGHT. THESE WAVES
ARE EXPECTED TO DECAY INTO AN ENERGETIC 20-22 FT AT 18-20 SEC SWELL
ON THE WASHINGTON COAST LATE FRI AFTERNOON AND FRI NIGHT. AS IT
TURNS OUT...TIDAL ANOMALIES ALONG THE COAST ARE JUST OVER 1 FT ABOVE
NORMAL AND HIGH TIDE OCCURS EARLY SAT MORNING. IF SWELL REMAINS HIGH
INTO SAT MORNING...SOME COASTAL FLOODING IS POSSIBLE ALONG PORTIONS
OF THE COASTAL WATERS. IT IS TOO EARLY TO TELL AT THIS POINT AND TOO
EARLY TO ISSUE ANY COASTAL FLOOD WATCHES...BUT INTERESTS ON THE
COAST ARE URGED TO KEEP UP WITH LATEST FORECASTS.

ANOTHER STRONG WARM FRONT WILL ARRIVE ON SAT AND WILL LIKELY RESULT
IN A PERIOD OF GALE FORCE WINDS OVER THE COASTAL WATERS...THE NORTH
INLAND WATERS...AND THE ENTRANCES TO THE STRAIT OF JUAN DE FUCA.
ALBRECHT

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY TODAY FOR HAZARDOUS SEAS COASTAL
      WATERS.
     SMALL CRAFT ADVISORY TODAY FOR ROUGH GRAYS HARBOR BAR.
     GALE WATCH MIDDAY THURSDAY THROUGH LATE THURSDAY NIGHT FOR
      THE COASTAL WATERS.

&&

$$

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML











000
FXUS66 KOTX 171603
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
803 AM PST WED DEC 17 2014

.SYNOPSIS...
A more active weather pattern will develop through the week with
periods of light snow in the mountains...and rain or snow in the
valleys. Lower elevations from Interstate 90 south will see mainly
rain...while areas in the Cascades and near the Canadian border
will remain mainly snow. A much stronger weather system over the
weekend will usher in warmer temperatures with sharply rising snow
levels...as well as the potential for windy conditions.



&&

.DISCUSSION...
Quick update to increase pops and snow amounts for Wenatchee and
Waterville Plateau area as radar likly missing the stronger
returns as snow falls from lower cloud deck in that area. The wave
is weak and moving northeast. /Pelatti

&&

.AVIATION...
12Z TAFS: A few light flurries will be possible north of Spokane
through 15z...and snow will be on the increase near the crest of
the Cascades this morning as well. A northeast surface gradient
has scoured out the fog for all the TAF sites except for KEAT.
The stratus has also lifted into a mid level deck with VFR
conditions. KEAT is still in the fog and stratus with
MVFR cigs/vsby. The next weather disturbance will push across the
region later this morning. Light rain is expected at KEAT and
KMWH by mid morning. Behind the precipitation fog/stratus is once
again expected for KEAT/KMWH after 03z with MVFR/IFR cigs/vsby.
Precipitation...as mainly rain will hold for the eastern TAF
sites until late this afternoon and linger into the evening. MVFR
cigs/vsby expected with the rain. Tobin


&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        39  32  37  32  39  31 /  20  40  30  20  80  20
Coeur d`Alene  39  33  38  33  39  32 /  10  50  60  20  80  30
Pullman        43  33  43  34  42  29 /  10  50  40  10  70  20
Lewiston       43  35  45  36  44  31 /  10  40  30  10  60  20
Colville       35  32  37  33  38  32 /  20  50  30  50  80  20
Sandpoint      37  32  37  31  36  32 /  20  60  60  30  80  30
Kellogg        37  32  38  31  36  31 /  10  70  70  20  80  40
Moses Lake     39  29  39  32  42  28 /  20  20  10  60  60  10
Wenatchee      38  31  37  32  40  30 / 100  30  10  70  50  10
Omak           34  27  34  30  37  27 /  40  40  10  70  80  10

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$




000
FXUS66 KOTX 171603
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
803 AM PST WED DEC 17 2014

.SYNOPSIS...
A more active weather pattern will develop through the week with
periods of light snow in the mountains...and rain or snow in the
valleys. Lower elevations from Interstate 90 south will see mainly
rain...while areas in the Cascades and near the Canadian border
will remain mainly snow. A much stronger weather system over the
weekend will usher in warmer temperatures with sharply rising snow
levels...as well as the potential for windy conditions.



&&

.DISCUSSION...
Quick update to increase pops and snow amounts for Wenatchee and
Waterville Plateau area as radar likly missing the stronger
returns as snow falls from lower cloud deck in that area. The wave
is weak and moving northeast. /Pelatti

&&

.AVIATION...
12Z TAFS: A few light flurries will be possible north of Spokane
through 15z...and snow will be on the increase near the crest of
the Cascades this morning as well. A northeast surface gradient
has scoured out the fog for all the TAF sites except for KEAT.
The stratus has also lifted into a mid level deck with VFR
conditions. KEAT is still in the fog and stratus with
MVFR cigs/vsby. The next weather disturbance will push across the
region later this morning. Light rain is expected at KEAT and
KMWH by mid morning. Behind the precipitation fog/stratus is once
again expected for KEAT/KMWH after 03z with MVFR/IFR cigs/vsby.
Precipitation...as mainly rain will hold for the eastern TAF
sites until late this afternoon and linger into the evening. MVFR
cigs/vsby expected with the rain. Tobin


&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        39  32  37  32  39  31 /  20  40  30  20  80  20
Coeur d`Alene  39  33  38  33  39  32 /  10  50  60  20  80  30
Pullman        43  33  43  34  42  29 /  10  50  40  10  70  20
Lewiston       43  35  45  36  44  31 /  10  40  30  10  60  20
Colville       35  32  37  33  38  32 /  20  50  30  50  80  20
Sandpoint      37  32  37  31  36  32 /  20  60  60  30  80  30
Kellogg        37  32  38  31  36  31 /  10  70  70  20  80  40
Moses Lake     39  29  39  32  42  28 /  20  20  10  60  60  10
Wenatchee      38  31  37  32  40  30 / 100  30  10  70  50  10
Omak           34  27  34  30  37  27 /  40  40  10  70  80  10

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 171156
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
353 AM PST WED DEC 17 2014

.SYNOPSIS...
A more active weather pattern will develop through the week with
periods of light snow in the mountains...and rain or snow in the
valleys. Lower elevations from Interstate 90 south will see mainly
rain...while areas in the Cascades and near the Canadian border
will remain mainly snow. A much stronger weather system over the
weekend will usher in warmer temperatures with sharply rising snow
levels...as well as the potential for windy conditions.


&&

.DISCUSSION...
Today through Thursday night...The region will continue to be
under the influence of a split and ragged upper level trough
today and tonight. Again a couple of weak waves will move through
the forecast area and result in periods of light precipitation.
Cooler air banked up against the Cascades continues to make snow
level forecast a challenge. The 00z guidance came in with wet bulb
temperatures down around 30F when in fact the wet bulbs are in the
low to mid 30s. I most likely kept snow levels a little to low
across the areas for this morning, otherwise snow levels are
anywhere from 2500 to around 4000 feet across the area. So any
precipitation will be valley rain...possibly mixed with a little
snow for the Methow and up near Ardnevoir and mountain snow.
Precipitation amounts will remain light with a few hundredths in
the basin and lower valleys and possibly up to a tenth in the
mountains. Snow accumulations even for the mountains will only be
an inch or two.

Precipitation chances will then be on the decrease from the west
for the remainder of the night and Thursday as a short lived ridge
of high pressure builds into the region. Some pops were kept in
the orographically favored Panhandle mountains, but again
accumulations should remain light with light snow above 3500 feet
for the Panhandle. Fog and stratus will likely develop through
the night and Thursday morning with a saturated boundary layer and
light south-southwest winds.

The next system will move towards the region Thursday night and
increase Pacific moisture. Snow levels for the valleys near the
Cascades will again be problematic. I don`t see any freezing rain
at this time but precipitation probably as a snow or snow/rain mix
for those valleys and snow above 3000-3500 feet. Some of the
higher locations in the Cascades could see 3-5 inches of fresh
snow by early Friday morning. Tobin

Friday and Friday night...The next in a series of Pacific weather
systems pushes across the Inland Northwest on Friday with a warm
front followed closely by an occluded front Friday evening. This
one looks to be a little stronger and a little warmer.
Precipitation type will be tricky with light snow in the morning,
turning to valley rain and mountain snow by afternoon. There looks
to be the potential for up to an inch in the northern valleys,
while the northern mountains could see 1-3 inches. Drying occurs
behind the front Friday night with a brief break in the
precipitation and light winds.

Saturday through Sunday night...This still looks to be a wettest
period as an atmospheric river takes aim on the Pacific NW. The
GFS and ECMWF show agreement of moderate isentropic lift spreading
across the region Saturday morning with a stream of plentiful
moisture for most of the weekend. Again precipitation type will be
tricky, initially with valley snow possible in the valley northern
valleys especially in the Cascade valleys. Warming increases
Saturday night into Sunday, making it a mainly rain/high mountain
snow event by Sunday afternoon. The 850mb 0C line pushes to the
Canadian border on Sunday while temps of +5C to +7C poke into the
Columbia Basin. Sunday appears to be the warmest day with
widespread 40s and a few 50s possible. Moderate to heavy rainfall
is possible with juicy QPF amounts of 0.25" to 0.40" during a 24
hour period Saturday night into Sunday. Winds will increase by
Sunday evening with speeds 25-35 kts across the Columbia Basin.
Could even see some gusty mountain winds across the Cascades by
Sunday night. POPs and QPF amounts have been raised and winds
bumped for this period.

Monday through Tuesday...A cold front slides through the region
Monday allowing the atmospheric river to sag southward and cooler
drier air to filter in from the north. The bulk of the precipitation
will be found in the Cascades and Panhandle mountains through
Monday morning and then gradually taper off. Drier conditions and
clearing will allow temperatures to cool Monday night. This will
set the stage for the next weather system. Under the northwest
flow aloft, a disturbance is expected to drop down from the Gulf
of Alaska. A warm front will spread light precipitation across
eastern Washington by Tuesday. Based on low level temperatures,
there is good chance that the precipitation type will start off as
snow for most areas. /rfox.

&&

.AVIATION...
12Z TAFS: A few light flurries will be possible north of Spokane
through 15z...and snow will be on the increase near the crest of
the Cascades this morning as well. A northeast surface gradient
has scoured out the fog for all the TAF sites except for KEAT.
The stratus has also lifted into a mid level deck with VFR
conditions. KEAT is still in the fog and stratus with
MVFR cigs/vsby. The next weather disturbance will push across the
region later this morning. Light rain is expected at KEAT and
KMWH by mid morning. Behind the precipitation fog/stratus is once
again expected for KEAT/KMWH after 03z with MVFR/IFR cigs/vsby.
Precipitation...as mainly rain will hold for the eastern TAF
sites until late this afternoon and linger into the evening. MVFR
cigs/vsby expected with the rain. Tobin

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        39  32  37  32  39  31 /  20  40  30  20  80  20
Coeur d`Alene  39  33  38  33  39  32 /  10  50  60  20  80  30
Pullman        43  33  43  34  42  29 /  10  50  40  10  70  20
Lewiston       43  35  45  36  44  31 /  10  40  30  10  60  20
Colville       35  32  37  33  38  32 /  20  50  30  50  80  20
Sandpoint      37  32  37  31  36  32 /  20  60  60  30  80  30
Kellogg        37  32  38  31  36  31 /  10  70  70  20  80  40
Moses Lake     39  29  39  32  42  28 /  20  20  10  60  60  10
Wenatchee      38  31  37  32  40  30 /  50  30  10  70  50  10
Omak           34  27  34  30  37  27 /  40  40  10  70  80  10

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 171156
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
353 AM PST WED DEC 17 2014

.SYNOPSIS...
A more active weather pattern will develop through the week with
periods of light snow in the mountains...and rain or snow in the
valleys. Lower elevations from Interstate 90 south will see mainly
rain...while areas in the Cascades and near the Canadian border
will remain mainly snow. A much stronger weather system over the
weekend will usher in warmer temperatures with sharply rising snow
levels...as well as the potential for windy conditions.


&&

.DISCUSSION...
Today through Thursday night...The region will continue to be
under the influence of a split and ragged upper level trough
today and tonight. Again a couple of weak waves will move through
the forecast area and result in periods of light precipitation.
Cooler air banked up against the Cascades continues to make snow
level forecast a challenge. The 00z guidance came in with wet bulb
temperatures down around 30F when in fact the wet bulbs are in the
low to mid 30s. I most likely kept snow levels a little to low
across the areas for this morning, otherwise snow levels are
anywhere from 2500 to around 4000 feet across the area. So any
precipitation will be valley rain...possibly mixed with a little
snow for the Methow and up near Ardnevoir and mountain snow.
Precipitation amounts will remain light with a few hundredths in
the basin and lower valleys and possibly up to a tenth in the
mountains. Snow accumulations even for the mountains will only be
an inch or two.

Precipitation chances will then be on the decrease from the west
for the remainder of the night and Thursday as a short lived ridge
of high pressure builds into the region. Some pops were kept in
the orographically favored Panhandle mountains, but again
accumulations should remain light with light snow above 3500 feet
for the Panhandle. Fog and stratus will likely develop through
the night and Thursday morning with a saturated boundary layer and
light south-southwest winds.

The next system will move towards the region Thursday night and
increase Pacific moisture. Snow levels for the valleys near the
Cascades will again be problematic. I don`t see any freezing rain
at this time but precipitation probably as a snow or snow/rain mix
for those valleys and snow above 3000-3500 feet. Some of the
higher locations in the Cascades could see 3-5 inches of fresh
snow by early Friday morning. Tobin

Friday and Friday night...The next in a series of Pacific weather
systems pushes across the Inland Northwest on Friday with a warm
front followed closely by an occluded front Friday evening. This
one looks to be a little stronger and a little warmer.
Precipitation type will be tricky with light snow in the morning,
turning to valley rain and mountain snow by afternoon. There looks
to be the potential for up to an inch in the northern valleys,
while the northern mountains could see 1-3 inches. Drying occurs
behind the front Friday night with a brief break in the
precipitation and light winds.

Saturday through Sunday night...This still looks to be a wettest
period as an atmospheric river takes aim on the Pacific NW. The
GFS and ECMWF show agreement of moderate isentropic lift spreading
across the region Saturday morning with a stream of plentiful
moisture for most of the weekend. Again precipitation type will be
tricky, initially with valley snow possible in the valley northern
valleys especially in the Cascade valleys. Warming increases
Saturday night into Sunday, making it a mainly rain/high mountain
snow event by Sunday afternoon. The 850mb 0C line pushes to the
Canadian border on Sunday while temps of +5C to +7C poke into the
Columbia Basin. Sunday appears to be the warmest day with
widespread 40s and a few 50s possible. Moderate to heavy rainfall
is possible with juicy QPF amounts of 0.25" to 0.40" during a 24
hour period Saturday night into Sunday. Winds will increase by
Sunday evening with speeds 25-35 kts across the Columbia Basin.
Could even see some gusty mountain winds across the Cascades by
Sunday night. POPs and QPF amounts have been raised and winds
bumped for this period.

Monday through Tuesday...A cold front slides through the region
Monday allowing the atmospheric river to sag southward and cooler
drier air to filter in from the north. The bulk of the precipitation
will be found in the Cascades and Panhandle mountains through
Monday morning and then gradually taper off. Drier conditions and
clearing will allow temperatures to cool Monday night. This will
set the stage for the next weather system. Under the northwest
flow aloft, a disturbance is expected to drop down from the Gulf
of Alaska. A warm front will spread light precipitation across
eastern Washington by Tuesday. Based on low level temperatures,
there is good chance that the precipitation type will start off as
snow for most areas. /rfox.

&&

.AVIATION...
12Z TAFS: A few light flurries will be possible north of Spokane
through 15z...and snow will be on the increase near the crest of
the Cascades this morning as well. A northeast surface gradient
has scoured out the fog for all the TAF sites except for KEAT.
The stratus has also lifted into a mid level deck with VFR
conditions. KEAT is still in the fog and stratus with
MVFR cigs/vsby. The next weather disturbance will push across the
region later this morning. Light rain is expected at KEAT and
KMWH by mid morning. Behind the precipitation fog/stratus is once
again expected for KEAT/KMWH after 03z with MVFR/IFR cigs/vsby.
Precipitation...as mainly rain will hold for the eastern TAF
sites until late this afternoon and linger into the evening. MVFR
cigs/vsby expected with the rain. Tobin

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        39  32  37  32  39  31 /  20  40  30  20  80  20
Coeur d`Alene  39  33  38  33  39  32 /  10  50  60  20  80  30
Pullman        43  33  43  34  42  29 /  10  50  40  10  70  20
Lewiston       43  35  45  36  44  31 /  10  40  30  10  60  20
Colville       35  32  37  33  38  32 /  20  50  30  50  80  20
Sandpoint      37  32  37  31  36  32 /  20  60  60  30  80  30
Kellogg        37  32  38  31  36  31 /  10  70  70  20  80  40
Moses Lake     39  29  39  32  42  28 /  20  20  10  60  60  10
Wenatchee      38  31  37  32  40  30 /  50  30  10  70  50  10
Omak           34  27  34  30  37  27 /  40  40  10  70  80  10

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 171156
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
353 AM PST WED DEC 17 2014

.SYNOPSIS...
A more active weather pattern will develop through the week with
periods of light snow in the mountains...and rain or snow in the
valleys. Lower elevations from Interstate 90 south will see mainly
rain...while areas in the Cascades and near the Canadian border
will remain mainly snow. A much stronger weather system over the
weekend will usher in warmer temperatures with sharply rising snow
levels...as well as the potential for windy conditions.


&&

.DISCUSSION...
Today through Thursday night...The region will continue to be
under the influence of a split and ragged upper level trough
today and tonight. Again a couple of weak waves will move through
the forecast area and result in periods of light precipitation.
Cooler air banked up against the Cascades continues to make snow
level forecast a challenge. The 00z guidance came in with wet bulb
temperatures down around 30F when in fact the wet bulbs are in the
low to mid 30s. I most likely kept snow levels a little to low
across the areas for this morning, otherwise snow levels are
anywhere from 2500 to around 4000 feet across the area. So any
precipitation will be valley rain...possibly mixed with a little
snow for the Methow and up near Ardnevoir and mountain snow.
Precipitation amounts will remain light with a few hundredths in
the basin and lower valleys and possibly up to a tenth in the
mountains. Snow accumulations even for the mountains will only be
an inch or two.

Precipitation chances will then be on the decrease from the west
for the remainder of the night and Thursday as a short lived ridge
of high pressure builds into the region. Some pops were kept in
the orographically favored Panhandle mountains, but again
accumulations should remain light with light snow above 3500 feet
for the Panhandle. Fog and stratus will likely develop through
the night and Thursday morning with a saturated boundary layer and
light south-southwest winds.

The next system will move towards the region Thursday night and
increase Pacific moisture. Snow levels for the valleys near the
Cascades will again be problematic. I don`t see any freezing rain
at this time but precipitation probably as a snow or snow/rain mix
for those valleys and snow above 3000-3500 feet. Some of the
higher locations in the Cascades could see 3-5 inches of fresh
snow by early Friday morning. Tobin

Friday and Friday night...The next in a series of Pacific weather
systems pushes across the Inland Northwest on Friday with a warm
front followed closely by an occluded front Friday evening. This
one looks to be a little stronger and a little warmer.
Precipitation type will be tricky with light snow in the morning,
turning to valley rain and mountain snow by afternoon. There looks
to be the potential for up to an inch in the northern valleys,
while the northern mountains could see 1-3 inches. Drying occurs
behind the front Friday night with a brief break in the
precipitation and light winds.

Saturday through Sunday night...This still looks to be a wettest
period as an atmospheric river takes aim on the Pacific NW. The
GFS and ECMWF show agreement of moderate isentropic lift spreading
across the region Saturday morning with a stream of plentiful
moisture for most of the weekend. Again precipitation type will be
tricky, initially with valley snow possible in the valley northern
valleys especially in the Cascade valleys. Warming increases
Saturday night into Sunday, making it a mainly rain/high mountain
snow event by Sunday afternoon. The 850mb 0C line pushes to the
Canadian border on Sunday while temps of +5C to +7C poke into the
Columbia Basin. Sunday appears to be the warmest day with
widespread 40s and a few 50s possible. Moderate to heavy rainfall
is possible with juicy QPF amounts of 0.25" to 0.40" during a 24
hour period Saturday night into Sunday. Winds will increase by
Sunday evening with speeds 25-35 kts across the Columbia Basin.
Could even see some gusty mountain winds across the Cascades by
Sunday night. POPs and QPF amounts have been raised and winds
bumped for this period.

Monday through Tuesday...A cold front slides through the region
Monday allowing the atmospheric river to sag southward and cooler
drier air to filter in from the north. The bulk of the precipitation
will be found in the Cascades and Panhandle mountains through
Monday morning and then gradually taper off. Drier conditions and
clearing will allow temperatures to cool Monday night. This will
set the stage for the next weather system. Under the northwest
flow aloft, a disturbance is expected to drop down from the Gulf
of Alaska. A warm front will spread light precipitation across
eastern Washington by Tuesday. Based on low level temperatures,
there is good chance that the precipitation type will start off as
snow for most areas. /rfox.

&&

.AVIATION...
12Z TAFS: A few light flurries will be possible north of Spokane
through 15z...and snow will be on the increase near the crest of
the Cascades this morning as well. A northeast surface gradient
has scoured out the fog for all the TAF sites except for KEAT.
The stratus has also lifted into a mid level deck with VFR
conditions. KEAT is still in the fog and stratus with
MVFR cigs/vsby. The next weather disturbance will push across the
region later this morning. Light rain is expected at KEAT and
KMWH by mid morning. Behind the precipitation fog/stratus is once
again expected for KEAT/KMWH after 03z with MVFR/IFR cigs/vsby.
Precipitation...as mainly rain will hold for the eastern TAF
sites until late this afternoon and linger into the evening. MVFR
cigs/vsby expected with the rain. Tobin

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        39  32  37  32  39  31 /  20  40  30  20  80  20
Coeur d`Alene  39  33  38  33  39  32 /  10  50  60  20  80  30
Pullman        43  33  43  34  42  29 /  10  50  40  10  70  20
Lewiston       43  35  45  36  44  31 /  10  40  30  10  60  20
Colville       35  32  37  33  38  32 /  20  50  30  50  80  20
Sandpoint      37  32  37  31  36  32 /  20  60  60  30  80  30
Kellogg        37  32  38  31  36  31 /  10  70  70  20  80  40
Moses Lake     39  29  39  32  42  28 /  20  20  10  60  60  10
Wenatchee      38  31  37  32  40  30 /  50  30  10  70  50  10
Omak           34  27  34  30  37  27 /  40  40  10  70  80  10

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 171156
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
353 AM PST WED DEC 17 2014

.SYNOPSIS...
A more active weather pattern will develop through the week with
periods of light snow in the mountains...and rain or snow in the
valleys. Lower elevations from Interstate 90 south will see mainly
rain...while areas in the Cascades and near the Canadian border
will remain mainly snow. A much stronger weather system over the
weekend will usher in warmer temperatures with sharply rising snow
levels...as well as the potential for windy conditions.


&&

.DISCUSSION...
Today through Thursday night...The region will continue to be
under the influence of a split and ragged upper level trough
today and tonight. Again a couple of weak waves will move through
the forecast area and result in periods of light precipitation.
Cooler air banked up against the Cascades continues to make snow
level forecast a challenge. The 00z guidance came in with wet bulb
temperatures down around 30F when in fact the wet bulbs are in the
low to mid 30s. I most likely kept snow levels a little to low
across the areas for this morning, otherwise snow levels are
anywhere from 2500 to around 4000 feet across the area. So any
precipitation will be valley rain...possibly mixed with a little
snow for the Methow and up near Ardnevoir and mountain snow.
Precipitation amounts will remain light with a few hundredths in
the basin and lower valleys and possibly up to a tenth in the
mountains. Snow accumulations even for the mountains will only be
an inch or two.

Precipitation chances will then be on the decrease from the west
for the remainder of the night and Thursday as a short lived ridge
of high pressure builds into the region. Some pops were kept in
the orographically favored Panhandle mountains, but again
accumulations should remain light with light snow above 3500 feet
for the Panhandle. Fog and stratus will likely develop through
the night and Thursday morning with a saturated boundary layer and
light south-southwest winds.

The next system will move towards the region Thursday night and
increase Pacific moisture. Snow levels for the valleys near the
Cascades will again be problematic. I don`t see any freezing rain
at this time but precipitation probably as a snow or snow/rain mix
for those valleys and snow above 3000-3500 feet. Some of the
higher locations in the Cascades could see 3-5 inches of fresh
snow by early Friday morning. Tobin

Friday and Friday night...The next in a series of Pacific weather
systems pushes across the Inland Northwest on Friday with a warm
front followed closely by an occluded front Friday evening. This
one looks to be a little stronger and a little warmer.
Precipitation type will be tricky with light snow in the morning,
turning to valley rain and mountain snow by afternoon. There looks
to be the potential for up to an inch in the northern valleys,
while the northern mountains could see 1-3 inches. Drying occurs
behind the front Friday night with a brief break in the
precipitation and light winds.

Saturday through Sunday night...This still looks to be a wettest
period as an atmospheric river takes aim on the Pacific NW. The
GFS and ECMWF show agreement of moderate isentropic lift spreading
across the region Saturday morning with a stream of plentiful
moisture for most of the weekend. Again precipitation type will be
tricky, initially with valley snow possible in the valley northern
valleys especially in the Cascade valleys. Warming increases
Saturday night into Sunday, making it a mainly rain/high mountain
snow event by Sunday afternoon. The 850mb 0C line pushes to the
Canadian border on Sunday while temps of +5C to +7C poke into the
Columbia Basin. Sunday appears to be the warmest day with
widespread 40s and a few 50s possible. Moderate to heavy rainfall
is possible with juicy QPF amounts of 0.25" to 0.40" during a 24
hour period Saturday night into Sunday. Winds will increase by
Sunday evening with speeds 25-35 kts across the Columbia Basin.
Could even see some gusty mountain winds across the Cascades by
Sunday night. POPs and QPF amounts have been raised and winds
bumped for this period.

Monday through Tuesday...A cold front slides through the region
Monday allowing the atmospheric river to sag southward and cooler
drier air to filter in from the north. The bulk of the precipitation
will be found in the Cascades and Panhandle mountains through
Monday morning and then gradually taper off. Drier conditions and
clearing will allow temperatures to cool Monday night. This will
set the stage for the next weather system. Under the northwest
flow aloft, a disturbance is expected to drop down from the Gulf
of Alaska. A warm front will spread light precipitation across
eastern Washington by Tuesday. Based on low level temperatures,
there is good chance that the precipitation type will start off as
snow for most areas. /rfox.

&&

.AVIATION...
12Z TAFS: A few light flurries will be possible north of Spokane
through 15z...and snow will be on the increase near the crest of
the Cascades this morning as well. A northeast surface gradient
has scoured out the fog for all the TAF sites except for KEAT.
The stratus has also lifted into a mid level deck with VFR
conditions. KEAT is still in the fog and stratus with
MVFR cigs/vsby. The next weather disturbance will push across the
region later this morning. Light rain is expected at KEAT and
KMWH by mid morning. Behind the precipitation fog/stratus is once
again expected for KEAT/KMWH after 03z with MVFR/IFR cigs/vsby.
Precipitation...as mainly rain will hold for the eastern TAF
sites until late this afternoon and linger into the evening. MVFR
cigs/vsby expected with the rain. Tobin

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        39  32  37  32  39  31 /  20  40  30  20  80  20
Coeur d`Alene  39  33  38  33  39  32 /  10  50  60  20  80  30
Pullman        43  33  43  34  42  29 /  10  50  40  10  70  20
Lewiston       43  35  45  36  44  31 /  10  40  30  10  60  20
Colville       35  32  37  33  38  32 /  20  50  30  50  80  20
Sandpoint      37  32  37  31  36  32 /  20  60  60  30  80  30
Kellogg        37  32  38  31  36  31 /  10  70  70  20  80  40
Moses Lake     39  29  39  32  42  28 /  20  20  10  60  60  10
Wenatchee      38  31  37  32  40  30 /  50  30  10  70  50  10
Omak           34  27  34  30  37  27 /  40  40  10  70  80  10

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KSEW 171100
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 AM PST WED DEC 17 2014

.SYNOPSIS...A WEAK PACIFIC WEATHER SYSTEM WILL BRING SOME AREAS OF
LIGHT RAIN TO WESTERN WASHINGTON THROUGH WEDNESDAY NIGHT. A STRONGER
PACIFIC FRONTAL SYSTEM IS EXPECTED TO MOVE ASHORE THURSDAY NIGHT
WITH MORE SIGNIFICANT RAIN. ANOTHER WET WEATHER SYSTEM IS FORECAST
FOR THIS WEEKEND WITH HEAVIER RAIN AMOUNTS ALONG THE COAST AND IN
THE MOUNTAINS.

&&

.SHORT TERM...A NEGATIVE TILTED UPPER TROUGH WITH SPLIT FLOW IS JUST
OFF THE COAST EARLY THIS MORNING. THE PRIMARY FLOW ALOFT IS INTO
CALIFORNIA WHERE THE BULK OF THE PRECIP IS HEADED. A WEAKENING
SHORTWAVE WAS PRODUCING LIGHT RAIN ALONG THE COAST AND SOME OF THAT
SHOULD MOVE FURTHER INLAND LATER TODAY. RAIN AMOUNTS LIGHT THOUGH.

THE NEXT SHORTWAVE ON SATELITE IMAGERY WAS MOVING INSIDE 135W AGAIN
WITH THE BULK OF THE ENERGY HEADING TOWARD THE GOLDEN STATE. THE
REMAINING STRETCHED OUT PORTION AT OUR LATITUDE WILL LIKELY SPREAD
SOME ADDITIONAL LIGHT RAIN ONSHORE TONIGHT.

THE NEXT UPSTREAM AND STRONGER SHORTWAVE WAS NEAR 160W EARLY THIS
MORNING. THIS SYSTEM WAS PUMPING UP A SHORTWAVE RIDGE AHEAD OF IT
THAT PROGS AGREE WILL MOVE ONSHORE THURSDAY. THEN THE ASSOCIATED
FRONTAL SYSTEM SHOULD BEGIN TO SPREAD RAIN ONSHORE LATE THURSDAY
WITH THE COLD FRONT MOVING INLAND EARLY FRIDAY. BLUSTERY WINDS FOR
THE COAST AND NORTH INTERIOR WITH THIS SYSTEM. THE SHORTWAVE TROUGH
IS THEN FORECAST TO MOVE ASHORE FOR A BIT COOLER SHOWERY DAY FRIDAY.

FOR THE MOUNTAINS...THE LACK OF SNOW IS A CONCERN. THE WEATHER
SYSTEMS TODAY THROUGH FRIDAY SHOULD PRODUCE AT LEAST SOME SNOWFALL
THERE. EAST TO WEST GRADIENTS ACROSS THE CASCADES SHOULD TEND TO
KEEP THE SNOW LEVELS CLOSE TO THE PASSES UNTIL THE THURSDAY NIGHT
SYSTEM MOVES ONSHORE EARLY FRIDAY. BY THEN...THE FOLLOWING SHORTWAVE
TROUGH WILL BRING SOME COOLER UNSTABLE AIR FOR SNOW SHOWERS. NOT A
WHOLE LOT OF SNOW IN THE NEXT 3 DAYS...BUT BETTER THAN LAST WEEKS
MILD WET WEATHER. BUEHNER

.LONG TERM...LOOKS LIKE A SHORT BREAK IN THE WEATHER FRIDAY NIGHT
BEFORE THE NEXT WETTER SYSTEM ARRIVES OVER THE WEEKEND. THIS SYSTEM
WAS CURRENTLY MOVING ACROSS 150E THIS MORNING WITH A SUPPORTING 200
KT JET. THE PROGS ARE STILL TRENDING A BIT DRIER WITH THIS SYSTEM
GIVEN ITS MORE PROGRESSIVE NATURE. EXPECT RAIN TO INCREASE ON
SATURDAY WITH THE WARM FRONT AND THE COLD FRONT MOVING ONSHORE
SUNDAY NIGHT.

RIDGING ALOFT ALONG THE WEST COAST MEANS THE JET STREAM WILL BE AT
OUR LATITUDE WITH A WESTERLY COMPONENT INTO THE CASCADES AND
SHADOWING OFF THE OLYMPICS THIS WEEKEND. THE COAST AND MOUNTAINS
SHOULD GET THE BULK OF THE PRECIPITATION.

ANOTHER SHORT BREAK MONDAY BEFORE THE NEXT NOT AS WET SYSTEM ARRIVES
TUESDAY. THE PROGS CONTINUE TO SUGGEST A KONA LOW DEVELOPING BUT
THEY ARE INCONSISTENT IN ITS POSITION. THE FURTHER WEST USUALLY
RESULTS IN BUILDING AN UPPER RIDGE NEAR 150W OR 160W AND PRODUCING
NORTHERLY FLOW ALOFT INTO THE PACIFIC NW FOR A MUCH COOLER FLOW
PATTERN. FURTHER EAST WITH THE PATTERN AND THE PACIFIC NW GETS A
MILDER NORTHERLY FLOW ALOFT. STAY TUNED HERE. BUEHNER

&&

.HYDROLOGY...RIVER FLOODING IS NOT EXPECTED THROUGH SATURDAY. MOIST
WESTERLY FLOW WILL DEVELOP SATURDAY NIGHT AND CONTINUE THROUGH
SUNDAY NIGHT...WITH HEAVY MOUNTAIN RAIN AMOUNTS POSSIBLE.
GUIDANCE IS NOW SHOWING A BIT LIGHTER AMOUNTS GIVEN THE MORE
PROGRESSIVE NATURE OF THIS SYSTEM. PRIMARY CONCERN FOR ANY RIVER
RISING ABOVE FLOOD STAGE IS THE SKOKOMISH BUT ALSO NEED TO KEEP AN
EYE ON OTHER CASCADE FLOOD PRONE STREAMS. BUEHNER

&&

.AVIATION...AN UPPER LEVEL TROUGH WILL GIVE LIGHT SOUTHWEST FLOW
ALOFT OVER WESTERN WASHINGTON TODAY. LOW LEVEL OFFSHORE FLOW WILL
EASE AS A SURFACE TROUGH MOVES ONSHORE AND RIDGING EAST OF THE
CASCADES WEAKENS. THE AIR MASS WILL REMAIN MOIST AND STABLE WITH
AREAS OF VERY LIGHT PRECIPITATION MOVING THROUGH AT TIMES.

STRATUS OVER THE SOUTHWEST INTERIOR OVERNIGHT IS ERODING AS HIGHER
LEVEL MOISTURE ASSOCIATED WITH INCOMING TROUGH INCREASES. A FEW
POCKETS OF SURFACE VSBYS 3-5SM COULD PERSIST AROUND KOLM THROUGH
15Z. MAINLY VFR CEILINGS EXPECTED THIS MORNING...BUT MODELS INDICATE
THE LOW LEVELS WILL MOISTEN UP LATER TODAY WITH SOME HIGHER END MVFR
CEILINGS POSSIBLE MIDDAY INTO THE EVENING AS LIGHT PRECIP ASSOCIATED
WITH TROUGH MOVES INLAND.

KSEA...VFR CEILINGS EXPECTED THROUGH LATE MORNING...BUT MAY SEE SOME
TEMPO BKN-OVC030 WITH LIGHT RAIN 18Z-00Z. MVFR CEILINGS MAY STICK
AROUND TONIGHT WITH LIGHT SURFACE GRADIENTS AND MOIST AIR MASS IN
PLACE. EAST-SOUTHEAST WIND 5 TO 10 KNOTS...BECOMING LIGHT SOUTHERLY
TONIGHT.

&&

.MARINE...OFFSHORE GRADIENTS CONTINUE TO RELAX WITH A WEAK SURFACE
TROUGH APPROACHING THE COASTAL WATERS. SMALL CRAFT ADVISORIES
CONTINUE FOR THE OUTER COASTAL WATERS WHERE SEAS REMAIN NEAR 10
FEET. FOR THE REMAINDER OF THE WATERS...A PERIOD OF QUIET WEATHER IS
FORECAST TODAY WITH A WEAK SURFACE TROUGH OVER THE REGION. A BETTER
ORGANIZED AND STRONGER FRONT WILL APPROACH THE WATERS LATE THURSDAY.
A GALE WATCH FOR THE COASTAL WATERS MIDDAY THURSDAY THROUGH THURSDAY
NIGHT REMAINS IN EFFECT FOR THIS. ANOTHER FRONT ON SATURDAY COULD
PRODUCES GALES OVER THE NORTHERN INLAND WATERS...ENTRANCES TO THE
STRAIT OF JUAN DE FUCA...AND COASTAL WATERS. LONG PERIOD SWELL IN
EXCESS OF 20 FEET COULD REACH THE COAST ON FRIDAY. 27

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY TODAY FOR HAZARDOUS SEAS OUTER COASTAL
     WATERS.
     SMALL CRAFT ADVISORY TODAY FOR ROUGH GRAYS HARBOR BAR.
     GALE WATCH THURSDAY MORNING THROUGH LATE THURSDAY NIGHT FOR THE
     COASTAL WATERS.

&&

$$

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML








000
FXUS66 KSEW 171100
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 AM PST WED DEC 17 2014

.SYNOPSIS...A WEAK PACIFIC WEATHER SYSTEM WILL BRING SOME AREAS OF
LIGHT RAIN TO WESTERN WASHINGTON THROUGH WEDNESDAY NIGHT. A STRONGER
PACIFIC FRONTAL SYSTEM IS EXPECTED TO MOVE ASHORE THURSDAY NIGHT
WITH MORE SIGNIFICANT RAIN. ANOTHER WET WEATHER SYSTEM IS FORECAST
FOR THIS WEEKEND WITH HEAVIER RAIN AMOUNTS ALONG THE COAST AND IN
THE MOUNTAINS.

&&

.SHORT TERM...A NEGATIVE TILTED UPPER TROUGH WITH SPLIT FLOW IS JUST
OFF THE COAST EARLY THIS MORNING. THE PRIMARY FLOW ALOFT IS INTO
CALIFORNIA WHERE THE BULK OF THE PRECIP IS HEADED. A WEAKENING
SHORTWAVE WAS PRODUCING LIGHT RAIN ALONG THE COAST AND SOME OF THAT
SHOULD MOVE FURTHER INLAND LATER TODAY. RAIN AMOUNTS LIGHT THOUGH.

THE NEXT SHORTWAVE ON SATELITE IMAGERY WAS MOVING INSIDE 135W AGAIN
WITH THE BULK OF THE ENERGY HEADING TOWARD THE GOLDEN STATE. THE
REMAINING STRETCHED OUT PORTION AT OUR LATITUDE WILL LIKELY SPREAD
SOME ADDITIONAL LIGHT RAIN ONSHORE TONIGHT.

THE NEXT UPSTREAM AND STRONGER SHORTWAVE WAS NEAR 160W EARLY THIS
MORNING. THIS SYSTEM WAS PUMPING UP A SHORTWAVE RIDGE AHEAD OF IT
THAT PROGS AGREE WILL MOVE ONSHORE THURSDAY. THEN THE ASSOCIATED
FRONTAL SYSTEM SHOULD BEGIN TO SPREAD RAIN ONSHORE LATE THURSDAY
WITH THE COLD FRONT MOVING INLAND EARLY FRIDAY. BLUSTERY WINDS FOR
THE COAST AND NORTH INTERIOR WITH THIS SYSTEM. THE SHORTWAVE TROUGH
IS THEN FORECAST TO MOVE ASHORE FOR A BIT COOLER SHOWERY DAY FRIDAY.

FOR THE MOUNTAINS...THE LACK OF SNOW IS A CONCERN. THE WEATHER
SYSTEMS TODAY THROUGH FRIDAY SHOULD PRODUCE AT LEAST SOME SNOWFALL
THERE. EAST TO WEST GRADIENTS ACROSS THE CASCADES SHOULD TEND TO
KEEP THE SNOW LEVELS CLOSE TO THE PASSES UNTIL THE THURSDAY NIGHT
SYSTEM MOVES ONSHORE EARLY FRIDAY. BY THEN...THE FOLLOWING SHORTWAVE
TROUGH WILL BRING SOME COOLER UNSTABLE AIR FOR SNOW SHOWERS. NOT A
WHOLE LOT OF SNOW IN THE NEXT 3 DAYS...BUT BETTER THAN LAST WEEKS
MILD WET WEATHER. BUEHNER

.LONG TERM...LOOKS LIKE A SHORT BREAK IN THE WEATHER FRIDAY NIGHT
BEFORE THE NEXT WETTER SYSTEM ARRIVES OVER THE WEEKEND. THIS SYSTEM
WAS CURRENTLY MOVING ACROSS 150E THIS MORNING WITH A SUPPORTING 200
KT JET. THE PROGS ARE STILL TRENDING A BIT DRIER WITH THIS SYSTEM
GIVEN ITS MORE PROGRESSIVE NATURE. EXPECT RAIN TO INCREASE ON
SATURDAY WITH THE WARM FRONT AND THE COLD FRONT MOVING ONSHORE
SUNDAY NIGHT.

RIDGING ALOFT ALONG THE WEST COAST MEANS THE JET STREAM WILL BE AT
OUR LATITUDE WITH A WESTERLY COMPONENT INTO THE CASCADES AND
SHADOWING OFF THE OLYMPICS THIS WEEKEND. THE COAST AND MOUNTAINS
SHOULD GET THE BULK OF THE PRECIPITATION.

ANOTHER SHORT BREAK MONDAY BEFORE THE NEXT NOT AS WET SYSTEM ARRIVES
TUESDAY. THE PROGS CONTINUE TO SUGGEST A KONA LOW DEVELOPING BUT
THEY ARE INCONSISTENT IN ITS POSITION. THE FURTHER WEST USUALLY
RESULTS IN BUILDING AN UPPER RIDGE NEAR 150W OR 160W AND PRODUCING
NORTHERLY FLOW ALOFT INTO THE PACIFIC NW FOR A MUCH COOLER FLOW
PATTERN. FURTHER EAST WITH THE PATTERN AND THE PACIFIC NW GETS A
MILDER NORTHERLY FLOW ALOFT. STAY TUNED HERE. BUEHNER

&&

.HYDROLOGY...RIVER FLOODING IS NOT EXPECTED THROUGH SATURDAY. MOIST
WESTERLY FLOW WILL DEVELOP SATURDAY NIGHT AND CONTINUE THROUGH
SUNDAY NIGHT...WITH HEAVY MOUNTAIN RAIN AMOUNTS POSSIBLE.
GUIDANCE IS NOW SHOWING A BIT LIGHTER AMOUNTS GIVEN THE MORE
PROGRESSIVE NATURE OF THIS SYSTEM. PRIMARY CONCERN FOR ANY RIVER
RISING ABOVE FLOOD STAGE IS THE SKOKOMISH BUT ALSO NEED TO KEEP AN
EYE ON OTHER CASCADE FLOOD PRONE STREAMS. BUEHNER

&&

.AVIATION...AN UPPER LEVEL TROUGH WILL GIVE LIGHT SOUTHWEST FLOW
ALOFT OVER WESTERN WASHINGTON TODAY. LOW LEVEL OFFSHORE FLOW WILL
EASE AS A SURFACE TROUGH MOVES ONSHORE AND RIDGING EAST OF THE
CASCADES WEAKENS. THE AIR MASS WILL REMAIN MOIST AND STABLE WITH
AREAS OF VERY LIGHT PRECIPITATION MOVING THROUGH AT TIMES.

STRATUS OVER THE SOUTHWEST INTERIOR OVERNIGHT IS ERODING AS HIGHER
LEVEL MOISTURE ASSOCIATED WITH INCOMING TROUGH INCREASES. A FEW
POCKETS OF SURFACE VSBYS 3-5SM COULD PERSIST AROUND KOLM THROUGH
15Z. MAINLY VFR CEILINGS EXPECTED THIS MORNING...BUT MODELS INDICATE
THE LOW LEVELS WILL MOISTEN UP LATER TODAY WITH SOME HIGHER END MVFR
CEILINGS POSSIBLE MIDDAY INTO THE EVENING AS LIGHT PRECIP ASSOCIATED
WITH TROUGH MOVES INLAND.

KSEA...VFR CEILINGS EXPECTED THROUGH LATE MORNING...BUT MAY SEE SOME
TEMPO BKN-OVC030 WITH LIGHT RAIN 18Z-00Z. MVFR CEILINGS MAY STICK
AROUND TONIGHT WITH LIGHT SURFACE GRADIENTS AND MOIST AIR MASS IN
PLACE. EAST-SOUTHEAST WIND 5 TO 10 KNOTS...BECOMING LIGHT SOUTHERLY
TONIGHT.

&&

.MARINE...OFFSHORE GRADIENTS CONTINUE TO RELAX WITH A WEAK SURFACE
TROUGH APPROACHING THE COASTAL WATERS. SMALL CRAFT ADVISORIES
CONTINUE FOR THE OUTER COASTAL WATERS WHERE SEAS REMAIN NEAR 10
FEET. FOR THE REMAINDER OF THE WATERS...A PERIOD OF QUIET WEATHER IS
FORECAST TODAY WITH A WEAK SURFACE TROUGH OVER THE REGION. A BETTER
ORGANIZED AND STRONGER FRONT WILL APPROACH THE WATERS LATE THURSDAY.
A GALE WATCH FOR THE COASTAL WATERS MIDDAY THURSDAY THROUGH THURSDAY
NIGHT REMAINS IN EFFECT FOR THIS. ANOTHER FRONT ON SATURDAY COULD
PRODUCES GALES OVER THE NORTHERN INLAND WATERS...ENTRANCES TO THE
STRAIT OF JUAN DE FUCA...AND COASTAL WATERS. LONG PERIOD SWELL IN
EXCESS OF 20 FEET COULD REACH THE COAST ON FRIDAY. 27

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY TODAY FOR HAZARDOUS SEAS OUTER COASTAL
     WATERS.
     SMALL CRAFT ADVISORY TODAY FOR ROUGH GRAYS HARBOR BAR.
     GALE WATCH THURSDAY MORNING THROUGH LATE THURSDAY NIGHT FOR THE
     COASTAL WATERS.

&&

$$

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML









000
FXUS66 KPQR 171059
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
259 AM PST WED DEC 17 2014

.SYNOPSIS...A CLOSED LOW JUST OFFSHORE WEST OF THE OR/CA BORDER WILL
SLOWLY WEAKEN AND EVENTUALLY MOVE ONSHORE ALONG THE N OR/S WA COAST
THIS AFTERNOON. THIS WILL MAINTAIN LIGHT SHOWER ACTIVITY...MAINLY
OVER THE HIGHER TERRAIN THIS MORNING. AN UPPER LEVEL SHORTWAVE WILL
PUSH ONSHORE LATER TODAY...LIKELY BRINGING A PERIOD OF STEADIER
RAINFALL THROUGH EARLY THU MORNING. EXPECT A FAIRLY QUIET PERIOD FOR
MUCH OF THE DAY THU...BUT THEN A MORE ORGANIZED FRONT WILL BRING
GUSTY WINDS AND LARGE SURF TO THE COAST...WITH RAIN SPREADING INLAND
THURSDAY NIGHT AND FRIDAY. RISING SNOW LEVELS WILL LIMIT SNOW TO THE
HIGHEST PEAKS...BUT COLDER AIR BEHIND THE FRONT MAY RESULT IN SOME
SNOW SHOWERS FOR THE CASCADES PASSES FRIDAY EVENING AND SATURDAY.
WARMER AND MOISTER WEATHER IS EXPECTED THIS WEEKEND. THERE IS THE
POTENTIAL FOR AN ATMOSPHERIC RIVER TYPE SET UP AND ASSOCIATED HEAVY
RAIN TO DEVELOP OVER THE WEEKEND INTO EARLY NEXT WEEK.

&&

.SHORT TERM...TODAY THROUGH SATURDAY...VERY LIGHT RAIN CONTINUES TO
IMPACT SW WASHINGTON THIS MORNING BUT HAS OTHERWISE STARTED TO
DISSIPATE OVER THE SOUTHERN PORTION OF THE FORECAST AREA. WATER VAPOR
IMAGERY SHOWS A CLOSED LOW WEAKENING AS IT HAS PUSHED ONSHORE NEAR
THE OREGON/CALIFORNIA BORDER...WHILE AN UPPER LEVEL SHORTWAVE IS
ELONGATING AS IT APPROACHES THE PACIFIC NORTHWEST COASTLINE. NOT MUCH
CHANGE IN THE KTTD-KDLS GRADIENT...WHICH REMAINS AROUND -5 EARLY THIS
MORNING. EAST WINDS CONTINUE TO GUST NEAR 25 MPH THROUGH THE
GORGE...BUT EXPECT THE EASTERLY GRADIENT TO WEAKEN BY LATE TONIGHT.

AFTER A PERIOD OF LIGHT RAIN THIS MORNING...MODELS REMAIN CONSISTENT
IN SHOWING AN UPTICK IN PRECIP BY THIS AFTERNOON ASSOCIATED WITH THE
VORT MAX JUST OFFSHORE AROUND 45N 134W. THE LOWER LEVEL MOISTURE
ASSOCIATED WITH THE SURFACE LOW COMBINED WITH THE UPPER LEVEL FORCING
FROM THE SHORTWAVE SHOULD DRIVE A PERIOD OF STEADIER PRECIP THIS
EVENING AND THROUGH TONIGHT. THE VORT MAX PUSHES EAST OF THE CASCADES
BY 12Z THU...AFTER WHICH SHOWER ACTIVITY SHOULD DROP OFF
SIGNIFICANTLY.

WITH CLEARING SKIES AND LIGHT WINDS...SHOULD SEE SOME SHALLOW FOG TO
DEVELOP IN INTERIOR VALLEYS TONIGHT THROUGH EARLY THU MORNING. MODELS
MAINTAIN A THREAT FOR LIGHT PRECIP OVER THE HIGHER TERRAIN MUCH OF
THU...BUT OTHERWISE EXPECT DRY CONDITIONS TO PERSIST TO LOWER
ELEVATIONS. THE NEXT SIGNIFICANT FRONTAL SYSTEM ARRIVES LATE
THU...SPREADING RAIN AND BRINGING GUSTY COASTAL WINDS TO THE REGION
THROUGH FRI. PRECIPITABLE WATER IS EXPECTED TO BE NEAR AN INCH AND AN
APPROACHING JET STREAK SHOULD PROVIDE GOOD LIFT AND EXPECT THE
HIGHEST RAINFALL TOTALS OF 0.75 TO 1 INCH ACROSS THE COAST AND COAST
RANGE THROUGH MIDDAY FRI. OTHER LOCATIONS WILL SEE ON AVERAGE 0.5
INCHES OF RAIN. SNOW LEVELS SHOULD REMAIN ABOVE 5000 FEET DURING THE
PEAK RAIN PERIOD...BUT LOWER TO NEAR OR BELOW THE CASCADE PASSES
BEHIND THE FRONT FRIDAY AFTERNOON.

STRONG LOW PRESSURE OVER THE GULF OF ALASKA WILL PUSH INLAND LATE FRI
INTO EARLY SAT MORNING...SIMULTANEOUSLY FLATTENING A BROAD AREA OF
HIGH PRESSURE OVER THE EASTERN PACIFIC. THERE IS INCREASING
CONFIDENCE AN ATMOSPHERIC RIVER SCENARIO WILL SET UP...WITH ABUNDANT
MOISTURE AIMED DIRECTLY AT THE PACIFIC NORTHWEST SAT.

.LONG TERM...SATURDAY NIGHT THROUGH TUESDAY...AS THIS TROUGH MOVES ON
SHORE SATURDAY...THE ASSOCIATED COLD FRONT MOVES ONSHORE AND STALLS
EAST-TO-WEST ACROSS NORTHWEST OREGON AND SOUTHWEST WASHINGTON. THIS
PUTS OUR AREA IN THE PATH OF RAIN STARTING SATURDAY THROUGH MONDAY.
SOME UNCERTAINTY EXISTS IN WHERE THIS BOUNDARY WILL SET UP...WHICH
WILL DETERMINE HOW MUCH RAINFALL WE WILL GET. ON TUESDAY...GEFS
ENSEMBLE SPAGHETTI PLOTS GET MESSY AND SIGNIFICANT DIFFERENCES START
TO SHOW UP BETWEEN THE GFS AND ECMWF...DECREASING CONFIDENCE ON HOW
THE REST OF THE WEEK WILL SHAPE UP.  AS OF NOW...THE MOST COMMON
SOLUTION IS THAT HIGH PRESSURE RIDGING WILL START TO BUILD BACK OVER
THE WESTERN U.S. WHICH SUGGESTS DRIER WEATHER STARTING TUESDAY...
THOUGH UNCERTAINTY IS VERY HIGH. -MCCOY

&&

.AVIATION...VFR CONDITIONS TO PERSIST AT MOST TAF SITES THROUGH
WEDNESDAY AFTERNOON. THE QUESTION STILL REMAINS WHETHER LOW LEVEL
STRATUS/FOG WILL DEVELOP IN THE CENTRAL AND SOUTH WILLAMETTE
VALLEY. IF LOW LEVEL STRATUS/FOG DOES DEVELOP EXPECT IT TO CLEAR
OUT BY EARLY WEDNESDAY AFTERNOON. BRIEF PERIODS OF MVFR TO IFR
CIGS AND VIS ARE POSSIBLE UNDER LIGHT TO MODERATE RAIN BANDS
THROUGH LATE WEDNESDAY. WITH CLEARING EXPECTED LATE WEDNESDAY WE
WILL LIKELY SEE THE DEVELOPMENT OF IFR CIGS AND VIS DUE TO LOW
LEVEL STRATUS/FOG RETURNING TO PORTIONS OF THE VALLEY.

KPDX AND APPROACHES...VFR CONDITIONS TO PERSIST WEDNESDAY.
HOWEVER...BRIEF PERIODS OF MVFR CIGS AND VIS ARE POSSIBLE UNDER
LIGHT TO MODERATE RAIN BANDS THROUGH WEDNESDAY AFTERNOON. /64

&&

.MARINE...RATHER BENIGN CONDITIONS TO CONTINUE THROUGH EARLY
THURSDAY AS A WEAK LOW PRESSURE SYSTEM MOVES INLAND OVER NORTHERN
CALIFORNIA. EXPECT SEAS TO REMAIN BELOW 10 FT WITH GUST TO 20 KT
POSSIBLE. ANOTHER LOW PRESSURE SYSTEM CONTINUES TO STRENGTHEN
OFFSHORE AND LOOKS TO MOVE ACROSS THE COASTAL WATERS ON THURSDAY.
THIS SYSTEM WILL LIKELY BRING SOUTHERLY GALES THURSDAY THROUGH
EARLY FRIDAY...BUT THERE IS STILL SOME UNCERTAINTY ON THE EXACT
TIMING. SEAS WITH THIS SYSTEM ARE EXPECTED TO BUILD INTO THE UPPER
TEENS TO THE LOW 20S BY SATURDAY MORNING. AN ACTIVE WEATHER
PATTERN WILL CONTINUE THROUGH NEXT WEEK AND COULD BRING MORE
SOUTHERLY GALES AND ELEVATED SEAS. /64

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.

WA...NONE.

PZ...GALE WATCH FROM THURSDAY MORNING THROUGH THURSDAY EVENING FOR
     COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT
     60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 11 AM
    THIS MORNING TO 4 PM PST THIS AFTERNOON.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.




000
FXUS66 KOTX 171024
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
223 AM PST WED DEC 17 2014

.SYNOPSIS...
A more active weather pattern will develop through the week with
periods of light snow in the mountains...and rain or snow in the
valleys. Lower elevations from Interstate 90 south will see mainly
rain...while areas in the Cascades and near the Canadian border
will remain mainly snow. A much stronger weather system over the
weekend will usher in warmer temperatures with sharply rising snow
levels...as well as the potential for windy conditions.


&&

.DISCUSSION...
Today through Thursday night...The region will continue to be
under the influence of a split and ragged upper level trough
today and tonight. Again a couple of weak waves will move through
the forecast area and result in periods of light precipitation.
Cooler air banked up against the Cascades continues to make snow
level forecast a challenge. The 00z guidance came in with wet bulb
temperatures down around 30F when in fact the wet bulbs are in the
low to mid 30s. I most likely kept snow levels a little to low
across the areas for this morning, otherwise snow levels are
anywhere from 2500 to around 4000 feet across the area. So any
precipitation will be valley rain...possibly mixed with a little
snow for the Methow and up near Ardnevoir and mountain snow.
Precipitation amounts will remain light with a few hundredths in
the basin and lower valleys and possibly up to a tenth in the
mountains. Snow accumulations even for the mountains will only be
an inch or two.

Precipitation chances will then be on the decrease from the west
for the remainder of the night and Thursday as a short lived ridge
of high pressure builds into the region. Some pops were kept in
the orographically favored Panhandle mountains, but again
accumulations should remain light with light snow above 3500 feet
for the Panhandle. Fog and stratus will likely develop through
the night and Thursday morning with a saturated boundary layer and
light south-southwest winds.

The next system will move towards the region Thursday night and
increase Pacific moisture. Snow levels for the valleys near the
Cascades will again be problematic. I don`t see any freezing rain
at this time but precipitation probably as a snow or snow/rain mix
for those valleys and snow above 3000-3500 feet. Some of the
higher locations in the Cascades could see 3-5 inches of fresh
snow by early Friday morning. Tobin

Friday and Friday night...The next in a series of Pacific weather
systems pushes across the Inland Northwest on Friday with a warm
front followed closely by an occluded front Friday evening. This
one looks to be a little stronger and a little warmer.
Precipitation type will be tricky with light snow in the morning,
turning to valley rain and mountain snow by afternoon. There looks
to be the potential for up to an inch in the northern valleys,
while the northern mountains could see 1-3 inches. Drying occurs
behind the front Friday night with a brief break in the
precipitation and light winds.

Saturday through Sunday night...This still looks to be a wettest
period as an atmospheric river takes aim on the Pacific NW. The
GFS and ECMWF show agreement of moderate isentropic lift spreading
across the region Saturday morning with a stream of plentiful
moisture for most of the weekend. Again precipitation type will be
tricky, initially with valley snow possible in the valley northern
valleys especially in the Cascade valleys. Warming increases
Saturday night into Sunday, making it a mainly rain/high mountain
snow event by Sunday afternoon. The 850mb 0C line pushes to the
Canadian border on Sunday while temps of +5C to +7C poke into the
Columbia Basin. Sunday appears to be the warmest day with
widespread 40s and a few 50s possible. Moderate to heavy rainfall
is possible with juicy QPF amounts of 0.25" to 0.40" during a 24
hour period Saturday night into Sunday. Winds will increase by
Sunday evening with speeds 25-35 kts across the Columbia Basin.
Could even see some gusty mountain winds across the Cascades by
Sunday night. POPs and QPF amounts have been raised and winds
bumped for this period.

Monday through Tuesday...A cold front slides through the region
Monday allowing the atmospheric river to sag southward and cooler
drier air to filter in from the north. The bulk of the precipitation
will be found in the Cascades and Panhandle mountains through
Monday morning and then gradually taper off. Drier conditions and
clearing will allow temperatures to cool Monday night. This will
set the stage for the next weather system. Under the northwest
flow aloft, a disturbance is expected to drop down from the Gulf
of Alaska. A warm front will spread light precipitation across
eastern Washington by Tuesday. Based on low level temperatures,
there is good chance that the precipitation type will start off as
snow for most areas. /rfox.

&&

.AVIATION...
06Z TAFS: Lingering snow showers or flurries will continue
overnight north of the Spokane/Coeur d`Alene corridor. Fog and
stratus that developed across this area is already beginning to
lift as drier northeasterly winds scour out this low level
moisture. There will continue to be a slight chance for some
patchy fog tonight at KGEG, KSFF and KCOE, but the trend is for
improving flight conditions overnight. The same cannot be said
for KMWH and KEAT which will see a stratus deck through the
overnight hours into Wednesday. Another shortwave disturbance
will push across the region on Wednesday. Light rain is expected
at KEAT and KMWH by the morning hours with light rain developing
at KGEG, KSFF and KCOE in the afternoon. /SVH

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        39  32  37  32  39  31 /  20  40  30  20  80  20
Coeur d`Alene  39  33  38  33  39  32 /  10  50  60  20  80  30
Pullman        43  33  43  34  42  29 /  10  50  40  10  70  20
Lewiston       43  35  45  36  44  31 /  10  40  30  10  60  20
Colville       35  32  37  33  38  32 /  20  50  30  50  80  20
Sandpoint      37  32  37  31  36  32 /  20  60  60  30  80  30
Kellogg        37  32  38  31  36  31 /  10  70  70  20  80  40
Moses Lake     39  29  39  32  42  28 /  20  20  10  60  60  10
Wenatchee      38  31  37  32  40  30 /  50  30  10  70  50  10
Omak           34  27  34  30  37  27 /  40  40  10  70  80  10

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$




000
FXUS66 KOTX 171024
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
223 AM PST WED DEC 17 2014

.SYNOPSIS...
A more active weather pattern will develop through the week with
periods of light snow in the mountains...and rain or snow in the
valleys. Lower elevations from Interstate 90 south will see mainly
rain...while areas in the Cascades and near the Canadian border
will remain mainly snow. A much stronger weather system over the
weekend will usher in warmer temperatures with sharply rising snow
levels...as well as the potential for windy conditions.


&&

.DISCUSSION...
Today through Thursday night...The region will continue to be
under the influence of a split and ragged upper level trough
today and tonight. Again a couple of weak waves will move through
the forecast area and result in periods of light precipitation.
Cooler air banked up against the Cascades continues to make snow
level forecast a challenge. The 00z guidance came in with wet bulb
temperatures down around 30F when in fact the wet bulbs are in the
low to mid 30s. I most likely kept snow levels a little to low
across the areas for this morning, otherwise snow levels are
anywhere from 2500 to around 4000 feet across the area. So any
precipitation will be valley rain...possibly mixed with a little
snow for the Methow and up near Ardnevoir and mountain snow.
Precipitation amounts will remain light with a few hundredths in
the basin and lower valleys and possibly up to a tenth in the
mountains. Snow accumulations even for the mountains will only be
an inch or two.

Precipitation chances will then be on the decrease from the west
for the remainder of the night and Thursday as a short lived ridge
of high pressure builds into the region. Some pops were kept in
the orographically favored Panhandle mountains, but again
accumulations should remain light with light snow above 3500 feet
for the Panhandle. Fog and stratus will likely develop through
the night and Thursday morning with a saturated boundary layer and
light south-southwest winds.

The next system will move towards the region Thursday night and
increase Pacific moisture. Snow levels for the valleys near the
Cascades will again be problematic. I don`t see any freezing rain
at this time but precipitation probably as a snow or snow/rain mix
for those valleys and snow above 3000-3500 feet. Some of the
higher locations in the Cascades could see 3-5 inches of fresh
snow by early Friday morning. Tobin

Friday and Friday night...The next in a series of Pacific weather
systems pushes across the Inland Northwest on Friday with a warm
front followed closely by an occluded front Friday evening. This
one looks to be a little stronger and a little warmer.
Precipitation type will be tricky with light snow in the morning,
turning to valley rain and mountain snow by afternoon. There looks
to be the potential for up to an inch in the northern valleys,
while the northern mountains could see 1-3 inches. Drying occurs
behind the front Friday night with a brief break in the
precipitation and light winds.

Saturday through Sunday night...This still looks to be a wettest
period as an atmospheric river takes aim on the Pacific NW. The
GFS and ECMWF show agreement of moderate isentropic lift spreading
across the region Saturday morning with a stream of plentiful
moisture for most of the weekend. Again precipitation type will be
tricky, initially with valley snow possible in the valley northern
valleys especially in the Cascade valleys. Warming increases
Saturday night into Sunday, making it a mainly rain/high mountain
snow event by Sunday afternoon. The 850mb 0C line pushes to the
Canadian border on Sunday while temps of +5C to +7C poke into the
Columbia Basin. Sunday appears to be the warmest day with
widespread 40s and a few 50s possible. Moderate to heavy rainfall
is possible with juicy QPF amounts of 0.25" to 0.40" during a 24
hour period Saturday night into Sunday. Winds will increase by
Sunday evening with speeds 25-35 kts across the Columbia Basin.
Could even see some gusty mountain winds across the Cascades by
Sunday night. POPs and QPF amounts have been raised and winds
bumped for this period.

Monday through Tuesday...A cold front slides through the region
Monday allowing the atmospheric river to sag southward and cooler
drier air to filter in from the north. The bulk of the precipitation
will be found in the Cascades and Panhandle mountains through
Monday morning and then gradually taper off. Drier conditions and
clearing will allow temperatures to cool Monday night. This will
set the stage for the next weather system. Under the northwest
flow aloft, a disturbance is expected to drop down from the Gulf
of Alaska. A warm front will spread light precipitation across
eastern Washington by Tuesday. Based on low level temperatures,
there is good chance that the precipitation type will start off as
snow for most areas. /rfox.

&&

.AVIATION...
06Z TAFS: Lingering snow showers or flurries will continue
overnight north of the Spokane/Coeur d`Alene corridor. Fog and
stratus that developed across this area is already beginning to
lift as drier northeasterly winds scour out this low level
moisture. There will continue to be a slight chance for some
patchy fog tonight at KGEG, KSFF and KCOE, but the trend is for
improving flight conditions overnight. The same cannot be said
for KMWH and KEAT which will see a stratus deck through the
overnight hours into Wednesday. Another shortwave disturbance
will push across the region on Wednesday. Light rain is expected
at KEAT and KMWH by the morning hours with light rain developing
at KGEG, KSFF and KCOE in the afternoon. /SVH

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        39  32  37  32  39  31 /  20  40  30  20  80  20
Coeur d`Alene  39  33  38  33  39  32 /  10  50  60  20  80  30
Pullman        43  33  43  34  42  29 /  10  50  40  10  70  20
Lewiston       43  35  45  36  44  31 /  10  40  30  10  60  20
Colville       35  32  37  33  38  32 /  20  50  30  50  80  20
Sandpoint      37  32  37  31  36  32 /  20  60  60  30  80  30
Kellogg        37  32  38  31  36  31 /  10  70  70  20  80  40
Moses Lake     39  29  39  32  42  28 /  20  20  10  60  60  10
Wenatchee      38  31  37  32  40  30 /  50  30  10  70  50  10
Omak           34  27  34  30  37  27 /  40  40  10  70  80  10

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 170551
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
951 PM PST TUE DEC 16 2014

.SYNOPSIS...
A more active weather pattern will develop through the week with
periods of light snow in the mountains...and rain or snow in the
valleys. Lower elevations from Interstate 90 south will see mainly
rain...while areas in the Cascades and near the Canadian border
will remain mainly snow. A much stronger weather system over the
weekend will usher in warmer temperatures with sharply rising snow
levels...as well as the potential for windy conditions.


&&

.DISCUSSION...
Evening forecast update to increase precip chances, decrease snow
levels and increase overnight low temperatures. Increased moist
isentropic ascent out ahead of a weak upper level feature has
resulted in widespread light snowfall along and north of the
Highway 2 corridor. Snowflakes will be very fine and contain
have a small moisture content; as a result, I do not anticipated
much if any accumulations from the snow. Best chances for
accumulations will be on grassy surfaces across the northern
mountains where less than a half of an inch will fall over most
locations. Snow will begin to push north of the Spokane/Coeur
d`Alene corridor late this evening.

With current dew point temperatures in the low to mid 30s across
the basin early this evening, I increase low temperatures a bit
warming them into the 30s for most locations. Fog will be possible
due how moist the boundary layer is. Easterly winds may result in
less fog in the Panhandle and portions of extreme easter WA with
better chances for a foggy morning expected in the western basin,
Cascade valleys and northern mtn valleys. /SVH


&&

.AVIATION...
06Z TAFS: Lingering snow showers or flurries will continue
overnight north of the Spokane/Coeur d`Alene corridor. Fog and
stratus that developed across this area is already beginning to
lift as drier northeasterly winds scour out this low level
moisture. There will continue to be a slight chance for some
patchy fog tonight at KGEG, KSFF and KCOE, but the trend is for
improving flight conditions overnight. The same cannot be said
for KMWH and KEAT which will see a stratus deck through the
overnight hours into Wednesday. Another shortwave disturbance
will push across the region on Wednesday. Light rain is expected
at KEAT and KMWH by the morning hours with light rain developing
at KGEG, KSFF and KCOE in the afternoon. /SVH


&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        30  38  33  36  33  38 /  70  30  40  30  20  70
Coeur d`Alene  30  40  33  37  31  38 /  60  30  50  50  20  70
Pullman        32  42  34  42  33  41 /  10  10  50  30  20  70
Lewiston       34  42  35  45  34  43 /  10  10  40  30  10  50
Colville       30  36  33  37  33  37 /  70  30  40  30  50  70
Sandpoint      29  36  33  37  30  36 /  50  30  60  60  20  80
Kellogg        31  38  32  38  29  37 /  20  10  70  60  20  70
Moses Lake     32  38  29  38  34  41 /  10  30  20  10  60  50
Wenatchee      34  37  30  37  33  40 /  50  30  30  10  60  50
Omak           29  34  28  34  32  37 /  70  40  40  10  70  60

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 170551
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
951 PM PST TUE DEC 16 2014

.SYNOPSIS...
A more active weather pattern will develop through the week with
periods of light snow in the mountains...and rain or snow in the
valleys. Lower elevations from Interstate 90 south will see mainly
rain...while areas in the Cascades and near the Canadian border
will remain mainly snow. A much stronger weather system over the
weekend will usher in warmer temperatures with sharply rising snow
levels...as well as the potential for windy conditions.


&&

.DISCUSSION...
Evening forecast update to increase precip chances, decrease snow
levels and increase overnight low temperatures. Increased moist
isentropic ascent out ahead of a weak upper level feature has
resulted in widespread light snowfall along and north of the
Highway 2 corridor. Snowflakes will be very fine and contain
have a small moisture content; as a result, I do not anticipated
much if any accumulations from the snow. Best chances for
accumulations will be on grassy surfaces across the northern
mountains where less than a half of an inch will fall over most
locations. Snow will begin to push north of the Spokane/Coeur
d`Alene corridor late this evening.

With current dew point temperatures in the low to mid 30s across
the basin early this evening, I increase low temperatures a bit
warming them into the 30s for most locations. Fog will be possible
due how moist the boundary layer is. Easterly winds may result in
less fog in the Panhandle and portions of extreme easter WA with
better chances for a foggy morning expected in the western basin,
Cascade valleys and northern mtn valleys. /SVH


&&

.AVIATION...
06Z TAFS: Lingering snow showers or flurries will continue
overnight north of the Spokane/Coeur d`Alene corridor. Fog and
stratus that developed across this area is already beginning to
lift as drier northeasterly winds scour out this low level
moisture. There will continue to be a slight chance for some
patchy fog tonight at KGEG, KSFF and KCOE, but the trend is for
improving flight conditions overnight. The same cannot be said
for KMWH and KEAT which will see a stratus deck through the
overnight hours into Wednesday. Another shortwave disturbance
will push across the region on Wednesday. Light rain is expected
at KEAT and KMWH by the morning hours with light rain developing
at KGEG, KSFF and KCOE in the afternoon. /SVH


&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        30  38  33  36  33  38 /  70  30  40  30  20  70
Coeur d`Alene  30  40  33  37  31  38 /  60  30  50  50  20  70
Pullman        32  42  34  42  33  41 /  10  10  50  30  20  70
Lewiston       34  42  35  45  34  43 /  10  10  40  30  10  50
Colville       30  36  33  37  33  37 /  70  30  40  30  50  70
Sandpoint      29  36  33  37  30  36 /  50  30  60  60  20  80
Kellogg        31  38  32  38  29  37 /  20  10  70  60  20  70
Moses Lake     32  38  29  38  34  41 /  10  30  20  10  60  50
Wenatchee      34  37  30  37  33  40 /  50  30  30  10  60  50
Omak           29  34  28  34  32  37 /  70  40  40  10  70  60

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 170551
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
951 PM PST TUE DEC 16 2014

.SYNOPSIS...
A more active weather pattern will develop through the week with
periods of light snow in the mountains...and rain or snow in the
valleys. Lower elevations from Interstate 90 south will see mainly
rain...while areas in the Cascades and near the Canadian border
will remain mainly snow. A much stronger weather system over the
weekend will usher in warmer temperatures with sharply rising snow
levels...as well as the potential for windy conditions.


&&

.DISCUSSION...
Evening forecast update to increase precip chances, decrease snow
levels and increase overnight low temperatures. Increased moist
isentropic ascent out ahead of a weak upper level feature has
resulted in widespread light snowfall along and north of the
Highway 2 corridor. Snowflakes will be very fine and contain
have a small moisture content; as a result, I do not anticipated
much if any accumulations from the snow. Best chances for
accumulations will be on grassy surfaces across the northern
mountains where less than a half of an inch will fall over most
locations. Snow will begin to push north of the Spokane/Coeur
d`Alene corridor late this evening.

With current dew point temperatures in the low to mid 30s across
the basin early this evening, I increase low temperatures a bit
warming them into the 30s for most locations. Fog will be possible
due how moist the boundary layer is. Easterly winds may result in
less fog in the Panhandle and portions of extreme easter WA with
better chances for a foggy morning expected in the western basin,
Cascade valleys and northern mtn valleys. /SVH


&&

.AVIATION...
06Z TAFS: Lingering snow showers or flurries will continue
overnight north of the Spokane/Coeur d`Alene corridor. Fog and
stratus that developed across this area is already beginning to
lift as drier northeasterly winds scour out this low level
moisture. There will continue to be a slight chance for some
patchy fog tonight at KGEG, KSFF and KCOE, but the trend is for
improving flight conditions overnight. The same cannot be said
for KMWH and KEAT which will see a stratus deck through the
overnight hours into Wednesday. Another shortwave disturbance
will push across the region on Wednesday. Light rain is expected
at KEAT and KMWH by the morning hours with light rain developing
at KGEG, KSFF and KCOE in the afternoon. /SVH


&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        30  38  33  36  33  38 /  70  30  40  30  20  70
Coeur d`Alene  30  40  33  37  31  38 /  60  30  50  50  20  70
Pullman        32  42  34  42  33  41 /  10  10  50  30  20  70
Lewiston       34  42  35  45  34  43 /  10  10  40  30  10  50
Colville       30  36  33  37  33  37 /  70  30  40  30  50  70
Sandpoint      29  36  33  37  30  36 /  50  30  60  60  20  80
Kellogg        31  38  32  38  29  37 /  20  10  70  60  20  70
Moses Lake     32  38  29  38  34  41 /  10  30  20  10  60  50
Wenatchee      34  37  30  37  33  40 /  50  30  30  10  60  50
Omak           29  34  28  34  32  37 /  70  40  40  10  70  60

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 170551
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
951 PM PST TUE DEC 16 2014

.SYNOPSIS...
A more active weather pattern will develop through the week with
periods of light snow in the mountains...and rain or snow in the
valleys. Lower elevations from Interstate 90 south will see mainly
rain...while areas in the Cascades and near the Canadian border
will remain mainly snow. A much stronger weather system over the
weekend will usher in warmer temperatures with sharply rising snow
levels...as well as the potential for windy conditions.


&&

.DISCUSSION...
Evening forecast update to increase precip chances, decrease snow
levels and increase overnight low temperatures. Increased moist
isentropic ascent out ahead of a weak upper level feature has
resulted in widespread light snowfall along and north of the
Highway 2 corridor. Snowflakes will be very fine and contain
have a small moisture content; as a result, I do not anticipated
much if any accumulations from the snow. Best chances for
accumulations will be on grassy surfaces across the northern
mountains where less than a half of an inch will fall over most
locations. Snow will begin to push north of the Spokane/Coeur
d`Alene corridor late this evening.

With current dew point temperatures in the low to mid 30s across
the basin early this evening, I increase low temperatures a bit
warming them into the 30s for most locations. Fog will be possible
due how moist the boundary layer is. Easterly winds may result in
less fog in the Panhandle and portions of extreme easter WA with
better chances for a foggy morning expected in the western basin,
Cascade valleys and northern mtn valleys. /SVH


&&

.AVIATION...
06Z TAFS: Lingering snow showers or flurries will continue
overnight north of the Spokane/Coeur d`Alene corridor. Fog and
stratus that developed across this area is already beginning to
lift as drier northeasterly winds scour out this low level
moisture. There will continue to be a slight chance for some
patchy fog tonight at KGEG, KSFF and KCOE, but the trend is for
improving flight conditions overnight. The same cannot be said
for KMWH and KEAT which will see a stratus deck through the
overnight hours into Wednesday. Another shortwave disturbance
will push across the region on Wednesday. Light rain is expected
at KEAT and KMWH by the morning hours with light rain developing
at KGEG, KSFF and KCOE in the afternoon. /SVH


&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        30  38  33  36  33  38 /  70  30  40  30  20  70
Coeur d`Alene  30  40  33  37  31  38 /  60  30  50  50  20  70
Pullman        32  42  34  42  33  41 /  10  10  50  30  20  70
Lewiston       34  42  35  45  34  43 /  10  10  40  30  10  50
Colville       30  36  33  37  33  37 /  70  30  40  30  50  70
Sandpoint      29  36  33  37  30  36 /  50  30  60  60  20  80
Kellogg        31  38  32  38  29  37 /  20  10  70  60  20  70
Moses Lake     32  38  29  38  34  41 /  10  30  20  10  60  50
Wenatchee      34  37  30  37  33  40 /  50  30  30  10  60  50
Omak           29  34  28  34  32  37 /  70  40  40  10  70  60

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KPQR 170511
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
912 PM PST TUE DEC 16 2014

.SYNOPSIS...A CLOSED LOW JUST OFFSHORE WEST OF THE OR/CA BORDER WILL
SLOWLY WEAKEN AND PUSH NORTHWARD OVERNIGHT...EVENTUALLY MOVING
ONSHORE ALONG THE N OR/S WA COAST TOMORROW AFTERNOON. THIS WILL
MAINTAIN LIGHT SHOWER ACTIVITY...MAINLY OVER THE HIGHER TERRAIN
OVERNIGHT AND TOMORROW MORNING. AN UPPER LEVEL SHORTWAVE WILL PUSH
ONSHORE LATER TOMORROW...LIKELY BRINGING A PERIOD OF STEADIER
RAINFALL THROUGH EARLY THU MORNING. EXPECT A FAIRLY QUIET PERIOD FOR
MUCH OF THE DAY THU...BUT THEN A MORE ORGANIZED FRONT WILL BRING
GUSTY WINDS AND LARGE SURF TO THE COAST...WITH RAIN SPREADING INLAND
THURSDAY NIGHT AND FRIDAY. RISING SNOW LEVELS WILL LIMIT SNOW TO THE
HIGHEST PEAKS...BUT COLDER AIR BEHIND THE FRONT MAY RESULT IN SOME
SNOW SHOWERS FOR THE CASCADES PASSES FRIDAY EVENING AND SATURDAY.
WARMER AND MOISTER WEATHER IS EXPECTED THIS WEEKEND. THERE IS THE
POTENTIAL FOR AN ATMOSPHERIC RIVER TYPE SET UP AND ASSOCIATED HEAVY
RAIN TO DEVELOP OVER THE WEEKEND INTO EARLY NEXT WEEK.

&&

.EVENING UPDATE...A LOW PRES CIRCULATION IS APPARENT ON SATELLITE AND
RADAR IMAGERY THIS EVENING JUST OFFSHORE OF THE CA/OR BORDER. WATER
VAPOR SATELLITE SHOWS MOISTURE SPREADING NORTHWARD FROM THIS SYSTEM
INTO NW OREGON AND SW WASHINGTON. THERE ARE ALSO LIGHT ECHOES SHOWING
UP ON RADAR OVER THE SOUTHERN AND WESTERN PORTIONS OF OUR FCST
AREA...BUT LITTLE TO NO RAIN IS REACHING THE GROUND AT THIS TIME.
EXPECT AS THE NIGHT GOES ON AND THE OFFSHORE LOW SLOWLY MOVES
NORTHEAST...WE WILL SEE LIGHT PRECIPITATION START TO REACH THE
SURFACE...ESPECIALLY OVER THE HIGHER TERRAIN. A WEAK VORT MAX WILL
ALSO MOVE ONSHORE EARLY WED MORNING...WHICH MAY HELP AID THE SHOWERS.

THE MAIN CHANGE TO THE FCST THIS EVENING WAS TO INCREASE POPS AND QPF
FROM THE 18Z WED TO 12Z THU TIME FRAME. THE CLOSED LOW JUST OFFSHORE
TONIGHT WILL SLOWLY WEAKEN AND PUSH ONSHORE AROUND MIDDAY TOMORROW.
MEANWHILE...THE SHORTWAVE NOW APPARENT ON WATER VAPOR SATELLITE
NEARING 45N 140W IS MODELED TO STRETCH OUT AND PUSH ONSHORE LATER
TOMORROW AFTERNOON AND EVENING. THE LOWER LEVEL MOISTURE ASSOCIATED
WITH THE SURFACE LOW COMBINED WITH THE UPPER LEVEL FORCING FROM THE
SHORTWAVE SHOULD DRIVE A PERIOD OF STEADIER PRECIP LATER TOMORROW
AND TOMORROW NIGHT. THE 00Z NAM AND GFS RUNS PICKED UP ON THIS
PERIOD OF ENHANCED PRECIP. THE VORT MAX PUSHES EAST OF THE CASCADES
BY 12Z THU...AFTER WHICH SHOWER ACTIVITY SHOULD DROP OFF
SIGNIFICANTLY. PYLE

.PREV DISC ISSUED 231 PM PST TUE DEC 17...

.SHORT TERM...TONIGHT THROUGH FRIDAY...SHOWERS HAVE PRETTY MUCH ENDED
OVER THE PORTLAND FORECAST AREA EARLY THIS AFTERNOON...EXCEPT FOR
VERY INFREQUENT ISOLATED SHOWER OVER THE SW WASHINGTON CASCADES.
SATELLITE IMAGERY SHOWS A SURFACE LOW AROUND 150 MILES WEST OF THE
SOUTHERN OREGON COAST...NEAR 42N 127W. THE HIGHER RESOLUTION
MODELS...HRRR AND RAP INITIALIZE BEST WITH THE LOW AND FORECAST RAIN
MOVING NORTH INTO LANE COUNTY SLIGHTLY EARLIER THAN THE OTHER MODELS.
HAVE TRENDED TOWARDS THIS EARLIER ARRIVAL...BUT ONLY HAVE FAIR
CONFIDENCE THAT THE TIMING WILL PAN OUT. ANY RAIN LATE THIS AFTERNOON
SHOULD BE FAIRLY LIGHT AND REMAIN WEST OF THE SOUTH AND CENTRAL
WILLAMETTE VALLEY.

THE LOW WILL MOVE CLOSER TO THE SOUTHERN OREGON COAST LATE THIS
AFTERNOON AND EVENING THEN MOVE ONTO THE CENTRAL OREGON COAST AS AN
UPPER TROUGH LATE TONIGHT...WITH SHOWERS MAINLY OVER THE HIGHER
TERRAIN THROUGH WEDNESDAY MORNING. SOME CLEARING EARLY WED MORNING
MAY RESULT IN SHALLOW FOG AND LOW CLOUDS IN SOME OF THE INTERIOR
VALLEYS...MAINLY SOUTH OF SALEM.

EASTERLY WINDS HAVE HELD ON TODAY WITH A TROUTDALE TO DALLES PRESSURE
GRADIENT HOLDING AROUND 5 MB. THIS GRADIENT SHOULD TIGHTEN A LITTLE
THIS EVENING AS THE LOW MOVES CLOSER TO THE COAST AND MAINTAIN GUSTS
AROUND 30 MPH THROUGH THE WESTERN COLUMBIA RIVER GORGE.

SHOWERS WILL CONTINUE WEDNESDAY...MAINLY FOR THE HIGHER TERRAIN AS
THE PARENT UPPER LEVEL TROUGH MOVES OVER THE PACIFIC NW. SHOWERS
SHOULD END OVERNIGHT AS AN UPPER RIDGE BUILDS OVER THE AREA AND
EXPECT THAT CLEARING SKIES AND LIGHT WINDS WILL LEAD TO SHALLOW FOG
FOR THE INTERIOR VALLEYS EARLY THURSDAY MORNING. MOST OF THURSDAY
WILL BE DRY WITH AN INCREASE OF MID AN HIGH LEVEL CLOUDS IN THE
AFTERNOON.

MODELS ARE IN GOOD AGREEMENT THAT A WELL ORGANIZED FRONT WILL BRING
GUSTY WINDS TO THE COAST THURSDAY EVENING WITH RAIN SPREADING INLAND
THURSDAY NIGHT AND FRIDAY. PRECIPITABLE WATER IS EXPECTED TO BE NEAR
AN INCH AND AN APPROACHING JET STREAK SHOULD PROVIDE GOOD LIFT AND
EXPECT THE HIGHEST RAINFALL TOTALS OF 0.75 TO 1 INCH ACROSS THE
COAST AND COAST RANGE THURSDAY NIGHT THROUGH FRIDAY MORNING. OTHER
AREAS SHOULD SEE BETWEEN 0.4 AND 0.60 INCH OF RAIN. SNOW LEVELS
SHOULD REMAIN ABOVE 5000 FEET DURING THE PEAK RAIN PERIOD...BUT LOWER
TO NEAR OR BELOW THE CASCADE PASSES BEHIND THE FRONT FRIDAY
AFTERNOON.

.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY...A BROAD RIDGE OF HIGH
PRESSURE OVER THE WESTERN U.S. FLATTENS AS A STRONG LOW PRESSURE
SYSTEM OVER THE GULF OF ALASKA MOVES INLAND TO OUR NORTH. AS THIS
TROUGH MOVES ON SHORE SATURDAY...THE ASSOCIATED COLD FRONT MOVES
ONSHORE AND STALLS EAST-TO-WEST ACROSS NORTHWEST OREGON AND
SOUTHWEST WASHINGTON. THIS PUTS OUR AREA IN THE PATH OF RAIN
STARTING SATURDAY THROUGH MONDAY. SOME UNCERTAINTY EXISTS IN WHERE
THIS BOUNDARY WILL SET UP...WHICH WILL DETERMINE HOW MUCH RAINFALL
WE WILL GET. ON TUESDAY...GEFS ENSEMBLE SPAGHETTI PLOTS GET MESSY
AND SIGNIFICANT DIFFERENCES START TO SHOW UP BETWEEN THE GFS AND
ECMWF...DECREASING CONFIDENCE ON HOW THE REST OF THE WEEK WILL SHAPE
UP.  AS OF NOW...THE MOST COMMON SOLUTION IS THAT HIGH PRESSURE
RIDGING WILL START TO BUILD BACK OVER THE WESTERN U.S. WHICH
SUGGESTS DRIER WEATHER STARTING TUESDAY...THOUGH UNCERTAINTY IS VERY
HIGH. -MCCOY

&&

.AVIATION...MOIST SOUTHERLY FLOW ALOFT...WITH PLENTY OF MID AND
HIGH CLOUDS OVER REGION. DO HAVE AREAS OF MVFR CIGS ALONG THE
COAST AND WILL SEE THOSE PERSIST OVERNIGHT INTO WED AM. QUESTION
IS WHETHER OR NOT LOW CLOUDS REFORM S OF SALEM TONIGHT. HAVE
CLEARED OUT AT MOMENT...WITH STILL RATHER HIGH HUMIDITY. SO
SUSPECT WITH OCCASIONAL LIGHT RAIN THERE...WILL SEE AREAS OF IFR
STRATUS REFORM TONIGHT TO SOUTH OF KSLE.

KPDX AND APPROACHES...VFR WILL PERSIST TONIGHT AND WED...BUT CIGS
LOWER TO 5K FT LATER AFTER 09Z WITH OCCASIONAL LIGHT RAIN THROUGH
17Z. VFR WITH LOT OF MID AND HIGH CLOUDS ON WED.ROCKEY.
 &&

.MARINE...NOT MUCH CHANGE. GRADIENTS WEAKENING THIS EVENING AS
LOW HEADS INTO N CALIF. STILL...WILL GET A GUSTS TO 25 KT ON THE
OUTER SOUTH WATERS THIS EVENING. SEAS HOLDING AT 8 TO 9 FT.

NEXT SYSTEM NOW DEVELOPING WAY OFFSHORE BETWEEN 160W-170W. THIS
SYSTEM WILL BRING SOUTHERLY GALES TO THE WATERS LATER THU THROUGH
EARLY FRI AM. STILL SOME UNCERTAINTY ON EXACT TIMING AND DETAILS
BUT WILL BE VERY ACTIVE PERIOD. SEAS LIKELY TO PUSH BACK INTO THE
UPPER TEENS TO NEAR 20 FT BY FRI AM.

MORE FRONTS ARRIVE THIS WEEKEND INTO EARLY NEXT WEEK...WITH
SOUTHERLY GALES LIKELY AND ENHANCED SEAS.   ROCKEY.
&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...GALE WATCH FOR THU AND THU NIGHT ON ALL COASTAL WATERS.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR TONIGHT
AND AGAIN 11 AM TO 4 PM WED.

&&


$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.




000
FXUS66 KPQR 170511
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
912 PM PST TUE DEC 16 2014

.SYNOPSIS...A CLOSED LOW JUST OFFSHORE WEST OF THE OR/CA BORDER WILL
SLOWLY WEAKEN AND PUSH NORTHWARD OVERNIGHT...EVENTUALLY MOVING
ONSHORE ALONG THE N OR/S WA COAST TOMORROW AFTERNOON. THIS WILL
MAINTAIN LIGHT SHOWER ACTIVITY...MAINLY OVER THE HIGHER TERRAIN
OVERNIGHT AND TOMORROW MORNING. AN UPPER LEVEL SHORTWAVE WILL PUSH
ONSHORE LATER TOMORROW...LIKELY BRINGING A PERIOD OF STEADIER
RAINFALL THROUGH EARLY THU MORNING. EXPECT A FAIRLY QUIET PERIOD FOR
MUCH OF THE DAY THU...BUT THEN A MORE ORGANIZED FRONT WILL BRING
GUSTY WINDS AND LARGE SURF TO THE COAST...WITH RAIN SPREADING INLAND
THURSDAY NIGHT AND FRIDAY. RISING SNOW LEVELS WILL LIMIT SNOW TO THE
HIGHEST PEAKS...BUT COLDER AIR BEHIND THE FRONT MAY RESULT IN SOME
SNOW SHOWERS FOR THE CASCADES PASSES FRIDAY EVENING AND SATURDAY.
WARMER AND MOISTER WEATHER IS EXPECTED THIS WEEKEND. THERE IS THE
POTENTIAL FOR AN ATMOSPHERIC RIVER TYPE SET UP AND ASSOCIATED HEAVY
RAIN TO DEVELOP OVER THE WEEKEND INTO EARLY NEXT WEEK.

&&

.EVENING UPDATE...A LOW PRES CIRCULATION IS APPARENT ON SATELLITE AND
RADAR IMAGERY THIS EVENING JUST OFFSHORE OF THE CA/OR BORDER. WATER
VAPOR SATELLITE SHOWS MOISTURE SPREADING NORTHWARD FROM THIS SYSTEM
INTO NW OREGON AND SW WASHINGTON. THERE ARE ALSO LIGHT ECHOES SHOWING
UP ON RADAR OVER THE SOUTHERN AND WESTERN PORTIONS OF OUR FCST
AREA...BUT LITTLE TO NO RAIN IS REACHING THE GROUND AT THIS TIME.
EXPECT AS THE NIGHT GOES ON AND THE OFFSHORE LOW SLOWLY MOVES
NORTHEAST...WE WILL SEE LIGHT PRECIPITATION START TO REACH THE
SURFACE...ESPECIALLY OVER THE HIGHER TERRAIN. A WEAK VORT MAX WILL
ALSO MOVE ONSHORE EARLY WED MORNING...WHICH MAY HELP AID THE SHOWERS.

THE MAIN CHANGE TO THE FCST THIS EVENING WAS TO INCREASE POPS AND QPF
FROM THE 18Z WED TO 12Z THU TIME FRAME. THE CLOSED LOW JUST OFFSHORE
TONIGHT WILL SLOWLY WEAKEN AND PUSH ONSHORE AROUND MIDDAY TOMORROW.
MEANWHILE...THE SHORTWAVE NOW APPARENT ON WATER VAPOR SATELLITE
NEARING 45N 140W IS MODELED TO STRETCH OUT AND PUSH ONSHORE LATER
TOMORROW AFTERNOON AND EVENING. THE LOWER LEVEL MOISTURE ASSOCIATED
WITH THE SURFACE LOW COMBINED WITH THE UPPER LEVEL FORCING FROM THE
SHORTWAVE SHOULD DRIVE A PERIOD OF STEADIER PRECIP LATER TOMORROW
AND TOMORROW NIGHT. THE 00Z NAM AND GFS RUNS PICKED UP ON THIS
PERIOD OF ENHANCED PRECIP. THE VORT MAX PUSHES EAST OF THE CASCADES
BY 12Z THU...AFTER WHICH SHOWER ACTIVITY SHOULD DROP OFF
SIGNIFICANTLY. PYLE

.PREV DISC ISSUED 231 PM PST TUE DEC 17...

.SHORT TERM...TONIGHT THROUGH FRIDAY...SHOWERS HAVE PRETTY MUCH ENDED
OVER THE PORTLAND FORECAST AREA EARLY THIS AFTERNOON...EXCEPT FOR
VERY INFREQUENT ISOLATED SHOWER OVER THE SW WASHINGTON CASCADES.
SATELLITE IMAGERY SHOWS A SURFACE LOW AROUND 150 MILES WEST OF THE
SOUTHERN OREGON COAST...NEAR 42N 127W. THE HIGHER RESOLUTION
MODELS...HRRR AND RAP INITIALIZE BEST WITH THE LOW AND FORECAST RAIN
MOVING NORTH INTO LANE COUNTY SLIGHTLY EARLIER THAN THE OTHER MODELS.
HAVE TRENDED TOWARDS THIS EARLIER ARRIVAL...BUT ONLY HAVE FAIR
CONFIDENCE THAT THE TIMING WILL PAN OUT. ANY RAIN LATE THIS AFTERNOON
SHOULD BE FAIRLY LIGHT AND REMAIN WEST OF THE SOUTH AND CENTRAL
WILLAMETTE VALLEY.

THE LOW WILL MOVE CLOSER TO THE SOUTHERN OREGON COAST LATE THIS
AFTERNOON AND EVENING THEN MOVE ONTO THE CENTRAL OREGON COAST AS AN
UPPER TROUGH LATE TONIGHT...WITH SHOWERS MAINLY OVER THE HIGHER
TERRAIN THROUGH WEDNESDAY MORNING. SOME CLEARING EARLY WED MORNING
MAY RESULT IN SHALLOW FOG AND LOW CLOUDS IN SOME OF THE INTERIOR
VALLEYS...MAINLY SOUTH OF SALEM.

EASTERLY WINDS HAVE HELD ON TODAY WITH A TROUTDALE TO DALLES PRESSURE
GRADIENT HOLDING AROUND 5 MB. THIS GRADIENT SHOULD TIGHTEN A LITTLE
THIS EVENING AS THE LOW MOVES CLOSER TO THE COAST AND MAINTAIN GUSTS
AROUND 30 MPH THROUGH THE WESTERN COLUMBIA RIVER GORGE.

SHOWERS WILL CONTINUE WEDNESDAY...MAINLY FOR THE HIGHER TERRAIN AS
THE PARENT UPPER LEVEL TROUGH MOVES OVER THE PACIFIC NW. SHOWERS
SHOULD END OVERNIGHT AS AN UPPER RIDGE BUILDS OVER THE AREA AND
EXPECT THAT CLEARING SKIES AND LIGHT WINDS WILL LEAD TO SHALLOW FOG
FOR THE INTERIOR VALLEYS EARLY THURSDAY MORNING. MOST OF THURSDAY
WILL BE DRY WITH AN INCREASE OF MID AN HIGH LEVEL CLOUDS IN THE
AFTERNOON.

MODELS ARE IN GOOD AGREEMENT THAT A WELL ORGANIZED FRONT WILL BRING
GUSTY WINDS TO THE COAST THURSDAY EVENING WITH RAIN SPREADING INLAND
THURSDAY NIGHT AND FRIDAY. PRECIPITABLE WATER IS EXPECTED TO BE NEAR
AN INCH AND AN APPROACHING JET STREAK SHOULD PROVIDE GOOD LIFT AND
EXPECT THE HIGHEST RAINFALL TOTALS OF 0.75 TO 1 INCH ACROSS THE
COAST AND COAST RANGE THURSDAY NIGHT THROUGH FRIDAY MORNING. OTHER
AREAS SHOULD SEE BETWEEN 0.4 AND 0.60 INCH OF RAIN. SNOW LEVELS
SHOULD REMAIN ABOVE 5000 FEET DURING THE PEAK RAIN PERIOD...BUT LOWER
TO NEAR OR BELOW THE CASCADE PASSES BEHIND THE FRONT FRIDAY
AFTERNOON.

.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY...A BROAD RIDGE OF HIGH
PRESSURE OVER THE WESTERN U.S. FLATTENS AS A STRONG LOW PRESSURE
SYSTEM OVER THE GULF OF ALASKA MOVES INLAND TO OUR NORTH. AS THIS
TROUGH MOVES ON SHORE SATURDAY...THE ASSOCIATED COLD FRONT MOVES
ONSHORE AND STALLS EAST-TO-WEST ACROSS NORTHWEST OREGON AND
SOUTHWEST WASHINGTON. THIS PUTS OUR AREA IN THE PATH OF RAIN
STARTING SATURDAY THROUGH MONDAY. SOME UNCERTAINTY EXISTS IN WHERE
THIS BOUNDARY WILL SET UP...WHICH WILL DETERMINE HOW MUCH RAINFALL
WE WILL GET. ON TUESDAY...GEFS ENSEMBLE SPAGHETTI PLOTS GET MESSY
AND SIGNIFICANT DIFFERENCES START TO SHOW UP BETWEEN THE GFS AND
ECMWF...DECREASING CONFIDENCE ON HOW THE REST OF THE WEEK WILL SHAPE
UP.  AS OF NOW...THE MOST COMMON SOLUTION IS THAT HIGH PRESSURE
RIDGING WILL START TO BUILD BACK OVER THE WESTERN U.S. WHICH
SUGGESTS DRIER WEATHER STARTING TUESDAY...THOUGH UNCERTAINTY IS VERY
HIGH. -MCCOY

&&

.AVIATION...MOIST SOUTHERLY FLOW ALOFT...WITH PLENTY OF MID AND
HIGH CLOUDS OVER REGION. DO HAVE AREAS OF MVFR CIGS ALONG THE
COAST AND WILL SEE THOSE PERSIST OVERNIGHT INTO WED AM. QUESTION
IS WHETHER OR NOT LOW CLOUDS REFORM S OF SALEM TONIGHT. HAVE
CLEARED OUT AT MOMENT...WITH STILL RATHER HIGH HUMIDITY. SO
SUSPECT WITH OCCASIONAL LIGHT RAIN THERE...WILL SEE AREAS OF IFR
STRATUS REFORM TONIGHT TO SOUTH OF KSLE.

KPDX AND APPROACHES...VFR WILL PERSIST TONIGHT AND WED...BUT CIGS
LOWER TO 5K FT LATER AFTER 09Z WITH OCCASIONAL LIGHT RAIN THROUGH
17Z. VFR WITH LOT OF MID AND HIGH CLOUDS ON WED.ROCKEY.
 &&

.MARINE...NOT MUCH CHANGE. GRADIENTS WEAKENING THIS EVENING AS
LOW HEADS INTO N CALIF. STILL...WILL GET A GUSTS TO 25 KT ON THE
OUTER SOUTH WATERS THIS EVENING. SEAS HOLDING AT 8 TO 9 FT.

NEXT SYSTEM NOW DEVELOPING WAY OFFSHORE BETWEEN 160W-170W. THIS
SYSTEM WILL BRING SOUTHERLY GALES TO THE WATERS LATER THU THROUGH
EARLY FRI AM. STILL SOME UNCERTAINTY ON EXACT TIMING AND DETAILS
BUT WILL BE VERY ACTIVE PERIOD. SEAS LIKELY TO PUSH BACK INTO THE
UPPER TEENS TO NEAR 20 FT BY FRI AM.

MORE FRONTS ARRIVE THIS WEEKEND INTO EARLY NEXT WEEK...WITH
SOUTHERLY GALES LIKELY AND ENHANCED SEAS.   ROCKEY.
&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...GALE WATCH FOR THU AND THU NIGHT ON ALL COASTAL WATERS.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR TONIGHT
AND AGAIN 11 AM TO 4 PM WED.

&&


$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.




000
FXUS66 KPQR 170511
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
912 PM PST TUE DEC 16 2014

.SYNOPSIS...A CLOSED LOW JUST OFFSHORE WEST OF THE OR/CA BORDER WILL
SLOWLY WEAKEN AND PUSH NORTHWARD OVERNIGHT...EVENTUALLY MOVING
ONSHORE ALONG THE N OR/S WA COAST TOMORROW AFTERNOON. THIS WILL
MAINTAIN LIGHT SHOWER ACTIVITY...MAINLY OVER THE HIGHER TERRAIN
OVERNIGHT AND TOMORROW MORNING. AN UPPER LEVEL SHORTWAVE WILL PUSH
ONSHORE LATER TOMORROW...LIKELY BRINGING A PERIOD OF STEADIER
RAINFALL THROUGH EARLY THU MORNING. EXPECT A FAIRLY QUIET PERIOD FOR
MUCH OF THE DAY THU...BUT THEN A MORE ORGANIZED FRONT WILL BRING
GUSTY WINDS AND LARGE SURF TO THE COAST...WITH RAIN SPREADING INLAND
THURSDAY NIGHT AND FRIDAY. RISING SNOW LEVELS WILL LIMIT SNOW TO THE
HIGHEST PEAKS...BUT COLDER AIR BEHIND THE FRONT MAY RESULT IN SOME
SNOW SHOWERS FOR THE CASCADES PASSES FRIDAY EVENING AND SATURDAY.
WARMER AND MOISTER WEATHER IS EXPECTED THIS WEEKEND. THERE IS THE
POTENTIAL FOR AN ATMOSPHERIC RIVER TYPE SET UP AND ASSOCIATED HEAVY
RAIN TO DEVELOP OVER THE WEEKEND INTO EARLY NEXT WEEK.

&&

.EVENING UPDATE...A LOW PRES CIRCULATION IS APPARENT ON SATELLITE AND
RADAR IMAGERY THIS EVENING JUST OFFSHORE OF THE CA/OR BORDER. WATER
VAPOR SATELLITE SHOWS MOISTURE SPREADING NORTHWARD FROM THIS SYSTEM
INTO NW OREGON AND SW WASHINGTON. THERE ARE ALSO LIGHT ECHOES SHOWING
UP ON RADAR OVER THE SOUTHERN AND WESTERN PORTIONS OF OUR FCST
AREA...BUT LITTLE TO NO RAIN IS REACHING THE GROUND AT THIS TIME.
EXPECT AS THE NIGHT GOES ON AND THE OFFSHORE LOW SLOWLY MOVES
NORTHEAST...WE WILL SEE LIGHT PRECIPITATION START TO REACH THE
SURFACE...ESPECIALLY OVER THE HIGHER TERRAIN. A WEAK VORT MAX WILL
ALSO MOVE ONSHORE EARLY WED MORNING...WHICH MAY HELP AID THE SHOWERS.

THE MAIN CHANGE TO THE FCST THIS EVENING WAS TO INCREASE POPS AND QPF
FROM THE 18Z WED TO 12Z THU TIME FRAME. THE CLOSED LOW JUST OFFSHORE
TONIGHT WILL SLOWLY WEAKEN AND PUSH ONSHORE AROUND MIDDAY TOMORROW.
MEANWHILE...THE SHORTWAVE NOW APPARENT ON WATER VAPOR SATELLITE
NEARING 45N 140W IS MODELED TO STRETCH OUT AND PUSH ONSHORE LATER
TOMORROW AFTERNOON AND EVENING. THE LOWER LEVEL MOISTURE ASSOCIATED
WITH THE SURFACE LOW COMBINED WITH THE UPPER LEVEL FORCING FROM THE
SHORTWAVE SHOULD DRIVE A PERIOD OF STEADIER PRECIP LATER TOMORROW
AND TOMORROW NIGHT. THE 00Z NAM AND GFS RUNS PICKED UP ON THIS
PERIOD OF ENHANCED PRECIP. THE VORT MAX PUSHES EAST OF THE CASCADES
BY 12Z THU...AFTER WHICH SHOWER ACTIVITY SHOULD DROP OFF
SIGNIFICANTLY. PYLE

.PREV DISC ISSUED 231 PM PST TUE DEC 17...

.SHORT TERM...TONIGHT THROUGH FRIDAY...SHOWERS HAVE PRETTY MUCH ENDED
OVER THE PORTLAND FORECAST AREA EARLY THIS AFTERNOON...EXCEPT FOR
VERY INFREQUENT ISOLATED SHOWER OVER THE SW WASHINGTON CASCADES.
SATELLITE IMAGERY SHOWS A SURFACE LOW AROUND 150 MILES WEST OF THE
SOUTHERN OREGON COAST...NEAR 42N 127W. THE HIGHER RESOLUTION
MODELS...HRRR AND RAP INITIALIZE BEST WITH THE LOW AND FORECAST RAIN
MOVING NORTH INTO LANE COUNTY SLIGHTLY EARLIER THAN THE OTHER MODELS.
HAVE TRENDED TOWARDS THIS EARLIER ARRIVAL...BUT ONLY HAVE FAIR
CONFIDENCE THAT THE TIMING WILL PAN OUT. ANY RAIN LATE THIS AFTERNOON
SHOULD BE FAIRLY LIGHT AND REMAIN WEST OF THE SOUTH AND CENTRAL
WILLAMETTE VALLEY.

THE LOW WILL MOVE CLOSER TO THE SOUTHERN OREGON COAST LATE THIS
AFTERNOON AND EVENING THEN MOVE ONTO THE CENTRAL OREGON COAST AS AN
UPPER TROUGH LATE TONIGHT...WITH SHOWERS MAINLY OVER THE HIGHER
TERRAIN THROUGH WEDNESDAY MORNING. SOME CLEARING EARLY WED MORNING
MAY RESULT IN SHALLOW FOG AND LOW CLOUDS IN SOME OF THE INTERIOR
VALLEYS...MAINLY SOUTH OF SALEM.

EASTERLY WINDS HAVE HELD ON TODAY WITH A TROUTDALE TO DALLES PRESSURE
GRADIENT HOLDING AROUND 5 MB. THIS GRADIENT SHOULD TIGHTEN A LITTLE
THIS EVENING AS THE LOW MOVES CLOSER TO THE COAST AND MAINTAIN GUSTS
AROUND 30 MPH THROUGH THE WESTERN COLUMBIA RIVER GORGE.

SHOWERS WILL CONTINUE WEDNESDAY...MAINLY FOR THE HIGHER TERRAIN AS
THE PARENT UPPER LEVEL TROUGH MOVES OVER THE PACIFIC NW. SHOWERS
SHOULD END OVERNIGHT AS AN UPPER RIDGE BUILDS OVER THE AREA AND
EXPECT THAT CLEARING SKIES AND LIGHT WINDS WILL LEAD TO SHALLOW FOG
FOR THE INTERIOR VALLEYS EARLY THURSDAY MORNING. MOST OF THURSDAY
WILL BE DRY WITH AN INCREASE OF MID AN HIGH LEVEL CLOUDS IN THE
AFTERNOON.

MODELS ARE IN GOOD AGREEMENT THAT A WELL ORGANIZED FRONT WILL BRING
GUSTY WINDS TO THE COAST THURSDAY EVENING WITH RAIN SPREADING INLAND
THURSDAY NIGHT AND FRIDAY. PRECIPITABLE WATER IS EXPECTED TO BE NEAR
AN INCH AND AN APPROACHING JET STREAK SHOULD PROVIDE GOOD LIFT AND
EXPECT THE HIGHEST RAINFALL TOTALS OF 0.75 TO 1 INCH ACROSS THE
COAST AND COAST RANGE THURSDAY NIGHT THROUGH FRIDAY MORNING. OTHER
AREAS SHOULD SEE BETWEEN 0.4 AND 0.60 INCH OF RAIN. SNOW LEVELS
SHOULD REMAIN ABOVE 5000 FEET DURING THE PEAK RAIN PERIOD...BUT LOWER
TO NEAR OR BELOW THE CASCADE PASSES BEHIND THE FRONT FRIDAY
AFTERNOON.

.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY...A BROAD RIDGE OF HIGH
PRESSURE OVER THE WESTERN U.S. FLATTENS AS A STRONG LOW PRESSURE
SYSTEM OVER THE GULF OF ALASKA MOVES INLAND TO OUR NORTH. AS THIS
TROUGH MOVES ON SHORE SATURDAY...THE ASSOCIATED COLD FRONT MOVES
ONSHORE AND STALLS EAST-TO-WEST ACROSS NORTHWEST OREGON AND
SOUTHWEST WASHINGTON. THIS PUTS OUR AREA IN THE PATH OF RAIN
STARTING SATURDAY THROUGH MONDAY. SOME UNCERTAINTY EXISTS IN WHERE
THIS BOUNDARY WILL SET UP...WHICH WILL DETERMINE HOW MUCH RAINFALL
WE WILL GET. ON TUESDAY...GEFS ENSEMBLE SPAGHETTI PLOTS GET MESSY
AND SIGNIFICANT DIFFERENCES START TO SHOW UP BETWEEN THE GFS AND
ECMWF...DECREASING CONFIDENCE ON HOW THE REST OF THE WEEK WILL SHAPE
UP.  AS OF NOW...THE MOST COMMON SOLUTION IS THAT HIGH PRESSURE
RIDGING WILL START TO BUILD BACK OVER THE WESTERN U.S. WHICH
SUGGESTS DRIER WEATHER STARTING TUESDAY...THOUGH UNCERTAINTY IS VERY
HIGH. -MCCOY

&&

.AVIATION...MOIST SOUTHERLY FLOW ALOFT...WITH PLENTY OF MID AND
HIGH CLOUDS OVER REGION. DO HAVE AREAS OF MVFR CIGS ALONG THE
COAST AND WILL SEE THOSE PERSIST OVERNIGHT INTO WED AM. QUESTION
IS WHETHER OR NOT LOW CLOUDS REFORM S OF SALEM TONIGHT. HAVE
CLEARED OUT AT MOMENT...WITH STILL RATHER HIGH HUMIDITY. SO
SUSPECT WITH OCCASIONAL LIGHT RAIN THERE...WILL SEE AREAS OF IFR
STRATUS REFORM TONIGHT TO SOUTH OF KSLE.

KPDX AND APPROACHES...VFR WILL PERSIST TONIGHT AND WED...BUT CIGS
LOWER TO 5K FT LATER AFTER 09Z WITH OCCASIONAL LIGHT RAIN THROUGH
17Z. VFR WITH LOT OF MID AND HIGH CLOUDS ON WED.ROCKEY.
 &&

.MARINE...NOT MUCH CHANGE. GRADIENTS WEAKENING THIS EVENING AS
LOW HEADS INTO N CALIF. STILL...WILL GET A GUSTS TO 25 KT ON THE
OUTER SOUTH WATERS THIS EVENING. SEAS HOLDING AT 8 TO 9 FT.

NEXT SYSTEM NOW DEVELOPING WAY OFFSHORE BETWEEN 160W-170W. THIS
SYSTEM WILL BRING SOUTHERLY GALES TO THE WATERS LATER THU THROUGH
EARLY FRI AM. STILL SOME UNCERTAINTY ON EXACT TIMING AND DETAILS
BUT WILL BE VERY ACTIVE PERIOD. SEAS LIKELY TO PUSH BACK INTO THE
UPPER TEENS TO NEAR 20 FT BY FRI AM.

MORE FRONTS ARRIVE THIS WEEKEND INTO EARLY NEXT WEEK...WITH
SOUTHERLY GALES LIKELY AND ENHANCED SEAS.   ROCKEY.
&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...GALE WATCH FOR THU AND THU NIGHT ON ALL COASTAL WATERS.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR TONIGHT
AND AGAIN 11 AM TO 4 PM WED.

&&


$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.




000
FXUS66 KPQR 170511
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
912 PM PST TUE DEC 16 2014

.SYNOPSIS...A CLOSED LOW JUST OFFSHORE WEST OF THE OR/CA BORDER WILL
SLOWLY WEAKEN AND PUSH NORTHWARD OVERNIGHT...EVENTUALLY MOVING
ONSHORE ALONG THE N OR/S WA COAST TOMORROW AFTERNOON. THIS WILL
MAINTAIN LIGHT SHOWER ACTIVITY...MAINLY OVER THE HIGHER TERRAIN
OVERNIGHT AND TOMORROW MORNING. AN UPPER LEVEL SHORTWAVE WILL PUSH
ONSHORE LATER TOMORROW...LIKELY BRINGING A PERIOD OF STEADIER
RAINFALL THROUGH EARLY THU MORNING. EXPECT A FAIRLY QUIET PERIOD FOR
MUCH OF THE DAY THU...BUT THEN A MORE ORGANIZED FRONT WILL BRING
GUSTY WINDS AND LARGE SURF TO THE COAST...WITH RAIN SPREADING INLAND
THURSDAY NIGHT AND FRIDAY. RISING SNOW LEVELS WILL LIMIT SNOW TO THE
HIGHEST PEAKS...BUT COLDER AIR BEHIND THE FRONT MAY RESULT IN SOME
SNOW SHOWERS FOR THE CASCADES PASSES FRIDAY EVENING AND SATURDAY.
WARMER AND MOISTER WEATHER IS EXPECTED THIS WEEKEND. THERE IS THE
POTENTIAL FOR AN ATMOSPHERIC RIVER TYPE SET UP AND ASSOCIATED HEAVY
RAIN TO DEVELOP OVER THE WEEKEND INTO EARLY NEXT WEEK.

&&

.EVENING UPDATE...A LOW PRES CIRCULATION IS APPARENT ON SATELLITE AND
RADAR IMAGERY THIS EVENING JUST OFFSHORE OF THE CA/OR BORDER. WATER
VAPOR SATELLITE SHOWS MOISTURE SPREADING NORTHWARD FROM THIS SYSTEM
INTO NW OREGON AND SW WASHINGTON. THERE ARE ALSO LIGHT ECHOES SHOWING
UP ON RADAR OVER THE SOUTHERN AND WESTERN PORTIONS OF OUR FCST
AREA...BUT LITTLE TO NO RAIN IS REACHING THE GROUND AT THIS TIME.
EXPECT AS THE NIGHT GOES ON AND THE OFFSHORE LOW SLOWLY MOVES
NORTHEAST...WE WILL SEE LIGHT PRECIPITATION START TO REACH THE
SURFACE...ESPECIALLY OVER THE HIGHER TERRAIN. A WEAK VORT MAX WILL
ALSO MOVE ONSHORE EARLY WED MORNING...WHICH MAY HELP AID THE SHOWERS.

THE MAIN CHANGE TO THE FCST THIS EVENING WAS TO INCREASE POPS AND QPF
FROM THE 18Z WED TO 12Z THU TIME FRAME. THE CLOSED LOW JUST OFFSHORE
TONIGHT WILL SLOWLY WEAKEN AND PUSH ONSHORE AROUND MIDDAY TOMORROW.
MEANWHILE...THE SHORTWAVE NOW APPARENT ON WATER VAPOR SATELLITE
NEARING 45N 140W IS MODELED TO STRETCH OUT AND PUSH ONSHORE LATER
TOMORROW AFTERNOON AND EVENING. THE LOWER LEVEL MOISTURE ASSOCIATED
WITH THE SURFACE LOW COMBINED WITH THE UPPER LEVEL FORCING FROM THE
SHORTWAVE SHOULD DRIVE A PERIOD OF STEADIER PRECIP LATER TOMORROW
AND TOMORROW NIGHT. THE 00Z NAM AND GFS RUNS PICKED UP ON THIS
PERIOD OF ENHANCED PRECIP. THE VORT MAX PUSHES EAST OF THE CASCADES
BY 12Z THU...AFTER WHICH SHOWER ACTIVITY SHOULD DROP OFF
SIGNIFICANTLY. PYLE

.PREV DISC ISSUED 231 PM PST TUE DEC 17...

.SHORT TERM...TONIGHT THROUGH FRIDAY...SHOWERS HAVE PRETTY MUCH ENDED
OVER THE PORTLAND FORECAST AREA EARLY THIS AFTERNOON...EXCEPT FOR
VERY INFREQUENT ISOLATED SHOWER OVER THE SW WASHINGTON CASCADES.
SATELLITE IMAGERY SHOWS A SURFACE LOW AROUND 150 MILES WEST OF THE
SOUTHERN OREGON COAST...NEAR 42N 127W. THE HIGHER RESOLUTION
MODELS...HRRR AND RAP INITIALIZE BEST WITH THE LOW AND FORECAST RAIN
MOVING NORTH INTO LANE COUNTY SLIGHTLY EARLIER THAN THE OTHER MODELS.
HAVE TRENDED TOWARDS THIS EARLIER ARRIVAL...BUT ONLY HAVE FAIR
CONFIDENCE THAT THE TIMING WILL PAN OUT. ANY RAIN LATE THIS AFTERNOON
SHOULD BE FAIRLY LIGHT AND REMAIN WEST OF THE SOUTH AND CENTRAL
WILLAMETTE VALLEY.

THE LOW WILL MOVE CLOSER TO THE SOUTHERN OREGON COAST LATE THIS
AFTERNOON AND EVENING THEN MOVE ONTO THE CENTRAL OREGON COAST AS AN
UPPER TROUGH LATE TONIGHT...WITH SHOWERS MAINLY OVER THE HIGHER
TERRAIN THROUGH WEDNESDAY MORNING. SOME CLEARING EARLY WED MORNING
MAY RESULT IN SHALLOW FOG AND LOW CLOUDS IN SOME OF THE INTERIOR
VALLEYS...MAINLY SOUTH OF SALEM.

EASTERLY WINDS HAVE HELD ON TODAY WITH A TROUTDALE TO DALLES PRESSURE
GRADIENT HOLDING AROUND 5 MB. THIS GRADIENT SHOULD TIGHTEN A LITTLE
THIS EVENING AS THE LOW MOVES CLOSER TO THE COAST AND MAINTAIN GUSTS
AROUND 30 MPH THROUGH THE WESTERN COLUMBIA RIVER GORGE.

SHOWERS WILL CONTINUE WEDNESDAY...MAINLY FOR THE HIGHER TERRAIN AS
THE PARENT UPPER LEVEL TROUGH MOVES OVER THE PACIFIC NW. SHOWERS
SHOULD END OVERNIGHT AS AN UPPER RIDGE BUILDS OVER THE AREA AND
EXPECT THAT CLEARING SKIES AND LIGHT WINDS WILL LEAD TO SHALLOW FOG
FOR THE INTERIOR VALLEYS EARLY THURSDAY MORNING. MOST OF THURSDAY
WILL BE DRY WITH AN INCREASE OF MID AN HIGH LEVEL CLOUDS IN THE
AFTERNOON.

MODELS ARE IN GOOD AGREEMENT THAT A WELL ORGANIZED FRONT WILL BRING
GUSTY WINDS TO THE COAST THURSDAY EVENING WITH RAIN SPREADING INLAND
THURSDAY NIGHT AND FRIDAY. PRECIPITABLE WATER IS EXPECTED TO BE NEAR
AN INCH AND AN APPROACHING JET STREAK SHOULD PROVIDE GOOD LIFT AND
EXPECT THE HIGHEST RAINFALL TOTALS OF 0.75 TO 1 INCH ACROSS THE
COAST AND COAST RANGE THURSDAY NIGHT THROUGH FRIDAY MORNING. OTHER
AREAS SHOULD SEE BETWEEN 0.4 AND 0.60 INCH OF RAIN. SNOW LEVELS
SHOULD REMAIN ABOVE 5000 FEET DURING THE PEAK RAIN PERIOD...BUT LOWER
TO NEAR OR BELOW THE CASCADE PASSES BEHIND THE FRONT FRIDAY
AFTERNOON.

.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY...A BROAD RIDGE OF HIGH
PRESSURE OVER THE WESTERN U.S. FLATTENS AS A STRONG LOW PRESSURE
SYSTEM OVER THE GULF OF ALASKA MOVES INLAND TO OUR NORTH. AS THIS
TROUGH MOVES ON SHORE SATURDAY...THE ASSOCIATED COLD FRONT MOVES
ONSHORE AND STALLS EAST-TO-WEST ACROSS NORTHWEST OREGON AND
SOUTHWEST WASHINGTON. THIS PUTS OUR AREA IN THE PATH OF RAIN
STARTING SATURDAY THROUGH MONDAY. SOME UNCERTAINTY EXISTS IN WHERE
THIS BOUNDARY WILL SET UP...WHICH WILL DETERMINE HOW MUCH RAINFALL
WE WILL GET. ON TUESDAY...GEFS ENSEMBLE SPAGHETTI PLOTS GET MESSY
AND SIGNIFICANT DIFFERENCES START TO SHOW UP BETWEEN THE GFS AND
ECMWF...DECREASING CONFIDENCE ON HOW THE REST OF THE WEEK WILL SHAPE
UP.  AS OF NOW...THE MOST COMMON SOLUTION IS THAT HIGH PRESSURE
RIDGING WILL START TO BUILD BACK OVER THE WESTERN U.S. WHICH
SUGGESTS DRIER WEATHER STARTING TUESDAY...THOUGH UNCERTAINTY IS VERY
HIGH. -MCCOY

&&

.AVIATION...MOIST SOUTHERLY FLOW ALOFT...WITH PLENTY OF MID AND
HIGH CLOUDS OVER REGION. DO HAVE AREAS OF MVFR CIGS ALONG THE
COAST AND WILL SEE THOSE PERSIST OVERNIGHT INTO WED AM. QUESTION
IS WHETHER OR NOT LOW CLOUDS REFORM S OF SALEM TONIGHT. HAVE
CLEARED OUT AT MOMENT...WITH STILL RATHER HIGH HUMIDITY. SO
SUSPECT WITH OCCASIONAL LIGHT RAIN THERE...WILL SEE AREAS OF IFR
STRATUS REFORM TONIGHT TO SOUTH OF KSLE.

KPDX AND APPROACHES...VFR WILL PERSIST TONIGHT AND WED...BUT CIGS
LOWER TO 5K FT LATER AFTER 09Z WITH OCCASIONAL LIGHT RAIN THROUGH
17Z. VFR WITH LOT OF MID AND HIGH CLOUDS ON WED.ROCKEY.
 &&

.MARINE...NOT MUCH CHANGE. GRADIENTS WEAKENING THIS EVENING AS
LOW HEADS INTO N CALIF. STILL...WILL GET A GUSTS TO 25 KT ON THE
OUTER SOUTH WATERS THIS EVENING. SEAS HOLDING AT 8 TO 9 FT.

NEXT SYSTEM NOW DEVELOPING WAY OFFSHORE BETWEEN 160W-170W. THIS
SYSTEM WILL BRING SOUTHERLY GALES TO THE WATERS LATER THU THROUGH
EARLY FRI AM. STILL SOME UNCERTAINTY ON EXACT TIMING AND DETAILS
BUT WILL BE VERY ACTIVE PERIOD. SEAS LIKELY TO PUSH BACK INTO THE
UPPER TEENS TO NEAR 20 FT BY FRI AM.

MORE FRONTS ARRIVE THIS WEEKEND INTO EARLY NEXT WEEK...WITH
SOUTHERLY GALES LIKELY AND ENHANCED SEAS.   ROCKEY.
&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...GALE WATCH FOR THU AND THU NIGHT ON ALL COASTAL WATERS.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR TONIGHT
AND AGAIN 11 AM TO 4 PM WED.

&&


$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.




000
FXUS66 KPQR 170511
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
912 PM PST TUE DEC 16 2014

.SYNOPSIS...A CLOSED LOW JUST OFFSHORE WEST OF THE OR/CA BORDER WILL
SLOWLY WEAKEN AND PUSH NORTHWARD OVERNIGHT...EVENTUALLY MOVING
ONSHORE ALONG THE N OR/S WA COAST TOMORROW AFTERNOON. THIS WILL
MAINTAIN LIGHT SHOWER ACTIVITY...MAINLY OVER THE HIGHER TERRAIN
OVERNIGHT AND TOMORROW MORNING. AN UPPER LEVEL SHORTWAVE WILL PUSH
ONSHORE LATER TOMORROW...LIKELY BRINGING A PERIOD OF STEADIER
RAINFALL THROUGH EARLY THU MORNING. EXPECT A FAIRLY QUIET PERIOD FOR
MUCH OF THE DAY THU...BUT THEN A MORE ORGANIZED FRONT WILL BRING
GUSTY WINDS AND LARGE SURF TO THE COAST...WITH RAIN SPREADING INLAND
THURSDAY NIGHT AND FRIDAY. RISING SNOW LEVELS WILL LIMIT SNOW TO THE
HIGHEST PEAKS...BUT COLDER AIR BEHIND THE FRONT MAY RESULT IN SOME
SNOW SHOWERS FOR THE CASCADES PASSES FRIDAY EVENING AND SATURDAY.
WARMER AND MOISTER WEATHER IS EXPECTED THIS WEEKEND. THERE IS THE
POTENTIAL FOR AN ATMOSPHERIC RIVER TYPE SET UP AND ASSOCIATED HEAVY
RAIN TO DEVELOP OVER THE WEEKEND INTO EARLY NEXT WEEK.

&&

.EVENING UPDATE...A LOW PRES CIRCULATION IS APPARENT ON SATELLITE AND
RADAR IMAGERY THIS EVENING JUST OFFSHORE OF THE CA/OR BORDER. WATER
VAPOR SATELLITE SHOWS MOISTURE SPREADING NORTHWARD FROM THIS SYSTEM
INTO NW OREGON AND SW WASHINGTON. THERE ARE ALSO LIGHT ECHOES SHOWING
UP ON RADAR OVER THE SOUTHERN AND WESTERN PORTIONS OF OUR FCST
AREA...BUT LITTLE TO NO RAIN IS REACHING THE GROUND AT THIS TIME.
EXPECT AS THE NIGHT GOES ON AND THE OFFSHORE LOW SLOWLY MOVES
NORTHEAST...WE WILL SEE LIGHT PRECIPITATION START TO REACH THE
SURFACE...ESPECIALLY OVER THE HIGHER TERRAIN. A WEAK VORT MAX WILL
ALSO MOVE ONSHORE EARLY WED MORNING...WHICH MAY HELP AID THE SHOWERS.

THE MAIN CHANGE TO THE FCST THIS EVENING WAS TO INCREASE POPS AND QPF
FROM THE 18Z WED TO 12Z THU TIME FRAME. THE CLOSED LOW JUST OFFSHORE
TONIGHT WILL SLOWLY WEAKEN AND PUSH ONSHORE AROUND MIDDAY TOMORROW.
MEANWHILE...THE SHORTWAVE NOW APPARENT ON WATER VAPOR SATELLITE
NEARING 45N 140W IS MODELED TO STRETCH OUT AND PUSH ONSHORE LATER
TOMORROW AFTERNOON AND EVENING. THE LOWER LEVEL MOISTURE ASSOCIATED
WITH THE SURFACE LOW COMBINED WITH THE UPPER LEVEL FORCING FROM THE
SHORTWAVE SHOULD DRIVE A PERIOD OF STEADIER PRECIP LATER TOMORROW
AND TOMORROW NIGHT. THE 00Z NAM AND GFS RUNS PICKED UP ON THIS
PERIOD OF ENHANCED PRECIP. THE VORT MAX PUSHES EAST OF THE CASCADES
BY 12Z THU...AFTER WHICH SHOWER ACTIVITY SHOULD DROP OFF
SIGNIFICANTLY. PYLE

.PREV DISC ISSUED 231 PM PST TUE DEC 17...

.SHORT TERM...TONIGHT THROUGH FRIDAY...SHOWERS HAVE PRETTY MUCH ENDED
OVER THE PORTLAND FORECAST AREA EARLY THIS AFTERNOON...EXCEPT FOR
VERY INFREQUENT ISOLATED SHOWER OVER THE SW WASHINGTON CASCADES.
SATELLITE IMAGERY SHOWS A SURFACE LOW AROUND 150 MILES WEST OF THE
SOUTHERN OREGON COAST...NEAR 42N 127W. THE HIGHER RESOLUTION
MODELS...HRRR AND RAP INITIALIZE BEST WITH THE LOW AND FORECAST RAIN
MOVING NORTH INTO LANE COUNTY SLIGHTLY EARLIER THAN THE OTHER MODELS.
HAVE TRENDED TOWARDS THIS EARLIER ARRIVAL...BUT ONLY HAVE FAIR
CONFIDENCE THAT THE TIMING WILL PAN OUT. ANY RAIN LATE THIS AFTERNOON
SHOULD BE FAIRLY LIGHT AND REMAIN WEST OF THE SOUTH AND CENTRAL
WILLAMETTE VALLEY.

THE LOW WILL MOVE CLOSER TO THE SOUTHERN OREGON COAST LATE THIS
AFTERNOON AND EVENING THEN MOVE ONTO THE CENTRAL OREGON COAST AS AN
UPPER TROUGH LATE TONIGHT...WITH SHOWERS MAINLY OVER THE HIGHER
TERRAIN THROUGH WEDNESDAY MORNING. SOME CLEARING EARLY WED MORNING
MAY RESULT IN SHALLOW FOG AND LOW CLOUDS IN SOME OF THE INTERIOR
VALLEYS...MAINLY SOUTH OF SALEM.

EASTERLY WINDS HAVE HELD ON TODAY WITH A TROUTDALE TO DALLES PRESSURE
GRADIENT HOLDING AROUND 5 MB. THIS GRADIENT SHOULD TIGHTEN A LITTLE
THIS EVENING AS THE LOW MOVES CLOSER TO THE COAST AND MAINTAIN GUSTS
AROUND 30 MPH THROUGH THE WESTERN COLUMBIA RIVER GORGE.

SHOWERS WILL CONTINUE WEDNESDAY...MAINLY FOR THE HIGHER TERRAIN AS
THE PARENT UPPER LEVEL TROUGH MOVES OVER THE PACIFIC NW. SHOWERS
SHOULD END OVERNIGHT AS AN UPPER RIDGE BUILDS OVER THE AREA AND
EXPECT THAT CLEARING SKIES AND LIGHT WINDS WILL LEAD TO SHALLOW FOG
FOR THE INTERIOR VALLEYS EARLY THURSDAY MORNING. MOST OF THURSDAY
WILL BE DRY WITH AN INCREASE OF MID AN HIGH LEVEL CLOUDS IN THE
AFTERNOON.

MODELS ARE IN GOOD AGREEMENT THAT A WELL ORGANIZED FRONT WILL BRING
GUSTY WINDS TO THE COAST THURSDAY EVENING WITH RAIN SPREADING INLAND
THURSDAY NIGHT AND FRIDAY. PRECIPITABLE WATER IS EXPECTED TO BE NEAR
AN INCH AND AN APPROACHING JET STREAK SHOULD PROVIDE GOOD LIFT AND
EXPECT THE HIGHEST RAINFALL TOTALS OF 0.75 TO 1 INCH ACROSS THE
COAST AND COAST RANGE THURSDAY NIGHT THROUGH FRIDAY MORNING. OTHER
AREAS SHOULD SEE BETWEEN 0.4 AND 0.60 INCH OF RAIN. SNOW LEVELS
SHOULD REMAIN ABOVE 5000 FEET DURING THE PEAK RAIN PERIOD...BUT LOWER
TO NEAR OR BELOW THE CASCADE PASSES BEHIND THE FRONT FRIDAY
AFTERNOON.

.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY...A BROAD RIDGE OF HIGH
PRESSURE OVER THE WESTERN U.S. FLATTENS AS A STRONG LOW PRESSURE
SYSTEM OVER THE GULF OF ALASKA MOVES INLAND TO OUR NORTH. AS THIS
TROUGH MOVES ON SHORE SATURDAY...THE ASSOCIATED COLD FRONT MOVES
ONSHORE AND STALLS EAST-TO-WEST ACROSS NORTHWEST OREGON AND
SOUTHWEST WASHINGTON. THIS PUTS OUR AREA IN THE PATH OF RAIN
STARTING SATURDAY THROUGH MONDAY. SOME UNCERTAINTY EXISTS IN WHERE
THIS BOUNDARY WILL SET UP...WHICH WILL DETERMINE HOW MUCH RAINFALL
WE WILL GET. ON TUESDAY...GEFS ENSEMBLE SPAGHETTI PLOTS GET MESSY
AND SIGNIFICANT DIFFERENCES START TO SHOW UP BETWEEN THE GFS AND
ECMWF...DECREASING CONFIDENCE ON HOW THE REST OF THE WEEK WILL SHAPE
UP.  AS OF NOW...THE MOST COMMON SOLUTION IS THAT HIGH PRESSURE
RIDGING WILL START TO BUILD BACK OVER THE WESTERN U.S. WHICH
SUGGESTS DRIER WEATHER STARTING TUESDAY...THOUGH UNCERTAINTY IS VERY
HIGH. -MCCOY

&&

.AVIATION...MOIST SOUTHERLY FLOW ALOFT...WITH PLENTY OF MID AND
HIGH CLOUDS OVER REGION. DO HAVE AREAS OF MVFR CIGS ALONG THE
COAST AND WILL SEE THOSE PERSIST OVERNIGHT INTO WED AM. QUESTION
IS WHETHER OR NOT LOW CLOUDS REFORM S OF SALEM TONIGHT. HAVE
CLEARED OUT AT MOMENT...WITH STILL RATHER HIGH HUMIDITY. SO
SUSPECT WITH OCCASIONAL LIGHT RAIN THERE...WILL SEE AREAS OF IFR
STRATUS REFORM TONIGHT TO SOUTH OF KSLE.

KPDX AND APPROACHES...VFR WILL PERSIST TONIGHT AND WED...BUT CIGS
LOWER TO 5K FT LATER AFTER 09Z WITH OCCASIONAL LIGHT RAIN THROUGH
17Z. VFR WITH LOT OF MID AND HIGH CLOUDS ON WED.ROCKEY.
 &&

.MARINE...NOT MUCH CHANGE. GRADIENTS WEAKENING THIS EVENING AS
LOW HEADS INTO N CALIF. STILL...WILL GET A GUSTS TO 25 KT ON THE
OUTER SOUTH WATERS THIS EVENING. SEAS HOLDING AT 8 TO 9 FT.

NEXT SYSTEM NOW DEVELOPING WAY OFFSHORE BETWEEN 160W-170W. THIS
SYSTEM WILL BRING SOUTHERLY GALES TO THE WATERS LATER THU THROUGH
EARLY FRI AM. STILL SOME UNCERTAINTY ON EXACT TIMING AND DETAILS
BUT WILL BE VERY ACTIVE PERIOD. SEAS LIKELY TO PUSH BACK INTO THE
UPPER TEENS TO NEAR 20 FT BY FRI AM.

MORE FRONTS ARRIVE THIS WEEKEND INTO EARLY NEXT WEEK...WITH
SOUTHERLY GALES LIKELY AND ENHANCED SEAS.   ROCKEY.
&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...GALE WATCH FOR THU AND THU NIGHT ON ALL COASTAL WATERS.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR TONIGHT
AND AGAIN 11 AM TO 4 PM WED.

&&


$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.



000
FXUS66 KSEW 170452
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 PM PST TUE DEC 16 2014

.SYNOPSIS...A WEAK TROUGH WILL BRING AREAS OF LIGHT RAIN TO WESTERN
WASHINGTON THROUGH WEDNESDAY NIGHT. A STRONGER PACIFIC FRONTAL
SYSTEM WILL MOVE THROUGH THE AREA LATE THURSDAY THROUGH FRIDAY WITH
MORE SIGNIFICANT RAIN. A WET WEATHER PATTERN WILL DEVELOP THIS
WEEKEND...WITH HEAVIER RAIN ESPECIALLY AT THE COAST AND IN THE
MOUNTAINS.

&&

.SHORT TERM...A WEAK SYSTEM IS OVER THE OFFSHORE WATERS THIS
EVENING. THE CORE OF THIS FEATURE IS MOVING INTO SOUTHERN OREGON AND
NORTHERN CALIFORNIA...LEAVING THE MUCH WEAKER PORTION OF IT OFF THE
WASHINGTON COAST. SOME PRECIPITATION IS MOVING INTO THE COASTAL
WATERS AT THIS TIME...BUT WESTERN WASHINGTON IS JUST MOSTLY CLOUDY.
TEMPERATURES AT 8 PM WERE IN THE UPPER 30S TO 40S.

THE SYSTEM OFFSHORE WILL WEAKEN FURTHER AS IT MOVES INLAND
TONIGHT...BRINGING SOME LIGHT RAIN TO MAINLY THE COAST AND OLYMPIC
PENINSULA. AREAS OF LIGHT PRECIPITATION WILL SPREAD TO THE WESTERN
WASHINGTON INTERIOR LOWLANDS AND EVENTUALLY THE CASCADES...AS THE
SYSTEM CONTINUES ITS SLOW EASTWARD PROGRESSION. THEN A WEAK UPPER
TROUGH WILL MOVE THROUGH THE FORECAST AREA WEDNESDAY NIGHT FOR SOME
LIGHT SHOWERS.

TOTAL PRECIPITATION FOR THE 36 HOUR PERIOD FROM TONIGHT THROUGH
WEDNESDAY NIGHT WILL GENERALLY BE 0.10 TO 0.25 INCH. THE SNOW LEVEL
WILL BE AROUND 3000 TO 3500 FT...WITH AROUND 1 TO 3 INCHES OF SNOW
IN THE MOUNTAINS.

A SMALL UPPER RIDGE WILL MOVE QUICKLY ACROSS THE FORECAST AREA ON
THURSDAY. A STRONGER FRONTAL SYSTEM WILL BRING MORE SIGNIFICANT
PRECIPITATION TO THE AREA LATE THURSDAY AND THURSDAY NIGHT...
DECREASING ON FRIDAY. STORM TOTAL PRECIPITATION WITH THAT SYSTEM
WILL BE MOSTLY 0.5 TO 1.5 INCHES IN THE MOUNTAINS AND UP TO 0.75
INCHES IN THE LOWLANDS. THE SNOW LEVEL WILL RISE TO 3500 TO 5000 FT
AS THE HEAVIEST PRECIPITATION OCCURS...SO IT COULD ACTUALLY BRING A
DECENT ROUND OF SNOWFALL TO THE SKI AREAS AND HIGHER PASSES AND
MOUNTAIN ROADS. IN ADDITION IT WILL PRODUCE LOCALLY WINDY CONDITIONS
AT THE COAST AND IN THE NORTH INTERIOR.   MCDONNAL

.LONG TERM...HERE IS THE LONG TERM SECTION FROM THE AFTERNOON
DISCUSSION -- GLOBAL MODELS REMAIN IN GOOD AGREEMENT THAT A MORE
CONSOLIDATED WLY FLOW PATTERN DEVELOPS ACROSS THE PACIFIC OVER THE
WEEKEND. THE STRONG WLY JET WILL DIRECT AN ATMOSPHERIC RIVER OF
MOISTURE INTO WRN WA LATER SATURDAY THROUGH  EARLY NEXT WEEK. THE
INITIAL WARM FRONTAL WAVE WILL BRING STRONG SW FLOW ALOFT AND HEAVY
RAIN TO THE MOUNTAINS SATURDAY AFTERNOON AND NIGHT. MODELS DIFFER ON
HOW LONG THE TRAILING MOISTURE PLUM REMAINS DIRECTED INTO WRN WA.
HOWEVER...MOST MODELS SHOW AT LEAST 24-36 HOURS OF HEAVY MOUNTAIN
RAINFALL BEFORE TAPERING OFF WHICH COULD CAUSE SOME CONCERNS FOR
FLOODING ON PRONE RIVERS. SEE THE HYDRO DISCUSSION FOR FURTHER
DETAILS. RAIN AMOUNTS WILL NOT BE NEARLY HAS HEAVY IN THE LOWLANDS
WHICH SHOULD SHADOW EFFICIENTLY FROM SEATTLE/TACOMA NORTH TO EVERETT
GIVEN THE STRONG W-WSW FLOW. HIGH POPS ARE STILL WARRANTED EVEN WITH
LESS QPF AND IT WILL ALSO BE BREEZY AT TIMES...ESPECIALLY ACROSS THE
N INTERIOR/COAST WHICH IS MORE SUSCEPTIBLE TO STRONG SE SURFACE
GRADIENTS.

THE GFS/ECMWF BOTH SHOW A LULL OR BREAK IN PRECIPITATION AROUND
MONDAY OR MONDAY NIGHT. ANOTHER SURFACE LOW FEATURE TRACKS INTO WRN
WA TUESDAY WITH MORE RAIN. IF THERE IS A BREAK AS SHOWN BY CURRENT
MODELS...THEN ADDITIONAL RAINFALL WILL PROBABLY NOT BE
HYDROLOGICALLY SIGNIFICANT. IF THE LOW IS FASTER WITH LITTLE OR NO
BREAK...THEN IT WILL ADD TO FLOODING CONCERNS.

RAIN TRANSITIONS TO SHOWERS SOMETIME MID WEEK. THE 00Z RUNS OF THE
GFS/ECMWF SHOWED A COLDER NLY FLOW PATTERN DEVELOPING. 12/18Z RUNS
ARE COOL AND DRY BY WEDNESDAY BUT NOT NEARLY AS COLD. IT WILL ALL
DEPEND ON THE DEVELOPMENT OF A HIGH OVER KONA LOW. RIDGING OUTSIDE
OF 140 W WOULD DRIVE COLDER NLY FLOW OVER THE PAC NW. INSIDE 140 W
WOULD STILL LIKELY BE DRY BUT NOT AS COLD. TEMPERATURES ARE TRENDED
DOWNWARD SLIGHTLY WITH HIGHS IN THE LOWER 40S BY WEDNESDAY AND LOWS
IN THE 30S. MERCER

&&

.HYDROLOGY...RIVER FLOODING IS NOT EXPECTED THROUGH SATURDAY. MOIST
WESTERLY FLOW WILL DEVELOP SATURDAY NIGHT AND CONTINUE THROUGH
AROUND MONDAY...WITH HEAVY MOUNTAIN RAIN POSSIBLE. MODELS SHOW 3-6+
INCHES OF RAIN IN 36 HOURS FROM SATURDAY NIGHT THROUGH EARLY
MONDAY... WHICH COULD BE ENOUGH TO CAUSE FLOODING ON SOME FLOOD
PRONE RIVERS.   MCDONNAL

&&

.AVIATION...AN UPPER LEVEL TROUGH NEAR THE COAST WILL GIVE LIGHT
SOUTHWEST FLOW ALOFT OVER WESTERN WASHINGTON TONIGHT AND WEDNESDAY.
LOW LEVEL OFFSHORE FLOW WILL GRADUALLY EASE AS A SURFACE TROUGH
MOVES ONSHORE AND SURFACE RIDGING EAST OF THE CASCADES WEAKENS. THE
AIR MASS WILL REMAIN MOIST AND STABLE WITH AREAS OF VERY LIGHT
PRECIPITATION MOVING THROUGH AT TIMES.

BRIEF CLEARING AND INCREASING LOW LEVEL MOISTURE WILL LEAD TO SOME
AREAS OF STRATUS AND/OR FOG OVER THE EXTREME SOUTH SOUND AND
SOUTHWEST INTERIOR OVERNIGHT WHERE SURFACE VSBYS COULD DROP BELOW
1SM AT TIMES THROUGH 15Z. FROM THE CENTRAL PUGET SOUND
NORTHWARD...MAINLY VFR CEILINGS ARE EXPECTED OVERNIGHT BUT WITH
PLENTIFUL HIGH AND MID LEVEL MOISTURE. LATEST MODELS BRING SOME
LIGHT PRECIPITATION INLAND WITH THE SURFACE TROUGH WEDNESDAY
AFTERNOON AND THERE COULD BE SOME HIGHER END MVFR CEILINGS
ASSOCIATED WITH IT.

KSEA...VFR CEILINGS BELOW 050 A TIMES OVERNIGHT INTO WEDNESDAY WITH
SOME LIGHT PRECIP POSSIBLE TOWARD DAYBREAK. EAST-SOUTHEAST WIND 5 TO
10 KNOTS.

&&

.MARINE...OFFSHORE GRADIENTS CONTINUE TO RELAX WITH A WEAK SURFACE
TROUGH APPROACHING THE COASTAL WATERS. SMALL CRAFT ADVISORIES WILL
CONTINUE FOR THE OUTER COASTAL WATERS WHERE BORDERLINE ADVISORY
WINDS AND SEAS NEAR 10 FEET REMAIN POSSIBLE. FOR THE REMAINDER OF
THE WATERS...A PERIOD OF QUIET WEATHER IS FORECAST FOR WEDNESDAY
WITH A WEAK BROAD TROUGH OVER THE REGION. A BETTER ORGANIZED AND
STRONGER FRONT WILL APPROACH THE WATERS LATE THURSDAY. A GALE WATCH
FOR THE COASTAL WATERS MIDDAY THURSDAY THROUGH THURSDAY NIGHT
REMAINS IN EFFECT FOR THIS. A STRONGER FRONT ON SATURDAY COULD
PRODUCE GALES OVER THE NORTHERN INLAND WATERS...ENTRANCES TO THE
STRAIT OF JUAN DE FUCA...AND COASTAL WATERS. LONG PERIOD SWELL IN
EXCESS OF 20 FEET COULD REACH THE COAST ON FRIDAY. 27

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY OUTER COASTAL WATERS.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR ON WEDNESDAY.

&&

$$

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML





000
FXUS66 KSEW 170452
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 PM PST TUE DEC 16 2014

.SYNOPSIS...A WEAK TROUGH WILL BRING AREAS OF LIGHT RAIN TO WESTERN
WASHINGTON THROUGH WEDNESDAY NIGHT. A STRONGER PACIFIC FRONTAL
SYSTEM WILL MOVE THROUGH THE AREA LATE THURSDAY THROUGH FRIDAY WITH
MORE SIGNIFICANT RAIN. A WET WEATHER PATTERN WILL DEVELOP THIS
WEEKEND...WITH HEAVIER RAIN ESPECIALLY AT THE COAST AND IN THE
MOUNTAINS.

&&

.SHORT TERM...A WEAK SYSTEM IS OVER THE OFFSHORE WATERS THIS
EVENING. THE CORE OF THIS FEATURE IS MOVING INTO SOUTHERN OREGON AND
NORTHERN CALIFORNIA...LEAVING THE MUCH WEAKER PORTION OF IT OFF THE
WASHINGTON COAST. SOME PRECIPITATION IS MOVING INTO THE COASTAL
WATERS AT THIS TIME...BUT WESTERN WASHINGTON IS JUST MOSTLY CLOUDY.
TEMPERATURES AT 8 PM WERE IN THE UPPER 30S TO 40S.

THE SYSTEM OFFSHORE WILL WEAKEN FURTHER AS IT MOVES INLAND
TONIGHT...BRINGING SOME LIGHT RAIN TO MAINLY THE COAST AND OLYMPIC
PENINSULA. AREAS OF LIGHT PRECIPITATION WILL SPREAD TO THE WESTERN
WASHINGTON INTERIOR LOWLANDS AND EVENTUALLY THE CASCADES...AS THE
SYSTEM CONTINUES ITS SLOW EASTWARD PROGRESSION. THEN A WEAK UPPER
TROUGH WILL MOVE THROUGH THE FORECAST AREA WEDNESDAY NIGHT FOR SOME
LIGHT SHOWERS.

TOTAL PRECIPITATION FOR THE 36 HOUR PERIOD FROM TONIGHT THROUGH
WEDNESDAY NIGHT WILL GENERALLY BE 0.10 TO 0.25 INCH. THE SNOW LEVEL
WILL BE AROUND 3000 TO 3500 FT...WITH AROUND 1 TO 3 INCHES OF SNOW
IN THE MOUNTAINS.

A SMALL UPPER RIDGE WILL MOVE QUICKLY ACROSS THE FORECAST AREA ON
THURSDAY. A STRONGER FRONTAL SYSTEM WILL BRING MORE SIGNIFICANT
PRECIPITATION TO THE AREA LATE THURSDAY AND THURSDAY NIGHT...
DECREASING ON FRIDAY. STORM TOTAL PRECIPITATION WITH THAT SYSTEM
WILL BE MOSTLY 0.5 TO 1.5 INCHES IN THE MOUNTAINS AND UP TO 0.75
INCHES IN THE LOWLANDS. THE SNOW LEVEL WILL RISE TO 3500 TO 5000 FT
AS THE HEAVIEST PRECIPITATION OCCURS...SO IT COULD ACTUALLY BRING A
DECENT ROUND OF SNOWFALL TO THE SKI AREAS AND HIGHER PASSES AND
MOUNTAIN ROADS. IN ADDITION IT WILL PRODUCE LOCALLY WINDY CONDITIONS
AT THE COAST AND IN THE NORTH INTERIOR.   MCDONNAL

.LONG TERM...HERE IS THE LONG TERM SECTION FROM THE AFTERNOON
DISCUSSION -- GLOBAL MODELS REMAIN IN GOOD AGREEMENT THAT A MORE
CONSOLIDATED WLY FLOW PATTERN DEVELOPS ACROSS THE PACIFIC OVER THE
WEEKEND. THE STRONG WLY JET WILL DIRECT AN ATMOSPHERIC RIVER OF
MOISTURE INTO WRN WA LATER SATURDAY THROUGH  EARLY NEXT WEEK. THE
INITIAL WARM FRONTAL WAVE WILL BRING STRONG SW FLOW ALOFT AND HEAVY
RAIN TO THE MOUNTAINS SATURDAY AFTERNOON AND NIGHT. MODELS DIFFER ON
HOW LONG THE TRAILING MOISTURE PLUM REMAINS DIRECTED INTO WRN WA.
HOWEVER...MOST MODELS SHOW AT LEAST 24-36 HOURS OF HEAVY MOUNTAIN
RAINFALL BEFORE TAPERING OFF WHICH COULD CAUSE SOME CONCERNS FOR
FLOODING ON PRONE RIVERS. SEE THE HYDRO DISCUSSION FOR FURTHER
DETAILS. RAIN AMOUNTS WILL NOT BE NEARLY HAS HEAVY IN THE LOWLANDS
WHICH SHOULD SHADOW EFFICIENTLY FROM SEATTLE/TACOMA NORTH TO EVERETT
GIVEN THE STRONG W-WSW FLOW. HIGH POPS ARE STILL WARRANTED EVEN WITH
LESS QPF AND IT WILL ALSO BE BREEZY AT TIMES...ESPECIALLY ACROSS THE
N INTERIOR/COAST WHICH IS MORE SUSCEPTIBLE TO STRONG SE SURFACE
GRADIENTS.

THE GFS/ECMWF BOTH SHOW A LULL OR BREAK IN PRECIPITATION AROUND
MONDAY OR MONDAY NIGHT. ANOTHER SURFACE LOW FEATURE TRACKS INTO WRN
WA TUESDAY WITH MORE RAIN. IF THERE IS A BREAK AS SHOWN BY CURRENT
MODELS...THEN ADDITIONAL RAINFALL WILL PROBABLY NOT BE
HYDROLOGICALLY SIGNIFICANT. IF THE LOW IS FASTER WITH LITTLE OR NO
BREAK...THEN IT WILL ADD TO FLOODING CONCERNS.

RAIN TRANSITIONS TO SHOWERS SOMETIME MID WEEK. THE 00Z RUNS OF THE
GFS/ECMWF SHOWED A COLDER NLY FLOW PATTERN DEVELOPING. 12/18Z RUNS
ARE COOL AND DRY BY WEDNESDAY BUT NOT NEARLY AS COLD. IT WILL ALL
DEPEND ON THE DEVELOPMENT OF A HIGH OVER KONA LOW. RIDGING OUTSIDE
OF 140 W WOULD DRIVE COLDER NLY FLOW OVER THE PAC NW. INSIDE 140 W
WOULD STILL LIKELY BE DRY BUT NOT AS COLD. TEMPERATURES ARE TRENDED
DOWNWARD SLIGHTLY WITH HIGHS IN THE LOWER 40S BY WEDNESDAY AND LOWS
IN THE 30S. MERCER

&&

.HYDROLOGY...RIVER FLOODING IS NOT EXPECTED THROUGH SATURDAY. MOIST
WESTERLY FLOW WILL DEVELOP SATURDAY NIGHT AND CONTINUE THROUGH
AROUND MONDAY...WITH HEAVY MOUNTAIN RAIN POSSIBLE. MODELS SHOW 3-6+
INCHES OF RAIN IN 36 HOURS FROM SATURDAY NIGHT THROUGH EARLY
MONDAY... WHICH COULD BE ENOUGH TO CAUSE FLOODING ON SOME FLOOD
PRONE RIVERS.   MCDONNAL

&&

.AVIATION...AN UPPER LEVEL TROUGH NEAR THE COAST WILL GIVE LIGHT
SOUTHWEST FLOW ALOFT OVER WESTERN WASHINGTON TONIGHT AND WEDNESDAY.
LOW LEVEL OFFSHORE FLOW WILL GRADUALLY EASE AS A SURFACE TROUGH
MOVES ONSHORE AND SURFACE RIDGING EAST OF THE CASCADES WEAKENS. THE
AIR MASS WILL REMAIN MOIST AND STABLE WITH AREAS OF VERY LIGHT
PRECIPITATION MOVING THROUGH AT TIMES.

BRIEF CLEARING AND INCREASING LOW LEVEL MOISTURE WILL LEAD TO SOME
AREAS OF STRATUS AND/OR FOG OVER THE EXTREME SOUTH SOUND AND
SOUTHWEST INTERIOR OVERNIGHT WHERE SURFACE VSBYS COULD DROP BELOW
1SM AT TIMES THROUGH 15Z. FROM THE CENTRAL PUGET SOUND
NORTHWARD...MAINLY VFR CEILINGS ARE EXPECTED OVERNIGHT BUT WITH
PLENTIFUL HIGH AND MID LEVEL MOISTURE. LATEST MODELS BRING SOME
LIGHT PRECIPITATION INLAND WITH THE SURFACE TROUGH WEDNESDAY
AFTERNOON AND THERE COULD BE SOME HIGHER END MVFR CEILINGS
ASSOCIATED WITH IT.

KSEA...VFR CEILINGS BELOW 050 A TIMES OVERNIGHT INTO WEDNESDAY WITH
SOME LIGHT PRECIP POSSIBLE TOWARD DAYBREAK. EAST-SOUTHEAST WIND 5 TO
10 KNOTS.

&&

.MARINE...OFFSHORE GRADIENTS CONTINUE TO RELAX WITH A WEAK SURFACE
TROUGH APPROACHING THE COASTAL WATERS. SMALL CRAFT ADVISORIES WILL
CONTINUE FOR THE OUTER COASTAL WATERS WHERE BORDERLINE ADVISORY
WINDS AND SEAS NEAR 10 FEET REMAIN POSSIBLE. FOR THE REMAINDER OF
THE WATERS...A PERIOD OF QUIET WEATHER IS FORECAST FOR WEDNESDAY
WITH A WEAK BROAD TROUGH OVER THE REGION. A BETTER ORGANIZED AND
STRONGER FRONT WILL APPROACH THE WATERS LATE THURSDAY. A GALE WATCH
FOR THE COASTAL WATERS MIDDAY THURSDAY THROUGH THURSDAY NIGHT
REMAINS IN EFFECT FOR THIS. A STRONGER FRONT ON SATURDAY COULD
PRODUCE GALES OVER THE NORTHERN INLAND WATERS...ENTRANCES TO THE
STRAIT OF JUAN DE FUCA...AND COASTAL WATERS. LONG PERIOD SWELL IN
EXCESS OF 20 FEET COULD REACH THE COAST ON FRIDAY. 27

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY OUTER COASTAL WATERS.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR ON WEDNESDAY.

&&

$$

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML





000
FXUS66 KSEW 170452
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 PM PST TUE DEC 16 2014

.SYNOPSIS...A WEAK TROUGH WILL BRING AREAS OF LIGHT RAIN TO WESTERN
WASHINGTON THROUGH WEDNESDAY NIGHT. A STRONGER PACIFIC FRONTAL
SYSTEM WILL MOVE THROUGH THE AREA LATE THURSDAY THROUGH FRIDAY WITH
MORE SIGNIFICANT RAIN. A WET WEATHER PATTERN WILL DEVELOP THIS
WEEKEND...WITH HEAVIER RAIN ESPECIALLY AT THE COAST AND IN THE
MOUNTAINS.

&&

.SHORT TERM...A WEAK SYSTEM IS OVER THE OFFSHORE WATERS THIS
EVENING. THE CORE OF THIS FEATURE IS MOVING INTO SOUTHERN OREGON AND
NORTHERN CALIFORNIA...LEAVING THE MUCH WEAKER PORTION OF IT OFF THE
WASHINGTON COAST. SOME PRECIPITATION IS MOVING INTO THE COASTAL
WATERS AT THIS TIME...BUT WESTERN WASHINGTON IS JUST MOSTLY CLOUDY.
TEMPERATURES AT 8 PM WERE IN THE UPPER 30S TO 40S.

THE SYSTEM OFFSHORE WILL WEAKEN FURTHER AS IT MOVES INLAND
TONIGHT...BRINGING SOME LIGHT RAIN TO MAINLY THE COAST AND OLYMPIC
PENINSULA. AREAS OF LIGHT PRECIPITATION WILL SPREAD TO THE WESTERN
WASHINGTON INTERIOR LOWLANDS AND EVENTUALLY THE CASCADES...AS THE
SYSTEM CONTINUES ITS SLOW EASTWARD PROGRESSION. THEN A WEAK UPPER
TROUGH WILL MOVE THROUGH THE FORECAST AREA WEDNESDAY NIGHT FOR SOME
LIGHT SHOWERS.

TOTAL PRECIPITATION FOR THE 36 HOUR PERIOD FROM TONIGHT THROUGH
WEDNESDAY NIGHT WILL GENERALLY BE 0.10 TO 0.25 INCH. THE SNOW LEVEL
WILL BE AROUND 3000 TO 3500 FT...WITH AROUND 1 TO 3 INCHES OF SNOW
IN THE MOUNTAINS.

A SMALL UPPER RIDGE WILL MOVE QUICKLY ACROSS THE FORECAST AREA ON
THURSDAY. A STRONGER FRONTAL SYSTEM WILL BRING MORE SIGNIFICANT
PRECIPITATION TO THE AREA LATE THURSDAY AND THURSDAY NIGHT...
DECREASING ON FRIDAY. STORM TOTAL PRECIPITATION WITH THAT SYSTEM
WILL BE MOSTLY 0.5 TO 1.5 INCHES IN THE MOUNTAINS AND UP TO 0.75
INCHES IN THE LOWLANDS. THE SNOW LEVEL WILL RISE TO 3500 TO 5000 FT
AS THE HEAVIEST PRECIPITATION OCCURS...SO IT COULD ACTUALLY BRING A
DECENT ROUND OF SNOWFALL TO THE SKI AREAS AND HIGHER PASSES AND
MOUNTAIN ROADS. IN ADDITION IT WILL PRODUCE LOCALLY WINDY CONDITIONS
AT THE COAST AND IN THE NORTH INTERIOR.   MCDONNAL

.LONG TERM...HERE IS THE LONG TERM SECTION FROM THE AFTERNOON
DISCUSSION -- GLOBAL MODELS REMAIN IN GOOD AGREEMENT THAT A MORE
CONSOLIDATED WLY FLOW PATTERN DEVELOPS ACROSS THE PACIFIC OVER THE
WEEKEND. THE STRONG WLY JET WILL DIRECT AN ATMOSPHERIC RIVER OF
MOISTURE INTO WRN WA LATER SATURDAY THROUGH  EARLY NEXT WEEK. THE
INITIAL WARM FRONTAL WAVE WILL BRING STRONG SW FLOW ALOFT AND HEAVY
RAIN TO THE MOUNTAINS SATURDAY AFTERNOON AND NIGHT. MODELS DIFFER ON
HOW LONG THE TRAILING MOISTURE PLUM REMAINS DIRECTED INTO WRN WA.
HOWEVER...MOST MODELS SHOW AT LEAST 24-36 HOURS OF HEAVY MOUNTAIN
RAINFALL BEFORE TAPERING OFF WHICH COULD CAUSE SOME CONCERNS FOR
FLOODING ON PRONE RIVERS. SEE THE HYDRO DISCUSSION FOR FURTHER
DETAILS. RAIN AMOUNTS WILL NOT BE NEARLY HAS HEAVY IN THE LOWLANDS
WHICH SHOULD SHADOW EFFICIENTLY FROM SEATTLE/TACOMA NORTH TO EVERETT
GIVEN THE STRONG W-WSW FLOW. HIGH POPS ARE STILL WARRANTED EVEN WITH
LESS QPF AND IT WILL ALSO BE BREEZY AT TIMES...ESPECIALLY ACROSS THE
N INTERIOR/COAST WHICH IS MORE SUSCEPTIBLE TO STRONG SE SURFACE
GRADIENTS.

THE GFS/ECMWF BOTH SHOW A LULL OR BREAK IN PRECIPITATION AROUND
MONDAY OR MONDAY NIGHT. ANOTHER SURFACE LOW FEATURE TRACKS INTO WRN
WA TUESDAY WITH MORE RAIN. IF THERE IS A BREAK AS SHOWN BY CURRENT
MODELS...THEN ADDITIONAL RAINFALL WILL PROBABLY NOT BE
HYDROLOGICALLY SIGNIFICANT. IF THE LOW IS FASTER WITH LITTLE OR NO
BREAK...THEN IT WILL ADD TO FLOODING CONCERNS.

RAIN TRANSITIONS TO SHOWERS SOMETIME MID WEEK. THE 00Z RUNS OF THE
GFS/ECMWF SHOWED A COLDER NLY FLOW PATTERN DEVELOPING. 12/18Z RUNS
ARE COOL AND DRY BY WEDNESDAY BUT NOT NEARLY AS COLD. IT WILL ALL
DEPEND ON THE DEVELOPMENT OF A HIGH OVER KONA LOW. RIDGING OUTSIDE
OF 140 W WOULD DRIVE COLDER NLY FLOW OVER THE PAC NW. INSIDE 140 W
WOULD STILL LIKELY BE DRY BUT NOT AS COLD. TEMPERATURES ARE TRENDED
DOWNWARD SLIGHTLY WITH HIGHS IN THE LOWER 40S BY WEDNESDAY AND LOWS
IN THE 30S. MERCER

&&

.HYDROLOGY...RIVER FLOODING IS NOT EXPECTED THROUGH SATURDAY. MOIST
WESTERLY FLOW WILL DEVELOP SATURDAY NIGHT AND CONTINUE THROUGH
AROUND MONDAY...WITH HEAVY MOUNTAIN RAIN POSSIBLE. MODELS SHOW 3-6+
INCHES OF RAIN IN 36 HOURS FROM SATURDAY NIGHT THROUGH EARLY
MONDAY... WHICH COULD BE ENOUGH TO CAUSE FLOODING ON SOME FLOOD
PRONE RIVERS.   MCDONNAL

&&

.AVIATION...AN UPPER LEVEL TROUGH NEAR THE COAST WILL GIVE LIGHT
SOUTHWEST FLOW ALOFT OVER WESTERN WASHINGTON TONIGHT AND WEDNESDAY.
LOW LEVEL OFFSHORE FLOW WILL GRADUALLY EASE AS A SURFACE TROUGH
MOVES ONSHORE AND SURFACE RIDGING EAST OF THE CASCADES WEAKENS. THE
AIR MASS WILL REMAIN MOIST AND STABLE WITH AREAS OF VERY LIGHT
PRECIPITATION MOVING THROUGH AT TIMES.

BRIEF CLEARING AND INCREASING LOW LEVEL MOISTURE WILL LEAD TO SOME
AREAS OF STRATUS AND/OR FOG OVER THE EXTREME SOUTH SOUND AND
SOUTHWEST INTERIOR OVERNIGHT WHERE SURFACE VSBYS COULD DROP BELOW
1SM AT TIMES THROUGH 15Z. FROM THE CENTRAL PUGET SOUND
NORTHWARD...MAINLY VFR CEILINGS ARE EXPECTED OVERNIGHT BUT WITH
PLENTIFUL HIGH AND MID LEVEL MOISTURE. LATEST MODELS BRING SOME
LIGHT PRECIPITATION INLAND WITH THE SURFACE TROUGH WEDNESDAY
AFTERNOON AND THERE COULD BE SOME HIGHER END MVFR CEILINGS
ASSOCIATED WITH IT.

KSEA...VFR CEILINGS BELOW 050 A TIMES OVERNIGHT INTO WEDNESDAY WITH
SOME LIGHT PRECIP POSSIBLE TOWARD DAYBREAK. EAST-SOUTHEAST WIND 5 TO
10 KNOTS.

&&

.MARINE...OFFSHORE GRADIENTS CONTINUE TO RELAX WITH A WEAK SURFACE
TROUGH APPROACHING THE COASTAL WATERS. SMALL CRAFT ADVISORIES WILL
CONTINUE FOR THE OUTER COASTAL WATERS WHERE BORDERLINE ADVISORY
WINDS AND SEAS NEAR 10 FEET REMAIN POSSIBLE. FOR THE REMAINDER OF
THE WATERS...A PERIOD OF QUIET WEATHER IS FORECAST FOR WEDNESDAY
WITH A WEAK BROAD TROUGH OVER THE REGION. A BETTER ORGANIZED AND
STRONGER FRONT WILL APPROACH THE WATERS LATE THURSDAY. A GALE WATCH
FOR THE COASTAL WATERS MIDDAY THURSDAY THROUGH THURSDAY NIGHT
REMAINS IN EFFECT FOR THIS. A STRONGER FRONT ON SATURDAY COULD
PRODUCE GALES OVER THE NORTHERN INLAND WATERS...ENTRANCES TO THE
STRAIT OF JUAN DE FUCA...AND COASTAL WATERS. LONG PERIOD SWELL IN
EXCESS OF 20 FEET COULD REACH THE COAST ON FRIDAY. 27

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY OUTER COASTAL WATERS.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR ON WEDNESDAY.

&&

$$

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML





000
FXUS66 KSEW 170452
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 PM PST TUE DEC 16 2014

.SYNOPSIS...A WEAK TROUGH WILL BRING AREAS OF LIGHT RAIN TO WESTERN
WASHINGTON THROUGH WEDNESDAY NIGHT. A STRONGER PACIFIC FRONTAL
SYSTEM WILL MOVE THROUGH THE AREA LATE THURSDAY THROUGH FRIDAY WITH
MORE SIGNIFICANT RAIN. A WET WEATHER PATTERN WILL DEVELOP THIS
WEEKEND...WITH HEAVIER RAIN ESPECIALLY AT THE COAST AND IN THE
MOUNTAINS.

&&

.SHORT TERM...A WEAK SYSTEM IS OVER THE OFFSHORE WATERS THIS
EVENING. THE CORE OF THIS FEATURE IS MOVING INTO SOUTHERN OREGON AND
NORTHERN CALIFORNIA...LEAVING THE MUCH WEAKER PORTION OF IT OFF THE
WASHINGTON COAST. SOME PRECIPITATION IS MOVING INTO THE COASTAL
WATERS AT THIS TIME...BUT WESTERN WASHINGTON IS JUST MOSTLY CLOUDY.
TEMPERATURES AT 8 PM WERE IN THE UPPER 30S TO 40S.

THE SYSTEM OFFSHORE WILL WEAKEN FURTHER AS IT MOVES INLAND
TONIGHT...BRINGING SOME LIGHT RAIN TO MAINLY THE COAST AND OLYMPIC
PENINSULA. AREAS OF LIGHT PRECIPITATION WILL SPREAD TO THE WESTERN
WASHINGTON INTERIOR LOWLANDS AND EVENTUALLY THE CASCADES...AS THE
SYSTEM CONTINUES ITS SLOW EASTWARD PROGRESSION. THEN A WEAK UPPER
TROUGH WILL MOVE THROUGH THE FORECAST AREA WEDNESDAY NIGHT FOR SOME
LIGHT SHOWERS.

TOTAL PRECIPITATION FOR THE 36 HOUR PERIOD FROM TONIGHT THROUGH
WEDNESDAY NIGHT WILL GENERALLY BE 0.10 TO 0.25 INCH. THE SNOW LEVEL
WILL BE AROUND 3000 TO 3500 FT...WITH AROUND 1 TO 3 INCHES OF SNOW
IN THE MOUNTAINS.

A SMALL UPPER RIDGE WILL MOVE QUICKLY ACROSS THE FORECAST AREA ON
THURSDAY. A STRONGER FRONTAL SYSTEM WILL BRING MORE SIGNIFICANT
PRECIPITATION TO THE AREA LATE THURSDAY AND THURSDAY NIGHT...
DECREASING ON FRIDAY. STORM TOTAL PRECIPITATION WITH THAT SYSTEM
WILL BE MOSTLY 0.5 TO 1.5 INCHES IN THE MOUNTAINS AND UP TO 0.75
INCHES IN THE LOWLANDS. THE SNOW LEVEL WILL RISE TO 3500 TO 5000 FT
AS THE HEAVIEST PRECIPITATION OCCURS...SO IT COULD ACTUALLY BRING A
DECENT ROUND OF SNOWFALL TO THE SKI AREAS AND HIGHER PASSES AND
MOUNTAIN ROADS. IN ADDITION IT WILL PRODUCE LOCALLY WINDY CONDITIONS
AT THE COAST AND IN THE NORTH INTERIOR.   MCDONNAL

.LONG TERM...HERE IS THE LONG TERM SECTION FROM THE AFTERNOON
DISCUSSION -- GLOBAL MODELS REMAIN IN GOOD AGREEMENT THAT A MORE
CONSOLIDATED WLY FLOW PATTERN DEVELOPS ACROSS THE PACIFIC OVER THE
WEEKEND. THE STRONG WLY JET WILL DIRECT AN ATMOSPHERIC RIVER OF
MOISTURE INTO WRN WA LATER SATURDAY THROUGH  EARLY NEXT WEEK. THE
INITIAL WARM FRONTAL WAVE WILL BRING STRONG SW FLOW ALOFT AND HEAVY
RAIN TO THE MOUNTAINS SATURDAY AFTERNOON AND NIGHT. MODELS DIFFER ON
HOW LONG THE TRAILING MOISTURE PLUM REMAINS DIRECTED INTO WRN WA.
HOWEVER...MOST MODELS SHOW AT LEAST 24-36 HOURS OF HEAVY MOUNTAIN
RAINFALL BEFORE TAPERING OFF WHICH COULD CAUSE SOME CONCERNS FOR
FLOODING ON PRONE RIVERS. SEE THE HYDRO DISCUSSION FOR FURTHER
DETAILS. RAIN AMOUNTS WILL NOT BE NEARLY HAS HEAVY IN THE LOWLANDS
WHICH SHOULD SHADOW EFFICIENTLY FROM SEATTLE/TACOMA NORTH TO EVERETT
GIVEN THE STRONG W-WSW FLOW. HIGH POPS ARE STILL WARRANTED EVEN WITH
LESS QPF AND IT WILL ALSO BE BREEZY AT TIMES...ESPECIALLY ACROSS THE
N INTERIOR/COAST WHICH IS MORE SUSCEPTIBLE TO STRONG SE SURFACE
GRADIENTS.

THE GFS/ECMWF BOTH SHOW A LULL OR BREAK IN PRECIPITATION AROUND
MONDAY OR MONDAY NIGHT. ANOTHER SURFACE LOW FEATURE TRACKS INTO WRN
WA TUESDAY WITH MORE RAIN. IF THERE IS A BREAK AS SHOWN BY CURRENT
MODELS...THEN ADDITIONAL RAINFALL WILL PROBABLY NOT BE
HYDROLOGICALLY SIGNIFICANT. IF THE LOW IS FASTER WITH LITTLE OR NO
BREAK...THEN IT WILL ADD TO FLOODING CONCERNS.

RAIN TRANSITIONS TO SHOWERS SOMETIME MID WEEK. THE 00Z RUNS OF THE
GFS/ECMWF SHOWED A COLDER NLY FLOW PATTERN DEVELOPING. 12/18Z RUNS
ARE COOL AND DRY BY WEDNESDAY BUT NOT NEARLY AS COLD. IT WILL ALL
DEPEND ON THE DEVELOPMENT OF A HIGH OVER KONA LOW. RIDGING OUTSIDE
OF 140 W WOULD DRIVE COLDER NLY FLOW OVER THE PAC NW. INSIDE 140 W
WOULD STILL LIKELY BE DRY BUT NOT AS COLD. TEMPERATURES ARE TRENDED
DOWNWARD SLIGHTLY WITH HIGHS IN THE LOWER 40S BY WEDNESDAY AND LOWS
IN THE 30S. MERCER

&&

.HYDROLOGY...RIVER FLOODING IS NOT EXPECTED THROUGH SATURDAY. MOIST
WESTERLY FLOW WILL DEVELOP SATURDAY NIGHT AND CONTINUE THROUGH
AROUND MONDAY...WITH HEAVY MOUNTAIN RAIN POSSIBLE. MODELS SHOW 3-6+
INCHES OF RAIN IN 36 HOURS FROM SATURDAY NIGHT THROUGH EARLY
MONDAY... WHICH COULD BE ENOUGH TO CAUSE FLOODING ON SOME FLOOD
PRONE RIVERS.   MCDONNAL

&&

.AVIATION...AN UPPER LEVEL TROUGH NEAR THE COAST WILL GIVE LIGHT
SOUTHWEST FLOW ALOFT OVER WESTERN WASHINGTON TONIGHT AND WEDNESDAY.
LOW LEVEL OFFSHORE FLOW WILL GRADUALLY EASE AS A SURFACE TROUGH
MOVES ONSHORE AND SURFACE RIDGING EAST OF THE CASCADES WEAKENS. THE
AIR MASS WILL REMAIN MOIST AND STABLE WITH AREAS OF VERY LIGHT
PRECIPITATION MOVING THROUGH AT TIMES.

BRIEF CLEARING AND INCREASING LOW LEVEL MOISTURE WILL LEAD TO SOME
AREAS OF STRATUS AND/OR FOG OVER THE EXTREME SOUTH SOUND AND
SOUTHWEST INTERIOR OVERNIGHT WHERE SURFACE VSBYS COULD DROP BELOW
1SM AT TIMES THROUGH 15Z. FROM THE CENTRAL PUGET SOUND
NORTHWARD...MAINLY VFR CEILINGS ARE EXPECTED OVERNIGHT BUT WITH
PLENTIFUL HIGH AND MID LEVEL MOISTURE. LATEST MODELS BRING SOME
LIGHT PRECIPITATION INLAND WITH THE SURFACE TROUGH WEDNESDAY
AFTERNOON AND THERE COULD BE SOME HIGHER END MVFR CEILINGS
ASSOCIATED WITH IT.

KSEA...VFR CEILINGS BELOW 050 A TIMES OVERNIGHT INTO WEDNESDAY WITH
SOME LIGHT PRECIP POSSIBLE TOWARD DAYBREAK. EAST-SOUTHEAST WIND 5 TO
10 KNOTS.

&&

.MARINE...OFFSHORE GRADIENTS CONTINUE TO RELAX WITH A WEAK SURFACE
TROUGH APPROACHING THE COASTAL WATERS. SMALL CRAFT ADVISORIES WILL
CONTINUE FOR THE OUTER COASTAL WATERS WHERE BORDERLINE ADVISORY
WINDS AND SEAS NEAR 10 FEET REMAIN POSSIBLE. FOR THE REMAINDER OF
THE WATERS...A PERIOD OF QUIET WEATHER IS FORECAST FOR WEDNESDAY
WITH A WEAK BROAD TROUGH OVER THE REGION. A BETTER ORGANIZED AND
STRONGER FRONT WILL APPROACH THE WATERS LATE THURSDAY. A GALE WATCH
FOR THE COASTAL WATERS MIDDAY THURSDAY THROUGH THURSDAY NIGHT
REMAINS IN EFFECT FOR THIS. A STRONGER FRONT ON SATURDAY COULD
PRODUCE GALES OVER THE NORTHERN INLAND WATERS...ENTRANCES TO THE
STRAIT OF JUAN DE FUCA...AND COASTAL WATERS. LONG PERIOD SWELL IN
EXCESS OF 20 FEET COULD REACH THE COAST ON FRIDAY. 27

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY OUTER COASTAL WATERS.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR ON WEDNESDAY.

&&

$$

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML





000
FXUS66 KSEW 170452
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 PM PST TUE DEC 16 2014

.SYNOPSIS...A WEAK TROUGH WILL BRING AREAS OF LIGHT RAIN TO WESTERN
WASHINGTON THROUGH WEDNESDAY NIGHT. A STRONGER PACIFIC FRONTAL
SYSTEM WILL MOVE THROUGH THE AREA LATE THURSDAY THROUGH FRIDAY WITH
MORE SIGNIFICANT RAIN. A WET WEATHER PATTERN WILL DEVELOP THIS
WEEKEND...WITH HEAVIER RAIN ESPECIALLY AT THE COAST AND IN THE
MOUNTAINS.

&&

.SHORT TERM...A WEAK SYSTEM IS OVER THE OFFSHORE WATERS THIS
EVENING. THE CORE OF THIS FEATURE IS MOVING INTO SOUTHERN OREGON AND
NORTHERN CALIFORNIA...LEAVING THE MUCH WEAKER PORTION OF IT OFF THE
WASHINGTON COAST. SOME PRECIPITATION IS MOVING INTO THE COASTAL
WATERS AT THIS TIME...BUT WESTERN WASHINGTON IS JUST MOSTLY CLOUDY.
TEMPERATURES AT 8 PM WERE IN THE UPPER 30S TO 40S.

THE SYSTEM OFFSHORE WILL WEAKEN FURTHER AS IT MOVES INLAND
TONIGHT...BRINGING SOME LIGHT RAIN TO MAINLY THE COAST AND OLYMPIC
PENINSULA. AREAS OF LIGHT PRECIPITATION WILL SPREAD TO THE WESTERN
WASHINGTON INTERIOR LOWLANDS AND EVENTUALLY THE CASCADES...AS THE
SYSTEM CONTINUES ITS SLOW EASTWARD PROGRESSION. THEN A WEAK UPPER
TROUGH WILL MOVE THROUGH THE FORECAST AREA WEDNESDAY NIGHT FOR SOME
LIGHT SHOWERS.

TOTAL PRECIPITATION FOR THE 36 HOUR PERIOD FROM TONIGHT THROUGH
WEDNESDAY NIGHT WILL GENERALLY BE 0.10 TO 0.25 INCH. THE SNOW LEVEL
WILL BE AROUND 3000 TO 3500 FT...WITH AROUND 1 TO 3 INCHES OF SNOW
IN THE MOUNTAINS.

A SMALL UPPER RIDGE WILL MOVE QUICKLY ACROSS THE FORECAST AREA ON
THURSDAY. A STRONGER FRONTAL SYSTEM WILL BRING MORE SIGNIFICANT
PRECIPITATION TO THE AREA LATE THURSDAY AND THURSDAY NIGHT...
DECREASING ON FRIDAY. STORM TOTAL PRECIPITATION WITH THAT SYSTEM
WILL BE MOSTLY 0.5 TO 1.5 INCHES IN THE MOUNTAINS AND UP TO 0.75
INCHES IN THE LOWLANDS. THE SNOW LEVEL WILL RISE TO 3500 TO 5000 FT
AS THE HEAVIEST PRECIPITATION OCCURS...SO IT COULD ACTUALLY BRING A
DECENT ROUND OF SNOWFALL TO THE SKI AREAS AND HIGHER PASSES AND
MOUNTAIN ROADS. IN ADDITION IT WILL PRODUCE LOCALLY WINDY CONDITIONS
AT THE COAST AND IN THE NORTH INTERIOR.   MCDONNAL

.LONG TERM...HERE IS THE LONG TERM SECTION FROM THE AFTERNOON
DISCUSSION -- GLOBAL MODELS REMAIN IN GOOD AGREEMENT THAT A MORE
CONSOLIDATED WLY FLOW PATTERN DEVELOPS ACROSS THE PACIFIC OVER THE
WEEKEND. THE STRONG WLY JET WILL DIRECT AN ATMOSPHERIC RIVER OF
MOISTURE INTO WRN WA LATER SATURDAY THROUGH  EARLY NEXT WEEK. THE
INITIAL WARM FRONTAL WAVE WILL BRING STRONG SW FLOW ALOFT AND HEAVY
RAIN TO THE MOUNTAINS SATURDAY AFTERNOON AND NIGHT. MODELS DIFFER ON
HOW LONG THE TRAILING MOISTURE PLUM REMAINS DIRECTED INTO WRN WA.
HOWEVER...MOST MODELS SHOW AT LEAST 24-36 HOURS OF HEAVY MOUNTAIN
RAINFALL BEFORE TAPERING OFF WHICH COULD CAUSE SOME CONCERNS FOR
FLOODING ON PRONE RIVERS. SEE THE HYDRO DISCUSSION FOR FURTHER
DETAILS. RAIN AMOUNTS WILL NOT BE NEARLY HAS HEAVY IN THE LOWLANDS
WHICH SHOULD SHADOW EFFICIENTLY FROM SEATTLE/TACOMA NORTH TO EVERETT
GIVEN THE STRONG W-WSW FLOW. HIGH POPS ARE STILL WARRANTED EVEN WITH
LESS QPF AND IT WILL ALSO BE BREEZY AT TIMES...ESPECIALLY ACROSS THE
N INTERIOR/COAST WHICH IS MORE SUSCEPTIBLE TO STRONG SE SURFACE
GRADIENTS.

THE GFS/ECMWF BOTH SHOW A LULL OR BREAK IN PRECIPITATION AROUND
MONDAY OR MONDAY NIGHT. ANOTHER SURFACE LOW FEATURE TRACKS INTO WRN
WA TUESDAY WITH MORE RAIN. IF THERE IS A BREAK AS SHOWN BY CURRENT
MODELS...THEN ADDITIONAL RAINFALL WILL PROBABLY NOT BE
HYDROLOGICALLY SIGNIFICANT. IF THE LOW IS FASTER WITH LITTLE OR NO
BREAK...THEN IT WILL ADD TO FLOODING CONCERNS.

RAIN TRANSITIONS TO SHOWERS SOMETIME MID WEEK. THE 00Z RUNS OF THE
GFS/ECMWF SHOWED A COLDER NLY FLOW PATTERN DEVELOPING. 12/18Z RUNS
ARE COOL AND DRY BY WEDNESDAY BUT NOT NEARLY AS COLD. IT WILL ALL
DEPEND ON THE DEVELOPMENT OF A HIGH OVER KONA LOW. RIDGING OUTSIDE
OF 140 W WOULD DRIVE COLDER NLY FLOW OVER THE PAC NW. INSIDE 140 W
WOULD STILL LIKELY BE DRY BUT NOT AS COLD. TEMPERATURES ARE TRENDED
DOWNWARD SLIGHTLY WITH HIGHS IN THE LOWER 40S BY WEDNESDAY AND LOWS
IN THE 30S. MERCER

&&

.HYDROLOGY...RIVER FLOODING IS NOT EXPECTED THROUGH SATURDAY. MOIST
WESTERLY FLOW WILL DEVELOP SATURDAY NIGHT AND CONTINUE THROUGH
AROUND MONDAY...WITH HEAVY MOUNTAIN RAIN POSSIBLE. MODELS SHOW 3-6+
INCHES OF RAIN IN 36 HOURS FROM SATURDAY NIGHT THROUGH EARLY
MONDAY... WHICH COULD BE ENOUGH TO CAUSE FLOODING ON SOME FLOOD
PRONE RIVERS.   MCDONNAL

&&

.AVIATION...AN UPPER LEVEL TROUGH NEAR THE COAST WILL GIVE LIGHT
SOUTHWEST FLOW ALOFT OVER WESTERN WASHINGTON TONIGHT AND WEDNESDAY.
LOW LEVEL OFFSHORE FLOW WILL GRADUALLY EASE AS A SURFACE TROUGH
MOVES ONSHORE AND SURFACE RIDGING EAST OF THE CASCADES WEAKENS. THE
AIR MASS WILL REMAIN MOIST AND STABLE WITH AREAS OF VERY LIGHT
PRECIPITATION MOVING THROUGH AT TIMES.

BRIEF CLEARING AND INCREASING LOW LEVEL MOISTURE WILL LEAD TO SOME
AREAS OF STRATUS AND/OR FOG OVER THE EXTREME SOUTH SOUND AND
SOUTHWEST INTERIOR OVERNIGHT WHERE SURFACE VSBYS COULD DROP BELOW
1SM AT TIMES THROUGH 15Z. FROM THE CENTRAL PUGET SOUND
NORTHWARD...MAINLY VFR CEILINGS ARE EXPECTED OVERNIGHT BUT WITH
PLENTIFUL HIGH AND MID LEVEL MOISTURE. LATEST MODELS BRING SOME
LIGHT PRECIPITATION INLAND WITH THE SURFACE TROUGH WEDNESDAY
AFTERNOON AND THERE COULD BE SOME HIGHER END MVFR CEILINGS
ASSOCIATED WITH IT.

KSEA...VFR CEILINGS BELOW 050 A TIMES OVERNIGHT INTO WEDNESDAY WITH
SOME LIGHT PRECIP POSSIBLE TOWARD DAYBREAK. EAST-SOUTHEAST WIND 5 TO
10 KNOTS.

&&

.MARINE...OFFSHORE GRADIENTS CONTINUE TO RELAX WITH A WEAK SURFACE
TROUGH APPROACHING THE COASTAL WATERS. SMALL CRAFT ADVISORIES WILL
CONTINUE FOR THE OUTER COASTAL WATERS WHERE BORDERLINE ADVISORY
WINDS AND SEAS NEAR 10 FEET REMAIN POSSIBLE. FOR THE REMAINDER OF
THE WATERS...A PERIOD OF QUIET WEATHER IS FORECAST FOR WEDNESDAY
WITH A WEAK BROAD TROUGH OVER THE REGION. A BETTER ORGANIZED AND
STRONGER FRONT WILL APPROACH THE WATERS LATE THURSDAY. A GALE WATCH
FOR THE COASTAL WATERS MIDDAY THURSDAY THROUGH THURSDAY NIGHT
REMAINS IN EFFECT FOR THIS. A STRONGER FRONT ON SATURDAY COULD
PRODUCE GALES OVER THE NORTHERN INLAND WATERS...ENTRANCES TO THE
STRAIT OF JUAN DE FUCA...AND COASTAL WATERS. LONG PERIOD SWELL IN
EXCESS OF 20 FEET COULD REACH THE COAST ON FRIDAY. 27

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY OUTER COASTAL WATERS.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR ON WEDNESDAY.

&&

$$

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML





000
FXUS66 KSEW 170452
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 PM PST TUE DEC 16 2014

.SYNOPSIS...A WEAK TROUGH WILL BRING AREAS OF LIGHT RAIN TO WESTERN
WASHINGTON THROUGH WEDNESDAY NIGHT. A STRONGER PACIFIC FRONTAL
SYSTEM WILL MOVE THROUGH THE AREA LATE THURSDAY THROUGH FRIDAY WITH
MORE SIGNIFICANT RAIN. A WET WEATHER PATTERN WILL DEVELOP THIS
WEEKEND...WITH HEAVIER RAIN ESPECIALLY AT THE COAST AND IN THE
MOUNTAINS.

&&

.SHORT TERM...A WEAK SYSTEM IS OVER THE OFFSHORE WATERS THIS
EVENING. THE CORE OF THIS FEATURE IS MOVING INTO SOUTHERN OREGON AND
NORTHERN CALIFORNIA...LEAVING THE MUCH WEAKER PORTION OF IT OFF THE
WASHINGTON COAST. SOME PRECIPITATION IS MOVING INTO THE COASTAL
WATERS AT THIS TIME...BUT WESTERN WASHINGTON IS JUST MOSTLY CLOUDY.
TEMPERATURES AT 8 PM WERE IN THE UPPER 30S TO 40S.

THE SYSTEM OFFSHORE WILL WEAKEN FURTHER AS IT MOVES INLAND
TONIGHT...BRINGING SOME LIGHT RAIN TO MAINLY THE COAST AND OLYMPIC
PENINSULA. AREAS OF LIGHT PRECIPITATION WILL SPREAD TO THE WESTERN
WASHINGTON INTERIOR LOWLANDS AND EVENTUALLY THE CASCADES...AS THE
SYSTEM CONTINUES ITS SLOW EASTWARD PROGRESSION. THEN A WEAK UPPER
TROUGH WILL MOVE THROUGH THE FORECAST AREA WEDNESDAY NIGHT FOR SOME
LIGHT SHOWERS.

TOTAL PRECIPITATION FOR THE 36 HOUR PERIOD FROM TONIGHT THROUGH
WEDNESDAY NIGHT WILL GENERALLY BE 0.10 TO 0.25 INCH. THE SNOW LEVEL
WILL BE AROUND 3000 TO 3500 FT...WITH AROUND 1 TO 3 INCHES OF SNOW
IN THE MOUNTAINS.

A SMALL UPPER RIDGE WILL MOVE QUICKLY ACROSS THE FORECAST AREA ON
THURSDAY. A STRONGER FRONTAL SYSTEM WILL BRING MORE SIGNIFICANT
PRECIPITATION TO THE AREA LATE THURSDAY AND THURSDAY NIGHT...
DECREASING ON FRIDAY. STORM TOTAL PRECIPITATION WITH THAT SYSTEM
WILL BE MOSTLY 0.5 TO 1.5 INCHES IN THE MOUNTAINS AND UP TO 0.75
INCHES IN THE LOWLANDS. THE SNOW LEVEL WILL RISE TO 3500 TO 5000 FT
AS THE HEAVIEST PRECIPITATION OCCURS...SO IT COULD ACTUALLY BRING A
DECENT ROUND OF SNOWFALL TO THE SKI AREAS AND HIGHER PASSES AND
MOUNTAIN ROADS. IN ADDITION IT WILL PRODUCE LOCALLY WINDY CONDITIONS
AT THE COAST AND IN THE NORTH INTERIOR.   MCDONNAL

.LONG TERM...HERE IS THE LONG TERM SECTION FROM THE AFTERNOON
DISCUSSION -- GLOBAL MODELS REMAIN IN GOOD AGREEMENT THAT A MORE
CONSOLIDATED WLY FLOW PATTERN DEVELOPS ACROSS THE PACIFIC OVER THE
WEEKEND. THE STRONG WLY JET WILL DIRECT AN ATMOSPHERIC RIVER OF
MOISTURE INTO WRN WA LATER SATURDAY THROUGH  EARLY NEXT WEEK. THE
INITIAL WARM FRONTAL WAVE WILL BRING STRONG SW FLOW ALOFT AND HEAVY
RAIN TO THE MOUNTAINS SATURDAY AFTERNOON AND NIGHT. MODELS DIFFER ON
HOW LONG THE TRAILING MOISTURE PLUM REMAINS DIRECTED INTO WRN WA.
HOWEVER...MOST MODELS SHOW AT LEAST 24-36 HOURS OF HEAVY MOUNTAIN
RAINFALL BEFORE TAPERING OFF WHICH COULD CAUSE SOME CONCERNS FOR
FLOODING ON PRONE RIVERS. SEE THE HYDRO DISCUSSION FOR FURTHER
DETAILS. RAIN AMOUNTS WILL NOT BE NEARLY HAS HEAVY IN THE LOWLANDS
WHICH SHOULD SHADOW EFFICIENTLY FROM SEATTLE/TACOMA NORTH TO EVERETT
GIVEN THE STRONG W-WSW FLOW. HIGH POPS ARE STILL WARRANTED EVEN WITH
LESS QPF AND IT WILL ALSO BE BREEZY AT TIMES...ESPECIALLY ACROSS THE
N INTERIOR/COAST WHICH IS MORE SUSCEPTIBLE TO STRONG SE SURFACE
GRADIENTS.

THE GFS/ECMWF BOTH SHOW A LULL OR BREAK IN PRECIPITATION AROUND
MONDAY OR MONDAY NIGHT. ANOTHER SURFACE LOW FEATURE TRACKS INTO WRN
WA TUESDAY WITH MORE RAIN. IF THERE IS A BREAK AS SHOWN BY CURRENT
MODELS...THEN ADDITIONAL RAINFALL WILL PROBABLY NOT BE
HYDROLOGICALLY SIGNIFICANT. IF THE LOW IS FASTER WITH LITTLE OR NO
BREAK...THEN IT WILL ADD TO FLOODING CONCERNS.

RAIN TRANSITIONS TO SHOWERS SOMETIME MID WEEK. THE 00Z RUNS OF THE
GFS/ECMWF SHOWED A COLDER NLY FLOW PATTERN DEVELOPING. 12/18Z RUNS
ARE COOL AND DRY BY WEDNESDAY BUT NOT NEARLY AS COLD. IT WILL ALL
DEPEND ON THE DEVELOPMENT OF A HIGH OVER KONA LOW. RIDGING OUTSIDE
OF 140 W WOULD DRIVE COLDER NLY FLOW OVER THE PAC NW. INSIDE 140 W
WOULD STILL LIKELY BE DRY BUT NOT AS COLD. TEMPERATURES ARE TRENDED
DOWNWARD SLIGHTLY WITH HIGHS IN THE LOWER 40S BY WEDNESDAY AND LOWS
IN THE 30S. MERCER

&&

.HYDROLOGY...RIVER FLOODING IS NOT EXPECTED THROUGH SATURDAY. MOIST
WESTERLY FLOW WILL DEVELOP SATURDAY NIGHT AND CONTINUE THROUGH
AROUND MONDAY...WITH HEAVY MOUNTAIN RAIN POSSIBLE. MODELS SHOW 3-6+
INCHES OF RAIN IN 36 HOURS FROM SATURDAY NIGHT THROUGH EARLY
MONDAY... WHICH COULD BE ENOUGH TO CAUSE FLOODING ON SOME FLOOD
PRONE RIVERS.   MCDONNAL

&&

.AVIATION...AN UPPER LEVEL TROUGH NEAR THE COAST WILL GIVE LIGHT
SOUTHWEST FLOW ALOFT OVER WESTERN WASHINGTON TONIGHT AND WEDNESDAY.
LOW LEVEL OFFSHORE FLOW WILL GRADUALLY EASE AS A SURFACE TROUGH
MOVES ONSHORE AND SURFACE RIDGING EAST OF THE CASCADES WEAKENS. THE
AIR MASS WILL REMAIN MOIST AND STABLE WITH AREAS OF VERY LIGHT
PRECIPITATION MOVING THROUGH AT TIMES.

BRIEF CLEARING AND INCREASING LOW LEVEL MOISTURE WILL LEAD TO SOME
AREAS OF STRATUS AND/OR FOG OVER THE EXTREME SOUTH SOUND AND
SOUTHWEST INTERIOR OVERNIGHT WHERE SURFACE VSBYS COULD DROP BELOW
1SM AT TIMES THROUGH 15Z. FROM THE CENTRAL PUGET SOUND
NORTHWARD...MAINLY VFR CEILINGS ARE EXPECTED OVERNIGHT BUT WITH
PLENTIFUL HIGH AND MID LEVEL MOISTURE. LATEST MODELS BRING SOME
LIGHT PRECIPITATION INLAND WITH THE SURFACE TROUGH WEDNESDAY
AFTERNOON AND THERE COULD BE SOME HIGHER END MVFR CEILINGS
ASSOCIATED WITH IT.

KSEA...VFR CEILINGS BELOW 050 A TIMES OVERNIGHT INTO WEDNESDAY WITH
SOME LIGHT PRECIP POSSIBLE TOWARD DAYBREAK. EAST-SOUTHEAST WIND 5 TO
10 KNOTS.

&&

.MARINE...OFFSHORE GRADIENTS CONTINUE TO RELAX WITH A WEAK SURFACE
TROUGH APPROACHING THE COASTAL WATERS. SMALL CRAFT ADVISORIES WILL
CONTINUE FOR THE OUTER COASTAL WATERS WHERE BORDERLINE ADVISORY
WINDS AND SEAS NEAR 10 FEET REMAIN POSSIBLE. FOR THE REMAINDER OF
THE WATERS...A PERIOD OF QUIET WEATHER IS FORECAST FOR WEDNESDAY
WITH A WEAK BROAD TROUGH OVER THE REGION. A BETTER ORGANIZED AND
STRONGER FRONT WILL APPROACH THE WATERS LATE THURSDAY. A GALE WATCH
FOR THE COASTAL WATERS MIDDAY THURSDAY THROUGH THURSDAY NIGHT
REMAINS IN EFFECT FOR THIS. A STRONGER FRONT ON SATURDAY COULD
PRODUCE GALES OVER THE NORTHERN INLAND WATERS...ENTRANCES TO THE
STRAIT OF JUAN DE FUCA...AND COASTAL WATERS. LONG PERIOD SWELL IN
EXCESS OF 20 FEET COULD REACH THE COAST ON FRIDAY. 27

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY OUTER COASTAL WATERS.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR ON WEDNESDAY.

&&

$$

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML






000
FXUS66 KOTX 170133
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
533 PM PST TUE DEC 16 2014

.SYNOPSIS...
A more active weather pattern will develop through the week with
periods of light snow in the mountains...and rain or snow in the
valleys. Lower elevations from Interstate 90 south will see mainly
rain...while areas in the Cascades and near the Canadian border
will remain mainly snow. A much stronger weather system over the
weekend will usher in warmer temperatures with sharply rising snow
levels...as well as the potential for windy conditions.


&&

.DISCUSSION...
Evening forecast update to increase precip chances, decrease snow
levels and increase overnight low temperatures. Increased moist
isentropic ascent out ahead of a weak upper level feature has
resulted in widespread light snowfall along and north of the
Highway 2 corridor. Snowflakes will be very fine and contain
have a small moisture content; as a result, I do not anticipated
much if any accumulations from the snow. Best chances for
accumulations will be on grassy surfaces across the northern
mountains where less than a half of an inch will fall over most
locations. Snow will begin to push north of the Spokane/Coeur
d`Alene corridor late this evening.

With current dew point temperatures in the low to mid 30s across
the basin early this evening, I increase low temperatures a bit
warming them into the 30s for most locations. Fog will be possible
due how moist the boundary layer is. Easterly winds may result in
less fog in the Panhandle and portions of extreme easter WA with
better chances for a foggy morning expected in the western basin,
Cascade valleys and northern mtn valleys. /SVH


&&

.AVIATION...
00Z TAFS: A weak weather system this evening will produce light
snow across the Spokane/Coeur d`Alene corridor and light rain at
KEAT and KMWH. Cigs at KGEG, KSFF and KCOE will lower a bit and bounce
between MVFR/VFR. Vis will vary between 2 SM and 6 SM due to the
snow. Easterly flow in the boundary layer will continue to push
moisture across the western basin into the Cascade Mtns where the
lowest cigs between IFR and LIFR will be possible. /SVH


&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        30  38  33  36  33  38 /  70  30  40  30  20  70
Coeur d`Alene  30  40  33  37  31  38 /  60  30  50  50  20  70
Pullman        32  42  34  42  33  41 /  10  10  50  30  20  70
Lewiston       34  42  35  45  34  43 /  10  10  40  30  10  50
Colville       30  36  33  37  33  37 /  70  30  40  30  50  70
Sandpoint      29  36  33  37  30  36 /  50  30  60  60  20  80
Kellogg        31  38  32  38  29  37 /  20  10  70  60  20  70
Moses Lake     32  38  29  38  34  41 /  10  30  20  10  60  50
Wenatchee      34  37  30  37  33  40 /  50  30  30  10  60  50
Omak           29  34  28  34  32  37 /  70  40  40  10  70  60

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$




000
FXUS66 KOTX 170133
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
533 PM PST TUE DEC 16 2014

.SYNOPSIS...
A more active weather pattern will develop through the week with
periods of light snow in the mountains...and rain or snow in the
valleys. Lower elevations from Interstate 90 south will see mainly
rain...while areas in the Cascades and near the Canadian border
will remain mainly snow. A much stronger weather system over the
weekend will usher in warmer temperatures with sharply rising snow
levels...as well as the potential for windy conditions.


&&

.DISCUSSION...
Evening forecast update to increase precip chances, decrease snow
levels and increase overnight low temperatures. Increased moist
isentropic ascent out ahead of a weak upper level feature has
resulted in widespread light snowfall along and north of the
Highway 2 corridor. Snowflakes will be very fine and contain
have a small moisture content; as a result, I do not anticipated
much if any accumulations from the snow. Best chances for
accumulations will be on grassy surfaces across the northern
mountains where less than a half of an inch will fall over most
locations. Snow will begin to push north of the Spokane/Coeur
d`Alene corridor late this evening.

With current dew point temperatures in the low to mid 30s across
the basin early this evening, I increase low temperatures a bit
warming them into the 30s for most locations. Fog will be possible
due how moist the boundary layer is. Easterly winds may result in
less fog in the Panhandle and portions of extreme easter WA with
better chances for a foggy morning expected in the western basin,
Cascade valleys and northern mtn valleys. /SVH


&&

.AVIATION...
00Z TAFS: A weak weather system this evening will produce light
snow across the Spokane/Coeur d`Alene corridor and light rain at
KEAT and KMWH. Cigs at KGEG, KSFF and KCOE will lower a bit and bounce
between MVFR/VFR. Vis will vary between 2 SM and 6 SM due to the
snow. Easterly flow in the boundary layer will continue to push
moisture across the western basin into the Cascade Mtns where the
lowest cigs between IFR and LIFR will be possible. /SVH


&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        30  38  33  36  33  38 /  70  30  40  30  20  70
Coeur d`Alene  30  40  33  37  31  38 /  60  30  50  50  20  70
Pullman        32  42  34  42  33  41 /  10  10  50  30  20  70
Lewiston       34  42  35  45  34  43 /  10  10  40  30  10  50
Colville       30  36  33  37  33  37 /  70  30  40  30  50  70
Sandpoint      29  36  33  37  30  36 /  50  30  60  60  20  80
Kellogg        31  38  32  38  29  37 /  20  10  70  60  20  70
Moses Lake     32  38  29  38  34  41 /  10  30  20  10  60  50
Wenatchee      34  37  30  37  33  40 /  50  30  30  10  60  50
Omak           29  34  28  34  32  37 /  70  40  40  10  70  60

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 170001
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
401 PM PST TUE DEC 16 2014

.SYNOPSIS...
A more active weather pattern will develop through the week with
periods of light snow in the mountains...and rain or snow in the
valleys. Lower elevations from Interstate 90 south will see mainly
rain...while areas in the Cascades and near the Canadian border
will remain mainly snow. A much stronger weather system over the
weekend will usher in warmer temperatures with sharply rising snow
levels...as well as the potential for windy conditions.

&&

.DISCUSSION...

Tonight into Tomorrow...Forecast remains fairly cluttered with
pops of widely varying value yet the precipitation amounts remain
on the low side going into tomorrow. They remain assigned to the
extreme north and within the vicinity of the East Slopes of the
North Cascades and Northern Mountains with a weak exiting weather
disturbance. A second disturbance noted with a cluster of moderate
to high pops passes within close proximity to the West Plains of
Spokane, Eastern Lincoln, Northeast Adams, and Northwest Whitman
Counties and by 3Z its should be up in the northern mountains and
weakened considerably. Amounts of rain or snow expected to fall
out of this small circulation are on the light side on the order
of .05 liquid or less. After these features leave the area fog and
low clouds should fill back in just in time to be overrun in a
somewhat similar fashion with yet another weak upper level
disturbance passage tomorrow. Given this fairly stagnant pattern
is lacking any substantial amount of either cold dry air or snow-
cover the forecast temperatures remain on the warm side of what
would be considered normal for this time of year. /Pelatti

Wednesday night through Saturday...A gradually more active pattern
will evolve for the middle to end of the week.

A weak short wave trough will track across Eastern Washington and
North Idaho Wednesday night into Thursday morning. This combined
with upslope flow into Northeast Washington and the Idaho
Panhandle will yield light snow accumulations mainly above 2500
feet per forecast soundings.

The next system enters Thursday night into Friday in the form of a
weak cold front. Cloud cover looks to thicken early Thursday
evening which will limit radiational cooling potential. There are
some minor differences regarding the lower level thermal profiles
from the NAM, GFS, and ECMWF...with the NAM and ECMWF the warmest.
Given a continued modification of the low level air mass through
Thursday with weak systems passing through...and lack of
radiational cooling potential Thu night...forecast leans towards
the warmer high resolution NAM/ECMWF models. However even if the
cooler GFS verifies the best potential for accumulations would be
north of Interstate 90...with Spokane/Coeur D`Alene likely seeing
a non-accumulating wet snow. Models suggest the potential for
light snow accumulations in the Cascades, Okanogan Highlands,
Waterville Plateau, Wenatchee area above 1000-1500 feet...northern
valleys above 2000-2500 feet...and in the mountains.

After a brief break Friday night...a much wetter system approaches
for the weekend. GFS and ECMWF show precip developing over
Central Washington Saturday afternoon as a warm front approaches.
Thermal profiles suggest mainly snow north and west of Moses
Lake...and mainly rain from Interstate 90 south Saturday
afternoon. JW

...A VERY WET WARM AND WINDY SYSTEM IS EXPECTED SATURDAY NIGHT
THROUGH MONDAY...

Saturday night through Monday...Model guidance is still remaining
quite consistent on bringing a strong storm into the region
during this period. This storm is currently just heading east of
Japan and looks fairly impressive on water vapor imagery. By the
time it nears the western US...it flattens our currently elongated
trough pattern and brings in very energetic zonal or westerly
flow. The upper level jet stream associated with this zonal flow
is still forecast to near 150 kts which will help advect ample
moisture into the region via a large atmospheric river. Model
guidance also remains very consistent on showing the leading edge
of the river on the coast by late Saturday afternoon and bringing
it across the Cascades overnight. This means we will see
widespread precipitation beginning sometime Saturday night and
continuing through most of Sunday. Given that the precipitation
will be largely derived from swift westerly flow in the 850-700 mb
layer we should see a rapid ending of the precipitation in the lee
of the Cascades sometime on Sunday as the strong warm air
advection in that layer turns to neutral or weak cold air
advection. The main story then will turn to wind and warm
temperatures. Before that occurs though...we expect all locations
to see some precipitation...much of which will be heavy along the
Cascade crest and likely over the Idaho Panhandle. 24 hr
precipitation amounts between Saturday night and Sunday night will
likely range from 1-2.5 inches along much of the crest to
0.75-1.50 inches over the Panhandle. Meanwhile amounts will be
substantially lower over the areas in between given the swift
westerly flow. Despite these lofty precipitation amounts...most
will fall as rain as snow levels will initially begin near the
valleys floors in the Cascades rising to nearly 4-6k feet by
Sunday along the Canadian border and much higher near the Oregon
border. So this is not expected to be a good snow event. During
the rising snow level period...we could also see a brief period of
freezing rain near the Cascades, especially south of Lake Chelan.
The threat of precipitation will gradually wind down across the
region on Monday as the atmospheric river begins to sag south of
the forecast area.

So as the precipitation threat eases over most of Washington between
the Cascades and Idaho Panhandle mountains we anticipate a very
warm and breezy period. The UW MM5 model is showing sustained
surface winds of 25-30 mph so we`d expect the possibility of gusts
from 40-50 mph if the models hold to this notion. Meanwhile
temperatures will surge to levels much warmer than normal for this
time of year. Widespread temperatures in the 40s to mid 50s can be
expected so any snow which falls through the end of this week
would certainly melt. This weather pattern will somewhat similar
to what t we encountered just about a week ago on the tenth and
eleventh, just perhaps not quite as warm. Winds will also be a
little more widespread.

Monday night and Tuesday...The atmospheric river is expected to be
well south of the forecast however there will be enough moisture
left behind to keep some orographic precipitation left in the
forecast. Again most will occur near the Cascades and perhaps the
southern half of the Idaho Panhandle. Temperatures will begin to
cool down somewhat as the upper level jet sags atop the region
allowing slightly cooler air to move into the region. By this
point snow levels will be sufficiently low to bring snow to
elevations between 3-4k feet. Amounts should not be terribly heavy
however. fx

&&

.AVIATION...
00Z TAFS: A weak weather system this evening will produce light
snow across the Spokane/Coeur d`Alene corridor and light rain at
KEAT and KMWH. Cigs at KGEG, KSFF and KCOE will lower a bit and bounce
between MVFR/VFR. Vis will vary between 2 SM and 6 SM due to the
snow. Easterly flow in the boundary layer will continue to push
moisture across the western basin into the Cascade Mtns where the
lowest cigs between IFR and LIFR will be possible. /SVH

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        29  38  33  36  33  38 /  50  30  40  30  20  70
Coeur d`Alene  30  40  33  37  31  38 /  30  30  50  50  20  70
Pullman        29  42  34  42  33  41 /  30  10  50  30  20  70
Lewiston       32  42  35  45  34  43 /  10  10  40  30  10  50
Colville       28  36  33  37  33  37 /  40  30  40  30  50  70
Sandpoint      28  36  33  37  30  36 /  20  30  60  60  20  80
Kellogg        30  38  32  38  29  37 /  20  10  70  60  20  70
Moses Lake     28  38  29  38  34  41 /  10  30  20  10  60  50
Wenatchee      31  37  30  37  33  40 /  60  30  30  10  60  50
Omak           26  34  28  34  32  37 /  60  40  40  10  70  60

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$




000
FXUS66 KOTX 170001
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
401 PM PST TUE DEC 16 2014

.SYNOPSIS...
A more active weather pattern will develop through the week with
periods of light snow in the mountains...and rain or snow in the
valleys. Lower elevations from Interstate 90 south will see mainly
rain...while areas in the Cascades and near the Canadian border
will remain mainly snow. A much stronger weather system over the
weekend will usher in warmer temperatures with sharply rising snow
levels...as well as the potential for windy conditions.

&&

.DISCUSSION...

Tonight into Tomorrow...Forecast remains fairly cluttered with
pops of widely varying value yet the precipitation amounts remain
on the low side going into tomorrow. They remain assigned to the
extreme north and within the vicinity of the East Slopes of the
North Cascades and Northern Mountains with a weak exiting weather
disturbance. A second disturbance noted with a cluster of moderate
to high pops passes within close proximity to the West Plains of
Spokane, Eastern Lincoln, Northeast Adams, and Northwest Whitman
Counties and by 3Z its should be up in the northern mountains and
weakened considerably. Amounts of rain or snow expected to fall
out of this small circulation are on the light side on the order
of .05 liquid or less. After these features leave the area fog and
low clouds should fill back in just in time to be overrun in a
somewhat similar fashion with yet another weak upper level
disturbance passage tomorrow. Given this fairly stagnant pattern
is lacking any substantial amount of either cold dry air or snow-
cover the forecast temperatures remain on the warm side of what
would be considered normal for this time of year. /Pelatti

Wednesday night through Saturday...A gradually more active pattern
will evolve for the middle to end of the week.

A weak short wave trough will track across Eastern Washington and
North Idaho Wednesday night into Thursday morning. This combined
with upslope flow into Northeast Washington and the Idaho
Panhandle will yield light snow accumulations mainly above 2500
feet per forecast soundings.

The next system enters Thursday night into Friday in the form of a
weak cold front. Cloud cover looks to thicken early Thursday
evening which will limit radiational cooling potential. There are
some minor differences regarding the lower level thermal profiles
from the NAM, GFS, and ECMWF...with the NAM and ECMWF the warmest.
Given a continued modification of the low level air mass through
Thursday with weak systems passing through...and lack of
radiational cooling potential Thu night...forecast leans towards
the warmer high resolution NAM/ECMWF models. However even if the
cooler GFS verifies the best potential for accumulations would be
north of Interstate 90...with Spokane/Coeur D`Alene likely seeing
a non-accumulating wet snow. Models suggest the potential for
light snow accumulations in the Cascades, Okanogan Highlands,
Waterville Plateau, Wenatchee area above 1000-1500 feet...northern
valleys above 2000-2500 feet...and in the mountains.

After a brief break Friday night...a much wetter system approaches
for the weekend. GFS and ECMWF show precip developing over
Central Washington Saturday afternoon as a warm front approaches.
Thermal profiles suggest mainly snow north and west of Moses
Lake...and mainly rain from Interstate 90 south Saturday
afternoon. JW

...A VERY WET WARM AND WINDY SYSTEM IS EXPECTED SATURDAY NIGHT
THROUGH MONDAY...

Saturday night through Monday...Model guidance is still remaining
quite consistent on bringing a strong storm into the region
during this period. This storm is currently just heading east of
Japan and looks fairly impressive on water vapor imagery. By the
time it nears the western US...it flattens our currently elongated
trough pattern and brings in very energetic zonal or westerly
flow. The upper level jet stream associated with this zonal flow
is still forecast to near 150 kts which will help advect ample
moisture into the region via a large atmospheric river. Model
guidance also remains very consistent on showing the leading edge
of the river on the coast by late Saturday afternoon and bringing
it across the Cascades overnight. This means we will see
widespread precipitation beginning sometime Saturday night and
continuing through most of Sunday. Given that the precipitation
will be largely derived from swift westerly flow in the 850-700 mb
layer we should see a rapid ending of the precipitation in the lee
of the Cascades sometime on Sunday as the strong warm air
advection in that layer turns to neutral or weak cold air
advection. The main story then will turn to wind and warm
temperatures. Before that occurs though...we expect all locations
to see some precipitation...much of which will be heavy along the
Cascade crest and likely over the Idaho Panhandle. 24 hr
precipitation amounts between Saturday night and Sunday night will
likely range from 1-2.5 inches along much of the crest to
0.75-1.50 inches over the Panhandle. Meanwhile amounts will be
substantially lower over the areas in between given the swift
westerly flow. Despite these lofty precipitation amounts...most
will fall as rain as snow levels will initially begin near the
valleys floors in the Cascades rising to nearly 4-6k feet by
Sunday along the Canadian border and much higher near the Oregon
border. So this is not expected to be a good snow event. During
the rising snow level period...we could also see a brief period of
freezing rain near the Cascades, especially south of Lake Chelan.
The threat of precipitation will gradually wind down across the
region on Monday as the atmospheric river begins to sag south of
the forecast area.

So as the precipitation threat eases over most of Washington between
the Cascades and Idaho Panhandle mountains we anticipate a very
warm and breezy period. The UW MM5 model is showing sustained
surface winds of 25-30 mph so we`d expect the possibility of gusts
from 40-50 mph if the models hold to this notion. Meanwhile
temperatures will surge to levels much warmer than normal for this
time of year. Widespread temperatures in the 40s to mid 50s can be
expected so any snow which falls through the end of this week
would certainly melt. This weather pattern will somewhat similar
to what t we encountered just about a week ago on the tenth and
eleventh, just perhaps not quite as warm. Winds will also be a
little more widespread.

Monday night and Tuesday...The atmospheric river is expected to be
well south of the forecast however there will be enough moisture
left behind to keep some orographic precipitation left in the
forecast. Again most will occur near the Cascades and perhaps the
southern half of the Idaho Panhandle. Temperatures will begin to
cool down somewhat as the upper level jet sags atop the region
allowing slightly cooler air to move into the region. By this
point snow levels will be sufficiently low to bring snow to
elevations between 3-4k feet. Amounts should not be terribly heavy
however. fx

&&

.AVIATION...
00Z TAFS: A weak weather system this evening will produce light
snow across the Spokane/Coeur d`Alene corridor and light rain at
KEAT and KMWH. Cigs at KGEG, KSFF and KCOE will lower a bit and bounce
between MVFR/VFR. Vis will vary between 2 SM and 6 SM due to the
snow. Easterly flow in the boundary layer will continue to push
moisture across the western basin into the Cascade Mtns where the
lowest cigs between IFR and LIFR will be possible. /SVH

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        29  38  33  36  33  38 /  50  30  40  30  20  70
Coeur d`Alene  30  40  33  37  31  38 /  30  30  50  50  20  70
Pullman        29  42  34  42  33  41 /  30  10  50  30  20  70
Lewiston       32  42  35  45  34  43 /  10  10  40  30  10  50
Colville       28  36  33  37  33  37 /  40  30  40  30  50  70
Sandpoint      28  36  33  37  30  36 /  20  30  60  60  20  80
Kellogg        30  38  32  38  29  37 /  20  10  70  60  20  70
Moses Lake     28  38  29  38  34  41 /  10  30  20  10  60  50
Wenatchee      31  37  30  37  33  40 /  60  30  30  10  60  50
Omak           26  34  28  34  32  37 /  60  40  40  10  70  60

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KSEW 162348
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 PM PST TUE DEC 16 2014

.SYNOPSIS...A WEAK TROUGH WILL BRING SPOTTY LIGHT RAIN TO WESTERN
WASHINGTON THROUGH WEDNESDAY NIGHT. A STRONGER PACIFIC FRONTAL
SYSTEM IS FORECAST TO ARRIVE LATER THURSDAY INTO FRIDAY WITH MORE
WIDESPREAD RAIN. YET ANOTHER SYSTEM MAY BRING HEAVY RAIN AT TIMES TO
THE MOUNTAINS AND COAST SUNDAY INTO EARLY NEXT WEEK.
&&

.SHORT TERM...RADAR AND SATELLITE IMAGERY INDICATE CLOUDS AND SOME
SPOTTY LIGHT RAIN ACROSS WRN WA THIS AFTERNOON. THE UPPER LEVEL
TROUGH AXIS STILL OFFSHORE IS PROVIDING MOIST SLY FLOW OVER THE
AREA. DYNAMIC LIFT IS WEAK GIVEN THE SPLIT FLOW ALOFT AND WITH THE
SURFACE TROUGH. THEREFORE...MEASURABLE RAIN IS NOT VERY WIDESPREAD
AND IS MAINLY CONFINED TO THE S AND W OF PUGET SOUND. LIGHT
PRECIPITATION SHOULD EASE OFF OR END FOR A TIME THIS EVENING AS THE
BULK OF MOISTURE AND LIFT DIVES SE INTO CA/OREGON.

THE NRN BRANCH UPPER TROUGH AXIS MOVES THROUGH WRN WA LATER TONIGHT
AND WEDNESDAY. MODELS GENERALLY DEPICT WEAK LIFT AND ONLY LIGHT
SPOTTY QPF FIELDS OVER THE HIGHER TERRAIN OF WRN WA. HOWEVER...THE
21Z HRRR SHOWS MOISTURE FROM THE SRN STREAM SYSTEM BECOMING
ENTRAINED NWD AHEAD OF THE NRN BRANCH TROUGH LATE TONIGHT. THIS IS
DIFFERENT FROM THE GFS40 WHICH SHOWS A MORE PRONOUNCED SPLIT AND
MEAGER QPF FIELDS. SINCE MODELS HAVE NOT SETTLED ON THE DEGREE OF
SPLITTING...SOME CHANCE POPS WILL REMAIN IN THE FORECAST FOR WRN WA
THROUGH WEDNESDAY. THE TROUGH AXIS SHIFTS EWD WEDNESDAY NIGHT WITH
SHOWERS ENDING.

A WEAK RIDGE ALOFT IS STILL EXPECTED TO SHIFT ACROSS WA ON THURSDAY.
MODELS CONTINUE TO DIFFER ON THE TIMING OF THE NEXT SOMEWHAT
STRONGER SYSTEM TO ARRIVE. THE 18Z GFS/12Z ECMWF AND NAM12 SHOW RAIN
HOLDING OFF UNTIL LATE THURSDAY AFTERNOON. THIS IS SLOWER THAN SOME
PAST RUNS AND SLOWER THAN THE 12Z CANADIAN. A STRONG 180+ KT JET
ACROSS THE PACIFIC PUTS THE SLOWER TIMING INTO QUESTION AND WILL OPT
TO LEAVE A CHANCE OF RAIN IN THE FORECAST.

THE FRONT PUSHES THROUGH WRN WA THURSDAY NIGHT BUT WILL
SPLIT...THOUGH LATER THAN PREVIOUS SYSTEMS. QPF AMOUNTS SHOULD BE
MORE WIDESPREAD AND COULD APPROACH A HALF INCH IN THE MOUNTAINS.
SNOW LEVELS WILL BE LOWER THAN WITH PAST SYSTEMS SO A FEW INCHES
DOWN TO 4000 FEET IS POSSIBLE. HIGHER ELEVATIONS SUCH AS THE SKI
RESORTS COULD GET 6 INCHES IF THE SYSTEM DOES NOT SPLIT TOO
SEVERELY. LOWLAND RAIN WILL CHANGE OVER TO SHOWERS LATE FRIDAY OR
FRIDAY NIGHT AHEAD OF THE NEXT STORM SYSTEM.

.LONG TERM...GLOBAL MODELS REMAIN IN GOOD AGREEMENT THAT A MORE
CONSOLIDATED WLY FLOW PATTERN DEVELOPS ACROSS THE PACIFIC OVER THE
WEEKEND. THE STRONG WLY JET WILL DIRECT AN ATMOSPHERIC RIVER OF
MOISTURE INTO WRN WA LATER SATURDAY THROUGH  EARLY NEXT WEEK. THE
INITIAL WARM FRONTAL WAVE WILL BRING STRONG SW FLOW ALOFT AND HEAVY
RAIN TO THE MOUNTAINS SATURDAY AFTERNOON AND NIGHT. MODELS DIFFER ON
HOW LONG THE TRAILING MOISTURE PLUM REMAINS DIRECTED INTO WRN WA.
HOWEVER...MOST MODELS SHOW AT LEAST 24-36 HOURS OF HEAVY MOUNTAIN
RAINFALL BEFORE TAPERING OFF WHICH COULD CAUSE SOME CONCERNS FOR
FLOODING ON PRONE RIVERS. SEE THE HYDRO DISCUSSION FOR FURTHER
DETAILS. RAIN AMOUNTS WILL NOT BE NEARLY HAS HEAVY IN THE LOWLANDS
WHICH SHOULD SHADOW EFFICIENTLY FROM SEATTLE/TACOMA NORTH TO EVERETT
GIVEN THE STRONG W-WSW FLOW. HIGH POPS ARE STILL WARRANTED EVEN WITH
LESS QPF AND IT WILL ALSO BE BREEZY AT TIMES...ESPECIALLY ACROSS THE
N INTERIOR/COAST WHICH IS MORE SUSCEPTIBLE TO STRONG SE SURFACE
GRADIENTS.

THE GFS/ECMWF BOTH SHOW A LULL OR BREAK IN PRECIPITATION AROUND
MONDAY OR MONDAY NIGHT. ANOTHER SURFACE LOW FEATURE TRACKS INTO WRN
WA TUESDAY WITH MORE RAIN. IF THERE IS A BREAK AS SHOWN BY CURRENT
MODELS...THEN ADDITIONAL RAINFALL WILL PROBABLY NOT BE
HYDROLOGICALLY SIGNIFICANT. IF THE LOW IS FASTER WITH LITTLE OR NO
BREAK...THEN IT WILL ADD TO FLOODING CONCERNS.

RAIN TRANSITIONS TO SHOWERS SOMETIME MID WEEK. THE 00Z RUNS OF THE
GFS/ECMWF SHOWED A COLDER NLY FLOW PATTERN DEVELOPING. 12/18Z RUNS
ARE COOL AND DRY BY WEDNESDAY BUT NOT NEARLY AS COLD. IT WILL ALL
DEPEND ON THE DEVELOPMENT OF A HIGH OVER KONA LOW. RIDGING OUTSIDE
OF 140 W WOULD DRIVE COLDER NLY FLOW OVER THE PAC NW. INSIDE 140 W
WOULD STILL LIKELY BE DRY BUT NOT AS COLD. TEMPERATURES ARE TRENDED
DOWNWARD SLIGHTLY WITH HIGHS IN THE LOWER 40S BY WEDNESDAY AND LOWS
IN THE 30S. MERCER

&&

.HYDROLOGY...RIVER FLOODING IS NOT EXPECTED THROUGH SATURDAY. A
MOIST WESTERLY FLOW PATTERN WILL DEVELOP SATURDAY NIGHT THROUGH
EARLY NEXT WEEK. THE COMBINATION OF STRONG FLOW AND A LONG MOISTURE
FETCH MEANS HEAVY MOUNTAIN RAIN IS POSSIBLE IF THE FRONTAL SYSTEM IS
DIRECTED INTO WRN WA. MOST MODEL RUNS SHOW A POTENTIAL FOR 3-6+
INCHES OF RAIN IN 36 HOURS FROM SATURDAY NIGHT THROUGH EARLY MONDAY.
THIS IS POSSIBLY ENOUGH TO CAUSE FLOODING ON SOME OF THE MORE FLOOD
PRONE RIVERS. THE EXTENDED FORECAST SHOULD BE MONITORED CLOSELY. AN
EXTENDED FLOOD OUTLOOK WILL BE ISSUED IF FLOODING BECOMES MORE
CERTAIN.  MERCER

&&

.AVIATION...AN UPPER LEVEL TROUGH OVER THE COASTAL WATERS COMBINED
WITH HIGH PRESSURE WELL EAST OF THE AREA IS GIVING LIGHT SOUTHERLY
FLOW ALOFT. AT THE SURFACE...HIGH PRESSURE EAST OF THE CASCADES
COMBINED WITH A TROUGH OF LOW PRESSURE OFFSHORE IS GIVING LOW LEVEL
OFFSHORE FLOW. THE TROUGH WILL MOVE INLAND ON WEDNESDAY. THE AIR
MASS IS MOIST AND STABLE...EXCEPT IS DRY AT LOW LEVELS OVER THE
INTERIOR VALLEYS. THE AIR MASS WILL BECOME DRIER TONIGHT THROUGH
WEDNESDAY.

DESPITE ABUNDANT CLOUD COVER AND LIGHT PRECIPITATION...LOW LEVEL
OFFSHORE FLOW IS GIVING VFR CONDITIONS TO THE INTERIOR OF WESTERN
WASHINGTON WITH GOOD VISIBILITY AND CEILINGS AROUND FLIGHT LEVEL
035. MARGINAL VFR CEILINGS AND VISIBILITIES ARE OCCURRING ON THE
NORTH COAST AND LOCAL CEILINGS AROUND FLIGHT LEVEL 010-015 ARE BEING
OBSERVED AROUND KOLM. THE LATEST NAM12 AND GFS SOLUTIONS SUGGEST
THAT THE LOWER AND MID LEVELS OF THE AIR MASS WILL DRY TONIGHT AS
THE WEAK TROUGH THAT IS IN THE COASTAL WATERS MOVES ONSHORE. ANY
CLEARING MAY RESULT IN LOCAL IFR CEILINGS AND VISIBILITIES IN
STRATUS AND FOG LATE TONIGHT INTO WED MORNING...ESPECIALLY IN FOG
PRONE VALLEYS SUCH AS AT KOLM. THE LATEST HRRR SHOWS PRECIPITATION
TO THE NE OF A LOW MOVING IN AROUND THE EXTREME SOUTH OREGON COAST
WILL SHOOT NE INTO THE AREA OVERNIGHT. WILL MONITOR SATELLITE AND
RADAR FOR THIS POSSIBILITY...BUT THE INCREASING RAIN SCENARIO
APPEARS UNLIKELY AT THIS TIME GIVEN THE STRENGTH OF THE SPLIT FLOW
ALONG THE WEST COAST. AT THIS TIME THE 00Z TERMINALS WILL FOLLOW THE
NAM12/GFS SCENARIO AND WILL BE SIMILAR TO THE PREVIOUS PACKAGE.
ALBRECHT

KSEA...VFR CONDITIONS WILL CONTINUE WITH BKN-OVC035 OVC060...
PERIODS OF VERY LIGHT RAIN AND VISIBILITIES 6KM OR HIGHER. CEILINGS
ARE EXPECTED TO IMPROVE AND RAIN CHANCES DECREASE ABOUT 04Z THIS
EVENING. EXPECT EAST WINDS 6 TO 9 KT TONIGHT. ALBRECHT

&&

.MARINE...HIGH PRESSURE EAST OF THE CASCADES COMBINED WITH A TROUGH
OF LOW PRESSURE OVER THE COASTAL WATERS IS GIVING LIGHT OFFSHORE
FLOW TO THE AREA. THIS OFFSHORE FLOW WILL CONTINUE TO GRADUALLY EASE
OVERNIGHT AS THE TROUGH SLOWLY MOVES TOWARD THE COASTLINE. A SMALL
CRAFT ADVISORY CONTINUES FOR THE COASTAL ZONES FOR THIS
EVENING...EXCEPT FOR THROUGH LATE TONIGHT OVER THE OUTER COASTAL
WATERS FROM 10 TO 60 NAUTICAL MILES OFFSHORE.

WEAKER PRESSURE GRADIENTS WILL GIVE LIGHTER FLOW ON WEDNESDAY. SMALL
CRAFT ADVISORIES MAY NEED TO BE CONTINUED OVER THE OUTER COASTAL
ZONES WITH SEAS CONTINUING TO BE AROUND 10 FEET. BAR CONDITIONS MAY
BECOME ROUGH AGAIN DURING THE EBB MIDDAY WEDNESDAY.

A COLD FRONT WILL APPROACH THE WATERS LATE THURSDAY AND THURSDAY
NIGHT. GALE FORCE WINDS ARE POSSIBLE WITH THIS FRONT...MAINLY OVER
THE COASTAL WATERS. A GALE WATCH HAS BEEN ISSUED FOR THE COAST 18Z
THU THROUGH 12Z FRI FOR THIS FRONT.

A STRONGER WARM FRONT ON SATURDAY COULD PRODUCES GALES OVER THE
NORTHERN INLAND WATERS...ENTRANCES TO THE STRAIT OF JUAN DE FUCA...
AND COASTAL WATERS.

A LONG FETCH OF STRONG WESTERLY FLOW IS NOW DEVELOPING OVER THE
NORTHWESTERN PACIFIC. WAVES BEING GENERATED IN THIS FETCH AREA WILL
MARCH ACROSS THE PACIFIC THIS WEEK AND WILL LIKELY REACH THE
WASHINGTON COAST AS AN ENERGETIC 20 TO 25 FT SWELL ON FRIDAY. LONG
PERIOD SWELL WITH THIS HEIGHT WOULD PRODUCE BEACH EROSION. ALBRECHT

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY COAST.

&&

$$

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML











000
FXUS66 KSEW 162348
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 PM PST TUE DEC 16 2014

.SYNOPSIS...A WEAK TROUGH WILL BRING SPOTTY LIGHT RAIN TO WESTERN
WASHINGTON THROUGH WEDNESDAY NIGHT. A STRONGER PACIFIC FRONTAL
SYSTEM IS FORECAST TO ARRIVE LATER THURSDAY INTO FRIDAY WITH MORE
WIDESPREAD RAIN. YET ANOTHER SYSTEM MAY BRING HEAVY RAIN AT TIMES TO
THE MOUNTAINS AND COAST SUNDAY INTO EARLY NEXT WEEK.
&&

.SHORT TERM...RADAR AND SATELLITE IMAGERY INDICATE CLOUDS AND SOME
SPOTTY LIGHT RAIN ACROSS WRN WA THIS AFTERNOON. THE UPPER LEVEL
TROUGH AXIS STILL OFFSHORE IS PROVIDING MOIST SLY FLOW OVER THE
AREA. DYNAMIC LIFT IS WEAK GIVEN THE SPLIT FLOW ALOFT AND WITH THE
SURFACE TROUGH. THEREFORE...MEASURABLE RAIN IS NOT VERY WIDESPREAD
AND IS MAINLY CONFINED TO THE S AND W OF PUGET SOUND. LIGHT
PRECIPITATION SHOULD EASE OFF OR END FOR A TIME THIS EVENING AS THE
BULK OF MOISTURE AND LIFT DIVES SE INTO CA/OREGON.

THE NRN BRANCH UPPER TROUGH AXIS MOVES THROUGH WRN WA LATER TONIGHT
AND WEDNESDAY. MODELS GENERALLY DEPICT WEAK LIFT AND ONLY LIGHT
SPOTTY QPF FIELDS OVER THE HIGHER TERRAIN OF WRN WA. HOWEVER...THE
21Z HRRR SHOWS MOISTURE FROM THE SRN STREAM SYSTEM BECOMING
ENTRAINED NWD AHEAD OF THE NRN BRANCH TROUGH LATE TONIGHT. THIS IS
DIFFERENT FROM THE GFS40 WHICH SHOWS A MORE PRONOUNCED SPLIT AND
MEAGER QPF FIELDS. SINCE MODELS HAVE NOT SETTLED ON THE DEGREE OF
SPLITTING...SOME CHANCE POPS WILL REMAIN IN THE FORECAST FOR WRN WA
THROUGH WEDNESDAY. THE TROUGH AXIS SHIFTS EWD WEDNESDAY NIGHT WITH
SHOWERS ENDING.

A WEAK RIDGE ALOFT IS STILL EXPECTED TO SHIFT ACROSS WA ON THURSDAY.
MODELS CONTINUE TO DIFFER ON THE TIMING OF THE NEXT SOMEWHAT
STRONGER SYSTEM TO ARRIVE. THE 18Z GFS/12Z ECMWF AND NAM12 SHOW RAIN
HOLDING OFF UNTIL LATE THURSDAY AFTERNOON. THIS IS SLOWER THAN SOME
PAST RUNS AND SLOWER THAN THE 12Z CANADIAN. A STRONG 180+ KT JET
ACROSS THE PACIFIC PUTS THE SLOWER TIMING INTO QUESTION AND WILL OPT
TO LEAVE A CHANCE OF RAIN IN THE FORECAST.

THE FRONT PUSHES THROUGH WRN WA THURSDAY NIGHT BUT WILL
SPLIT...THOUGH LATER THAN PREVIOUS SYSTEMS. QPF AMOUNTS SHOULD BE
MORE WIDESPREAD AND COULD APPROACH A HALF INCH IN THE MOUNTAINS.
SNOW LEVELS WILL BE LOWER THAN WITH PAST SYSTEMS SO A FEW INCHES
DOWN TO 4000 FEET IS POSSIBLE. HIGHER ELEVATIONS SUCH AS THE SKI
RESORTS COULD GET 6 INCHES IF THE SYSTEM DOES NOT SPLIT TOO
SEVERELY. LOWLAND RAIN WILL CHANGE OVER TO SHOWERS LATE FRIDAY OR
FRIDAY NIGHT AHEAD OF THE NEXT STORM SYSTEM.

.LONG TERM...GLOBAL MODELS REMAIN IN GOOD AGREEMENT THAT A MORE
CONSOLIDATED WLY FLOW PATTERN DEVELOPS ACROSS THE PACIFIC OVER THE
WEEKEND. THE STRONG WLY JET WILL DIRECT AN ATMOSPHERIC RIVER OF
MOISTURE INTO WRN WA LATER SATURDAY THROUGH  EARLY NEXT WEEK. THE
INITIAL WARM FRONTAL WAVE WILL BRING STRONG SW FLOW ALOFT AND HEAVY
RAIN TO THE MOUNTAINS SATURDAY AFTERNOON AND NIGHT. MODELS DIFFER ON
HOW LONG THE TRAILING MOISTURE PLUM REMAINS DIRECTED INTO WRN WA.
HOWEVER...MOST MODELS SHOW AT LEAST 24-36 HOURS OF HEAVY MOUNTAIN
RAINFALL BEFORE TAPERING OFF WHICH COULD CAUSE SOME CONCERNS FOR
FLOODING ON PRONE RIVERS. SEE THE HYDRO DISCUSSION FOR FURTHER
DETAILS. RAIN AMOUNTS WILL NOT BE NEARLY HAS HEAVY IN THE LOWLANDS
WHICH SHOULD SHADOW EFFICIENTLY FROM SEATTLE/TACOMA NORTH TO EVERETT
GIVEN THE STRONG W-WSW FLOW. HIGH POPS ARE STILL WARRANTED EVEN WITH
LESS QPF AND IT WILL ALSO BE BREEZY AT TIMES...ESPECIALLY ACROSS THE
N INTERIOR/COAST WHICH IS MORE SUSCEPTIBLE TO STRONG SE SURFACE
GRADIENTS.

THE GFS/ECMWF BOTH SHOW A LULL OR BREAK IN PRECIPITATION AROUND
MONDAY OR MONDAY NIGHT. ANOTHER SURFACE LOW FEATURE TRACKS INTO WRN
WA TUESDAY WITH MORE RAIN. IF THERE IS A BREAK AS SHOWN BY CURRENT
MODELS...THEN ADDITIONAL RAINFALL WILL PROBABLY NOT BE
HYDROLOGICALLY SIGNIFICANT. IF THE LOW IS FASTER WITH LITTLE OR NO
BREAK...THEN IT WILL ADD TO FLOODING CONCERNS.

RAIN TRANSITIONS TO SHOWERS SOMETIME MID WEEK. THE 00Z RUNS OF THE
GFS/ECMWF SHOWED A COLDER NLY FLOW PATTERN DEVELOPING. 12/18Z RUNS
ARE COOL AND DRY BY WEDNESDAY BUT NOT NEARLY AS COLD. IT WILL ALL
DEPEND ON THE DEVELOPMENT OF A HIGH OVER KONA LOW. RIDGING OUTSIDE
OF 140 W WOULD DRIVE COLDER NLY FLOW OVER THE PAC NW. INSIDE 140 W
WOULD STILL LIKELY BE DRY BUT NOT AS COLD. TEMPERATURES ARE TRENDED
DOWNWARD SLIGHTLY WITH HIGHS IN THE LOWER 40S BY WEDNESDAY AND LOWS
IN THE 30S. MERCER

&&

.HYDROLOGY...RIVER FLOODING IS NOT EXPECTED THROUGH SATURDAY. A
MOIST WESTERLY FLOW PATTERN WILL DEVELOP SATURDAY NIGHT THROUGH
EARLY NEXT WEEK. THE COMBINATION OF STRONG FLOW AND A LONG MOISTURE
FETCH MEANS HEAVY MOUNTAIN RAIN IS POSSIBLE IF THE FRONTAL SYSTEM IS
DIRECTED INTO WRN WA. MOST MODEL RUNS SHOW A POTENTIAL FOR 3-6+
INCHES OF RAIN IN 36 HOURS FROM SATURDAY NIGHT THROUGH EARLY MONDAY.
THIS IS POSSIBLY ENOUGH TO CAUSE FLOODING ON SOME OF THE MORE FLOOD
PRONE RIVERS. THE EXTENDED FORECAST SHOULD BE MONITORED CLOSELY. AN
EXTENDED FLOOD OUTLOOK WILL BE ISSUED IF FLOODING BECOMES MORE
CERTAIN.  MERCER

&&

.AVIATION...AN UPPER LEVEL TROUGH OVER THE COASTAL WATERS COMBINED
WITH HIGH PRESSURE WELL EAST OF THE AREA IS GIVING LIGHT SOUTHERLY
FLOW ALOFT. AT THE SURFACE...HIGH PRESSURE EAST OF THE CASCADES
COMBINED WITH A TROUGH OF LOW PRESSURE OFFSHORE IS GIVING LOW LEVEL
OFFSHORE FLOW. THE TROUGH WILL MOVE INLAND ON WEDNESDAY. THE AIR
MASS IS MOIST AND STABLE...EXCEPT IS DRY AT LOW LEVELS OVER THE
INTERIOR VALLEYS. THE AIR MASS WILL BECOME DRIER TONIGHT THROUGH
WEDNESDAY.

DESPITE ABUNDANT CLOUD COVER AND LIGHT PRECIPITATION...LOW LEVEL
OFFSHORE FLOW IS GIVING VFR CONDITIONS TO THE INTERIOR OF WESTERN
WASHINGTON WITH GOOD VISIBILITY AND CEILINGS AROUND FLIGHT LEVEL
035. MARGINAL VFR CEILINGS AND VISIBILITIES ARE OCCURRING ON THE
NORTH COAST AND LOCAL CEILINGS AROUND FLIGHT LEVEL 010-015 ARE BEING
OBSERVED AROUND KOLM. THE LATEST NAM12 AND GFS SOLUTIONS SUGGEST
THAT THE LOWER AND MID LEVELS OF THE AIR MASS WILL DRY TONIGHT AS
THE WEAK TROUGH THAT IS IN THE COASTAL WATERS MOVES ONSHORE. ANY
CLEARING MAY RESULT IN LOCAL IFR CEILINGS AND VISIBILITIES IN
STRATUS AND FOG LATE TONIGHT INTO WED MORNING...ESPECIALLY IN FOG
PRONE VALLEYS SUCH AS AT KOLM. THE LATEST HRRR SHOWS PRECIPITATION
TO THE NE OF A LOW MOVING IN AROUND THE EXTREME SOUTH OREGON COAST
WILL SHOOT NE INTO THE AREA OVERNIGHT. WILL MONITOR SATELLITE AND
RADAR FOR THIS POSSIBILITY...BUT THE INCREASING RAIN SCENARIO
APPEARS UNLIKELY AT THIS TIME GIVEN THE STRENGTH OF THE SPLIT FLOW
ALONG THE WEST COAST. AT THIS TIME THE 00Z TERMINALS WILL FOLLOW THE
NAM12/GFS SCENARIO AND WILL BE SIMILAR TO THE PREVIOUS PACKAGE.
ALBRECHT

KSEA...VFR CONDITIONS WILL CONTINUE WITH BKN-OVC035 OVC060...
PERIODS OF VERY LIGHT RAIN AND VISIBILITIES 6KM OR HIGHER. CEILINGS
ARE EXPECTED TO IMPROVE AND RAIN CHANCES DECREASE ABOUT 04Z THIS
EVENING. EXPECT EAST WINDS 6 TO 9 KT TONIGHT. ALBRECHT

&&

.MARINE...HIGH PRESSURE EAST OF THE CASCADES COMBINED WITH A TROUGH
OF LOW PRESSURE OVER THE COASTAL WATERS IS GIVING LIGHT OFFSHORE
FLOW TO THE AREA. THIS OFFSHORE FLOW WILL CONTINUE TO GRADUALLY EASE
OVERNIGHT AS THE TROUGH SLOWLY MOVES TOWARD THE COASTLINE. A SMALL
CRAFT ADVISORY CONTINUES FOR THE COASTAL ZONES FOR THIS
EVENING...EXCEPT FOR THROUGH LATE TONIGHT OVER THE OUTER COASTAL
WATERS FROM 10 TO 60 NAUTICAL MILES OFFSHORE.

WEAKER PRESSURE GRADIENTS WILL GIVE LIGHTER FLOW ON WEDNESDAY. SMALL
CRAFT ADVISORIES MAY NEED TO BE CONTINUED OVER THE OUTER COASTAL
ZONES WITH SEAS CONTINUING TO BE AROUND 10 FEET. BAR CONDITIONS MAY
BECOME ROUGH AGAIN DURING THE EBB MIDDAY WEDNESDAY.

A COLD FRONT WILL APPROACH THE WATERS LATE THURSDAY AND THURSDAY
NIGHT. GALE FORCE WINDS ARE POSSIBLE WITH THIS FRONT...MAINLY OVER
THE COASTAL WATERS. A GALE WATCH HAS BEEN ISSUED FOR THE COAST 18Z
THU THROUGH 12Z FRI FOR THIS FRONT.

A STRONGER WARM FRONT ON SATURDAY COULD PRODUCES GALES OVER THE
NORTHERN INLAND WATERS...ENTRANCES TO THE STRAIT OF JUAN DE FUCA...
AND COASTAL WATERS.

A LONG FETCH OF STRONG WESTERLY FLOW IS NOW DEVELOPING OVER THE
NORTHWESTERN PACIFIC. WAVES BEING GENERATED IN THIS FETCH AREA WILL
MARCH ACROSS THE PACIFIC THIS WEEK AND WILL LIKELY REACH THE
WASHINGTON COAST AS AN ENERGETIC 20 TO 25 FT SWELL ON FRIDAY. LONG
PERIOD SWELL WITH THIS HEIGHT WOULD PRODUCE BEACH EROSION. ALBRECHT

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY COAST.

&&

$$

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML












000
FXUS66 KOTX 162243
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
242 PM PST TUE DEC 16 2014

.SYNOPSIS...
A more active weather pattern will develop through the week with
periods of light snow in the mountains...and rain or snow in the
valleys. Lower elevations from Interstate 90 south will see mainly
rain...while areas in the Cascades and near the Canadian border
will remain mainly snow. A much stronger weather system over the
weekend will usher in warmer temperatures with sharply rising snow
levels...as well as the potential for windy conditions.

&&

.DISCUSSION...

Tonight into Tomorrow...Forecast remains fairly cluttered with
pops of widely varying value yet the precipitation amounts remain
on the low side going into tomorrow. They remain assigned to the
extreme north and within the vicinity of the East Slopes of the
North Cascades and Northern Mountains with a weak exiting weather
disturbance. A second disturbance noted with a cluster of moderate
to high pops passes within close proximity to the West Plains of
Spokane, Eastern Lincoln, Northeast Adams, and Northwest Whitman
Counties and by 3Z its should be up in the northern mountains and
weakened considerably. Amounts of rain or snow expected to fall
out of this small circulation are on the light side on the order
of .05 liquid or less. After these features leave the area fog and
low clouds should fill back in just in time to be overrun in a
somewhat similar fashion with yet another weak upper level
disturbance passage tomorrow. Given this fairly stagnant pattern
is lacking any substantial amount of either cold dry air or snow-
cover the forecast temperatures remain on the warm side of what
would be considered normal for this time of year. /Pelatti

Wednesday night through Saturday...A gradually more active pattern
will evolve for the middle to end of the week.

A weak short wave trough will track across Eastern Washington and
North Idaho Wednesday night into Thursday morning. This combined
with upslope flow into Northeast Washington and the Idaho
Panhandle will yield light snow accumulations mainly above 2500
feet per forecast soundings.

The next system enters Thursday night into Friday in the form of a
weak cold front. Cloud cover looks to thicken early Thursday
evening which will limit radiational cooling potential. There are
some minor differences regarding the lower level thermal profiles
from the NAM, GFS, and ECMWF...with the NAM and ECMWF the warmest.
Given a continued modification of the low level air mass through
Thursday with weak systems passing through...and lack of
radiational cooling potential Thu night...forecast leans towards
the warmer high resolution NAM/ECMWF models. However even if the
cooler GFS verifies the best potential for accumulations would be
north of Interstate 90...with Spokane/Coeur D`Alene likely seeing
a non-accumulating wet snow. Models suggest the potential for
light snow accumulations in the Cascades, Okanogan Highlands,
Waterville Plateau, Wenatchee area above 1000-1500 feet...northern
valleys above 2000-2500 feet...and in the mountains.

After a brief break Friday night...a much wetter system approaches
for the weekend. GFS and ECMWF show precip developing over
Central Washington Saturday afternoon as a warm front approaches.
Thermal profiles suggest mainly snow north and west of Moses
Lake...and mainly rain from Interstate 90 south Saturday
afternoon. JW

...A VERY WET WARM AND WINDY SYSTEM IS EXPECTED SATURDAY NIGHT
THROUGH MONDAY...

Saturday night through Monday...Model guidance is still remaining
quite consistent on bringing a strong storm into the region
during this period. This storm is currently just heading east of
Japan and looks fairly impressive on water vapor imagery. By the
time it nears the western US...it flattens our currently elongated
trough pattern and brings in very energetic zonal or westerly
flow. The upper level jet stream associated with this zonal flow
is still forecast to near 150 kts which will help advect ample
moisture into the region via a large atmospheric river. Model
guidance also remains very consistent on showing the leading edge
of the river on the coast by late Saturday afternoon and bringing
it across the Cascades overnight. This means we will see
widespread precipitation beginning sometime Saturday night and
continuing through most of Sunday. Given that the precipitation
will be largely derived from swift westerly flow in the 850-700 mb
layer we should see a rapid ending of the precipitation in the lee
of the Cascades sometime on Sunday as the strong warm air
advection in that layer turns to neutral or weak cold air
advection. The main story then will turn to wind and warm
temperatures. Before that occurs though...we expect all locations
to see some precipitation...much of which will be heavy along the
Cascade crest and likely over the Idaho Panhandle. 24 hr
precipitation amounts between Saturday night and Sunday night will
likely range from 1-2.5 inches along much of the crest to
0.75-1.50 inches over the Panhandle. Meanwhile amounts will be
substantially lower over the areas in between given the swift
westerly flow. Despite these lofty precipitation amounts...most
will fall as rain as snow levels will initially begin near the
valleys floors in the Cascades rising to nearly 4-6k feet by
Sunday along the Canadian border and much higher near the Oregon
border. So this is not expected to be a good snow event. During
the rising snow level period...we could also see a brief period of
freezing rain near the Cascades, especially south of Lake Chelan.
The threat of precipitation will gradually wind down across the
region on Monday as the atmospheric river begins to sag south of
the forecast area.

So as the precipitation threat eases over most of Washington between
the Cascades and Idaho Panhandle mountains we anticipate a very
warm and breezy period. The UW MM5 model is showing sustained
surface winds of 25-30 mph so we`d expect the possibility of gusts
from 40-50 mph if the models hold to this notion. Meanwhile
temperatures will surge to levels much warmer than normal for this
time of year. Widespread temperatures in the 40s to mid 50s can be
expected so any snow which falls through the end of this week
would certainly melt. This weather pattern will somewhat similar
to what t we encountered just about a week ago on the tenth and
eleventh, just perhaps not quite as warm. Winds will also be a
little more widespread.

Monday night and Tuesday...The atmospheric river is expected to be
well south of the forecast however there will be enough moisture
left behind to keep some orographic precipitation left in the
forecast. Again most will occur near the Cascades and perhaps the
southern half of the Idaho Panhandle. Temperatures will begin to
cool down somewhat as the upper level jet sags atop the region
allowing slightly cooler air to move into the region. By this
point snow levels will be sufficiently low to bring snow to
elevations between 3-4k feet. Amounts should not be terribly heavy
however. fx


&&

.AVIATION...
18Z TAFS: Weak upper level disturbance working its way through the
aviation area this morning. A second weak disturbance that is
smaller is followiong quickly behind and will pass today as well.
So for the most part the precipitation is expect to be rather
light and produce and/or enhance ongoing MVFR ceilings and
visibilites today...but locations nearest very localized higher
intensity precipitation could dip to VFR at times. Overnight the
expecation is these two disturbances will have cleared the area
and fog/low clouds will continue to be an issue. /Pelatti




&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        29  38  33  36  33  38 /  50  30  40  30  20  70
Coeur d`Alene  30  40  33  37  31  38 /  30  30  50  50  20  70
Pullman        29  42  34  42  33  41 /  30  10  50  30  20  70
Lewiston       32  42  35  45  34  43 /  10  10  40  30  10  50
Colville       28  36  33  37  33  37 /  40  30  40  30  50  70
Sandpoint      28  36  33  37  30  36 /  20  30  60  60  20  80
Kellogg        30  38  32  38  29  37 /  20  10  70  60  20  70
Moses Lake     28  38  29  38  34  41 /  10  30  20  10  60  50
Wenatchee      31  37  30  37  33  40 /  60  30  30  10  60  50
Omak           26  34  28  34  32  37 /  60  40  40  10  70  60

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 162243
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
242 PM PST TUE DEC 16 2014

.SYNOPSIS...
A more active weather pattern will develop through the week with
periods of light snow in the mountains...and rain or snow in the
valleys. Lower elevations from Interstate 90 south will see mainly
rain...while areas in the Cascades and near the Canadian border
will remain mainly snow. A much stronger weather system over the
weekend will usher in warmer temperatures with sharply rising snow
levels...as well as the potential for windy conditions.

&&

.DISCUSSION...

Tonight into Tomorrow...Forecast remains fairly cluttered with
pops of widely varying value yet the precipitation amounts remain
on the low side going into tomorrow. They remain assigned to the
extreme north and within the vicinity of the East Slopes of the
North Cascades and Northern Mountains with a weak exiting weather
disturbance. A second disturbance noted with a cluster of moderate
to high pops passes within close proximity to the West Plains of
Spokane, Eastern Lincoln, Northeast Adams, and Northwest Whitman
Counties and by 3Z its should be up in the northern mountains and
weakened considerably. Amounts of rain or snow expected to fall
out of this small circulation are on the light side on the order
of .05 liquid or less. After these features leave the area fog and
low clouds should fill back in just in time to be overrun in a
somewhat similar fashion with yet another weak upper level
disturbance passage tomorrow. Given this fairly stagnant pattern
is lacking any substantial amount of either cold dry air or snow-
cover the forecast temperatures remain on the warm side of what
would be considered normal for this time of year. /Pelatti

Wednesday night through Saturday...A gradually more active pattern
will evolve for the middle to end of the week.

A weak short wave trough will track across Eastern Washington and
North Idaho Wednesday night into Thursday morning. This combined
with upslope flow into Northeast Washington and the Idaho
Panhandle will yield light snow accumulations mainly above 2500
feet per forecast soundings.

The next system enters Thursday night into Friday in the form of a
weak cold front. Cloud cover looks to thicken early Thursday
evening which will limit radiational cooling potential. There are
some minor differences regarding the lower level thermal profiles
from the NAM, GFS, and ECMWF...with the NAM and ECMWF the warmest.
Given a continued modification of the low level air mass through
Thursday with weak systems passing through...and lack of
radiational cooling potential Thu night...forecast leans towards
the warmer high resolution NAM/ECMWF models. However even if the
cooler GFS verifies the best potential for accumulations would be
north of Interstate 90...with Spokane/Coeur D`Alene likely seeing
a non-accumulating wet snow. Models suggest the potential for
light snow accumulations in the Cascades, Okanogan Highlands,
Waterville Plateau, Wenatchee area above 1000-1500 feet...northern
valleys above 2000-2500 feet...and in the mountains.

After a brief break Friday night...a much wetter system approaches
for the weekend. GFS and ECMWF show precip developing over
Central Washington Saturday afternoon as a warm front approaches.
Thermal profiles suggest mainly snow north and west of Moses
Lake...and mainly rain from Interstate 90 south Saturday
afternoon. JW

...A VERY WET WARM AND WINDY SYSTEM IS EXPECTED SATURDAY NIGHT
THROUGH MONDAY...

Saturday night through Monday...Model guidance is still remaining
quite consistent on bringing a strong storm into the region
during this period. This storm is currently just heading east of
Japan and looks fairly impressive on water vapor imagery. By the
time it nears the western US...it flattens our currently elongated
trough pattern and brings in very energetic zonal or westerly
flow. The upper level jet stream associated with this zonal flow
is still forecast to near 150 kts which will help advect ample
moisture into the region via a large atmospheric river. Model
guidance also remains very consistent on showing the leading edge
of the river on the coast by late Saturday afternoon and bringing
it across the Cascades overnight. This means we will see
widespread precipitation beginning sometime Saturday night and
continuing through most of Sunday. Given that the precipitation
will be largely derived from swift westerly flow in the 850-700 mb
layer we should see a rapid ending of the precipitation in the lee
of the Cascades sometime on Sunday as the strong warm air
advection in that layer turns to neutral or weak cold air
advection. The main story then will turn to wind and warm
temperatures. Before that occurs though...we expect all locations
to see some precipitation...much of which will be heavy along the
Cascade crest and likely over the Idaho Panhandle. 24 hr
precipitation amounts between Saturday night and Sunday night will
likely range from 1-2.5 inches along much of the crest to
0.75-1.50 inches over the Panhandle. Meanwhile amounts will be
substantially lower over the areas in between given the swift
westerly flow. Despite these lofty precipitation amounts...most
will fall as rain as snow levels will initially begin near the
valleys floors in the Cascades rising to nearly 4-6k feet by
Sunday along the Canadian border and much higher near the Oregon
border. So this is not expected to be a good snow event. During
the rising snow level period...we could also see a brief period of
freezing rain near the Cascades, especially south of Lake Chelan.
The threat of precipitation will gradually wind down across the
region on Monday as the atmospheric river begins to sag south of
the forecast area.

So as the precipitation threat eases over most of Washington between
the Cascades and Idaho Panhandle mountains we anticipate a very
warm and breezy period. The UW MM5 model is showing sustained
surface winds of 25-30 mph so we`d expect the possibility of gusts
from 40-50 mph if the models hold to this notion. Meanwhile
temperatures will surge to levels much warmer than normal for this
time of year. Widespread temperatures in the 40s to mid 50s can be
expected so any snow which falls through the end of this week
would certainly melt. This weather pattern will somewhat similar
to what t we encountered just about a week ago on the tenth and
eleventh, just perhaps not quite as warm. Winds will also be a
little more widespread.

Monday night and Tuesday...The atmospheric river is expected to be
well south of the forecast however there will be enough moisture
left behind to keep some orographic precipitation left in the
forecast. Again most will occur near the Cascades and perhaps the
southern half of the Idaho Panhandle. Temperatures will begin to
cool down somewhat as the upper level jet sags atop the region
allowing slightly cooler air to move into the region. By this
point snow levels will be sufficiently low to bring snow to
elevations between 3-4k feet. Amounts should not be terribly heavy
however. fx


&&

.AVIATION...
18Z TAFS: Weak upper level disturbance working its way through the
aviation area this morning. A second weak disturbance that is
smaller is followiong quickly behind and will pass today as well.
So for the most part the precipitation is expect to be rather
light and produce and/or enhance ongoing MVFR ceilings and
visibilites today...but locations nearest very localized higher
intensity precipitation could dip to VFR at times. Overnight the
expecation is these two disturbances will have cleared the area
and fog/low clouds will continue to be an issue. /Pelatti




&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        29  38  33  36  33  38 /  50  30  40  30  20  70
Coeur d`Alene  30  40  33  37  31  38 /  30  30  50  50  20  70
Pullman        29  42  34  42  33  41 /  30  10  50  30  20  70
Lewiston       32  42  35  45  34  43 /  10  10  40  30  10  50
Colville       28  36  33  37  33  37 /  40  30  40  30  50  70
Sandpoint      28  36  33  37  30  36 /  20  30  60  60  20  80
Kellogg        30  38  32  38  29  37 /  20  10  70  60  20  70
Moses Lake     28  38  29  38  34  41 /  10  30  20  10  60  50
Wenatchee      31  37  30  37  33  40 /  60  30  30  10  60  50
Omak           26  34  28  34  32  37 /  60  40  40  10  70  60

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$




000
FXUS66 KPQR 162231
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
231 PM PST TUE DEC 16 2014

.SYNOPSIS...THERE WILL BE A BREAK IN RAIN THIS AFTERNOON BEFORE RAIN
ASSOCIATED WITH A LOW WEST OF THE CENTRAL OREGON COAST...MOVES SOUTH
TO NORTH THIS EVENING THROUGH WEDNESDAY MORNING. SHOWERS WILL
PRIMARILY BE OVER THE HIGHER TERRAIN. AN UPPER TROUGH WILL MAINTAIN A
CHANCE FOR SHOWERS THROUGH WEDNESDAY EVENING. A MORE ORGANIZED FRONT
WILL BRING GUSTY WINDS AND LARGE SURF TO THE COAST...WITH  RAIN
SPREADING INLAND THURSDAY NIGHT AND FRIDAY. RISING SNOW LEVELS WILL
LIMIT SNOW TO THE HIGHEST PEAKS...BUT COLDER AIR BEHIND THE FRONT MAY
RESULT IN SOME SNOW SHOWERS FOR THE CASCADES PASSES FRIDAY EVENING
AND SATURDAY. A WARMER AND MOISTER WEATHER IS EXPECTED THIS WEEKEND.

&&

.SHORT TERM...TONIGHT THROUGH FRIDAY...SHOWERS HAVE PRETTY MUCH ENDED
OVER THE PORTLAND FORECAST AREA EARLY THIS AFTERNOON...EXCEPT FOR
VERY INFREQUENT ISOLATED SHOWER OVER THE SW WASHINGTON CASCADES.
SATELLITE IMAGERY SHOWS A SURFACE LOW AROUND 150 MILES WEST OF THE
SOUTHERN OREGON COAST...NEAR 42N 127W. THE HIGHER RESOLUTION
MODELS...HRRR AND RAP INITIALIZE BEST WITH THE LOW AND FORECAST RAIN
MOVING NORTH INTO LANE COUNTY SLIGHTLY EARLIER THAN THE OTHER MODELS.
HAVE TRENDED TOWARDS THIS EARLIER ARRIVAL...BUT ONLY HAVE FAIR
CONFIDENCE THAT THE TIMING WILL PAN OUT. ANY RAIN LATE THIS AFTERNOON
SHOULD BE FAIRLY LIGHT AND REMAIN WEST OF THE SOUTH AND CENTRAL
WILLAMETTE VALLEY.

THE LOW WILL MOVE CLOSER TO THE SOUTHERN OREGON COAST LATE THIS
AFTERNOON AND EVENING THEN MOVE ONTO THE CENTRAL OREGON COAST AS AN
UPPER TROUGH LATE TONIGHT...WITH SHOWERS MAINLY OVER THE HIGHER
TERRAIN THROUGH WEDNESDAY MORNING. SOME CLEARING EARLY WED MORNING
MAY RESULT IN SHALLOW FOG AND LOW CLOUDS IN SOME OF THE INTERIOR
VALLEYS...MAINLY SOUTH OF SALEM.

EASTERLY WINDS HAVE HELD ON TODAY WITH A TROUTDALE TO DALLES PRESSURE
GRADIENT HOLDING AROUND 5 MB. THIS GRADIENT SHOULD TIGHTEN A LITTLE
THIS EVENING AS THE LOW MOVES CLOSER TO THE COAST AND MAINTAIN GUSTS
AROUND 30 MPH THROUGH THE WESTERN COLUMBIA RIVER GORGE.

SHOWERS WILL CONTINUE WEDNESDAY...MAINLY FOR THE HIGHER TERRAIN AS
THE PARENT UPPER LEVEL TROUGH MOVES OVER THE PACIFIC NW. SHOWERS
SHOULD END OVERNIGHT AS AN UPPER RIDGE BUILDS OVER THE AREA AND
EXPECT THAT CLEARING SKIES AND LIGHT WINDS WILL LEAD TO SHALLOW FOG
FOR THE INTERIOR VALLEYS EARLY THURSDAY MORNING. MOST OF THURSDAY
WILL BE DRY WITH AN INCREASE OF MID AN HIGH LEVEL CLOUDS IN THE
AFTERNOON.

MODELS ARE IN GOOD AGREEMENT THAT A WELL ORGANIZED FRONT WILL BRING
GUSTY WINDS TO THE COAST THURSDAY EVENING WITH RAIN SPREADING INLAND
THURSDAY NIGHT AND FRIDAY. PRECIPITABLE WATER IS EXPECTED TO BE NEAR
AN INCH AND AN APPROACHING JET STREAK SHOULD PROVIDE GOOD LIFT AND
EXPECT THE HIGHEST RAINFALL TOTALS OF 0.75 TO 1 INCH ACROSS THE
COAST AND COAST RANGE THURSDAY NIGHT THROUGH FRIDAY MORNING. OTHER
AREAS SHOULD SEE BETWEEN 0.4 AND 0.60 INCH OF RAIN. SNOW LEVELS
SHOULD REMAIN ABOVE 5000 FEET DURING THE PEAK RAIN PERIOD...BUT LOWER
TO NEAR OR BELOW THE CASCADE PASSES BEHIND THE FRONT FRIDAY
AFTERNOON.

.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY...A BROAD RIDGE OF HIGH
PRESSURE OVER THE WESTERN U.S. FLATTENS AS A STRONG LOW PRESSURE
SYSTEM OVER THE GULF OF ALASKA MOVES INLAND TO OUR NORTH. AS THIS
TROUGH MOVES ON SHORE SATURDAY...THE ASSOCIATED COLD FRONT MOVES
ONSHORE AND STALLS EAST-TO-WEST ACROSS NORTHWEST OREGON AND
SOUTHWEST WASHINGTON. THIS PUTS OUR AREA IN THE PATH OF RAIN
STARTING SATURDAY THROUGH MONDAY. SOME UNCERTAINTY EXISTS IN WHERE
THIS BOUNDARY WILL SET UP...WHICH WILL DETERMINE HOW MUCH RAINFALL
WE WILL GET. ON TUESDAY...GEFS ENSEMBLE SPAGHETTI PLOTS GET MESSY
AND SIGNIFICANT DIFFERENCES START TO SHOW UP BETWEEN THE GFS AND
ECMWF...DECREASING CONFIDENCE ON HOW THE REST OF THE WEEK WILL SHAPE
UP.  AS OF NOW...THE MOST COMMON SOLUTION IS THAT HIGH PRESSURE
RIDGING WILL START TO BUILD BACK OVER THE WESTERN U.S. WHICH
SUGGESTS DRIER WEATHER STARTING TUESDAY...THOUGH UNCERTAINTY IS VERY
HIGH. -MCCOY

&&

.AVIATION...MAINLY VFR CONDITIONS ACROSS THE FORECAST AREA THIS
AFTERNOON...WITH A COUPLE NOTABLE EXCEPTIONS. IFR/LIFR CIGS
DEVELOPED THIS MORNING IN THE WILLAMETTE VALLEY KSLE SOUTHWARD...
AND HAVE LINGERED ALL DAY DUE TO LIGHT N-NE FLOW JAMMING THE LOW
CLOUDS AGAINST THE SOUTH END OF THE WILLAMETTE VALLEY. KSLE
APPEARS TO BE ON THE NORTHERN FRINGE OF THESE LOW CLOUDS...AND
WILL LIKELY REMAIN SO THROUGH THIS EVENING. CIGS WILL PROBABLY
DROP BACK DOWN TO NEAR THE DECK IN THESE AREAS TONIGHT AS -RA
DEVELOPS WITH OUR NEXT FRONTAL SYSTEM AND MOISTENS UP THE LOW
LEVEL AIR MASS.

ALSO EASTERLY UPSLOPE FLOW CAUSING MOUNTAIN OBSCURATIONS ALONG
THE EAST SLOPES AND CREST OF THE CASCADES...AND WILL LIKELY
CONTINUE TO DO SO OVERNIGHT TONIGHT.

WILL SEE AREAS -RA SPREAD NORTHWARD ACROSS MUCH OF THE FORECAST
AREA LATER TONIGHT...BUT IT APPEARS CIGS WILL GENERALLY REMAIN VFR
UNLESS OTHERWISE STATED ABOVE.WEAGLE

KPDX AND APPROACHES...VFR CIGS LIKELY REMAIN AT OR ABOVE 5 K FT
THROUGH THIS EVENING. SOME -RA IS POSSIBLE LATER TONIGHT AS
MOISTURE ASSOCIATED WITH AN OCCLUDED FRONT SPREADS NORTHWARD.
HOWEVER IT APPEARS CIGS SHOULD REMAIN VFR. LIGHT TO MODERATE
EASTERLY SFC WINDS THROUGH THIS EVENING.  WEAGLE

&&

.MARINE...VISIBLE SATELLITE IMAGERY SHOWS A WELL-DEFINED LOW
PRESSURE SYSTEM ABOUT 150 NM WEST OF CRESCENT CITY CA. THIS SYSTEM
APPEARS TO HAVE REACHED ITS MAXIMUM STRENGTH WITH A CENTRAL
PRESSURE AROUND 995 MB. FORECAST MODELS APPEAR TO HAVE GENERALLY
CAUGHT UP WITH THE STRENGTH OF THIS SYSTEM AFTER LAGGING BEHIND
EARLIER TODAY. THE LOW WILL DRIFT E-NE TONIGHT...PUSHING INTO WRN
OREGON BY WED. IT APPEARS E-NE WINDS CURLING AROUND THIS LOW WILL
BE ENOUGH TO PUSH GUSTS TO 25 KT IN OUR FAR SW WATERS...SO ISSUED
A SCA FOR WINDS IN THIS AREA THIS EVENING. AS THE LOW WEAKENS...
WINDS ASSOCIATED WITH THIS SYSTEM SHOULD WEAKEN AS WELL.

THE NEXT RELATIVELY STRONG FRONTAL SYSTEM IS BEGINNING TO TAKE
SHAPE BETWEEN 160W-170W...AND MAY PRODUCE GALES FOR OUR WATERS AS
IT MOVES ONSHORE LATER THU/EARLY FRI. THERE IS A GOOD POTENTIAL
FOR COASTAL JET FORMATION WHICH WOULD ENHANCE WINDS JUST AHEAD OF
THE FRONT WITH GUSTS TO 45 KT POSSIBLE NEAR THE COAST THU NIGHT.
AFTER COORDINATION WITH WFO SEATTLE...DECIDED CONFIDENCE WAS HIGH
ENOUGH TO WARRANT A GALE WATCH FOR THIS SYSTEM. 12Z ECMWF/GFS SHOW
THIS SYSTEM TAKING A NEAR-IDEAL TRACK AND SPEED FOR DYNAMIC
FETCH...AND THIS SHOWS IN THE WAVE MODELS. ENP GUIDANCE SUGGESTS
A SOLID 17-21 FT SWELL WITH A DOMINANT PERIOD OF 16-20 SECONDS
FOLLOWS THE FRONT...PROBABLY ENOUGH TO WARRANT A HIGH SURF
ADVISORY FRIDAY.  WEAGLE

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...GALE WATCH FROM THURSDAY MORNING THROUGH THURSDAY EVENING FOR
     COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR WINDS FROM 6 PM THIS EVENING TO
     MIDNIGHT PST TONIGHT FOR WATERS FROM CASCADE HEAD TO
     FLORENCE OR FROM 10 TO 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 11 PM
     THIS EVENING TO 3 AM PST WEDNESDAY.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 9 AM TO
     5 PM PST WEDNESDAY.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.



000
FXUS66 KPQR 162231
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
231 PM PST TUE DEC 16 2014

.SYNOPSIS...THERE WILL BE A BREAK IN RAIN THIS AFTERNOON BEFORE RAIN
ASSOCIATED WITH A LOW WEST OF THE CENTRAL OREGON COAST...MOVES SOUTH
TO NORTH THIS EVENING THROUGH WEDNESDAY MORNING. SHOWERS WILL
PRIMARILY BE OVER THE HIGHER TERRAIN. AN UPPER TROUGH WILL MAINTAIN A
CHANCE FOR SHOWERS THROUGH WEDNESDAY EVENING. A MORE ORGANIZED FRONT
WILL BRING GUSTY WINDS AND LARGE SURF TO THE COAST...WITH  RAIN
SPREADING INLAND THURSDAY NIGHT AND FRIDAY. RISING SNOW LEVELS WILL
LIMIT SNOW TO THE HIGHEST PEAKS...BUT COLDER AIR BEHIND THE FRONT MAY
RESULT IN SOME SNOW SHOWERS FOR THE CASCADES PASSES FRIDAY EVENING
AND SATURDAY. A WARMER AND MOISTER WEATHER IS EXPECTED THIS WEEKEND.

&&

.SHORT TERM...TONIGHT THROUGH FRIDAY...SHOWERS HAVE PRETTY MUCH ENDED
OVER THE PORTLAND FORECAST AREA EARLY THIS AFTERNOON...EXCEPT FOR
VERY INFREQUENT ISOLATED SHOWER OVER THE SW WASHINGTON CASCADES.
SATELLITE IMAGERY SHOWS A SURFACE LOW AROUND 150 MILES WEST OF THE
SOUTHERN OREGON COAST...NEAR 42N 127W. THE HIGHER RESOLUTION
MODELS...HRRR AND RAP INITIALIZE BEST WITH THE LOW AND FORECAST RAIN
MOVING NORTH INTO LANE COUNTY SLIGHTLY EARLIER THAN THE OTHER MODELS.
HAVE TRENDED TOWARDS THIS EARLIER ARRIVAL...BUT ONLY HAVE FAIR
CONFIDENCE THAT THE TIMING WILL PAN OUT. ANY RAIN LATE THIS AFTERNOON
SHOULD BE FAIRLY LIGHT AND REMAIN WEST OF THE SOUTH AND CENTRAL
WILLAMETTE VALLEY.

THE LOW WILL MOVE CLOSER TO THE SOUTHERN OREGON COAST LATE THIS
AFTERNOON AND EVENING THEN MOVE ONTO THE CENTRAL OREGON COAST AS AN
UPPER TROUGH LATE TONIGHT...WITH SHOWERS MAINLY OVER THE HIGHER
TERRAIN THROUGH WEDNESDAY MORNING. SOME CLEARING EARLY WED MORNING
MAY RESULT IN SHALLOW FOG AND LOW CLOUDS IN SOME OF THE INTERIOR
VALLEYS...MAINLY SOUTH OF SALEM.

EASTERLY WINDS HAVE HELD ON TODAY WITH A TROUTDALE TO DALLES PRESSURE
GRADIENT HOLDING AROUND 5 MB. THIS GRADIENT SHOULD TIGHTEN A LITTLE
THIS EVENING AS THE LOW MOVES CLOSER TO THE COAST AND MAINTAIN GUSTS
AROUND 30 MPH THROUGH THE WESTERN COLUMBIA RIVER GORGE.

SHOWERS WILL CONTINUE WEDNESDAY...MAINLY FOR THE HIGHER TERRAIN AS
THE PARENT UPPER LEVEL TROUGH MOVES OVER THE PACIFIC NW. SHOWERS
SHOULD END OVERNIGHT AS AN UPPER RIDGE BUILDS OVER THE AREA AND
EXPECT THAT CLEARING SKIES AND LIGHT WINDS WILL LEAD TO SHALLOW FOG
FOR THE INTERIOR VALLEYS EARLY THURSDAY MORNING. MOST OF THURSDAY
WILL BE DRY WITH AN INCREASE OF MID AN HIGH LEVEL CLOUDS IN THE
AFTERNOON.

MODELS ARE IN GOOD AGREEMENT THAT A WELL ORGANIZED FRONT WILL BRING
GUSTY WINDS TO THE COAST THURSDAY EVENING WITH RAIN SPREADING INLAND
THURSDAY NIGHT AND FRIDAY. PRECIPITABLE WATER IS EXPECTED TO BE NEAR
AN INCH AND AN APPROACHING JET STREAK SHOULD PROVIDE GOOD LIFT AND
EXPECT THE HIGHEST RAINFALL TOTALS OF 0.75 TO 1 INCH ACROSS THE
COAST AND COAST RANGE THURSDAY NIGHT THROUGH FRIDAY MORNING. OTHER
AREAS SHOULD SEE BETWEEN 0.4 AND 0.60 INCH OF RAIN. SNOW LEVELS
SHOULD REMAIN ABOVE 5000 FEET DURING THE PEAK RAIN PERIOD...BUT LOWER
TO NEAR OR BELOW THE CASCADE PASSES BEHIND THE FRONT FRIDAY
AFTERNOON.

.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY...A BROAD RIDGE OF HIGH
PRESSURE OVER THE WESTERN U.S. FLATTENS AS A STRONG LOW PRESSURE
SYSTEM OVER THE GULF OF ALASKA MOVES INLAND TO OUR NORTH. AS THIS
TROUGH MOVES ON SHORE SATURDAY...THE ASSOCIATED COLD FRONT MOVES
ONSHORE AND STALLS EAST-TO-WEST ACROSS NORTHWEST OREGON AND
SOUTHWEST WASHINGTON. THIS PUTS OUR AREA IN THE PATH OF RAIN
STARTING SATURDAY THROUGH MONDAY. SOME UNCERTAINTY EXISTS IN WHERE
THIS BOUNDARY WILL SET UP...WHICH WILL DETERMINE HOW MUCH RAINFALL
WE WILL GET. ON TUESDAY...GEFS ENSEMBLE SPAGHETTI PLOTS GET MESSY
AND SIGNIFICANT DIFFERENCES START TO SHOW UP BETWEEN THE GFS AND
ECMWF...DECREASING CONFIDENCE ON HOW THE REST OF THE WEEK WILL SHAPE
UP.  AS OF NOW...THE MOST COMMON SOLUTION IS THAT HIGH PRESSURE
RIDGING WILL START TO BUILD BACK OVER THE WESTERN U.S. WHICH
SUGGESTS DRIER WEATHER STARTING TUESDAY...THOUGH UNCERTAINTY IS VERY
HIGH. -MCCOY

&&

.AVIATION...MAINLY VFR CONDITIONS ACROSS THE FORECAST AREA THIS
AFTERNOON...WITH A COUPLE NOTABLE EXCEPTIONS. IFR/LIFR CIGS
DEVELOPED THIS MORNING IN THE WILLAMETTE VALLEY KSLE SOUTHWARD...
AND HAVE LINGERED ALL DAY DUE TO LIGHT N-NE FLOW JAMMING THE LOW
CLOUDS AGAINST THE SOUTH END OF THE WILLAMETTE VALLEY. KSLE
APPEARS TO BE ON THE NORTHERN FRINGE OF THESE LOW CLOUDS...AND
WILL LIKELY REMAIN SO THROUGH THIS EVENING. CIGS WILL PROBABLY
DROP BACK DOWN TO NEAR THE DECK IN THESE AREAS TONIGHT AS -RA
DEVELOPS WITH OUR NEXT FRONTAL SYSTEM AND MOISTENS UP THE LOW
LEVEL AIR MASS.

ALSO EASTERLY UPSLOPE FLOW CAUSING MOUNTAIN OBSCURATIONS ALONG
THE EAST SLOPES AND CREST OF THE CASCADES...AND WILL LIKELY
CONTINUE TO DO SO OVERNIGHT TONIGHT.

WILL SEE AREAS -RA SPREAD NORTHWARD ACROSS MUCH OF THE FORECAST
AREA LATER TONIGHT...BUT IT APPEARS CIGS WILL GENERALLY REMAIN VFR
UNLESS OTHERWISE STATED ABOVE.WEAGLE

KPDX AND APPROACHES...VFR CIGS LIKELY REMAIN AT OR ABOVE 5 K FT
THROUGH THIS EVENING. SOME -RA IS POSSIBLE LATER TONIGHT AS
MOISTURE ASSOCIATED WITH AN OCCLUDED FRONT SPREADS NORTHWARD.
HOWEVER IT APPEARS CIGS SHOULD REMAIN VFR. LIGHT TO MODERATE
EASTERLY SFC WINDS THROUGH THIS EVENING.  WEAGLE

&&

.MARINE...VISIBLE SATELLITE IMAGERY SHOWS A WELL-DEFINED LOW
PRESSURE SYSTEM ABOUT 150 NM WEST OF CRESCENT CITY CA. THIS SYSTEM
APPEARS TO HAVE REACHED ITS MAXIMUM STRENGTH WITH A CENTRAL
PRESSURE AROUND 995 MB. FORECAST MODELS APPEAR TO HAVE GENERALLY
CAUGHT UP WITH THE STRENGTH OF THIS SYSTEM AFTER LAGGING BEHIND
EARLIER TODAY. THE LOW WILL DRIFT E-NE TONIGHT...PUSHING INTO WRN
OREGON BY WED. IT APPEARS E-NE WINDS CURLING AROUND THIS LOW WILL
BE ENOUGH TO PUSH GUSTS TO 25 KT IN OUR FAR SW WATERS...SO ISSUED
A SCA FOR WINDS IN THIS AREA THIS EVENING. AS THE LOW WEAKENS...
WINDS ASSOCIATED WITH THIS SYSTEM SHOULD WEAKEN AS WELL.

THE NEXT RELATIVELY STRONG FRONTAL SYSTEM IS BEGINNING TO TAKE
SHAPE BETWEEN 160W-170W...AND MAY PRODUCE GALES FOR OUR WATERS AS
IT MOVES ONSHORE LATER THU/EARLY FRI. THERE IS A GOOD POTENTIAL
FOR COASTAL JET FORMATION WHICH WOULD ENHANCE WINDS JUST AHEAD OF
THE FRONT WITH GUSTS TO 45 KT POSSIBLE NEAR THE COAST THU NIGHT.
AFTER COORDINATION WITH WFO SEATTLE...DECIDED CONFIDENCE WAS HIGH
ENOUGH TO WARRANT A GALE WATCH FOR THIS SYSTEM. 12Z ECMWF/GFS SHOW
THIS SYSTEM TAKING A NEAR-IDEAL TRACK AND SPEED FOR DYNAMIC
FETCH...AND THIS SHOWS IN THE WAVE MODELS. ENP GUIDANCE SUGGESTS
A SOLID 17-21 FT SWELL WITH A DOMINANT PERIOD OF 16-20 SECONDS
FOLLOWS THE FRONT...PROBABLY ENOUGH TO WARRANT A HIGH SURF
ADVISORY FRIDAY.  WEAGLE

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...GALE WATCH FROM THURSDAY MORNING THROUGH THURSDAY EVENING FOR
     COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR WINDS FROM 6 PM THIS EVENING TO
     MIDNIGHT PST TONIGHT FOR WATERS FROM CASCADE HEAD TO
     FLORENCE OR FROM 10 TO 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 11 PM
     THIS EVENING TO 3 AM PST WEDNESDAY.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 9 AM TO
     5 PM PST WEDNESDAY.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.



000
FXUS66 KPQR 162231
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
231 PM PST TUE DEC 16 2014

.SYNOPSIS...THERE WILL BE A BREAK IN RAIN THIS AFTERNOON BEFORE RAIN
ASSOCIATED WITH A LOW WEST OF THE CENTRAL OREGON COAST...MOVES SOUTH
TO NORTH THIS EVENING THROUGH WEDNESDAY MORNING. SHOWERS WILL
PRIMARILY BE OVER THE HIGHER TERRAIN. AN UPPER TROUGH WILL MAINTAIN A
CHANCE FOR SHOWERS THROUGH WEDNESDAY EVENING. A MORE ORGANIZED FRONT
WILL BRING GUSTY WINDS AND LARGE SURF TO THE COAST...WITH  RAIN
SPREADING INLAND THURSDAY NIGHT AND FRIDAY. RISING SNOW LEVELS WILL
LIMIT SNOW TO THE HIGHEST PEAKS...BUT COLDER AIR BEHIND THE FRONT MAY
RESULT IN SOME SNOW SHOWERS FOR THE CASCADES PASSES FRIDAY EVENING
AND SATURDAY. A WARMER AND MOISTER WEATHER IS EXPECTED THIS WEEKEND.

&&

.SHORT TERM...TONIGHT THROUGH FRIDAY...SHOWERS HAVE PRETTY MUCH ENDED
OVER THE PORTLAND FORECAST AREA EARLY THIS AFTERNOON...EXCEPT FOR
VERY INFREQUENT ISOLATED SHOWER OVER THE SW WASHINGTON CASCADES.
SATELLITE IMAGERY SHOWS A SURFACE LOW AROUND 150 MILES WEST OF THE
SOUTHERN OREGON COAST...NEAR 42N 127W. THE HIGHER RESOLUTION
MODELS...HRRR AND RAP INITIALIZE BEST WITH THE LOW AND FORECAST RAIN
MOVING NORTH INTO LANE COUNTY SLIGHTLY EARLIER THAN THE OTHER MODELS.
HAVE TRENDED TOWARDS THIS EARLIER ARRIVAL...BUT ONLY HAVE FAIR
CONFIDENCE THAT THE TIMING WILL PAN OUT. ANY RAIN LATE THIS AFTERNOON
SHOULD BE FAIRLY LIGHT AND REMAIN WEST OF THE SOUTH AND CENTRAL
WILLAMETTE VALLEY.

THE LOW WILL MOVE CLOSER TO THE SOUTHERN OREGON COAST LATE THIS
AFTERNOON AND EVENING THEN MOVE ONTO THE CENTRAL OREGON COAST AS AN
UPPER TROUGH LATE TONIGHT...WITH SHOWERS MAINLY OVER THE HIGHER
TERRAIN THROUGH WEDNESDAY MORNING. SOME CLEARING EARLY WED MORNING
MAY RESULT IN SHALLOW FOG AND LOW CLOUDS IN SOME OF THE INTERIOR
VALLEYS...MAINLY SOUTH OF SALEM.

EASTERLY WINDS HAVE HELD ON TODAY WITH A TROUTDALE TO DALLES PRESSURE
GRADIENT HOLDING AROUND 5 MB. THIS GRADIENT SHOULD TIGHTEN A LITTLE
THIS EVENING AS THE LOW MOVES CLOSER TO THE COAST AND MAINTAIN GUSTS
AROUND 30 MPH THROUGH THE WESTERN COLUMBIA RIVER GORGE.

SHOWERS WILL CONTINUE WEDNESDAY...MAINLY FOR THE HIGHER TERRAIN AS
THE PARENT UPPER LEVEL TROUGH MOVES OVER THE PACIFIC NW. SHOWERS
SHOULD END OVERNIGHT AS AN UPPER RIDGE BUILDS OVER THE AREA AND
EXPECT THAT CLEARING SKIES AND LIGHT WINDS WILL LEAD TO SHALLOW FOG
FOR THE INTERIOR VALLEYS EARLY THURSDAY MORNING. MOST OF THURSDAY
WILL BE DRY WITH AN INCREASE OF MID AN HIGH LEVEL CLOUDS IN THE
AFTERNOON.

MODELS ARE IN GOOD AGREEMENT THAT A WELL ORGANIZED FRONT WILL BRING
GUSTY WINDS TO THE COAST THURSDAY EVENING WITH RAIN SPREADING INLAND
THURSDAY NIGHT AND FRIDAY. PRECIPITABLE WATER IS EXPECTED TO BE NEAR
AN INCH AND AN APPROACHING JET STREAK SHOULD PROVIDE GOOD LIFT AND
EXPECT THE HIGHEST RAINFALL TOTALS OF 0.75 TO 1 INCH ACROSS THE
COAST AND COAST RANGE THURSDAY NIGHT THROUGH FRIDAY MORNING. OTHER
AREAS SHOULD SEE BETWEEN 0.4 AND 0.60 INCH OF RAIN. SNOW LEVELS
SHOULD REMAIN ABOVE 5000 FEET DURING THE PEAK RAIN PERIOD...BUT LOWER
TO NEAR OR BELOW THE CASCADE PASSES BEHIND THE FRONT FRIDAY
AFTERNOON.

.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY...A BROAD RIDGE OF HIGH
PRESSURE OVER THE WESTERN U.S. FLATTENS AS A STRONG LOW PRESSURE
SYSTEM OVER THE GULF OF ALASKA MOVES INLAND TO OUR NORTH. AS THIS
TROUGH MOVES ON SHORE SATURDAY...THE ASSOCIATED COLD FRONT MOVES
ONSHORE AND STALLS EAST-TO-WEST ACROSS NORTHWEST OREGON AND
SOUTHWEST WASHINGTON. THIS PUTS OUR AREA IN THE PATH OF RAIN
STARTING SATURDAY THROUGH MONDAY. SOME UNCERTAINTY EXISTS IN WHERE
THIS BOUNDARY WILL SET UP...WHICH WILL DETERMINE HOW MUCH RAINFALL
WE WILL GET. ON TUESDAY...GEFS ENSEMBLE SPAGHETTI PLOTS GET MESSY
AND SIGNIFICANT DIFFERENCES START TO SHOW UP BETWEEN THE GFS AND
ECMWF...DECREASING CONFIDENCE ON HOW THE REST OF THE WEEK WILL SHAPE
UP.  AS OF NOW...THE MOST COMMON SOLUTION IS THAT HIGH PRESSURE
RIDGING WILL START TO BUILD BACK OVER THE WESTERN U.S. WHICH
SUGGESTS DRIER WEATHER STARTING TUESDAY...THOUGH UNCERTAINTY IS VERY
HIGH. -MCCOY

&&

.AVIATION...MAINLY VFR CONDITIONS ACROSS THE FORECAST AREA THIS
AFTERNOON...WITH A COUPLE NOTABLE EXCEPTIONS. IFR/LIFR CIGS
DEVELOPED THIS MORNING IN THE WILLAMETTE VALLEY KSLE SOUTHWARD...
AND HAVE LINGERED ALL DAY DUE TO LIGHT N-NE FLOW JAMMING THE LOW
CLOUDS AGAINST THE SOUTH END OF THE WILLAMETTE VALLEY. KSLE
APPEARS TO BE ON THE NORTHERN FRINGE OF THESE LOW CLOUDS...AND
WILL LIKELY REMAIN SO THROUGH THIS EVENING. CIGS WILL PROBABLY
DROP BACK DOWN TO NEAR THE DECK IN THESE AREAS TONIGHT AS -RA
DEVELOPS WITH OUR NEXT FRONTAL SYSTEM AND MOISTENS UP THE LOW
LEVEL AIR MASS.

ALSO EASTERLY UPSLOPE FLOW CAUSING MOUNTAIN OBSCURATIONS ALONG
THE EAST SLOPES AND CREST OF THE CASCADES...AND WILL LIKELY
CONTINUE TO DO SO OVERNIGHT TONIGHT.

WILL SEE AREAS -RA SPREAD NORTHWARD ACROSS MUCH OF THE FORECAST
AREA LATER TONIGHT...BUT IT APPEARS CIGS WILL GENERALLY REMAIN VFR
UNLESS OTHERWISE STATED ABOVE.WEAGLE

KPDX AND APPROACHES...VFR CIGS LIKELY REMAIN AT OR ABOVE 5 K FT
THROUGH THIS EVENING. SOME -RA IS POSSIBLE LATER TONIGHT AS
MOISTURE ASSOCIATED WITH AN OCCLUDED FRONT SPREADS NORTHWARD.
HOWEVER IT APPEARS CIGS SHOULD REMAIN VFR. LIGHT TO MODERATE
EASTERLY SFC WINDS THROUGH THIS EVENING.  WEAGLE

&&

.MARINE...VISIBLE SATELLITE IMAGERY SHOWS A WELL-DEFINED LOW
PRESSURE SYSTEM ABOUT 150 NM WEST OF CRESCENT CITY CA. THIS SYSTEM
APPEARS TO HAVE REACHED ITS MAXIMUM STRENGTH WITH A CENTRAL
PRESSURE AROUND 995 MB. FORECAST MODELS APPEAR TO HAVE GENERALLY
CAUGHT UP WITH THE STRENGTH OF THIS SYSTEM AFTER LAGGING BEHIND
EARLIER TODAY. THE LOW WILL DRIFT E-NE TONIGHT...PUSHING INTO WRN
OREGON BY WED. IT APPEARS E-NE WINDS CURLING AROUND THIS LOW WILL
BE ENOUGH TO PUSH GUSTS TO 25 KT IN OUR FAR SW WATERS...SO ISSUED
A SCA FOR WINDS IN THIS AREA THIS EVENING. AS THE LOW WEAKENS...
WINDS ASSOCIATED WITH THIS SYSTEM SHOULD WEAKEN AS WELL.

THE NEXT RELATIVELY STRONG FRONTAL SYSTEM IS BEGINNING TO TAKE
SHAPE BETWEEN 160W-170W...AND MAY PRODUCE GALES FOR OUR WATERS AS
IT MOVES ONSHORE LATER THU/EARLY FRI. THERE IS A GOOD POTENTIAL
FOR COASTAL JET FORMATION WHICH WOULD ENHANCE WINDS JUST AHEAD OF
THE FRONT WITH GUSTS TO 45 KT POSSIBLE NEAR THE COAST THU NIGHT.
AFTER COORDINATION WITH WFO SEATTLE...DECIDED CONFIDENCE WAS HIGH
ENOUGH TO WARRANT A GALE WATCH FOR THIS SYSTEM. 12Z ECMWF/GFS SHOW
THIS SYSTEM TAKING A NEAR-IDEAL TRACK AND SPEED FOR DYNAMIC
FETCH...AND THIS SHOWS IN THE WAVE MODELS. ENP GUIDANCE SUGGESTS
A SOLID 17-21 FT SWELL WITH A DOMINANT PERIOD OF 16-20 SECONDS
FOLLOWS THE FRONT...PROBABLY ENOUGH TO WARRANT A HIGH SURF
ADVISORY FRIDAY.  WEAGLE

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...GALE WATCH FROM THURSDAY MORNING THROUGH THURSDAY EVENING FOR
     COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR WINDS FROM 6 PM THIS EVENING TO
     MIDNIGHT PST TONIGHT FOR WATERS FROM CASCADE HEAD TO
     FLORENCE OR FROM 10 TO 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 11 PM
     THIS EVENING TO 3 AM PST WEDNESDAY.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 9 AM TO
     5 PM PST WEDNESDAY.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.



000
FXUS66 KPQR 162231
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
231 PM PST TUE DEC 16 2014

.SYNOPSIS...THERE WILL BE A BREAK IN RAIN THIS AFTERNOON BEFORE RAIN
ASSOCIATED WITH A LOW WEST OF THE CENTRAL OREGON COAST...MOVES SOUTH
TO NORTH THIS EVENING THROUGH WEDNESDAY MORNING. SHOWERS WILL
PRIMARILY BE OVER THE HIGHER TERRAIN. AN UPPER TROUGH WILL MAINTAIN A
CHANCE FOR SHOWERS THROUGH WEDNESDAY EVENING. A MORE ORGANIZED FRONT
WILL BRING GUSTY WINDS AND LARGE SURF TO THE COAST...WITH  RAIN
SPREADING INLAND THURSDAY NIGHT AND FRIDAY. RISING SNOW LEVELS WILL
LIMIT SNOW TO THE HIGHEST PEAKS...BUT COLDER AIR BEHIND THE FRONT MAY
RESULT IN SOME SNOW SHOWERS FOR THE CASCADES PASSES FRIDAY EVENING
AND SATURDAY. A WARMER AND MOISTER WEATHER IS EXPECTED THIS WEEKEND.

&&

.SHORT TERM...TONIGHT THROUGH FRIDAY...SHOWERS HAVE PRETTY MUCH ENDED
OVER THE PORTLAND FORECAST AREA EARLY THIS AFTERNOON...EXCEPT FOR
VERY INFREQUENT ISOLATED SHOWER OVER THE SW WASHINGTON CASCADES.
SATELLITE IMAGERY SHOWS A SURFACE LOW AROUND 150 MILES WEST OF THE
SOUTHERN OREGON COAST...NEAR 42N 127W. THE HIGHER RESOLUTION
MODELS...HRRR AND RAP INITIALIZE BEST WITH THE LOW AND FORECAST RAIN
MOVING NORTH INTO LANE COUNTY SLIGHTLY EARLIER THAN THE OTHER MODELS.
HAVE TRENDED TOWARDS THIS EARLIER ARRIVAL...BUT ONLY HAVE FAIR
CONFIDENCE THAT THE TIMING WILL PAN OUT. ANY RAIN LATE THIS AFTERNOON
SHOULD BE FAIRLY LIGHT AND REMAIN WEST OF THE SOUTH AND CENTRAL
WILLAMETTE VALLEY.

THE LOW WILL MOVE CLOSER TO THE SOUTHERN OREGON COAST LATE THIS
AFTERNOON AND EVENING THEN MOVE ONTO THE CENTRAL OREGON COAST AS AN
UPPER TROUGH LATE TONIGHT...WITH SHOWERS MAINLY OVER THE HIGHER
TERRAIN THROUGH WEDNESDAY MORNING. SOME CLEARING EARLY WED MORNING
MAY RESULT IN SHALLOW FOG AND LOW CLOUDS IN SOME OF THE INTERIOR
VALLEYS...MAINLY SOUTH OF SALEM.

EASTERLY WINDS HAVE HELD ON TODAY WITH A TROUTDALE TO DALLES PRESSURE
GRADIENT HOLDING AROUND 5 MB. THIS GRADIENT SHOULD TIGHTEN A LITTLE
THIS EVENING AS THE LOW MOVES CLOSER TO THE COAST AND MAINTAIN GUSTS
AROUND 30 MPH THROUGH THE WESTERN COLUMBIA RIVER GORGE.

SHOWERS WILL CONTINUE WEDNESDAY...MAINLY FOR THE HIGHER TERRAIN AS
THE PARENT UPPER LEVEL TROUGH MOVES OVER THE PACIFIC NW. SHOWERS
SHOULD END OVERNIGHT AS AN UPPER RIDGE BUILDS OVER THE AREA AND
EXPECT THAT CLEARING SKIES AND LIGHT WINDS WILL LEAD TO SHALLOW FOG
FOR THE INTERIOR VALLEYS EARLY THURSDAY MORNING. MOST OF THURSDAY
WILL BE DRY WITH AN INCREASE OF MID AN HIGH LEVEL CLOUDS IN THE
AFTERNOON.

MODELS ARE IN GOOD AGREEMENT THAT A WELL ORGANIZED FRONT WILL BRING
GUSTY WINDS TO THE COAST THURSDAY EVENING WITH RAIN SPREADING INLAND
THURSDAY NIGHT AND FRIDAY. PRECIPITABLE WATER IS EXPECTED TO BE NEAR
AN INCH AND AN APPROACHING JET STREAK SHOULD PROVIDE GOOD LIFT AND
EXPECT THE HIGHEST RAINFALL TOTALS OF 0.75 TO 1 INCH ACROSS THE
COAST AND COAST RANGE THURSDAY NIGHT THROUGH FRIDAY MORNING. OTHER
AREAS SHOULD SEE BETWEEN 0.4 AND 0.60 INCH OF RAIN. SNOW LEVELS
SHOULD REMAIN ABOVE 5000 FEET DURING THE PEAK RAIN PERIOD...BUT LOWER
TO NEAR OR BELOW THE CASCADE PASSES BEHIND THE FRONT FRIDAY
AFTERNOON.

.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY...A BROAD RIDGE OF HIGH
PRESSURE OVER THE WESTERN U.S. FLATTENS AS A STRONG LOW PRESSURE
SYSTEM OVER THE GULF OF ALASKA MOVES INLAND TO OUR NORTH. AS THIS
TROUGH MOVES ON SHORE SATURDAY...THE ASSOCIATED COLD FRONT MOVES
ONSHORE AND STALLS EAST-TO-WEST ACROSS NORTHWEST OREGON AND
SOUTHWEST WASHINGTON. THIS PUTS OUR AREA IN THE PATH OF RAIN
STARTING SATURDAY THROUGH MONDAY. SOME UNCERTAINTY EXISTS IN WHERE
THIS BOUNDARY WILL SET UP...WHICH WILL DETERMINE HOW MUCH RAINFALL
WE WILL GET. ON TUESDAY...GEFS ENSEMBLE SPAGHETTI PLOTS GET MESSY
AND SIGNIFICANT DIFFERENCES START TO SHOW UP BETWEEN THE GFS AND
ECMWF...DECREASING CONFIDENCE ON HOW THE REST OF THE WEEK WILL SHAPE
UP.  AS OF NOW...THE MOST COMMON SOLUTION IS THAT HIGH PRESSURE
RIDGING WILL START TO BUILD BACK OVER THE WESTERN U.S. WHICH
SUGGESTS DRIER WEATHER STARTING TUESDAY...THOUGH UNCERTAINTY IS VERY
HIGH. -MCCOY

&&

.AVIATION...MAINLY VFR CONDITIONS ACROSS THE FORECAST AREA THIS
AFTERNOON...WITH A COUPLE NOTABLE EXCEPTIONS. IFR/LIFR CIGS
DEVELOPED THIS MORNING IN THE WILLAMETTE VALLEY KSLE SOUTHWARD...
AND HAVE LINGERED ALL DAY DUE TO LIGHT N-NE FLOW JAMMING THE LOW
CLOUDS AGAINST THE SOUTH END OF THE WILLAMETTE VALLEY. KSLE
APPEARS TO BE ON THE NORTHERN FRINGE OF THESE LOW CLOUDS...AND
WILL LIKELY REMAIN SO THROUGH THIS EVENING. CIGS WILL PROBABLY
DROP BACK DOWN TO NEAR THE DECK IN THESE AREAS TONIGHT AS -RA
DEVELOPS WITH OUR NEXT FRONTAL SYSTEM AND MOISTENS UP THE LOW
LEVEL AIR MASS.

ALSO EASTERLY UPSLOPE FLOW CAUSING MOUNTAIN OBSCURATIONS ALONG
THE EAST SLOPES AND CREST OF THE CASCADES...AND WILL LIKELY
CONTINUE TO DO SO OVERNIGHT TONIGHT.

WILL SEE AREAS -RA SPREAD NORTHWARD ACROSS MUCH OF THE FORECAST
AREA LATER TONIGHT...BUT IT APPEARS CIGS WILL GENERALLY REMAIN VFR
UNLESS OTHERWISE STATED ABOVE.WEAGLE

KPDX AND APPROACHES...VFR CIGS LIKELY REMAIN AT OR ABOVE 5 K FT
THROUGH THIS EVENING. SOME -RA IS POSSIBLE LATER TONIGHT AS
MOISTURE ASSOCIATED WITH AN OCCLUDED FRONT SPREADS NORTHWARD.
HOWEVER IT APPEARS CIGS SHOULD REMAIN VFR. LIGHT TO MODERATE
EASTERLY SFC WINDS THROUGH THIS EVENING.  WEAGLE

&&

.MARINE...VISIBLE SATELLITE IMAGERY SHOWS A WELL-DEFINED LOW
PRESSURE SYSTEM ABOUT 150 NM WEST OF CRESCENT CITY CA. THIS SYSTEM
APPEARS TO HAVE REACHED ITS MAXIMUM STRENGTH WITH A CENTRAL
PRESSURE AROUND 995 MB. FORECAST MODELS APPEAR TO HAVE GENERALLY
CAUGHT UP WITH THE STRENGTH OF THIS SYSTEM AFTER LAGGING BEHIND
EARLIER TODAY. THE LOW WILL DRIFT E-NE TONIGHT...PUSHING INTO WRN
OREGON BY WED. IT APPEARS E-NE WINDS CURLING AROUND THIS LOW WILL
BE ENOUGH TO PUSH GUSTS TO 25 KT IN OUR FAR SW WATERS...SO ISSUED
A SCA FOR WINDS IN THIS AREA THIS EVENING. AS THE LOW WEAKENS...
WINDS ASSOCIATED WITH THIS SYSTEM SHOULD WEAKEN AS WELL.

THE NEXT RELATIVELY STRONG FRONTAL SYSTEM IS BEGINNING TO TAKE
SHAPE BETWEEN 160W-170W...AND MAY PRODUCE GALES FOR OUR WATERS AS
IT MOVES ONSHORE LATER THU/EARLY FRI. THERE IS A GOOD POTENTIAL
FOR COASTAL JET FORMATION WHICH WOULD ENHANCE WINDS JUST AHEAD OF
THE FRONT WITH GUSTS TO 45 KT POSSIBLE NEAR THE COAST THU NIGHT.
AFTER COORDINATION WITH WFO SEATTLE...DECIDED CONFIDENCE WAS HIGH
ENOUGH TO WARRANT A GALE WATCH FOR THIS SYSTEM. 12Z ECMWF/GFS SHOW
THIS SYSTEM TAKING A NEAR-IDEAL TRACK AND SPEED FOR DYNAMIC
FETCH...AND THIS SHOWS IN THE WAVE MODELS. ENP GUIDANCE SUGGESTS
A SOLID 17-21 FT SWELL WITH A DOMINANT PERIOD OF 16-20 SECONDS
FOLLOWS THE FRONT...PROBABLY ENOUGH TO WARRANT A HIGH SURF
ADVISORY FRIDAY.  WEAGLE

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...GALE WATCH FROM THURSDAY MORNING THROUGH THURSDAY EVENING FOR
     COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR WINDS FROM 6 PM THIS EVENING TO
     MIDNIGHT PST TONIGHT FOR WATERS FROM CASCADE HEAD TO
     FLORENCE OR FROM 10 TO 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 11 PM
     THIS EVENING TO 3 AM PST WEDNESDAY.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 9 AM TO
     5 PM PST WEDNESDAY.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.



000
FXUS66 KPQR 162231
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
231 PM PST TUE DEC 16 2014

.SYNOPSIS...THERE WILL BE A BREAK IN RAIN THIS AFTERNOON BEFORE RAIN
ASSOCIATED WITH A LOW WEST OF THE CENTRAL OREGON COAST...MOVES SOUTH
TO NORTH THIS EVENING THROUGH WEDNESDAY MORNING. SHOWERS WILL
PRIMARILY BE OVER THE HIGHER TERRAIN. AN UPPER TROUGH WILL MAINTAIN A
CHANCE FOR SHOWERS THROUGH WEDNESDAY EVENING. A MORE ORGANIZED FRONT
WILL BRING GUSTY WINDS AND LARGE SURF TO THE COAST...WITH  RAIN
SPREADING INLAND THURSDAY NIGHT AND FRIDAY. RISING SNOW LEVELS WILL
LIMIT SNOW TO THE HIGHEST PEAKS...BUT COLDER AIR BEHIND THE FRONT MAY
RESULT IN SOME SNOW SHOWERS FOR THE CASCADES PASSES FRIDAY EVENING
AND SATURDAY. A WARMER AND MOISTER WEATHER IS EXPECTED THIS WEEKEND.

&&

.SHORT TERM...TONIGHT THROUGH FRIDAY...SHOWERS HAVE PRETTY MUCH ENDED
OVER THE PORTLAND FORECAST AREA EARLY THIS AFTERNOON...EXCEPT FOR
VERY INFREQUENT ISOLATED SHOWER OVER THE SW WASHINGTON CASCADES.
SATELLITE IMAGERY SHOWS A SURFACE LOW AROUND 150 MILES WEST OF THE
SOUTHERN OREGON COAST...NEAR 42N 127W. THE HIGHER RESOLUTION
MODELS...HRRR AND RAP INITIALIZE BEST WITH THE LOW AND FORECAST RAIN
MOVING NORTH INTO LANE COUNTY SLIGHTLY EARLIER THAN THE OTHER MODELS.
HAVE TRENDED TOWARDS THIS EARLIER ARRIVAL...BUT ONLY HAVE FAIR
CONFIDENCE THAT THE TIMING WILL PAN OUT. ANY RAIN LATE THIS AFTERNOON
SHOULD BE FAIRLY LIGHT AND REMAIN WEST OF THE SOUTH AND CENTRAL
WILLAMETTE VALLEY.

THE LOW WILL MOVE CLOSER TO THE SOUTHERN OREGON COAST LATE THIS
AFTERNOON AND EVENING THEN MOVE ONTO THE CENTRAL OREGON COAST AS AN
UPPER TROUGH LATE TONIGHT...WITH SHOWERS MAINLY OVER THE HIGHER
TERRAIN THROUGH WEDNESDAY MORNING. SOME CLEARING EARLY WED MORNING
MAY RESULT IN SHALLOW FOG AND LOW CLOUDS IN SOME OF THE INTERIOR
VALLEYS...MAINLY SOUTH OF SALEM.

EASTERLY WINDS HAVE HELD ON TODAY WITH A TROUTDALE TO DALLES PRESSURE
GRADIENT HOLDING AROUND 5 MB. THIS GRADIENT SHOULD TIGHTEN A LITTLE
THIS EVENING AS THE LOW MOVES CLOSER TO THE COAST AND MAINTAIN GUSTS
AROUND 30 MPH THROUGH THE WESTERN COLUMBIA RIVER GORGE.

SHOWERS WILL CONTINUE WEDNESDAY...MAINLY FOR THE HIGHER TERRAIN AS
THE PARENT UPPER LEVEL TROUGH MOVES OVER THE PACIFIC NW. SHOWERS
SHOULD END OVERNIGHT AS AN UPPER RIDGE BUILDS OVER THE AREA AND
EXPECT THAT CLEARING SKIES AND LIGHT WINDS WILL LEAD TO SHALLOW FOG
FOR THE INTERIOR VALLEYS EARLY THURSDAY MORNING. MOST OF THURSDAY
WILL BE DRY WITH AN INCREASE OF MID AN HIGH LEVEL CLOUDS IN THE
AFTERNOON.

MODELS ARE IN GOOD AGREEMENT THAT A WELL ORGANIZED FRONT WILL BRING
GUSTY WINDS TO THE COAST THURSDAY EVENING WITH RAIN SPREADING INLAND
THURSDAY NIGHT AND FRIDAY. PRECIPITABLE WATER IS EXPECTED TO BE NEAR
AN INCH AND AN APPROACHING JET STREAK SHOULD PROVIDE GOOD LIFT AND
EXPECT THE HIGHEST RAINFALL TOTALS OF 0.75 TO 1 INCH ACROSS THE
COAST AND COAST RANGE THURSDAY NIGHT THROUGH FRIDAY MORNING. OTHER
AREAS SHOULD SEE BETWEEN 0.4 AND 0.60 INCH OF RAIN. SNOW LEVELS
SHOULD REMAIN ABOVE 5000 FEET DURING THE PEAK RAIN PERIOD...BUT LOWER
TO NEAR OR BELOW THE CASCADE PASSES BEHIND THE FRONT FRIDAY
AFTERNOON.

.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY...A BROAD RIDGE OF HIGH
PRESSURE OVER THE WESTERN U.S. FLATTENS AS A STRONG LOW PRESSURE
SYSTEM OVER THE GULF OF ALASKA MOVES INLAND TO OUR NORTH. AS THIS
TROUGH MOVES ON SHORE SATURDAY...THE ASSOCIATED COLD FRONT MOVES
ONSHORE AND STALLS EAST-TO-WEST ACROSS NORTHWEST OREGON AND
SOUTHWEST WASHINGTON. THIS PUTS OUR AREA IN THE PATH OF RAIN
STARTING SATURDAY THROUGH MONDAY. SOME UNCERTAINTY EXISTS IN WHERE
THIS BOUNDARY WILL SET UP...WHICH WILL DETERMINE HOW MUCH RAINFALL
WE WILL GET. ON TUESDAY...GEFS ENSEMBLE SPAGHETTI PLOTS GET MESSY
AND SIGNIFICANT DIFFERENCES START TO SHOW UP BETWEEN THE GFS AND
ECMWF...DECREASING CONFIDENCE ON HOW THE REST OF THE WEEK WILL SHAPE
UP.  AS OF NOW...THE MOST COMMON SOLUTION IS THAT HIGH PRESSURE
RIDGING WILL START TO BUILD BACK OVER THE WESTERN U.S. WHICH
SUGGESTS DRIER WEATHER STARTING TUESDAY...THOUGH UNCERTAINTY IS VERY
HIGH. -MCCOY

&&

.AVIATION...MAINLY VFR CONDITIONS ACROSS THE FORECAST AREA THIS
AFTERNOON...WITH A COUPLE NOTABLE EXCEPTIONS. IFR/LIFR CIGS
DEVELOPED THIS MORNING IN THE WILLAMETTE VALLEY KSLE SOUTHWARD...
AND HAVE LINGERED ALL DAY DUE TO LIGHT N-NE FLOW JAMMING THE LOW
CLOUDS AGAINST THE SOUTH END OF THE WILLAMETTE VALLEY. KSLE
APPEARS TO BE ON THE NORTHERN FRINGE OF THESE LOW CLOUDS...AND
WILL LIKELY REMAIN SO THROUGH THIS EVENING. CIGS WILL PROBABLY
DROP BACK DOWN TO NEAR THE DECK IN THESE AREAS TONIGHT AS -RA
DEVELOPS WITH OUR NEXT FRONTAL SYSTEM AND MOISTENS UP THE LOW
LEVEL AIR MASS.

ALSO EASTERLY UPSLOPE FLOW CAUSING MOUNTAIN OBSCURATIONS ALONG
THE EAST SLOPES AND CREST OF THE CASCADES...AND WILL LIKELY
CONTINUE TO DO SO OVERNIGHT TONIGHT.

WILL SEE AREAS -RA SPREAD NORTHWARD ACROSS MUCH OF THE FORECAST
AREA LATER TONIGHT...BUT IT APPEARS CIGS WILL GENERALLY REMAIN VFR
UNLESS OTHERWISE STATED ABOVE.WEAGLE

KPDX AND APPROACHES...VFR CIGS LIKELY REMAIN AT OR ABOVE 5 K FT
THROUGH THIS EVENING. SOME -RA IS POSSIBLE LATER TONIGHT AS
MOISTURE ASSOCIATED WITH AN OCCLUDED FRONT SPREADS NORTHWARD.
HOWEVER IT APPEARS CIGS SHOULD REMAIN VFR. LIGHT TO MODERATE
EASTERLY SFC WINDS THROUGH THIS EVENING.  WEAGLE

&&

.MARINE...VISIBLE SATELLITE IMAGERY SHOWS A WELL-DEFINED LOW
PRESSURE SYSTEM ABOUT 150 NM WEST OF CRESCENT CITY CA. THIS SYSTEM
APPEARS TO HAVE REACHED ITS MAXIMUM STRENGTH WITH A CENTRAL
PRESSURE AROUND 995 MB. FORECAST MODELS APPEAR TO HAVE GENERALLY
CAUGHT UP WITH THE STRENGTH OF THIS SYSTEM AFTER LAGGING BEHIND
EARLIER TODAY. THE LOW WILL DRIFT E-NE TONIGHT...PUSHING INTO WRN
OREGON BY WED. IT APPEARS E-NE WINDS CURLING AROUND THIS LOW WILL
BE ENOUGH TO PUSH GUSTS TO 25 KT IN OUR FAR SW WATERS...SO ISSUED
A SCA FOR WINDS IN THIS AREA THIS EVENING. AS THE LOW WEAKENS...
WINDS ASSOCIATED WITH THIS SYSTEM SHOULD WEAKEN AS WELL.

THE NEXT RELATIVELY STRONG FRONTAL SYSTEM IS BEGINNING TO TAKE
SHAPE BETWEEN 160W-170W...AND MAY PRODUCE GALES FOR OUR WATERS AS
IT MOVES ONSHORE LATER THU/EARLY FRI. THERE IS A GOOD POTENTIAL
FOR COASTAL JET FORMATION WHICH WOULD ENHANCE WINDS JUST AHEAD OF
THE FRONT WITH GUSTS TO 45 KT POSSIBLE NEAR THE COAST THU NIGHT.
AFTER COORDINATION WITH WFO SEATTLE...DECIDED CONFIDENCE WAS HIGH
ENOUGH TO WARRANT A GALE WATCH FOR THIS SYSTEM. 12Z ECMWF/GFS SHOW
THIS SYSTEM TAKING A NEAR-IDEAL TRACK AND SPEED FOR DYNAMIC
FETCH...AND THIS SHOWS IN THE WAVE MODELS. ENP GUIDANCE SUGGESTS
A SOLID 17-21 FT SWELL WITH A DOMINANT PERIOD OF 16-20 SECONDS
FOLLOWS THE FRONT...PROBABLY ENOUGH TO WARRANT A HIGH SURF
ADVISORY FRIDAY.  WEAGLE

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...GALE WATCH FROM THURSDAY MORNING THROUGH THURSDAY EVENING FOR
     COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR WINDS FROM 6 PM THIS EVENING TO
     MIDNIGHT PST TONIGHT FOR WATERS FROM CASCADE HEAD TO
     FLORENCE OR FROM 10 TO 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 11 PM
     THIS EVENING TO 3 AM PST WEDNESDAY.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 9 AM TO
     5 PM PST WEDNESDAY.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.



000
FXUS66 KOTX 161933
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1132 AM PST TUE DEC 16 2014

.SYNOPSIS...
A weak storm system will bring light accumulations of snow
today to the areas near the Cascades and light rain or snow to the
western Columbia Basin. A more active weather pattern will
develop late in the week with generally mountain snow and valley
rain or minimally accumulating snow.

&&

.DISCUSSION...
Another update to increase the localized pops associated with the
mesoscale circulation near the tri-cities on radar right now.
Expectation is this circulation will drift northeast through
Southeast Washington but influence will be localized. By 00Z this
afternoon it should be within close proximity to the West Plains
of Spokane, Eastern Lincoln, Northeast Adams, and Nortwest Whitman
Counties and by 3Z its up in the northern mountains but by then it
is expected to weaken considerably and quickly. Amounts of rain or
snow expected to fall out of this small circulation are on the
light side on the order of .05 liquid or less. /Pelatti

&&

.AVIATION...
18Z TAFS: Weak upper level disturbance working its way through the
aviation area this morning. A second weak disturbance that is
smaller is followiong quickly behind and will pass today as well.
So for the most part the precipitation is expect to be rather
light and produce and/or enhance ongoing MVFR ceilings and
visibilites today...but locations nearest very localized higher
intensity precipitation could dip to VFR at times. Overnight the
expecation is these two disturbances will have cleared the area
and fog/low clouds will continue to be an issue. /Pelatti



&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        36  29  38  32  37  31 /  10  50  10  40  30  10
Coeur d`Alene  37  30  40  33  38  31 /  10  30  10  50  50  10
Pullman        40  29  42  32  41  32 /  30  30  10  50  30  10
Lewiston       43  32  42  35  43  34 /   0  10  10  40  30  10
Colville       34  28  36  31  37  31 /  40  30  20  40  30  20
Sandpoint      35  28  36  30  36  31 /  10  20  10  60  60  20
Kellogg        37  30  38  31  36  30 /  10  20  10  70  60  20
Moses Lake     37  28  38  28  38  30 /  20  10  20  20  10  30
Wenatchee      36  31  37  30  36  31 /  60  10  30  30  10  30
Omak           34  26  34  27  33  28 /  60  30  40  40  10  30

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$




000
FXUS66 KOTX 161933
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1132 AM PST TUE DEC 16 2014

.SYNOPSIS...
A weak storm system will bring light accumulations of snow
today to the areas near the Cascades and light rain or snow to the
western Columbia Basin. A more active weather pattern will
develop late in the week with generally mountain snow and valley
rain or minimally accumulating snow.

&&

.DISCUSSION...
Another update to increase the localized pops associated with the
mesoscale circulation near the tri-cities on radar right now.
Expectation is this circulation will drift northeast through
Southeast Washington but influence will be localized. By 00Z this
afternoon it should be within close proximity to the West Plains
of Spokane, Eastern Lincoln, Northeast Adams, and Nortwest Whitman
Counties and by 3Z its up in the northern mountains but by then it
is expected to weaken considerably and quickly. Amounts of rain or
snow expected to fall out of this small circulation are on the
light side on the order of .05 liquid or less. /Pelatti

&&

.AVIATION...
18Z TAFS: Weak upper level disturbance working its way through the
aviation area this morning. A second weak disturbance that is
smaller is followiong quickly behind and will pass today as well.
So for the most part the precipitation is expect to be rather
light and produce and/or enhance ongoing MVFR ceilings and
visibilites today...but locations nearest very localized higher
intensity precipitation could dip to VFR at times. Overnight the
expecation is these two disturbances will have cleared the area
and fog/low clouds will continue to be an issue. /Pelatti



&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        36  29  38  32  37  31 /  10  50  10  40  30  10
Coeur d`Alene  37  30  40  33  38  31 /  10  30  10  50  50  10
Pullman        40  29  42  32  41  32 /  30  30  10  50  30  10
Lewiston       43  32  42  35  43  34 /   0  10  10  40  30  10
Colville       34  28  36  31  37  31 /  40  30  20  40  30  20
Sandpoint      35  28  36  30  36  31 /  10  20  10  60  60  20
Kellogg        37  30  38  31  36  30 /  10  20  10  70  60  20
Moses Lake     37  28  38  28  38  30 /  20  10  20  20  10  30
Wenatchee      36  31  37  30  36  31 /  60  10  30  30  10  30
Omak           34  26  34  27  33  28 /  60  30  40  40  10  30

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$




000
FXUS66 KOTX 161933
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1132 AM PST TUE DEC 16 2014

.SYNOPSIS...
A weak storm system will bring light accumulations of snow
today to the areas near the Cascades and light rain or snow to the
western Columbia Basin. A more active weather pattern will
develop late in the week with generally mountain snow and valley
rain or minimally accumulating snow.

&&

.DISCUSSION...
Another update to increase the localized pops associated with the
mesoscale circulation near the tri-cities on radar right now.
Expectation is this circulation will drift northeast through
Southeast Washington but influence will be localized. By 00Z this
afternoon it should be within close proximity to the West Plains
of Spokane, Eastern Lincoln, Northeast Adams, and Nortwest Whitman
Counties and by 3Z its up in the northern mountains but by then it
is expected to weaken considerably and quickly. Amounts of rain or
snow expected to fall out of this small circulation are on the
light side on the order of .05 liquid or less. /Pelatti

&&

.AVIATION...
18Z TAFS: Weak upper level disturbance working its way through the
aviation area this morning. A second weak disturbance that is
smaller is followiong quickly behind and will pass today as well.
So for the most part the precipitation is expect to be rather
light and produce and/or enhance ongoing MVFR ceilings and
visibilites today...but locations nearest very localized higher
intensity precipitation could dip to VFR at times. Overnight the
expecation is these two disturbances will have cleared the area
and fog/low clouds will continue to be an issue. /Pelatti



&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        36  29  38  32  37  31 /  10  50  10  40  30  10
Coeur d`Alene  37  30  40  33  38  31 /  10  30  10  50  50  10
Pullman        40  29  42  32  41  32 /  30  30  10  50  30  10
Lewiston       43  32  42  35  43  34 /   0  10  10  40  30  10
Colville       34  28  36  31  37  31 /  40  30  20  40  30  20
Sandpoint      35  28  36  30  36  31 /  10  20  10  60  60  20
Kellogg        37  30  38  31  36  30 /  10  20  10  70  60  20
Moses Lake     37  28  38  28  38  30 /  20  10  20  20  10  30
Wenatchee      36  31  37  30  36  31 /  60  10  30  30  10  30
Omak           34  26  34  27  33  28 /  60  30  40  40  10  30

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$




000
FXUS66 KOTX 161933
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1132 AM PST TUE DEC 16 2014

.SYNOPSIS...
A weak storm system will bring light accumulations of snow
today to the areas near the Cascades and light rain or snow to the
western Columbia Basin. A more active weather pattern will
develop late in the week with generally mountain snow and valley
rain or minimally accumulating snow.

&&

.DISCUSSION...
Another update to increase the localized pops associated with the
mesoscale circulation near the tri-cities on radar right now.
Expectation is this circulation will drift northeast through
Southeast Washington but influence will be localized. By 00Z this
afternoon it should be within close proximity to the West Plains
of Spokane, Eastern Lincoln, Northeast Adams, and Nortwest Whitman
Counties and by 3Z its up in the northern mountains but by then it
is expected to weaken considerably and quickly. Amounts of rain or
snow expected to fall out of this small circulation are on the
light side on the order of .05 liquid or less. /Pelatti

&&

.AVIATION...
18Z TAFS: Weak upper level disturbance working its way through the
aviation area this morning. A second weak disturbance that is
smaller is followiong quickly behind and will pass today as well.
So for the most part the precipitation is expect to be rather
light and produce and/or enhance ongoing MVFR ceilings and
visibilites today...but locations nearest very localized higher
intensity precipitation could dip to VFR at times. Overnight the
expecation is these two disturbances will have cleared the area
and fog/low clouds will continue to be an issue. /Pelatti



&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        36  29  38  32  37  31 /  10  50  10  40  30  10
Coeur d`Alene  37  30  40  33  38  31 /  10  30  10  50  50  10
Pullman        40  29  42  32  41  32 /  30  30  10  50  30  10
Lewiston       43  32  42  35  43  34 /   0  10  10  40  30  10
Colville       34  28  36  31  37  31 /  40  30  20  40  30  20
Sandpoint      35  28  36  30  36  31 /  10  20  10  60  60  20
Kellogg        37  30  38  31  36  30 /  10  20  10  70  60  20
Moses Lake     37  28  38  28  38  30 /  20  10  20  20  10  30
Wenatchee      36  31  37  30  36  31 /  60  10  30  30  10  30
Omak           34  26  34  27  33  28 /  60  30  40  40  10  30

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$




000
FXUS66 KOTX 161807
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1007 AM PST TUE DEC 16 2014

.SYNOPSIS...
A weak storm system will bring light accumulations of snow
today to the areas near the Cascades and light rain or snow to the
western Columbia Basin. A more active weather pattern will
develop late in the week with generally mountain snow and valley
rain or minimally accumulating snow.

&&

.DISCUSSION...
Second update of the morning to add slight chance pops for a
second weather disturbance to work its way up through the forecast
area today and early this evening. Current radar shows the small
counter clockwise rotating circulation producing rain near the
tri- cities area which is expected to de-intesify some through the
day but by later today into the early evening some re-intensification
of the circulation when it is in the vicinity of the Columba
Basin, Spokane, and Washington Palouse area. It quickly falls
apart in the evening per a number of HRRR model runs so the pops
and qpf assigned to it remain small at this point in time.
/Pelatti

&&

.AVIATION...
18Z TAFS: Weak upper level disturbance working its way through the
aviation area this morning. A second weak disturbance that is
smaller is followiong quickly behind and will pass today as well.
So for the most part the precipitation is expect to be rather
light and produce and/or enhance ongoing MVFR ceilings and
visibilites today...but locations nearest very localized higher
intensity precipitation could dip to VFR at times. Overnight the
expecation is these two disturbances will have cleared the area
and fog/low clouds will continue to be an issue. /Pelatti


&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        36  29  38  32  37  31 /  10  20  10  30  30  10
Coeur d`Alene  37  30  40  33  38  31 /  10  20  10  40  40  10
Pullman        40  29  42  32  41  32 /  10  20  10  30  30  10
Lewiston       43  32  42  35  43  34 /   0  10  10  30  30  10
Colville       34  28  36  31  37  31 /  40  30  20  30  30  20
Sandpoint      35  28  36  30  36  31 /  10  20  10  40  40  20
Kellogg        37  30  38  31  36  30 /  10  20  10  40  40  20
Moses Lake     37  28  38  28  38  30 /  20  10  20  20  10  30
Wenatchee      36  31  37  30  36  31 /  60  10  30  30  10  30
Omak           34  26  34  27  33  28 /  60  30  40  30  10  30

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$




000
FXUS66 KOTX 161807
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1007 AM PST TUE DEC 16 2014

.SYNOPSIS...
A weak storm system will bring light accumulations of snow
today to the areas near the Cascades and light rain or snow to the
western Columbia Basin. A more active weather pattern will
develop late in the week with generally mountain snow and valley
rain or minimally accumulating snow.

&&

.DISCUSSION...
Second update of the morning to add slight chance pops for a
second weather disturbance to work its way up through the forecast
area today and early this evening. Current radar shows the small
counter clockwise rotating circulation producing rain near the
tri- cities area which is expected to de-intesify some through the
day but by later today into the early evening some re-intensification
of the circulation when it is in the vicinity of the Columba
Basin, Spokane, and Washington Palouse area. It quickly falls
apart in the evening per a number of HRRR model runs so the pops
and qpf assigned to it remain small at this point in time.
/Pelatti

&&

.AVIATION...
18Z TAFS: Weak upper level disturbance working its way through the
aviation area this morning. A second weak disturbance that is
smaller is followiong quickly behind and will pass today as well.
So for the most part the precipitation is expect to be rather
light and produce and/or enhance ongoing MVFR ceilings and
visibilites today...but locations nearest very localized higher
intensity precipitation could dip to VFR at times. Overnight the
expecation is these two disturbances will have cleared the area
and fog/low clouds will continue to be an issue. /Pelatti


&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        36  29  38  32  37  31 /  10  20  10  30  30  10
Coeur d`Alene  37  30  40  33  38  31 /  10  20  10  40  40  10
Pullman        40  29  42  32  41  32 /  10  20  10  30  30  10
Lewiston       43  32  42  35  43  34 /   0  10  10  30  30  10
Colville       34  28  36  31  37  31 /  40  30  20  30  30  20
Sandpoint      35  28  36  30  36  31 /  10  20  10  40  40  20
Kellogg        37  30  38  31  36  30 /  10  20  10  40  40  20
Moses Lake     37  28  38  28  38  30 /  20  10  20  20  10  30
Wenatchee      36  31  37  30  36  31 /  60  10  30  30  10  30
Omak           34  26  34  27  33  28 /  60  30  40  30  10  30

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KPQR 161754
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
954 AM PST TUE DEC 16 2014

.SYNOPSIS...SHOWERS WILL DECREASE TODAY AS A WEAK UPPER TROUGH MOVES
NORTHEAST OF THE AREA. AFTER A BRIEF BREAK IN RAIN THIS AFTERNOON AND
EVENING ANOTHER UPPER TROUGH WILL BRING PERIODS OF RAIN...MAINLY TO
THE HIGHER ELEVATIONS TONIGHT AND WEDNESDAY.  A MORE ORGANIZED FRONT
WILL BRING GUSTY WINDS AND LARGE SURF TO THE COAST...AND WIDESPREAD
RAIN THURSDAY NIGHT AND FRIDAY. RISING SNOW LEVELS AND SUBTROPICAL
MOISTURE SPILLING INTO THE REGION WILL LIKELY BRING RAIN TO ALL BUT
THE HIGHEST PEAKS. COLDER AIR WILL MOVE IN BEHIND THE FRONT WITH SOME
SNOW SHOWERS FOR THE CASCADES PASSES POSSIBLE FRIDAY NIGHT AND
SATURDAY BEFORE ANOTHER WARMER SYSTEM RAISES THE SNOW LEVELS AGAIN
LATE IN THE WEEKEND

&&
.UPDATE...SHOWERS ARE QUICKLY MOVING NORTH OVER NW OREGON AND SW
WASHINGTON THIS MORNING AS A LOW IS SPINNING UP OFFSHORE THE NORTHERN
CALIFORNIA COAST. HAVE REMOVED POPS SOUTH OF SALEM FOR THE REST OF
THIS MORNING AND THE EARLY AFTERNOON...AND HAVE REDUCED POPS NORTH OF
SALEM WITH ISOLATED SHOWERS FOR THE INTERIOR VALLEYS AND SCATTERED
SHOWERS FOR THE HIGHER TERRAIN. SATELLITE AND SURFACE OBSERVATIONS
SHOWS PATCHY FOG IN THE INTERIOR VALLEYS OF SOUTHERN LANE
COUNTY...NEAR EUGENE...AND HAVE ADDED FOG IN THE FORECAST FOR THE
REMAINDER OF THE MORNING.

HAVE CONTINUED THE NORTHWARD TREND OF DISAPPEARING RAIN FOR THIS
AFTERNOON AND EVENING BY REMOVING POPS TO THE NORTH. HOWEVER...THE
POPS AT THIS TIME ARE REINTRODUCED TO THE SOUTH DUE TO THE LOW
SHIFTING INLAND. THE SNOW LEVEL IS AROUND 4000 FT THIS MORNING WITH
WEB CAMS SUGGESTING 1 TO 2 INCHES OF ACCUMULATING SNOW FOR THE CASCADE
PASSES OVERNIGHT.

SATELLITE IMAGERY IS SHOWING CYCLOGENESIS AROUND 200 MILES OFFSHORE OF
THE CALIFORNIA/OREGON BORDER THIS MORNING. THIS LOW MAY BE SLIGHTLY
DEEPER THAN THE PREVIOUS MODELS SUGGESTED AND EXPECT THE EASTERLY
SURFACE PRESSURE GRADIENT TO HANG ON A LITTLE LONGER. THE EASTERLY
WINDS WILL WEAKEN A LITTLE THIS MORNING AND AFTERNOON THAN INCREASE
AGAIN LATE THIS AFTERNOON AND EVENING. THE GRADIENT WILL NOT BE
PARTICULARLY STRONG WITH MODELS FORECASTING A TROUTDALE TO DALLES
GRADIENT AROUND 8 MB...BUT THIS IS STRONGER THAN THE PREVIOUS
FORECAST AND HAVE INCREASED THE EASTERLY WINDS FOR TONIGHT THROUGH
WED MORNING...MAINLY THROUGH THE COLUMBIA RIVER GORGE AND NORTHERN
AREAS. THE DEEPER LOW WILL ALSO RESULT IN A TIGHTER SOUTHERLY
GRADIENT WED AFTERNOON AS THE LOW MOVES INLAND AND HAVE INCREASED THE
SOUTHERLY WINDS FOR THE WILLAMETTE VALLEY A TAD.

THE UPPER TROUGH ASSOCIATED WITH THE FRONT/LOW OFFSHORE IS SPLITTING
AND RAIN FOR TONIGHT AND WEDNESDAY ACROSS NW OREGON AND SW WASHINGTON
IS NOT VERY IMPRESSIVE. MOST OF THE RAIN WILL BE FAR SOUTH OR FAR
NORTH OF US...BUT A PART OF THE UPPER TROUGH WILL APPROACH TONIGHT
AND MOVE OVER WEDNESDAY...MAINTAINING A CHANCE OF SHOWERS. THINK
MOST OF THESE SHOWERS WILL BE OVER THE HIGHER TERRAIN WITH THE
INTERIOR VALLEYS NOT SEEING MUCH RAIN. TJ

.PREVIOUS SHORT TERM...TODAY THROUGH FRIDAY...LIGHT RAIN PERSISTS
TODAY AS A WEAK FRONTAL SYSTEM CONTINUES TO PUSH EAST OF THE FORECAST
AREA EARLY THIS MORNING. SURFACE OBSERVATIONS ARE REPORTING BETWEEN
0.01-0.05" OF RAIN IN THE PAST 6 HOURS...EXCEPT FOR ALMOST 0.10" OF
PRECIP OVER THE COAST RANGE. THE NEXT FRONTAL SYSTEM CAN BE SEEN IN
INFRARED SATELLITE IMAGERY JUST OFF THE OREGON/CALIFORNIA COASTLINE
THIS MORNING. TEMPERATURES HAVE LOWERED TO 32-35 DEG F IN THE UPPER
PORTIONS OF THE HOOD RIVER VALLEY...WHERE SOME LIGHT SNOW
ACCUMULATIONS UP TO AN INCH OR SO ARE POSSIBLE THROUGH THIS MORNING.

EVEN WITH OFFSHORE FLOW PERSISTING...MODELS CONTINUE TO SHOW THE
EASTERLY GRADIENT STARTING TO SLACK OFF TODAY. GRADIENTS FURTHER
WEAKEN THROUGH LATE WED...AS HIGH PRESSURE SLOWLY WEAKENS EAST OF THE
CASCADES.

MODELS REMAIN CONSISTENT IN SHOWING MUCH OF THE ENERGY ASSOCIATED
WITH THIS NEXT LOW PRES SYSTEM HEADING SOUTH INTO NORTHERN CALIFORNIA
LATER TODAY. AS A RESULT...OFFSHORE LOW LEVEL FLOW BECOMES REINFORCED
WHILE FLOW ALOFT TURNS A BIT MORE SOUTHERLY...ALLOWING SHOWER
ACTIVITY TO DIMINISH BY THIS AFTERNOON. SHOWERS MAY LINGER LONGER
ALONG THE CENTRAL OREGON COAST THOUGH. MOISTURE BEGINS TO SPREAD
ACROSS THE AREA AS THE CENTER OF THE LOW PRES DRIFTS TOWARDS THE
OREGON/CALIFORNIA BORDER OVERNIGHT TONIGHT INTO WEDNESDAY MORNING.
THE UPPER LEVEL TROUGH AXIS MOVES INLAND MIDDAY WEDNESDAY AND
WEDNESDAY NIGHT... WHICH SHOULD BRING ANOTHER ROUND OF PRECIP TO THE
AREA. BRIEF UPPER LEVEL RIDGING DEVELOPS FOR THURSDAY...BUT A WARM
FRONT AHEAD OF THE NEXT ORGANIZED FRONTAL BAND COULD BRING A THREAT
FOR PRECIP BY EARLY THURSDAY AFTERNOON. EAST WINDS MAY PICK UP AGAIN
THROUGH THE GORGE AS THIS SYSTEM APPROACHES THE COAST. THIS STRONG
FRONTAL SYSTEM PUSHES INTO THE PACIFIC NORTHWEST FRIDAY...BRINGING A
DECENT BATCH OF PRECIP TO THE AREA AS WELL AS GUSTY SOUTH WINDS FOR
THE COAST.

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...FRIDAY NIGHT
THROUGH MONDAY...A COLD AIR UNSTABLE AIRMASS WILL FOLLOW A STRONG
FRONTAL SYSTEM AND KEEP SHOWERS GOING INTO FRIDAY NIGHT. SNOW LEVELS
SHOULD LOWER TO NEAR 4000 FT ON SO ACCUMULATING SNOW APPEARS LIKELY
FOR AT LEAST THE HIGHER PASSES. AN ADDITIONAL SHORTWAVE TROUGH OR TWO
COULD ENHANCE SHOWER ACTIVITY EARLY IN THE WEEKEND AND BRING MUCH
NEEDED SNOW TO THE HIGHER CASCADES.

MODELS GENERALLY AGREE SNOW LEVELS WILL RISE LATE IN THE WEEKEND AS A
WARM FRONT SLIDES INTO THE REGION. STRONG ZONAL FLOW WILL FOCUS
PERSISTENT AND HEAVIER RAIN ACROSS SOUTHWEST BRITISH COLUMBIA AND
WESTERN WASHINGTON LATE IN THE WEEKEND AND EARLY NEXT WEEK. FOR
NOW...IT APPEARS THE BULK OF THE HEAVIEST RAIN WILL REMAIN NORTH OF
OUR REGION...AND WHEN HEAVIER PRECIPITATION ARRIVES...IT WILL REMAIN
TRANSIENT ENOUGH ACROSS OUR FORECAST AREA TO MINIMIZE FLOOD
CONCERNS. NONETHELESS...THIS PATTERN CERTAINLY BEARS
WATCHING...PARTICULARLY ACROSS THE NORTHERN HALF OF THE FORECAST
AREA WHERE A SLIGHT SHIFT IN THE STORM TRACK COULD PUT US IN THE
PATH OF A MODEST FIRE HOSE AND FLOOD CONCERNS WILL RISE. /NEUMAN


&&


.AVIATION...MAINLY VFR CONDITIONS TODAY IN LIGHT TO MODERATE
OFFSHORE FLOW ACROSS FORECAST AREA. A FEW EXCEPTIONS THIS
MORNING...SOME LINGERING MVFR NEAR KAST AND SOME FOG IN THE
WILLAMETTE VALLEY SOUTH OF KCVO. ALSO EASTERLY UPSLOPE FLOW
CAUSING MOUNTAIN OBSCURATIONS ALONG THE EAST SLOPES AND CREST OF
THE CASCADES.

THE MVFR CIGS NEAR KAST SHOULD LIFT AS THE FRONTAL ZONE WHICH
BROUGHT -RA EARLY THIS MORNING CONTINUES TO DRIFT NORTH INTO
WASHINGTON. AS FOR THE LIFR/VLIFR CONDITIONS AROUND KEUG... THEY
WILL PROBABLY BE MORE STUBBORN AS LOW PRESSURE OFF THE NORTHERN CA
COAST CONTINUES TO PULL IN LIGHT N-NE FLOW...JAMMING LOW CLOUDS
AGAINST THE SOUTH END OF THE WILLAMETTE VALLEY. SUSPECT IT WILL
LIFT TO REGULAR IFR WITH CIGS ABOVE 500 FT BY MIDDAY...BUT WILL
PROBABLY DROP BACK DOWN TO NEAR THE DECK LATER TONIGHT AS -RA
REDEVELOPS WITH OUR NEXT FRONTAL SYSTEM.

KPDX AND APPROACHES...VFR CONDITIONS WITH CIGS BETWEEN 4K TO 6K
FT THIS MORNING RISING TO AROUND 12K FT THIS AFTERNOON. LIGHT TO
MODERATE EAST SFC WINDS THROUGH THIS EVENING.  WEAGLE

&&

.MARINE...SATELLITE IMAGERY THIS MORNING SHOWS A WELL-DEFINED LOW
PRESSURE SYSTEM ABOUT 200 NM WEST OF CRESCENT CITY CA. THIS
SYSTEM APPEARS TO HAVE STRENGTHENED TO AROUND 995 MB BASED ON
SATELLITE ANALYSIS AND THE MAGNITUDE OF WINDS ASSOCIATED WITH THE
LOW. MODELS APPEAR TO BE INITIALIZING THIS LOW TOO WEAKLY...EVEN
THE 16Z RAP ONLY SHOWS A 1000 MB LOW IN THIS LOCATION. RAPIDSCAT
IMAGERY FROM ABOARD THE INTERNATIONAL SPACE STATION SHOWS
SATELLITE-DERIVED WINDS OF UP TO 40 KT IN SE QUADRANT OF THIS
LOW...AND BUOY 46002 IS GUSTING TO GALE FORCE IN THE NW QUADRANT
OF THE LOW. THIS SYSTEM WILL NEED TO BE WATCHED CLOSELY AS IT
DRIFTS NE TOWARD OREGON THE NEXT 24-36 HRS. HOWEVER IT APPEARS THE
LOW IS APPROACHING ITS MAXIMUM STRENGTH AND WILL LIKELY START
WEAKENING AS MODELS SUGGEST BY TONIGHT. THEREFORE WE DID NOT
DEVIATE TOO FAR FROM THE MODELS WITH OUR WIND/SWELL FORECAST IN
THE NEXT 1-2 DAYS.

THE NEXT RELATIVELY STRONG FRONTAL SYSTEM IS BEGINNING TO TAKE
SHAPE BETWEEN 150W-160W...AND MAY PRODUCE GALES FOR OUR WATERS AS
IT MOVES ONSHORE LATER THU/EARLY FRI. THERE IS A GOOD POTENTIAL
FOR COASTAL JET FORMATION WHICH WOULD ENHANCE WINDS JUST AHEAD OF
THE FRONT WITH GUSTS TO 45 KT POSSIBLE NEAR THE COAST THU NIGHT.
ENP GUIDANCE SUGGESTS A SOLID 16-20 FT SWELL WITH A DOMINANT
PERIOD OF 16-20 SECONDS FOLLOWS THE FRONT...POSSIBLY ENOUGH TO
WARRANT A HIGH SURF ADVISORY FRIDAY.  WEAGLE

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL NOON PST TODAY FOR WATERS
     FROM CAPE SHOALWATER WA TO CASCADE HEAD OR FROM 10 TO 60 NM-
     WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL NOON PST TODAY
     FOR COASTAL WATERS FROM CASCADE HEAD TO FLORENCE OR OUT 10 NM-
     WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR FROM 10
     TO 60 NM-WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO
     60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 2 PM
     PST THIS AFTERNOON.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 11 PM
     THIS EVENING TO 3 AM PST WEDNESDAY.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.




000
FXUS66 KPQR 161754
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
954 AM PST TUE DEC 16 2014

.SYNOPSIS...SHOWERS WILL DECREASE TODAY AS A WEAK UPPER TROUGH MOVES
NORTHEAST OF THE AREA. AFTER A BRIEF BREAK IN RAIN THIS AFTERNOON AND
EVENING ANOTHER UPPER TROUGH WILL BRING PERIODS OF RAIN...MAINLY TO
THE HIGHER ELEVATIONS TONIGHT AND WEDNESDAY.  A MORE ORGANIZED FRONT
WILL BRING GUSTY WINDS AND LARGE SURF TO THE COAST...AND WIDESPREAD
RAIN THURSDAY NIGHT AND FRIDAY. RISING SNOW LEVELS AND SUBTROPICAL
MOISTURE SPILLING INTO THE REGION WILL LIKELY BRING RAIN TO ALL BUT
THE HIGHEST PEAKS. COLDER AIR WILL MOVE IN BEHIND THE FRONT WITH SOME
SNOW SHOWERS FOR THE CASCADES PASSES POSSIBLE FRIDAY NIGHT AND
SATURDAY BEFORE ANOTHER WARMER SYSTEM RAISES THE SNOW LEVELS AGAIN
LATE IN THE WEEKEND

&&
.UPDATE...SHOWERS ARE QUICKLY MOVING NORTH OVER NW OREGON AND SW
WASHINGTON THIS MORNING AS A LOW IS SPINNING UP OFFSHORE THE NORTHERN
CALIFORNIA COAST. HAVE REMOVED POPS SOUTH OF SALEM FOR THE REST OF
THIS MORNING AND THE EARLY AFTERNOON...AND HAVE REDUCED POPS NORTH OF
SALEM WITH ISOLATED SHOWERS FOR THE INTERIOR VALLEYS AND SCATTERED
SHOWERS FOR THE HIGHER TERRAIN. SATELLITE AND SURFACE OBSERVATIONS
SHOWS PATCHY FOG IN THE INTERIOR VALLEYS OF SOUTHERN LANE
COUNTY...NEAR EUGENE...AND HAVE ADDED FOG IN THE FORECAST FOR THE
REMAINDER OF THE MORNING.

HAVE CONTINUED THE NORTHWARD TREND OF DISAPPEARING RAIN FOR THIS
AFTERNOON AND EVENING BY REMOVING POPS TO THE NORTH. HOWEVER...THE
POPS AT THIS TIME ARE REINTRODUCED TO THE SOUTH DUE TO THE LOW
SHIFTING INLAND. THE SNOW LEVEL IS AROUND 4000 FT THIS MORNING WITH
WEB CAMS SUGGESTING 1 TO 2 INCHES OF ACCUMULATING SNOW FOR THE CASCADE
PASSES OVERNIGHT.

SATELLITE IMAGERY IS SHOWING CYCLOGENESIS AROUND 200 MILES OFFSHORE OF
THE CALIFORNIA/OREGON BORDER THIS MORNING. THIS LOW MAY BE SLIGHTLY
DEEPER THAN THE PREVIOUS MODELS SUGGESTED AND EXPECT THE EASTERLY
SURFACE PRESSURE GRADIENT TO HANG ON A LITTLE LONGER. THE EASTERLY
WINDS WILL WEAKEN A LITTLE THIS MORNING AND AFTERNOON THAN INCREASE
AGAIN LATE THIS AFTERNOON AND EVENING. THE GRADIENT WILL NOT BE
PARTICULARLY STRONG WITH MODELS FORECASTING A TROUTDALE TO DALLES
GRADIENT AROUND 8 MB...BUT THIS IS STRONGER THAN THE PREVIOUS
FORECAST AND HAVE INCREASED THE EASTERLY WINDS FOR TONIGHT THROUGH
WED MORNING...MAINLY THROUGH THE COLUMBIA RIVER GORGE AND NORTHERN
AREAS. THE DEEPER LOW WILL ALSO RESULT IN A TIGHTER SOUTHERLY
GRADIENT WED AFTERNOON AS THE LOW MOVES INLAND AND HAVE INCREASED THE
SOUTHERLY WINDS FOR THE WILLAMETTE VALLEY A TAD.

THE UPPER TROUGH ASSOCIATED WITH THE FRONT/LOW OFFSHORE IS SPLITTING
AND RAIN FOR TONIGHT AND WEDNESDAY ACROSS NW OREGON AND SW WASHINGTON
IS NOT VERY IMPRESSIVE. MOST OF THE RAIN WILL BE FAR SOUTH OR FAR
NORTH OF US...BUT A PART OF THE UPPER TROUGH WILL APPROACH TONIGHT
AND MOVE OVER WEDNESDAY...MAINTAINING A CHANCE OF SHOWERS. THINK
MOST OF THESE SHOWERS WILL BE OVER THE HIGHER TERRAIN WITH THE
INTERIOR VALLEYS NOT SEEING MUCH RAIN. TJ

.PREVIOUS SHORT TERM...TODAY THROUGH FRIDAY...LIGHT RAIN PERSISTS
TODAY AS A WEAK FRONTAL SYSTEM CONTINUES TO PUSH EAST OF THE FORECAST
AREA EARLY THIS MORNING. SURFACE OBSERVATIONS ARE REPORTING BETWEEN
0.01-0.05" OF RAIN IN THE PAST 6 HOURS...EXCEPT FOR ALMOST 0.10" OF
PRECIP OVER THE COAST RANGE. THE NEXT FRONTAL SYSTEM CAN BE SEEN IN
INFRARED SATELLITE IMAGERY JUST OFF THE OREGON/CALIFORNIA COASTLINE
THIS MORNING. TEMPERATURES HAVE LOWERED TO 32-35 DEG F IN THE UPPER
PORTIONS OF THE HOOD RIVER VALLEY...WHERE SOME LIGHT SNOW
ACCUMULATIONS UP TO AN INCH OR SO ARE POSSIBLE THROUGH THIS MORNING.

EVEN WITH OFFSHORE FLOW PERSISTING...MODELS CONTINUE TO SHOW THE
EASTERLY GRADIENT STARTING TO SLACK OFF TODAY. GRADIENTS FURTHER
WEAKEN THROUGH LATE WED...AS HIGH PRESSURE SLOWLY WEAKENS EAST OF THE
CASCADES.

MODELS REMAIN CONSISTENT IN SHOWING MUCH OF THE ENERGY ASSOCIATED
WITH THIS NEXT LOW PRES SYSTEM HEADING SOUTH INTO NORTHERN CALIFORNIA
LATER TODAY. AS A RESULT...OFFSHORE LOW LEVEL FLOW BECOMES REINFORCED
WHILE FLOW ALOFT TURNS A BIT MORE SOUTHERLY...ALLOWING SHOWER
ACTIVITY TO DIMINISH BY THIS AFTERNOON. SHOWERS MAY LINGER LONGER
ALONG THE CENTRAL OREGON COAST THOUGH. MOISTURE BEGINS TO SPREAD
ACROSS THE AREA AS THE CENTER OF THE LOW PRES DRIFTS TOWARDS THE
OREGON/CALIFORNIA BORDER OVERNIGHT TONIGHT INTO WEDNESDAY MORNING.
THE UPPER LEVEL TROUGH AXIS MOVES INLAND MIDDAY WEDNESDAY AND
WEDNESDAY NIGHT... WHICH SHOULD BRING ANOTHER ROUND OF PRECIP TO THE
AREA. BRIEF UPPER LEVEL RIDGING DEVELOPS FOR THURSDAY...BUT A WARM
FRONT AHEAD OF THE NEXT ORGANIZED FRONTAL BAND COULD BRING A THREAT
FOR PRECIP BY EARLY THURSDAY AFTERNOON. EAST WINDS MAY PICK UP AGAIN
THROUGH THE GORGE AS THIS SYSTEM APPROACHES THE COAST. THIS STRONG
FRONTAL SYSTEM PUSHES INTO THE PACIFIC NORTHWEST FRIDAY...BRINGING A
DECENT BATCH OF PRECIP TO THE AREA AS WELL AS GUSTY SOUTH WINDS FOR
THE COAST.

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...FRIDAY NIGHT
THROUGH MONDAY...A COLD AIR UNSTABLE AIRMASS WILL FOLLOW A STRONG
FRONTAL SYSTEM AND KEEP SHOWERS GOING INTO FRIDAY NIGHT. SNOW LEVELS
SHOULD LOWER TO NEAR 4000 FT ON SO ACCUMULATING SNOW APPEARS LIKELY
FOR AT LEAST THE HIGHER PASSES. AN ADDITIONAL SHORTWAVE TROUGH OR TWO
COULD ENHANCE SHOWER ACTIVITY EARLY IN THE WEEKEND AND BRING MUCH
NEEDED SNOW TO THE HIGHER CASCADES.

MODELS GENERALLY AGREE SNOW LEVELS WILL RISE LATE IN THE WEEKEND AS A
WARM FRONT SLIDES INTO THE REGION. STRONG ZONAL FLOW WILL FOCUS
PERSISTENT AND HEAVIER RAIN ACROSS SOUTHWEST BRITISH COLUMBIA AND
WESTERN WASHINGTON LATE IN THE WEEKEND AND EARLY NEXT WEEK. FOR
NOW...IT APPEARS THE BULK OF THE HEAVIEST RAIN WILL REMAIN NORTH OF
OUR REGION...AND WHEN HEAVIER PRECIPITATION ARRIVES...IT WILL REMAIN
TRANSIENT ENOUGH ACROSS OUR FORECAST AREA TO MINIMIZE FLOOD
CONCERNS. NONETHELESS...THIS PATTERN CERTAINLY BEARS
WATCHING...PARTICULARLY ACROSS THE NORTHERN HALF OF THE FORECAST
AREA WHERE A SLIGHT SHIFT IN THE STORM TRACK COULD PUT US IN THE
PATH OF A MODEST FIRE HOSE AND FLOOD CONCERNS WILL RISE. /NEUMAN


&&


.AVIATION...MAINLY VFR CONDITIONS TODAY IN LIGHT TO MODERATE
OFFSHORE FLOW ACROSS FORECAST AREA. A FEW EXCEPTIONS THIS
MORNING...SOME LINGERING MVFR NEAR KAST AND SOME FOG IN THE
WILLAMETTE VALLEY SOUTH OF KCVO. ALSO EASTERLY UPSLOPE FLOW
CAUSING MOUNTAIN OBSCURATIONS ALONG THE EAST SLOPES AND CREST OF
THE CASCADES.

THE MVFR CIGS NEAR KAST SHOULD LIFT AS THE FRONTAL ZONE WHICH
BROUGHT -RA EARLY THIS MORNING CONTINUES TO DRIFT NORTH INTO
WASHINGTON. AS FOR THE LIFR/VLIFR CONDITIONS AROUND KEUG... THEY
WILL PROBABLY BE MORE STUBBORN AS LOW PRESSURE OFF THE NORTHERN CA
COAST CONTINUES TO PULL IN LIGHT N-NE FLOW...JAMMING LOW CLOUDS
AGAINST THE SOUTH END OF THE WILLAMETTE VALLEY. SUSPECT IT WILL
LIFT TO REGULAR IFR WITH CIGS ABOVE 500 FT BY MIDDAY...BUT WILL
PROBABLY DROP BACK DOWN TO NEAR THE DECK LATER TONIGHT AS -RA
REDEVELOPS WITH OUR NEXT FRONTAL SYSTEM.

KPDX AND APPROACHES...VFR CONDITIONS WITH CIGS BETWEEN 4K TO 6K
FT THIS MORNING RISING TO AROUND 12K FT THIS AFTERNOON. LIGHT TO
MODERATE EAST SFC WINDS THROUGH THIS EVENING.  WEAGLE

&&

.MARINE...SATELLITE IMAGERY THIS MORNING SHOWS A WELL-DEFINED LOW
PRESSURE SYSTEM ABOUT 200 NM WEST OF CRESCENT CITY CA. THIS
SYSTEM APPEARS TO HAVE STRENGTHENED TO AROUND 995 MB BASED ON
SATELLITE ANALYSIS AND THE MAGNITUDE OF WINDS ASSOCIATED WITH THE
LOW. MODELS APPEAR TO BE INITIALIZING THIS LOW TOO WEAKLY...EVEN
THE 16Z RAP ONLY SHOWS A 1000 MB LOW IN THIS LOCATION. RAPIDSCAT
IMAGERY FROM ABOARD THE INTERNATIONAL SPACE STATION SHOWS
SATELLITE-DERIVED WINDS OF UP TO 40 KT IN SE QUADRANT OF THIS
LOW...AND BUOY 46002 IS GUSTING TO GALE FORCE IN THE NW QUADRANT
OF THE LOW. THIS SYSTEM WILL NEED TO BE WATCHED CLOSELY AS IT
DRIFTS NE TOWARD OREGON THE NEXT 24-36 HRS. HOWEVER IT APPEARS THE
LOW IS APPROACHING ITS MAXIMUM STRENGTH AND WILL LIKELY START
WEAKENING AS MODELS SUGGEST BY TONIGHT. THEREFORE WE DID NOT
DEVIATE TOO FAR FROM THE MODELS WITH OUR WIND/SWELL FORECAST IN
THE NEXT 1-2 DAYS.

THE NEXT RELATIVELY STRONG FRONTAL SYSTEM IS BEGINNING TO TAKE
SHAPE BETWEEN 150W-160W...AND MAY PRODUCE GALES FOR OUR WATERS AS
IT MOVES ONSHORE LATER THU/EARLY FRI. THERE IS A GOOD POTENTIAL
FOR COASTAL JET FORMATION WHICH WOULD ENHANCE WINDS JUST AHEAD OF
THE FRONT WITH GUSTS TO 45 KT POSSIBLE NEAR THE COAST THU NIGHT.
ENP GUIDANCE SUGGESTS A SOLID 16-20 FT SWELL WITH A DOMINANT
PERIOD OF 16-20 SECONDS FOLLOWS THE FRONT...POSSIBLY ENOUGH TO
WARRANT A HIGH SURF ADVISORY FRIDAY.  WEAGLE

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL NOON PST TODAY FOR WATERS
     FROM CAPE SHOALWATER WA TO CASCADE HEAD OR FROM 10 TO 60 NM-
     WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL NOON PST TODAY
     FOR COASTAL WATERS FROM CASCADE HEAD TO FLORENCE OR OUT 10 NM-
     WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR FROM 10
     TO 60 NM-WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO
     60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 2 PM
     PST THIS AFTERNOON.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 11 PM
     THIS EVENING TO 3 AM PST WEDNESDAY.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.



000
FXUS66 KOTX 161730
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
929 AM PST TUE DEC 16 2014

.SYNOPSIS...
A weak storm system will bring light accumulations of snow
today to the areas near the Cascades and light rain or snow to the
western Columbia Basin. A more active weather pattern will
develop late in the week with generally mountain snow and valley
rain or minimally accumulating snow.

&&

.DISCUSSION...

Updates to this mornings forecast to add mention of very light
freezing rain to the Spokane area and vicinity as the upper air
sounding hints that there is likely to be a crossover temperature
at the top of the inversion at roughly 880mb to near +3 Celsius
atop the colder freezing layer below it this morning. That along
with most ground temperatures running below freezing made it a
reasonable addition. Little to no accumulation of snow or freezing
rain is included with the addition and generally valid wording for
most locations east of a Ritzville to Republic line. Those to the
west are either to remain snow or have warmed up enough already to
just call it rain, but there could be a few small pockets or two
this morning of a wintry mix there as well but pops are larger
with expectation that up-slope process gives those locations a
greater likelihood of receiving measurable precipitation. /Pelatti

&&

.AVIATION...
18Z TAFS: Weak upper level disturbance working its way through the
aviation area this morning. A second weak disturbance that is
smaller is followiong quickly behind and will pass today as well.
So for the most part the precipitation is expect to be rather
light and produce and/or enhance ongoing MVFR ceilings and
visibilites today...but locations nearest very localized higher
intensity precipitation could dip to VFR at times. Overnight the
expecation is these two disturbances will have cleared the area
and fog/low clouds will continue to be an issue. /Pelatti

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        36  29  38  32  37  31 /  10  10  10  30  30  10
Coeur d`Alene  37  30  40  33  38  31 /  10  10  10  40  40  10
Pullman        40  29  42  32  41  32 /  10  10  10  30  30  10
Lewiston       43  32  42  35  43  34 /  20  10  10  30  30  10
Colville       34  28  36  31  37  31 /  40  30  20  30  30  20
Sandpoint      35  28  36  30  36  31 /  10  20  10  40  40  20
Kellogg        37  30  38  31  36  30 /  10  20  10  40  40  20
Moses Lake     37  28  38  28  38  30 /  60  10  20  20  10  30
Wenatchee      36  31  37  30  36  31 /  70  10  30  30  10  30
Omak           34  26  34  27  33  28 /  60  30  40  30  10  30

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 161730
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
929 AM PST TUE DEC 16 2014

.SYNOPSIS...
A weak storm system will bring light accumulations of snow
today to the areas near the Cascades and light rain or snow to the
western Columbia Basin. A more active weather pattern will
develop late in the week with generally mountain snow and valley
rain or minimally accumulating snow.

&&

.DISCUSSION...

Updates to this mornings forecast to add mention of very light
freezing rain to the Spokane area and vicinity as the upper air
sounding hints that there is likely to be a crossover temperature
at the top of the inversion at roughly 880mb to near +3 Celsius
atop the colder freezing layer below it this morning. That along
with most ground temperatures running below freezing made it a
reasonable addition. Little to no accumulation of snow or freezing
rain is included with the addition and generally valid wording for
most locations east of a Ritzville to Republic line. Those to the
west are either to remain snow or have warmed up enough already to
just call it rain, but there could be a few small pockets or two
this morning of a wintry mix there as well but pops are larger
with expectation that up-slope process gives those locations a
greater likelihood of receiving measurable precipitation. /Pelatti

&&

.AVIATION...
18Z TAFS: Weak upper level disturbance working its way through the
aviation area this morning. A second weak disturbance that is
smaller is followiong quickly behind and will pass today as well.
So for the most part the precipitation is expect to be rather
light and produce and/or enhance ongoing MVFR ceilings and
visibilites today...but locations nearest very localized higher
intensity precipitation could dip to VFR at times. Overnight the
expecation is these two disturbances will have cleared the area
and fog/low clouds will continue to be an issue. /Pelatti

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        36  29  38  32  37  31 /  10  10  10  30  30  10
Coeur d`Alene  37  30  40  33  38  31 /  10  10  10  40  40  10
Pullman        40  29  42  32  41  32 /  10  10  10  30  30  10
Lewiston       43  32  42  35  43  34 /  20  10  10  30  30  10
Colville       34  28  36  31  37  31 /  40  30  20  30  30  20
Sandpoint      35  28  36  30  36  31 /  10  20  10  40  40  20
Kellogg        37  30  38  31  36  30 /  10  20  10  40  40  20
Moses Lake     37  28  38  28  38  30 /  60  10  20  20  10  30
Wenatchee      36  31  37  30  36  31 /  70  10  30  30  10  30
Omak           34  26  34  27  33  28 /  60  30  40  30  10  30

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$




000
FXUS66 KSEW 161719
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 AM PST TUE DEC 16 2014

.SYNOPSIS...WEAKENING WEATHER SYSTEMS TODAY AND WEDNESDAY ARE
EXPECTED TO PRODUCE SPOTTY LIGHT RAIN IN WESTERN WASHINGTON. A
STRONGER PACIFIC FRONTAL SYSTEM IS FORECAST TO ARRIVE LATER THURSDAY
INTO FRIDAY FOR MORE RAIN WITH ANOTHER SYSTEM FOLLOWING OVER THE
WEEKEND.
&&

.SHORT TERM...WV SATELLITE IMAGERY SHOWS A VERY DISTINCT SPLIT IN
THE UPPER AIR PATTERN ALONG THE W COAST. A LOW IS FORMING ON THE SRN
EXTENT OF AN APPROACHING FRONT WITH THE BULK OF ENERGY AND MOISTURE
DRIVING TOWARD CA. THE WEAKER NRN BRANCH OF THE JET WILL BRING
WEAKER LIFT AND MOISTURE ABOVE 925 MB. LOW LEVEL GRADIENTS WILL
INHIBIT SATURATION NEAR THE SURFACE SO PRECIPITATION AMOUNTS TODAY
WILL BE LIGHT AND SPOTTY. CURRENT RADAR LOOP IS SHOWING SOME LIGHT
RAIN JUST NOW PUSHING INTO PUGET SOUND. AS THIS BATCH OF LIGHT RAIN
MOVES THROUGH BY AFTERNOON...DRIER WEATHER WILL DEVELOP. BY
TONIGHT...ANY LIGHT LIGHT RAIN SHOULD BE CONFINED TO THE COAST AND
MOUNTAINS.

A TRAILING NRN STREAM SYSTEM WILL MOVE THROUGH THE AREA ON
WEDNESDAY. THIS WILL BE A SIMILAR TYPE SYSTEM WITH LOW QPF AMOUNTS
SHOWN BY MODELS. LIKELY POPS COAST AND MOUNTAINS WITH CHANCE POPS
OVER MOST THE INTERIOR LOWLANDS APPEARS REASONABLE. IT WILL REMAIN
COOL AND CLOUDY WITH HIGHS IN THE MID/UPPER 40S.

UPPER LEVEL HIGH PRESSURE WILL TRAVERSE THE AREA THURSDAY ACCORDING
TO THE GFS AND ECMWF. THE CANADIAN MODEL IS MUCH FASTER WITH THE
NEXT WETTER SYSTEM AND SPREADS RAIN INTO WRN WA BY 18Z THURSDAY. THE
ECMWF SHOWS RAIN BY LATE IN THE DAY AND THE GFS HOLDING OFF UNTIL
THURSDAY NIGHT. WILL LEAVE CHANCE POPS IN PLACE GIVEN THE MODELS
DISCREPANCY. WILL LOOK AT THE NEW 12Z RUNS BEFORE ANY MAKING ANY
ADJUSTMENTS WITH THE AFTERNOON FORECAST PACKAGE.  MERCER

.LONG TERM...NO UPDATE FROM PREVIOUS DISCUSSION...THE FRONTAL SYSTEM
MOVES ONSHORE BY FRIDAY MORNING WITH RAIN TURNING TO SHOWERS. BY
THIS TIME...THE JET HAS RETURNED TO OUR LATITUDE VS CALIFORNIA. A
SHORTWAVE RIDGE AHEAD OF THE NEXT TROUGH BUILDS ONSHORE SATURDAY
BEFORE THE NEXT PACIFIC FRONTAL SYSTEM ARRIVES BY SUNDAY.
AGAIN...PROG TIMING DIFFERS HERE. BUT THE DRIER DAY OVER THE WEEKEND
APPEARS TO BE SATURDAY.

PREVIOUS GUIDANCE OFFERED A PRETTY WET PERIOD SUNDAY INTO MONDAY.
CURRENT GUIDANCE HAS BACKED OFF TO SOME DEGREE. THIS SITUATION BEARS
WATCHING FOR NOW. ALSO KEEPING AN EYE ON A POSSIBLE KONA LOW THAT
WOULD CHANGE THE AMPLITUDE OF THE NORTHERN HEMISPHERE FLOW PATTERN
AND OFFER COOLER AIR FOR THE PACIFIC NW AND PERHAPS SOME SNOW FOR
THE SNOW STARVED MOUNTAINS IN THE LONGER RANGE. STAY TUNED HERE.
BUEHNER

&&

.HYDROLOGY...RIVER FLOODING IS NOT EXPECTED THROUGH AT LEAST
SATURDAY. A WETTER AND WARMER PATTERN WILL PROBABLY DEVELOP SUNDAY
AND MONDAY...AND SOME GUIDANCE SUGGESTING ENOUGH RAIN FOR A THREAT
OF FLOODING ON SOME OF THE MOST FLOOD-PRONE RIVERS. THE LATEST
GUIDANCE IS NOT QUITE AS WET AS PREVIOUS THOUGH. BUEHNER/MERCER

&&

.AVIATION...AN UPPER LEVEL TROUGH OVER THE OFFSHORE WATERS COMBINED
WITH HIGH PRES WELL EAST OF THE AREA IS GIVING LIGHT S FLOW ALOFT.
AT THE SURFACE...HIGH PRES E OF THE CASCADES COMBINED WITH A TROUGH
OF LOW PRES OFFSHORE IS GIVING LOW LEVEL OFFSHORE FLOW. THE AIR MASS
IS MOIST AND STABLE...EXCEPT IS DRY AT LOW LEVELS OVER THE INTERIOR
VALLEYS.

DESPITE ABUNDANT CLOUD COVER AND LIGHT PRECIPITATION...LOW LEVEL
OFFSHORE FLOW IS GIVING VFR CONDITIONS TO THE INTERIOR OF WESTERN
WASHINGTON THIS MORNING WITH GOOD VISIBILITY AND CIGS AROUND FLIGHT
LEVEL 040. MARGINAL VFR CEILINGS AND VISIBILITIES ARE OCCURRING
ALONG THE COAST WHERE PRECIPITATION RATES ARE HEAVIER AND CLOUD
BASES ARE FL 025-030. THE 12 KM NAM SOLUTION SHOWS LITTLE CHANGE IN
THE OVERALL PATTERN THROUGH ABOUT 07Z THIS EVENING FOLLOWED BY SOME
IMPROVEMENT TONIGHT AND WEDNESDAY MORNING BETWEEN THE INCOMING SPLIT
TROUGH AND THE NEXT ONE THAT ARRIVES WED NIGHT. THE 4 KM HRRR SHOWS
THE IMPROVEMENT TAKING PLACE FASTER...THIS AFTERNOON IN THE INTERIOR
SPREADING TO THE COAST OVERNIGHT. THE COASTAL RADAR SUGGESTS THAT
THE TYPICALLY SUPERIOR HRRR MAY BE A BIT FAST WITH ITS TIMING. THE
18Z TERMINALS WILL SPLIT THE DIFFERENCE. ALBRECHT

KSEA...VFR CONDITIONS WILL CONTINUE WITH BKN-OVC040 OVC060 AND
PERIODS OF VERY LIGHT RAIN AND VISIBILITIES 6KM OR HIGHER. EAST TO
SOUTHEAST WIND 5-9 KT. ALBRECHT

&&

.MARINE...HIGH PRES E OF THE CASCADES COMBINED WITH A TROUGH OF LOW
PRES OVER THE OFFSHORE WATERS IS GIVING OFFSHORE FLOW TO THE AREA
THIS MORNING. THIS OFFSHORE FLOW WILL GRADUALLY EASE LATER THIS
AFTERNOON AS THE OFFSHORE TROUGH MOVES ONSHORE AND WEAKENS. SMALL
CRAFT ADVISORY CONDITIONS WILL CONTINUE OVER THE COASTAL ZONES
THROUGH THIS AFTERNOON AND THE OUTER COASTAL ZONES THROUGH TONIGHT.
SMALL CRAFT ADVISORY CONDITIONS OVER THE CENTRAL STRAIT AND AT THE
EAST ENTRANCES WILL EASE THIS AFTERNOON AS PRES GRADIENTS RELAX.

WEAKER PRESSURE GRADIENTS WILL GIVE LIGHTER FLOW ON WEDNESDAY. SMALL
CRAFT ADVISORIES MAY NEED TO BE CONTINUED OVER THE OUTER COASTAL
ZONES WITH SEAS CONTINUING TO BE AROUND 10 FEET.

A COLD FRONT WILL APPROACH THE WATERS LATE THURSDAY AND THURSDAY
NIGHT. GALE FORCE WINDS ARE POSSIBLE WITH THIS FRONT...MAINLY OVER
THE COASTAL WATERS. A STRONGER SYSTEM ON SATURDAY COULD PRODUCES
GALES OVER THE NORTHERN INLAND WATERS AND STRAIT ENTRANCES IN
ADDITION TO THE COASTAL WATERS.

A LONG FETCH OF STRONG WESTERLY FLOW IS EXPECTED TO DEVELOP OVER THE
NORTH CENTRAL PACIFIC ON THURSDAY. THE WAVE WATCH MODEL...WITH WIND
FED BY THE GFS...IS SHOWING 30 FT SWELL PUSHING INTO THE OFFSHORE
WATERS FRI MORNING THEN ONSHORE SOMETIME FRIDAY AFTERNOON WITH A
HEIGHT OF 20-22 FT AND A PERIOD OF NEARLY 20 SECONDS. HIGH SURF
ADVISORIES WILL LIKELY BE NEEDED AT SOME POINT ALONG THE WASHINGTON
COAST FOR THIS EVENT. ALBRECHT

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY COAST...CENTRAL AND EAST STRAIT OF JUAN
     DE FUCA.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.

&&

$$

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML








000
FXUS66 KSEW 161719
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 AM PST TUE DEC 16 2014

.SYNOPSIS...WEAKENING WEATHER SYSTEMS TODAY AND WEDNESDAY ARE
EXPECTED TO PRODUCE SPOTTY LIGHT RAIN IN WESTERN WASHINGTON. A
STRONGER PACIFIC FRONTAL SYSTEM IS FORECAST TO ARRIVE LATER THURSDAY
INTO FRIDAY FOR MORE RAIN WITH ANOTHER SYSTEM FOLLOWING OVER THE
WEEKEND.
&&

.SHORT TERM...WV SATELLITE IMAGERY SHOWS A VERY DISTINCT SPLIT IN
THE UPPER AIR PATTERN ALONG THE W COAST. A LOW IS FORMING ON THE SRN
EXTENT OF AN APPROACHING FRONT WITH THE BULK OF ENERGY AND MOISTURE
DRIVING TOWARD CA. THE WEAKER NRN BRANCH OF THE JET WILL BRING
WEAKER LIFT AND MOISTURE ABOVE 925 MB. LOW LEVEL GRADIENTS WILL
INHIBIT SATURATION NEAR THE SURFACE SO PRECIPITATION AMOUNTS TODAY
WILL BE LIGHT AND SPOTTY. CURRENT RADAR LOOP IS SHOWING SOME LIGHT
RAIN JUST NOW PUSHING INTO PUGET SOUND. AS THIS BATCH OF LIGHT RAIN
MOVES THROUGH BY AFTERNOON...DRIER WEATHER WILL DEVELOP. BY
TONIGHT...ANY LIGHT LIGHT RAIN SHOULD BE CONFINED TO THE COAST AND
MOUNTAINS.

A TRAILING NRN STREAM SYSTEM WILL MOVE THROUGH THE AREA ON
WEDNESDAY. THIS WILL BE A SIMILAR TYPE SYSTEM WITH LOW QPF AMOUNTS
SHOWN BY MODELS. LIKELY POPS COAST AND MOUNTAINS WITH CHANCE POPS
OVER MOST THE INTERIOR LOWLANDS APPEARS REASONABLE. IT WILL REMAIN
COOL AND CLOUDY WITH HIGHS IN THE MID/UPPER 40S.

UPPER LEVEL HIGH PRESSURE WILL TRAVERSE THE AREA THURSDAY ACCORDING
TO THE GFS AND ECMWF. THE CANADIAN MODEL IS MUCH FASTER WITH THE
NEXT WETTER SYSTEM AND SPREADS RAIN INTO WRN WA BY 18Z THURSDAY. THE
ECMWF SHOWS RAIN BY LATE IN THE DAY AND THE GFS HOLDING OFF UNTIL
THURSDAY NIGHT. WILL LEAVE CHANCE POPS IN PLACE GIVEN THE MODELS
DISCREPANCY. WILL LOOK AT THE NEW 12Z RUNS BEFORE ANY MAKING ANY
ADJUSTMENTS WITH THE AFTERNOON FORECAST PACKAGE.  MERCER

.LONG TERM...NO UPDATE FROM PREVIOUS DISCUSSION...THE FRONTAL SYSTEM
MOVES ONSHORE BY FRIDAY MORNING WITH RAIN TURNING TO SHOWERS. BY
THIS TIME...THE JET HAS RETURNED TO OUR LATITUDE VS CALIFORNIA. A
SHORTWAVE RIDGE AHEAD OF THE NEXT TROUGH BUILDS ONSHORE SATURDAY
BEFORE THE NEXT PACIFIC FRONTAL SYSTEM ARRIVES BY SUNDAY.
AGAIN...PROG TIMING DIFFERS HERE. BUT THE DRIER DAY OVER THE WEEKEND
APPEARS TO BE SATURDAY.

PREVIOUS GUIDANCE OFFERED A PRETTY WET PERIOD SUNDAY INTO MONDAY.
CURRENT GUIDANCE HAS BACKED OFF TO SOME DEGREE. THIS SITUATION BEARS
WATCHING FOR NOW. ALSO KEEPING AN EYE ON A POSSIBLE KONA LOW THAT
WOULD CHANGE THE AMPLITUDE OF THE NORTHERN HEMISPHERE FLOW PATTERN
AND OFFER COOLER AIR FOR THE PACIFIC NW AND PERHAPS SOME SNOW FOR
THE SNOW STARVED MOUNTAINS IN THE LONGER RANGE. STAY TUNED HERE.
BUEHNER

&&

.HYDROLOGY...RIVER FLOODING IS NOT EXPECTED THROUGH AT LEAST
SATURDAY. A WETTER AND WARMER PATTERN WILL PROBABLY DEVELOP SUNDAY
AND MONDAY...AND SOME GUIDANCE SUGGESTING ENOUGH RAIN FOR A THREAT
OF FLOODING ON SOME OF THE MOST FLOOD-PRONE RIVERS. THE LATEST
GUIDANCE IS NOT QUITE AS WET AS PREVIOUS THOUGH. BUEHNER/MERCER

&&

.AVIATION...AN UPPER LEVEL TROUGH OVER THE OFFSHORE WATERS COMBINED
WITH HIGH PRES WELL EAST OF THE AREA IS GIVING LIGHT S FLOW ALOFT.
AT THE SURFACE...HIGH PRES E OF THE CASCADES COMBINED WITH A TROUGH
OF LOW PRES OFFSHORE IS GIVING LOW LEVEL OFFSHORE FLOW. THE AIR MASS
IS MOIST AND STABLE...EXCEPT IS DRY AT LOW LEVELS OVER THE INTERIOR
VALLEYS.

DESPITE ABUNDANT CLOUD COVER AND LIGHT PRECIPITATION...LOW LEVEL
OFFSHORE FLOW IS GIVING VFR CONDITIONS TO THE INTERIOR OF WESTERN
WASHINGTON THIS MORNING WITH GOOD VISIBILITY AND CIGS AROUND FLIGHT
LEVEL 040. MARGINAL VFR CEILINGS AND VISIBILITIES ARE OCCURRING
ALONG THE COAST WHERE PRECIPITATION RATES ARE HEAVIER AND CLOUD
BASES ARE FL 025-030. THE 12 KM NAM SOLUTION SHOWS LITTLE CHANGE IN
THE OVERALL PATTERN THROUGH ABOUT 07Z THIS EVENING FOLLOWED BY SOME
IMPROVEMENT TONIGHT AND WEDNESDAY MORNING BETWEEN THE INCOMING SPLIT
TROUGH AND THE NEXT ONE THAT ARRIVES WED NIGHT. THE 4 KM HRRR SHOWS
THE IMPROVEMENT TAKING PLACE FASTER...THIS AFTERNOON IN THE INTERIOR
SPREADING TO THE COAST OVERNIGHT. THE COASTAL RADAR SUGGESTS THAT
THE TYPICALLY SUPERIOR HRRR MAY BE A BIT FAST WITH ITS TIMING. THE
18Z TERMINALS WILL SPLIT THE DIFFERENCE. ALBRECHT

KSEA...VFR CONDITIONS WILL CONTINUE WITH BKN-OVC040 OVC060 AND
PERIODS OF VERY LIGHT RAIN AND VISIBILITIES 6KM OR HIGHER. EAST TO
SOUTHEAST WIND 5-9 KT. ALBRECHT

&&

.MARINE...HIGH PRES E OF THE CASCADES COMBINED WITH A TROUGH OF LOW
PRES OVER THE OFFSHORE WATERS IS GIVING OFFSHORE FLOW TO THE AREA
THIS MORNING. THIS OFFSHORE FLOW WILL GRADUALLY EASE LATER THIS
AFTERNOON AS THE OFFSHORE TROUGH MOVES ONSHORE AND WEAKENS. SMALL
CRAFT ADVISORY CONDITIONS WILL CONTINUE OVER THE COASTAL ZONES
THROUGH THIS AFTERNOON AND THE OUTER COASTAL ZONES THROUGH TONIGHT.
SMALL CRAFT ADVISORY CONDITIONS OVER THE CENTRAL STRAIT AND AT THE
EAST ENTRANCES WILL EASE THIS AFTERNOON AS PRES GRADIENTS RELAX.

WEAKER PRESSURE GRADIENTS WILL GIVE LIGHTER FLOW ON WEDNESDAY. SMALL
CRAFT ADVISORIES MAY NEED TO BE CONTINUED OVER THE OUTER COASTAL
ZONES WITH SEAS CONTINUING TO BE AROUND 10 FEET.

A COLD FRONT WILL APPROACH THE WATERS LATE THURSDAY AND THURSDAY
NIGHT. GALE FORCE WINDS ARE POSSIBLE WITH THIS FRONT...MAINLY OVER
THE COASTAL WATERS. A STRONGER SYSTEM ON SATURDAY COULD PRODUCES
GALES OVER THE NORTHERN INLAND WATERS AND STRAIT ENTRANCES IN
ADDITION TO THE COASTAL WATERS.

A LONG FETCH OF STRONG WESTERLY FLOW IS EXPECTED TO DEVELOP OVER THE
NORTH CENTRAL PACIFIC ON THURSDAY. THE WAVE WATCH MODEL...WITH WIND
FED BY THE GFS...IS SHOWING 30 FT SWELL PUSHING INTO THE OFFSHORE
WATERS FRI MORNING THEN ONSHORE SOMETIME FRIDAY AFTERNOON WITH A
HEIGHT OF 20-22 FT AND A PERIOD OF NEARLY 20 SECONDS. HIGH SURF
ADVISORIES WILL LIKELY BE NEEDED AT SOME POINT ALONG THE WASHINGTON
COAST FOR THIS EVENT. ALBRECHT

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY COAST...CENTRAL AND EAST STRAIT OF JUAN
     DE FUCA.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.

&&

$$

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML









000
FXUS66 KOTX 161614
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
814 AM PST TUE DEC 16 2014

.SYNOPSIS...
A weak storm system will bring light accumulations of snow
today to the areas near the Cascades and light rain or snow to the
western Columbia Basin. A more active weather pattern will
develop late in the week with generally mountain snow and valley
rain or minimally accumulating snow.

&&

.DISCUSSION...

Updates to this mornings forecast to add mention of very light
freezing rain to the Spokane area and vicinity as the upper air
sounding hints that there is likely to be a crossover temperature
at the top of the inversion at roughly 880mb to near +3 Celsius
atop the colder freezing layer below it this morning. That along
with most ground temperatures running below freezing made it a
reasonable addition. Little to no accumulation of snow or freezing
rain is included with the addition and generally valid wording for
most locations east of a Ritzville to Republic line. Those to the
west are either to remain snow or have warmed up enough already to
just call it rain, but there could be a few small pockets or two
this morning of a wintry mix there as well but pops are larger
with expectation that up-slope process gives those locations a
greater likelihood of receiving measurable precipitation. /Pelatti

&&

.AVIATION...
12Z TAFS: A weak upper level weather system will move north along
the Cascades this morning. This will increase clouds and result
in -RASN mainly west of a line from about Kettle Falls to the
Tri- Cities. So the best chances for precipitation will be at
KEAT/KMWH. Enough moisture may make it far enough east to keep
some light showers for the eastern TAF sites...but the confidence
of measuring is rather low. Precipitation type is expected to
start out as a -RA/SN mix before becoming mostly -RA. Surface obs
indicate some potential for light -FZRA for the upper basin...near
the Columbia river through 15-16z, but accumulations will be
light. Expect cigs to be VFR/MVFR at KEAT/KMWH through the day
then deteriorate aft 06z as fog/stratus try to develop. Conditions
for the eastern TAF sites should remain VFR with the potential for
MVFR cigs with any heavier precipitation. Guidance shows some
stratus development for KGEG/KSFF through the night...However this
may be overdone as a light easterly gradient would typically push
any moisture in the basin up against the Cascades. /Tobin

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        36  29  38  32  37  31 /  10  10  10  30  30  10
Coeur d`Alene  37  30  40  33  38  31 /  10  10  10  40  40  10
Pullman        40  29  42  32  41  32 /  10  10  10  30  30  10
Lewiston       43  32  42  35  43  34 /  20  10  10  30  30  10
Colville       34  28  36  31  37  31 /  40  30  20  30  30  20
Sandpoint      35  28  36  30  36  31 /  10  20  10  40  40  20
Kellogg        37  30  38  31  36  30 /  10  20  10  40  40  20
Moses Lake     37  28  38  28  38  30 /  60  10  20  20  10  30
Wenatchee      36  31  37  30  36  31 /  70  10  30  30  10  30
Omak           34  26  34  27  33  28 /  60  30  40  30  10  30

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$




000
FXUS66 KOTX 161614
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
814 AM PST TUE DEC 16 2014

.SYNOPSIS...
A weak storm system will bring light accumulations of snow
today to the areas near the Cascades and light rain or snow to the
western Columbia Basin. A more active weather pattern will
develop late in the week with generally mountain snow and valley
rain or minimally accumulating snow.

&&

.DISCUSSION...

Updates to this mornings forecast to add mention of very light
freezing rain to the Spokane area and vicinity as the upper air
sounding hints that there is likely to be a crossover temperature
at the top of the inversion at roughly 880mb to near +3 Celsius
atop the colder freezing layer below it this morning. That along
with most ground temperatures running below freezing made it a
reasonable addition. Little to no accumulation of snow or freezing
rain is included with the addition and generally valid wording for
most locations east of a Ritzville to Republic line. Those to the
west are either to remain snow or have warmed up enough already to
just call it rain, but there could be a few small pockets or two
this morning of a wintry mix there as well but pops are larger
with expectation that up-slope process gives those locations a
greater likelihood of receiving measurable precipitation. /Pelatti

&&

.AVIATION...
12Z TAFS: A weak upper level weather system will move north along
the Cascades this morning. This will increase clouds and result
in -RASN mainly west of a line from about Kettle Falls to the
Tri- Cities. So the best chances for precipitation will be at
KEAT/KMWH. Enough moisture may make it far enough east to keep
some light showers for the eastern TAF sites...but the confidence
of measuring is rather low. Precipitation type is expected to
start out as a -RA/SN mix before becoming mostly -RA. Surface obs
indicate some potential for light -FZRA for the upper basin...near
the Columbia river through 15-16z, but accumulations will be
light. Expect cigs to be VFR/MVFR at KEAT/KMWH through the day
then deteriorate aft 06z as fog/stratus try to develop. Conditions
for the eastern TAF sites should remain VFR with the potential for
MVFR cigs with any heavier precipitation. Guidance shows some
stratus development for KGEG/KSFF through the night...However this
may be overdone as a light easterly gradient would typically push
any moisture in the basin up against the Cascades. /Tobin

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        36  29  38  32  37  31 /  10  10  10  30  30  10
Coeur d`Alene  37  30  40  33  38  31 /  10  10  10  40  40  10
Pullman        40  29  42  32  41  32 /  10  10  10  30  30  10
Lewiston       43  32  42  35  43  34 /  20  10  10  30  30  10
Colville       34  28  36  31  37  31 /  40  30  20  30  30  20
Sandpoint      35  28  36  30  36  31 /  10  20  10  40  40  20
Kellogg        37  30  38  31  36  30 /  10  20  10  40  40  20
Moses Lake     37  28  38  28  38  30 /  60  10  20  20  10  30
Wenatchee      36  31  37  30  36  31 /  70  10  30  30  10  30
Omak           34  26  34  27  33  28 /  60  30  40  30  10  30

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$




000
FXUS66 KOTX 161614
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
814 AM PST TUE DEC 16 2014

.SYNOPSIS...
A weak storm system will bring light accumulations of snow
today to the areas near the Cascades and light rain or snow to the
western Columbia Basin. A more active weather pattern will
develop late in the week with generally mountain snow and valley
rain or minimally accumulating snow.

&&

.DISCUSSION...

Updates to this mornings forecast to add mention of very light
freezing rain to the Spokane area and vicinity as the upper air
sounding hints that there is likely to be a crossover temperature
at the top of the inversion at roughly 880mb to near +3 Celsius
atop the colder freezing layer below it this morning. That along
with most ground temperatures running below freezing made it a
reasonable addition. Little to no accumulation of snow or freezing
rain is included with the addition and generally valid wording for
most locations east of a Ritzville to Republic line. Those to the
west are either to remain snow or have warmed up enough already to
just call it rain, but there could be a few small pockets or two
this morning of a wintry mix there as well but pops are larger
with expectation that up-slope process gives those locations a
greater likelihood of receiving measurable precipitation. /Pelatti

&&

.AVIATION...
12Z TAFS: A weak upper level weather system will move north along
the Cascades this morning. This will increase clouds and result
in -RASN mainly west of a line from about Kettle Falls to the
Tri- Cities. So the best chances for precipitation will be at
KEAT/KMWH. Enough moisture may make it far enough east to keep
some light showers for the eastern TAF sites...but the confidence
of measuring is rather low. Precipitation type is expected to
start out as a -RA/SN mix before becoming mostly -RA. Surface obs
indicate some potential for light -FZRA for the upper basin...near
the Columbia river through 15-16z, but accumulations will be
light. Expect cigs to be VFR/MVFR at KEAT/KMWH through the day
then deteriorate aft 06z as fog/stratus try to develop. Conditions
for the eastern TAF sites should remain VFR with the potential for
MVFR cigs with any heavier precipitation. Guidance shows some
stratus development for KGEG/KSFF through the night...However this
may be overdone as a light easterly gradient would typically push
any moisture in the basin up against the Cascades. /Tobin

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        36  29  38  32  37  31 /  10  10  10  30  30  10
Coeur d`Alene  37  30  40  33  38  31 /  10  10  10  40  40  10
Pullman        40  29  42  32  41  32 /  10  10  10  30  30  10
Lewiston       43  32  42  35  43  34 /  20  10  10  30  30  10
Colville       34  28  36  31  37  31 /  40  30  20  30  30  20
Sandpoint      35  28  36  30  36  31 /  10  20  10  40  40  20
Kellogg        37  30  38  31  36  30 /  10  20  10  40  40  20
Moses Lake     37  28  38  28  38  30 /  60  10  20  20  10  30
Wenatchee      36  31  37  30  36  31 /  70  10  30  30  10  30
Omak           34  26  34  27  33  28 /  60  30  40  30  10  30

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$




000
FXUS66 KOTX 161614
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
814 AM PST TUE DEC 16 2014

.SYNOPSIS...
A weak storm system will bring light accumulations of snow
today to the areas near the Cascades and light rain or snow to the
western Columbia Basin. A more active weather pattern will
develop late in the week with generally mountain snow and valley
rain or minimally accumulating snow.

&&

.DISCUSSION...

Updates to this mornings forecast to add mention of very light
freezing rain to the Spokane area and vicinity as the upper air
sounding hints that there is likely to be a crossover temperature
at the top of the inversion at roughly 880mb to near +3 Celsius
atop the colder freezing layer below it this morning. That along
with most ground temperatures running below freezing made it a
reasonable addition. Little to no accumulation of snow or freezing
rain is included with the addition and generally valid wording for
most locations east of a Ritzville to Republic line. Those to the
west are either to remain snow or have warmed up enough already to
just call it rain, but there could be a few small pockets or two
this morning of a wintry mix there as well but pops are larger
with expectation that up-slope process gives those locations a
greater likelihood of receiving measurable precipitation. /Pelatti

&&

.AVIATION...
12Z TAFS: A weak upper level weather system will move north along
the Cascades this morning. This will increase clouds and result
in -RASN mainly west of a line from about Kettle Falls to the
Tri- Cities. So the best chances for precipitation will be at
KEAT/KMWH. Enough moisture may make it far enough east to keep
some light showers for the eastern TAF sites...but the confidence
of measuring is rather low. Precipitation type is expected to
start out as a -RA/SN mix before becoming mostly -RA. Surface obs
indicate some potential for light -FZRA for the upper basin...near
the Columbia river through 15-16z, but accumulations will be
light. Expect cigs to be VFR/MVFR at KEAT/KMWH through the day
then deteriorate aft 06z as fog/stratus try to develop. Conditions
for the eastern TAF sites should remain VFR with the potential for
MVFR cigs with any heavier precipitation. Guidance shows some
stratus development for KGEG/KSFF through the night...However this
may be overdone as a light easterly gradient would typically push
any moisture in the basin up against the Cascades. /Tobin

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        36  29  38  32  37  31 /  10  10  10  30  30  10
Coeur d`Alene  37  30  40  33  38  31 /  10  10  10  40  40  10
Pullman        40  29  42  32  41  32 /  10  10  10  30  30  10
Lewiston       43  32  42  35  43  34 /  20  10  10  30  30  10
Colville       34  28  36  31  37  31 /  40  30  20  30  30  20
Sandpoint      35  28  36  30  36  31 /  10  20  10  40  40  20
Kellogg        37  30  38  31  36  30 /  10  20  10  40  40  20
Moses Lake     37  28  38  28  38  30 /  60  10  20  20  10  30
Wenatchee      36  31  37  30  36  31 /  70  10  30  30  10  30
Omak           34  26  34  27  33  28 /  60  30  40  30  10  30

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$




000
FXUS66 KOTX 161203
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
403 AM PST TUE DEC 16 2014

.SYNOPSIS...
A weak storm system will bring light accumulations of snow
today to the areas near the Cascades and light rain or snow to the
western Columbia Basin. A more active weather pattern will
develop late in the week with generally mountain snow and valley
rain or minimally accumulating snow.


&&

.DISCUSSION...
Today through Wednesday...Through this portion of the forecast
period several weak frontal systems will try, but have
difficulty, moving through a strong ridge of high pressure in a
split flow pattern. The first weak wave is expected to move along
the east slopes of the Cascades this morning, then weaken further
as it tracks east across mainly the northern zones. As mentioned
this wave is fairly weak, but does have some moisture with it as
PWAT`s increasing to 150-170% of normal. While precipitation is
expected along the east slopes and the northern mountains any
amounts should be rather light, and on the order of a trace in the
Basin to around a tenth of an inch in the mountains.

With sunny skies temperatures were able to warm nicely Monday
afternoon and the temperatures were not able to radiate very
efficiently as the clouds began to move in soon after sunset. This
has kept temperatures across the lower elevation at or above
freezing so far. Some wet bulbing is expected across the lower
elevations of the Basin, Waterville Plateau, Wenatchee valley and
some of the mountain valleys for precipitation starting as light
snow before turning over to rain, with snow expected for the
mountains. It also looks like there may be some localized pockets
of freezing rain possible for the Waterville Plateau and the upper
Basin near the Columbia river. Some of the higher elevations in
the Cascades could see 1-2 inches of snow. Warm air advection will
be hampered by increased cloud cover and temperatures will be 2-4
degrees cooler today.

Some low end pops were kept in the forecast tonight and early
Wednesday for the northern mountains with up-sloping flow and
abundant low level moisture, but again accumulations should be
very light. Otherwise expect an increasing chance for fog and low
cloud development. By late Wednesday afternoon another very weak
front will begin to increase moisture for the Cascades. This wave
looks weaker than the one today and expect only light
accumulations and mainly near the crest. /Tobin

Wednesday night and Thursday...One weak system pushing through an
area of high pressure. This upper level trough with remnants of
Pacific moisture will dissipate as it moves east of the Cascades.
Under light winds and weak isentropic lift, the weak warm front
will lift north with warming with time. Expect light snow changing
to valley rain by Thursday with the main area across extreme
eastern Washington and north Idaho. The 850mb 0C line stays from
KMWH-LWS. It looks to be a slow mover with light precipitation
amounts. There looks to be a possible 1 inch in the northern
valleys while the northern mountains may experience 1-2 inches.
High pressure builds back in by late Thursday bringing a break in
the precipitation.

Thursday night through Friday night...Next system reaches the coast
as a warm front pushes east of Cascades late Thursday night. This
one looks to be a little stronger system and a little warmer.
Precipitation type will be tricky with a possible wintry mix. The
850mb 0C line spans from KEAT-KDEW by 12z Friday, and continues to
push north. This would bring mainly rain to the Columbia Basin and
lower valleys, while light snow is possible to the north. There
looks to be a possible 1-2 inches in the northern valleys, while
the northern mountains could see 1-3 inches. An occluded front
arrives Friday afternoon/eve and sweeps through the region with
light winds. Then drying occurs behind the front Friday night with
a brief break in the precipitation.

Saturday through Monday...This looks to be a wettest period. An
atmospheric river sets up and takes aim on the Pacific NW. Timing
of the onset is a little unclear for Saturday between the ECMWF
and GFS, with the GFS being the slower solution. But by 12z
Sunday, the models indicate a wet westerly flow spreading
plentiful moisture across the Inland NW which will continue into
early next week. There is a potential for moderate snow in the
east slopes of the northern Cascades and northern mountains at the
onset. Then the warming increases and looks to be a mainly
rain/high mountain snow event by Sunday afternoon. Winds will
increase by Sunday evening with speeds 20-30 kts across the
Columbia Basin. The 850mb 0C line pushes to the Canadian border
on Sunday while temps of +5C to +7C are found to the south. Sunday
appears to be the warmest day with widespread 40s and a few 50s
possible. Opted to raise POPs for this event and temperatures
especially for Saturday night and Sunday. There are some
indications that this hose of moisture will slide southward late
Monday, followed by a gradual cooling from the north. /rfox.


&&

.AVIATION...
12Z TAFS: A weak upper level weather system will move north along
the Cascades this morning. This will increase clouds and result
in -RASN mainly west of a line from about Kettle Falls to the
Tri- Cities. So the best chances for precipitation will be at
KEAT/KMWH. Enough moisture may make it far enough east to keep
some light showers for the eastern TAF sites...but the confidence
of measuring is rather low. Precipitation type is expected to
start out as a -RA/SN mix before becoming mostly -RA. Surface obs
indicate some potential for light -FZRA for the upper basin...near
the Columbia river through 15-16z, but accumulations will be
light. Expect cigs to be VFR/MVFR at KEAT/KMWH through the day
then deteriorate aft 06z as fog/stratus try to develop. Conditions
for the eastern TAF sites should remain VFR with the potential for
MVFR cigs with any heavier precipitation. Guidance shows some
stratus development for KGEG/KSFF through the night...However this
may be overdone as a light easterly gradient would typically push
any moisture in the basin up against the Cascades. /Tobin



&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        36  29  38  32  37  31 /  10  10  10  30  30  10
Coeur d`Alene  37  30  40  33  38  31 /  10  10  10  40  40  10
Pullman        40  29  42  32  41  32 /  10  10  10  30  30  10
Lewiston       43  32  42  35  43  34 /  20  10  10  30  30  10
Colville       34  28  36  31  37  31 /  40  30  20  30  30  20
Sandpoint      35  28  36  30  36  31 /  10  20  10  40  40  20
Kellogg        37  30  38  31  36  30 /  10  20  10  40  40  20
Moses Lake     37  28  38  28  38  30 /  60  10  20  20  10  30
Wenatchee      36  31  37  30  36  31 /  70  10  30  30  10  30
Omak           34  26  34  27  33  28 /  60  30  40  30  10  30

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 161203
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
403 AM PST TUE DEC 16 2014

.SYNOPSIS...
A weak storm system will bring light accumulations of snow
today to the areas near the Cascades and light rain or snow to the
western Columbia Basin. A more active weather pattern will
develop late in the week with generally mountain snow and valley
rain or minimally accumulating snow.


&&

.DISCUSSION...
Today through Wednesday...Through this portion of the forecast
period several weak frontal systems will try, but have
difficulty, moving through a strong ridge of high pressure in a
split flow pattern. The first weak wave is expected to move along
the east slopes of the Cascades this morning, then weaken further
as it tracks east across mainly the northern zones. As mentioned
this wave is fairly weak, but does have some moisture with it as
PWAT`s increasing to 150-170% of normal. While precipitation is
expected along the east slopes and the northern mountains any
amounts should be rather light, and on the order of a trace in the
Basin to around a tenth of an inch in the mountains.

With sunny skies temperatures were able to warm nicely Monday
afternoon and the temperatures were not able to radiate very
efficiently as the clouds began to move in soon after sunset. This
has kept temperatures across the lower elevation at or above
freezing so far. Some wet bulbing is expected across the lower
elevations of the Basin, Waterville Plateau, Wenatchee valley and
some of the mountain valleys for precipitation starting as light
snow before turning over to rain, with snow expected for the
mountains. It also looks like there may be some localized pockets
of freezing rain possible for the Waterville Plateau and the upper
Basin near the Columbia river. Some of the higher elevations in
the Cascades could see 1-2 inches of snow. Warm air advection will
be hampered by increased cloud cover and temperatures will be 2-4
degrees cooler today.

Some low end pops were kept in the forecast tonight and early
Wednesday for the northern mountains with up-sloping flow and
abundant low level moisture, but again accumulations should be
very light. Otherwise expect an increasing chance for fog and low
cloud development. By late Wednesday afternoon another very weak
front will begin to increase moisture for the Cascades. This wave
looks weaker than the one today and expect only light
accumulations and mainly near the crest. /Tobin

Wednesday night and Thursday...One weak system pushing through an
area of high pressure. This upper level trough with remnants of
Pacific moisture will dissipate as it moves east of the Cascades.
Under light winds and weak isentropic lift, the weak warm front
will lift north with warming with time. Expect light snow changing
to valley rain by Thursday with the main area across extreme
eastern Washington and north Idaho. The 850mb 0C line stays from
KMWH-LWS. It looks to be a slow mover with light precipitation
amounts. There looks to be a possible 1 inch in the northern
valleys while the northern mountains may experience 1-2 inches.
High pressure builds back in by late Thursday bringing a break in
the precipitation.

Thursday night through Friday night...Next system reaches the coast
as a warm front pushes east of Cascades late Thursday night. This
one looks to be a little stronger system and a little warmer.
Precipitation type will be tricky with a possible wintry mix. The
850mb 0C line spans from KEAT-KDEW by 12z Friday, and continues to
push north. This would bring mainly rain to the Columbia Basin and
lower valleys, while light snow is possible to the north. There
looks to be a possible 1-2 inches in the northern valleys, while
the northern mountains could see 1-3 inches. An occluded front
arrives Friday afternoon/eve and sweeps through the region with
light winds. Then drying occurs behind the front Friday night with
a brief break in the precipitation.

Saturday through Monday...This looks to be a wettest period. An
atmospheric river sets up and takes aim on the Pacific NW. Timing
of the onset is a little unclear for Saturday between the ECMWF
and GFS, with the GFS being the slower solution. But by 12z
Sunday, the models indicate a wet westerly flow spreading
plentiful moisture across the Inland NW which will continue into
early next week. There is a potential for moderate snow in the
east slopes of the northern Cascades and northern mountains at the
onset. Then the warming increases and looks to be a mainly
rain/high mountain snow event by Sunday afternoon. Winds will
increase by Sunday evening with speeds 20-30 kts across the
Columbia Basin. The 850mb 0C line pushes to the Canadian border
on Sunday while temps of +5C to +7C are found to the south. Sunday
appears to be the warmest day with widespread 40s and a few 50s
possible. Opted to raise POPs for this event and temperatures
especially for Saturday night and Sunday. There are some
indications that this hose of moisture will slide southward late
Monday, followed by a gradual cooling from the north. /rfox.


&&

.AVIATION...
12Z TAFS: A weak upper level weather system will move north along
the Cascades this morning. This will increase clouds and result
in -RASN mainly west of a line from about Kettle Falls to the
Tri- Cities. So the best chances for precipitation will be at
KEAT/KMWH. Enough moisture may make it far enough east to keep
some light showers for the eastern TAF sites...but the confidence
of measuring is rather low. Precipitation type is expected to
start out as a -RA/SN mix before becoming mostly -RA. Surface obs
indicate some potential for light -FZRA for the upper basin...near
the Columbia river through 15-16z, but accumulations will be
light. Expect cigs to be VFR/MVFR at KEAT/KMWH through the day
then deteriorate aft 06z as fog/stratus try to develop. Conditions
for the eastern TAF sites should remain VFR with the potential for
MVFR cigs with any heavier precipitation. Guidance shows some
stratus development for KGEG/KSFF through the night...However this
may be overdone as a light easterly gradient would typically push
any moisture in the basin up against the Cascades. /Tobin



&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        36  29  38  32  37  31 /  10  10  10  30  30  10
Coeur d`Alene  37  30  40  33  38  31 /  10  10  10  40  40  10
Pullman        40  29  42  32  41  32 /  10  10  10  30  30  10
Lewiston       43  32  42  35  43  34 /  20  10  10  30  30  10
Colville       34  28  36  31  37  31 /  40  30  20  30  30  20
Sandpoint      35  28  36  30  36  31 /  10  20  10  40  40  20
Kellogg        37  30  38  31  36  30 /  10  20  10  40  40  20
Moses Lake     37  28  38  28  38  30 /  60  10  20  20  10  30
Wenatchee      36  31  37  30  36  31 /  70  10  30  30  10  30
Omak           34  26  34  27  33  28 /  60  30  40  30  10  30

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$




000
FXUS66 KPQR 161131
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
330 AM PST TUE DEC 16 2014

.SYNOPSIS...A SERIES OF WEAK FRONTAL SYSTEMS CONTINUES TO MOVE
ONSHORE. HIGH PRESSURE REMAINS EAST OF THE CASCADES...PRODUCING
LOW-LEVEL OFFSHORE FLOW AND KEEPING THE AIR MASS DRY ENOUGH SO ONLY A
FEW LIGHT RAIN SHOWERS ARE ABLE TO REACH THE SURFACE. THIS PATTERN
WILL PREVAIL THROUGH MIDWEEK...THEN A STRONGER FRONT WILL BRING A
MORE SOLID SHOT OF RAIN TO THE AREA THURSDAY NIGHT. LOWERING SNOW
LEVELS SHOULD BRING SOME ACCUMULATING SNOW TO THE CASCADES FRIDAY AND
SATURDAY. HOWEVER...RISING SNOW LEVELS AND SUBTROPICAL MOISTURE
SPILLING INTO THE REGION WILL LIKELY BRING RAIN TO ALL BUT THE
HIGHEST PEAKS LATE IN THE WEEKEND AND EARLY NEXT WEEK.

&&

.SHORT TERM...TODAY THROUGH FRIDAY...LIGHT RAIN PERSISTS TODAY AS A
WEAK FRONTAL SYSTEM CONTINUES TO PUSH EAST OF THE FORECAST AREA EARLY
THIS MORNING. SURFACE OBSERVATIONS ARE REPORTING BETWEEN 0.01-0.05"
OF RAIN IN THE PAST 6 HOURS...EXCEPT FOR ALMOST 0.10" OF PRECIP OVER
THE COAST RANGE. THE NEXT FRONTAL SYSTEM CAN BE SEEN IN INFRARED
SATELLITE IMAGERY JUST OFF THE OREGON/CALIFORNIA COASTLINE THIS
MORNING. TEMPERATURES HAVE LOWERED TO 32-35 DEG F IN THE UPPER
PORTIONS OF THE HOOD RIVER VALLEY...WHERE SOME LIGHT SNOW
ACCUMULATIONS UP TO AN INCH OR SO ARE POSSIBLE THROUGH THIS MORNING.

EVEN WITH OFFSHORE FLOW PERSISTING...MODELS CONTINUE TO SHOW THE
EASTERLY GRADIENT STARTING TO SLACK OFF TODAY. GRADIENTS FURTHER
WEAKEN THROUGH LATE WED...AS HIGH PRESSURE SLOWLY WEAKENS EAST OF THE
CASCADES.

MODELS REMAIN CONSISTENT IN SHOWING MUCH OF THE ENERGY ASSOCIATED
WITH THIS NEXT LOW PRES SYSTEM HEADING SOUTH INTO NORTHERN CALIFORNIA
LATER TODAY. AS A REULT...OFFSHORE LOW LEVEL FLOW BECOMES REINFORCED
WHILE FLOW ALOFT TURNS A BIT MORE SOUTHERLY...ALLOWING SHOWER
ACTIVITY TO DIMINISH BY THIS AFTERNOON. SHOWERS MAY LINGER LONGER
ALONG THE CENTRAL OREGON COAST THOUGH. MOISTURE BEGINS TO SPREAD
ACROSS THE AREA AS THE CENTER OF THE LOW PRES DRIFTS TOWARDS THE
OREGON/CALIFORNIA BORDER OVERNIGHT TONIGHT INTO WEDNESDAY MORNING.
THE UPPER LEVEL TROUGH AXIS MOVES INLAND MIDDAY WEDNESDAY AND
WEDNESDAY NIGHT... WHICH SHOULD BRING ANOTHER ROUND OF PRECIP TO THE
AREA. BRIEF UPPER LEVEL RIDGING DEVELOPS FOR THURSDAY...BUT A WARM
FRONT AHEAD OF THE NEXT ORGANIZED FRONTAL BAND COULD BRING A THREAT
FOR PRECIP BY EARLY THURSDAY AFTERNOON. EAST WINDS MAY PICK UP AGAIN
THROUGH THE GORGE AS THIS SYSTEM APPROACHES THE COAST. THIS STRONG
FRONTAL SYSTEM PUSHES INTO THE PACIFIC NORTHWEST FRIDAY...BRINGING A
DECENT BATCH OF PRECIP TO THE AREA AS WELL AS GUSTY SOUTH WINDS FOR
THE COAST.

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...FRIDAY NIGHT
THROUGH MONDAY...A COLD AIR UNSTABLE AIRMASS WILL FOLLOW A STRONG
FRONTAL SYSTEM AND KEEP SHOWERS GOING INTO FRIDAY NIGHT. SNOW LEVELS
SHOULD LOWER TO NEAR 4000 FT ON SO ACCUMULATING SNOW APPEARS LIKELY
FOR AT LEAST THE HIGHER PASSES. AN ADDITIONAL SHORTWAVE TROUGH OR TWO
COULD ENHANCE SHOWER ACTIVITY EARLY IN THE WEEKEND AND BRING MUCH
NEEDED SNOW TO THE HIGHER CASCADES.

MODELS GENERALLY AGREE SNOW LEVELS WILL RISE LATE IN THE WEEKEND AS A
WARM FRONT SLIDES INTO THE REGION. STRONG ZONAL FLOW WILL FOCUS
PERSISTENT AND HEAVIER RAIN ACROSS SOUTHWEST BRITISH COLUMBIA AND
WESTERN WASHINGTON LATE IN THE WEEKEND AND EARLY NEXT WEEK. FOR
NOW...IT APPEARS THE BULK OF THE HEAVIEST RAIN WILL REMAIN NORTH OF
OUR REGION...AND WHEN HEAVIER PRECIPITATION ARRIVES...IT WILL REMAIN
TRANSIENT ENOUGH ACROSS OUR FORECAST AREA TO MINIMIZE FLOOD
CONCERNS. NONETHELESS...THIS PATTERN CERTAINLY BEARS
WATCHING...PARTICULARLY ACROSS THE NORTHERN HALF OF THE FORECAST
AREA WHERE A SLIGHT SHIFT IN THE STORM TRACK COULD PUT US IN THE
PATH OF A MODEST FIRE HOSE AND FLOOD CONCERNS WILL RISE. /NEUMAN


&&


.AVIATION...VFR CONDITIONS EXPECTED TO CONTINUE AT MOST TAF SITES
THROUGH WEDNESDAY MORNING. HOWEVER...AS A WEAK FRONT MOVES ACROSS
THE REGION WE COULD SEE BRIEF PERIODS OF MVFR TO IFR CIGS AND VIS
UNDER LIGHT TO MODERATE RAIN BANDS.

LOW LEVEL STRATUS HAS DEVELOPED OVER THE SOUTHERN WILLAMETTE
VALLEY THIS MORNING BRINGING LIFR TO IFR CIGS. EXPECT LIFR TO IFR
CIGS TO CONTINUE THROUGH AROUND 18Z. CONDITIONS SHOULD IMPROVE TO
VFR BY TUE AFTERNOON.

KPDX AND APPROACHES...VFR CONDITIONS WITH CIGS BETWEEN 4K TO 6K
FT THIS MORNING RISING TO AROUND 12K FT TUESDAY AFTERNOON. /64

&&

.MARINE...A WEAK FRONT WILL CONTINUE TO MOVE ACROSS THE WATERS
THIS MORNING. EXPECT SMALL CRAFT ADVISORY SEAS AND WINDS THROUGH
LATE TUESDAY MORNING. EXPECT SEAS TO STAY BELOW 10 FT THROUGH
EARLY WEDNESDAY MORNING. ANOTHER FRONTAL SYSTEM WILL MOVE ACROSS
THE WATERS ON WEDNESDAY AND COULD BRING ANOTHER ROUND OF SMALL
CRAFT ADVISORY WINDS AND SEAS. A MUCH STRONGER SYSTEM LOOKS TO
MOVE IN LATE THURSDAY INTO EARLY FRIDAY AND COULD BRING STRONG
GALE FORCE GUSTS AND 20 FT SEAS. /64

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.

WA...NONE.

PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL NOON PST TODAY FOR WATERS
     FROM CAPE SHOALWATER WA TO CASCADE HEAD OR FROM 10 TO 60 NM-
     WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 AM PST THIS
     MORNING FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE
     OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 4 AM
    PST WEDNESDAY.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.



000
FXUS66 KPQR 161131
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
330 AM PST TUE DEC 16 2014

.SYNOPSIS...A SERIES OF WEAK FRONTAL SYSTEMS CONTINUES TO MOVE
ONSHORE. HIGH PRESSURE REMAINS EAST OF THE CASCADES...PRODUCING
LOW-LEVEL OFFSHORE FLOW AND KEEPING THE AIR MASS DRY ENOUGH SO ONLY A
FEW LIGHT RAIN SHOWERS ARE ABLE TO REACH THE SURFACE. THIS PATTERN
WILL PREVAIL THROUGH MIDWEEK...THEN A STRONGER FRONT WILL BRING A
MORE SOLID SHOT OF RAIN TO THE AREA THURSDAY NIGHT. LOWERING SNOW
LEVELS SHOULD BRING SOME ACCUMULATING SNOW TO THE CASCADES FRIDAY AND
SATURDAY. HOWEVER...RISING SNOW LEVELS AND SUBTROPICAL MOISTURE
SPILLING INTO THE REGION WILL LIKELY BRING RAIN TO ALL BUT THE
HIGHEST PEAKS LATE IN THE WEEKEND AND EARLY NEXT WEEK.

&&

.SHORT TERM...TODAY THROUGH FRIDAY...LIGHT RAIN PERSISTS TODAY AS A
WEAK FRONTAL SYSTEM CONTINUES TO PUSH EAST OF THE FORECAST AREA EARLY
THIS MORNING. SURFACE OBSERVATIONS ARE REPORTING BETWEEN 0.01-0.05"
OF RAIN IN THE PAST 6 HOURS...EXCEPT FOR ALMOST 0.10" OF PRECIP OVER
THE COAST RANGE. THE NEXT FRONTAL SYSTEM CAN BE SEEN IN INFRARED
SATELLITE IMAGERY JUST OFF THE OREGON/CALIFORNIA COASTLINE THIS
MORNING. TEMPERATURES HAVE LOWERED TO 32-35 DEG F IN THE UPPER
PORTIONS OF THE HOOD RIVER VALLEY...WHERE SOME LIGHT SNOW
ACCUMULATIONS UP TO AN INCH OR SO ARE POSSIBLE THROUGH THIS MORNING.

EVEN WITH OFFSHORE FLOW PERSISTING...MODELS CONTINUE TO SHOW THE
EASTERLY GRADIENT STARTING TO SLACK OFF TODAY. GRADIENTS FURTHER
WEAKEN THROUGH LATE WED...AS HIGH PRESSURE SLOWLY WEAKENS EAST OF THE
CASCADES.

MODELS REMAIN CONSISTENT IN SHOWING MUCH OF THE ENERGY ASSOCIATED
WITH THIS NEXT LOW PRES SYSTEM HEADING SOUTH INTO NORTHERN CALIFORNIA
LATER TODAY. AS A REULT...OFFSHORE LOW LEVEL FLOW BECOMES REINFORCED
WHILE FLOW ALOFT TURNS A BIT MORE SOUTHERLY...ALLOWING SHOWER
ACTIVITY TO DIMINISH BY THIS AFTERNOON. SHOWERS MAY LINGER LONGER
ALONG THE CENTRAL OREGON COAST THOUGH. MOISTURE BEGINS TO SPREAD
ACROSS THE AREA AS THE CENTER OF THE LOW PRES DRIFTS TOWARDS THE
OREGON/CALIFORNIA BORDER OVERNIGHT TONIGHT INTO WEDNESDAY MORNING.
THE UPPER LEVEL TROUGH AXIS MOVES INLAND MIDDAY WEDNESDAY AND
WEDNESDAY NIGHT... WHICH SHOULD BRING ANOTHER ROUND OF PRECIP TO THE
AREA. BRIEF UPPER LEVEL RIDGING DEVELOPS FOR THURSDAY...BUT A WARM
FRONT AHEAD OF THE NEXT ORGANIZED FRONTAL BAND COULD BRING A THREAT
FOR PRECIP BY EARLY THURSDAY AFTERNOON. EAST WINDS MAY PICK UP AGAIN
THROUGH THE GORGE AS THIS SYSTEM APPROACHES THE COAST. THIS STRONG
FRONTAL SYSTEM PUSHES INTO THE PACIFIC NORTHWEST FRIDAY...BRINGING A
DECENT BATCH OF PRECIP TO THE AREA AS WELL AS GUSTY SOUTH WINDS FOR
THE COAST.

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...FRIDAY NIGHT
THROUGH MONDAY...A COLD AIR UNSTABLE AIRMASS WILL FOLLOW A STRONG
FRONTAL SYSTEM AND KEEP SHOWERS GOING INTO FRIDAY NIGHT. SNOW LEVELS
SHOULD LOWER TO NEAR 4000 FT ON SO ACCUMULATING SNOW APPEARS LIKELY
FOR AT LEAST THE HIGHER PASSES. AN ADDITIONAL SHORTWAVE TROUGH OR TWO
COULD ENHANCE SHOWER ACTIVITY EARLY IN THE WEEKEND AND BRING MUCH
NEEDED SNOW TO THE HIGHER CASCADES.

MODELS GENERALLY AGREE SNOW LEVELS WILL RISE LATE IN THE WEEKEND AS A
WARM FRONT SLIDES INTO THE REGION. STRONG ZONAL FLOW WILL FOCUS
PERSISTENT AND HEAVIER RAIN ACROSS SOUTHWEST BRITISH COLUMBIA AND
WESTERN WASHINGTON LATE IN THE WEEKEND AND EARLY NEXT WEEK. FOR
NOW...IT APPEARS THE BULK OF THE HEAVIEST RAIN WILL REMAIN NORTH OF
OUR REGION...AND WHEN HEAVIER PRECIPITATION ARRIVES...IT WILL REMAIN
TRANSIENT ENOUGH ACROSS OUR FORECAST AREA TO MINIMIZE FLOOD
CONCERNS. NONETHELESS...THIS PATTERN CERTAINLY BEARS
WATCHING...PARTICULARLY ACROSS THE NORTHERN HALF OF THE FORECAST
AREA WHERE A SLIGHT SHIFT IN THE STORM TRACK COULD PUT US IN THE
PATH OF A MODEST FIRE HOSE AND FLOOD CONCERNS WILL RISE. /NEUMAN


&&


.AVIATION...VFR CONDITIONS EXPECTED TO CONTINUE AT MOST TAF SITES
THROUGH WEDNESDAY MORNING. HOWEVER...AS A WEAK FRONT MOVES ACROSS
THE REGION WE COULD SEE BRIEF PERIODS OF MVFR TO IFR CIGS AND VIS
UNDER LIGHT TO MODERATE RAIN BANDS.

LOW LEVEL STRATUS HAS DEVELOPED OVER THE SOUTHERN WILLAMETTE
VALLEY THIS MORNING BRINGING LIFR TO IFR CIGS. EXPECT LIFR TO IFR
CIGS TO CONTINUE THROUGH AROUND 18Z. CONDITIONS SHOULD IMPROVE TO
VFR BY TUE AFTERNOON.

KPDX AND APPROACHES...VFR CONDITIONS WITH CIGS BETWEEN 4K TO 6K
FT THIS MORNING RISING TO AROUND 12K FT TUESDAY AFTERNOON. /64

&&

.MARINE...A WEAK FRONT WILL CONTINUE TO MOVE ACROSS THE WATERS
THIS MORNING. EXPECT SMALL CRAFT ADVISORY SEAS AND WINDS THROUGH
LATE TUESDAY MORNING. EXPECT SEAS TO STAY BELOW 10 FT THROUGH
EARLY WEDNESDAY MORNING. ANOTHER FRONTAL SYSTEM WILL MOVE ACROSS
THE WATERS ON WEDNESDAY AND COULD BRING ANOTHER ROUND OF SMALL
CRAFT ADVISORY WINDS AND SEAS. A MUCH STRONGER SYSTEM LOOKS TO
MOVE IN LATE THURSDAY INTO EARLY FRIDAY AND COULD BRING STRONG
GALE FORCE GUSTS AND 20 FT SEAS. /64

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.

WA...NONE.

PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL NOON PST TODAY FOR WATERS
     FROM CAPE SHOALWATER WA TO CASCADE HEAD OR FROM 10 TO 60 NM-
     WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 AM PST THIS
     MORNING FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE
     OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 4 AM
    PST WEDNESDAY.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.




000
FXUS66 KOTX 161118
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
317 AM PST TUE DEC 16 2014

.SYNOPSIS...
A weak storm system will bring light accumulations of snow
today to the areas near the Cascades and light rain or snow to the
western Columbia Basin. A more active weather pattern will
develop late in the week with generally mountain snow and valley
rain or minimally accumulating snow.


&&

.DISCUSSION...
Today through Wednesday...Through this portion of the forecast
period several weak frontal systems will try, but have
difficulty, moving through a strong ridge of high pressure in a
split flow pattern. The first weak wave is expected to move along
the east slopes of the Cascades this morning, then weaken further
as it tracks east across mainly the northern zones. As mentioned
this wave is fairly weak, but does have some moisture with it as
PWAT`s increasing to 150-170% of normal. While precipitation is
expected along the east slopes and the northern mountains any
amounts should be rather light, and on the order of a trace in the
Basin to around a tenth of an inch in the mountains.

With sunny skies temperatures were able to warm nicely Monday
afternoon and the temperatures were not able to radiate very
efficiently as the clouds began to move in soon after sunset. This
has kept temperatures across the lower elevation at or above
freezing so far. Some wet bulbing is expected across the lower
elevations of the Basin, Waterville Plateau, Wenatchee valley and
some of the mountain valleys for precipitation starting as light
snow before turning over to rain, with snow expected for the
mountains. It also looks like there may be some localized pockets
of freezing rain possible for the Waterville Plateau and the upper
Basin near the Columbia river. Some of the higher elevations in
the Cascades could see 1-2 inches of snow. Warm air advection will
be hampered by increased cloud cover and temperatures will be 2-4
degrees cooler today.

Some low end pops were kept in the forecast tonight and early
Wednesday for the northern mountains with up-sloping flow and
abundant low level moisture, but again accumulations should be
very light. Otherwise expect an increasing chance for fog and low
cloud development. By late Wednesday afternoon another very weak
front will begin to increase moisture for the Cascades. This wave
looks weaker than the one today and expect only light
accumulations and mainly near the crest. /Tobin

Wednesday night and Thursday...One weak system pushing through an
area of high pressure. This upper level trough with remnants of
Pacific moisture will dissipate as it moves east of the Cascades.
Under light winds and weak isentropic lift, the weak warm front
will lift north with warming with time. Expect light snow changing
to valley rain by Thursday with the main area across extreme
eastern Washington and north Idaho. The 850mb 0C line stays from
KMWH-LWS. It looks to be a slow mover with light precipitation
amounts. There looks to be a possible 1 inch in the northern
valleys while the northern mountains may experience 1-2 inches.
High pressure builds back in by late Thursday bringing a break in
the precipitation.

Thursday night through Friday night...Next system reaches the coast
as a warm front pushes east of Cascades late Thursday night. This
one looks to be a little stronger system and a little warmer.
Precipitation type will be tricky with a possible wintry mix. The
850mb 0C line spans from KEAT-KDEW by 12z Friday, and continues to
push north. This would bring mainly rain to the Columbia Basin and
lower valleys, while light snow is possible to the north. There
looks to be a possible 1-2 inches in the northern valleys, while
the northern mountains could see 1-3 inches. An occluded front
arrives Friday afternoon/eve and sweeps through the region with
light winds. Then drying occurs behind the front Friday night with
a brief break in the precipitation.

Saturday through Monday...This looks to be a wettest period. An
atmospheric river sets up and takes aim on the Pacific NW. Timing
of the onset is a little unclear for Saturday between the ECMWF
and GFS, with the GFS being the slower solution. But by 12z
Sunday, the models indicate a wet westerly flow spreading
plentiful moisture across the Inland NW which will continue into
early next week. There is a potential for moderate snow in the
east slopes of the northern Cascades and northern mountains at the
onset. Then the warming increases and looks to be a mainly
rain/high mountain snow event by Sunday afternoon. Winds will
increase by Sunday evening with speeds 20-30 kts across the
Columbia Basin. The 850mb 0C line pushes to the Canadian border
on Sunday while temps of +5C to +7C are found to the south. Sunday
appears to be the warmest day with widespread 40s and a few 50s
possible. Opted to raise POPs for this event and temperatures
especially for Saturday night and Sunday. There are some
indications that this hose of moisture will slide southward late
Monday, followed by a gradual cooling from the north. /rfox.


&&

.AVIATION...
06Z TAFS: A weak upper level disturbance will push into the region
overnight. Best chances for precip will be at KEAT and KMWH after
09Z. Precip type is expected to be predominately rain, but a
little bit of snow mixed in will be possible through the morning
hours. Expect cigs to deteriorate into MVFR category at these
locations as well. Lower levels of the atmosphere will have a
harder time moistening up at KGEG, KSFF, KCOE, KPUW and KLWS due
to a persistent drier easterly winds across these TAF locations.
Flurries will be possible at these locations with cigs expected to
lower down to between 2-5 kft agl depending on the elevation of
the TAF site. /SVH



&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        36  29  38  32  37  31 /  10  10  10  30  30  10
Coeur d`Alene  37  30  40  33  38  31 /  10  10  10  40  40  10
Pullman        40  29  42  32  41  32 /  10  10  10  30  30  10
Lewiston       43  32  42  35  43  34 /  20  10  10  30  30  10
Colville       34  28  36  31  37  31 /  40  30  20  30  30  20
Sandpoint      35  28  36  30  36  31 /  10  20  10  40  40  20
Kellogg        37  30  38  31  36  30 /  10  20  10  40  40  20
Moses Lake     37  28  38  28  38  30 /  60  10  20  20  10  30
Wenatchee      36  31  37  30  36  31 /  70  10  30  30  10  30
Omak           34  26  34  27  33  28 /  60  30  40  30  10  30

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 161118
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
317 AM PST TUE DEC 16 2014

.SYNOPSIS...
A weak storm system will bring light accumulations of snow
today to the areas near the Cascades and light rain or snow to the
western Columbia Basin. A more active weather pattern will
develop late in the week with generally mountain snow and valley
rain or minimally accumulating snow.


&&

.DISCUSSION...
Today through Wednesday...Through this portion of the forecast
period several weak frontal systems will try, but have
difficulty, moving through a strong ridge of high pressure in a
split flow pattern. The first weak wave is expected to move along
the east slopes of the Cascades this morning, then weaken further
as it tracks east across mainly the northern zones. As mentioned
this wave is fairly weak, but does have some moisture with it as
PWAT`s increasing to 150-170% of normal. While precipitation is
expected along the east slopes and the northern mountains any
amounts should be rather light, and on the order of a trace in the
Basin to around a tenth of an inch in the mountains.

With sunny skies temperatures were able to warm nicely Monday
afternoon and the temperatures were not able to radiate very
efficiently as the clouds began to move in soon after sunset. This
has kept temperatures across the lower elevation at or above
freezing so far. Some wet bulbing is expected across the lower
elevations of the Basin, Waterville Plateau, Wenatchee valley and
some of the mountain valleys for precipitation starting as light
snow before turning over to rain, with snow expected for the
mountains. It also looks like there may be some localized pockets
of freezing rain possible for the Waterville Plateau and the upper
Basin near the Columbia river. Some of the higher elevations in
the Cascades could see 1-2 inches of snow. Warm air advection will
be hampered by increased cloud cover and temperatures will be 2-4
degrees cooler today.

Some low end pops were kept in the forecast tonight and early
Wednesday for the northern mountains with up-sloping flow and
abundant low level moisture, but again accumulations should be
very light. Otherwise expect an increasing chance for fog and low
cloud development. By late Wednesday afternoon another very weak
front will begin to increase moisture for the Cascades. This wave
looks weaker than the one today and expect only light
accumulations and mainly near the crest. /Tobin

Wednesday night and Thursday...One weak system pushing through an
area of high pressure. This upper level trough with remnants of
Pacific moisture will dissipate as it moves east of the Cascades.
Under light winds and weak isentropic lift, the weak warm front
will lift north with warming with time. Expect light snow changing
to valley rain by Thursday with the main area across extreme
eastern Washington and north Idaho. The 850mb 0C line stays from
KMWH-LWS. It looks to be a slow mover with light precipitation
amounts. There looks to be a possible 1 inch in the northern
valleys while the northern mountains may experience 1-2 inches.
High pressure builds back in by late Thursday bringing a break in
the precipitation.

Thursday night through Friday night...Next system reaches the coast
as a warm front pushes east of Cascades late Thursday night. This
one looks to be a little stronger system and a little warmer.
Precipitation type will be tricky with a possible wintry mix. The
850mb 0C line spans from KEAT-KDEW by 12z Friday, and continues to
push north. This would bring mainly rain to the Columbia Basin and
lower valleys, while light snow is possible to the north. There
looks to be a possible 1-2 inches in the northern valleys, while
the northern mountains could see 1-3 inches. An occluded front
arrives Friday afternoon/eve and sweeps through the region with
light winds. Then drying occurs behind the front Friday night with
a brief break in the precipitation.

Saturday through Monday...This looks to be a wettest period. An
atmospheric river sets up and takes aim on the Pacific NW. Timing
of the onset is a little unclear for Saturday between the ECMWF
and GFS, with the GFS being the slower solution. But by 12z
Sunday, the models indicate a wet westerly flow spreading
plentiful moisture across the Inland NW which will continue into
early next week. There is a potential for moderate snow in the
east slopes of the northern Cascades and northern mountains at the
onset. Then the warming increases and looks to be a mainly
rain/high mountain snow event by Sunday afternoon. Winds will
increase by Sunday evening with speeds 20-30 kts across the
Columbia Basin. The 850mb 0C line pushes to the Canadian border
on Sunday while temps of +5C to +7C are found to the south. Sunday
appears to be the warmest day with widespread 40s and a few 50s
possible. Opted to raise POPs for this event and temperatures
especially for Saturday night and Sunday. There are some
indications that this hose of moisture will slide southward late
Monday, followed by a gradual cooling from the north. /rfox.


&&

.AVIATION...
06Z TAFS: A weak upper level disturbance will push into the region
overnight. Best chances for precip will be at KEAT and KMWH after
09Z. Precip type is expected to be predominately rain, but a
little bit of snow mixed in will be possible through the morning
hours. Expect cigs to deteriorate into MVFR category at these
locations as well. Lower levels of the atmosphere will have a
harder time moistening up at KGEG, KSFF, KCOE, KPUW and KLWS due
to a persistent drier easterly winds across these TAF locations.
Flurries will be possible at these locations with cigs expected to
lower down to between 2-5 kft agl depending on the elevation of
the TAF site. /SVH



&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        36  29  38  32  37  31 /  10  10  10  30  30  10
Coeur d`Alene  37  30  40  33  38  31 /  10  10  10  40  40  10
Pullman        40  29  42  32  41  32 /  10  10  10  30  30  10
Lewiston       43  32  42  35  43  34 /  20  10  10  30  30  10
Colville       34  28  36  31  37  31 /  40  30  20  30  30  20
Sandpoint      35  28  36  30  36  31 /  10  20  10  40  40  20
Kellogg        37  30  38  31  36  30 /  10  20  10  40  40  20
Moses Lake     37  28  38  28  38  30 /  60  10  20  20  10  30
Wenatchee      36  31  37  30  36  31 /  70  10  30  30  10  30
Omak           34  26  34  27  33  28 /  60  30  40  30  10  30

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 161118
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
317 AM PST TUE DEC 16 2014

.SYNOPSIS...
A weak storm system will bring light accumulations of snow
today to the areas near the Cascades and light rain or snow to the
western Columbia Basin. A more active weather pattern will
develop late in the week with generally mountain snow and valley
rain or minimally accumulating snow.


&&

.DISCUSSION...
Today through Wednesday...Through this portion of the forecast
period several weak frontal systems will try, but have
difficulty, moving through a strong ridge of high pressure in a
split flow pattern. The first weak wave is expected to move along
the east slopes of the Cascades this morning, then weaken further
as it tracks east across mainly the northern zones. As mentioned
this wave is fairly weak, but does have some moisture with it as
PWAT`s increasing to 150-170% of normal. While precipitation is
expected along the east slopes and the northern mountains any
amounts should be rather light, and on the order of a trace in the
Basin to around a tenth of an inch in the mountains.

With sunny skies temperatures were able to warm nicely Monday
afternoon and the temperatures were not able to radiate very
efficiently as the clouds began to move in soon after sunset. This
has kept temperatures across the lower elevation at or above
freezing so far. Some wet bulbing is expected across the lower
elevations of the Basin, Waterville Plateau, Wenatchee valley and
some of the mountain valleys for precipitation starting as light
snow before turning over to rain, with snow expected for the
mountains. It also looks like there may be some localized pockets
of freezing rain possible for the Waterville Plateau and the upper
Basin near the Columbia river. Some of the higher elevations in
the Cascades could see 1-2 inches of snow. Warm air advection will
be hampered by increased cloud cover and temperatures will be 2-4
degrees cooler today.

Some low end pops were kept in the forecast tonight and early
Wednesday for the northern mountains with up-sloping flow and
abundant low level moisture, but again accumulations should be
very light. Otherwise expect an increasing chance for fog and low
cloud development. By late Wednesday afternoon another very weak
front will begin to increase moisture for the Cascades. This wave
looks weaker than the one today and expect only light
accumulations and mainly near the crest. /Tobin

Wednesday night and Thursday...One weak system pushing through an
area of high pressure. This upper level trough with remnants of
Pacific moisture will dissipate as it moves east of the Cascades.
Under light winds and weak isentropic lift, the weak warm front
will lift north with warming with time. Expect light snow changing
to valley rain by Thursday with the main area across extreme
eastern Washington and north Idaho. The 850mb 0C line stays from
KMWH-LWS. It looks to be a slow mover with light precipitation
amounts. There looks to be a possible 1 inch in the northern
valleys while the northern mountains may experience 1-2 inches.
High pressure builds back in by late Thursday bringing a break in
the precipitation.

Thursday night through Friday night...Next system reaches the coast
as a warm front pushes east of Cascades late Thursday night. This
one looks to be a little stronger system and a little warmer.
Precipitation type will be tricky with a possible wintry mix. The
850mb 0C line spans from KEAT-KDEW by 12z Friday, and continues to
push north. This would bring mainly rain to the Columbia Basin and
lower valleys, while light snow is possible to the north. There
looks to be a possible 1-2 inches in the northern valleys, while
the northern mountains could see 1-3 inches. An occluded front
arrives Friday afternoon/eve and sweeps through the region with
light winds. Then drying occurs behind the front Friday night with
a brief break in the precipitation.

Saturday through Monday...This looks to be a wettest period. An
atmospheric river sets up and takes aim on the Pacific NW. Timing
of the onset is a little unclear for Saturday between the ECMWF
and GFS, with the GFS being the slower solution. But by 12z
Sunday, the models indicate a wet westerly flow spreading
plentiful moisture across the Inland NW which will continue into
early next week. There is a potential for moderate snow in the
east slopes of the northern Cascades and northern mountains at the
onset. Then the warming increases and looks to be a mainly
rain/high mountain snow event by Sunday afternoon. Winds will
increase by Sunday evening with speeds 20-30 kts across the
Columbia Basin. The 850mb 0C line pushes to the Canadian border
on Sunday while temps of +5C to +7C are found to the south. Sunday
appears to be the warmest day with widespread 40s and a few 50s
possible. Opted to raise POPs for this event and temperatures
especially for Saturday night and Sunday. There are some
indications that this hose of moisture will slide southward late
Monday, followed by a gradual cooling from the north. /rfox.


&&

.AVIATION...
06Z TAFS: A weak upper level disturbance will push into the region
overnight. Best chances for precip will be at KEAT and KMWH after
09Z. Precip type is expected to be predominately rain, but a
little bit of snow mixed in will be possible through the morning
hours. Expect cigs to deteriorate into MVFR category at these
locations as well. Lower levels of the atmosphere will have a
harder time moistening up at KGEG, KSFF, KCOE, KPUW and KLWS due
to a persistent drier easterly winds across these TAF locations.
Flurries will be possible at these locations with cigs expected to
lower down to between 2-5 kft agl depending on the elevation of
the TAF site. /SVH



&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        36  29  38  32  37  31 /  10  10  10  30  30  10
Coeur d`Alene  37  30  40  33  38  31 /  10  10  10  40  40  10
Pullman        40  29  42  32  41  32 /  10  10  10  30  30  10
Lewiston       43  32  42  35  43  34 /  20  10  10  30  30  10
Colville       34  28  36  31  37  31 /  40  30  20  30  30  20
Sandpoint      35  28  36  30  36  31 /  10  20  10  40  40  20
Kellogg        37  30  38  31  36  30 /  10  20  10  40  40  20
Moses Lake     37  28  38  28  38  30 /  60  10  20  20  10  30
Wenatchee      36  31  37  30  36  31 /  70  10  30  30  10  30
Omak           34  26  34  27  33  28 /  60  30  40  30  10  30

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 161118
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
317 AM PST TUE DEC 16 2014

.SYNOPSIS...
A weak storm system will bring light accumulations of snow
today to the areas near the Cascades and light rain or snow to the
western Columbia Basin. A more active weather pattern will
develop late in the week with generally mountain snow and valley
rain or minimally accumulating snow.


&&

.DISCUSSION...
Today through Wednesday...Through this portion of the forecast
period several weak frontal systems will try, but have
difficulty, moving through a strong ridge of high pressure in a
split flow pattern. The first weak wave is expected to move along
the east slopes of the Cascades this morning, then weaken further
as it tracks east across mainly the northern zones. As mentioned
this wave is fairly weak, but does have some moisture with it as
PWAT`s increasing to 150-170% of normal. While precipitation is
expected along the east slopes and the northern mountains any
amounts should be rather light, and on the order of a trace in the
Basin to around a tenth of an inch in the mountains.

With sunny skies temperatures were able to warm nicely Monday
afternoon and the temperatures were not able to radiate very
efficiently as the clouds began to move in soon after sunset. This
has kept temperatures across the lower elevation at or above
freezing so far. Some wet bulbing is expected across the lower
elevations of the Basin, Waterville Plateau, Wenatchee valley and
some of the mountain valleys for precipitation starting as light
snow before turning over to rain, with snow expected for the
mountains. It also looks like there may be some localized pockets
of freezing rain possible for the Waterville Plateau and the upper
Basin near the Columbia river. Some of the higher elevations in
the Cascades could see 1-2 inches of snow. Warm air advection will
be hampered by increased cloud cover and temperatures will be 2-4
degrees cooler today.

Some low end pops were kept in the forecast tonight and early
Wednesday for the northern mountains with up-sloping flow and
abundant low level moisture, but again accumulations should be
very light. Otherwise expect an increasing chance for fog and low
cloud development. By late Wednesday afternoon another very weak
front will begin to increase moisture for the Cascades. This wave
looks weaker than the one today and expect only light
accumulations and mainly near the crest. /Tobin

Wednesday night and Thursday...One weak system pushing through an
area of high pressure. This upper level trough with remnants of
Pacific moisture will dissipate as it moves east of the Cascades.
Under light winds and weak isentropic lift, the weak warm front
will lift north with warming with time. Expect light snow changing
to valley rain by Thursday with the main area across extreme
eastern Washington and north Idaho. The 850mb 0C line stays from
KMWH-LWS. It looks to be a slow mover with light precipitation
amounts. There looks to be a possible 1 inch in the northern
valleys while the northern mountains may experience 1-2 inches.
High pressure builds back in by late Thursday bringing a break in
the precipitation.

Thursday night through Friday night...Next system reaches the coast
as a warm front pushes east of Cascades late Thursday night. This
one looks to be a little stronger system and a little warmer.
Precipitation type will be tricky with a possible wintry mix. The
850mb 0C line spans from KEAT-KDEW by 12z Friday, and continues to
push north. This would bring mainly rain to the Columbia Basin and
lower valleys, while light snow is possible to the north. There
looks to be a possible 1-2 inches in the northern valleys, while
the northern mountains could see 1-3 inches. An occluded front
arrives Friday afternoon/eve and sweeps through the region with
light winds. Then drying occurs behind the front Friday night with
a brief break in the precipitation.

Saturday through Monday...This looks to be a wettest period. An
atmospheric river sets up and takes aim on the Pacific NW. Timing
of the onset is a little unclear for Saturday between the ECMWF
and GFS, with the GFS being the slower solution. But by 12z
Sunday, the models indicate a wet westerly flow spreading
plentiful moisture across the Inland NW which will continue into
early next week. There is a potential for moderate snow in the
east slopes of the northern Cascades and northern mountains at the
onset. Then the warming increases and looks to be a mainly
rain/high mountain snow event by Sunday afternoon. Winds will
increase by Sunday evening with speeds 20-30 kts across the
Columbia Basin. The 850mb 0C line pushes to the Canadian border
on Sunday while temps of +5C to +7C are found to the south. Sunday
appears to be the warmest day with widespread 40s and a few 50s
possible. Opted to raise POPs for this event and temperatures
especially for Saturday night and Sunday. There are some
indications that this hose of moisture will slide southward late
Monday, followed by a gradual cooling from the north. /rfox.


&&

.AVIATION...
06Z TAFS: A weak upper level disturbance will push into the region
overnight. Best chances for precip will be at KEAT and KMWH after
09Z. Precip type is expected to be predominately rain, but a
little bit of snow mixed in will be possible through the morning
hours. Expect cigs to deteriorate into MVFR category at these
locations as well. Lower levels of the atmosphere will have a
harder time moistening up at KGEG, KSFF, KCOE, KPUW and KLWS due
to a persistent drier easterly winds across these TAF locations.
Flurries will be possible at these locations with cigs expected to
lower down to between 2-5 kft agl depending on the elevation of
the TAF site. /SVH



&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        36  29  38  32  37  31 /  10  10  10  30  30  10
Coeur d`Alene  37  30  40  33  38  31 /  10  10  10  40  40  10
Pullman        40  29  42  32  41  32 /  10  10  10  30  30  10
Lewiston       43  32  42  35  43  34 /  20  10  10  30  30  10
Colville       34  28  36  31  37  31 /  40  30  20  30  30  20
Sandpoint      35  28  36  30  36  31 /  10  20  10  40  40  20
Kellogg        37  30  38  31  36  30 /  10  20  10  40  40  20
Moses Lake     37  28  38  28  38  30 /  60  10  20  20  10  30
Wenatchee      36  31  37  30  36  31 /  70  10  30  30  10  30
Omak           34  26  34  27  33  28 /  60  30  40  30  10  30

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 161115
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
312 AM PST TUE DEC 16 2014

.SYNOPSIS...
A weak storm system will bring light accumulations of snow
tonight and Tuesday to the areas near the Cascades. A more active
weather pattern will develop late in the week with generally
mountain snow and valley rain or minimally accumulating snow.



&&

.DISCUSSION...

Wednesday night and Thursday...One weak system pushing through an
area of high pressure. This upper level trough with remnants of
Pacific moisture will disipate as it moves east of the Cascades.
Under light winds and weak isentropic lift, the weak warm front
will lift north with warming with time. Expect light snow changing
to valley rain by Thursday with the main area across extreme
eastern Washington and north Idaho. The 850mb 0C line stays from
KMWH-LWS. It looks to be a slow mover with light precipitation
amounts. There looks to be a possible 1 inch in the northern
valleys while the northern mountains may experience 1-2 inches.
High pressure builds back in by late Thursday bringing a break in
the precipitation.

Thursday night through Friday night...Next system reaches the coast
as a warm front pushes east of Cascades late Thursday night. This
one looks to be a little stronger system and a little warmer.
Precipitation type will be tricky with a possible wintry mix. The
850mb 0C line spans from KEAT-KDEW by 12z Friday, and continues to
push north. This would bring mainly rain to the Columbia Basin and
lower valleys, while light snow is possible to the north. There
looks to be a possible 1-2 inches in the northern valleys, while
the northern mountains could see 1-3 inches. An occluded front
arrives Friday afternoon/eve and sweeps through the region with
light winds. Then drying occurs behind the front Friday night with
a brief break in the precipitation.

Saturday through Monday...This looks to be a wettest period. An
atmospheric river sets up and takes aim on the Pacific NW. Timing
of the onset is a little unclear for Saturday between the ECMWF
and GFS, with the GFS being the slower solution. But by 12z
Sunday, the models indicate a wet westerly flow spreading
plentiful moisture across the Inland NW which will continue into
early next week. There is a potential for moderate snow in the
east slopes of the northern Cascades and northern mountains at the
onset. Then the warming increases and looks to be a mainly
rain/high mountain snow event by Sunday afternoon. Winds will
increase by Sunday evening with speeds 20-30 kts across the
Columbia Basin. The 850mb 0C line pushes to the Canaidan border on
Sunday while temps of +5C to +7C are found to the south. Sunday
appears to be the warmest day with widespread 40s and a few 50s
possible. Opted to raise POPs for this event and temperatures
especially for Saturday night and Sunday. There are some
indications that this hose of moisture will slide southward late
Monday, followed by a gradual cooling from the north. /rfox.


&&

.AVIATION...
06Z TAFS: A weak upper level disturbance will push into the region
overnight. Best chances for precip will be at KEAT and KMWH after
09Z. Precip type is expected to be predominately rain, but a
little bit of snow mixed in will be possible through the morning
hours. Expect cigs to deteriorate into MVFR category at these
locations as well. Lower levels of the atmosphere will have a
harder time moistening up at KGEG, KSFF, KCOE, KPUW and KLWS due
to a persistent drier easterly winds across these TAF locations.
Flurries will be possible at these locations with cigs expected to
lower down to between 2-5 kft agl depending on the elevation of
the TAF site. /SVH



&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        36  29  38  32  37  31 /  10  10  10  30  30  10
Coeur d`Alene  37  30  40  33  38  31 /  10  10  10  40  40  10
Pullman        40  29  42  32  41  32 /  10  10  10  30  30  10
Lewiston       43  32  42  35  43  34 /  20  10  10  30  30  10
Colville       34  28  36  31  37  31 /  40  30  20  30  30  20
Sandpoint      35  28  36  30  36  31 /  10  20  10  40  40  20
Kellogg        37  30  38  31  36  30 /  10  20  10  40  40  20
Moses Lake     37  28  38  28  38  30 /  60  10  20  20  10  30
Wenatchee      36  31  37  30  36  31 /  70  10  30  30  10  30
Omak           34  26  34  27  33  28 /  60  30  40  30  10  30

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KOTX 161115
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
312 AM PST TUE DEC 16 2014

.SYNOPSIS...
A weak storm system will bring light accumulations of snow
tonight and Tuesday to the areas near the Cascades. A more active
weather pattern will develop late in the week with generally
mountain snow and valley rain or minimally accumulating snow.



&&

.DISCUSSION...

Wednesday night and Thursday...One weak system pushing through an
area of high pressure. This upper level trough with remnants of
Pacific moisture will disipate as it moves east of the Cascades.
Under light winds and weak isentropic lift, the weak warm front
will lift north with warming with time. Expect light snow changing
to valley rain by Thursday with the main area across extreme
eastern Washington and north Idaho. The 850mb 0C line stays from
KMWH-LWS. It looks to be a slow mover with light precipitation
amounts. There looks to be a possible 1 inch in the northern
valleys while the northern mountains may experience 1-2 inches.
High pressure builds back in by late Thursday bringing a break in
the precipitation.

Thursday night through Friday night...Next system reaches the coast
as a warm front pushes east of Cascades late Thursday night. This
one looks to be a little stronger system and a little warmer.
Precipitation type will be tricky with a possible wintry mix. The
850mb 0C line spans from KEAT-KDEW by 12z Friday, and continues to
push north. This would bring mainly rain to the Columbia Basin and
lower valleys, while light snow is possible to the north. There
looks to be a possible 1-2 inches in the northern valleys, while
the northern mountains could see 1-3 inches. An occluded front
arrives Friday afternoon/eve and sweeps through the region with
light winds. Then drying occurs behind the front Friday night with
a brief break in the precipitation.

Saturday through Monday...This looks to be a wettest period. An
atmospheric river sets up and takes aim on the Pacific NW. Timing
of the onset is a little unclear for Saturday between the ECMWF
and GFS, with the GFS being the slower solution. But by 12z
Sunday, the models indicate a wet westerly flow spreading
plentiful moisture across the Inland NW which will continue into
early next week. There is a potential for moderate snow in the
east slopes of the northern Cascades and northern mountains at the
onset. Then the warming increases and looks to be a mainly
rain/high mountain snow event by Sunday afternoon. Winds will
increase by Sunday evening with speeds 20-30 kts across the
Columbia Basin. The 850mb 0C line pushes to the Canaidan border on
Sunday while temps of +5C to +7C are found to the south. Sunday
appears to be the warmest day with widespread 40s and a few 50s
possible. Opted to raise POPs for this event and temperatures
especially for Saturday night and Sunday. There are some
indications that this hose of moisture will slide southward late
Monday, followed by a gradual cooling from the north. /rfox.


&&

.AVIATION...
06Z TAFS: A weak upper level disturbance will push into the region
overnight. Best chances for precip will be at KEAT and KMWH after
09Z. Precip type is expected to be predominately rain, but a
little bit of snow mixed in will be possible through the morning
hours. Expect cigs to deteriorate into MVFR category at these
locations as well. Lower levels of the atmosphere will have a
harder time moistening up at KGEG, KSFF, KCOE, KPUW and KLWS due
to a persistent drier easterly winds across these TAF locations.
Flurries will be possible at these locations with cigs expected to
lower down to between 2-5 kft agl depending on the elevation of
the TAF site. /SVH



&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        36  29  38  32  37  31 /  10  10  10  30  30  10
Coeur d`Alene  37  30  40  33  38  31 /  10  10  10  40  40  10
Pullman        40  29  42  32  41  32 /  10  10  10  30  30  10
Lewiston       43  32  42  35  43  34 /  20  10  10  30  30  10
Colville       34  28  36  31  37  31 /  40  30  20  30  30  20
Sandpoint      35  28  36  30  36  31 /  10  20  10  40  40  20
Kellogg        37  30  38  31  36  30 /  10  20  10  40  40  20
Moses Lake     37  28  38  28  38  30 /  60  10  20  20  10  30
Wenatchee      36  31  37  30  36  31 /  70  10  30  30  10  30
Omak           34  26  34  27  33  28 /  60  30  40  30  10  30

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$




000
FXUS66 KSEW 161046
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 AM PST TUE DEC 16 2014

.SYNOPSIS...WEAKENING WEATHER SYSTEMS TODAY AND WEDNESDAY ARE
EXPECTED TO PRODUCE SPOTTY LIGHT RAIN IN WESTERN WASHINGTON. A
STRONGER PACIFIC FRONTAL SYSTEM IS FORECAST TO ARRIVE LATER THURSDAY
INTO FRIDAY FOR MORE RAIN WITH ANOTHER SYSTEM FOLLOWING OVER THE
WEEKEND.
&&

.SHORT TERM...SATELLITE IMAGES SHOW A NEGATIVE TILTED UPPER TROUGH
OFFSHORE WITH A SPLIT FLOW PATTERN AND THE PRIMARY JET STREAM AIMED
AT CALIFORNIA. A PAIR OF WEAK SHORTWAVES ARE MOVING THROUGH THE
TROUGH AND SHOULD WEAKEN FURTHER AS THEY MOVE ONSHORE GIVEN THE LOW
LEVEL OFFSHORE FLOW. THE FIRST IS PRODUCING SPOTTY LIGHT RAIN IN
SOUTHERLY FLOW ALOFT PER DOPPLER WEATHER RADAR AND SHOULD CONTINUE
INTO TODAY. THE FOLLOWING SHORTWAVE APPROACHING 130W EARLY THIS
MORNING IS EXPECTED TO ARRIVE WEDNESDAY FOR A REPEAT OF SPOTTY RAIN
WITH LIGHT AMOUNTS. BEST POPS WILL BE ALONG THE COAST.

THE NEXT SHORTWAVE NOW NEAR 170W AND PER GUIDANCE...SHOULD BUILD AN
UPPER RIDGE AHEAD OF IT MOVING ONSHORE WEDNESDAY NIGHT INTO
THURSDAY. TIMING ON THE SHORTWAVES ASSOCIATED FRONTAL SYSTEM ARRIVAL
IS A BIT IN QUESTION WITH THE GFS SLOWER THURSDAY VICE THE FASTER
CANADIAN AND ECMWF. GIVEN THE CURRENT SPLIT FLOW...GOING SLOWER MAY
BE THE BETTER SOLUTION. SO THE FORECAST WILL SHOW AN INCREASING
THREAT OF RAIN THROUGHOUT THE DAY WITH THE COAST LIKELY IN THE
AFTERNOON. BUEHNER

.LONG TERM...THE FRONTAL SYSTEM MOVES ONSHORE BY FRIDAY MORNING WITH
RAIN TURNING TO SHOWERS. BY THIS TIME...THE JET HAS RETURNED TO OUR
LATITUDE VS CALIFORNIA. A SHORTWAVE RIDGE AHEAD OF THE NEXT TROUGH
BUILDS ONSHORE SATURDAY BEFORE THE NEXT PACIFIC FRONTAL SYSTEM
ARRIVES BY SUNDAY. AGAIN...PROG TIMING DIFFERS HERE. BUT THE DRIER
DAY OVER THE WEEKEND APPEARS TO BE SATURDAY.

PREVIOUS GUIDANCE OFFERED A PRETTY WET PERIOD SUNDAY INTO MONDAY.
CURRENT GUIDANCE HAS BACKED OFF TO SOME DEGREE. THIS SITUATION BEARS
WATCHING FOR NOW. ALSO KEEPING AN EYE ON A POSSIBLE KONA LOW THAT
WOULD CHANGE THE AMPLITUDE OF THE NORTHERN HEMISPHERE FLOW PATTERN
AND OFFER COOLER AIR FOR THE PACIFIC NW AND PERHAPS SOME SNOW FOR
THE SNOW STARVED MOUNTAINS IN THE LONGER RANGE. STAY TUNED HERE.
BUEHNER

&&

.HYDROLOGY...RIVER FLOODING IS NOT EXPECTED THROUGH AT LEAST
SATURDAY. A WETTER AND WARMER PATTERN WILL PROBABLY DEVELOP SUNDAY
AND MONDAY...AND SOME GUIDANCE SUGGESTING ENOUGH RAIN FOR A THREAT
OF FLOODING ON SOME OF THE MOST FLOOD-PRONE RIVERS. THE LATEST
GUIDANCE IS NOT QUITE AS WET AS PREVIOUS THOUGH. BUEHNER

&&

.AVIATION...AN UPPER LEVEL TROUGH OVER THE OFFSHORE WATERS WILL
PRODUCE SOUTH TO SOUTHWEST FLOW ALOFT OVER WESTERN WASHINGTON TODAY.
LOW LEVEL OFFSHORE FLOW CONTINUES WITH SURFACE HIGH PRESSURE
CENTERED OVER INTERIOR SOUTHERN BRITISH COLUMBIA AND A BROAD TROUGH
OFFSHORE. THE AIR MASS IS STABLE WITH MAINLY MID AND UPPER LEVEL
MOISTURE OVER WESTERN WASHINGTON. LOW LEVELS WILL GRADUALLY MOISTEN
TODAY AS EASTERLY LOW LEVEL FLOW WEAKENS AND AREAS OF VERY LIGHT
RAIN MOVE THROUGH THE REGION. CEILINGS ARE EXPECTED TO REMAIN
GENERALLY VFR...EXCEPT NEAR THE COAST WHERE THEY COULD BECOME HIGH
END MVFR AT TIMES.

KSEA...VFR. CEILING COULD LOWER TO BKN-OVC040 AT TIMES WITH AREAS OF
VERY LIGHT RAIN. EAST TO SOUTHEAST WIND 8-15 KNOTS EASING TO 5-10
KNOTS THIS MORNING.

&&

.MARINE...OFFSHORE FLOW WILL GRADUALLY EASE TODAY AS A TROUGH OF LOW
PRESSURE MOVES INTO THE WATERS AND WEAKENS. SMALL CRAFT ADVISORY
CONDITIONS WILL CONTINUE OVER THE COASTAL WATERS TODAY...AND THROUGH
THE STRAIT OF JUAN DE FUCA THIS MORNING. WEAKER PRESSURE GRADIENTS
WILL GIVE LIGHTER FLOW ON WEDNESDAY.

A COLD FRONT WILL APPROACH THE WATERS LATE THURSDAY AND THURSDAY
NIGHT. GALE FORCE WINDS ARE POSSIBLE WITH THIS FRONT...MAINLY OVER
THE COASTAL WATERS. A STRONGER SYSTEM ON SATURDAY COULD PRODUCES
GALES OVER THE NORTHERN INLAND WATERS AND STRAIT ENTRANCES IN
ADDITION TO THE COASTAL WATERS. 27

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY COAST...STRAIT OF JUAN DE FUCA.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.

&&

$$

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML






000
FXUS66 KSEW 161046
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 AM PST TUE DEC 16 2014

.SYNOPSIS...WEAKENING WEATHER SYSTEMS TODAY AND WEDNESDAY ARE
EXPECTED TO PRODUCE SPOTTY LIGHT RAIN IN WESTERN WASHINGTON. A
STRONGER PACIFIC FRONTAL SYSTEM IS FORECAST TO ARRIVE LATER THURSDAY
INTO FRIDAY FOR MORE RAIN WITH ANOTHER SYSTEM FOLLOWING OVER THE
WEEKEND.
&&

.SHORT TERM...SATELLITE IMAGES SHOW A NEGATIVE TILTED UPPER TROUGH
OFFSHORE WITH A SPLIT FLOW PATTERN AND THE PRIMARY JET STREAM AIMED
AT CALIFORNIA. A PAIR OF WEAK SHORTWAVES ARE MOVING THROUGH THE
TROUGH AND SHOULD WEAKEN FURTHER AS THEY MOVE ONSHORE GIVEN THE LOW
LEVEL OFFSHORE FLOW. THE FIRST IS PRODUCING SPOTTY LIGHT RAIN IN
SOUTHERLY FLOW ALOFT PER DOPPLER WEATHER RADAR AND SHOULD CONTINUE
INTO TODAY. THE FOLLOWING SHORTWAVE APPROACHING 130W EARLY THIS
MORNING IS EXPECTED TO ARRIVE WEDNESDAY FOR A REPEAT OF SPOTTY RAIN
WITH LIGHT AMOUNTS. BEST POPS WILL BE ALONG THE COAST.

THE NEXT SHORTWAVE NOW NEAR 170W AND PER GUIDANCE...SHOULD BUILD AN
UPPER RIDGE AHEAD OF IT MOVING ONSHORE WEDNESDAY NIGHT INTO
THURSDAY. TIMING ON THE SHORTWAVES ASSOCIATED FRONTAL SYSTEM ARRIVAL
IS A BIT IN QUESTION WITH THE GFS SLOWER THURSDAY VICE THE FASTER
CANADIAN AND ECMWF. GIVEN THE CURRENT SPLIT FLOW...GOING SLOWER MAY
BE THE BETTER SOLUTION. SO THE FORECAST WILL SHOW AN INCREASING
THREAT OF RAIN THROUGHOUT THE DAY WITH THE COAST LIKELY IN THE
AFTERNOON. BUEHNER

.LONG TERM...THE FRONTAL SYSTEM MOVES ONSHORE BY FRIDAY MORNING WITH
RAIN TURNING TO SHOWERS. BY THIS TIME...THE JET HAS RETURNED TO OUR
LATITUDE VS CALIFORNIA. A SHORTWAVE RIDGE AHEAD OF THE NEXT TROUGH
BUILDS ONSHORE SATURDAY BEFORE THE NEXT PACIFIC FRONTAL SYSTEM
ARRIVES BY SUNDAY. AGAIN...PROG TIMING DIFFERS HERE. BUT THE DRIER
DAY OVER THE WEEKEND APPEARS TO BE SATURDAY.

PREVIOUS GUIDANCE OFFERED A PRETTY WET PERIOD SUNDAY INTO MONDAY.
CURRENT GUIDANCE HAS BACKED OFF TO SOME DEGREE. THIS SITUATION BEARS
WATCHING FOR NOW. ALSO KEEPING AN EYE ON A POSSIBLE KONA LOW THAT
WOULD CHANGE THE AMPLITUDE OF THE NORTHERN HEMISPHERE FLOW PATTERN
AND OFFER COOLER AIR FOR THE PACIFIC NW AND PERHAPS SOME SNOW FOR
THE SNOW STARVED MOUNTAINS IN THE LONGER RANGE. STAY TUNED HERE.
BUEHNER

&&

.HYDROLOGY...RIVER FLOODING IS NOT EXPECTED THROUGH AT LEAST
SATURDAY. A WETTER AND WARMER PATTERN WILL PROBABLY DEVELOP SUNDAY
AND MONDAY...AND SOME GUIDANCE SUGGESTING ENOUGH RAIN FOR A THREAT
OF FLOODING ON SOME OF THE MOST FLOOD-PRONE RIVERS. THE LATEST
GUIDANCE IS NOT QUITE AS WET AS PREVIOUS THOUGH. BUEHNER

&&

.AVIATION...AN UPPER LEVEL TROUGH OVER THE OFFSHORE WATERS WILL
PRODUCE SOUTH TO SOUTHWEST FLOW ALOFT OVER WESTERN WASHINGTON TODAY.
LOW LEVEL OFFSHORE FLOW CONTINUES WITH SURFACE HIGH PRESSURE
CENTERED OVER INTERIOR SOUTHERN BRITISH COLUMBIA AND A BROAD TROUGH
OFFSHORE. THE AIR MASS IS STABLE WITH MAINLY MID AND UPPER LEVEL
MOISTURE OVER WESTERN WASHINGTON. LOW LEVELS WILL GRADUALLY MOISTEN
TODAY AS EASTERLY LOW LEVEL FLOW WEAKENS AND AREAS OF VERY LIGHT
RAIN MOVE THROUGH THE REGION. CEILINGS ARE EXPECTED TO REMAIN
GENERALLY VFR...EXCEPT NEAR THE COAST WHERE THEY COULD BECOME HIGH
END MVFR AT TIMES.

KSEA...VFR. CEILING COULD LOWER TO BKN-OVC040 AT TIMES WITH AREAS OF
VERY LIGHT RAIN. EAST TO SOUTHEAST WIND 8-15 KNOTS EASING TO 5-10
KNOTS THIS MORNING.

&&

.MARINE...OFFSHORE FLOW WILL GRADUALLY EASE TODAY AS A TROUGH OF LOW
PRESSURE MOVES INTO THE WATERS AND WEAKENS. SMALL CRAFT ADVISORY
CONDITIONS WILL CONTINUE OVER THE COASTAL WATERS TODAY...AND THROUGH
THE STRAIT OF JUAN DE FUCA THIS MORNING. WEAKER PRESSURE GRADIENTS
WILL GIVE LIGHTER FLOW ON WEDNESDAY.

A COLD FRONT WILL APPROACH THE WATERS LATE THURSDAY AND THURSDAY
NIGHT. GALE FORCE WINDS ARE POSSIBLE WITH THIS FRONT...MAINLY OVER
THE COASTAL WATERS. A STRONGER SYSTEM ON SATURDAY COULD PRODUCES
GALES OVER THE NORTHERN INLAND WATERS AND STRAIT ENTRANCES IN
ADDITION TO THE COASTAL WATERS. 27

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY COAST...STRAIT OF JUAN DE FUCA.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.

&&

$$

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML






000
FXUS66 KSEW 161046
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 AM PST TUE DEC 16 2014

.SYNOPSIS...WEAKENING WEATHER SYSTEMS TODAY AND WEDNESDAY ARE
EXPECTED TO PRODUCE SPOTTY LIGHT RAIN IN WESTERN WASHINGTON. A
STRONGER PACIFIC FRONTAL SYSTEM IS FORECAST TO ARRIVE LATER THURSDAY
INTO FRIDAY FOR MORE RAIN WITH ANOTHER SYSTEM FOLLOWING OVER THE
WEEKEND.
&&

.SHORT TERM...SATELLITE IMAGES SHOW A NEGATIVE TILTED UPPER TROUGH
OFFSHORE WITH A SPLIT FLOW PATTERN AND THE PRIMARY JET STREAM AIMED
AT CALIFORNIA. A PAIR OF WEAK SHORTWAVES ARE MOVING THROUGH THE
TROUGH AND SHOULD WEAKEN FURTHER AS THEY MOVE ONSHORE GIVEN THE LOW
LEVEL OFFSHORE FLOW. THE FIRST IS PRODUCING SPOTTY LIGHT RAIN IN
SOUTHERLY FLOW ALOFT PER DOPPLER WEATHER RADAR AND SHOULD CONTINUE
INTO TODAY. THE FOLLOWING SHORTWAVE APPROACHING 130W EARLY THIS
MORNING IS EXPECTED TO ARRIVE WEDNESDAY FOR A REPEAT OF SPOTTY RAIN
WITH LIGHT AMOUNTS. BEST POPS WILL BE ALONG THE COAST.

THE NEXT SHORTWAVE NOW NEAR 170W AND PER GUIDANCE...SHOULD BUILD AN
UPPER RIDGE AHEAD OF IT MOVING ONSHORE WEDNESDAY NIGHT INTO
THURSDAY. TIMING ON THE SHORTWAVES ASSOCIATED FRONTAL SYSTEM ARRIVAL
IS A BIT IN QUESTION WITH THE GFS SLOWER THURSDAY VICE THE FASTER
CANADIAN AND ECMWF. GIVEN THE CURRENT SPLIT FLOW...GOING SLOWER MAY
BE THE BETTER SOLUTION. SO THE FORECAST WILL SHOW AN INCREASING
THREAT OF RAIN THROUGHOUT THE DAY WITH THE COAST LIKELY IN THE
AFTERNOON. BUEHNER

.LONG TERM...THE FRONTAL SYSTEM MOVES ONSHORE BY FRIDAY MORNING WITH
RAIN TURNING TO SHOWERS. BY THIS TIME...THE JET HAS RETURNED TO OUR
LATITUDE VS CALIFORNIA. A SHORTWAVE RIDGE AHEAD OF THE NEXT TROUGH
BUILDS ONSHORE SATURDAY BEFORE THE NEXT PACIFIC FRONTAL SYSTEM
ARRIVES BY SUNDAY. AGAIN...PROG TIMING DIFFERS HERE. BUT THE DRIER
DAY OVER THE WEEKEND APPEARS TO BE SATURDAY.

PREVIOUS GUIDANCE OFFERED A PRETTY WET PERIOD SUNDAY INTO MONDAY.
CURRENT GUIDANCE HAS BACKED OFF TO SOME DEGREE. THIS SITUATION BEARS
WATCHING FOR NOW. ALSO KEEPING AN EYE ON A POSSIBLE KONA LOW THAT
WOULD CHANGE THE AMPLITUDE OF THE NORTHERN HEMISPHERE FLOW PATTERN
AND OFFER COOLER AIR FOR THE PACIFIC NW AND PERHAPS SOME SNOW FOR
THE SNOW STARVED MOUNTAINS IN THE LONGER RANGE. STAY TUNED HERE.
BUEHNER

&&

.HYDROLOGY...RIVER FLOODING IS NOT EXPECTED THROUGH AT LEAST
SATURDAY. A WETTER AND WARMER PATTERN WILL PROBABLY DEVELOP SUNDAY
AND MONDAY...AND SOME GUIDANCE SUGGESTING ENOUGH RAIN FOR A THREAT
OF FLOODING ON SOME OF THE MOST FLOOD-PRONE RIVERS. THE LATEST
GUIDANCE IS NOT QUITE AS WET AS PREVIOUS THOUGH. BUEHNER

&&

.AVIATION...AN UPPER LEVEL TROUGH OVER THE OFFSHORE WATERS WILL
PRODUCE SOUTH TO SOUTHWEST FLOW ALOFT OVER WESTERN WASHINGTON TODAY.
LOW LEVEL OFFSHORE FLOW CONTINUES WITH SURFACE HIGH PRESSURE
CENTERED OVER INTERIOR SOUTHERN BRITISH COLUMBIA AND A BROAD TROUGH
OFFSHORE. THE AIR MASS IS STABLE WITH MAINLY MID AND UPPER LEVEL
MOISTURE OVER WESTERN WASHINGTON. LOW LEVELS WILL GRADUALLY MOISTEN
TODAY AS EASTERLY LOW LEVEL FLOW WEAKENS AND AREAS OF VERY LIGHT
RAIN MOVE THROUGH THE REGION. CEILINGS ARE EXPECTED TO REMAIN
GENERALLY VFR...EXCEPT NEAR THE COAST WHERE THEY COULD BECOME HIGH
END MVFR AT TIMES.

KSEA...VFR. CEILING COULD LOWER TO BKN-OVC040 AT TIMES WITH AREAS OF
VERY LIGHT RAIN. EAST TO SOUTHEAST WIND 8-15 KNOTS EASING TO 5-10
KNOTS THIS MORNING.

&&

.MARINE...OFFSHORE FLOW WILL GRADUALLY EASE TODAY AS A TROUGH OF LOW
PRESSURE MOVES INTO THE WATERS AND WEAKENS. SMALL CRAFT ADVISORY
CONDITIONS WILL CONTINUE OVER THE COASTAL WATERS TODAY...AND THROUGH
THE STRAIT OF JUAN DE FUCA THIS MORNING. WEAKER PRESSURE GRADIENTS
WILL GIVE LIGHTER FLOW ON WEDNESDAY.

A COLD FRONT WILL APPROACH THE WATERS LATE THURSDAY AND THURSDAY
NIGHT. GALE FORCE WINDS ARE POSSIBLE WITH THIS FRONT...MAINLY OVER
THE COASTAL WATERS. A STRONGER SYSTEM ON SATURDAY COULD PRODUCES
GALES OVER THE NORTHERN INLAND WATERS AND STRAIT ENTRANCES IN
ADDITION TO THE COASTAL WATERS. 27

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY COAST...STRAIT OF JUAN DE FUCA.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.

&&

$$

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML






000
FXUS66 KSEW 161046
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 AM PST TUE DEC 16 2014

.SYNOPSIS...WEAKENING WEATHER SYSTEMS TODAY AND WEDNESDAY ARE
EXPECTED TO PRODUCE SPOTTY LIGHT RAIN IN WESTERN WASHINGTON. A
STRONGER PACIFIC FRONTAL SYSTEM IS FORECAST TO ARRIVE LATER THURSDAY
INTO FRIDAY FOR MORE RAIN WITH ANOTHER SYSTEM FOLLOWING OVER THE
WEEKEND.
&&

.SHORT TERM...SATELLITE IMAGES SHOW A NEGATIVE TILTED UPPER TROUGH
OFFSHORE WITH A SPLIT FLOW PATTERN AND THE PRIMARY JET STREAM AIMED
AT CALIFORNIA. A PAIR OF WEAK SHORTWAVES ARE MOVING THROUGH THE
TROUGH AND SHOULD WEAKEN FURTHER AS THEY MOVE ONSHORE GIVEN THE LOW
LEVEL OFFSHORE FLOW. THE FIRST IS PRODUCING SPOTTY LIGHT RAIN IN
SOUTHERLY FLOW ALOFT PER DOPPLER WEATHER RADAR AND SHOULD CONTINUE
INTO TODAY. THE FOLLOWING SHORTWAVE APPROACHING 130W EARLY THIS
MORNING IS EXPECTED TO ARRIVE WEDNESDAY FOR A REPEAT OF SPOTTY RAIN
WITH LIGHT AMOUNTS. BEST POPS WILL BE ALONG THE COAST.

THE NEXT SHORTWAVE NOW NEAR 170W AND PER GUIDANCE...SHOULD BUILD AN
UPPER RIDGE AHEAD OF IT MOVING ONSHORE WEDNESDAY NIGHT INTO
THURSDAY. TIMING ON THE SHORTWAVES ASSOCIATED FRONTAL SYSTEM ARRIVAL
IS A BIT IN QUESTION WITH THE GFS SLOWER THURSDAY VICE THE FASTER
CANADIAN AND ECMWF. GIVEN THE CURRENT SPLIT FLOW...GOING SLOWER MAY
BE THE BETTER SOLUTION. SO THE FORECAST WILL SHOW AN INCREASING
THREAT OF RAIN THROUGHOUT THE DAY WITH THE COAST LIKELY IN THE
AFTERNOON. BUEHNER

.LONG TERM...THE FRONTAL SYSTEM MOVES ONSHORE BY FRIDAY MORNING WITH
RAIN TURNING TO SHOWERS. BY THIS TIME...THE JET HAS RETURNED TO OUR
LATITUDE VS CALIFORNIA. A SHORTWAVE RIDGE AHEAD OF THE NEXT TROUGH
BUILDS ONSHORE SATURDAY BEFORE THE NEXT PACIFIC FRONTAL SYSTEM
ARRIVES BY SUNDAY. AGAIN...PROG TIMING DIFFERS HERE. BUT THE DRIER
DAY OVER THE WEEKEND APPEARS TO BE SATURDAY.

PREVIOUS GUIDANCE OFFERED A PRETTY WET PERIOD SUNDAY INTO MONDAY.
CURRENT GUIDANCE HAS BACKED OFF TO SOME DEGREE. THIS SITUATION BEARS
WATCHING FOR NOW. ALSO KEEPING AN EYE ON A POSSIBLE KONA LOW THAT
WOULD CHANGE THE AMPLITUDE OF THE NORTHERN HEMISPHERE FLOW PATTERN
AND OFFER COOLER AIR FOR THE PACIFIC NW AND PERHAPS SOME SNOW FOR
THE SNOW STARVED MOUNTAINS IN THE LONGER RANGE. STAY TUNED HERE.
BUEHNER

&&

.HYDROLOGY...RIVER FLOODING IS NOT EXPECTED THROUGH AT LEAST
SATURDAY. A WETTER AND WARMER PATTERN WILL PROBABLY DEVELOP SUNDAY
AND MONDAY...AND SOME GUIDANCE SUGGESTING ENOUGH RAIN FOR A THREAT
OF FLOODING ON SOME OF THE MOST FLOOD-PRONE RIVERS. THE LATEST
GUIDANCE IS NOT QUITE AS WET AS PREVIOUS THOUGH. BUEHNER

&&

.AVIATION...AN UPPER LEVEL TROUGH OVER THE OFFSHORE WATERS WILL
PRODUCE SOUTH TO SOUTHWEST FLOW ALOFT OVER WESTERN WASHINGTON TODAY.
LOW LEVEL OFFSHORE FLOW CONTINUES WITH SURFACE HIGH PRESSURE
CENTERED OVER INTERIOR SOUTHERN BRITISH COLUMBIA AND A BROAD TROUGH
OFFSHORE. THE AIR MASS IS STABLE WITH MAINLY MID AND UPPER LEVEL
MOISTURE OVER WESTERN WASHINGTON. LOW LEVELS WILL GRADUALLY MOISTEN
TODAY AS EASTERLY LOW LEVEL FLOW WEAKENS AND AREAS OF VERY LIGHT
RAIN MOVE THROUGH THE REGION. CEILINGS ARE EXPECTED TO REMAIN
GENERALLY VFR...EXCEPT NEAR THE COAST WHERE THEY COULD BECOME HIGH
END MVFR AT TIMES.

KSEA...VFR. CEILING COULD LOWER TO BKN-OVC040 AT TIMES WITH AREAS OF
VERY LIGHT RAIN. EAST TO SOUTHEAST WIND 8-15 KNOTS EASING TO 5-10
KNOTS THIS MORNING.

&&

.MARINE...OFFSHORE FLOW WILL GRADUALLY EASE TODAY AS A TROUGH OF LOW
PRESSURE MOVES INTO THE WATERS AND WEAKENS. SMALL CRAFT ADVISORY
CONDITIONS WILL CONTINUE OVER THE COASTAL WATERS TODAY...AND THROUGH
THE STRAIT OF JUAN DE FUCA THIS MORNING. WEAKER PRESSURE GRADIENTS
WILL GIVE LIGHTER FLOW ON WEDNESDAY.

A COLD FRONT WILL APPROACH THE WATERS LATE THURSDAY AND THURSDAY
NIGHT. GALE FORCE WINDS ARE POSSIBLE WITH THIS FRONT...MAINLY OVER
THE COASTAL WATERS. A STRONGER SYSTEM ON SATURDAY COULD PRODUCES
GALES OVER THE NORTHERN INLAND WATERS AND STRAIT ENTRANCES IN
ADDITION TO THE COASTAL WATERS. 27

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY COAST...STRAIT OF JUAN DE FUCA.
     SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.

&&

$$

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML






000
FXUS66 KOTX 161025
AFDOTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
225 AM PST TUE DEC 16 2014

.SYNOPSIS...
A WEAK STORM SYSTEM WILL BRING LIGHT ACCUMULATIONS OF SNOW
TODAY TO THE AREAS NEAR THE CASCADES AND LIGHT RAIN TO THE
COLUMBIA BASIN. A MORE ACTIVE WEATHER PATTERN WILL DEVELOP LATE
IN THE WEEK WITH GENERALLY MOUNTAIN SNOW AND VALLEY RAIN OR
MINIMALLY ACCUMULATING SNOW.



&&

.DISCUSSION...
TODAY THROUGH WEDNESDAY...THROUGH THIS PORTION OF THE FORECAST
PERIOD SEVERAL WEAK FRONTAL SYSTEMS WILL TRY, BUT HAVE
DIFFICULTY, MOVING THROUGH A STRONG RIDGE OF HIGH PRESSURE IN A
SPLIT FLOW PATTERN. THE FIRST WEAK WAVE IS EXPECTED TO MOVE ALONG
THE EAST SLOPES OF THE CASCADES THIS MORNING, THEN WEAKEN FURTHER
AS IT TRACKS EAST ACROSS MAINLY THE NORTHERN ZONES. AS MENTIONED
THIS WAVE IS FAIRLY WEAK, BUT DOES HAVE SOME MOISTURE WITH IT AS
PWAT`S INCREASING TO 150-170% OF NORMAL. WHILE PRECIPITATION IS
EXPECTED ALONG THE EAST SLOPES AND THE NORTHERN MOUNTAINS ANY
AMOUNTS SHOULD BE RATHER LIGHT, AND ON THE ORDER OF A TRACE IN THE
BASIN TO AROUND A TENTH OF AN INCH IN THE MOUNTAINS.

WITH SUNNY SKIES TEMPERATURES WERE ABLE TO WARM NICELY MONDAY
AFTERNOON AND THE TEMPERATURES WERE NOT ABLE TO RADIATE VERY
EFFICIENTLY AS THE CLOUDS BEGAN TO MOVE IN SOON AFTER SUNSET. THIS
HAS KEPT TEMPERATURES ACROSS THE LOWER ELEVATION AT OR ABOVE
FREEZING SO FAR. SOME WET BULBING IS EXPECTED ACROSS THE LOWER
ELEVATIONS OF THE BASIN, WATERVILLE PLATEAU, WENATCHEE VALLEY AND
SOME OF THE MOUNTAIN VALLEYS FOR PRECIPITATION STARTING AS LIGHT
SNOW BEFORE TURNING OVER TO RAIN, WITH SNOW EXPECTED FOR THE
MOUNTAINS. IT ALSO LOOKS LIKE THERE MAY BE SOME LOCALIZED POCKETS
OF FREEZING RAIN POSSIBLE FOR THE WATERVILLE PLATEAU AND THE UPPER
BASIN NEAR THE COLUMBIA RIVER. SOME OF THE HIGHER ELEVATIONS IN
THE CASCADES COULD SEE 1-2 INCHES OF SNOW. WARM AIR ADVECTION WILL
BE HAMPERED BY INCREASED CLOUD COVER AND TEMPERATURES WILL BE 2-4
DEGREES COOLER TODAY.

SOME LOW END POPS WERE KEPT IN THE FORECAST TONIGHT AND EARLY
WEDNESDAY FOR THE NORTHERN MOUNTAINS WITH UP-SLOPING FLOW AND
ABUNDANT LOW LEVEL MOISTURE, BUT AGAIN ACCUMULATIONS SHOULD BE
VERY LIGHT. OTHERWISE EXPECT AN INCREASING CHANCE FOR FOG AND LOW
CLOUD DEVELOPMENT. BY LATE WEDNESDAY AFTERNOON ANOTHER VERY WEAK
FRONT WILL BEGIN TO INCREASE MOISTURE FOR THE CASCADES. THIS WAVE
LOOKS WEAKER THAN THE ONE TODAY AND EXPECT ONLY LIGHT
ACCUMULATIONS AND MAINLY NEAR THE CREST. /TOBIN

WEDNESDAY NIGHT AND THURSDAY...ONE WEAK SYSTEM PUSHING THROUGH AN
AREA OF HIGH PRESSURE. THIS UPPER LEVEL TROUGH WITH REMNANTS OF
PACIFIC MOISTURE WILL DISSIPATE AS IT MOVES EAST OF THE CASCADES.
UNDER LIGHT WINDS AND WEAK ISENTROPIC LIFT, THE WEAK WARM FRONT
WILL LIFT NORTH WITH WARMING WITH TIME. EXPECT LIGHT SNOW CHANGING
TO VALLEY RAIN BY THURSDAY WITH THE MAIN AREA ACROSS EXTREME
EASTERN WASHINGTON AND NORTH IDAHO. THE 850MB 0C LINE STAYS FROM
KMWH-LWS. IT LOOKS TO BE A SLOW MOVER WITH LIGHT PRECIPITATION
AMOUNTS. THERE LOOKS TO BE A POSSIBLE 1 INCH IN THE NORTHERN
VALLEYS WHILE THE NORTHERN MOUNTAINS MAY EXPERIENCE 1-2 INCHES.
HIGH PRESSURE BUILDS BACK IN BY LATE THURSDAY BRINGING A BREAK IN
THE PRECIPITATION.

THURSDAY NIGHT THROUGH FRIDAY NIGHT...NEXT SYSTEM REACHES THE COAST
AS A WARM FRONT PUSHES EAST OF CASCADES LATE THURSDAY NIGHT. THIS
ONE LOOKS TO BE A LITTLE STRONGER SYSTEM AND A LITTLE WARMER.
PRECIPITATION TYPE WILL BE TRICKY WITH A POSSIBLE WINTRY MIX. THE
850MB 0C LINE SPANS FROM KEAT-KDEW BY 12Z FRIDAY, AND CONTINUES TO
PUSH NORTH. THIS WOULD BRING MAINLY RAIN TO THE COLUMBIA BASIN AND
LOWER VALLEYS, WHILE LIGHT SNOW IS POSSIBLE TO THE NORTH. THERE
LOOKS TO BE A POSSIBLE 1-2 INCHES IN THE NORTHERN VALLEYS, WHILE
THE NORTHERN MOUNTAINS COULD SEE 1-3 INCHES. AN OCCLUDED FRONT
ARRIVES FRIDAY AFTERNOON/EVE AND SWEEPS THROUGH THE REGION WITH
LIGHT WINDS. THEN DRYING OCCURS BEHIND THE FRONT FRIDAY NIGHT WITH
A BRIEF BREAK IN THE PRECIPITATION.

SATURDAY THROUGH MONDAY...THIS LOOKS TO BE A WETTEST PERIOD. AN
ATMOSPHERIC RIVER SETS UP AND TAKES AIM ON THE PACIFIC NW. TIMING
OF THE ONSET IS A LITTLE UNCLEAR FOR SATURDAY BETWEEN THE ECMWF
AND GFS, WITH THE GFS BEING THE SLOWER SOLUTION. BUT BY 12Z
SUNDAY, THE MODELS INDICATE A WET WESTERLY FLOW SPREADING
PLENTIFUL MOISTURE ACROSS THE INLAND NW WHICH WILL CONTINUE INTO
EARLY NEXT WEEK. THERE IS A POTENTIAL FOR MODERATE SNOW IN THE
EAST SLOPES OF THE NORTHERN CASCADES AND NORTHERN MOUNTAINS AT THE
ONSET. THEN THE WARMING INCREASES AND LOOKS TO BE A MAINLY
RAIN/HIGH MOUNTAIN SNOW EVENT BY SUNDAY AFTERNOON. WINDS WILL
INCREASE BY SUNDAY EVENING WITH SPEEDS 20-30 KTS ACROSS THE
COLUMBIA BASIN. THE 850MB 0C LINE PUSHES TO THE CANADIAN BORDER
ON SUNDAY WHILE TEMPS OF +5C TO +7C ARE FOUND TO THE SOUTH. SUNDAY
APPEARS TO BE THE WARMEST DAY WITH WIDESPREAD 40S AND A FEW 50S
POSSIBLE. OPTED TO RAISE POPS FOR THIS EVENT AND TEMPERATURES
ESPECIALLY FOR SATURDAY NIGHT AND SUNDAY. THERE ARE SOME
INDICATIONS THAT THIS HOSE OF MOISTURE WILL SLIDE SOUTHWARD LATE
MONDAY, FOLLOWED BY A GRADUAL COOLING FROM THE NORTH. /RFOX.


&&

.AVIATION...
06Z TAFS: A WEAK UPPER LEVEL DISTURBANCE WILL PUSH INTO THE REGION
OVERNIGHT. BEST CHANCES FOR PRECIP WILL BE AT KEAT AND KMWH AFTER
09Z. PRECIP TYPE IS EXPECTED TO BE PREDOMINATELY RAIN, BUT A
LITTLE BIT OF SNOW MIXED IN WILL BE POSSIBLE THROUGH THE MORNING
HOURS. EXPECT CIGS TO DETERIORATE INTO MVFR CATEGORY AT THESE
LOCATIONS AS WELL. LOWER LEVELS OF THE ATMOSPHERE WILL HAVE A
HARDER TIME MOISTENING UP AT KGEG, KSFF, KCOE, KPUW AND KLWS DUE
TO A PERSISTENT DRIER EASTERLY WINDS ACROSS THESE TAF LOCATIONS.
FLURRIES WILL BE POSSIBLE AT THESE LOCATIONS WITH CIGS EXPECTED TO
LOWER DOWN TO BETWEEN 2-5 KFT AGL DEPENDING ON THE ELEVATION OF
THE TAF SITE. /SVH



&&

.PRELIMINARY POINT TEMPS/POPS...
SPOKANE        36  29  38  32  37  31 /  10  10  10  30  30  10
COEUR D`ALENE  37  30  40  33  38  31 /  10  10  10  40  40  10
PULLMAN        40  29  42  32  41  32 /  10  10  10  30  30  10
LEWISTON       43  32  42  35  43  34 /  20  10  10  30  30  10
COLVILLE       34  28  36  31  37  31 /  40  30  20  30  30  20
SANDPOINT      35  28  36  30  36  31 /  10  20  10  40  40  20
KELLOGG        37  30  38  31  36  30 /  10  20  10  40  40  20
MOSES LAKE     37  28  38  28  38  30 /  60  10  20  20  10  30
WENATCHEE      36  31  37  30  36  31 /  70  10  30  30  10  30
OMAK           34  26  34  27  33  28 /  60  30  40  30  10  30

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
WA...AIR STAGNATION ADVISORY UNTIL NOON PST FRIDAY FOR EAST SLOPES
     NORTHERN CASCADES-MOSES LAKE AREA-NORTHEAST MOUNTAINS-
     OKANOGAN HIGHLANDS-OKANOGAN VALLEY-UPPER COLUMBIA BASIN-
     WATERVILLE PLATEAU-WENATCHEE AREA.

&&

$$



000
FXUS66 KOTX 161025
AFDOTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
225 AM PST TUE DEC 16 2014

.SYNOPSIS...
A WEAK STORM SYSTEM WILL BRING LIGHT ACCUMULATIONS OF SNOW
TODAY TO THE AREAS NEAR THE CASCADES AND LIGHT RAIN TO THE
COLUMBIA BASIN. A MORE ACTIVE WEATHER PATTERN WILL DEVELOP LATE
IN THE WEEK WITH GENERALLY MOUNTAIN SNOW AND VALLEY RAIN OR
MINIMALLY ACCUMULATING SNOW.



&&

.DISCUSSION...
TODAY THROUGH WEDNESDAY...THROUGH THIS PORTION OF THE FORECAST
PERIOD SEVERAL WEAK FRONTAL SYSTEMS WILL TRY, BUT HAVE
DIFFICULTY, MOVING THROUGH A STRONG RIDGE OF HIGH PRESSURE IN A
SPLIT FLOW PATTERN. THE FIRST WEAK WAVE IS EXPECTED TO MOVE ALONG
THE EAST SLOPES OF THE CASCADES THIS MORNING, THEN WEAKEN FURTHER
AS IT TRACKS EAST ACROSS MAINLY THE NORTHERN ZONES. AS MENTIONED
THIS WAVE IS FAIRLY WEAK, BUT DOES HAVE SOME MOISTURE WITH IT AS
PWAT`S INCREASING TO 150-170% OF NORMAL. WHILE PRECIPITATION IS
EXPECTED ALONG THE EAST SLOPES AND THE NORTHERN MOUNTAINS ANY
AMOUNTS SHOULD BE RATHER LIGHT, AND ON THE ORDER OF A TRACE IN THE
BASIN TO AROUND A TENTH OF AN INCH IN THE MOUNTAINS.

WITH SUNNY SKIES TEMPERATURES WERE ABLE TO WARM NICELY MONDAY
AFTERNOON AND THE TEMPERATURES WERE NOT ABLE TO RADIATE VERY
EFFICIENTLY AS THE CLOUDS BEGAN TO MOVE IN SOON AFTER SUNSET. THIS
HAS KEPT TEMPERATURES ACROSS THE LOWER ELEVATION AT OR ABOVE
FREEZING SO FAR. SOME WET BULBING IS EXPECTED ACROSS THE LOWER
ELEVATIONS OF THE BASIN, WATERVILLE PLATEAU, WENATCHEE VALLEY AND
SOME OF THE MOUNTAIN VALLEYS FOR PRECIPITATION STARTING AS LIGHT
SNOW BEFORE TURNING OVER TO RAIN, WITH SNOW EXPECTED FOR THE
MOUNTAINS. IT ALSO LOOKS LIKE THERE MAY BE SOME LOCALIZED POCKETS
OF FREEZING RAIN POSSIBLE FOR THE WATERVILLE PLATEAU AND THE UPPER
BASIN NEAR THE COLUMBIA RIVER. SOME OF THE HIGHER ELEVATIONS IN
THE CASCADES COULD SEE 1-2 INCHES OF SNOW. WARM AIR ADVECTION WILL
BE HAMPERED BY INCREASED CLOUD COVER AND TEMPERATURES WILL BE 2-4
DEGREES COOLER TODAY.

SOME LOW END POPS WERE KEPT IN THE FORECAST TONIGHT AND EARLY
WEDNESDAY FOR THE NORTHERN MOUNTAINS WITH UP-SLOPING FLOW AND
ABUNDANT LOW LEVEL MOISTURE, BUT AGAIN ACCUMULATIONS SHOULD BE
VERY LIGHT. OTHERWISE EXPECT AN INCREASING CHANCE FOR FOG AND LOW
CLOUD DEVELOPMENT. BY LATE WEDNESDAY AFTERNOON ANOTHER VERY WEAK
FRONT WILL BEGIN TO INCREASE MOISTURE FOR THE CASCADES. THIS WAVE
LOOKS WEAKER THAN THE ONE TODAY AND EXPECT ONLY LIGHT
ACCUMULATIONS AND MAINLY NEAR THE CREST. /TOBIN

WEDNESDAY NIGHT AND THURSDAY...ONE WEAK SYSTEM PUSHING THROUGH AN
AREA OF HIGH PRESSURE. THIS UPPER LEVEL TROUGH WITH REMNANTS OF
PACIFIC MOISTURE WILL DISSIPATE AS IT MOVES EAST OF THE CASCADES.
UNDER LIGHT WINDS AND WEAK ISENTROPIC LIFT, THE WEAK WARM FRONT
WILL LIFT NORTH WITH WARMING WITH TIME. EXPECT LIGHT SNOW CHANGING
TO VALLEY RAIN BY THURSDAY WITH THE MAIN AREA ACROSS EXTREME
EASTERN WASHINGTON AND NORTH IDAHO. THE 850MB 0C LINE STAYS FROM
KMWH-LWS. IT LOOKS TO BE A SLOW MOVER WITH LIGHT PRECIPITATION
AMOUNTS. THERE LOOKS TO BE A POSSIBLE 1 INCH IN THE NORTHERN
VALLEYS WHILE THE NORTHERN MOUNTAINS MAY EXPERIENCE 1-2 INCHES.
HIGH PRESSURE BUILDS BACK IN BY LATE THURSDAY BRINGING A BREAK IN
THE PRECIPITATION.

THURSDAY NIGHT THROUGH FRIDAY NIGHT...NEXT SYSTEM REACHES THE COAST
AS A WARM FRONT PUSHES EAST OF CASCADES LATE THURSDAY NIGHT. THIS
ONE LOOKS TO BE A LITTLE STRONGER SYSTEM AND A LITTLE WARMER.
PRECIPITATION TYPE WILL BE TRICKY WITH A POSSIBLE WINTRY MIX. THE
850MB 0C LINE SPANS FROM KEAT-KDEW BY 12Z FRIDAY, AND CONTINUES TO
PUSH NORTH. THIS WOULD BRING MAINLY RAIN TO THE COLUMBIA BASIN AND
LOWER VALLEYS, WHILE LIGHT SNOW IS POSSIBLE TO THE NORTH. THERE
LOOKS TO BE A POSSIBLE 1-2 INCHES IN THE NORTHERN VALLEYS, WHILE
THE NORTHERN MOUNTAINS COULD SEE 1-3 INCHES. AN OCCLUDED FRONT
ARRIVES FRIDAY AFTERNOON/EVE AND SWEEPS THROUGH THE REGION WITH
LIGHT WINDS. THEN DRYING OCCURS BEHIND THE FRONT FRIDAY NIGHT WITH
A BRIEF BREAK IN THE PRECIPITATION.

SATURDAY THROUGH MONDAY...THIS LOOKS TO BE A WETTEST PERIOD. AN
ATMOSPHERIC RIVER SETS UP AND TAKES AIM ON THE PACIFIC NW. TIMING
OF THE ONSET IS A LITTLE UNCLEAR FOR SATURDAY BETWEEN THE ECMWF
AND GFS, WITH THE GFS BEING THE SLOWER SOLUTION. BUT BY 12Z
SUNDAY, THE MODELS INDICATE A WET WESTERLY FLOW SPREADING
PLENTIFUL MOISTURE ACROSS THE INLAND NW WHICH WILL CONTINUE INTO
EARLY NEXT WEEK. THERE IS A POTENTIAL FOR MODERATE SNOW IN THE
EAST SLOPES OF THE NORTHERN CASCADES AND NORTHERN MOUNTAINS AT THE
ONSET. THEN THE WARMING INCREASES AND LOOKS TO BE A MAINLY
RAIN/HIGH MOUNTAIN SNOW EVENT BY SUNDAY AFTERNOON. WINDS WILL
INCREASE BY SUNDAY EVENING WITH SPEEDS 20-30 KTS ACROSS THE
COLUMBIA BASIN. THE 850MB 0C LINE PUSHES TO THE CANADIAN BORDER
ON SUNDAY WHILE TEMPS OF +5C TO +7C ARE FOUND TO THE SOUTH. SUNDAY
APPEARS TO BE THE WARMEST DAY WITH WIDESPREAD 40S AND A FEW 50S
POSSIBLE. OPTED TO RAISE POPS FOR THIS EVENT AND TEMPERATURES
ESPECIALLY FOR SATURDAY NIGHT AND SUNDAY. THERE ARE SOME
INDICATIONS THAT THIS HOSE OF MOISTURE WILL SLIDE SOUTHWARD LATE
MONDAY, FOLLOWED BY A GRADUAL COOLING FROM THE NORTH. /RFOX.


&&

.AVIATION...
06Z TAFS: A WEAK UPPER LEVEL DISTURBANCE WILL PUSH INTO THE REGION
OVERNIGHT. BEST CHANCES FOR PRECIP WILL BE AT KEAT AND KMWH AFTER
09Z. PRECIP TYPE IS EXPECTED TO BE PREDOMINATELY RAIN, BUT A
LITTLE BIT OF SNOW MIXED IN WILL BE POSSIBLE THROUGH THE MORNING
HOURS. EXPECT CIGS TO DETERIORATE INTO MVFR CATEGORY AT THESE
LOCATIONS AS WELL. LOWER LEVELS OF THE ATMOSPHERE WILL HAVE A
HARDER TIME MOISTENING UP AT KGEG, KSFF, KCOE, KPUW AND KLWS DUE
TO A PERSISTENT DRIER EASTERLY WINDS ACROSS THESE TAF LOCATIONS.
FLURRIES WILL BE POSSIBLE AT THESE LOCATIONS WITH CIGS EXPECTED TO
LOWER DOWN TO BETWEEN 2-5 KFT AGL DEPENDING ON THE ELEVATION OF
THE TAF SITE. /SVH



&&

.PRELIMINARY POINT TEMPS/POPS...
SPOKANE        36  29  38  32  37  31 /  10  10  10  30  30  10
COEUR D`ALENE  37  30  40  33  38  31 /  10  10  10  40  40  10
PULLMAN        40  29  42  32  41  32 /  10  10  10  30  30  10
LEWISTON       43  32  42  35  43  34 /  20  10  10  30  30  10
COLVILLE       34  28  36  31  37  31 /  40  30  20  30  30  20
SANDPOINT      35  28  36  30  36  31 /  10  20  10  40  40  20
KELLOGG        37  30  38  31  36  30 /  10  20  10  40  40  20
MOSES LAKE     37  28  38  28  38  30 /  60  10  20  20  10  30
WENATCHEE      36  31  37  30  36  31 /  70  10  30  30  10  30
OMAK           34  26  34  27  33  28 /  60  30  40  30  10  30

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
WA...AIR STAGNATION ADVISORY UNTIL NOON PST FRIDAY FOR EAST SLOPES
     NORTHERN CASCADES-MOSES LAKE AREA-NORTHEAST MOUNTAINS-
     OKANOGAN HIGHLANDS-OKANOGAN VALLEY-UPPER COLUMBIA BASIN-
     WATERVILLE PLATEAU-WENATCHEE AREA.

&&

$$




000
FXUS66 KOTX 160649
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1049 PM PST MON DEC 15 2014

.SYNOPSIS...
A weak storm system will bring light accumulations of snow
tonight and Tuesday to the areas near the Cascades. A more active
weather pattern will develop late in the week with generally
mountain snow and valley rain or minimally accumulating snow.


&&

.DISCUSSION...
Forecast was updated this evening to warm low temperatures a
little bit mainly for the basin and in the Wenatchee Area.
Temperatures have not cooled as much as was anticipated due to
increasing high and mid level cloud cover. This is expected to
keep surface temperatures above freezing for much of the Moses
Lake Area and the southern portions of the Upper Columbia Basin.
The freezing rain threat looks slim due to these warmer surface
temperatures late this evening.

The weak upper level disturbance is beginning to push across
Oregon and light precip will begin to push into the region
overnight into Tuesday morning. Best chance for precip will still be
across the western half of the forecast area. The Wenatchee Area
and Moses Lake Area looks to start out as rain due to surface
temps a couple of degrees above freezing. These temperatures will
drop due to wet bulb cooling effects and some snow will be
possible during this process; however, it appears unlikely that
snow will accumulate at the lower elevations across these areas.
Best chances for accumulating snow will be along the East Slopes
of the Northern Cascades where up to 1-2 inches will be possible
through Tuesday. /SVH


&&

.AVIATION...
06Z TAFS: A weak upper level disturbance will push into the region
overnight. Best chances for precip will be at KEAT and KMWH after
09Z. Precip type is expected to be predominately rain, but a
little bit of snow mixed in will be possible through the morning
hours. Expect cigs to deteriorate into MVFR category at these
locations as well. Lower levels of the atmosphere will have a
harder time moistening up at KGEG, KSFF, KCOE, KPUW and KLWS due
to a persistent drier easterly winds across these TAF locations.
Flurries will be possible at these locations with cigs expected to
lower down to between 2-5 kft agl depending on the elevation of
the TAF site. /SVH


&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        40  29  35  29  38  30 /  10  10  10  10  20  30
Coeur d`Alene  41  28  35  30  40  31 /   0   0  10  10  20  40
Pullman        42  32  40  29  42  31 /  10  10  10  10  20  30
Lewiston       42  34  41  32  42  33 /  10  10  20  10  10  30
Colville       38  26  33  27  36  29 /   0   0  40  30  20  30
Sandpoint      37  25  33  28  36  29 /   0   0  10  20  10  40
Kellogg        39  26  35  30  38  31 /   0   0  10  20  10  40
Moses Lake     41  32  36  27  38  26 /  30  30  60  10  30  20
Wenatchee      38  33  35  31  37  29 /  40  40  70  10  30  30
Omak           35  25  33  26  34  25 /  10  10  60  30  40  30

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$




000
FXUS66 KOTX 160649
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1049 PM PST MON DEC 15 2014

.SYNOPSIS...
A weak storm system will bring light accumulations of snow
tonight and Tuesday to the areas near the Cascades. A more active
weather pattern will develop late in the week with generally
mountain snow and valley rain or minimally accumulating snow.


&&

.DISCUSSION...
Forecast was updated this evening to warm low temperatures a
little bit mainly for the basin and in the Wenatchee Area.
Temperatures have not cooled as much as was anticipated due to
increasing high and mid level cloud cover. This is expected to
keep surface temperatures above freezing for much of the Moses
Lake Area and the southern portions of the Upper Columbia Basin.
The freezing rain threat looks slim due to these warmer surface
temperatures late this evening.

The weak upper level disturbance is beginning to push across
Oregon and light precip will begin to push into the region
overnight into Tuesday morning. Best chance for precip will still be
across the western half of the forecast area. The Wenatchee Area
and Moses Lake Area looks to start out as rain due to surface
temps a couple of degrees above freezing. These temperatures will
drop due to wet bulb cooling effects and some snow will be
possible during this process; however, it appears unlikely that
snow will accumulate at the lower elevations across these areas.
Best chances for accumulating snow will be along the East Slopes
of the Northern Cascades where up to 1-2 inches will be possible
through Tuesday. /SVH


&&

.AVIATION...
06Z TAFS: A weak upper level disturbance will push into the region
overnight. Best chances for precip will be at KEAT and KMWH after
09Z. Precip type is expected to be predominately rain, but a
little bit of snow mixed in will be possible through the morning
hours. Expect cigs to deteriorate into MVFR category at these
locations as well. Lower levels of the atmosphere will have a
harder time moistening up at KGEG, KSFF, KCOE, KPUW and KLWS due
to a persistent drier easterly winds across these TAF locations.
Flurries will be possible at these locations with cigs expected to
lower down to between 2-5 kft agl depending on the elevation of
the TAF site. /SVH


&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        40  29  35  29  38  30 /  10  10  10  10  20  30
Coeur d`Alene  41  28  35  30  40  31 /   0   0  10  10  20  40
Pullman        42  32  40  29  42  31 /  10  10  10  10  20  30
Lewiston       42  34  41  32  42  33 /  10  10  20  10  10  30
Colville       38  26  33  27  36  29 /   0   0  40  30  20  30
Sandpoint      37  25  33  28  36  29 /   0   0  10  20  10  40
Kellogg        39  26  35  30  38  31 /   0   0  10  20  10  40
Moses Lake     41  32  36  27  38  26 /  30  30  60  10  30  20
Wenatchee      38  33  35  31  37  29 /  40  40  70  10  30  30
Omak           35  25  33  26  34  25 /  10  10  60  30  40  30

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Air Stagnation Advisory until Noon PST Friday for East Slopes
     Northern Cascades-Moses Lake Area-Northeast Mountains-
     Okanogan Highlands-Okanogan Valley-Upper Columbia Basin-
     Waterville Plateau-Wenatchee Area.

&&

$$





000
FXUS66 KPQR 160439
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
838 PM PST MON DEC 15 2014

.SYNOPSIS...A SERIES OF WEAK FRONTAL SYSTEMS CONTINUES TO MOVE
ONSHORE...WITH THE LATEST PIVOTING THROUGH WESTERN OREGON THIS
EVENING. HIGH PRESSURE REMAINS EAST OF THE CASCADES...PRODUCING
LOW-LEVEL OFFSHORE FLOW AND KEEPING THE AIR MASS DRY ENOUGH SO ONLY A
FEW LIGHT RAIN SHOWERS ARE ABLE TO REACH THE SURFACE. THIS PATTERN
WILL PREVAIL THROUGH MIDWEEK...THEN A STRONGER FRONT WILL BRING A
MORE SOLID SHOT OF RAIN TO THE AREA THURSDAY NIGHT. LOWERING SNOW
LEVELS SHOULD BRING SOME ACCUMULATING SNOW TO THE CASCADES FRIDAY AND
SATURDAY. HOWEVER...RISING SNOW LEVELS AND SUBTROPICAL MOISTURE
SPILLING INTO THE REGION WILL LIKELY BRING RAIN TO ALL BUT THE
HIGHEST PEAKS LATE IN THE WEEKEND AND EARLY NEXT WEEK.

&&

.EVENING UPDATE...VERY LITTLE IN THE WAY OF CHANGE TO THE AFTERNOON
FORECAST PACKAGE THIS EVENING...AS FORECAST APPEARS TO BE SOLIDLY ON
TRACK. RADAR SHOWS LITTLE IN THE WAY OF MOISTURE ASSOCIATED WITH THE
LATEST WEAK FRONTAL SYSTEM PIVOTING THROUGH WESTERN OREGON.
ASSOCIATED FORCING IS WEAK WITH ONLY WEAK LOW TO MID-LEVEL
FRONTOGENESIS AND MEAGER JET DYNAMICS. THUS WE EXPECT ONLY A FEW
PERIODS OF LIGHT RAIN...OR POSSIBLY JUST SPRINKLES IN SOME AREAS AS
THE AIR MASS HAS BEEN DRIED OUT BY LOW-LEVEL OFFSHORE FLOW.
TEMPERATURES HAVE LOWERED TO 32-35 DEG F IN THE UPPER PORTIONS OF THE
HOOD RIVER VALLEY...WHERE SOME LIGHT SNOW ACCUMULATIONS UP TO AN INCH
OR SO ARE POSSIBLE THROUGH TUESDAY MORNING.

KTTD-KDLS GRADIENTS HAVE DECREASED IN MAGNITUDE...-5.8 MB AS OPPOSED
TO THE -7.2 MB WHICH RESULTED IN LAST NIGHTS GUSTY EASTERLY FLOW.
GRADIENTS SHOULD CONTINUE TO SLOWLY SLACKEN OVER THE NEXT COUPLE
DAYS...AS HIGH PRESSURE SLOWLY WEAKENS EAST OF THE CASCADES. THERE
COULD BE BRIEF VARIATIONS IN THIS TREND...BUT OVERALL EXPECT EAST
WINDS TO BE SLOWLY RAMPING DOWN THE NEXT COUPLE DAYS. EAST WINDS MAY
PICK UP AGAIN THROUGH THE GORGE THU/THU NIGHT AS A STRONGER PACIFIC
FRONTAL SYSTEM APPROACHES THE COAST. THIS SYSTEM WILL BRING A BETTER
SHOT OF RAIN AND GUSTY SOUTH WINDS ALONG THE COAST AS WELL.  WEAGLE

.SHORT TERM...TONIGHT THROUGH THURSDAY...A COMPOSITE OF SATELLITE AND
RADAR IMAGERY SHOWS AN ELONGATED UPPER LEVEL TROUGH SLOWLY SLIDING
EASTWARD INTO THE PACIFIC NORTHWEST. OFF AND ON LIGHT RAIN HAS BEEN
OBSERVED ALONG THE COAST AND ACROSS THE SOUTHERN HALF OF THE
WILLAMETTE VALLEY TODAY. HOWEVER...QPF HAS BEEN MEAGER THUS FAR.
EXPECT THIS TREND TO CONTINUE...BUT AS THE UPPER LEVEL TROUGH AXIS
NUDGES EASTWARD...EXPECT LIGHT RAIN TO INCREASE ACROSS THE REST OF
NORTHWEST OREGON AND SOUTHWEST WASHINGTON OVERNIGHT AS THE LOWER
ATMOSPHERE MOISTENS A BIT.

THE NAM CONTINUES TO SUGGEST HEAVIER QPF WILL FALL ACROSS THE CENTRAL
COLUMBIA RIVER GORGE AND UPPER HOOD RIVER VALLEY OVERNIGHT...LIKELY
DUE TO A COMBINATION OF A WARM ADVECTION ALOFT AND LOW LEVEL UPSLOPE
FLOW INTO THE EAST SLOPES OF THE CASCADES. HOWEVER...AFTER
INVESTIGATING THE SREF ENSEMBLE MEMBERS...THE OPERATIONAL NAM IS THE
OUTLIER IN TERMS OF QPF VALUES FOR KDLS. AS A RESULT...QPF VALUES
WERE TRENDED TOWARDS THE SREF MEAN FOR THE CENTRAL COLUMBIA RIVER
GORGE AND UPPER HOOD RIVER VALLEY. GIVEN THE LOW LEVEL STRATUS IN
PLACE ACROSS THE COLUMBIA RIVER BASIN...DO NOT EXPECT TEMPERATURES
TO DROP DRAMATICALLY OVERNIGHT FROM THEIR CURRENT READINGS AROUND
HOOD RIVER AND PARKDALE. AS A RESULT...ANY PRECIPITATION SHOULD FALL
AS EITHER A COLD RAIN OR A RAIN/SNOW MIX AROUND HOOD RIVER AND AS
WET SNOW IN THE UPPER HOOD RIVER VALLEY. THUS...AN INCH OR TWO OF
SNOW APPEARS POSSIBLE ABOVE 1000 TO 1500 FT TONIGHT AROUND THE
CENTRAL COLUMBIA RIVER GORGE...BUT SUSPECT AMOUNTS APPROACHING THESE
NUMBERS COULD BE HARD TO COME BY EVEN IN THE UPPER HOOD RIVER VALLEY
BASED ON CURRENT TEMPERATURES AND MOST SREF QPF VALUES.

AN AREA OF ENHANCED CLOUD TOPS CURRENTLY NEAR 135W DUE WEST OF OREGON
WILL CONTINUE TO SPREAD EASTWARD TOWARDS THE COAST. MODELS ARE IN
REASONABLE AGREEMENT A SURFACE LOW PRESSURE WILL INTENSIFY OVERNIGHT
AND TUESDAY AS IT MOVES TOWARDS THE NORTHERN CALIFORNIA AND SOUTH
OREGON COAST. THIS SHOULD REINFORCE OFFSHORE LOW LEVEL FLOW AND TURN
OUR FLOW ALOFT A TOUCH MORE SOUTHERLY...WHICH SHOULD REDUCE SHOWER
ACTIVITY ON TUESDAY...PARTICULARLY DURING THE AFTERNOON AND EVENING
HOURS.

THE UPPER LEVEL TROUGH AXIS STILL LOOKS TO SWING THROUGH LATE
TUESDAY NIGHT INTO WEDNESDAY...PROBABLY BRINGING AN UPTICK IN SHOWER
ACTIVITY DURING THIS PERIOD. NOT ALL MODELS ARE ON BOARD WITH THIS
SCENARIO SO POPS WERE STILL KEPT IN THE HIGH END CHANCE TO LOW END
LIKELY RANGE FOR THIS TIME PERIOD...BUT SYNOPTICALLY THIS IDEA SEEMS
REASONABLE.

EVEN THOUGH SHORTWAVE RIDGING WILL BE PUSHING INTO THE REGION LATE
WEDNESDAY INTO EARLY THURSDAY...THE EC/SREF SUGGEST A WARM FRONT AND
LIGHT RAIN WILL PUSH INTO THE REGION ON THURSDAY...REDUCING THE
LENGTH OF OUR DRY WEATHER WINDOW. GIVEN THE GFS AND NAM KEEP US
RELATIVELY DRY DURING THIS PERIOD...POPS WERE HELD MAINLY IN THE
CHANCE RANGE FOR NOW ON THURSDAY. /NEUMAN


.LONG TERM...THURSDAY NIGHT THROUGH MONDAY...MODELS ARE IN GOOD
AGREEMENT A RELATIVELY STRONG FRONT WILL BRING A SOLID SHOT OF RAIN
TO THE AREA THURSDAY NIGHT INTO EARLY FRIDAY. FORTUNATELY...THIS WILL
BE FAIRLY TRANSIENT STORM SYSTEM SO HYDRO CONCERNS ARE LOW.

A COLD AIR UNSTABLE AIRMASS WILL FOLLOW AND KEEP SHOWERS GOING INTO
FRIDAY. SNOW LEVELS SHOULD LOWER TO NEAR 4000 FT ON FRIDAY SO
ACCUMULATING SNOW APPEARS LIKELY FOR AT LEAST THE HIGHER PASSES. AN
ADDITIONAL SHORTWAVE TROUGH OR TWO COULD ENHANCE SHOWER ACTIVITY
EARLY IN THE WEEKEND AND BRING MUCH NEEDED SNOW TO THE HIGHER
CASCADES.

MODELS GENERALLY AGREE SNOW LEVELS WILL RISE LATE IN THE WEEKEND AS A
WARM FRONT SLIDES INTO THE REGION. STRONG ZONAL FLOW WILL FOCUS
PERSISTENT AND HEAVIER RAIN ACROSS SOUTHWEST BRITISH COLUMBIA AND
WESTERN WASHINGTON LATE IN THE WEEKEND AND EARLY NEXT WEEK. FOR
NOW...IT APPEARS THE BULK OF THE HEAVIEST RAIN WILL REMAIN NORTH OF
OUR REGION...AND WHEN HEAVIER PRECIPITATION ARRIVES...IT WILL REMAIN
TRANSIENT ENOUGH ACROSS OUR FORECAST AREA TO MINIMIZE FLOOD
CONCERNS. NONETHELESS...THIS PATTERN CERTAINLY BEARS
WATCHING...PARTICULARLY ACROSS THE NORTHERN HALF OF THE FORECAST
AREA WHERE A SLIGHT SHIFT IN THE STORM TRACK COULD PUT US IN THE
PATH OF A MODEST FIRE HOSE AND FLOOD CONCERNS WILL RISE. /NEUMAN


&&


.AVIATION...VFR WITH INCREASING MID LEVEL CLOUDS THIS EVENING. A
WEAK FRONT OFF THE COAST WILL PUSH MVFR CIGS AGAINST THE COAST
THIS EVENING...AND POSSIBLY INTO THE INTERIOR AFTER 09Z. BEST
THREAT OF INLAND MVFR WILL BE S OF A KHIO TO KUAO LINE. NOT MUCH
CHANGE THROUGH DAY ON TUE...WITH PLENTY OF LOW TO MID VFR
CLOUDS...WITH AREAS OF MVFR CIGS THROUGH 18Z.

KPDX AND APPROACHES...VFR TONIGHT WITH CIGS LOWERING FROM 7K TO
NEAR 4K BY LATE TONIGHT. LIGHT TO MODERATE E WINDS CONTINUE
TONIGHT THEN EASE A BIT AFTER 15Z TUE.ROCKEY.

&&

.MARINE...A SERIES OF WEAK SYSTEMS WILL AFFECT THE WATERS FOR THE
NEXT SEVERAL DAYS. AS FIRST FRONT MOVES INTO THE REGION...WILL
HAVE SOUTH GUSTS 20 TO 25 KT TONIGHT ACROSS OUTER WATERS...THEN
WINDS EASE TUE AM.

SEAS GENERALLY 13 TO 16 FT THIS EVENING. WILL SEE A VERY VERY
SLOW DECREASE IN SEAS LATER TONIGHT INTO TUE AM...WITH SEAS 10 TO
12 TUE AM INTO EARLY TUE AFTERNOON. STILL THINK SEAS DROP BACK
UNDER 10 FT LATE TUE AFTERNOON OR EARLY EVENING.

NEXT ORGANIZED FRONT ARRIVES LATE THU INTO FRI. STRONG POTENTIAL
FOR GALE FORCE SOUTHERLY WINDS AT THAT TIME...WITH SEAS GETTING
BACK UP INTO THE 15 TO 20 FT RANGE.      ROCKEY.

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL NOON TUESDAY FOR THE
       OUTER WATERS...OR FROM CAPE SHOALWATER TO FLORENCE AND
       FROM 10 TO 60 MILES OFFSHORE.
    SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 PM TUE
       ON ALL WATERS.
    SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR TONIGHT
       AND AGAIN FROM 10 AM TO 2 PM TUE.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.



000
FXUS66 KPQR 160439
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
838 PM PST MON DEC 15 2014

.SYNOPSIS...A SERIES OF WEAK FRONTAL SYSTEMS CONTINUES TO MOVE
ONSHORE...WITH THE LATEST PIVOTING THROUGH WESTERN OREGON THIS
EVENING. HIGH PRESSURE REMAINS EAST OF THE CASCADES...PRODUCING
LOW-LEVEL OFFSHORE FLOW AND KEEPING THE AIR MASS DRY ENOUGH SO ONLY A
FEW LIGHT RAIN SHOWERS ARE ABLE TO REACH THE SURFACE. THIS PATTERN
WILL PREVAIL THROUGH MIDWEEK...THEN A STRONGER FRONT WILL BRING A
MORE SOLID SHOT OF RAIN TO THE AREA THURSDAY NIGHT. LOWERING SNOW
LEVELS SHOULD BRING SOME ACCUMULATING SNOW TO THE CASCADES FRIDAY AND
SATURDAY. HOWEVER...RISING SNOW LEVELS AND SUBTROPICAL MOISTURE
SPILLING INTO THE REGION WILL LIKELY BRING RAIN TO ALL BUT THE
HIGHEST PEAKS LATE IN THE WEEKEND AND EARLY NEXT WEEK.

&&

.EVENING UPDATE...VERY LITTLE IN THE WAY OF CHANGE TO THE AFTERNOON
FORECAST PACKAGE THIS EVENING...AS FORECAST APPEARS TO BE SOLIDLY ON
TRACK. RADAR SHOWS LITTLE IN THE WAY OF MOISTURE ASSOCIATED WITH THE
LATEST WEAK FRONTAL SYSTEM PIVOTING THROUGH WESTERN OREGON.
ASSOCIATED FORCING IS WEAK WITH ONLY WEAK LOW TO MID-LEVEL
FRONTOGENESIS AND MEAGER JET DYNAMICS. THUS WE EXPECT ONLY A FEW
PERIODS OF LIGHT RAIN...OR POSSIBLY JUST SPRINKLES IN SOME AREAS AS
THE AIR MASS HAS BEEN DRIED OUT BY LOW-LEVEL OFFSHORE FLOW.
TEMPERATURES HAVE LOWERED TO 32-35 DEG F IN THE UPPER PORTIONS OF THE
HOOD RIVER VALLEY...WHERE SOME LIGHT SNOW ACCUMULATIONS UP TO AN INCH
OR SO ARE POSSIBLE THROUGH TUESDAY MORNING.

KTTD-KDLS GRADIENTS HAVE DECREASED IN MAGNITUDE...-5.8 MB AS OPPOSED
TO THE -7.2 MB WHICH RESULTED IN LAST NIGHTS GUSTY EASTERLY FLOW.
GRADIENTS SHOULD CONTINUE TO SLOWLY SLACKEN OVER THE NEXT COUPLE
DAYS...AS HIGH PRESSURE SLOWLY WEAKENS EAST OF THE CASCADES. THERE
COULD BE BRIEF VARIATIONS IN THIS TREND...BUT OVERALL EXPECT EAST
WINDS TO BE SLOWLY RAMPING DOWN THE NEXT COUPLE DAYS. EAST WINDS MAY
PICK UP AGAIN THROUGH THE GORGE THU/THU NIGHT AS A STRONGER PACIFIC
FRONTAL SYSTEM APPROACHES THE COAST. THIS SYSTEM WILL BRING A BETTER
SHOT OF RAIN AND GUSTY SOUTH WINDS ALONG THE COAST AS WELL.  WEAGLE

.SHORT TERM...TONIGHT THROUGH THURSDAY...A COMPOSITE OF SATELLITE AND
RADAR IMAGERY SHOWS AN ELONGATED UPPER LEVEL TROUGH SLOWLY SLIDING
EASTWARD INTO THE PACIFIC NORTHWEST. OFF AND ON LIGHT RAIN HAS BEEN
OBSERVED ALONG THE COAST AND ACROSS THE SOUTHERN HALF OF THE
WILLAMETTE VALLEY TODAY. HOWEVER...QPF HAS BEEN MEAGER THUS FAR.
EXPECT THIS TREND TO CONTINUE...BUT AS THE UPPER LEVEL TROUGH AXIS
NUDGES EASTWARD...EXPECT LIGHT RAIN TO INCREASE ACROSS THE REST OF
NORTHWEST OREGON AND SOUTHWEST WASHINGTON OVERNIGHT AS THE LOWER
ATMOSPHERE MOISTENS A BIT.

THE NAM CONTINUES TO SUGGEST HEAVIER QPF WILL FALL ACROSS THE CENTRAL
COLUMBIA RIVER GORGE AND UPPER HOOD RIVER VALLEY OVERNIGHT...LIKELY
DUE TO A COMBINATION OF A WARM ADVECTION ALOFT AND LOW LEVEL UPSLOPE
FLOW INTO THE EAST SLOPES OF THE CASCADES. HOWEVER...AFTER
INVESTIGATING THE SREF ENSEMBLE MEMBERS...THE OPERATIONAL NAM IS THE
OUTLIER IN TERMS OF QPF VALUES FOR KDLS. AS A RESULT...QPF VALUES
WERE TRENDED TOWARDS THE SREF MEAN FOR THE CENTRAL COLUMBIA RIVER
GORGE AND UPPER HOOD RIVER VALLEY. GIVEN THE LOW LEVEL STRATUS IN
PLACE ACROSS THE COLUMBIA RIVER BASIN...DO NOT EXPECT TEMPERATURES
TO DROP DRAMATICALLY OVERNIGHT FROM THEIR CURRENT READINGS AROUND
HOOD RIVER AND PARKDALE. AS A RESULT...ANY PRECIPITATION SHOULD FALL
AS EITHER A COLD RAIN OR A RAIN/SNOW MIX AROUND HOOD RIVER AND AS
WET SNOW IN THE UPPER HOOD RIVER VALLEY. THUS...AN INCH OR TWO OF
SNOW APPEARS POSSIBLE ABOVE 1000 TO 1500 FT TONIGHT AROUND THE
CENTRAL COLUMBIA RIVER GORGE...BUT SUSPECT AMOUNTS APPROACHING THESE
NUMBERS COULD BE HARD TO COME BY EVEN IN THE UPPER HOOD RIVER VALLEY
BASED ON CURRENT TEMPERATURES AND MOST SREF QPF VALUES.

AN AREA OF ENHANCED CLOUD TOPS CURRENTLY NEAR 135W DUE WEST OF OREGON
WILL CONTINUE TO SPREAD EASTWARD TOWARDS THE COAST. MODELS ARE IN
REASONABLE AGREEMENT A SURFACE LOW PRESSURE WILL INTENSIFY OVERNIGHT
AND TUESDAY AS IT MOVES TOWARDS THE NORTHERN CALIFORNIA AND SOUTH
OREGON COAST. THIS SHOULD REINFORCE OFFSHORE LOW LEVEL FLOW AND TURN
OUR FLOW ALOFT A TOUCH MORE SOUTHERLY...WHICH SHOULD REDUCE SHOWER
ACTIVITY ON TUESDAY...PARTICULARLY DURING THE AFTERNOON AND EVENING
HOURS.

THE UPPER LEVEL TROUGH AXIS STILL LOOKS TO SWING THROUGH LATE
TUESDAY NIGHT INTO WEDNESDAY...PROBABLY BRINGING AN UPTICK IN SHOWER
ACTIVITY DURING THIS PERIOD. NOT ALL MODELS ARE ON BOARD WITH THIS
SCENARIO SO POPS WERE STILL KEPT IN THE HIGH END CHANCE TO LOW END
LIKELY RANGE FOR THIS TIME PERIOD...BUT SYNOPTICALLY THIS IDEA SEEMS
REASONABLE.

EVEN THOUGH SHORTWAVE RIDGING WILL BE PUSHING INTO THE REGION LATE
WEDNESDAY INTO EARLY THURSDAY...THE EC/SREF SUGGEST A WARM FRONT AND
LIGHT RAIN WILL PUSH INTO THE REGION ON THURSDAY...REDUCING THE
LENGTH OF OUR DRY WEATHER WINDOW. GIVEN THE GFS AND NAM KEEP US
RELATIVELY DRY DURING THIS PERIOD...POPS WERE HELD MAINLY IN THE
CHANCE RANGE FOR NOW ON THURSDAY. /NEUMAN


.LONG TERM...THURSDAY NIGHT THROUGH MONDAY...MODELS ARE IN GOOD
AGREEMENT A RELATIVELY STRONG FRONT WILL BRING A SOLID SHOT OF RAIN
TO THE AREA THURSDAY NIGHT INTO EARLY FRIDAY. FORTUNATELY...THIS WILL
BE FAIRLY TRANSIENT STORM SYSTEM SO HYDRO CONCERNS ARE LOW.

A COLD AIR UNSTABLE AIRMASS WILL FOLLOW AND KEEP SHOWERS GOING INTO
FRIDAY. SNOW LEVELS SHOULD LOWER TO NEAR 4000 FT ON FRIDAY SO
ACCUMULATING SNOW APPEARS LIKELY FOR AT LEAST THE HIGHER PASSES. AN
ADDITIONAL SHORTWAVE TROUGH OR TWO COULD ENHANCE SHOWER ACTIVITY
EARLY IN THE WEEKEND AND BRING MUCH NEEDED SNOW TO THE HIGHER
CASCADES.

MODELS GENERALLY AGREE SNOW LEVELS WILL RISE LATE IN THE WEEKEND AS A
WARM FRONT SLIDES INTO THE REGION. STRONG ZONAL FLOW WILL FOCUS
PERSISTENT AND HEAVIER RAIN ACROSS SOUTHWEST BRITISH COLUMBIA AND
WESTERN WASHINGTON LATE IN THE WEEKEND AND EARLY NEXT WEEK. FOR
NOW...IT APPEARS THE BULK OF THE HEAVIEST RAIN WILL REMAIN NORTH OF
OUR REGION...AND WHEN HEAVIER PRECIPITATION ARRIVES...IT WILL REMAIN
TRANSIENT ENOUGH ACROSS OUR FORECAST AREA TO MINIMIZE FLOOD
CONCERNS. NONETHELESS...THIS PATTERN CERTAINLY BEARS
WATCHING...PARTICULARLY ACROSS THE NORTHERN HALF OF THE FORECAST
AREA WHERE A SLIGHT SHIFT IN THE STORM TRACK COULD PUT US IN THE
PATH OF A MODEST FIRE HOSE AND FLOOD CONCERNS WILL RISE. /NEUMAN


&&


.AVIATION...VFR WITH INCREASING MID LEVEL CLOUDS THIS EVENING. A
WEAK FRONT OFF THE COAST WILL PUSH MVFR CIGS AGAINST THE COAST
THIS EVENING...AND POSSIBLY INTO THE INTERIOR AFTER 09Z. BEST
THREAT OF INLAND MVFR WILL BE S OF A KHIO TO KUAO LINE. NOT MUCH
CHANGE THROUGH DAY ON TUE...WITH PLENTY OF LOW TO MID VFR
CLOUDS...WITH AREAS OF MVFR CIGS THROUGH 18Z.

KPDX AND APPROACHES...VFR TONIGHT WITH CIGS LOWERING FROM 7K TO
NEAR 4K BY LATE TONIGHT. LIGHT TO MODERATE E WINDS CONTINUE
TONIGHT THEN EASE A BIT AFTER 15Z TUE.ROCKEY.

&&

.MARINE...A SERIES OF WEAK SYSTEMS WILL AFFECT THE WATERS FOR THE
NEXT SEVERAL DAYS. AS FIRST FRONT MOVES INTO THE REGION...WILL
HAVE SOUTH GUSTS 20 TO 25 KT TONIGHT ACROSS OUTER WATERS...THEN
WINDS EASE TUE AM.

SEAS GENERALLY 13 TO 16 FT THIS EVENING. WILL SEE A VERY VERY
SLOW DECREASE IN SEAS LATER TONIGHT INTO TUE AM...WITH SEAS 10 TO
12 TUE AM INTO EARLY TUE AFTERNOON. STILL THINK SEAS DROP BACK
UNDER 10 FT LATE TUE AFTERNOON OR EARLY EVENING.

NEXT ORGANIZED FRONT ARRIVES LATE THU INTO FRI. STRONG POTENTIAL
FOR GALE FORCE SOUTHERLY WINDS AT THAT TIME...WITH SEAS GETTING
BACK UP INTO THE 15 TO 20 FT RANGE.      ROCKEY.

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL NOON TUESDAY FOR THE
       OUTER WATERS...OR FROM CAPE SHOALWATER TO FLORENCE AND
       FROM 10 TO 60 MILES OFFSHORE.
    SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 PM TUE
       ON ALL WATERS.
    SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR TONIGHT
       AND AGAIN FROM 10 AM TO 2 PM TUE.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.




000
FXUS66 KPQR 160439
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
838 PM PST MON DEC 15 2014

.SYNOPSIS...A SERIES OF WEAK FRONTAL SYSTEMS CONTINUES TO MOVE
ONSHORE...WITH THE LATEST PIVOTING THROUGH WESTERN OREGON THIS
EVENING. HIGH PRESSURE REMAINS EAST OF THE CASCADES...PRODUCING
LOW-LEVEL OFFSHORE FLOW AND KEEPING THE AIR MASS DRY ENOUGH SO ONLY A
FEW LIGHT RAIN SHOWERS ARE ABLE TO REACH THE SURFACE. THIS PATTERN
WILL PREVAIL THROUGH MIDWEEK...THEN A STRONGER FRONT WILL BRING A
MORE SOLID SHOT OF RAIN TO THE AREA THURSDAY NIGHT. LOWERING SNOW
LEVELS SHOULD BRING SOME ACCUMULATING SNOW TO THE CASCADES FRIDAY AND
SATURDAY. HOWEVER...RISING SNOW LEVELS AND SUBTROPICAL MOISTURE
SPILLING INTO THE REGION WILL LIKELY BRING RAIN TO ALL BUT THE
HIGHEST PEAKS LATE IN THE WEEKEND AND EARLY NEXT WEEK.

&&

.EVENING UPDATE...VERY LITTLE IN THE WAY OF CHANGE TO THE AFTERNOON
FORECAST PACKAGE THIS EVENING...AS FORECAST APPEARS TO BE SOLIDLY ON
TRACK. RADAR SHOWS LITTLE IN THE WAY OF MOISTURE ASSOCIATED WITH THE
LATEST WEAK FRONTAL SYSTEM PIVOTING THROUGH WESTERN OREGON.
ASSOCIATED FORCING IS WEAK WITH ONLY WEAK LOW TO MID-LEVEL
FRONTOGENESIS AND MEAGER JET DYNAMICS. THUS WE EXPECT ONLY A FEW
PERIODS OF LIGHT RAIN...OR POSSIBLY JUST SPRINKLES IN SOME AREAS AS
THE AIR MASS HAS BEEN DRIED OUT BY LOW-LEVEL OFFSHORE FLOW.
TEMPERATURES HAVE LOWERED TO 32-35 DEG F IN THE UPPER PORTIONS OF THE
HOOD RIVER VALLEY...WHERE SOME LIGHT SNOW ACCUMULATIONS UP TO AN INCH
OR SO ARE POSSIBLE THROUGH TUESDAY MORNING.

KTTD-KDLS GRADIENTS HAVE DECREASED IN MAGNITUDE...-5.8 MB AS OPPOSED
TO THE -7.2 MB WHICH RESULTED IN LAST NIGHTS GUSTY EASTERLY FLOW.
GRADIENTS SHOULD CONTINUE TO SLOWLY SLACKEN OVER THE NEXT COUPLE
DAYS...AS HIGH PRESSURE SLOWLY WEAKENS EAST OF THE CASCADES. THERE
COULD BE BRIEF VARIATIONS IN THIS TREND...BUT OVERALL EXPECT EAST
WINDS TO BE SLOWLY RAMPING DOWN THE NEXT COUPLE DAYS. EAST WINDS MAY
PICK UP AGAIN THROUGH THE GORGE THU/THU NIGHT AS A STRONGER PACIFIC
FRONTAL SYSTEM APPROACHES THE COAST. THIS SYSTEM WILL BRING A BETTER
SHOT OF RAIN AND GUSTY SOUTH WINDS ALONG THE COAST AS WELL.  WEAGLE

.SHORT TERM...TONIGHT THROUGH THURSDAY...A COMPOSITE OF SATELLITE AND
RADAR IMAGERY SHOWS AN ELONGATED UPPER LEVEL TROUGH SLOWLY SLIDING
EASTWARD INTO THE PACIFIC NORTHWEST. OFF AND ON LIGHT RAIN HAS BEEN
OBSERVED ALONG THE COAST AND ACROSS THE SOUTHERN HALF OF THE
WILLAMETTE VALLEY TODAY. HOWEVER...QPF HAS BEEN MEAGER THUS FAR.
EXPECT THIS TREND TO CONTINUE...BUT AS THE UPPER LEVEL TROUGH AXIS
NUDGES EASTWARD...EXPECT LIGHT RAIN TO INCREASE ACROSS THE REST OF
NORTHWEST OREGON AND SOUTHWEST WASHINGTON OVERNIGHT AS THE LOWER
ATMOSPHERE MOISTENS A BIT.

THE NAM CONTINUES TO SUGGEST HEAVIER QPF WILL FALL ACROSS THE CENTRAL
COLUMBIA RIVER GORGE AND UPPER HOOD RIVER VALLEY OVERNIGHT...LIKELY
DUE TO A COMBINATION OF A WARM ADVECTION ALOFT AND LOW LEVEL UPSLOPE
FLOW INTO THE EAST SLOPES OF THE CASCADES. HOWEVER...AFTER
INVESTIGATING THE SREF ENSEMBLE MEMBERS...THE OPERATIONAL NAM IS THE
OUTLIER IN TERMS OF QPF VALUES FOR KDLS. AS A RESULT...QPF VALUES
WERE TRENDED TOWARDS THE SREF MEAN FOR THE CENTRAL COLUMBIA RIVER
GORGE AND UPPER HOOD RIVER VALLEY. GIVEN THE LOW LEVEL STRATUS IN
PLACE ACROSS THE COLUMBIA RIVER BASIN...DO NOT EXPECT TEMPERATURES
TO DROP DRAMATICALLY OVERNIGHT FROM THEIR CURRENT READINGS AROUND
HOOD RIVER AND PARKDALE. AS A RESULT...ANY PRECIPITATION SHOULD FALL
AS EITHER A COLD RAIN OR A RAIN/SNOW MIX AROUND HOOD RIVER AND AS
WET SNOW IN THE UPPER HOOD RIVER VALLEY. THUS...AN INCH OR TWO OF
SNOW APPEARS POSSIBLE ABOVE 1000 TO 1500 FT TONIGHT AROUND THE
CENTRAL COLUMBIA RIVER GORGE...BUT SUSPECT AMOUNTS APPROACHING THESE
NUMBERS COULD BE HARD TO COME BY EVEN IN THE UPPER HOOD RIVER VALLEY
BASED ON CURRENT TEMPERATURES AND MOST SREF QPF VALUES.

AN AREA OF ENHANCED CLOUD TOPS CURRENTLY NEAR 135W DUE WEST OF OREGON
WILL CONTINUE TO SPREAD EASTWARD TOWARDS THE COAST. MODELS ARE IN
REASONABLE AGREEMENT A SURFACE LOW PRESSURE WILL INTENSIFY OVERNIGHT
AND TUESDAY AS IT MOVES TOWARDS THE NORTHERN CALIFORNIA AND SOUTH
OREGON COAST. THIS SHOULD REINFORCE OFFSHORE LOW LEVEL FLOW AND TURN
OUR FLOW ALOFT A TOUCH MORE SOUTHERLY...WHICH SHOULD REDUCE SHOWER
ACTIVITY ON TUESDAY...PARTICULARLY DURING THE AFTERNOON AND EVENING
HOURS.

THE UPPER LEVEL TROUGH AXIS STILL LOOKS TO SWING THROUGH LATE
TUESDAY NIGHT INTO WEDNESDAY...PROBABLY BRINGING AN UPTICK IN SHOWER
ACTIVITY DURING THIS PERIOD. NOT ALL MODELS ARE ON BOARD WITH THIS
SCENARIO SO POPS WERE STILL KEPT IN THE HIGH END CHANCE TO LOW END
LIKELY RANGE FOR THIS TIME PERIOD...BUT SYNOPTICALLY THIS IDEA SEEMS
REASONABLE.

EVEN THOUGH SHORTWAVE RIDGING WILL BE PUSHING INTO THE REGION LATE
WEDNESDAY INTO EARLY THURSDAY...THE EC/SREF SUGGEST A WARM FRONT AND
LIGHT RAIN WILL PUSH INTO THE REGION ON THURSDAY...REDUCING THE
LENGTH OF OUR DRY WEATHER WINDOW. GIVEN THE GFS AND NAM KEEP US
RELATIVELY DRY DURING THIS PERIOD...POPS WERE HELD MAINLY IN THE
CHANCE RANGE FOR NOW ON THURSDAY. /NEUMAN


.LONG TERM...THURSDAY NIGHT THROUGH MONDAY...MODELS ARE IN GOOD
AGREEMENT A RELATIVELY STRONG FRONT WILL BRING A SOLID SHOT OF RAIN
TO THE AREA THURSDAY NIGHT INTO EARLY FRIDAY. FORTUNATELY...THIS WILL
BE FAIRLY TRANSIENT STORM SYSTEM SO HYDRO CONCERNS ARE LOW.

A COLD AIR UNSTABLE AIRMASS WILL FOLLOW AND KEEP SHOWERS GOING INTO
FRIDAY. SNOW LEVELS SHOULD LOWER TO NEAR 4000 FT ON FRIDAY SO
ACCUMULATING SNOW APPEARS LIKELY FOR AT LEAST THE HIGHER PASSES. AN
ADDITIONAL SHORTWAVE TROUGH OR TWO COULD ENHANCE SHOWER ACTIVITY
EARLY IN THE WEEKEND AND BRING MUCH NEEDED SNOW TO THE HIGHER
CASCADES.

MODELS GENERALLY AGREE SNOW LEVELS WILL RISE LATE IN THE WEEKEND AS A
WARM FRONT SLIDES INTO THE REGION. STRONG ZONAL FLOW WILL FOCUS
PERSISTENT AND HEAVIER RAIN ACROSS SOUTHWEST BRITISH COLUMBIA AND
WESTERN WASHINGTON LATE IN THE WEEKEND AND EARLY NEXT WEEK. FOR
NOW...IT APPEARS THE BULK OF THE HEAVIEST RAIN WILL REMAIN NORTH OF
OUR REGION...AND WHEN HEAVIER PRECIPITATION ARRIVES...IT WILL REMAIN
TRANSIENT ENOUGH ACROSS OUR FORECAST AREA TO MINIMIZE FLOOD
CONCERNS. NONETHELESS...THIS PATTERN CERTAINLY BEARS
WATCHING...PARTICULARLY ACROSS THE NORTHERN HALF OF THE FORECAST
AREA WHERE A SLIGHT SHIFT IN THE STORM TRACK COULD PUT US IN THE
PATH OF A MODEST FIRE HOSE AND FLOOD CONCERNS WILL RISE. /NEUMAN


&&


.AVIATION...VFR WITH INCREASING MID LEVEL CLOUDS THIS EVENING. A
WEAK FRONT OFF THE COAST WILL PUSH MVFR CIGS AGAINST THE COAST
THIS EVENING...AND POSSIBLY INTO THE INTERIOR AFTER 09Z. BEST
THREAT OF INLAND MVFR WILL BE S OF A KHIO TO KUAO LINE. NOT MUCH
CHANGE THROUGH DAY ON TUE...WITH PLENTY OF LOW TO MID VFR
CLOUDS...WITH AREAS OF MVFR CIGS THROUGH 18Z.

KPDX AND APPROACHES...VFR TONIGHT WITH CIGS LOWERING FROM 7K TO
NEAR 4K BY LATE TONIGHT. LIGHT TO MODERATE E WINDS CONTINUE
TONIGHT THEN EASE A BIT AFTER 15Z TUE.ROCKEY.

&&

.MARINE...A SERIES OF WEAK SYSTEMS WILL AFFECT THE WATERS FOR THE
NEXT SEVERAL DAYS. AS FIRST FRONT MOVES INTO THE REGION...WILL
HAVE SOUTH GUSTS 20 TO 25 KT TONIGHT ACROSS OUTER WATERS...THEN
WINDS EASE TUE AM.

SEAS GENERALLY 13 TO 16 FT THIS EVENING. WILL SEE A VERY VERY
SLOW DECREASE IN SEAS LATER TONIGHT INTO TUE AM...WITH SEAS 10 TO
12 TUE AM INTO EARLY TUE AFTERNOON. STILL THINK SEAS DROP BACK
UNDER 10 FT LATE TUE AFTERNOON OR EARLY EVENING.

NEXT ORGANIZED FRONT ARRIVES LATE THU INTO FRI. STRONG POTENTIAL
FOR GALE FORCE SOUTHERLY WINDS AT THAT TIME...WITH SEAS GETTING
BACK UP INTO THE 15 TO 20 FT RANGE.      ROCKEY.

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL NOON TUESDAY FOR THE
       OUTER WATERS...OR FROM CAPE SHOALWATER TO FLORENCE AND
       FROM 10 TO 60 MILES OFFSHORE.
    SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 PM TUE
       ON ALL WATERS.
    SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR TONIGHT
       AND AGAIN FROM 10 AM TO 2 PM TUE.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.



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