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000
FXUS65 KTFX 200549
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1045 PM MST Fri Dec 19 2014

Updated Aviation

.UPDATE...Quick update to grids to add small areas of slight chance
of freezing rain after receiving reports of spotty light freezing
rain and mix of rain/snow in the Helena Valley and rain with a temp
of 26F at Ft Belknap. The main cell causing the Helena precip has
moved east of town, but there is still a small area of moisture to
the west heading toward town.  In the Ft Belknap area, the precip
band is moving steadily to the east-northeast, so any freezing rain
will be limited by the short duration of the precip over any given
site.
Waranauskas

&&

PREVIOUS UPDATE...(855 PM) Another night of quiet weather conditions
across central and southwest MT.  Latest satellite imagery shows the
shortwave trof that was in western MT this aftn has moved slightly
quicker than some forecast models were indicating.  The trof axis is
currently between Great Falls and Lewistown and making steady
progress eastward.  The moisture plume accompanying the trof has
been thinning as it moves along, as evidenced by very light and
spotty showers seen on latest radar imagery.  Even with the few
spots where radar echoes may be a bit better defined, it appears
that little if any precipitation is reaching the ground, especially
in the lower elevations.  Given the system`s quicker progress and
minimal precipitation coverage, main adjustment this evening was to
reduce the chances of precipitation by 20-30% over most of the
forecast area between now and 6am Saturday.  Rest of the current
forecast is in good shape.
Waranauskas

&&

.DISCUSSION...

Tonight through Sunday...
An upper level short wave trof and associated Pacific cold front
will move through the region overnight. This will case periods of
light snow across the Southwest. Warmer air in the southwest flow
ahead of this system could lift over a colder airmass in place
over eastern portions of north-central Montana. This creates a
possible light freezing rain scenario tonight. Have added freezing
rain to the forecast, but otherwise do not have enough confidence
to issue any advisories. Will continue to monitor once light
precipitation begins to spread through this area tonight.

Surface pressure falls are already causing wind gusts to pick up
at Deep Creek along the northern Rocky Mtn Front. Short term
guidance added confidence that wind gusts will briefly reach near
60 mph at isolated locations in this area early Saturday as the
front passes. Issued a high wind warning to cover this situation,
even knowing that gusts will taper Saturday. The high wind warning
continues on through Sunday as a much stronger downslope wind
signature appears with a strong lee trough and synoptic
subsidence. Issued a high wind watch extending east off the Rocky
Mountain front on Sunday to evaluate the possibility of a more
widespread high wind event Sunday.

An atmospheric river event is developing over the Pacific
Northwest Saturday night and Sunday. This affects mainly southwest
Montana...but heavy snow will accumulate along the Rocky
Mountains, shifting from north to south through Sunday. Snow
accumulations at pass level remain below 8 inches in 24 hours, so
issued a winter weather advisory for snow and blowing snow above
5000 feet. Downsloping winds and mild temperatures will keep any
snow accumulations within and closely adjacent to the Rocky
Mountain Front. In the southwest, snow accumulations could exceed
8 inches from 06Z Sunday through 06Z Monday. Snow levels are
forecast to rise above 5000 feet on Sunday, with rain possible in
the valleys. Will need to monitor forecast snowlevels before
upgrading to winter storm warning or dropping back to winter
weather advisory. Nutter

Sunday night through Friday...A rather active
weather pattern is setting up for much of the region for next
week. There will be several accumulating snowfall events that will
cause impacts for daily commuters and travelers. Through much of
the extended...the GFS13 and EC are in pretty good agreement.
Temperatures will be near/a bit above normal Monday and into
Tuesday...but then begin to turn colder Wednesday through Friday.
For now I used a blend of the colder models for temperatures...but
temperatures could be several degrees colder than currently
forecast should the snowpack become a bit deeper than expected.
Additionally...there is the potential for another high wind event
over portions of North Central MT on Tuesday.

In terms of precipitation...Southwest MT will continue to see
precipitation Sunday night and into Monday morning...with scattered
showers over North Central MT. The precipitation becomes
light and scattered Monday night through Tuesday. Then a another
fairly strong storm system will move through the region Wednesday
afternoon through Christmas Day. At this time...it looks like
Central and Southwest MT will see the brunt of this storm. At lower
elevations...there will be a swath of 3 to 5 inches of snow...with
around 8 to 10 inches in the mountains. It is too early to pin-point
the exact area that will see this heavier snowfall...but right now
that swath of heavier snow is forecast along a Helena to Bozeman
line. This line of heavier snow could shift a bit over the next few
days as later model runs get a better handle on the storm track.
Brusda/Blank

&&

.AVIATION...
UPDATED 0600Z.
Light mixed precipitation consisting of rain, freezing rain and snow
will affect KHLN and KHVR. Little to no ice accumulation is expected
at KHLN and KHVR and as temperatures warm above freezing tonight the
threat for freezing rain will diminish. At KBZN, temperatures are
cold enough that light snow showers may occur through 08z. Any snow
accumulation will be less than one-half inch. A surface cold front
associated with a weak upper-level weather system has quickly moved
across central Montana this evening. Winds have shifted southwest at
most TAF sites with gusts up to 15 kts. At KBZN, light and variable
winds will continue. While VFR conditions will be predominate, a
brief period of MVFR cigs/vis are possible in and near precipitation
at KBZN, KHVR and KHLN through 08z. Some fog is also possible at
KHLN, but confidence is low, thus have added VCFG to the TAF for
late tonight into Saturday morning. Mountains will also remain
obscured through Saturday morning. Conditions will improve after 12z
as a weak ridge of high pressure moves across the Treasure State.
Mid and high level clouds will begin to increase late Saturday
afternoon and evening as the next Pacific weather system approaches.
MLV

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  29  41  35  48 /  30   0  20  30
CTB  27  37  30  43 /  10   0  20  20
HLN  23  37  30  47 /  30  10  70  50
BZN  21  35  29  45 /  60  10  60  60
WEY  22  33  28  39 /  70  50  80  70
DLN  22  37  33  47 /  40  10  60  50
HVR  26  40  27  46 /  40  10  40  40
LWT  27  43  31  48 /  40  10  30  50

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY from 5 PM Saturday to 5 AM MST Monday
FOR ELEVATIONS ABOVE 5000 FEET FOR Central and Southern Lewis
and Clark...Jefferson...Northern Rocky Mountain Front...Southern
Rocky Mountain Front.

HIGH WIND WATCH from late Saturday night through Sunday
afternoon Eastern Glacier...Eastern Pondera...Eastern Teton...
Liberty...Toole.

HIGH WIND WARNING from 2 AM Saturday to 5 PM MST Sunday Northern
Rocky Mountain Front...Southern Rocky Mountain Front.

WINTER STORM WATCH from Saturday afternoon through late Sunday
night FOR ELEVATIONS ABOVE 6000 FEET FOR Beaverhead...Gallatin...
Madison.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls














000
FXUS65 KTFX 200549
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1045 PM MST Fri Dec 19 2014

Updated Aviation

.UPDATE...Quick update to grids to add small areas of slight chance
of freezing rain after receiving reports of spotty light freezing
rain and mix of rain/snow in the Helena Valley and rain with a temp
of 26F at Ft Belknap. The main cell causing the Helena precip has
moved east of town, but there is still a small area of moisture to
the west heading toward town.  In the Ft Belknap area, the precip
band is moving steadily to the east-northeast, so any freezing rain
will be limited by the short duration of the precip over any given
site.
Waranauskas

&&

PREVIOUS UPDATE...(855 PM) Another night of quiet weather conditions
across central and southwest MT.  Latest satellite imagery shows the
shortwave trof that was in western MT this aftn has moved slightly
quicker than some forecast models were indicating.  The trof axis is
currently between Great Falls and Lewistown and making steady
progress eastward.  The moisture plume accompanying the trof has
been thinning as it moves along, as evidenced by very light and
spotty showers seen on latest radar imagery.  Even with the few
spots where radar echoes may be a bit better defined, it appears
that little if any precipitation is reaching the ground, especially
in the lower elevations.  Given the system`s quicker progress and
minimal precipitation coverage, main adjustment this evening was to
reduce the chances of precipitation by 20-30% over most of the
forecast area between now and 6am Saturday.  Rest of the current
forecast is in good shape.
Waranauskas

&&

.DISCUSSION...

Tonight through Sunday...
An upper level short wave trof and associated Pacific cold front
will move through the region overnight. This will case periods of
light snow across the Southwest. Warmer air in the southwest flow
ahead of this system could lift over a colder airmass in place
over eastern portions of north-central Montana. This creates a
possible light freezing rain scenario tonight. Have added freezing
rain to the forecast, but otherwise do not have enough confidence
to issue any advisories. Will continue to monitor once light
precipitation begins to spread through this area tonight.

Surface pressure falls are already causing wind gusts to pick up
at Deep Creek along the northern Rocky Mtn Front. Short term
guidance added confidence that wind gusts will briefly reach near
60 mph at isolated locations in this area early Saturday as the
front passes. Issued a high wind warning to cover this situation,
even knowing that gusts will taper Saturday. The high wind warning
continues on through Sunday as a much stronger downslope wind
signature appears with a strong lee trough and synoptic
subsidence. Issued a high wind watch extending east off the Rocky
Mountain front on Sunday to evaluate the possibility of a more
widespread high wind event Sunday.

An atmospheric river event is developing over the Pacific
Northwest Saturday night and Sunday. This affects mainly southwest
Montana...but heavy snow will accumulate along the Rocky
Mountains, shifting from north to south through Sunday. Snow
accumulations at pass level remain below 8 inches in 24 hours, so
issued a winter weather advisory for snow and blowing snow above
5000 feet. Downsloping winds and mild temperatures will keep any
snow accumulations within and closely adjacent to the Rocky
Mountain Front. In the southwest, snow accumulations could exceed
8 inches from 06Z Sunday through 06Z Monday. Snow levels are
forecast to rise above 5000 feet on Sunday, with rain possible in
the valleys. Will need to monitor forecast snowlevels before
upgrading to winter storm warning or dropping back to winter
weather advisory. Nutter

Sunday night through Friday...A rather active
weather pattern is setting up for much of the region for next
week. There will be several accumulating snowfall events that will
cause impacts for daily commuters and travelers. Through much of
the extended...the GFS13 and EC are in pretty good agreement.
Temperatures will be near/a bit above normal Monday and into
Tuesday...but then begin to turn colder Wednesday through Friday.
For now I used a blend of the colder models for temperatures...but
temperatures could be several degrees colder than currently
forecast should the snowpack become a bit deeper than expected.
Additionally...there is the potential for another high wind event
over portions of North Central MT on Tuesday.

In terms of precipitation...Southwest MT will continue to see
precipitation Sunday night and into Monday morning...with scattered
showers over North Central MT. The precipitation becomes
light and scattered Monday night through Tuesday. Then a another
fairly strong storm system will move through the region Wednesday
afternoon through Christmas Day. At this time...it looks like
Central and Southwest MT will see the brunt of this storm. At lower
elevations...there will be a swath of 3 to 5 inches of snow...with
around 8 to 10 inches in the mountains. It is too early to pin-point
the exact area that will see this heavier snowfall...but right now
that swath of heavier snow is forecast along a Helena to Bozeman
line. This line of heavier snow could shift a bit over the next few
days as later model runs get a better handle on the storm track.
Brusda/Blank

&&

.AVIATION...
UPDATED 0600Z.
Light mixed precipitation consisting of rain, freezing rain and snow
will affect KHLN and KHVR. Little to no ice accumulation is expected
at KHLN and KHVR and as temperatures warm above freezing tonight the
threat for freezing rain will diminish. At KBZN, temperatures are
cold enough that light snow showers may occur through 08z. Any snow
accumulation will be less than one-half inch. A surface cold front
associated with a weak upper-level weather system has quickly moved
across central Montana this evening. Winds have shifted southwest at
most TAF sites with gusts up to 15 kts. At KBZN, light and variable
winds will continue. While VFR conditions will be predominate, a
brief period of MVFR cigs/vis are possible in and near precipitation
at KBZN, KHVR and KHLN through 08z. Some fog is also possible at
KHLN, but confidence is low, thus have added VCFG to the TAF for
late tonight into Saturday morning. Mountains will also remain
obscured through Saturday morning. Conditions will improve after 12z
as a weak ridge of high pressure moves across the Treasure State.
Mid and high level clouds will begin to increase late Saturday
afternoon and evening as the next Pacific weather system approaches.
MLV

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  29  41  35  48 /  30   0  20  30
CTB  27  37  30  43 /  10   0  20  20
HLN  23  37  30  47 /  30  10  70  50
BZN  21  35  29  45 /  60  10  60  60
WEY  22  33  28  39 /  70  50  80  70
DLN  22  37  33  47 /  40  10  60  50
HVR  26  40  27  46 /  40  10  40  40
LWT  27  43  31  48 /  40  10  30  50

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY from 5 PM Saturday to 5 AM MST Monday
FOR ELEVATIONS ABOVE 5000 FEET FOR Central and Southern Lewis
and Clark...Jefferson...Northern Rocky Mountain Front...Southern
Rocky Mountain Front.

HIGH WIND WATCH from late Saturday night through Sunday
afternoon Eastern Glacier...Eastern Pondera...Eastern Teton...
Liberty...Toole.

HIGH WIND WARNING from 2 AM Saturday to 5 PM MST Sunday Northern
Rocky Mountain Front...Southern Rocky Mountain Front.

WINTER STORM WATCH from Saturday afternoon through late Sunday
night FOR ELEVATIONS ABOVE 6000 FEET FOR Beaverhead...Gallatin...
Madison.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls















000
FXUS65 KTFX 200449
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
940 PM MST Fri Dec 19 2014

.UPDATE...Quick update to grids to add small areas of slight chance
of freezing rain after receiving reports of spotty light freezing
rain and mix of rain/snow in the Helena Valley and rain with a temp
of 26F at Ft Belknap. The main cell causing the Helena precip has
moved east of town, but there is still a small area of moisture to
the west heading toward town.  In the Ft Belknap area, the precip
band is moving steadily to the east-northeast, so any freezing rain
will be limited by the short duration of the precip over any given
site.
Waranauskas

&&

PREVIOUS UPDATE...(855 PM) Another night of quiet weather conditions
across central and southwest MT.  Latest satellite imagery shows the
shortwave trof that was in western MT this aftn has moved slightly
quicker than some forecast models were indicating.  The trof axis is
currently between Great Falls and Lewistown and making steady
progress eastward.  The moisture plume accompanying the trof has
been thinning as it moves along, as evidenced by very light and
spotty showers seen on latest radar imagery.  Even with the few
spots where radar echoes may be a bit better defined, it appears
that little if any precipitation is reaching the ground, especially
in the lower elevations.  Given the system`s quicker progress and
minimal precipitation coverage, main adjustment this evening was to
reduce the chances of precipitation by 20-30% over most of the
forecast area between now and 6am Saturday.  Rest of the current
forecast is in good shape.
Waranauskas

&&

.DISCUSSION...

Tonight through Sunday...
An upper level short wave trof and associated Pacific cold front
will move through the region overnight. This will case periods of
light snow across the Southwest. Warmer air in the southwest flow
ahead of this system could lift over a colder airmass in place
over eastern portions of north-central Montana. This creates a
possible light freezing rain scenario tonight. Have added freezing
rain to the forecast, but otherwise do not have enough confidence
to issue any advisories. Will continue to monitor once light
precipitation begins to spread through this area tonight.

Surface pressure falls are already causing wind gusts to pick up
at Deep Creek along the northern Rocky Mtn Front. Short term
guidance added confidence that wind gusts will briefly reach near
60 mph at isolated locations in this area early Saturday as the
front passes. Issued a high wind warning to cover this situation,
even knowing that gusts will taper Saturday. The high wind warning
continues on through Sunday as a much stronger downslope wind
signature appears with a strong lee trough and synoptic
subsidence. Issued a high wind watch extending east off the Rocky
Mountain front on Sunday to evaluate the possibility of a more
widespread high wind event Sunday.

An atmospheric river event is developing over the Pacific
Northwest Saturday night and Sunday. This affects mainly southwest
Montana...but heavy snow will accumulate along the Rocky
Mountains, shifting from north to south through Sunday. Snow
accumulations at pass level remain below 8 inches in 24 hours, so
issued a winter weather advisory for snow and blowing snow above
5000 feet. Downsloping winds and mild temperatures will keep any
snow accumulations within and closely adjacent to the Rocky
Mountain Front. In the southwest, snow accumulations could exceed
8 inches from 06Z Sunday through 06Z Monday. Snow levels are
forecast to rise above 5000 feet on Sunday, with rain possible in
the valleys. Will need to monitor forecast snowlevels before
upgrading to winter storm warning or dropping back to winter
weather advisory. Nutter

Sunday night through Friday...A rather active
weather pattern is setting up for much of the region for next
week. There will be several accumulating snowfall events that will
cause impacts for daily commuters and travelers. Through much of
the extended...the GFS13 and EC are in pretty good agreement.
Temperatures will be near/a bit above normal Monday and into
Tuesday...but then begin to turn colder Wednesday through Friday.
For now I used a blend of the colder models for temperatures...but
temperatures could be several degrees colder than currently
forecast should the snowpack become a bit deeper than expected.
Additionally...there is the potential for another high wind event
over portions of North Central MT on Tuesday.

In terms of precipitation...Southwest MT will continue to see
precipitation Sunday night and into Monday morning...with scattered
showers over North Central MT. The precipitation becomes
light and scattered Monday night through Tuesday. Then a another
fairly strong storm system will move through the region Wednesday
afternoon through Christmas Day. At this time...it looks like
Central and Southwest MT will see the brunt of this storm. At lower
elevations...there will be a swath of 3 to 5 inches of snow...with
around 8 to 10 inches in the mountains. It is too early to pin-point
the exact area that will see this heavier snowfall...but right now
that swath of heavier snow is forecast along a Helena to Bozeman
line. This line of heavier snow could shift a bit over the next few
days as later model runs get a better handle on the storm track.
Brusda/Blank

&&

.AVIATION...
UPDATED 0000Z.
A surface cold front associated with a weak upper-level weather
system will sweep from west to east through the forecast area this
evening. Conditions will deteriorate from west to east this evening
and tonight with mountains obscured in snow until late tonight. Have
moderate confidence in the timing of precipitation, but forecast
confidence is low for flight category cigs/vis. At KHVR, freezing
rain is possible late this evening, then should changeover to a
rain/snow mix. Rain and snow showers are expected at KGTF and KLWT
with light snow developing at KHLN and KBZN between 01z and 03z.
This is a fast-moving system with conditions improving by 12z
Saturday.

BZN TAF...as mentioned above have moderate confidence in the timing
of the threat of precipitation. Winds will remain light and variable
despite the cold frontal passage that is expected by 04z. Although
there is a prob group for MVFR conditions in snow from 03z to
07z..there could even be a brief period of IFR conditions in
steadier snow during this same time frame. Should these IFR
conditions develop they would last no more than an hour. Mountains
will become obscured later this evening and remain obscured through
Saturday morning. Blank/MLV

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  29  41  35  48 /  30   0  20  30
CTB  27  37  30  43 /  10   0  20  20
HLN  23  37  30  47 /  30  10  70  50
BZN  21  35  29  45 /  60  10  60  60
WEY  22  33  28  39 /  70  50  80  70
DLN  22  37  33  47 /  40  10  60  50
HVR  26  40  27  46 /  40  10  40  40
LWT  27  43  31  48 /  40  10  30  50

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY from 5 PM Saturday to 5 AM MST Monday
FOR ELEVATIONS ABOVE 5000 FEET FOR Central and Southern Lewis
and Clark...Jefferson...Northern Rocky Mountain Front...Southern
Rocky Mountain Front.

HIGH WIND WATCH from late Saturday night through Sunday
afternoon Eastern Glacier...Eastern Pondera...Eastern Teton...
Liberty...Toole.

HIGH WIND WARNING from 2 AM Saturday to 5 PM MST Sunday Northern
Rocky Mountain Front...Southern Rocky Mountain Front.

WINTER STORM WATCH from Saturday afternoon through late Sunday
night FOR ELEVATIONS ABOVE 6000 FEET FOR Beaverhead...Gallatin...
Madison.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls













000
FXUS65 KTFX 200449
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
940 PM MST Fri Dec 19 2014

.UPDATE...Quick update to grids to add small areas of slight chance
of freezing rain after receiving reports of spotty light freezing
rain and mix of rain/snow in the Helena Valley and rain with a temp
of 26F at Ft Belknap. The main cell causing the Helena precip has
moved east of town, but there is still a small area of moisture to
the west heading toward town.  In the Ft Belknap area, the precip
band is moving steadily to the east-northeast, so any freezing rain
will be limited by the short duration of the precip over any given
site.
Waranauskas

&&

PREVIOUS UPDATE...(855 PM) Another night of quiet weather conditions
across central and southwest MT.  Latest satellite imagery shows the
shortwave trof that was in western MT this aftn has moved slightly
quicker than some forecast models were indicating.  The trof axis is
currently between Great Falls and Lewistown and making steady
progress eastward.  The moisture plume accompanying the trof has
been thinning as it moves along, as evidenced by very light and
spotty showers seen on latest radar imagery.  Even with the few
spots where radar echoes may be a bit better defined, it appears
that little if any precipitation is reaching the ground, especially
in the lower elevations.  Given the system`s quicker progress and
minimal precipitation coverage, main adjustment this evening was to
reduce the chances of precipitation by 20-30% over most of the
forecast area between now and 6am Saturday.  Rest of the current
forecast is in good shape.
Waranauskas

&&

.DISCUSSION...

Tonight through Sunday...
An upper level short wave trof and associated Pacific cold front
will move through the region overnight. This will case periods of
light snow across the Southwest. Warmer air in the southwest flow
ahead of this system could lift over a colder airmass in place
over eastern portions of north-central Montana. This creates a
possible light freezing rain scenario tonight. Have added freezing
rain to the forecast, but otherwise do not have enough confidence
to issue any advisories. Will continue to monitor once light
precipitation begins to spread through this area tonight.

Surface pressure falls are already causing wind gusts to pick up
at Deep Creek along the northern Rocky Mtn Front. Short term
guidance added confidence that wind gusts will briefly reach near
60 mph at isolated locations in this area early Saturday as the
front passes. Issued a high wind warning to cover this situation,
even knowing that gusts will taper Saturday. The high wind warning
continues on through Sunday as a much stronger downslope wind
signature appears with a strong lee trough and synoptic
subsidence. Issued a high wind watch extending east off the Rocky
Mountain front on Sunday to evaluate the possibility of a more
widespread high wind event Sunday.

An atmospheric river event is developing over the Pacific
Northwest Saturday night and Sunday. This affects mainly southwest
Montana...but heavy snow will accumulate along the Rocky
Mountains, shifting from north to south through Sunday. Snow
accumulations at pass level remain below 8 inches in 24 hours, so
issued a winter weather advisory for snow and blowing snow above
5000 feet. Downsloping winds and mild temperatures will keep any
snow accumulations within and closely adjacent to the Rocky
Mountain Front. In the southwest, snow accumulations could exceed
8 inches from 06Z Sunday through 06Z Monday. Snow levels are
forecast to rise above 5000 feet on Sunday, with rain possible in
the valleys. Will need to monitor forecast snowlevels before
upgrading to winter storm warning or dropping back to winter
weather advisory. Nutter

Sunday night through Friday...A rather active
weather pattern is setting up for much of the region for next
week. There will be several accumulating snowfall events that will
cause impacts for daily commuters and travelers. Through much of
the extended...the GFS13 and EC are in pretty good agreement.
Temperatures will be near/a bit above normal Monday and into
Tuesday...but then begin to turn colder Wednesday through Friday.
For now I used a blend of the colder models for temperatures...but
temperatures could be several degrees colder than currently
forecast should the snowpack become a bit deeper than expected.
Additionally...there is the potential for another high wind event
over portions of North Central MT on Tuesday.

In terms of precipitation...Southwest MT will continue to see
precipitation Sunday night and into Monday morning...with scattered
showers over North Central MT. The precipitation becomes
light and scattered Monday night through Tuesday. Then a another
fairly strong storm system will move through the region Wednesday
afternoon through Christmas Day. At this time...it looks like
Central and Southwest MT will see the brunt of this storm. At lower
elevations...there will be a swath of 3 to 5 inches of snow...with
around 8 to 10 inches in the mountains. It is too early to pin-point
the exact area that will see this heavier snowfall...but right now
that swath of heavier snow is forecast along a Helena to Bozeman
line. This line of heavier snow could shift a bit over the next few
days as later model runs get a better handle on the storm track.
Brusda/Blank

&&

.AVIATION...
UPDATED 0000Z.
A surface cold front associated with a weak upper-level weather
system will sweep from west to east through the forecast area this
evening. Conditions will deteriorate from west to east this evening
and tonight with mountains obscured in snow until late tonight. Have
moderate confidence in the timing of precipitation, but forecast
confidence is low for flight category cigs/vis. At KHVR, freezing
rain is possible late this evening, then should changeover to a
rain/snow mix. Rain and snow showers are expected at KGTF and KLWT
with light snow developing at KHLN and KBZN between 01z and 03z.
This is a fast-moving system with conditions improving by 12z
Saturday.

BZN TAF...as mentioned above have moderate confidence in the timing
of the threat of precipitation. Winds will remain light and variable
despite the cold frontal passage that is expected by 04z. Although
there is a prob group for MVFR conditions in snow from 03z to
07z..there could even be a brief period of IFR conditions in
steadier snow during this same time frame. Should these IFR
conditions develop they would last no more than an hour. Mountains
will become obscured later this evening and remain obscured through
Saturday morning. Blank/MLV

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  29  41  35  48 /  30   0  20  30
CTB  27  37  30  43 /  10   0  20  20
HLN  23  37  30  47 /  30  10  70  50
BZN  21  35  29  45 /  60  10  60  60
WEY  22  33  28  39 /  70  50  80  70
DLN  22  37  33  47 /  40  10  60  50
HVR  26  40  27  46 /  40  10  40  40
LWT  27  43  31  48 /  40  10  30  50

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY from 5 PM Saturday to 5 AM MST Monday
FOR ELEVATIONS ABOVE 5000 FEET FOR Central and Southern Lewis
and Clark...Jefferson...Northern Rocky Mountain Front...Southern
Rocky Mountain Front.

HIGH WIND WATCH from late Saturday night through Sunday
afternoon Eastern Glacier...Eastern Pondera...Eastern Teton...
Liberty...Toole.

HIGH WIND WARNING from 2 AM Saturday to 5 PM MST Sunday Northern
Rocky Mountain Front...Southern Rocky Mountain Front.

WINTER STORM WATCH from Saturday afternoon through late Sunday
night FOR ELEVATIONS ABOVE 6000 FEET FOR Beaverhead...Gallatin...
Madison.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls












000
FXUS65 KTFX 200356
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
855 PM MST Fri Dec 19 2014

.UPDATE...
Another night of quiet weather conditions across central and
southwest MT.  Latest satellite imagery shows the shortwave trof
that was in western MT this aftn has moved slightly quicker than
some forecast models were indicating.  The trof axis is currently
between Great Falls and Lewistown and making steady progress
eastward.  The moisture plume accompanying the trof has been
thinning as it moves along, as evidenced by very light and spotty
showers seen on latest radar imagery.  Even with the few spots where
radar echoes may be a bit better defined, it appears that little if
any precipitation is reaching the ground, especially in the lower
elevations.  Given the system`s quicker progress and minimal
precipitation coverage, main adjustment this evening was to reduce
the chances of precipitation by 20-30% over most of the forecast
area between now and 6am Saturday.  Rest of the current forecast is
in good shape.
Waranauskas

&&

.DISCUSSION...

Tonight through Sunday...
An upper level short wave trof and associated Pacific cold front
will move through the region overnight. This will case periods of
light snow across the Southwest. Warmer air in the southwest flow
ahead of this system could lift over a colder airmass in place
over eastern portions of north-central Montana. This creates a
possible light freezing rain scenario tonight. Have added freezing
rain to the forecast, but otherwise do not have enough confidence
to issue any advisories. Will continue to monitor once light
precipitation begins to spread through this area tonight.

Surface pressure falls are already causing wind gusts to pick up
at Deep Creek along the northern Rocky Mtn Front. Short term
guidance added confidence that wind gusts will briefly reach near
60 mph at isolated locations in this area early Saturday as the
front passes. Issued a high wind warning to cover this situation,
even knowing that gusts will taper Saturday. The high wind warning
continues on through Sunday as a much stronger downslope wind
signature appears with a strong lee trough and synoptic
subsidence. Issued a high wind watch extending east off the Rocky
Mountain front on Sunday to evaluate the possibility of a more
widespread high wind event Sunday.

An atmospheric river event is developing over the Pacific
Northwest Saturday night and Sunday. This affects mainly southwest
Montana...but heavy snow will accumulate along the Rocky
Mountains, shifting from north to south through Sunday. Snow
accumulations at pass level remain below 8 inches in 24 hours, so
issued a winter weather advisory for snow and blowing snow above
5000 feet. Downsloping winds and mild temperatures will keep any
snow accumulations within and closely adjacent to the Rocky
Mountain Front. In the southwest, snow accumulations could exceed
8 inches from 06Z Sunday through 06Z Monday. Snow levels are
forecast to rise above 5000 feet on Sunday, with rain possible in
the valleys. Will need to monitor forecast snowlevels before
upgrading to winter storm warning or dropping back to winter
weather advisory. Nutter

Sunday night through Friday...A rather active
weather pattern is setting up for much of the region for next
week. There will be several accumulating snowfall events that will
cause impacts for daily commuters and travelers. Through much of
the extended...the GFS13 and EC are in pretty good agreement.
Temperatures will be near/a bit above normal Monday and into
Tuesday...but then begin to turn colder Wednesday through Friday.
For now I used a blend of the colder models for temperatures...but
temperatures could be several degrees colder than currently
forecast should the snowpack become a bit deeper than expected.
Additionally...there is the potential for another high wind event
over portions of North Central MT on Tuesday.

In terms of precipitation...Southwest MT will continue to see
precipitation Sunday night and into Monday morning...with scattered
showers over North Central MT. The precipitation becomes
light and scattered Monday night through Tuesday. Then a another
fairly strong storm system will move through the region Wednesday
afternoon through Christmas Day. At this time...it looks like
Central and Southwest MT will see the brunt of this storm. At lower
elevations...there will be a swath of 3 to 5 inches of snow...with
around 8 to 10 inches in the mountains. It is too early to pin-point
the exact area that will see this heavier snowfall...but right now
that swath of heavier snow is forecast along a Helena to Bozeman
line. This line of heavier snow could shift a bit over the next few
days as later model runs get a better handle on the storm track.
Brusda/Blank

&&

.AVIATION...
UPDATED 0000Z.
A surface cold front associated with a weak upper-level weather
system will sweep from west to east through the forecast area this
evening. Conditions will deteriorate from west to east this evening
and tonight with mountains obscured in snow until late tonight. Have
moderate confidence in the timing of precipitation, but forecast
confidence is low for flight category cigs/vis. At KHVR, freezing
rain is possible late this evening, then should changeover to a
rain/snow mix. Rain and snow showers are expected at KGTF and KLWT
with light snow developing at KHLN and KBZN between 01z and 03z.
This is a fast-moving system with conditions improving by 12z
Saturday.

BZN TAF...as mentioned above have moderate confidence in the timing
of the threat of precipitation. Winds will remain light and variable
despite the cold frontal passage that is expected by 04z. Although
there is a prob group for MVFR conditions in snow from 03z to
07z..there could even be a brief period of IFR conditions in
steadier snow during this same time frame. Should these IFR
conditions develop they would last no more than an hour. Mountains
will become obscured later this evening and remain obscured through
Saturday morning. Blank/MLV

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  29  41  35  48 /  30   0  20  30
CTB  27  37  30  43 /  10   0  20  20
HLN  23  37  30  47 /  30  10  70  50
BZN  21  35  29  45 /  60  10  60  60
WEY  22  33  28  39 /  70  50  80  70
DLN  22  37  33  47 /  40  10  60  50
HVR  26  40  27  46 /  40  10  40  40
LWT  27  43  31  48 /  40  10  30  50

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY from 5 PM Saturday to 5 AM MST Monday
FOR ELEVATIONS ABOVE 5000 FEET FOR Central and Southern Lewis
and Clark...Jefferson...Northern Rocky Mountain Front...Southern
Rocky Mountain Front.

HIGH WIND WATCH from late Saturday night through Sunday
afternoon Eastern Glacier...Eastern Pondera...Eastern Teton...
Liberty...Toole.

HIGH WIND WARNING from 2 AM Saturday to 5 PM MST Sunday Northern
Rocky Mountain Front...Southern Rocky Mountain Front.

WINTER STORM WATCH from Saturday afternoon through late Sunday
night FOR ELEVATIONS ABOVE 6000 FEET FOR Beaverhead...Gallatin...
Madison.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls











000
FXUS65 KTFX 200356
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
855 PM MST Fri Dec 19 2014

.UPDATE...
Another night of quiet weather conditions across central and
southwest MT.  Latest satellite imagery shows the shortwave trof
that was in western MT this aftn has moved slightly quicker than
some forecast models were indicating.  The trof axis is currently
between Great Falls and Lewistown and making steady progress
eastward.  The moisture plume accompanying the trof has been
thinning as it moves along, as evidenced by very light and spotty
showers seen on latest radar imagery.  Even with the few spots where
radar echoes may be a bit better defined, it appears that little if
any precipitation is reaching the ground, especially in the lower
elevations.  Given the system`s quicker progress and minimal
precipitation coverage, main adjustment this evening was to reduce
the chances of precipitation by 20-30% over most of the forecast
area between now and 6am Saturday.  Rest of the current forecast is
in good shape.
Waranauskas

&&

.DISCUSSION...

Tonight through Sunday...
An upper level short wave trof and associated Pacific cold front
will move through the region overnight. This will case periods of
light snow across the Southwest. Warmer air in the southwest flow
ahead of this system could lift over a colder airmass in place
over eastern portions of north-central Montana. This creates a
possible light freezing rain scenario tonight. Have added freezing
rain to the forecast, but otherwise do not have enough confidence
to issue any advisories. Will continue to monitor once light
precipitation begins to spread through this area tonight.

Surface pressure falls are already causing wind gusts to pick up
at Deep Creek along the northern Rocky Mtn Front. Short term
guidance added confidence that wind gusts will briefly reach near
60 mph at isolated locations in this area early Saturday as the
front passes. Issued a high wind warning to cover this situation,
even knowing that gusts will taper Saturday. The high wind warning
continues on through Sunday as a much stronger downslope wind
signature appears with a strong lee trough and synoptic
subsidence. Issued a high wind watch extending east off the Rocky
Mountain front on Sunday to evaluate the possibility of a more
widespread high wind event Sunday.

An atmospheric river event is developing over the Pacific
Northwest Saturday night and Sunday. This affects mainly southwest
Montana...but heavy snow will accumulate along the Rocky
Mountains, shifting from north to south through Sunday. Snow
accumulations at pass level remain below 8 inches in 24 hours, so
issued a winter weather advisory for snow and blowing snow above
5000 feet. Downsloping winds and mild temperatures will keep any
snow accumulations within and closely adjacent to the Rocky
Mountain Front. In the southwest, snow accumulations could exceed
8 inches from 06Z Sunday through 06Z Monday. Snow levels are
forecast to rise above 5000 feet on Sunday, with rain possible in
the valleys. Will need to monitor forecast snowlevels before
upgrading to winter storm warning or dropping back to winter
weather advisory. Nutter

Sunday night through Friday...A rather active
weather pattern is setting up for much of the region for next
week. There will be several accumulating snowfall events that will
cause impacts for daily commuters and travelers. Through much of
the extended...the GFS13 and EC are in pretty good agreement.
Temperatures will be near/a bit above normal Monday and into
Tuesday...but then begin to turn colder Wednesday through Friday.
For now I used a blend of the colder models for temperatures...but
temperatures could be several degrees colder than currently
forecast should the snowpack become a bit deeper than expected.
Additionally...there is the potential for another high wind event
over portions of North Central MT on Tuesday.

In terms of precipitation...Southwest MT will continue to see
precipitation Sunday night and into Monday morning...with scattered
showers over North Central MT. The precipitation becomes
light and scattered Monday night through Tuesday. Then a another
fairly strong storm system will move through the region Wednesday
afternoon through Christmas Day. At this time...it looks like
Central and Southwest MT will see the brunt of this storm. At lower
elevations...there will be a swath of 3 to 5 inches of snow...with
around 8 to 10 inches in the mountains. It is too early to pin-point
the exact area that will see this heavier snowfall...but right now
that swath of heavier snow is forecast along a Helena to Bozeman
line. This line of heavier snow could shift a bit over the next few
days as later model runs get a better handle on the storm track.
Brusda/Blank

&&

.AVIATION...
UPDATED 0000Z.
A surface cold front associated with a weak upper-level weather
system will sweep from west to east through the forecast area this
evening. Conditions will deteriorate from west to east this evening
and tonight with mountains obscured in snow until late tonight. Have
moderate confidence in the timing of precipitation, but forecast
confidence is low for flight category cigs/vis. At KHVR, freezing
rain is possible late this evening, then should changeover to a
rain/snow mix. Rain and snow showers are expected at KGTF and KLWT
with light snow developing at KHLN and KBZN between 01z and 03z.
This is a fast-moving system with conditions improving by 12z
Saturday.

BZN TAF...as mentioned above have moderate confidence in the timing
of the threat of precipitation. Winds will remain light and variable
despite the cold frontal passage that is expected by 04z. Although
there is a prob group for MVFR conditions in snow from 03z to
07z..there could even be a brief period of IFR conditions in
steadier snow during this same time frame. Should these IFR
conditions develop they would last no more than an hour. Mountains
will become obscured later this evening and remain obscured through
Saturday morning. Blank/MLV

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  29  41  35  48 /  30   0  20  30
CTB  27  37  30  43 /  10   0  20  20
HLN  23  37  30  47 /  30  10  70  50
BZN  21  35  29  45 /  60  10  60  60
WEY  22  33  28  39 /  70  50  80  70
DLN  22  37  33  47 /  40  10  60  50
HVR  26  40  27  46 /  40  10  40  40
LWT  27  43  31  48 /  40  10  30  50

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY from 5 PM Saturday to 5 AM MST Monday
FOR ELEVATIONS ABOVE 5000 FEET FOR Central and Southern Lewis
and Clark...Jefferson...Northern Rocky Mountain Front...Southern
Rocky Mountain Front.

HIGH WIND WATCH from late Saturday night through Sunday
afternoon Eastern Glacier...Eastern Pondera...Eastern Teton...
Liberty...Toole.

HIGH WIND WARNING from 2 AM Saturday to 5 PM MST Sunday Northern
Rocky Mountain Front...Southern Rocky Mountain Front.

WINTER STORM WATCH from Saturday afternoon through late Sunday
night FOR ELEVATIONS ABOVE 6000 FEET FOR Beaverhead...Gallatin...
Madison.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls










000
FXUS65 KTFX 200356
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
855 PM MST Fri Dec 19 2014

.UPDATE...
Another night of quiet weather conditions across central and
southwest MT.  Latest satellite imagery shows the shortwave trof
that was in western MT this aftn has moved slightly quicker than
some forecast models were indicating.  The trof axis is currently
between Great Falls and Lewistown and making steady progress
eastward.  The moisture plume accompanying the trof has been
thinning as it moves along, as evidenced by very light and spotty
showers seen on latest radar imagery.  Even with the few spots where
radar echoes may be a bit better defined, it appears that little if
any precipitation is reaching the ground, especially in the lower
elevations.  Given the system`s quicker progress and minimal
precipitation coverage, main adjustment this evening was to reduce
the chances of precipitation by 20-30% over most of the forecast
area between now and 6am Saturday.  Rest of the current forecast is
in good shape.
Waranauskas

&&

.DISCUSSION...

Tonight through Sunday...
An upper level short wave trof and associated Pacific cold front
will move through the region overnight. This will case periods of
light snow across the Southwest. Warmer air in the southwest flow
ahead of this system could lift over a colder airmass in place
over eastern portions of north-central Montana. This creates a
possible light freezing rain scenario tonight. Have added freezing
rain to the forecast, but otherwise do not have enough confidence
to issue any advisories. Will continue to monitor once light
precipitation begins to spread through this area tonight.

Surface pressure falls are already causing wind gusts to pick up
at Deep Creek along the northern Rocky Mtn Front. Short term
guidance added confidence that wind gusts will briefly reach near
60 mph at isolated locations in this area early Saturday as the
front passes. Issued a high wind warning to cover this situation,
even knowing that gusts will taper Saturday. The high wind warning
continues on through Sunday as a much stronger downslope wind
signature appears with a strong lee trough and synoptic
subsidence. Issued a high wind watch extending east off the Rocky
Mountain front on Sunday to evaluate the possibility of a more
widespread high wind event Sunday.

An atmospheric river event is developing over the Pacific
Northwest Saturday night and Sunday. This affects mainly southwest
Montana...but heavy snow will accumulate along the Rocky
Mountains, shifting from north to south through Sunday. Snow
accumulations at pass level remain below 8 inches in 24 hours, so
issued a winter weather advisory for snow and blowing snow above
5000 feet. Downsloping winds and mild temperatures will keep any
snow accumulations within and closely adjacent to the Rocky
Mountain Front. In the southwest, snow accumulations could exceed
8 inches from 06Z Sunday through 06Z Monday. Snow levels are
forecast to rise above 5000 feet on Sunday, with rain possible in
the valleys. Will need to monitor forecast snowlevels before
upgrading to winter storm warning or dropping back to winter
weather advisory. Nutter

Sunday night through Friday...A rather active
weather pattern is setting up for much of the region for next
week. There will be several accumulating snowfall events that will
cause impacts for daily commuters and travelers. Through much of
the extended...the GFS13 and EC are in pretty good agreement.
Temperatures will be near/a bit above normal Monday and into
Tuesday...but then begin to turn colder Wednesday through Friday.
For now I used a blend of the colder models for temperatures...but
temperatures could be several degrees colder than currently
forecast should the snowpack become a bit deeper than expected.
Additionally...there is the potential for another high wind event
over portions of North Central MT on Tuesday.

In terms of precipitation...Southwest MT will continue to see
precipitation Sunday night and into Monday morning...with scattered
showers over North Central MT. The precipitation becomes
light and scattered Monday night through Tuesday. Then a another
fairly strong storm system will move through the region Wednesday
afternoon through Christmas Day. At this time...it looks like
Central and Southwest MT will see the brunt of this storm. At lower
elevations...there will be a swath of 3 to 5 inches of snow...with
around 8 to 10 inches in the mountains. It is too early to pin-point
the exact area that will see this heavier snowfall...but right now
that swath of heavier snow is forecast along a Helena to Bozeman
line. This line of heavier snow could shift a bit over the next few
days as later model runs get a better handle on the storm track.
Brusda/Blank

&&

.AVIATION...
UPDATED 0000Z.
A surface cold front associated with a weak upper-level weather
system will sweep from west to east through the forecast area this
evening. Conditions will deteriorate from west to east this evening
and tonight with mountains obscured in snow until late tonight. Have
moderate confidence in the timing of precipitation, but forecast
confidence is low for flight category cigs/vis. At KHVR, freezing
rain is possible late this evening, then should changeover to a
rain/snow mix. Rain and snow showers are expected at KGTF and KLWT
with light snow developing at KHLN and KBZN between 01z and 03z.
This is a fast-moving system with conditions improving by 12z
Saturday.

BZN TAF...as mentioned above have moderate confidence in the timing
of the threat of precipitation. Winds will remain light and variable
despite the cold frontal passage that is expected by 04z. Although
there is a prob group for MVFR conditions in snow from 03z to
07z..there could even be a brief period of IFR conditions in
steadier snow during this same time frame. Should these IFR
conditions develop they would last no more than an hour. Mountains
will become obscured later this evening and remain obscured through
Saturday morning. Blank/MLV

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  29  41  35  48 /  30   0  20  30
CTB  27  37  30  43 /  10   0  20  20
HLN  23  37  30  47 /  30  10  70  50
BZN  21  35  29  45 /  60  10  60  60
WEY  22  33  28  39 /  70  50  80  70
DLN  22  37  33  47 /  40  10  60  50
HVR  26  40  27  46 /  40  10  40  40
LWT  27  43  31  48 /  40  10  30  50

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY from 5 PM Saturday to 5 AM MST Monday
FOR ELEVATIONS ABOVE 5000 FEET FOR Central and Southern Lewis
and Clark...Jefferson...Northern Rocky Mountain Front...Southern
Rocky Mountain Front.

HIGH WIND WATCH from late Saturday night through Sunday
afternoon Eastern Glacier...Eastern Pondera...Eastern Teton...
Liberty...Toole.

HIGH WIND WARNING from 2 AM Saturday to 5 PM MST Sunday Northern
Rocky Mountain Front...Southern Rocky Mountain Front.

WINTER STORM WATCH from Saturday afternoon through late Sunday
night FOR ELEVATIONS ABOVE 6000 FEET FOR Beaverhead...Gallatin...
Madison.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls











000
FXUS65 KTFX 192345
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
445 PM MST Fri Dec 19 2014

Updated Aviation

.DISCUSSION...

Tonight through Sunday...
An upper level short wave trof and associated Pacific cold front
will move through the region overnight. This will case periods of
light snow across the Southwest. Warmer air in the southwest flow
ahead of this system could lift over a colder airmass in place
over eastern portions of north-central Montana. This creates a
possible light freezing rain scenario tonight. Have added freezing
rain to the forecast, but otherwise do not have enough confidence
to issue any advisories. Will continue to monitor once light
precipitation begins to spread through this area tonight.

Surface pressure falls are already causing wind gusts to pick up
at Deep Creek along the northern Rocky Mtn Front. Short term
guidance added confidence that wind gusts will briefly reach near
60 mph at isolated locations in this area early Saturday as the
front passes. Issued a high wind warning to cover this situation,
even knowing that gusts will taper Saturday. The high wind warning
continues on through Sunday as a much stronger downslope wind
signature appears with a strong lee trough and synoptic
subsidence. Issued a high wind watch extending east off the Rocky
Mountain front on Sunday to evaluate the possibility of a more
widespread high wind event Sunday.

An atmospheric river event is developing over the Pacific
Northwest Saturday night and Sunday. This affects mainly southwest
Montana...but heavy snow will accumulate along the Rocky
Mountains, shifting from north to south through Sunday. Snow
accumulations at pass level remain below 8 inches in 24 hours, so
issued a winter weather advisory for snow and blowing snow above
5000 feet. Downsloping winds and mild temperatures will keep any
snow accumulations within and closely adjacent to the Rocky
Mountain Front. In the southwest, snow accumulations could exceed
8 inches from 06Z Sunday through 06Z Monday. Snow levels are
forecast to rise above 5000 feet on Sunday, with rain possible in
the valleys. Will need to monitor forecast snowlevels before
upgrading to winter storm warning or dropping back to winter
weather advisory. Nutter

Sunday night through Friday...A rather active
weather pattern is setting up for much of the region for next
week. There will be several accumulating snowfall events that will
cause impacts for daily commuters and travelers. Through much of
the extended...the GFS13 and EC are in pretty good agreement.
Temperatures will be near/a bit above normal Monday and into
Tuesday...but then begin to turn colder Wednesday through Friday.
For now I used a blend of the colder models for temperatures...but
temperatures could be several degrees colder than currently
forecast should the snowpack become a bit deeper than expected.
Additionally...there is the potential for another high wind event
over portions of North Central MT on Tuesday.

In terms of precipitation...Southwest MT will continue to see
precipitation Sunday night and into Monday morning...with scattered
showers over North Central MT. The precipitation becomes
light and scattered Monday night through Tuesday. Then a another
fairly strong storm system will move through the region Wednesday
afternoon through Christmas Day. At this time...it looks like
Central and Southwest MT will see the brunt of this storm. At lower
elevations...there will be a swath of 3 to 5 inches of snow...with
around 8 to 10 inches in the mountains. It is too early to pin-point
the exact area that will see this heavier snowfall...but right now
that swath of heavier snow is forecast along a Helena to Bozeman
line. This line of heavier snow could shift a bit over the next few
days as later model runs get a better handle on the storm track.
Brusda/Blank

&&

.AVIATION...
UPDATED 0000Z.
A surface cold front associated with a weak upper-level weather
system will sweep from west to east through the forecast area this
evening. Conditions will deteriorate from west to east this evening
and tonight with mountains obscured in snow until late tonight. Have
moderate confidence in the timing of precipitation, but forecast
confidence is low for flight category cigs/vis. At KHVR, freezing
rain is possible late this evening, then should changeover to a
rain/snow mix. Rain and snow showers are expected at KGTF and KLWT
with light snow developing at KHLN and KBZN between 01z and 03z.
This is a fast-moving system with conditions improving by 12z
Saturday.

BZN TAF...as mentioned above have moderate confidence in the timing
of the threat of precipitation. Winds will remain light and variable
despite the cold frontal passage that is expected by 04z. Although
there is a prob group for MVFR conditions in snow from 03z to
07z..there could even be a brief period of IFR conditions in
steadier snow during this same time frame. Should these IFR
conditions develop they would last no more than an hour. Mountains
will become obscured later this evening and remain obscured through
Saturday morning. Blank/MLV

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  29  41  35  48 /  30   0  20  30
CTB  27  37  30  43 /  10   0  20  20
HLN  23  37  30  47 /  30  10  70  50
BZN  21  35  29  45 /  60  10  60  60
WEY  22  33  28  39 /  70  50  80  70
DLN  22  37  33  47 /  40  10  60  50
HVR  26  40  27  46 /  40  10  40  40
LWT  27  43  31  48 /  40  10  30  50

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY from 5 PM Saturday to 5 AM MST Monday
FOR ELEVATIONS ABOVE 5000 FEET FOR Central and Southern Lewis
and Clark...Jefferson...Northern Rocky Mountain Front...Southern
Rocky Mountain Front.

HIGH WIND WATCH from late Saturday night through Sunday
afternoon Eastern Glacier...Eastern Pondera...Eastern Teton...
Liberty...Toole.

HIGH WIND WARNING from 2 AM Saturday to 5 PM MST Sunday Northern
Rocky Mountain Front...Southern Rocky Mountain Front.

WINTER STORM WATCH from Saturday afternoon through late Sunday
night FOR ELEVATIONS ABOVE 6000 FEET FOR Beaverhead...Gallatin...
Madison.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls








000
FXUS65 KTFX 192345
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
445 PM MST Fri Dec 19 2014

Updated Aviation

.DISCUSSION...

Tonight through Sunday...
An upper level short wave trof and associated Pacific cold front
will move through the region overnight. This will case periods of
light snow across the Southwest. Warmer air in the southwest flow
ahead of this system could lift over a colder airmass in place
over eastern portions of north-central Montana. This creates a
possible light freezing rain scenario tonight. Have added freezing
rain to the forecast, but otherwise do not have enough confidence
to issue any advisories. Will continue to monitor once light
precipitation begins to spread through this area tonight.

Surface pressure falls are already causing wind gusts to pick up
at Deep Creek along the northern Rocky Mtn Front. Short term
guidance added confidence that wind gusts will briefly reach near
60 mph at isolated locations in this area early Saturday as the
front passes. Issued a high wind warning to cover this situation,
even knowing that gusts will taper Saturday. The high wind warning
continues on through Sunday as a much stronger downslope wind
signature appears with a strong lee trough and synoptic
subsidence. Issued a high wind watch extending east off the Rocky
Mountain front on Sunday to evaluate the possibility of a more
widespread high wind event Sunday.

An atmospheric river event is developing over the Pacific
Northwest Saturday night and Sunday. This affects mainly southwest
Montana...but heavy snow will accumulate along the Rocky
Mountains, shifting from north to south through Sunday. Snow
accumulations at pass level remain below 8 inches in 24 hours, so
issued a winter weather advisory for snow and blowing snow above
5000 feet. Downsloping winds and mild temperatures will keep any
snow accumulations within and closely adjacent to the Rocky
Mountain Front. In the southwest, snow accumulations could exceed
8 inches from 06Z Sunday through 06Z Monday. Snow levels are
forecast to rise above 5000 feet on Sunday, with rain possible in
the valleys. Will need to monitor forecast snowlevels before
upgrading to winter storm warning or dropping back to winter
weather advisory. Nutter

Sunday night through Friday...A rather active
weather pattern is setting up for much of the region for next
week. There will be several accumulating snowfall events that will
cause impacts for daily commuters and travelers. Through much of
the extended...the GFS13 and EC are in pretty good agreement.
Temperatures will be near/a bit above normal Monday and into
Tuesday...but then begin to turn colder Wednesday through Friday.
For now I used a blend of the colder models for temperatures...but
temperatures could be several degrees colder than currently
forecast should the snowpack become a bit deeper than expected.
Additionally...there is the potential for another high wind event
over portions of North Central MT on Tuesday.

In terms of precipitation...Southwest MT will continue to see
precipitation Sunday night and into Monday morning...with scattered
showers over North Central MT. The precipitation becomes
light and scattered Monday night through Tuesday. Then a another
fairly strong storm system will move through the region Wednesday
afternoon through Christmas Day. At this time...it looks like
Central and Southwest MT will see the brunt of this storm. At lower
elevations...there will be a swath of 3 to 5 inches of snow...with
around 8 to 10 inches in the mountains. It is too early to pin-point
the exact area that will see this heavier snowfall...but right now
that swath of heavier snow is forecast along a Helena to Bozeman
line. This line of heavier snow could shift a bit over the next few
days as later model runs get a better handle on the storm track.
Brusda/Blank

&&

.AVIATION...
UPDATED 0000Z.
A surface cold front associated with a weak upper-level weather
system will sweep from west to east through the forecast area this
evening. Conditions will deteriorate from west to east this evening
and tonight with mountains obscured in snow until late tonight. Have
moderate confidence in the timing of precipitation, but forecast
confidence is low for flight category cigs/vis. At KHVR, freezing
rain is possible late this evening, then should changeover to a
rain/snow mix. Rain and snow showers are expected at KGTF and KLWT
with light snow developing at KHLN and KBZN between 01z and 03z.
This is a fast-moving system with conditions improving by 12z
Saturday.

BZN TAF...as mentioned above have moderate confidence in the timing
of the threat of precipitation. Winds will remain light and variable
despite the cold frontal passage that is expected by 04z. Although
there is a prob group for MVFR conditions in snow from 03z to
07z..there could even be a brief period of IFR conditions in
steadier snow during this same time frame. Should these IFR
conditions develop they would last no more than an hour. Mountains
will become obscured later this evening and remain obscured through
Saturday morning. Blank/MLV

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  29  41  35  48 /  30   0  20  30
CTB  27  37  30  43 /  10   0  20  20
HLN  23  37  30  47 /  30  10  70  50
BZN  21  35  29  45 /  60  10  60  60
WEY  22  33  28  39 /  70  50  80  70
DLN  22  37  33  47 /  40  10  60  50
HVR  26  40  27  46 /  40  10  40  40
LWT  27  43  31  48 /  40  10  30  50

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY from 5 PM Saturday to 5 AM MST Monday
FOR ELEVATIONS ABOVE 5000 FEET FOR Central and Southern Lewis
and Clark...Jefferson...Northern Rocky Mountain Front...Southern
Rocky Mountain Front.

HIGH WIND WATCH from late Saturday night through Sunday
afternoon Eastern Glacier...Eastern Pondera...Eastern Teton...
Liberty...Toole.

HIGH WIND WARNING from 2 AM Saturday to 5 PM MST Sunday Northern
Rocky Mountain Front...Southern Rocky Mountain Front.

WINTER STORM WATCH from Saturday afternoon through late Sunday
night FOR ELEVATIONS ABOVE 6000 FEET FOR Beaverhead...Gallatin...
Madison.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls









000
FXUS65 KTFX 192207
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
307 PM MST Fri Dec 19 2014

.DISCUSSION...

Tonight through Sunday...
An upper level short wave trof and associated Pacific cold front
will move through the region overnight. This will case periods of
light snow across the Southwest. Warmer air in the southwest flow
ahead of this system could lift over a colder airmass in place
over eastern portions of north-central Montana. This creates a
possible light freezing rain scenario tonight. Have added freezing
rain to the forecast, but otherwise do not have enough confidence
to issue any advisories. Will continue to monitor once light
precipitation begins to spread through this area tonight.

Surface pressure falls are already causing wind gusts to pick up
at Deep Creek along the northern Rocky Mtn Front. Short term
guidance added confidence that wind gusts will briefly reach near
60 mph at isolated locations in this area early Saturday as the
front passes. Issued a high wind warning to cover this situation,
even knowing that gusts will taper Saturday. The high wind warning
continues on through Sunday as a much stronger downslope wind
signature appears with a strong lee trough and synoptic
subsidence. Issued a high wind watch extending east off the Rocky
Mountain front on Sunday to evaluate the possibility of a more
widespread high wind event Sunday.

An atmospheric river event is developing over the Pacific
Northwest Saturday night and Sunday. This affects mainly southwest
Montana...but heavy snow will accumulate along the Rocky
Mountains, shifting from north to south through Sunday. Snow
accumulations at pass level remain below 8 inches in 24 hours, so
issued a winter weather advisory for snow and blowing snow above
5000 feet. Downsloping winds and mild temperatures will keep any
snow accumulations within and closely adjacent to the Rocky
Mountain Front. In the southwest, snow accumulations could exceed
8 inches from 06Z Sunday through 06Z Monday. Snow levels are
forecast to rise above 5000 feet on Sunday, with rain possible in
the valleys. Will need to monitor forecast snowlevels before
upgrading to winter storm warning or dropping back to winter
weather advisory. Nutter

Sunday night through Friday...A rather active
weather pattern is setting up for much of the region for next
week. There will be several accumulating snowfall events that will
cause impacts for daily commuters and travelers. Through much of
the extended...the GFS13 and EC are in pretty good agreement.
Temperatures will be near/a bit above normal Monday and into
Tuesday...but then begin to turn colder Wednesday through Friday.
For now I used a blend of the colder models for temperatures...but
temperatures could be several degrees colder than currently
forecast should the snowpack become a bit deeper than expected.
Additionally...there is the potential for another high wind event
over portions of North Central MT on Tuesday.

In terms of precipitation...Southwest MT will continue to see
precipitation Sunday night and into Monday morning...with scattered
showers over North Central MT. The precipitation becomes
light and scattered Monday night through Tuesday. Then a another
fairly strong storm system will move through the region Wednesday
afternoon through Christmas Day. At this time...it looks like
Central and Southwest MT will see the brunt of this storm. At lower
elevations...there will be a swath of 3 to 5 inches of snow...with
around 8 to 10 inches in the mountains. It is too early to pin-point
the exact area that will see this heavier snowfall...but right now
that swath of heavier snow is forecast along a Helena to Bozeman
line. This line of heavier snow could shift a bit over the next few
days as later model runs get a better handle on the storm track.
Brusda/Blank

&&

.AVIATION...
UPDATED 1755Z.
A cold front will sweep from west to east through the forecast area
this evening and it will be followed by a weather disturbance aloft.
Expect generally VFR conditions however mountains will be obscured
in snow until late tonight. Have moderate confidence in the timing
of the weather and how low ceilings will go but for the plains have
low confidence in the type of precipitation. For instance at
KGTF/KLWT/KHVR precipitation could be either rain or snow or even
freezing rain. Should freezing rain develop do not think it would
last more than an hour. Over the plains skies should clear rapidly
behind the weather disturbance.

BZN taf...as mentioned above have moderate confidence in the timing
of the threat of precipitation. The cold front should move through
the area during the 04z to 05z time frame but should not notice much
of a change with winds. That is the winds should remain light.
Although there is a prob group for MVFR conditions in snow from 04z
to 08z..there could even be a brief period of IFR conditions in snow
during this same time frame. Should these IFR conditions develop
they would last no more than an hour. Also note that nearby
mountains could be obscured in snow during the 04z to 08z time
frame. Blank

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  29  41  35  48 /  30   0  20  30
CTB  27  37  30  43 /  10   0  20  20
HLN  23  37  30  47 /  30  10  70  50
BZN  21  35  29  45 /  60  10  60  60
WEY  22  33  28  39 /  70  50  80  70
DLN  22  37  33  47 /  40  10  60  50
HVR  26  40  27  46 /  40  10  40  40
LWT  27  43  31  48 /  40  10  30  50

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY from 5 PM Saturday to 5 AM MST Monday
FOR ELEVATIONS ABOVE 5000 FEET FOR Central and Southern Lewis
and Clark...Jefferson...Northern Rocky Mountain Front...Southern
Rocky Mountain Front.

HIGH WIND WATCH from late Saturday night through Sunday
afternoon Eastern Glacier...Eastern Pondera...Eastern Teton...
Liberty...Toole.

HIGH WIND WARNING from 2 AM Saturday to 5 PM MST Sunday Northern
Rocky Mountain Front...Southern Rocky Mountain Front.

WINTER STORM WATCH from Saturday afternoon through late Sunday
night FOR ELEVATIONS ABOVE 6000 FEET FOR Beaverhead...Gallatin...
Madison.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 192207
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
307 PM MST Fri Dec 19 2014

.DISCUSSION...

Tonight through Sunday...
An upper level short wave trof and associated Pacific cold front
will move through the region overnight. This will case periods of
light snow across the Southwest. Warmer air in the southwest flow
ahead of this system could lift over a colder airmass in place
over eastern portions of north-central Montana. This creates a
possible light freezing rain scenario tonight. Have added freezing
rain to the forecast, but otherwise do not have enough confidence
to issue any advisories. Will continue to monitor once light
precipitation begins to spread through this area tonight.

Surface pressure falls are already causing wind gusts to pick up
at Deep Creek along the northern Rocky Mtn Front. Short term
guidance added confidence that wind gusts will briefly reach near
60 mph at isolated locations in this area early Saturday as the
front passes. Issued a high wind warning to cover this situation,
even knowing that gusts will taper Saturday. The high wind warning
continues on through Sunday as a much stronger downslope wind
signature appears with a strong lee trough and synoptic
subsidence. Issued a high wind watch extending east off the Rocky
Mountain front on Sunday to evaluate the possibility of a more
widespread high wind event Sunday.

An atmospheric river event is developing over the Pacific
Northwest Saturday night and Sunday. This affects mainly southwest
Montana...but heavy snow will accumulate along the Rocky
Mountains, shifting from north to south through Sunday. Snow
accumulations at pass level remain below 8 inches in 24 hours, so
issued a winter weather advisory for snow and blowing snow above
5000 feet. Downsloping winds and mild temperatures will keep any
snow accumulations within and closely adjacent to the Rocky
Mountain Front. In the southwest, snow accumulations could exceed
8 inches from 06Z Sunday through 06Z Monday. Snow levels are
forecast to rise above 5000 feet on Sunday, with rain possible in
the valleys. Will need to monitor forecast snowlevels before
upgrading to winter storm warning or dropping back to winter
weather advisory. Nutter

Sunday night through Friday...A rather active
weather pattern is setting up for much of the region for next
week. There will be several accumulating snowfall events that will
cause impacts for daily commuters and travelers. Through much of
the extended...the GFS13 and EC are in pretty good agreement.
Temperatures will be near/a bit above normal Monday and into
Tuesday...but then begin to turn colder Wednesday through Friday.
For now I used a blend of the colder models for temperatures...but
temperatures could be several degrees colder than currently
forecast should the snowpack become a bit deeper than expected.
Additionally...there is the potential for another high wind event
over portions of North Central MT on Tuesday.

In terms of precipitation...Southwest MT will continue to see
precipitation Sunday night and into Monday morning...with scattered
showers over North Central MT. The precipitation becomes
light and scattered Monday night through Tuesday. Then a another
fairly strong storm system will move through the region Wednesday
afternoon through Christmas Day. At this time...it looks like
Central and Southwest MT will see the brunt of this storm. At lower
elevations...there will be a swath of 3 to 5 inches of snow...with
around 8 to 10 inches in the mountains. It is too early to pin-point
the exact area that will see this heavier snowfall...but right now
that swath of heavier snow is forecast along a Helena to Bozeman
line. This line of heavier snow could shift a bit over the next few
days as later model runs get a better handle on the storm track.
Brusda/Blank

&&

.AVIATION...
UPDATED 1755Z.
A cold front will sweep from west to east through the forecast area
this evening and it will be followed by a weather disturbance aloft.
Expect generally VFR conditions however mountains will be obscured
in snow until late tonight. Have moderate confidence in the timing
of the weather and how low ceilings will go but for the plains have
low confidence in the type of precipitation. For instance at
KGTF/KLWT/KHVR precipitation could be either rain or snow or even
freezing rain. Should freezing rain develop do not think it would
last more than an hour. Over the plains skies should clear rapidly
behind the weather disturbance.

BZN taf...as mentioned above have moderate confidence in the timing
of the threat of precipitation. The cold front should move through
the area during the 04z to 05z time frame but should not notice much
of a change with winds. That is the winds should remain light.
Although there is a prob group for MVFR conditions in snow from 04z
to 08z..there could even be a brief period of IFR conditions in snow
during this same time frame. Should these IFR conditions develop
they would last no more than an hour. Also note that nearby
mountains could be obscured in snow during the 04z to 08z time
frame. Blank

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  29  41  35  48 /  30   0  20  30
CTB  27  37  30  43 /  10   0  20  20
HLN  23  37  30  47 /  30  10  70  50
BZN  21  35  29  45 /  60  10  60  60
WEY  22  33  28  39 /  70  50  80  70
DLN  22  37  33  47 /  40  10  60  50
HVR  26  40  27  46 /  40  10  40  40
LWT  27  43  31  48 /  40  10  30  50

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY from 5 PM Saturday to 5 AM MST Monday
FOR ELEVATIONS ABOVE 5000 FEET FOR Central and Southern Lewis
and Clark...Jefferson...Northern Rocky Mountain Front...Southern
Rocky Mountain Front.

HIGH WIND WATCH from late Saturday night through Sunday
afternoon Eastern Glacier...Eastern Pondera...Eastern Teton...
Liberty...Toole.

HIGH WIND WARNING from 2 AM Saturday to 5 PM MST Sunday Northern
Rocky Mountain Front...Southern Rocky Mountain Front.

WINTER STORM WATCH from Saturday afternoon through late Sunday
night FOR ELEVATIONS ABOVE 6000 FEET FOR Beaverhead...Gallatin...
Madison.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 191755
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1055 AM MST Fri Dec 19 2014

UPDATED AVIATION DISCUSSION

.UPDATE...

Webcams this morning show periods of snow occurring across the
southwest, including Monida and Raynolds passes, Big Sky and West
Yellowstone. Raised near-term PoPs for today and tonight based on
the NAM to reflect this early activity. Snow accumulation of 1 to
3 inches is expected for these areas through Saturday morning. Winter
weather advisories will not be issued for tonight, although
travelers through this area should expect snow covered roads.
Winds speeds along the Rocky Mountain front were raised along the
Rocky Mountain Front as a lee trough begins to form. Areas of
light freezing rain remain possible tonight for areas generally
north and east of the Bears Paw Mountains. Nutter

&&

.AVIATION...
UPDATED 1755Z.
A cold front will sweep from west to east through the forecast area
this evening and it will be followed by a weather disturbance aloft.
Expect generally VFR conditions however mountains will be obscured
in snow until late tonight. Have moderate confidence in the timing
of the weather and how low ceilings will go but for the plains have
low confidence in the type of precipitation. For instance at
KGTF/KLWT/KHVR precipitation could be either rain or snow or even
freezing rain. Should freezing rain develop do not think it would
last more than an hour. Over the plains skies should clear rapidly
behind the weather disturbance.

BZN taf...as mentioned above have moderate confidence in the timing
of the threat of precipitation. The cold front should move through
the area during the 04z to 05z time frame but should not notice much
of a change with winds. That is the winds should remain light.
Although there is a prob group for MVFR conditions in snow from 04z
to 08z..there could even be a brief period of IFR conditions in snow
during this same time frame. Should these IFR conditions develop
they would last no more than an hour. Also note that nearby
mountains could be obscured in snow during the 04z to 08z time
frame. Blank

&&

.PREV DISCUSSION...
/ISSUED 438 AM MST Fri Dec 19 2014/

Tonight through Sunday...A high pressure ridge will be over the
Rockies and moving over the zones during the day. To the west, a low
pressure trof will move over the West Coast during the day. Decent
dynamics develop as the trof crosses the Rockies although this will
be a fast-moving feature and little time for development of weather.
Best lift with this system will be Friday night over the southwest
zones. However, a chance for mixed snow and rain are expected
tonight over central and northern portions of the CWA. Will include
some freezing rain in the grids after midnight as the surface
conditions cool. The upper level trof will move over the zones by
early Saturday and weak ridging will be in place to the west and
moving across the zones during the day. A strong jet at upper levels
will be over the Pacific Northwest Saturday and spread east over the
zones Saturday night and Sunday. Mid-level winds will increase to
45+ kts Saturday night and Sunday. This will bring very strong winds
across the Rockies and adjacent plains. Some stability develops at
lower levels after midnight and the will bring the best chance for
strong winds spreading east. Currently, have some gusts above
58 mph over the Rockies but because of uncertainty will hold off on
statements. Some strong winds as well at higher elevations will also
occur across Southwest Montana by Sunday and will have to be
monitored. Widespread precipitation will develop with the approach
of a shortwave associated with these strong winds Saturday night
and, once again, the chance of freezing rain will develop and will
be included in the grids after midnight into Sunday morning. Some
higher snow accumulations are expected at higher elevations in the
southwest zones but widespread heavy snow is not expected. Zelzer

Sunday night through Friday...A rather active weather pattern is
setting up for much of the region for next week. At this time...we
are not expecting significant snow storms...but rather several
accumulating snowfall events that will cause impacts for daily
commuters and travelers. Through much of the extended...the GFS13
and EC are in pretty good agreement. Temperatures will be near/a bit
above normal Monday and into Tuesday...but then begin to turn colder
Wednesday through Friday. For now I used a lower blend of the colder
models for temperatures...but temperatures could be several degrees
colder than currently forecast should the snowpack become a bit
deeper than expected. Additionally...there is the potential for
another high wind event over portions of North Central MT on Tuesday.

In terms of precipitation...Southwest MT will continue to see
precipitation Sunday night and into Monday morning...with scattered
showers over North Central MT. The precipitation becomes fairly
light and scattered Monday night through Tuesday. Then a fairly
strong storm system will move through the region Wednesday afternoon
through Christmas Day. At this time...it looks like Central and
Southwest MT will see the brunt of this storm. At lower
elevations...there will be a swath of 3 to 5 inches of snow...with
around 8 to 10 inches in the mountains. It is too early to pin-point
the exact area that will see this heavier snowfall...but right now
that swath of heavier snow is forecast along a Helena to Bozeman
line. This line of heavier snow could shift a bit over the next few
days as later model runs get a better handle on the storm track.
Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  42  28  40  34 /  10  30  10  20
CTB  40  26  36  29 /  10  10   0  20
HLN  37  22  36  28 /  30  50  10  40
BZN  35  18  33  27 /  30  60  10  50
WEY  33  20  32  27 /  60  60  40  70
DLN  38  20  35  31 /  50  50  10  50
HVR  39  26  39  26 /   0  30  10  20
LWT  44  25  41  29 /   0  30  10  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls









000
FXUS65 KTFX 191755
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1055 AM MST Fri Dec 19 2014

UPDATED AVIATION DISCUSSION

.UPDATE...

Webcams this morning show periods of snow occurring across the
southwest, including Monida and Raynolds passes, Big Sky and West
Yellowstone. Raised near-term PoPs for today and tonight based on
the NAM to reflect this early activity. Snow accumulation of 1 to
3 inches is expected for these areas through Saturday morning. Winter
weather advisories will not be issued for tonight, although
travelers through this area should expect snow covered roads.
Winds speeds along the Rocky Mountain front were raised along the
Rocky Mountain Front as a lee trough begins to form. Areas of
light freezing rain remain possible tonight for areas generally
north and east of the Bears Paw Mountains. Nutter

&&

.AVIATION...
UPDATED 1755Z.
A cold front will sweep from west to east through the forecast area
this evening and it will be followed by a weather disturbance aloft.
Expect generally VFR conditions however mountains will be obscured
in snow until late tonight. Have moderate confidence in the timing
of the weather and how low ceilings will go but for the plains have
low confidence in the type of precipitation. For instance at
KGTF/KLWT/KHVR precipitation could be either rain or snow or even
freezing rain. Should freezing rain develop do not think it would
last more than an hour. Over the plains skies should clear rapidly
behind the weather disturbance.

BZN taf...as mentioned above have moderate confidence in the timing
of the threat of precipitation. The cold front should move through
the area during the 04z to 05z time frame but should not notice much
of a change with winds. That is the winds should remain light.
Although there is a prob group for MVFR conditions in snow from 04z
to 08z..there could even be a brief period of IFR conditions in snow
during this same time frame. Should these IFR conditions develop
they would last no more than an hour. Also note that nearby
mountains could be obscured in snow during the 04z to 08z time
frame. Blank

&&

.PREV DISCUSSION...
/ISSUED 438 AM MST Fri Dec 19 2014/

Tonight through Sunday...A high pressure ridge will be over the
Rockies and moving over the zones during the day. To the west, a low
pressure trof will move over the West Coast during the day. Decent
dynamics develop as the trof crosses the Rockies although this will
be a fast-moving feature and little time for development of weather.
Best lift with this system will be Friday night over the southwest
zones. However, a chance for mixed snow and rain are expected
tonight over central and northern portions of the CWA. Will include
some freezing rain in the grids after midnight as the surface
conditions cool. The upper level trof will move over the zones by
early Saturday and weak ridging will be in place to the west and
moving across the zones during the day. A strong jet at upper levels
will be over the Pacific Northwest Saturday and spread east over the
zones Saturday night and Sunday. Mid-level winds will increase to
45+ kts Saturday night and Sunday. This will bring very strong winds
across the Rockies and adjacent plains. Some stability develops at
lower levels after midnight and the will bring the best chance for
strong winds spreading east. Currently, have some gusts above
58 mph over the Rockies but because of uncertainty will hold off on
statements. Some strong winds as well at higher elevations will also
occur across Southwest Montana by Sunday and will have to be
monitored. Widespread precipitation will develop with the approach
of a shortwave associated with these strong winds Saturday night
and, once again, the chance of freezing rain will develop and will
be included in the grids after midnight into Sunday morning. Some
higher snow accumulations are expected at higher elevations in the
southwest zones but widespread heavy snow is not expected. Zelzer

Sunday night through Friday...A rather active weather pattern is
setting up for much of the region for next week. At this time...we
are not expecting significant snow storms...but rather several
accumulating snowfall events that will cause impacts for daily
commuters and travelers. Through much of the extended...the GFS13
and EC are in pretty good agreement. Temperatures will be near/a bit
above normal Monday and into Tuesday...but then begin to turn colder
Wednesday through Friday. For now I used a lower blend of the colder
models for temperatures...but temperatures could be several degrees
colder than currently forecast should the snowpack become a bit
deeper than expected. Additionally...there is the potential for
another high wind event over portions of North Central MT on Tuesday.

In terms of precipitation...Southwest MT will continue to see
precipitation Sunday night and into Monday morning...with scattered
showers over North Central MT. The precipitation becomes fairly
light and scattered Monday night through Tuesday. Then a fairly
strong storm system will move through the region Wednesday afternoon
through Christmas Day. At this time...it looks like Central and
Southwest MT will see the brunt of this storm. At lower
elevations...there will be a swath of 3 to 5 inches of snow...with
around 8 to 10 inches in the mountains. It is too early to pin-point
the exact area that will see this heavier snowfall...but right now
that swath of heavier snow is forecast along a Helena to Bozeman
line. This line of heavier snow could shift a bit over the next few
days as later model runs get a better handle on the storm track.
Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  42  28  40  34 /  10  30  10  20
CTB  40  26  36  29 /  10  10   0  20
HLN  37  22  36  28 /  30  50  10  40
BZN  35  18  33  27 /  30  60  10  50
WEY  33  20  32  27 /  60  60  40  70
DLN  38  20  35  31 /  50  50  10  50
HVR  39  26  39  26 /   0  30  10  20
LWT  44  25  41  29 /   0  30  10  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls








000
FXUS65 KTFX 191716
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1016 AM MST Fri Dec 19 2014

.UPDATE...

Webcams this morning show periods of snow occurring across the
southwest, including Monida and Raynolds passes, Big Sky and West
Yellowstone. Raised near-term PoPs for today and tonight based on
the NAM to reflect this early activity. Snow accumulation of 1 to
3 inches is expected for these areas through Saturday morning. Winter
weather advisories will not be issued for tonight, although
travelers through this area should expect snow covered roads.
Winds speeds along the Rocky Mountain front were raised along the
Rocky Mountain Front as a lee trough begins to form. Areas of
light freezing rain remain possible tonight for areas generally
north and east of the Bears Paw Mountains. Nutter

&&

.AVIATION...
UPDATED 1138Z.
Weak high pressure will generally keep the airmass dry today. To the
west, a low pressure shortwave over the West Coast will approach the
Rockies by this evening and the chance of precipitation will
increase across Central and Southwest Montana...with the best
chances over Southwest Montana. Local MVFR conditions are expected
tonight along with mountain obscuration. VFR conditions will prevail
Saturday.

Even though an upper-level ridge of high pressure will move over the
Northern Rockies tonight, Pacific moisture moving over the ridge
will keep SCT to BKN cigs with mountain obscuration likely through
Friday. TAF locations will remain dry through Friday afternoon
before the next weather system moves into the area, however light
snow showers are expected over the mountains tonight and Friday.
Southwest winds will be less than 15 kts over the plains tonight as
the ridge continues to build, but southwest winds will increase at
KCTB and KGTF again on Friday afternoon. Conditions will begin to
deteriorate from west to east on Friday afternoon and evening with
light snow developing at KBZN and KHLN by 02z Saturday. Have added
VCSH to KHVR, KGTF and KLWT by 04z Saturday. MLV

&&

.PREV DISCUSSION...
/ISSUED 438 AM MST Fri Dec 19 2014/

Tonight through Sunday...A high pressure ridge will be over the
Rockies and moving over the zones during the day. To the west, a low
pressure trof will move over the West Coast during the day. Decent
dynamics develop as the trof crosses the Rockies although this will
be a fast-moving feature and little time for development of weather.
Best lift with this system will be Friday night over the southwest
zones. However, a chance for mixed snow and rain are expected
tonight over central and northern portions of the CWA. Will include
some freezing rain in the grids after midnight as the surface
conditions cool. The upper level trof will move over the zones by
early Saturday and weak ridging will be in place to the west and
moving across the zones during the day. A strong jet at upper levels
will be over the Pacific Northwest Saturday and spread east over the
zones Saturday night and Sunday. Mid-level winds will increase to
45+ kts Saturday night and Sunday. This will bring very strong winds
across the Rockies and adjacent plains. Some stability develops at
lower levels after midnight and the will bring the best chance for
strong winds spreading east. Currently, have some gusts above
58 mph over the Rockies but because of uncertainty will hold off on
statements. Some strong winds as well at higher elevations will also
occur across Southwest Montana by Sunday and will have to be
monitored. Widespread precipitation will develop with the approach
of a shortwave associated with these strong winds Saturday night
and, once again, the chance of freezing rain will develop and will
be included in the grids after midnight into Sunday morning. Some
higher snow accumulations are expected at higher elevations in the
southwest zones but widespread heavy snow is not expected. Zelzer

Sunday night through Friday...A rather active weather pattern is
setting up for much of the region for next week. At this time...we
are not expecting significant snow storms...but rather several
accumulating snowfall events that will cause impacts for daily
commuters and travelers. Through much of the extended...the GFS13
and EC are in pretty good agreement. Temperatures will be near/a bit
above normal Monday and into Tuesday...but then begin to turn colder
Wednesday through Friday. For now I used a lower blend of the colder
models for temperatures...but temperatures could be several degrees
colder than currently forecast should the snowpack become a bit
deeper than expected. Additionally...there is the potential for
another high wind event over portions of North Central MT on Tuesday.

In terms of precipitation...Southwest MT will continue to see
precipitation Sunday night and into Monday morning...with scattered
showers over North Central MT. The precipitation becomes fairly
light and scattered Monday night through Tuesday. Then a fairly
strong storm system will move through the region Wednesday afternoon
through Christmas Day. At this time...it looks like Central and
Southwest MT will see the brunt of this storm. At lower
elevations...there will be a swath of 3 to 5 inches of snow...with
around 8 to 10 inches in the mountains. It is too early to pin-point
the exact area that will see this heavier snowfall...but right now
that swath of heavier snow is forecast along a Helena to Bozeman
line. This line of heavier snow could shift a bit over the next few
days as later model runs get a better handle on the storm track.
Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  42  28  40  34 /  10  30  10  20
CTB  40  26  36  29 /  10  10   0  20
HLN  37  22  36  28 /  30  50  10  40
BZN  35  18  33  27 /  30  60  10  50
WEY  33  20  32  27 /  60  60  40  70
DLN  38  20  35  31 /  50  50  10  50
HVR  39  26  39  26 /   0  30  10  20
LWT  44  25  41  29 /   0  30  10  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 191138
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
438 AM MST Fri Dec 19 2014

.DISCUSSION...

Tonight through Sunday...A high pressure ridge will be over the
Rockies and moving over the zones during the day. To the west, a low
pressure trof will move over the West Coast during the day. Decent
dynamics develop as the trof crosses the Rockies although this will
be a fast-moving feature and little time for development of weather.
Best lift with this system will be Friday night over the southwest
zones. However, a chance for mixed snow and rain are expected
tonight over central and northern portions of the CWA. Will include
some freezing rain in the grids after midnight as the surface
conditions cool. The upper level trof will move over the zones by
early Saturday and weak ridging will be in place to the west and
moving across the zones during the day. A strong jet at upper levels
will be over the Pacific Northwest Saturday and spread east over the
zones Saturday night and Sunday. Mid-level winds will increase to
45+ kts Saturday night and Sunday. This will bring very strong winds
across the Rockies and adjacent plains. Some stability develops at
lower levels after midnight and the will bring the best chance for
strong winds spreading east. Currently, have some gusts above
58 mph over the Rockies but because of uncertainty will hold off on
statements. Some strong winds as well at higher elevations will also
occur across Southwest Montana by Sunday and will have to be
monitored. Widespread precipitation will develop with the approach
of a shortwave associated with these strong winds Saturday night
and, once again, the chance of freezing rain will develop and will
be included in the grids after midnight into Sunday morning. Some
higher snow accumulations are expected at higher elevations in the
southwest zones but widespread heavy snow is not expected. Zelzer

Sunday night through Friday...A rather active weather pattern is
setting up for much of the region for next week. At this time...we
are not expecting significant snow storms...but rather several
accumulating snowfall events that will cause impacts for daily
commuters and travelers. Through much of the extended...the GFS13
and EC are in pretty good agreement. Temperatures will be near/a bit
above normal Monday and into Tuesday...but then begin to turn colder
Wednesday through Friday. For now I used a lower blend of the colder
models for temperatures...but temperatures could be several degrees
colder than currently forecasted should the snowpack become a bit
deeper than expected. Additionally...there is the potential for
another high wind event over portions of North Central MT on Tuesday.

In terms of precipitation...Southwest MT will continue to see
precipitation Sunday night and into Monday morning...with scattered
showers over North Central MT. The precipitation becomes fairly
light and scattered Monday night through Tuesday. Then a fairly
strong storm system will move through the region Wednesday afternoon
through Christmas Day. At this time...it looks like Central and
Southwest MT will see the brunt of this storm. At lower
elevations...there will be a swath of 3 to 5 inches of snow...with
around 8 to 10 inches in the mountains. It is too early to pin-point
the exact area that will see this heavier snowfall...but right now
that swath of heavier snow is forecasted along a Helena to Bozeman
line. This line of heavier snow could shift a bit over the next few
days as later model runs get a better handle on the storm track.
Brusda

&&

.AVIATION...
UPDATED 1138Z.
Weak high pressure will generally keep the airmass dry today. To the
west, a low pressure shortwave over the West Coast will approach the
Rockies by this evening and the chance of precipitation will
increase across Central and Southwest Montana...with the best
chances over Southwest Montana. Local MVFR conditions are expected
tonight along with mountain obscuration. VFR conditions will prevail
Saturday.


Even though an upper-level ridge of high pressure will move over the
Northern Rockies tonight, Pacific moisture moving over the ridge
will keep SCT to BKN cigs with mountain obscuration likely through
Friday. TAF locations will remain dry through Friday afternoon
before the next weather system moves into the area, however light
snow showers are expected over the mountains tonight and Friday.
Southwest winds will be less than 15 kts over the plains tonight as
the ridge continues to build, but southwest winds will increase at
KCTB and KGTF again on Friday afternoon. Conditions will begin to
deteriorate from west to east on Friday afternoon and evening with
light snow developing at KBZN and KHLN by 02z Saturday. Have added
VCSH to KHVR, KGTF and KLWT by 04z Saturday. MLV

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  42  28  40  34 /  10  30  10  20
CTB  40  26  36  29 /  10  20   0  20
HLN  37  22  36  28 /  10  40  10  40
BZN  35  18  33  27 /  10  40  10  50
WEY  33  20  32  27 /  50  50  40  70
DLN  38  20  35  31 /  10  40  10  50
HVR  39  26  39  26 /  10  30  10  20
LWT  44  25  41  29 /  10  30  10  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls








000
FXUS65 KTFX 191138
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
438 AM MST Fri Dec 19 2014

.DISCUSSION...

Tonight through Sunday...A high pressure ridge will be over the
Rockies and moving over the zones during the day. To the west, a low
pressure trof will move over the West Coast during the day. Decent
dynamics develop as the trof crosses the Rockies although this will
be a fast-moving feature and little time for development of weather.
Best lift with this system will be Friday night over the southwest
zones. However, a chance for mixed snow and rain are expected
tonight over central and northern portions of the CWA. Will include
some freezing rain in the grids after midnight as the surface
conditions cool. The upper level trof will move over the zones by
early Saturday and weak ridging will be in place to the west and
moving across the zones during the day. A strong jet at upper levels
will be over the Pacific Northwest Saturday and spread east over the
zones Saturday night and Sunday. Mid-level winds will increase to
45+ kts Saturday night and Sunday. This will bring very strong winds
across the Rockies and adjacent plains. Some stability develops at
lower levels after midnight and the will bring the best chance for
strong winds spreading east. Currently, have some gusts above
58 mph over the Rockies but because of uncertainty will hold off on
statements. Some strong winds as well at higher elevations will also
occur across Southwest Montana by Sunday and will have to be
monitored. Widespread precipitation will develop with the approach
of a shortwave associated with these strong winds Saturday night
and, once again, the chance of freezing rain will develop and will
be included in the grids after midnight into Sunday morning. Some
higher snow accumulations are expected at higher elevations in the
southwest zones but widespread heavy snow is not expected. Zelzer

Sunday night through Friday...A rather active weather pattern is
setting up for much of the region for next week. At this time...we
are not expecting significant snow storms...but rather several
accumulating snowfall events that will cause impacts for daily
commuters and travelers. Through much of the extended...the GFS13
and EC are in pretty good agreement. Temperatures will be near/a bit
above normal Monday and into Tuesday...but then begin to turn colder
Wednesday through Friday. For now I used a lower blend of the colder
models for temperatures...but temperatures could be several degrees
colder than currently forecasted should the snowpack become a bit
deeper than expected. Additionally...there is the potential for
another high wind event over portions of North Central MT on Tuesday.

In terms of precipitation...Southwest MT will continue to see
precipitation Sunday night and into Monday morning...with scattered
showers over North Central MT. The precipitation becomes fairly
light and scattered Monday night through Tuesday. Then a fairly
strong storm system will move through the region Wednesday afternoon
through Christmas Day. At this time...it looks like Central and
Southwest MT will see the brunt of this storm. At lower
elevations...there will be a swath of 3 to 5 inches of snow...with
around 8 to 10 inches in the mountains. It is too early to pin-point
the exact area that will see this heavier snowfall...but right now
that swath of heavier snow is forecasted along a Helena to Bozeman
line. This line of heavier snow could shift a bit over the next few
days as later model runs get a better handle on the storm track.
Brusda

&&

.AVIATION...
UPDATED 1138Z.
Weak high pressure will generally keep the airmass dry today. To the
west, a low pressure shortwave over the West Coast will approach the
Rockies by this evening and the chance of precipitation will
increase across Central and Southwest Montana...with the best
chances over Southwest Montana. Local MVFR conditions are expected
tonight along with mountain obscuration. VFR conditions will prevail
Saturday.


Even though an upper-level ridge of high pressure will move over the
Northern Rockies tonight, Pacific moisture moving over the ridge
will keep SCT to BKN cigs with mountain obscuration likely through
Friday. TAF locations will remain dry through Friday afternoon
before the next weather system moves into the area, however light
snow showers are expected over the mountains tonight and Friday.
Southwest winds will be less than 15 kts over the plains tonight as
the ridge continues to build, but southwest winds will increase at
KCTB and KGTF again on Friday afternoon. Conditions will begin to
deteriorate from west to east on Friday afternoon and evening with
light snow developing at KBZN and KHLN by 02z Saturday. Have added
VCSH to KHVR, KGTF and KLWT by 04z Saturday. MLV

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  42  28  40  34 /  10  30  10  20
CTB  40  26  36  29 /  10  20   0  20
HLN  37  22  36  28 /  10  40  10  40
BZN  35  18  33  27 /  10  40  10  50
WEY  33  20  32  27 /  50  50  40  70
DLN  38  20  35  31 /  10  40  10  50
HVR  39  26  39  26 /  10  30  10  20
LWT  44  25  41  29 /  10  30  10  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls









000
FXUS65 KTFX 191048
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
348 AM MST Fri Dec 19 2014

.DISCUSSION...

Tonight through Sunday...A high pressure ridge will be over the
Rockies and moving over the zones during the day. To the west, a low
pressure trof will move over the West Coast during the day. Decent
dynamics develop as the trof crosses the Rockies although this will
be a fast-moving feature and little time for development of weather.
Best lift with this system will be Friday night over the southwest
zones. However, a chance for mixed snow and rain are expected
tonight over central and northern portions of the CWA. Will include
some freezing rain in the grids after midnight as the surface
conditions cool. The upper level trof will move over the zones by
early Saturday and weak ridging will be in place to the west and
moving across the zones during the day. A strong jet at upper levels
will be over the Pacific Northwest Saturday and spread east over the
zones Saturday night and Sunday. Mid-level winds will increase to
45+ kts Saturday night and Sunday. This will bring very strong winds
across the Rockies and adjacent plains. Some stability develops at
lower levels after midnight and the will bring the best chance for
strong winds spreading east. Currently, have some gusts above
58 mph over the Rockies but because of uncertainty will hold off on
statements. Some strong winds as well at higher elevations will also
occur across Southwest Montana by Sunday and will have to be
monitored. Widespread precipitation will develop with the approach
of a shortwave associated with these strong winds Saturday night
and, once again, the chance of freezing rain will develop and will
be included in the grids after midnight into Sunday morning. Some
higher snow accumulations are expected at higher elevations in the
southwest zones but widespread heavy snow is not expected. Zelzer

Sunday night through Friday...A rather active weather pattern is
setting up for much of the region for next week. At this time...we
are not expecting significant snow storms...but rather several
accumulating snowfall events that will cause impacts for daily
commuters and travelers. Through much of the extended...the GFS13
and EC are in pretty good agreement. Temperatures will be near/a bit
above normal Monday and into Tuesday...but then begin to turn colder
Wednesday through Friday. For now I used a lower blend of the colder
models for temperatures...but temperatures could be several degrees
colder than currently forecasted should the snowpack become a bit
deeper than expected. Additionally...there is the potential for
another high wind event over portions of North Central MT on Tuesday.

In terms of precipitation...Southwest MT will continue to see
precipitation Sunday night and into Monday morning...with scattered
showers over North Central MT. The precipitation becomes fairly
light and scattered Monday night through Tuesday. Then a fairly
strong storm system will move through the region Wednesday afternoon
through Christmas Day. At this time...it looks like Central and
Southwest MT will see the brunt of this storm. At lower
elevations...there will be a swath of 3 to 5 inches of snow...with
around 8 to 10 inches in the mountains. It is too early to pin-point
the exact area that will see this heavier snowfall...but right now
that swath of heavier snow is forecasted along a Helena to Bozeman
line. This line of heavier snow could shift a bit over the next few
days as later model runs get a better handle on the storm track.
Brusda

&&

.AVIATION...
UPDATED 0600Z.
Even though an upper-level ridge of high pressure will move over the
Northern Rockies tonight, Pacific moisture moving over the ridge
will keep SCT to BKN cigs with mountain obscuration likely through
Friday. TAF locations will remain dry through Friday afternoon
before the next weather system moves into the area, however light
snow showers are expected over the mountains tonight and Friday.
Southwest winds will be less than 15 kts over the plains tonight as
the ridge continues to build, but southwest winds will increase at
KCTB and KGTF again on Friday afternoon. Conditions will begin to
deteriorate from west to east on Friday afternoon and evening with
light snow developing at KBZN and KHLN by 02z Saturday. Have added
VCSH to KHVR, KGTF and KLWT by 04z Saturday. MLV

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  42  28  40  34 /  10  30  10  20
CTB  40  26  36  29 /  10  20   0  20
HLN  37  22  36  28 /  10  40  10  40
BZN  35  18  33  27 /  10  40  10  50
WEY  33  20  32  27 /  50  50  40  70
DLN  38  20  35  31 /  10  40  10  50
HVR  39  26  39  26 /  10  30  10  20
LWT  44  25  41  29 /  10  30  10  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 191048
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
348 AM MST Fri Dec 19 2014

.DISCUSSION...

Tonight through Sunday...A high pressure ridge will be over the
Rockies and moving over the zones during the day. To the west, a low
pressure trof will move over the West Coast during the day. Decent
dynamics develop as the trof crosses the Rockies although this will
be a fast-moving feature and little time for development of weather.
Best lift with this system will be Friday night over the southwest
zones. However, a chance for mixed snow and rain are expected
tonight over central and northern portions of the CWA. Will include
some freezing rain in the grids after midnight as the surface
conditions cool. The upper level trof will move over the zones by
early Saturday and weak ridging will be in place to the west and
moving across the zones during the day. A strong jet at upper levels
will be over the Pacific Northwest Saturday and spread east over the
zones Saturday night and Sunday. Mid-level winds will increase to
45+ kts Saturday night and Sunday. This will bring very strong winds
across the Rockies and adjacent plains. Some stability develops at
lower levels after midnight and the will bring the best chance for
strong winds spreading east. Currently, have some gusts above
58 mph over the Rockies but because of uncertainty will hold off on
statements. Some strong winds as well at higher elevations will also
occur across Southwest Montana by Sunday and will have to be
monitored. Widespread precipitation will develop with the approach
of a shortwave associated with these strong winds Saturday night
and, once again, the chance of freezing rain will develop and will
be included in the grids after midnight into Sunday morning. Some
higher snow accumulations are expected at higher elevations in the
southwest zones but widespread heavy snow is not expected. Zelzer

Sunday night through Friday...A rather active weather pattern is
setting up for much of the region for next week. At this time...we
are not expecting significant snow storms...but rather several
accumulating snowfall events that will cause impacts for daily
commuters and travelers. Through much of the extended...the GFS13
and EC are in pretty good agreement. Temperatures will be near/a bit
above normal Monday and into Tuesday...but then begin to turn colder
Wednesday through Friday. For now I used a lower blend of the colder
models for temperatures...but temperatures could be several degrees
colder than currently forecasted should the snowpack become a bit
deeper than expected. Additionally...there is the potential for
another high wind event over portions of North Central MT on Tuesday.

In terms of precipitation...Southwest MT will continue to see
precipitation Sunday night and into Monday morning...with scattered
showers over North Central MT. The precipitation becomes fairly
light and scattered Monday night through Tuesday. Then a fairly
strong storm system will move through the region Wednesday afternoon
through Christmas Day. At this time...it looks like Central and
Southwest MT will see the brunt of this storm. At lower
elevations...there will be a swath of 3 to 5 inches of snow...with
around 8 to 10 inches in the mountains. It is too early to pin-point
the exact area that will see this heavier snowfall...but right now
that swath of heavier snow is forecasted along a Helena to Bozeman
line. This line of heavier snow could shift a bit over the next few
days as later model runs get a better handle on the storm track.
Brusda

&&

.AVIATION...
UPDATED 0600Z.
Even though an upper-level ridge of high pressure will move over the
Northern Rockies tonight, Pacific moisture moving over the ridge
will keep SCT to BKN cigs with mountain obscuration likely through
Friday. TAF locations will remain dry through Friday afternoon
before the next weather system moves into the area, however light
snow showers are expected over the mountains tonight and Friday.
Southwest winds will be less than 15 kts over the plains tonight as
the ridge continues to build, but southwest winds will increase at
KCTB and KGTF again on Friday afternoon. Conditions will begin to
deteriorate from west to east on Friday afternoon and evening with
light snow developing at KBZN and KHLN by 02z Saturday. Have added
VCSH to KHVR, KGTF and KLWT by 04z Saturday. MLV

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  42  28  40  34 /  10  30  10  20
CTB  40  26  36  29 /  10  20   0  20
HLN  37  22  36  28 /  10  40  10  40
BZN  35  18  33  27 /  10  40  10  50
WEY  33  20  32  27 /  50  50  40  70
DLN  38  20  35  31 /  10  40  10  50
HVR  39  26  39  26 /  10  30  10  20
LWT  44  25  41  29 /  10  30  10  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 190537
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1035 PM MST Thu Dec 18 2014

Updated Aviation

.UPDATE...
Quiet weather conditions across the region this evening. A pair of
weak disturbances, one stretching from near Havre to Billings and
the second just moving into southwest MT, are producing increased
cloud cover and isolated flurries/light snow in those areas. Only
other weather item of note is patchy fog in parts of the Milk
River valley as noted by the current observation in Chinook of
1/4 mile visibility. Not expecting any broad areas of dense fog
tonight, thanks in part to more steady southwest surface winds, so
no fog advisories are in effect for the first time in the past
several nights. Only forecast adjustments were to add the mention
of flurries in southern sections of Meagher/Judith Basin/Fergus
counties and the fog in Hill/Blaine counties.
Waranauskas

&&

.AVIATION...
UPDATED 0600Z.
Even though an upper-level ridge of high pressure will move over the
Northern Rockies tonight, Pacific moisture moving over the ridge
will keep SCT to BKN cigs with mountain obscuration likely through
Friday. TAF locations will remain dry through Friday afternoon
before the next weather system moves into the area, however light
snow showers are expected over the mountains tonight and Friday.
Southwest winds will be less than 15 kts over the plains tonight as
the ridge continues to build, but southwest winds will increase at
KCTB and KGTF again on Friday afternoon. Conditions will begin to
deteriorate from west to east on Friday afternoon and evening with
light snow developing at KBZN and KHLN by 02z Saturday. Have added
VCSH to KHVR, KGTF and KLWT by 04z Saturday. MLV

&&

.PREV DISCUSSION...
/ISSUED 440 PM MST Thu Dec 18 2014/
Tonight through Saturday...The freezing fog advisory for northern
Blaine and northern Hill Counties has been cancelled as visibilities
have generally improved.A couple of weather disturbances aloft
will affect the forecast area during the period. The first one
will move through this evening. It looks like the only areas that
could see some light snow are the Little Belt Mountains..mountains
near the Idaho border..and mountains of the Rocky Mountain Front.
The next weather disturbance will move through Friday night. This
disturbance will have more moisture with it so mountains will
likely see a period of snow while there will be a chance of
precipitation for the lower elevations. This precipitation will
likely be a mix of types with rain and snow most prevalent but
there will also be a small threat of freezing rain over the
eastern plains. If freezing rain should occur do not think it will
last very long or be very widespread. Then Saturday westerly flow
aloft will develop and expect gusty southwest winds over the east
slopes of the Rocky Mountains. Blank

Saturday Night through Thursday...Through Monday, an upper level
high pressure ridge will strengthen over the eastern Pacific Ocean
and an upper level low pressure trough will deepen over central
Canada and the northern CONUS plains. The resulting strong
northwesterly flow aloft will bring increasing westerly surface
winds to the forecast area. Although forecast models are not quite
as strong with these winds as they have been the last couple of
nights, there is still a chance for High Wind criteria winds along
the Rocky Mountain Front and over some ridge tops. Will continue to
monitor this for potential High Wind highlights. This increasing
flow aloft will also bring warm and moist Pacific air and a weak
disturbance into the area. The main impact from this will be at
least a rain/snow mix in the mountains, if not mostly rain, while
the plains and valleys will have less of a chance of precipitation.
This could be a concern in the mountains with regard to rain
possibly falling on snowpack. Will monitor this situation for
potential hydrologic highlights. With the warm air aloft moving over
cooler air at the surface over the plains of north central Montana
Saturday night into Sunday morning, have included a slight chance of
freezing drizzle there. The westerly downslope winds will quickly
spread east across the area during the day on Sunday, warming
temperatures well into the 40s by afternoon. Temperatures will
remain similarly mild through Monday. As the disturbance exits the
area Monday night, the chance for precipitation will be limited to
the mountains into Tuesday. However, a weak cold front will move
south through the area on Tuesday, cooling temperatures to near
seasonal averages. As was mentioned yesterday, a cold and moist
weather system will move southeast from the Gulf of Alaska and into
the northern Rockies for Wednesday (Christmas Eve Day) into Thursday
(Christmas Day). There is still a good chance of precipitation with
this system across the area, but forecast models are trending a bit
farther south with the heaviest precipitation, focusing it more over
southwest Montana than central Montana. Have therefore made this
adjustment to the forecast. There is still a good indication that
temperatures will cool significantly below normal through this
period, for widespread light snow. Will continue to monitor the
progress of this system for potential winter weather highlights, as
this system will likely negatively impact holiday travel. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  27  41  28  40 /  10  10  20   0
CTB  24  39  27  37 /  10  10   0  10
HLN  20  36  22  36 /  10  20  40  10
BZN  17  33  19  34 /   0  10  50  10
WEY  20  33  21  32 /  40  50  60  50
DLN  20  38  21  36 /   0  20  40  10
HVR  21  39  27  40 /  10  10  20   0
LWT  25  45  26  42 /   0   0  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls








000
FXUS65 KTFX 190537
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1035 PM MST Thu Dec 18 2014

Updated Aviation

.UPDATE...
Quiet weather conditions across the region this evening. A pair of
weak disturbances, one stretching from near Havre to Billings and
the second just moving into southwest MT, are producing increased
cloud cover and isolated flurries/light snow in those areas. Only
other weather item of note is patchy fog in parts of the Milk
River valley as noted by the current observation in Chinook of
1/4 mile visibility. Not expecting any broad areas of dense fog
tonight, thanks in part to more steady southwest surface winds, so
no fog advisories are in effect for the first time in the past
several nights. Only forecast adjustments were to add the mention
of flurries in southern sections of Meagher/Judith Basin/Fergus
counties and the fog in Hill/Blaine counties.
Waranauskas

&&

.AVIATION...
UPDATED 0600Z.
Even though an upper-level ridge of high pressure will move over the
Northern Rockies tonight, Pacific moisture moving over the ridge
will keep SCT to BKN cigs with mountain obscuration likely through
Friday. TAF locations will remain dry through Friday afternoon
before the next weather system moves into the area, however light
snow showers are expected over the mountains tonight and Friday.
Southwest winds will be less than 15 kts over the plains tonight as
the ridge continues to build, but southwest winds will increase at
KCTB and KGTF again on Friday afternoon. Conditions will begin to
deteriorate from west to east on Friday afternoon and evening with
light snow developing at KBZN and KHLN by 02z Saturday. Have added
VCSH to KHVR, KGTF and KLWT by 04z Saturday. MLV

&&

.PREV DISCUSSION...
/ISSUED 440 PM MST Thu Dec 18 2014/
Tonight through Saturday...The freezing fog advisory for northern
Blaine and northern Hill Counties has been cancelled as visibilities
have generally improved.A couple of weather disturbances aloft
will affect the forecast area during the period. The first one
will move through this evening. It looks like the only areas that
could see some light snow are the Little Belt Mountains..mountains
near the Idaho border..and mountains of the Rocky Mountain Front.
The next weather disturbance will move through Friday night. This
disturbance will have more moisture with it so mountains will
likely see a period of snow while there will be a chance of
precipitation for the lower elevations. This precipitation will
likely be a mix of types with rain and snow most prevalent but
there will also be a small threat of freezing rain over the
eastern plains. If freezing rain should occur do not think it will
last very long or be very widespread. Then Saturday westerly flow
aloft will develop and expect gusty southwest winds over the east
slopes of the Rocky Mountains. Blank

Saturday Night through Thursday...Through Monday, an upper level
high pressure ridge will strengthen over the eastern Pacific Ocean
and an upper level low pressure trough will deepen over central
Canada and the northern CONUS plains. The resulting strong
northwesterly flow aloft will bring increasing westerly surface
winds to the forecast area. Although forecast models are not quite
as strong with these winds as they have been the last couple of
nights, there is still a chance for High Wind criteria winds along
the Rocky Mountain Front and over some ridge tops. Will continue to
monitor this for potential High Wind highlights. This increasing
flow aloft will also bring warm and moist Pacific air and a weak
disturbance into the area. The main impact from this will be at
least a rain/snow mix in the mountains, if not mostly rain, while
the plains and valleys will have less of a chance of precipitation.
This could be a concern in the mountains with regard to rain
possibly falling on snowpack. Will monitor this situation for
potential hydrologic highlights. With the warm air aloft moving over
cooler air at the surface over the plains of north central Montana
Saturday night into Sunday morning, have included a slight chance of
freezing drizzle there. The westerly downslope winds will quickly
spread east across the area during the day on Sunday, warming
temperatures well into the 40s by afternoon. Temperatures will
remain similarly mild through Monday. As the disturbance exits the
area Monday night, the chance for precipitation will be limited to
the mountains into Tuesday. However, a weak cold front will move
south through the area on Tuesday, cooling temperatures to near
seasonal averages. As was mentioned yesterday, a cold and moist
weather system will move southeast from the Gulf of Alaska and into
the northern Rockies for Wednesday (Christmas Eve Day) into Thursday
(Christmas Day). There is still a good chance of precipitation with
this system across the area, but forecast models are trending a bit
farther south with the heaviest precipitation, focusing it more over
southwest Montana than central Montana. Have therefore made this
adjustment to the forecast. There is still a good indication that
temperatures will cool significantly below normal through this
period, for widespread light snow. Will continue to monitor the
progress of this system for potential winter weather highlights, as
this system will likely negatively impact holiday travel. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  27  41  28  40 /  10  10  20   0
CTB  24  39  27  37 /  10  10   0  10
HLN  20  36  22  36 /  10  20  40  10
BZN  17  33  19  34 /   0  10  50  10
WEY  20  33  21  32 /  40  50  60  50
DLN  20  38  21  36 /   0  20  40  10
HVR  21  39  27  40 /  10  10  20   0
LWT  25  45  26  42 /   0   0  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls









000
FXUS65 KTFX 190347
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
847 PM MST Thu Dec 18 2014

.UPDATE...
Quiet weather conditions across the region this evening. A pair of
weak disturbances, one stretching from near Havre to Billings and
the second just moving into southwest MT, are producing increased
cloud cover and isolated flurries/light snow in those areas. Only
other weather item of note is patchy fog in parts of the Milk
River valley as noted by the current observation in Chinook of
1/4 mile visibility. Not expecting any broad areas of dense fog
tonight, thanks in part to more steady southwest surface winds, so
no fog advisories are in effect for the first time in the past
several nights. Only forecast adjustments were to add the mention
of flurries in southern sections of Meagher/Judith Basin/Fergus
counties and the fog in Hill/Blaine counties.
Waranauskas

&&

.AVIATION...
UPDATED 2340Z.
Even though an upper-level ridge of high pressure will build over
the Northern Rockies tonight, Pacific moisture moving over the ridge
will keep SCT to BKN cigs with mountain obscuration likely through
Friday. TAF locations will remain dry, however light snow showers
are expected over the mountains, thus have added VCSH to KBZN and
KHLN. Patchy fog is also possible overnight at KHLN, but confidence
is low given the expected mid-level cloud cover. Southwest winds
will decrease over the plains this evening as the ridge continues to
build. VFR conditions will prevail at all terminals through the
forecast period with the exception of KHLN if fog develops. MLV

&&

.PREV DISCUSSION...
/ISSUED 440 PM MST Thu Dec 18 2014/
Tonight through Saturday...The freezing fog advisory for northern
Blaine and northern Hill Counties has been cancelled as visibilities
have generally improved.A couple of weather disturbances aloft
will affect the forecast area during the period. The first one
will move through this evening. It looks like the only areas that
could see some light snow are the Little Belt Mountains..mountains
near the Idaho border..and mountains of the Rocky Mountain Front.
The next weather disturbance will move through Friday night. This
disturbance will have more moisture with it so mountains will
likely see a period of snow while there will be a chance of
precipitation for the lower elevations. This precipitation will
likely be a mix of types with rain and snow most prevalent but
there will also be a small threat of freezing rain over the
eastern plains. If freezing rain should occur do not think it will
last very long or be very widespread. Then Saturday westerly flow
aloft will develop and expect gusty southwest winds over the east
slopes of the Rocky Mountains. Blank

Saturday Night through Thursday...Through Monday, an upper level
high pressure ridge will strengthen over the eastern Pacific Ocean
and an upper level low pressure trough will deepen over central
Canada and the northern CONUS plains. The resulting strong
northwesterly flow aloft will bring increasing westerly surface
winds to the forecast area. Although forecast models are not quite
as strong with these winds as they have been the last couple of
nights, there is still a chance for High Wind criteria winds along
the Rocky Mountain Front and over some ridge tops. Will continue to
monitor this for potential High Wind highlights. This increasing
flow aloft will also bring warm and moist Pacific air and a weak
disturbance into the area. The main impact from this will be at
least a rain/snow mix in the mountains, if not mostly rain, while
the plains and valleys will have less of a chance of precipitation.
This could be a concern in the mountains with regard to rain
possibly falling on snowpack. Will monitor this situation for
potential hydrologic highlights. With the warm air aloft moving over
cooler air at the surface over the plains of north central Montana
Saturday night into Sunday morning, have included a slight chance of
freezing drizzle there. The westerly downslope winds will quickly
spread east across the area during the day on Sunday, warming
temperatures well into the 40s by afternoon. Temperatures will
remain similarly mild through Monday. As the disturbance exits the
area Monday night, the chance for precipitation will be limited to
the mountains into Tuesday. However, a weak cold front will move
south through the area on Tuesday, cooling temperatures to near
seasonal averages. As was mentioned yesterday, a cold and moist
weather system will move southeast from the Gulf of Alaska and into
the northern Rockies for Wednesday (Christmas Eve Day) into Thursday
(Christmas Day). There is still a good chance of precipitation with
this system across the area, but forecast models are trending a bit
farther south with the heaviest precipitation, focusing it more over
southwest Montana than central Montana. Have therefore made this
adjustment to the forecast. There is still a good indication that
temperatures will cool significantly below normal through this
period, for widespread light snow. Will continue to monitor the
progress of this system for potential winter weather highlights, as
this system will likely negatively impact holiday travel. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  27  41  28  40 /  10  10  20   0
CTB  24  39  27  37 /  10  10   0  10
HLN  20  36  22  36 /  10  20  40  10
BZN  17  33  19  34 /   0  10  50  10
WEY  20  33  21  32 /  40  50  60  50
DLN  20  38  21  36 /   0  20  40  10
HVR  21  39  27  40 /  10  10  20   0
LWT  25  45  26  42 /   0   0  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 190347
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
847 PM MST Thu Dec 18 2014

.UPDATE...
Quiet weather conditions across the region this evening. A pair of
weak disturbances, one stretching from near Havre to Billings and
the second just moving into southwest MT, are producing increased
cloud cover and isolated flurries/light snow in those areas. Only
other weather item of note is patchy fog in parts of the Milk
River valley as noted by the current observation in Chinook of
1/4 mile visibility. Not expecting any broad areas of dense fog
tonight, thanks in part to more steady southwest surface winds, so
no fog advisories are in effect for the first time in the past
several nights. Only forecast adjustments were to add the mention
of flurries in southern sections of Meagher/Judith Basin/Fergus
counties and the fog in Hill/Blaine counties.
Waranauskas

&&

.AVIATION...
UPDATED 2340Z.
Even though an upper-level ridge of high pressure will build over
the Northern Rockies tonight, Pacific moisture moving over the ridge
will keep SCT to BKN cigs with mountain obscuration likely through
Friday. TAF locations will remain dry, however light snow showers
are expected over the mountains, thus have added VCSH to KBZN and
KHLN. Patchy fog is also possible overnight at KHLN, but confidence
is low given the expected mid-level cloud cover. Southwest winds
will decrease over the plains this evening as the ridge continues to
build. VFR conditions will prevail at all terminals through the
forecast period with the exception of KHLN if fog develops. MLV

&&

.PREV DISCUSSION...
/ISSUED 440 PM MST Thu Dec 18 2014/
Tonight through Saturday...The freezing fog advisory for northern
Blaine and northern Hill Counties has been cancelled as visibilities
have generally improved.A couple of weather disturbances aloft
will affect the forecast area during the period. The first one
will move through this evening. It looks like the only areas that
could see some light snow are the Little Belt Mountains..mountains
near the Idaho border..and mountains of the Rocky Mountain Front.
The next weather disturbance will move through Friday night. This
disturbance will have more moisture with it so mountains will
likely see a period of snow while there will be a chance of
precipitation for the lower elevations. This precipitation will
likely be a mix of types with rain and snow most prevalent but
there will also be a small threat of freezing rain over the
eastern plains. If freezing rain should occur do not think it will
last very long or be very widespread. Then Saturday westerly flow
aloft will develop and expect gusty southwest winds over the east
slopes of the Rocky Mountains. Blank

Saturday Night through Thursday...Through Monday, an upper level
high pressure ridge will strengthen over the eastern Pacific Ocean
and an upper level low pressure trough will deepen over central
Canada and the northern CONUS plains. The resulting strong
northwesterly flow aloft will bring increasing westerly surface
winds to the forecast area. Although forecast models are not quite
as strong with these winds as they have been the last couple of
nights, there is still a chance for High Wind criteria winds along
the Rocky Mountain Front and over some ridge tops. Will continue to
monitor this for potential High Wind highlights. This increasing
flow aloft will also bring warm and moist Pacific air and a weak
disturbance into the area. The main impact from this will be at
least a rain/snow mix in the mountains, if not mostly rain, while
the plains and valleys will have less of a chance of precipitation.
This could be a concern in the mountains with regard to rain
possibly falling on snowpack. Will monitor this situation for
potential hydrologic highlights. With the warm air aloft moving over
cooler air at the surface over the plains of north central Montana
Saturday night into Sunday morning, have included a slight chance of
freezing drizzle there. The westerly downslope winds will quickly
spread east across the area during the day on Sunday, warming
temperatures well into the 40s by afternoon. Temperatures will
remain similarly mild through Monday. As the disturbance exits the
area Monday night, the chance for precipitation will be limited to
the mountains into Tuesday. However, a weak cold front will move
south through the area on Tuesday, cooling temperatures to near
seasonal averages. As was mentioned yesterday, a cold and moist
weather system will move southeast from the Gulf of Alaska and into
the northern Rockies for Wednesday (Christmas Eve Day) into Thursday
(Christmas Day). There is still a good chance of precipitation with
this system across the area, but forecast models are trending a bit
farther south with the heaviest precipitation, focusing it more over
southwest Montana than central Montana. Have therefore made this
adjustment to the forecast. There is still a good indication that
temperatures will cool significantly below normal through this
period, for widespread light snow. Will continue to monitor the
progress of this system for potential winter weather highlights, as
this system will likely negatively impact holiday travel. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  27  41  28  40 /  10  10  20   0
CTB  24  39  27  37 /  10  10   0  10
HLN  20  36  22  36 /  10  20  40  10
BZN  17  33  19  34 /   0  10  50  10
WEY  20  33  21  32 /  40  50  60  50
DLN  20  38  21  36 /   0  20  40  10
HVR  21  39  27  40 /  10  10  20   0
LWT  25  45  26  42 /   0   0  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 190347
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
847 PM MST Thu Dec 18 2014

.UPDATE...
Quiet weather conditions across the region this evening. A pair of
weak disturbances, one stretching from near Havre to Billings and
the second just moving into southwest MT, are producing increased
cloud cover and isolated flurries/light snow in those areas. Only
other weather item of note is patchy fog in parts of the Milk
River valley as noted by the current observation in Chinook of
1/4 mile visibility. Not expecting any broad areas of dense fog
tonight, thanks in part to more steady southwest surface winds, so
no fog advisories are in effect for the first time in the past
several nights. Only forecast adjustments were to add the mention
of flurries in southern sections of Meagher/Judith Basin/Fergus
counties and the fog in Hill/Blaine counties.
Waranauskas

&&

.AVIATION...
UPDATED 2340Z.
Even though an upper-level ridge of high pressure will build over
the Northern Rockies tonight, Pacific moisture moving over the ridge
will keep SCT to BKN cigs with mountain obscuration likely through
Friday. TAF locations will remain dry, however light snow showers
are expected over the mountains, thus have added VCSH to KBZN and
KHLN. Patchy fog is also possible overnight at KHLN, but confidence
is low given the expected mid-level cloud cover. Southwest winds
will decrease over the plains this evening as the ridge continues to
build. VFR conditions will prevail at all terminals through the
forecast period with the exception of KHLN if fog develops. MLV

&&

.PREV DISCUSSION...
/ISSUED 440 PM MST Thu Dec 18 2014/
Tonight through Saturday...The freezing fog advisory for northern
Blaine and northern Hill Counties has been cancelled as visibilities
have generally improved.A couple of weather disturbances aloft
will affect the forecast area during the period. The first one
will move through this evening. It looks like the only areas that
could see some light snow are the Little Belt Mountains..mountains
near the Idaho border..and mountains of the Rocky Mountain Front.
The next weather disturbance will move through Friday night. This
disturbance will have more moisture with it so mountains will
likely see a period of snow while there will be a chance of
precipitation for the lower elevations. This precipitation will
likely be a mix of types with rain and snow most prevalent but
there will also be a small threat of freezing rain over the
eastern plains. If freezing rain should occur do not think it will
last very long or be very widespread. Then Saturday westerly flow
aloft will develop and expect gusty southwest winds over the east
slopes of the Rocky Mountains. Blank

Saturday Night through Thursday...Through Monday, an upper level
high pressure ridge will strengthen over the eastern Pacific Ocean
and an upper level low pressure trough will deepen over central
Canada and the northern CONUS plains. The resulting strong
northwesterly flow aloft will bring increasing westerly surface
winds to the forecast area. Although forecast models are not quite
as strong with these winds as they have been the last couple of
nights, there is still a chance for High Wind criteria winds along
the Rocky Mountain Front and over some ridge tops. Will continue to
monitor this for potential High Wind highlights. This increasing
flow aloft will also bring warm and moist Pacific air and a weak
disturbance into the area. The main impact from this will be at
least a rain/snow mix in the mountains, if not mostly rain, while
the plains and valleys will have less of a chance of precipitation.
This could be a concern in the mountains with regard to rain
possibly falling on snowpack. Will monitor this situation for
potential hydrologic highlights. With the warm air aloft moving over
cooler air at the surface over the plains of north central Montana
Saturday night into Sunday morning, have included a slight chance of
freezing drizzle there. The westerly downslope winds will quickly
spread east across the area during the day on Sunday, warming
temperatures well into the 40s by afternoon. Temperatures will
remain similarly mild through Monday. As the disturbance exits the
area Monday night, the chance for precipitation will be limited to
the mountains into Tuesday. However, a weak cold front will move
south through the area on Tuesday, cooling temperatures to near
seasonal averages. As was mentioned yesterday, a cold and moist
weather system will move southeast from the Gulf of Alaska and into
the northern Rockies for Wednesday (Christmas Eve Day) into Thursday
(Christmas Day). There is still a good chance of precipitation with
this system across the area, but forecast models are trending a bit
farther south with the heaviest precipitation, focusing it more over
southwest Montana than central Montana. Have therefore made this
adjustment to the forecast. There is still a good indication that
temperatures will cool significantly below normal through this
period, for widespread light snow. Will continue to monitor the
progress of this system for potential winter weather highlights, as
this system will likely negatively impact holiday travel. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  27  41  28  40 /  10  10  20   0
CTB  24  39  27  37 /  10  10   0  10
HLN  20  36  22  36 /  10  20  40  10
BZN  17  33  19  34 /   0  10  50  10
WEY  20  33  21  32 /  40  50  60  50
DLN  20  38  21  36 /   0  20  40  10
HVR  21  39  27  40 /  10  10  20   0
LWT  25  45  26  42 /   0   0  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 182340
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
440 PM MST Thu Dec 18 2014

Updated Aviation

.DISCUSSION...
Tonight through Saturday...The freezing fog advisory for northern
Blaine and northern Hill Counties has been cancelled as visibilities
have generally improved.A couple of weather disturbances aloft
will affect the forecast area during the period. The first one
will move through this evening. It looks like the only areas that
could see some light snow are the Little Belt Mountains..mountains
near the Idaho border..and mountains of the Rocky Mountain Front.
The next weather disturbance will move through Friday night. This
disturbance will have more moisture with it so mountains will
likely see a period of snow while there will be a chance of
precipitation for the lower elevations. This precipitation will
likely be a mix of types with rain and snow most prevalent but
there will also be a small threat of freezing rain over the
eastern plains. If freezing rain should occur do not think it will
last very long or be very widespread. Then Saturday westerly flow
aloft will develop and expect gusty southwest winds over the east
slopes of the Rocky Mountains. Blank

Saturday Night through Thursday...Through Monday, an upper level
high pressure ridge will strengthen over the eastern Pacific Ocean
and an upper level low pressure trough will deepen over central
Canada and the northern CONUS plains. The resulting strong
northwesterly flow aloft will bring increasing westerly surface
winds to the forecast area. Although forecast models are not quite
as strong with these winds as they have been the last couple of
nights, there is still a chance for High Wind criteria winds along
the Rocky Mountain Front and over some ridge tops. Will continue to
monitor this for potential High Wind highlights. This increasing
flow aloft will also bring warm and moist Pacific air and a weak
disturbance into the area. The main impact from this will be at
least a rain/snow mix in the mountains, if not mostly rain, while
the plains and valleys will have less of a chance of precipitation.
This could be a concern in the mountains with regard to rain
possibly falling on snowpack. Will monitor this situation for
potential hydrologic highlights. With the warm air aloft moving over
cooler air at the surface over the plains of north central Montana
Saturday night into Sunday morning, have included a slight chance of
freezing drizzle there. The westerly downslope winds will quickly
spread east across the area during the day on Sunday, warming
temperatures well into the 40s by afternoon. Temperatures will
remain similarly mild through Monday. As the disturbance exits the
area Monday night, the chance for precipitation will be limited to
the mountains into Tuesday. However, a weak cold front will move
south through the area on Tuesday, cooling temperatures to near
seasonal averages. As was mentioned yesterday, a cold and moist
weather system will move southeast from the Gulf of Alaska and into
the northern Rockies for Wednesday (Christmas Eve Day) into Thursday
(Christmas Day). There is still a good chance of precipitation with
this system across the area, but forecast models are trending a bit
farther south with the heaviest precipitation, focusing it more over
southwest Montana than central Montana. Have therefore made this
adjustment to the forecast. There is still a good indication that
temperatures will cool significantly below normal through this
period, for widespread light snow. Will continue to monitor the
progress of this system for potential winter weather highlights, as
this system will likely negatively impact holiday travel. Coulston

&&

.AVIATION...
UPDATED 2340Z.
Even though an upper-level ridge of high pressure will build over
the Northern Rockies tonight, Pacific moisture moving over the ridge
will keep SCT to BKN cigs with mountain obscuration likely through
Friday. TAF locations will remain dry, however light snow showers
are expected over the mountains, thus have added VCSH to KBZN and
KHLN. Patchy fog is also possible overnight at KHLN, but confidence
is low given the expected mid-level cloud cover. Southwest winds
will decrease over the plains this evening as the ridge continues to
build. VFR conditions will prevail at all terminals through the
forecast period with the exception of KHLN if fog develops. MLV

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  27  41  28  40 /  10  10  20   0
CTB  24  39  27  37 /  10  10   0  10
HLN  20  36  22  36 /  10  20  40  10
BZN  17  33  19  34 /   0  10  50  10
WEY  20  33  21  32 /  40  50  60  50
DLN  20  38  21  36 /   0  20  40  10
HVR  21  39  27  40 /  10  10  20   0
LWT  25  45  26  42 /   0   0  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls









000
FXUS65 KTFX 182340
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
440 PM MST Thu Dec 18 2014

Updated Aviation

.DISCUSSION...
Tonight through Saturday...The freezing fog advisory for northern
Blaine and northern Hill Counties has been cancelled as visibilities
have generally improved.A couple of weather disturbances aloft
will affect the forecast area during the period. The first one
will move through this evening. It looks like the only areas that
could see some light snow are the Little Belt Mountains..mountains
near the Idaho border..and mountains of the Rocky Mountain Front.
The next weather disturbance will move through Friday night. This
disturbance will have more moisture with it so mountains will
likely see a period of snow while there will be a chance of
precipitation for the lower elevations. This precipitation will
likely be a mix of types with rain and snow most prevalent but
there will also be a small threat of freezing rain over the
eastern plains. If freezing rain should occur do not think it will
last very long or be very widespread. Then Saturday westerly flow
aloft will develop and expect gusty southwest winds over the east
slopes of the Rocky Mountains. Blank

Saturday Night through Thursday...Through Monday, an upper level
high pressure ridge will strengthen over the eastern Pacific Ocean
and an upper level low pressure trough will deepen over central
Canada and the northern CONUS plains. The resulting strong
northwesterly flow aloft will bring increasing westerly surface
winds to the forecast area. Although forecast models are not quite
as strong with these winds as they have been the last couple of
nights, there is still a chance for High Wind criteria winds along
the Rocky Mountain Front and over some ridge tops. Will continue to
monitor this for potential High Wind highlights. This increasing
flow aloft will also bring warm and moist Pacific air and a weak
disturbance into the area. The main impact from this will be at
least a rain/snow mix in the mountains, if not mostly rain, while
the plains and valleys will have less of a chance of precipitation.
This could be a concern in the mountains with regard to rain
possibly falling on snowpack. Will monitor this situation for
potential hydrologic highlights. With the warm air aloft moving over
cooler air at the surface over the plains of north central Montana
Saturday night into Sunday morning, have included a slight chance of
freezing drizzle there. The westerly downslope winds will quickly
spread east across the area during the day on Sunday, warming
temperatures well into the 40s by afternoon. Temperatures will
remain similarly mild through Monday. As the disturbance exits the
area Monday night, the chance for precipitation will be limited to
the mountains into Tuesday. However, a weak cold front will move
south through the area on Tuesday, cooling temperatures to near
seasonal averages. As was mentioned yesterday, a cold and moist
weather system will move southeast from the Gulf of Alaska and into
the northern Rockies for Wednesday (Christmas Eve Day) into Thursday
(Christmas Day). There is still a good chance of precipitation with
this system across the area, but forecast models are trending a bit
farther south with the heaviest precipitation, focusing it more over
southwest Montana than central Montana. Have therefore made this
adjustment to the forecast. There is still a good indication that
temperatures will cool significantly below normal through this
period, for widespread light snow. Will continue to monitor the
progress of this system for potential winter weather highlights, as
this system will likely negatively impact holiday travel. Coulston

&&

.AVIATION...
UPDATED 2340Z.
Even though an upper-level ridge of high pressure will build over
the Northern Rockies tonight, Pacific moisture moving over the ridge
will keep SCT to BKN cigs with mountain obscuration likely through
Friday. TAF locations will remain dry, however light snow showers
are expected over the mountains, thus have added VCSH to KBZN and
KHLN. Patchy fog is also possible overnight at KHLN, but confidence
is low given the expected mid-level cloud cover. Southwest winds
will decrease over the plains this evening as the ridge continues to
build. VFR conditions will prevail at all terminals through the
forecast period with the exception of KHLN if fog develops. MLV

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  27  41  28  40 /  10  10  20   0
CTB  24  39  27  37 /  10  10   0  10
HLN  20  36  22  36 /  10  20  40  10
BZN  17  33  19  34 /   0  10  50  10
WEY  20  33  21  32 /  40  50  60  50
DLN  20  38  21  36 /   0  20  40  10
HVR  21  39  27  40 /  10  10  20   0
LWT  25  45  26  42 /   0   0  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls








000
FXUS65 KTFX 182143
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
243 PM MST Thu Dec 18 2014

.DISCUSSION...
Tonight through Saturday...The freezing fog advisory for northern
Blaine and northern Hill Counties has been cancelled as visibilities
have generally improved.A couple of weather disturbances aloft
will affect the forecast area during the period. The first one
will move through this evening. It looks like the only areas that
could see some light snow are the Little Belt Mountains..mountains
near the Idaho border..and mountains of the Rocky Mountain Front.
The next weather disturbance will move through Friday night. This
disturbance will have more moisture with it so mountains will
likely see a period of snow while there will be a chance of
precipitation for the lower elevations. This precipitation will
likely be a mix of types with rain and snow most prevalent but
there will also be a small threat of freezing rain over the
eastern plains. If freezing rain should occur do not think it will
last very long or be very widespread. Then Saturday westerly flow
aloft will develop and expect gusty southwest winds over the east
slopes of the Rocky Mountains. Blank

Saturday Night through Thursday...Through Monday, an upper level
high pressure ridge will strengthen over the eastern Pacific Ocean
and an upper level low pressure trough will deepen over central
Canada and the northern CONUS plains. The resulting strong
northwesterly flow aloft will bring increasing westerly surface
winds to the forecast area. Although forecast models are not quite
as strong with these winds as they have been the last couple of
nights, there is still a chance for High Wind criteria winds along
the Rocky Mountain Front and over some ridge tops. Will continue to
monitor this for potential High Wind highlights. This increasing
flow aloft will also bring warm and moist Pacific air and a weak
disturbance into the area. The main impact from this will be at
least a rain/snow mix in the mountains, if not mostly rain, while
the plains and valleys will have less of a chance of precipitation.
This could be a concern in the mountains with regard to rain
possibly falling on snowpack. Will monitor this situation for
potential hydrologic highlights. With the warm air aloft moving over
cooler air at the surface over the plains of north central Montana
Saturday night into Sunday morning, have included a slight chance of
freezing drizzle there. The westerly downslope winds will quickly
spread east across the area during the day on Sunday, warming
temperatures well into the 40s by afternoon. Temperatures will
remain similarly mild through Monday. As the disturbance exits the
area Monday night, the chance for precipitation will be limited to
the mountains into Tuesday. However, a weak cold front will move
south through the area on Tuesday, cooling temperatures to near
seasonal averages. As was mentioned yesterday, a cold and moist
weather system will move southeast from the Gulf of Alaska and into
the northern Rockies for Wednesday (Christmas Eve Day) into Thursday
(Christmas Day). There is still a good chance of precipitation with
this system across the area, but forecast models are trending a bit
farther south with the heaviest precipitation, focusing it more over
southwest Montana than central Montana. Have therefore made this
adjustment to the forecast. There is still a good indication that
temperatures will cool significantly below normal through this
period, for widespread light snow. Will continue to monitor the
progress of this system for potential winter weather highlights, as
this system will likely negatively impact holiday travel. Coulston

&&

.AVIATION...
UPDATED 1745Z.
VFR conditions are indicated at all terminals through the forecast
period. Mid-level SCT to at times BKN clouds will continue to move
across the region. Mountain top obscuration is likely at times along
the Continental Divide and over the southwest ranges. A
strengthening lee trough is raising southwest winds over the
north-central plains. Confidence is high that fog will not return
this period, but cannot rule out redevelopment at KHVR/KLWT. VCFG is
indicated at KHLN anticipating the potential for a few hours of
overnight valley fog in calm conditions.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  27  41  28  40 /  10  10  20   0
CTB  24  39  27  37 /  10  10   0  10
HLN  20  36  22  36 /  10  20  40  10
BZN  17  33  19  34 /   0  10  50  10
WEY  20  33  21  32 /  40  50  60  50
DLN  20  38  21  36 /   0  20  40  10
HVR  21  39  27  40 /  10  10  20   0
LWT  25  45  26  42 /   0   0  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 182143
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
243 PM MST Thu Dec 18 2014

.DISCUSSION...
Tonight through Saturday...The freezing fog advisory for northern
Blaine and northern Hill Counties has been cancelled as visibilities
have generally improved.A couple of weather disturbances aloft
will affect the forecast area during the period. The first one
will move through this evening. It looks like the only areas that
could see some light snow are the Little Belt Mountains..mountains
near the Idaho border..and mountains of the Rocky Mountain Front.
The next weather disturbance will move through Friday night. This
disturbance will have more moisture with it so mountains will
likely see a period of snow while there will be a chance of
precipitation for the lower elevations. This precipitation will
likely be a mix of types with rain and snow most prevalent but
there will also be a small threat of freezing rain over the
eastern plains. If freezing rain should occur do not think it will
last very long or be very widespread. Then Saturday westerly flow
aloft will develop and expect gusty southwest winds over the east
slopes of the Rocky Mountains. Blank

Saturday Night through Thursday...Through Monday, an upper level
high pressure ridge will strengthen over the eastern Pacific Ocean
and an upper level low pressure trough will deepen over central
Canada and the northern CONUS plains. The resulting strong
northwesterly flow aloft will bring increasing westerly surface
winds to the forecast area. Although forecast models are not quite
as strong with these winds as they have been the last couple of
nights, there is still a chance for High Wind criteria winds along
the Rocky Mountain Front and over some ridge tops. Will continue to
monitor this for potential High Wind highlights. This increasing
flow aloft will also bring warm and moist Pacific air and a weak
disturbance into the area. The main impact from this will be at
least a rain/snow mix in the mountains, if not mostly rain, while
the plains and valleys will have less of a chance of precipitation.
This could be a concern in the mountains with regard to rain
possibly falling on snowpack. Will monitor this situation for
potential hydrologic highlights. With the warm air aloft moving over
cooler air at the surface over the plains of north central Montana
Saturday night into Sunday morning, have included a slight chance of
freezing drizzle there. The westerly downslope winds will quickly
spread east across the area during the day on Sunday, warming
temperatures well into the 40s by afternoon. Temperatures will
remain similarly mild through Monday. As the disturbance exits the
area Monday night, the chance for precipitation will be limited to
the mountains into Tuesday. However, a weak cold front will move
south through the area on Tuesday, cooling temperatures to near
seasonal averages. As was mentioned yesterday, a cold and moist
weather system will move southeast from the Gulf of Alaska and into
the northern Rockies for Wednesday (Christmas Eve Day) into Thursday
(Christmas Day). There is still a good chance of precipitation with
this system across the area, but forecast models are trending a bit
farther south with the heaviest precipitation, focusing it more over
southwest Montana than central Montana. Have therefore made this
adjustment to the forecast. There is still a good indication that
temperatures will cool significantly below normal through this
period, for widespread light snow. Will continue to monitor the
progress of this system for potential winter weather highlights, as
this system will likely negatively impact holiday travel. Coulston

&&

.AVIATION...
UPDATED 1745Z.
VFR conditions are indicated at all terminals through the forecast
period. Mid-level SCT to at times BKN clouds will continue to move
across the region. Mountain top obscuration is likely at times along
the Continental Divide and over the southwest ranges. A
strengthening lee trough is raising southwest winds over the
north-central plains. Confidence is high that fog will not return
this period, but cannot rule out redevelopment at KHVR/KLWT. VCFG is
indicated at KHLN anticipating the potential for a few hours of
overnight valley fog in calm conditions.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  27  41  28  40 /  10  10  20   0
CTB  24  39  27  37 /  10  10   0  10
HLN  20  36  22  36 /  10  20  40  10
BZN  17  33  19  34 /   0  10  50  10
WEY  20  33  21  32 /  40  50  60  50
DLN  20  38  21  36 /   0  20  40  10
HVR  21  39  27  40 /  10  10  20   0
LWT  25  45  26  42 /   0   0  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 181751
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1045 AM MST Thu Dec 18 2014

Aviation Section Updated.

.UPDATE...
A check of satellite observations/web cameras/calls to spotters
indicates that dense freezing fog is confined to near and north of
the Milk River so have dropped that portion of the freezing fog
south of the Milk River. Otherwise a weather disturbance aloft
will be moving through the Continental Divide this afternoon so
followed the Missoula weather offices`s lead and increased the
chances of snow over the western mountains for this afternoon.
It still looks like this disturbance will only produce light
snow. Also increased high temperatures today except in the area of
the freezing fog advisory. Finally guidance suggests skies will be
partly cloudy at least in northwest portions of the plains by late
this afternoon so changed the forecast to reflect that. Blank

&&


.AVIATION...
UPDATED 1745Z.
VFR conditions are indicated at all terminals through the forecast
period. Mid-level SCT to at times BKN clouds will continue to move
across the region. Mountain top obscuration is likely at times along
the Continental Divide and over the southwest ranges. A
strengthening lee trough is raising southwest winds over the
north-central plains. Confidence is high that fog will not return
this period, but cannot rule out redevelopment at KHVR/KLWT. VCFG is
indicated at KHLN anticipating the potential for a few hours of
overnight valley fog in calm conditions.

&&

.PREV DISCUSSION...
/ISSUED 648 AM MST Thu Dec 18 2014/
FXUS65 KTFX 181348
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
648 AM MST Thu Dec 18 2014

UPDATE...

The freezing fog advisory has been extended until 11am and shifted
further east to include Blaine county and the Missouri Breaks. Fog
has eroded with westerly winds along the Rocky Mountain Front and
the Helena Valley, so the fog advisory was dropped in these areas.

&&

.PREV DISCUSSION...
/ISSUED 440 AM MST Thu Dec 18 2014/

Today through Saturday...Weak low pressure continues over Central
Montana and dynamics are also weak. To the west, an upper level
ridge will build over the Pacific Northwest. A low levels, a A low
pressure trof sits along the lee of the Rockies...just about over
Cut Bank. This surface trof should finally move east and west winds
will return to the northwest zones, and fog should only be a problem
farther east. The ridge will move over the Idaho Panhandle tonight
and moisture behind the ridge will move into the region late
Thursday night ahead of an approaching shortwave. This weak
shortwave will move quickly and not leave much time for weather to
development. Best chance for precipitation will be over the Rockies
and Southwest Montana.  A Pacific cold front associated with the
shortwave will cross the Rockies late Friday and Friday night. This
will bring some cooling across the zones Saturday although breezy
conditions and sun should keep max temps inline with previous days.
Zelzer

Saturday Night through Thursday...Through Monday, an upper level
high pressure ridge will strengthen over the eastern Pacific Ocean
and an upper level low pressure trough will deepen over central
Canada and the northern CONUS plains. The resulting strong
northwesterly flow aloft will bring increasing westerly surface
winds to the forecast area. Although forecast models are not quite
as strong with these winds as they have been the last couple of
nights, there is still a chance for High Wind criteria winds along
the Rocky Mountain Front and over some ridge tops. Will continue to
monitor this for potential High Wind highlights. This increasing
flow aloft will also bring warm and moist Pacific air and a weak
disturbance into the area. The main impact from this will be at
least a rain/snow mix in the mountains, if not mostly rain, while
the plains and valleys will have less of a chance of precipitation.
This could be a concern in the mountains with regard to rain
possibly falling on snowpack. Will monitor this situation for
potential hydrologic highlights. With the warm air aloft moving over
cooler air at the surface over the plains of north central Montana
Saturday night into Sunday morning, have included a slight chance of
freezing drizzle there. The westerly downslope winds will quickly
spread east across the area during the day on Sunday, warming
temperatures well into the 40s by afternoon. Temperatures will
remain similarly mild through Monday. As the disturbance exits the
area Monday night, the chance for precipitation will be limited to
the mountains into Tuesday. However, a weak cold front will move
south through the area on Tuesday, cooling temperatures to near
seasonal averages. As was mentioned yesterday, a cold and moist
weather system will move southeast from the Gulf of Alaska and into
the northern Rockies for Wednesday (Christmas Eve Day) into Thursday
(Christmas Day). There is still a good chance of precipitation with
this system across the area, but forecast models are trending a bit
farther south with the heaviest precipitation, focusing it more over
southwest Montana than central Montana. Have therefore made this
adjustment to the forecast. There is still a good indication that
temperatures will cool significantly below normal through this
period, for widespread light snow. Will continue to monitor the
progress of this system for potential winter weather highlights, as
this system will likely negatively impact holiday travel. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  43  27  41  28 /  10  10  10  20
CTB  42  24  39  28 /  10  10  10  10
HLN  39  20  36  22 /  10  10  20  30
BZN  36  17  33  19 /  10  20  20  40
WEY  34  20  33  23 /  30  40  40  50
DLN  35  20  38  22 /  10  10  20  30
HVR  35  21  39  26 /  10   0  10  20
LWT  43  24  44  27 /  10  10  10  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Blaine...Hill.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls









000
FXUS65 KTFX 181751
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1045 AM MST Thu Dec 18 2014

Aviation Section Updated.

.UPDATE...
A check of satellite observations/web cameras/calls to spotters
indicates that dense freezing fog is confined to near and north of
the Milk River so have dropped that portion of the freezing fog
south of the Milk River. Otherwise a weather disturbance aloft
will be moving through the Continental Divide this afternoon so
followed the Missoula weather offices`s lead and increased the
chances of snow over the western mountains for this afternoon.
It still looks like this disturbance will only produce light
snow. Also increased high temperatures today except in the area of
the freezing fog advisory. Finally guidance suggests skies will be
partly cloudy at least in northwest portions of the plains by late
this afternoon so changed the forecast to reflect that. Blank

&&


.AVIATION...
UPDATED 1745Z.
VFR conditions are indicated at all terminals through the forecast
period. Mid-level SCT to at times BKN clouds will continue to move
across the region. Mountain top obscuration is likely at times along
the Continental Divide and over the southwest ranges. A
strengthening lee trough is raising southwest winds over the
north-central plains. Confidence is high that fog will not return
this period, but cannot rule out redevelopment at KHVR/KLWT. VCFG is
indicated at KHLN anticipating the potential for a few hours of
overnight valley fog in calm conditions.

&&

.PREV DISCUSSION...
/ISSUED 648 AM MST Thu Dec 18 2014/
FXUS65 KTFX 181348
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
648 AM MST Thu Dec 18 2014

UPDATE...

The freezing fog advisory has been extended until 11am and shifted
further east to include Blaine county and the Missouri Breaks. Fog
has eroded with westerly winds along the Rocky Mountain Front and
the Helena Valley, so the fog advisory was dropped in these areas.

&&

.PREV DISCUSSION...
/ISSUED 440 AM MST Thu Dec 18 2014/

Today through Saturday...Weak low pressure continues over Central
Montana and dynamics are also weak. To the west, an upper level
ridge will build over the Pacific Northwest. A low levels, a A low
pressure trof sits along the lee of the Rockies...just about over
Cut Bank. This surface trof should finally move east and west winds
will return to the northwest zones, and fog should only be a problem
farther east. The ridge will move over the Idaho Panhandle tonight
and moisture behind the ridge will move into the region late
Thursday night ahead of an approaching shortwave. This weak
shortwave will move quickly and not leave much time for weather to
development. Best chance for precipitation will be over the Rockies
and Southwest Montana.  A Pacific cold front associated with the
shortwave will cross the Rockies late Friday and Friday night. This
will bring some cooling across the zones Saturday although breezy
conditions and sun should keep max temps inline with previous days.
Zelzer

Saturday Night through Thursday...Through Monday, an upper level
high pressure ridge will strengthen over the eastern Pacific Ocean
and an upper level low pressure trough will deepen over central
Canada and the northern CONUS plains. The resulting strong
northwesterly flow aloft will bring increasing westerly surface
winds to the forecast area. Although forecast models are not quite
as strong with these winds as they have been the last couple of
nights, there is still a chance for High Wind criteria winds along
the Rocky Mountain Front and over some ridge tops. Will continue to
monitor this for potential High Wind highlights. This increasing
flow aloft will also bring warm and moist Pacific air and a weak
disturbance into the area. The main impact from this will be at
least a rain/snow mix in the mountains, if not mostly rain, while
the plains and valleys will have less of a chance of precipitation.
This could be a concern in the mountains with regard to rain
possibly falling on snowpack. Will monitor this situation for
potential hydrologic highlights. With the warm air aloft moving over
cooler air at the surface over the plains of north central Montana
Saturday night into Sunday morning, have included a slight chance of
freezing drizzle there. The westerly downslope winds will quickly
spread east across the area during the day on Sunday, warming
temperatures well into the 40s by afternoon. Temperatures will
remain similarly mild through Monday. As the disturbance exits the
area Monday night, the chance for precipitation will be limited to
the mountains into Tuesday. However, a weak cold front will move
south through the area on Tuesday, cooling temperatures to near
seasonal averages. As was mentioned yesterday, a cold and moist
weather system will move southeast from the Gulf of Alaska and into
the northern Rockies for Wednesday (Christmas Eve Day) into Thursday
(Christmas Day). There is still a good chance of precipitation with
this system across the area, but forecast models are trending a bit
farther south with the heaviest precipitation, focusing it more over
southwest Montana than central Montana. Have therefore made this
adjustment to the forecast. There is still a good indication that
temperatures will cool significantly below normal through this
period, for widespread light snow. Will continue to monitor the
progress of this system for potential winter weather highlights, as
this system will likely negatively impact holiday travel. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  43  27  41  28 /  10  10  10  20
CTB  42  24  39  28 /  10  10  10  10
HLN  39  20  36  22 /  10  10  20  30
BZN  36  17  33  19 /  10  20  20  40
WEY  34  20  33  23 /  30  40  40  50
DLN  35  20  38  22 /  10  10  20  30
HVR  35  21  39  26 /  10   0  10  20
LWT  43  24  44  27 /  10  10  10  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Blaine...Hill.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls








000
FXUS65 KTFX 181713
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1013 AM MST Thu Dec 18 2014

.UPDATE...
A check of satellite observations/web cameras/calls to spotters
indicates that dense freezing fog is confined to near and north of
the Milk River so have dropped that portion of the freezing fog
south of the Milk River. Otherwise a weather disturbance aloft
will be moving through the Continental Divide this afternoon so
followed the Missoula weather offices`s lead and increased the
chances of snow over the western mountains for this afternoon.
It still looks like this disturbance will only produce light
snow. Also increased high temperatures today except in the area of
the freezing fog advisory. Finally guidance suggests skies will be
partly cloudy at least in northwest portions of the plains by late
this afternoon so changed the forecast to reflect that. Blank

&&


.AVIATION...
UPDATED 1140Z.
The airmass is again rather stagnant will ample low-level moisture.
An approaching shortwave should  increase winds and help dry lower
levels. Areas of dense fog are possible across northern portions of
Central Montana. Locally dense fog has also been noted in the Helena
Valley. Local IFR/MFR conditions will last until mid-morning. VFR
conditions are generally expected afterwards.

&&

.PREV DISCUSSION...
/ISSUED 648 AM MST Thu Dec 18 2014/
FXUS65 KTFX 181348
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
648 AM MST Thu Dec 18 2014

UPDATE...

The freezing fog advisory has been extended until 11am and shifted
further east to include Blaine county and the Missouri Breaks. Fog
has eroded with westerly winds along the Rocky Mountain Front and
the Helena Valley, so the fog advisory was dropped in these areas.

&&

.PREV DISCUSSION...
/ISSUED 440 AM MST Thu Dec 18 2014/

Today through Saturday...Weak low pressure continues over Central
Montana and dynamics are also weak. To the west, an upper level
ridge will build over the Pacific Northwest. A low levels, a A low
pressure trof sits along the lee of the Rockies...just about over
Cut Bank. This surface trof should finally move east and west winds
will return to the northwest zones, and fog should only be a problem
farther east. The ridge will move over the Idaho Panhandle tonight
and moisture behind the ridge will move into the region late
Thursday night ahead of an approaching shortwave. This weak
shortwave will move quickly and not leave much time for weather to
development. Best chance for precipitation will be over the Rockies
and Southwest Montana.  A Pacific cold front associated with the
shortwave will cross the Rockies late Friday and Friday night. This
will bring some cooling across the zones Saturday although breezy
conditions and sun should keep max temps inline with previous days.
Zelzer

Saturday Night through Thursday...Through Monday, an upper level
high pressure ridge will strengthen over the eastern Pacific Ocean
and an upper level low pressure trough will deepen over central
Canada and the northern CONUS plains. The resulting strong
northwesterly flow aloft will bring increasing westerly surface
winds to the forecast area. Although forecast models are not quite
as strong with these winds as they have been the last couple of
nights, there is still a chance for High Wind criteria winds along
the Rocky Mountain Front and over some ridge tops. Will continue to
monitor this for potential High Wind highlights. This increasing
flow aloft will also bring warm and moist Pacific air and a weak
disturbance into the area. The main impact from this will be at
least a rain/snow mix in the mountains, if not mostly rain, while
the plains and valleys will have less of a chance of precipitation.
This could be a concern in the mountains with regard to rain
possibly falling on snowpack. Will monitor this situation for
potential hydrologic highlights. With the warm air aloft moving over
cooler air at the surface over the plains of north central Montana
Saturday night into Sunday morning, have included a slight chance of
freezing drizzle there. The westerly downslope winds will quickly
spread east across the area during the day on Sunday, warming
temperatures well into the 40s by afternoon. Temperatures will
remain similarly mild through Monday. As the disturbance exits the
area Monday night, the chance for precipitation will be limited to
the mountains into Tuesday. However, a weak cold front will move
south through the area on Tuesday, cooling temperatures to near
seasonal averages. As was mentioned yesterday, a cold and moist
weather system will move southeast from the Gulf of Alaska and into
the northern Rockies for Wednesday (Christmas Eve Day) into Thursday
(Christmas Day). There is still a good chance of precipitation with
this system across the area, but forecast models are trending a bit
farther south with the heaviest precipitation, focusing it more over
southwest Montana than central Montana. Have therefore made this
adjustment to the forecast. There is still a good indication that
temperatures will cool significantly below normal through this
period, for widespread light snow. Will continue to monitor the
progress of this system for potential winter weather highlights, as
this system will likely negatively impact holiday travel. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  43  27  41  28 /  10  10  10  20
CTB  42  24  39  28 /  10  10  10  10
HLN  39  20  36  22 /  10  10  20  30
BZN  36  17  33  19 /  10  20  20  40
WEY  34  20  33  23 /  30  40  40  50
DLN  35  20  38  22 /  10  10  20  30
HVR  35  21  39  26 /  10   0  10  20
LWT  43  24  44  27 /  10  10  10  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Blaine...Hill.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 181713
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1013 AM MST Thu Dec 18 2014

.UPDATE...
A check of satellite observations/web cameras/calls to spotters
indicates that dense freezing fog is confined to near and north of
the Milk River so have dropped that portion of the freezing fog
south of the Milk River. Otherwise a weather disturbance aloft
will be moving through the Continental Divide this afternoon so
followed the Missoula weather offices`s lead and increased the
chances of snow over the western mountains for this afternoon.
It still looks like this disturbance will only produce light
snow. Also increased high temperatures today except in the area of
the freezing fog advisory. Finally guidance suggests skies will be
partly cloudy at least in northwest portions of the plains by late
this afternoon so changed the forecast to reflect that. Blank

&&


.AVIATION...
UPDATED 1140Z.
The airmass is again rather stagnant will ample low-level moisture.
An approaching shortwave should  increase winds and help dry lower
levels. Areas of dense fog are possible across northern portions of
Central Montana. Locally dense fog has also been noted in the Helena
Valley. Local IFR/MFR conditions will last until mid-morning. VFR
conditions are generally expected afterwards.

&&

.PREV DISCUSSION...
/ISSUED 648 AM MST Thu Dec 18 2014/
FXUS65 KTFX 181348
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
648 AM MST Thu Dec 18 2014

UPDATE...

The freezing fog advisory has been extended until 11am and shifted
further east to include Blaine county and the Missouri Breaks. Fog
has eroded with westerly winds along the Rocky Mountain Front and
the Helena Valley, so the fog advisory was dropped in these areas.

&&

.PREV DISCUSSION...
/ISSUED 440 AM MST Thu Dec 18 2014/

Today through Saturday...Weak low pressure continues over Central
Montana and dynamics are also weak. To the west, an upper level
ridge will build over the Pacific Northwest. A low levels, a A low
pressure trof sits along the lee of the Rockies...just about over
Cut Bank. This surface trof should finally move east and west winds
will return to the northwest zones, and fog should only be a problem
farther east. The ridge will move over the Idaho Panhandle tonight
and moisture behind the ridge will move into the region late
Thursday night ahead of an approaching shortwave. This weak
shortwave will move quickly and not leave much time for weather to
development. Best chance for precipitation will be over the Rockies
and Southwest Montana.  A Pacific cold front associated with the
shortwave will cross the Rockies late Friday and Friday night. This
will bring some cooling across the zones Saturday although breezy
conditions and sun should keep max temps inline with previous days.
Zelzer

Saturday Night through Thursday...Through Monday, an upper level
high pressure ridge will strengthen over the eastern Pacific Ocean
and an upper level low pressure trough will deepen over central
Canada and the northern CONUS plains. The resulting strong
northwesterly flow aloft will bring increasing westerly surface
winds to the forecast area. Although forecast models are not quite
as strong with these winds as they have been the last couple of
nights, there is still a chance for High Wind criteria winds along
the Rocky Mountain Front and over some ridge tops. Will continue to
monitor this for potential High Wind highlights. This increasing
flow aloft will also bring warm and moist Pacific air and a weak
disturbance into the area. The main impact from this will be at
least a rain/snow mix in the mountains, if not mostly rain, while
the plains and valleys will have less of a chance of precipitation.
This could be a concern in the mountains with regard to rain
possibly falling on snowpack. Will monitor this situation for
potential hydrologic highlights. With the warm air aloft moving over
cooler air at the surface over the plains of north central Montana
Saturday night into Sunday morning, have included a slight chance of
freezing drizzle there. The westerly downslope winds will quickly
spread east across the area during the day on Sunday, warming
temperatures well into the 40s by afternoon. Temperatures will
remain similarly mild through Monday. As the disturbance exits the
area Monday night, the chance for precipitation will be limited to
the mountains into Tuesday. However, a weak cold front will move
south through the area on Tuesday, cooling temperatures to near
seasonal averages. As was mentioned yesterday, a cold and moist
weather system will move southeast from the Gulf of Alaska and into
the northern Rockies for Wednesday (Christmas Eve Day) into Thursday
(Christmas Day). There is still a good chance of precipitation with
this system across the area, but forecast models are trending a bit
farther south with the heaviest precipitation, focusing it more over
southwest Montana than central Montana. Have therefore made this
adjustment to the forecast. There is still a good indication that
temperatures will cool significantly below normal through this
period, for widespread light snow. Will continue to monitor the
progress of this system for potential winter weather highlights, as
this system will likely negatively impact holiday travel. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  43  27  41  28 /  10  10  10  20
CTB  42  24  39  28 /  10  10  10  10
HLN  39  20  36  22 /  10  10  20  30
BZN  36  17  33  19 /  10  20  20  40
WEY  34  20  33  23 /  30  40  40  50
DLN  35  20  38  22 /  10  10  20  30
HVR  35  21  39  26 /  10   0  10  20
LWT  43  24  44  27 /  10  10  10  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Blaine...Hill.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 181348
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
648 AM MST Thu Dec 18 2014

.UPDATE...

The freezing fog advisory has been extended until 11am and shifted
further east to include Blaine county and the Missouri Breaks. Fog
has eroded with westerly winds along the Rocky Mountain Front and
the Helena Valley, so the fog advisory was dropped in these areas.

&&

.AVIATION...
UPDATED 1140Z.
The airmass is again rather stagnant will ample low-level moisture.
An approaching shortwave should  increase winds and help dry lower
levels. Areas of dense fog are possible across northern portions of
Central Montana. Locally dense fog has also been noted in the Helena
Valley. Local IFR/MFR conditions will last until mid-morning. VFR
conditions are generally expected afterwards.

&&

.PREV DISCUSSION...
/ISSUED 440 AM MST Thu Dec 18 2014/

Today through Saturday...Weak low pressure continues over Central
Montana and dynamics are also weak. To the west, an upper level
ridge will build over the Pacific Northwest. A low levels, a A low
pressure trof sits along the lee of the Rockies...just about over
Cut Bank. This surface trof should finally move east and west winds
will return to the northwest zones, and fog should only be a problem
farther east. The ridge will move over the Idaho Panhandle tonight
and moisture behind the ridge will move into the region late
Thursday night ahead of an approaching shortwave. This weak
shortwave will move quickly and not leave much time for weather to
development. Best chance for precipitation will be over the Rockies
and Southwest Montana.  A Pacific cold front associated with the
shortwave will cross the Rockies late Friday and Friday night. This
will bring some cooling across the zones Saturday although breezy
conditions and sun should keep max temps inline with previous days.
Zelzer

Saturday Night through Thursday...Through Monday, an upper level
high pressure ridge will strengthen over the eastern Pacific Ocean
and an upper level low pressure trough will deepen over central
Canada and the northern CONUS plains. The resulting strong
northwesterly flow aloft will bring increasing westerly surface
winds to the forecast area. Although forecast models are not quite
as strong with these winds as they have been the last couple of
nights, there is still a chance for High Wind criteria winds along
the Rocky Mountain Front and over some ridge tops. Will continue to
monitor this for potential High Wind highlights. This increasing
flow aloft will also bring warm and moist Pacific air and a weak
disturbance into the area. The main impact from this will be at
least a rain/snow mix in the mountains, if not mostly rain, while
the plains and valleys will have less of a chance of precipitation.
This could be a concern in the mountains with regard to rain
possibly falling on snowpack. Will monitor this situation for
potential hydrologic highlights. With the warm air aloft moving over
cooler air at the surface over the plains of north central Montana
Saturday night into Sunday morning, have included a slight chance of
freezing drizzle there. The westerly downslope winds will quickly
spread east across the area during the day on Sunday, warming
temperatures well into the 40s by afternoon. Temperatures will
remain similarly mild through Monday. As the disturbance exits the
area Monday night, the chance for precipitation will be limited to
the mountains into Tuesday. However, a weak cold front will move
south through the area on Tuesday, cooling temperatures to near
seasonal averages. As was mentioned yesterday, a cold and moist
weather system will move southeast from the Gulf of Alaska and into
the northern Rockies for Wednesday (Christmas Eve Day) into Thursday
(Christmas Day). There is still a good chance of precipitation with
this system across the area, but forecast models are trending a bit
farther south with the heaviest precipitation, focusing it more over
southwest Montana than central Montana. Have therefore made this
adjustment to the forecast. There is still a good indication that
temperatures will cool significantly below normal through this
period, for widespread light snow. Will continue to monitor the
progress of this system for potential winter weather highlights, as
this system will likely negatively impact holiday travel. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  41  27  41  28 /  10  10  10  20
CTB  38  24  39  28 /  10  10  10  10
HLN  35  20  36  22 /  10  10  20  30
BZN  32  17  33  19 /  10  20  20  40
WEY  32  20  33  23 /  30  40  40  50
DLN  35  20  38  22 /  10  10  20  30
HVR  37  21  39  26 /  10   0  10  20
LWT  43  24  44  27 /  10  10  10  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Blaine...
Chouteau...Fergus...Hill...Liberty.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 181348
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
648 AM MST Thu Dec 18 2014

.UPDATE...

The freezing fog advisory has been extended until 11am and shifted
further east to include Blaine county and the Missouri Breaks. Fog
has eroded with westerly winds along the Rocky Mountain Front and
the Helena Valley, so the fog advisory was dropped in these areas.

&&

.AVIATION...
UPDATED 1140Z.
The airmass is again rather stagnant will ample low-level moisture.
An approaching shortwave should  increase winds and help dry lower
levels. Areas of dense fog are possible across northern portions of
Central Montana. Locally dense fog has also been noted in the Helena
Valley. Local IFR/MFR conditions will last until mid-morning. VFR
conditions are generally expected afterwards.

&&

.PREV DISCUSSION...
/ISSUED 440 AM MST Thu Dec 18 2014/

Today through Saturday...Weak low pressure continues over Central
Montana and dynamics are also weak. To the west, an upper level
ridge will build over the Pacific Northwest. A low levels, a A low
pressure trof sits along the lee of the Rockies...just about over
Cut Bank. This surface trof should finally move east and west winds
will return to the northwest zones, and fog should only be a problem
farther east. The ridge will move over the Idaho Panhandle tonight
and moisture behind the ridge will move into the region late
Thursday night ahead of an approaching shortwave. This weak
shortwave will move quickly and not leave much time for weather to
development. Best chance for precipitation will be over the Rockies
and Southwest Montana.  A Pacific cold front associated with the
shortwave will cross the Rockies late Friday and Friday night. This
will bring some cooling across the zones Saturday although breezy
conditions and sun should keep max temps inline with previous days.
Zelzer

Saturday Night through Thursday...Through Monday, an upper level
high pressure ridge will strengthen over the eastern Pacific Ocean
and an upper level low pressure trough will deepen over central
Canada and the northern CONUS plains. The resulting strong
northwesterly flow aloft will bring increasing westerly surface
winds to the forecast area. Although forecast models are not quite
as strong with these winds as they have been the last couple of
nights, there is still a chance for High Wind criteria winds along
the Rocky Mountain Front and over some ridge tops. Will continue to
monitor this for potential High Wind highlights. This increasing
flow aloft will also bring warm and moist Pacific air and a weak
disturbance into the area. The main impact from this will be at
least a rain/snow mix in the mountains, if not mostly rain, while
the plains and valleys will have less of a chance of precipitation.
This could be a concern in the mountains with regard to rain
possibly falling on snowpack. Will monitor this situation for
potential hydrologic highlights. With the warm air aloft moving over
cooler air at the surface over the plains of north central Montana
Saturday night into Sunday morning, have included a slight chance of
freezing drizzle there. The westerly downslope winds will quickly
spread east across the area during the day on Sunday, warming
temperatures well into the 40s by afternoon. Temperatures will
remain similarly mild through Monday. As the disturbance exits the
area Monday night, the chance for precipitation will be limited to
the mountains into Tuesday. However, a weak cold front will move
south through the area on Tuesday, cooling temperatures to near
seasonal averages. As was mentioned yesterday, a cold and moist
weather system will move southeast from the Gulf of Alaska and into
the northern Rockies for Wednesday (Christmas Eve Day) into Thursday
(Christmas Day). There is still a good chance of precipitation with
this system across the area, but forecast models are trending a bit
farther south with the heaviest precipitation, focusing it more over
southwest Montana than central Montana. Have therefore made this
adjustment to the forecast. There is still a good indication that
temperatures will cool significantly below normal through this
period, for widespread light snow. Will continue to monitor the
progress of this system for potential winter weather highlights, as
this system will likely negatively impact holiday travel. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  41  27  41  28 /  10  10  10  20
CTB  38  24  39  28 /  10  10  10  10
HLN  35  20  36  22 /  10  10  20  30
BZN  32  17  33  19 /  10  20  20  40
WEY  32  20  33  23 /  30  40  40  50
DLN  35  20  38  22 /  10  10  20  30
HVR  37  21  39  26 /  10   0  10  20
LWT  43  24  44  27 /  10  10  10  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Blaine...
Chouteau...Fergus...Hill...Liberty.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 181348
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
648 AM MST Thu Dec 18 2014

.UPDATE...

The freezing fog advisory has been extended until 11am and shifted
further east to include Blaine county and the Missouri Breaks. Fog
has eroded with westerly winds along the Rocky Mountain Front and
the Helena Valley, so the fog advisory was dropped in these areas.

&&

.AVIATION...
UPDATED 1140Z.
The airmass is again rather stagnant will ample low-level moisture.
An approaching shortwave should  increase winds and help dry lower
levels. Areas of dense fog are possible across northern portions of
Central Montana. Locally dense fog has also been noted in the Helena
Valley. Local IFR/MFR conditions will last until mid-morning. VFR
conditions are generally expected afterwards.

&&

.PREV DISCUSSION...
/ISSUED 440 AM MST Thu Dec 18 2014/

Today through Saturday...Weak low pressure continues over Central
Montana and dynamics are also weak. To the west, an upper level
ridge will build over the Pacific Northwest. A low levels, a A low
pressure trof sits along the lee of the Rockies...just about over
Cut Bank. This surface trof should finally move east and west winds
will return to the northwest zones, and fog should only be a problem
farther east. The ridge will move over the Idaho Panhandle tonight
and moisture behind the ridge will move into the region late
Thursday night ahead of an approaching shortwave. This weak
shortwave will move quickly and not leave much time for weather to
development. Best chance for precipitation will be over the Rockies
and Southwest Montana.  A Pacific cold front associated with the
shortwave will cross the Rockies late Friday and Friday night. This
will bring some cooling across the zones Saturday although breezy
conditions and sun should keep max temps inline with previous days.
Zelzer

Saturday Night through Thursday...Through Monday, an upper level
high pressure ridge will strengthen over the eastern Pacific Ocean
and an upper level low pressure trough will deepen over central
Canada and the northern CONUS plains. The resulting strong
northwesterly flow aloft will bring increasing westerly surface
winds to the forecast area. Although forecast models are not quite
as strong with these winds as they have been the last couple of
nights, there is still a chance for High Wind criteria winds along
the Rocky Mountain Front and over some ridge tops. Will continue to
monitor this for potential High Wind highlights. This increasing
flow aloft will also bring warm and moist Pacific air and a weak
disturbance into the area. The main impact from this will be at
least a rain/snow mix in the mountains, if not mostly rain, while
the plains and valleys will have less of a chance of precipitation.
This could be a concern in the mountains with regard to rain
possibly falling on snowpack. Will monitor this situation for
potential hydrologic highlights. With the warm air aloft moving over
cooler air at the surface over the plains of north central Montana
Saturday night into Sunday morning, have included a slight chance of
freezing drizzle there. The westerly downslope winds will quickly
spread east across the area during the day on Sunday, warming
temperatures well into the 40s by afternoon. Temperatures will
remain similarly mild through Monday. As the disturbance exits the
area Monday night, the chance for precipitation will be limited to
the mountains into Tuesday. However, a weak cold front will move
south through the area on Tuesday, cooling temperatures to near
seasonal averages. As was mentioned yesterday, a cold and moist
weather system will move southeast from the Gulf of Alaska and into
the northern Rockies for Wednesday (Christmas Eve Day) into Thursday
(Christmas Day). There is still a good chance of precipitation with
this system across the area, but forecast models are trending a bit
farther south with the heaviest precipitation, focusing it more over
southwest Montana than central Montana. Have therefore made this
adjustment to the forecast. There is still a good indication that
temperatures will cool significantly below normal through this
period, for widespread light snow. Will continue to monitor the
progress of this system for potential winter weather highlights, as
this system will likely negatively impact holiday travel. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  41  27  41  28 /  10  10  10  20
CTB  38  24  39  28 /  10  10  10  10
HLN  35  20  36  22 /  10  10  20  30
BZN  32  17  33  19 /  10  20  20  40
WEY  32  20  33  23 /  30  40  40  50
DLN  35  20  38  22 /  10  10  20  30
HVR  37  21  39  26 /  10   0  10  20
LWT  43  24  44  27 /  10  10  10  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Blaine...
Chouteau...Fergus...Hill...Liberty.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 181141
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
440 AM MST Thu Dec 18 2014

.DISCUSSION...

Today through Saturday...Weak low pressure continues over Central
Montana and dynamics are also weak. To the west, an upper level
ridge will build over the Pacific Northwest. A low levels, a A low
pressure trof sits along the lee of the Rockies...just about over
Cut Bank. This surface trof should finally move east and west winds
will return to the northwest zones, and fog should only be a problem
farther east. The ridge will move over the Idaho Panhandle tonight
and moisture behind the ridge will move into the region late
Thursday night ahead of an approaching shortwave. This weak
shortwave will move quickly and not leave much time for weather to
development. Best chance for precipitation will be over the Rockies
and Southwest Montana.  A Pacific cold front associated with the
shortwave will cross the Rockies late Friday and Friday night. This
will bring some cooling across the zones Saturday although breezy
conditions and sun should keep max temps inline with previous days.
Zelzer

Saturday Night through Thursday...Through Monday, an upper level
high pressure ridge will strengthen over the eastern Pacific Ocean
and an upper level low pressure trough will deepen over central
Canada and the northern CONUS plains. The resulting strong
northwesterly flow aloft will bring increasing westerly surface
winds to the forecast area. Although forecast models are not quite
as strong with these winds as they have been the last couple of
nights, there is still a chance for High Wind criteria winds along
the Rocky Mountain Front and over some ridge tops. Will continue to
monitor this for potential High Wind highlights. This increasing
flow aloft will also bring warm and moist Pacific air and a weak
disturbance into the area. The main impact from this will be at
least a rain/snow mix in the mountains, if not mostly rain, while
the plains and valleys will have less of a chance of precipitation.
This could be a concern in the mountains with regard to rain
possibly falling on snowpack. Will monitor this situation for
potential hydrologic highlights. With the warm air aloft moving over
cooler air at the surface over the plains of north central Montana
Saturday night into Sunday morning, have included a slight chance of
freezing drizzle there. The westerly downslope winds will quickly
spread east across the area during the day on Sunday, warming
temperatures well into the 40s by afternoon. Temperatures will
remain similarly mild through Monday. As the disturbance exits the
area Monday night, the chance for precipitation will be limited to
the mountains into Tuesday. However, a weak cold front will move
south through the area on Tuesday, cooling temperatures to near
seasonal averages. As was mentioned yesterday, a cold and moist
weather system will move southeast from the Gulf of Alaska and into
the northern Rockies for Wednesday (Christmas Eve Day) into Thursday
(Christmas Day). There is still a good chance of precipitation with
this system across the area, but forecast models are trending a bit
farther south with the heaviest precipitation, focusing it more over
southwest Montana than central Montana. Have therefore made this
adjustment to the forecast. There is still a good indication that
temperatures will cool significantly below normal through this
period, for widespread light snow. Will continue to monitor the
progress of this system for potential winter weather highlights, as
this system will likely negatively impact holiday travel. Coulston

&&

.AVIATION...
UPDATED 1140Z.
The airmass is again rather stagnant will ample low-level moisture.
An approaching shortwave should  increase winds and help dry lower
levels. Areas of dense fog are possible across northern portions of
Central Montana. Locally dense fog has also been noted in the Helena
Valley. Local IFR/MFR conditions will last until mid-morning. VFR
conditions are generally expected afterwards.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  41  27  41  28 /  10  10  10  20
CTB  38  24  39  28 /  10  10  10  10
HLN  35  20  36  22 /  10  10  20  30
BZN  32  17  33  19 /  10  20  20  40
WEY  32  20  33  23 /  30  40  40  50
DLN  35  20  38  22 /  10  10  20  30
HVR  37  21  39  26 /  10   0  10  20
LWT  43  24  44  27 /  10  10  10  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 9 AM MST this morning Central and
Southern Lewis and Clark...Eastern Glacier...Eastern Pondera...
Eastern Teton...Hill...Liberty...Southern Rocky Mountain Front...
Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls









000
FXUS65 KTFX 181141
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
440 AM MST Thu Dec 18 2014

.DISCUSSION...

Today through Saturday...Weak low pressure continues over Central
Montana and dynamics are also weak. To the west, an upper level
ridge will build over the Pacific Northwest. A low levels, a A low
pressure trof sits along the lee of the Rockies...just about over
Cut Bank. This surface trof should finally move east and west winds
will return to the northwest zones, and fog should only be a problem
farther east. The ridge will move over the Idaho Panhandle tonight
and moisture behind the ridge will move into the region late
Thursday night ahead of an approaching shortwave. This weak
shortwave will move quickly and not leave much time for weather to
development. Best chance for precipitation will be over the Rockies
and Southwest Montana.  A Pacific cold front associated with the
shortwave will cross the Rockies late Friday and Friday night. This
will bring some cooling across the zones Saturday although breezy
conditions and sun should keep max temps inline with previous days.
Zelzer

Saturday Night through Thursday...Through Monday, an upper level
high pressure ridge will strengthen over the eastern Pacific Ocean
and an upper level low pressure trough will deepen over central
Canada and the northern CONUS plains. The resulting strong
northwesterly flow aloft will bring increasing westerly surface
winds to the forecast area. Although forecast models are not quite
as strong with these winds as they have been the last couple of
nights, there is still a chance for High Wind criteria winds along
the Rocky Mountain Front and over some ridge tops. Will continue to
monitor this for potential High Wind highlights. This increasing
flow aloft will also bring warm and moist Pacific air and a weak
disturbance into the area. The main impact from this will be at
least a rain/snow mix in the mountains, if not mostly rain, while
the plains and valleys will have less of a chance of precipitation.
This could be a concern in the mountains with regard to rain
possibly falling on snowpack. Will monitor this situation for
potential hydrologic highlights. With the warm air aloft moving over
cooler air at the surface over the plains of north central Montana
Saturday night into Sunday morning, have included a slight chance of
freezing drizzle there. The westerly downslope winds will quickly
spread east across the area during the day on Sunday, warming
temperatures well into the 40s by afternoon. Temperatures will
remain similarly mild through Monday. As the disturbance exits the
area Monday night, the chance for precipitation will be limited to
the mountains into Tuesday. However, a weak cold front will move
south through the area on Tuesday, cooling temperatures to near
seasonal averages. As was mentioned yesterday, a cold and moist
weather system will move southeast from the Gulf of Alaska and into
the northern Rockies for Wednesday (Christmas Eve Day) into Thursday
(Christmas Day). There is still a good chance of precipitation with
this system across the area, but forecast models are trending a bit
farther south with the heaviest precipitation, focusing it more over
southwest Montana than central Montana. Have therefore made this
adjustment to the forecast. There is still a good indication that
temperatures will cool significantly below normal through this
period, for widespread light snow. Will continue to monitor the
progress of this system for potential winter weather highlights, as
this system will likely negatively impact holiday travel. Coulston

&&

.AVIATION...
UPDATED 1140Z.
The airmass is again rather stagnant will ample low-level moisture.
An approaching shortwave should  increase winds and help dry lower
levels. Areas of dense fog are possible across northern portions of
Central Montana. Locally dense fog has also been noted in the Helena
Valley. Local IFR/MFR conditions will last until mid-morning. VFR
conditions are generally expected afterwards.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  41  27  41  28 /  10  10  10  20
CTB  38  24  39  28 /  10  10  10  10
HLN  35  20  36  22 /  10  10  20  30
BZN  32  17  33  19 /  10  20  20  40
WEY  32  20  33  23 /  30  40  40  50
DLN  35  20  38  22 /  10  10  20  30
HVR  37  21  39  26 /  10   0  10  20
LWT  43  24  44  27 /  10  10  10  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 9 AM MST this morning Central and
Southern Lewis and Clark...Eastern Glacier...Eastern Pondera...
Eastern Teton...Hill...Liberty...Southern Rocky Mountain Front...
Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls








000
FXUS65 KTFX 181029
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
329 AM MST Thu Dec 18 2014

.DISCUSSION...

Today through Saturday...Weak low pressure continues over Central
Montana and dynamics are also weak. To the west, an upper level
ridge will build over the Pacific Northwest. A low levels, a A low
pressure trof sits along the lee of the Rockies...just about over
Cut Bank. This surface trof should finally move east and west winds
will return to the northwest zones, and fog should only be a problem
farther east. The ridge will move over the Idaho Panhandle tonight
and moisture behind the ridge will move into the region late
Thursday night ahead of an approaching shortwave. This weak
shortwave will move quickly and not leave much time for weather to
development. Best chance for precipitation will be over the Rockies
and Southwest Montana.  A Pacific cold front associated with the
shortwave will cross the Rockies late Friday and Friday night. This
will bring some cooling across the zones Saturday although breezy
conditions and sun should keep max temps inline with previous days.
Zelzer

Saturday Night through Thursday...Through Monday, an upper level
high pressure ridge will strengthen over the eastern Pacific Ocean
and an upper level low pressure trough will deepen over central
Canada and the northern CONUS plains. The resulting strong
northwesterly flow aloft will bring increasing westerly surface
winds to the forecast area. Although forecast models are not quite
as strong with these winds as they have been the last couple of
nights, there is still a chance for High Wind criteria winds along
the Rocky Mountain Front and over some ridge tops. Will continue to
monitor this for potential High Wind highlights. This increasing
flow aloft will also bring warm and moist Pacific air and a weak
disturbance into the area. The main impact from this will be at
least a rain/snow mix in the mountains, if not mostly rain, while
the plains and valleys will have less of a chance of precipitation.
This could be a concern in the mountains with regard to rain
possibly falling on snowpack. Will monitor this situation for
potential hydrologic highlights. With the warm air aloft moving over
cooler air at the surface over the plains of north central Montana
Saturday night into Sunday morning, have included a slight chance of
freezing drizzle there. The westerly downslope winds will quickly
spread east across the area during the day on Sunday, warming
temperatures well into the 40s by afternoon. Temperatures will
remain similarly mild through Monday. As the disturbance exits the
area Monday night, the chance for precipitation will be limited to
the mountains into Tuesday. However, a weak cold front will move
south through the area on Tuesday, cooling temperatures to near
seasonal averages. As was mentioned yesterday, a cold and moist
weather system will move southeast from the Gulf of Alaska and into
the northern Rockies for Wednesday (Christmas Eve Day) into Thursday
(Christmas Day). There is still a good chance of precipitation with
this system across the area, but forecast models are trending a bit
farther south with the heaviest precipitation, focusing it more over
southwest Montana than central Montana. Have therefore made this
adjustment to the forecast. There is still a good indication that
temperatures will cool significantly below normal through this
period, for widespread light snow. Will continue to monitor the
progress of this system for potential winter weather highlights, as
this system will likely negatively impact holiday travel. Coulston

&&

.AVIATION...
UPDATED 0535Z.
Persistent freezing fog has started to erode at KCTB with downslope
mixing, transitioning to VFR conditions. Dense freezing fog has
developed further east along the highline including KHVR. Expect
this to continue with LIFR conditions through early morning. Patchy
fog is periodically moving across the airfield at KHLN, yielding
flight category changes on the order of tens of minutes. Otherwise,
VFR conditions prevail through the period under generally clear
skies. High cloud cover will increase Thursday as another weak
disturbance moves into western Montana. Nutter

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  41  27  41  28 /  10  10  10  20
CTB  38  24  39  28 /  10  10  10  10
HLN  35  20  36  22 /  10  10  20  30
BZN  32  17  33  19 /  10  20  20  40
WEY  32  20  33  23 /  30  40  40  50
DLN  35  20  38  22 /  10  10  20  30
HVR  37  21  39  26 /  10   0  10  20
LWT  43  24  44  27 /  10  10  10  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 9 AM MST this morning Central and
Southern Lewis and Clark...Eastern Glacier...Eastern Pondera...
Eastern Teton...Hill...Liberty...Southern Rocky Mountain Front...
Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 181029
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
329 AM MST Thu Dec 18 2014

.DISCUSSION...

Today through Saturday...Weak low pressure continues over Central
Montana and dynamics are also weak. To the west, an upper level
ridge will build over the Pacific Northwest. A low levels, a A low
pressure trof sits along the lee of the Rockies...just about over
Cut Bank. This surface trof should finally move east and west winds
will return to the northwest zones, and fog should only be a problem
farther east. The ridge will move over the Idaho Panhandle tonight
and moisture behind the ridge will move into the region late
Thursday night ahead of an approaching shortwave. This weak
shortwave will move quickly and not leave much time for weather to
development. Best chance for precipitation will be over the Rockies
and Southwest Montana.  A Pacific cold front associated with the
shortwave will cross the Rockies late Friday and Friday night. This
will bring some cooling across the zones Saturday although breezy
conditions and sun should keep max temps inline with previous days.
Zelzer

Saturday Night through Thursday...Through Monday, an upper level
high pressure ridge will strengthen over the eastern Pacific Ocean
and an upper level low pressure trough will deepen over central
Canada and the northern CONUS plains. The resulting strong
northwesterly flow aloft will bring increasing westerly surface
winds to the forecast area. Although forecast models are not quite
as strong with these winds as they have been the last couple of
nights, there is still a chance for High Wind criteria winds along
the Rocky Mountain Front and over some ridge tops. Will continue to
monitor this for potential High Wind highlights. This increasing
flow aloft will also bring warm and moist Pacific air and a weak
disturbance into the area. The main impact from this will be at
least a rain/snow mix in the mountains, if not mostly rain, while
the plains and valleys will have less of a chance of precipitation.
This could be a concern in the mountains with regard to rain
possibly falling on snowpack. Will monitor this situation for
potential hydrologic highlights. With the warm air aloft moving over
cooler air at the surface over the plains of north central Montana
Saturday night into Sunday morning, have included a slight chance of
freezing drizzle there. The westerly downslope winds will quickly
spread east across the area during the day on Sunday, warming
temperatures well into the 40s by afternoon. Temperatures will
remain similarly mild through Monday. As the disturbance exits the
area Monday night, the chance for precipitation will be limited to
the mountains into Tuesday. However, a weak cold front will move
south through the area on Tuesday, cooling temperatures to near
seasonal averages. As was mentioned yesterday, a cold and moist
weather system will move southeast from the Gulf of Alaska and into
the northern Rockies for Wednesday (Christmas Eve Day) into Thursday
(Christmas Day). There is still a good chance of precipitation with
this system across the area, but forecast models are trending a bit
farther south with the heaviest precipitation, focusing it more over
southwest Montana than central Montana. Have therefore made this
adjustment to the forecast. There is still a good indication that
temperatures will cool significantly below normal through this
period, for widespread light snow. Will continue to monitor the
progress of this system for potential winter weather highlights, as
this system will likely negatively impact holiday travel. Coulston

&&

.AVIATION...
UPDATED 0535Z.
Persistent freezing fog has started to erode at KCTB with downslope
mixing, transitioning to VFR conditions. Dense freezing fog has
developed further east along the highline including KHVR. Expect
this to continue with LIFR conditions through early morning. Patchy
fog is periodically moving across the airfield at KHLN, yielding
flight category changes on the order of tens of minutes. Otherwise,
VFR conditions prevail through the period under generally clear
skies. High cloud cover will increase Thursday as another weak
disturbance moves into western Montana. Nutter

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  41  27  41  28 /  10  10  10  20
CTB  38  24  39  28 /  10  10  10  10
HLN  35  20  36  22 /  10  10  20  30
BZN  32  17  33  19 /  10  20  20  40
WEY  32  20  33  23 /  30  40  40  50
DLN  35  20  38  22 /  10  10  20  30
HVR  37  21  39  26 /  10   0  10  20
LWT  43  24  44  27 /  10  10  10  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 9 AM MST this morning Central and
Southern Lewis and Clark...Eastern Glacier...Eastern Pondera...
Eastern Teton...Hill...Liberty...Southern Rocky Mountain Front...
Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 180542
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1035 PM MST Wed Dec 17 2014

Aviation Section Updated.

.UPDATE...
Latest observations show freezing fog, dense in areas, continuing
over most of the Hiline counties and redeveloping in parts of
Pondera and Teton counties. So have extended the freezing fog
advisory for eastern Glacier and Toole and added eastern Pondera,
Teton, Liberty, and Hill counties to the advisory that now goes
until 9am Thurs. Also adjusted the overnight lows in the fog areas
as several sites were at/below the forecast minimum temps. A weak
shortwave trof currently crossing western MT may help increase the
surface winds east of the Divide during the overnight hours to
help dissipate some of the fog, but confidence is only marginal
for that to occur.
Waranauskas

&&

.AVIATION...
UPDATED 0535Z.
Persistent freezing fog has started to erode at KCTB with downslope
mixing, transitioning to VFR conditions. Dense freezing fog has
developed further east along the highline including KHVR. Expect
this to continue with LIFR conditions through early morning. Patchy
fog is periodically moving across the airfield at KHLN, yielding
flight category changes on the order of tens of minutes. Otherwise,
VFR conditions prevail through the period under generally clear
skies. High cloud cover will increase Thursday as another weak
disturbance moves into western Montana. Nutter

&&

.PREV DISCUSSION...
/ISSUED 435 PM MST Wed Dec 17 2014/
Wednesday night through Friday...A rather quiet and cool end to
the work week is expected as no major systems are expected to move
over the area in this time frame. Temperatures will remain near
seasonal values as weak shortwave toughing on Thursday will be
followed by a week shortwave ridge on Friday. The biggest impact
during this time period will be the persistent freezing fog over
parts of Central and North Central Montana. Have extended the
advisory currently in effect until 9 pm for areas around Cut Bank
and Shelby. Westerly winds should develop around 6 pm and
eventual scour out the fog. However, there is a chance that the
nocturnal boundary layer will strengthen the inversion and will
limit any potential for the west winds to move the fog out of the
area until Thursday when a weak shortwave moves through the area.
Widespread moisture is not expected at this time with this
disturbance...however some isolated mountain snow showers are
possible. Suk

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate
that the pattern will then change for Saturday night through
Tuesday. An upper level high pressure ridge will strengthen off
the California coast and a low pressure trough will deepen from
Hudson Bay into the Great Lakes. This will result in Montana being
under a strong northwesterly flow aloft. The models indicate that
the strongest winds aloft will occur Sunday into Sunday night with
the passage of a disturbance embedded in the flow. However, the
models differ on just how strong these winds will be. The ECMWF
only forecasts winds of 45 to 55 kts at 700 mb, while the GFS
generally has 60 to 70 kt winds. Have therefore used a compromise
solution between these two models with regards to surface wind
strength. Despite this difference, this set-up will bring gusty
westerly downslope winds to much of the area, but especially over
the plains of north central Montana. In fact, some areas along the
Rocky Mountain Front could approach High Wind criteria (40 mph
sustained/58 mph gusts). Confidence remains moderate that High
Wind highlights may be needed for this event. The only concern is
that the northwesterly wind direction is not as favorable for
widespread High Winds. There is also significant moisture with
this disturbance, so have continued to spread the chance for
precipitation out onto the plains. Winds aloft will decrease
somewhat after the passage of the disturbance, but the
northwesterly flow aloft will remain fairly moist, so have kept
the chance for precipitation above climatological normals across
the area into Tuesday. A potentially significant weather system
originating in the Gulf of Alaska is then forecast to move into
Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees
above normal. The warmest day of the period appears to be Monday,
when most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly
below seasonal averages by Wednesday. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  25  40  26  40 /  10  10  10  10
CTB  12  39  24  39 /  10  10  10  10
HLN  19  34  19  35 /  10  20  10  20
BZN  14  30  15  32 /  10  10  10  20
WEY  17  32  19  33 /  20  20  30  40
DLN  18  34  19  37 /  10  20  10  20
HVR  16  37  22  39 /  10  10  10  10
LWT  23  43  24  43 /  10  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 9 AM MST Thursday Eastern Glacier...
Eastern Pondera...Eastern Teton...Hill...Liberty...Southern
Rocky Mountain Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls








000
FXUS65 KTFX 180443
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
943 PM MST Wed Dec 17 2014

.UPDATE...
Latest observations show freezing fog, dense in areas, continuing
over most of the Hiline counties and redeveloping in parts of
Pondera and Teton counties. So have extended the freezing fog
advisory for eastern Glacier and Toole and added eastern Pondera,
Teton, Liberty, and Hill counties to the advisory that now goes
until 9am Thurs. Also adjusted the overnight lows in the fog areas
as several sites were at/below the forecast minimum temps. A weak
shortwave trof currently crossing western MT may help increase the
surface winds east of the Divide during the overnight hours to
help dissipate some of the fog, but confidence is only marginal
for that to occur.
Waranauskas

&&

.AVIATION...
UPDATED 2335Z.
Persistent freezing fog continues at KCTB with LIFR conditions.
Southwesterly downslope flow is expected to erode this area of fog
through the evening hours. Confidence in the timing of fog clearing
is low. Short-term guidance indicates that fog could return to KHVR,
but confidence is low and so did not include in TAF. Elsewhere,
skies are clearing this evening behind a departing weather system.
High cloud cover will increase by morning as another weak
disturbance moves into western Montana. Conditions will remain VFR
at all terminals except KCTB and possibly KHVR as highlighted above.
Nutter

&&

.PREV DISCUSSION...
/ISSUED 435 PM MST Wed Dec 17 2014/
Wednesday night through Friday...A rather quiet and cool end to
the work week is expected as no major systems are expected to move
over the area in this time frame. Temperatures will remain near
seasonal values as weak shortwave toughing on Thursday will be
followed by a week shortwave ridge on Friday. The biggest impact
during this time period will be the persistent freezing fog over
parts of Central and North Central Montana. Have extended the
advisory currently in effect until 9 pm for areas around Cut Bank
and Shelby. Westerly winds should develop around 6 pm and
eventual scour out the fog. However, there is a chance that the
nocturnal boundary layer will strengthen the inversion and will
limit any potential for the west winds to move the fog out of the
area until Thursday when a weak shortwave moves through the area.
Widespread moisture is not expected at this time with this
disturbance...however some isolated mountain snow showers are
possible. Suk

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate
that the pattern will then change for Saturday night through
Tuesday. An upper level high pressure ridge will strengthen off
the California coast and a low pressure trough will deepen from
Hudson Bay into the Great Lakes. This will result in Montana being
under a strong northwesterly flow aloft. The models indicate that
the strongest winds aloft will occur Sunday into Sunday night with
the passage of a disturbance embedded in the flow. However, the
models differ on just how strong these winds will be. The ECMWF
only forecasts winds of 45 to 55 kts at 700 mb, while the GFS
generally has 60 to 70 kt winds. Have therefore used a compromise
solution between these two models with regards to surface wind
strength. Despite this difference, this set-up will bring gusty
westerly downslope winds to much of the area, but especially over
the plains of north central Montana. In fact, some areas along the
Rocky Mountain Front could approach High Wind criteria (40 mph
sustained/58 mph gusts). Confidence remains moderate that High
Wind highlights may be needed for this event. The only concern is
that the northwesterly wind direction is not as favorable for
widespread High Winds. There is also significant moisture with
this disturbance, so have continued to spread the chance for
precipitation out onto the plains. Winds aloft will decrease
somewhat after the passage of the disturbance, but the
northwesterly flow aloft will remain fairly moist, so have kept
the chance for precipitation above climatological normals across
the area into Tuesday. A potentially significant weather system
originating in the Gulf of Alaska is then forecast to move into
Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees
above normal. The warmest day of the period appears to be Monday,
when most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly
below seasonal averages by Wednesday. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  25  40  26  40 /  10  10  10  10
CTB  12  39  24  39 /  10  10  10  10
HLN  19  34  19  35 /  10  20  10  20
BZN  14  30  15  32 /  10  10  10  20
WEY  17  32  19  33 /  20  20  30  40
DLN  18  34  19  37 /  10  20  10  20
HVR  16  37  22  39 /  10  10  10  10
LWT  23  43  24  43 /  10  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 9 AM MST Thursday Eastern Glacier...
Eastern Pondera...Eastern Teton...Hill...Liberty...Southern
Rocky Mountain Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 180443
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
943 PM MST Wed Dec 17 2014

.UPDATE...
Latest observations show freezing fog, dense in areas, continuing
over most of the Hiline counties and redeveloping in parts of
Pondera and Teton counties. So have extended the freezing fog
advisory for eastern Glacier and Toole and added eastern Pondera,
Teton, Liberty, and Hill counties to the advisory that now goes
until 9am Thurs. Also adjusted the overnight lows in the fog areas
as several sites were at/below the forecast minimum temps. A weak
shortwave trof currently crossing western MT may help increase the
surface winds east of the Divide during the overnight hours to
help dissipate some of the fog, but confidence is only marginal
for that to occur.
Waranauskas

&&

.AVIATION...
UPDATED 2335Z.
Persistent freezing fog continues at KCTB with LIFR conditions.
Southwesterly downslope flow is expected to erode this area of fog
through the evening hours. Confidence in the timing of fog clearing
is low. Short-term guidance indicates that fog could return to KHVR,
but confidence is low and so did not include in TAF. Elsewhere,
skies are clearing this evening behind a departing weather system.
High cloud cover will increase by morning as another weak
disturbance moves into western Montana. Conditions will remain VFR
at all terminals except KCTB and possibly KHVR as highlighted above.
Nutter

&&

.PREV DISCUSSION...
/ISSUED 435 PM MST Wed Dec 17 2014/
Wednesday night through Friday...A rather quiet and cool end to
the work week is expected as no major systems are expected to move
over the area in this time frame. Temperatures will remain near
seasonal values as weak shortwave toughing on Thursday will be
followed by a week shortwave ridge on Friday. The biggest impact
during this time period will be the persistent freezing fog over
parts of Central and North Central Montana. Have extended the
advisory currently in effect until 9 pm for areas around Cut Bank
and Shelby. Westerly winds should develop around 6 pm and
eventual scour out the fog. However, there is a chance that the
nocturnal boundary layer will strengthen the inversion and will
limit any potential for the west winds to move the fog out of the
area until Thursday when a weak shortwave moves through the area.
Widespread moisture is not expected at this time with this
disturbance...however some isolated mountain snow showers are
possible. Suk

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate
that the pattern will then change for Saturday night through
Tuesday. An upper level high pressure ridge will strengthen off
the California coast and a low pressure trough will deepen from
Hudson Bay into the Great Lakes. This will result in Montana being
under a strong northwesterly flow aloft. The models indicate that
the strongest winds aloft will occur Sunday into Sunday night with
the passage of a disturbance embedded in the flow. However, the
models differ on just how strong these winds will be. The ECMWF
only forecasts winds of 45 to 55 kts at 700 mb, while the GFS
generally has 60 to 70 kt winds. Have therefore used a compromise
solution between these two models with regards to surface wind
strength. Despite this difference, this set-up will bring gusty
westerly downslope winds to much of the area, but especially over
the plains of north central Montana. In fact, some areas along the
Rocky Mountain Front could approach High Wind criteria (40 mph
sustained/58 mph gusts). Confidence remains moderate that High
Wind highlights may be needed for this event. The only concern is
that the northwesterly wind direction is not as favorable for
widespread High Winds. There is also significant moisture with
this disturbance, so have continued to spread the chance for
precipitation out onto the plains. Winds aloft will decrease
somewhat after the passage of the disturbance, but the
northwesterly flow aloft will remain fairly moist, so have kept
the chance for precipitation above climatological normals across
the area into Tuesday. A potentially significant weather system
originating in the Gulf of Alaska is then forecast to move into
Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees
above normal. The warmest day of the period appears to be Monday,
when most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly
below seasonal averages by Wednesday. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  25  40  26  40 /  10  10  10  10
CTB  12  39  24  39 /  10  10  10  10
HLN  19  34  19  35 /  10  20  10  20
BZN  14  30  15  32 /  10  10  10  20
WEY  17  32  19  33 /  20  20  30  40
DLN  18  34  19  37 /  10  20  10  20
HVR  16  37  22  39 /  10  10  10  10
LWT  23  43  24  43 /  10  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 9 AM MST Thursday Eastern Glacier...
Eastern Pondera...Eastern Teton...Hill...Liberty...Southern
Rocky Mountain Front...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 172350
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
435 PM MST Wed Dec 17 2014

Aviation Section Updated.

.DISCUSSION...
Wednesday night through Friday...A rather quiet and cool end to
the work week is expected as no major systems are expected to move
over the area in this time frame. Temperatures will remain near
seasonal values as weak shortwave toughing on Thursday will be
followed by a week shortwave ridge on Friday. The biggest impact
during this time period will be the persistent freezing fog over
parts of Central and North Central Montana. Have extended the
advisory currently in effect until 9 pm for areas around Cut Bank
and Shelby. Westerly winds should develop around 6 pm and
eventual scour out the fog. However, there is a chance that the
nocturnal boundary layer will strengthen the inversion and will
limit any potential for the west winds to move the fog out of the
area until Thursday when a weak shortwave moves through the area.
Widespread moisture is not expected at this time with this
disturbance...however some isolated mountain snow showers are
possible. Suk

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate
that the pattern will then change for Saturday night through
Tuesday. An upper level high pressure ridge will strengthen off
the California coast and a low pressure trough will deepen from
Hudson Bay into the Great Lakes. This will result in Montana being
under a strong northwesterly flow aloft. The models indicate that
the strongest winds aloft will occur Sunday into Sunday night with
the passage of a disturbance embedded in the flow. However, the
models differ on just how strong these winds will be. The ECMWF
only forecasts winds of 45 to 55 kts at 700 mb, while the GFS
generally has 60 to 70 kt winds. Have therefore used a compromise
solution between these two models with regards to surface wind
strength. Despite this difference, this set-up will bring gusty
westerly downslope winds to much of the area, but especially over
the plains of north central Montana. In fact, some areas along the
Rocky Mountain Front could approach High Wind criteria (40 mph
sustained/58 mph gusts). Confidence remains moderate that High
Wind highlights may be needed for this event. The only concern is
that the northwesterly wind direction is not as favorable for
widespread High Winds. There is also significant moisture with
this disturbance, so have continued to spread the chance for
precipitation out onto the plains. Winds aloft will decrease
somewhat after the passage of the disturbance, but the
northwesterly flow aloft will remain fairly moist, so have kept
the chance for precipitation above climatological normals across
the area into Tuesday. A potentially significant weather system
originating in the Gulf of Alaska is then forecast to move into
Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees
above normal. The warmest day of the period appears to be Monday,
when most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly
below seasonal averages by Wednesday. Coulston

&&

.AVIATION...
UPDATED 2335Z.
Persistent freezing fog continues at KCTB with LIFR conditions.
Southwesterly downslope flow is expected to erode this area of fog
through the evening hours. Confidence in the timing of fog clearing
is low. Short-term guidance indicates that fog could return to KHVR,
but confidence is low and so did not include in TAF. Elsewhere,
skies are clearing this evening behind a departing weather system.
High cloud cover will increase by morning as another weak
disturbance moves into western Montana. Conditions will remain VFR
at all terminals except KCTB and possibly KHVR as highlighted above.
Nutter

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  23  40  26  40 /  10  10  10  10
CTB  21  39  24  39 /  10  10  10  10
HLN  18  34  19  35 /  10  20  10  20
BZN  14  30  15  32 /  10  10  10  20
WEY  16  32  19  33 /  20  20  30  40
DLN  17  34  19  37 /  10  20  10  20
HVR  18  37  22  39 /  10  10  10  10
LWT  21  43  24  43 /  10  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 9 PM MST this evening Eastern
Glacier...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls









000
FXUS65 KTFX 172350
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
435 PM MST Wed Dec 17 2014

Aviation Section Updated.

.DISCUSSION...
Wednesday night through Friday...A rather quiet and cool end to
the work week is expected as no major systems are expected to move
over the area in this time frame. Temperatures will remain near
seasonal values as weak shortwave toughing on Thursday will be
followed by a week shortwave ridge on Friday. The biggest impact
during this time period will be the persistent freezing fog over
parts of Central and North Central Montana. Have extended the
advisory currently in effect until 9 pm for areas around Cut Bank
and Shelby. Westerly winds should develop around 6 pm and
eventual scour out the fog. However, there is a chance that the
nocturnal boundary layer will strengthen the inversion and will
limit any potential for the west winds to move the fog out of the
area until Thursday when a weak shortwave moves through the area.
Widespread moisture is not expected at this time with this
disturbance...however some isolated mountain snow showers are
possible. Suk

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate
that the pattern will then change for Saturday night through
Tuesday. An upper level high pressure ridge will strengthen off
the California coast and a low pressure trough will deepen from
Hudson Bay into the Great Lakes. This will result in Montana being
under a strong northwesterly flow aloft. The models indicate that
the strongest winds aloft will occur Sunday into Sunday night with
the passage of a disturbance embedded in the flow. However, the
models differ on just how strong these winds will be. The ECMWF
only forecasts winds of 45 to 55 kts at 700 mb, while the GFS
generally has 60 to 70 kt winds. Have therefore used a compromise
solution between these two models with regards to surface wind
strength. Despite this difference, this set-up will bring gusty
westerly downslope winds to much of the area, but especially over
the plains of north central Montana. In fact, some areas along the
Rocky Mountain Front could approach High Wind criteria (40 mph
sustained/58 mph gusts). Confidence remains moderate that High
Wind highlights may be needed for this event. The only concern is
that the northwesterly wind direction is not as favorable for
widespread High Winds. There is also significant moisture with
this disturbance, so have continued to spread the chance for
precipitation out onto the plains. Winds aloft will decrease
somewhat after the passage of the disturbance, but the
northwesterly flow aloft will remain fairly moist, so have kept
the chance for precipitation above climatological normals across
the area into Tuesday. A potentially significant weather system
originating in the Gulf of Alaska is then forecast to move into
Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees
above normal. The warmest day of the period appears to be Monday,
when most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly
below seasonal averages by Wednesday. Coulston

&&

.AVIATION...
UPDATED 2335Z.
Persistent freezing fog continues at KCTB with LIFR conditions.
Southwesterly downslope flow is expected to erode this area of fog
through the evening hours. Confidence in the timing of fog clearing
is low. Short-term guidance indicates that fog could return to KHVR,
but confidence is low and so did not include in TAF. Elsewhere,
skies are clearing this evening behind a departing weather system.
High cloud cover will increase by morning as another weak
disturbance moves into western Montana. Conditions will remain VFR
at all terminals except KCTB and possibly KHVR as highlighted above.
Nutter

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  23  40  26  40 /  10  10  10  10
CTB  21  39  24  39 /  10  10  10  10
HLN  18  34  19  35 /  10  20  10  20
BZN  14  30  15  32 /  10  10  10  20
WEY  16  32  19  33 /  20  20  30  40
DLN  17  34  19  37 /  10  20  10  20
HVR  18  37  22  39 /  10  10  10  10
LWT  21  43  24  43 /  10  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 9 PM MST this evening Eastern
Glacier...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls








000
FXUS65 KTFX 172122
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
222 PM MST Wed Dec 17 2014

.DISCUSSION...
Wednesday night through Friday...A rather quiet and cool end to
the work week is expected as no major systems are expected to move
over the area in this time frame. Temperatures will remain near
seasonal values as weak shortwave toughing on Thursday will be
followed by a week shortwave ridge on Friday. The biggest impact
during this time period will be the persistent freezing fog over
parts of Central and North Central Montana. Have extended the
advisory currently in effect until 9 pm for areas around Cut Bank
and Shelby. Westerly winds should develop around 6 pm and
eventual scour out the fog. However, there is a chance that the
nocturnal boundary layer will strengthen the inversion and will
limit any potential for the west winds to move the fog out of the
area until Thursday when a weak shortwave moves through the area.
Widespread moisture is not expected at this time with this
disturbance...however some isolated mountain snow showers are
possible. Suk

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate
that the pattern will then change for Saturday night through
Tuesday. An upper level high pressure ridge will strengthen off
the California coast and a low pressure trough will deepen from
Hudson Bay into the Great Lakes. This will result in Montana being
under a strong northwesterly flow aloft. The models indicate that
the strongest winds aloft will occur Sunday into Sunday night with
the passage of a disturbance embedded in the flow. However, the
models differ on just how strong these winds will be. The ECMWF
only forecasts winds of 45 to 55 kts at 700 mb, while the GFS
generally has 60 to 70 kt winds. Have therefore used a compromise
solution between these two models with regards to surface wind
strength. Despite this difference, this set-up will bring gusty
westerly downslope winds to much of the area, but especially over
the plains of north central Montana. In fact, some areas along the
Rocky Mountain Front could approach High Wind criteria (40 mph
sustained/58 mph gusts). Confidence remains moderate that High
Wind highlights may be needed for this event. The only concern is
that the northwesterly wind direction is not as favorable for
widespread High Winds. There is also significant moisture with
this disturbance, so have continued to spread the chance for
precipitation out onto the plains. Winds aloft will decrease
somewhat after the passage of the disturbance, but the
northwesterly flow aloft will remain fairly moist, so have kept
the chance for precipitation above climatological normals across
the area into Tuesday. A potentially significant weather system
originating in the Gulf of Alaska is then forecast to move into
Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees
above normal. The warmest day of the period appears to be Monday,
when most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly
below seasonal averages by Wednesday. Coulston

&&

.AVIATION...
UPDATED 1758Z.
Light snow will be ending at KHVR and KLWT by late afternoon with
conditions improving to VFR. At KCTB LIFR conditions in freezing fog
will also improve to VFR by late afternoon. Local MVFR visibilities
in freezing fog over southwest Montana will end by mid-afternoon.
For tonight through Thursday morning expect scattered snow over the
Rocky Mountain Front. For tonight into early Thursday morning for
KCTB and KLWT some guidance suggests IFR ceilings and/or
visibilities in freezing fog could return but think there will be
enough wind to prevent this from happening so did not mention in
their TAFs. At KHVR IFR ceilings and/or visibilities in freezing fog
could also return but think there is a better chance there relative
to KLWT/KCTB so included in their taf. But some guidance keeps
conditions VFR at KHVR. For late tonight think southwest winds will
dissipate the freezing fog at KHVR but should southwest winds not
develop IFR conditions could linger into Thursday morning.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  23  40  26  40 /  10  10  10  10
CTB  21  39  24  39 /  10  10  10  10
HLN  18  34  19  35 /  10  20  10  20
BZN  14  30  15  32 /  10  10  10  20
WEY  16  32  19  33 /  20  20  30  40
DLN  17  34  19  37 /  10  20  10  20
HVR  18  37  22  39 /  10  10  10  10
LWT  21  43  24  43 /  10  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 9 PM MST this evening Eastern
Glacier...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 171759
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1058 AM MST Wed Dec 17 2014

UPDATED AVIATION DISCUSSION

.UPDATE...
Have continued to decrease the area of the freezing fog advisory.
Have also lowered high temperatures where the freezing fog is
persisting and already keeping locations cooler than previous
forecast. Otherwise no significant changes to the forecast this
morning. Suk


&&

.AVIATION...
UPDATED 1758Z.
Light snow will be ending at KHVR and KLWT by late afternoon with
conditions improving to VFR. At KCTB LIFR conditions in freezing fog
will also improve to VFR by late afternoon. Local MVFR visibilities
in freezing fog over southwest Montana will end by mid-afternoon.
For tonight through Thursday morning expect scattered snow over the
Rocky Mountain Front. For tonight into early Thursday morning for
KCTB and KLWT some guidance suggests IFR ceilings and/or
visibilities in freezing fog could return but think there will be
enough wind to prevent this from happening so did not mention in
their TAFs. At KHVR IFR ceilings and/or visibilities in freezing fog
could also return but think there is a better chance there relative
to KLWT/KCTB so included in their taf. But some guidance keeps
conditions VFR at KHVR. For late tonight think southwest winds will
dissipate the freezing fog at KHVR but should southwest winds not
develop IFR conditions could linger into Thursday morning.

&&

.PREV DISCUSSION...
/ISSUED 807 AM MST Wed Dec 17 2014/
FXUS65 KTFX 171507
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
807 AM MST Wed Dec 17 2014

UPDATE...
Dense freezing fog is no longer expected over Cascade and Judith
Basin Counties so the freezing fog advisory for those counties has
been canceled.

&&

.PREV DISCUSSION...
/ISSUED 510 AM MST Wed Dec 17 2014/

Tonight through Friday...Central Montana is underneath an area of
weak cyclonic flow aloft. Precipitation associated with a
disturbance in this flow will move east of the zones today. A weak
trof over over the Eastern Pacific will move over the Pacific
Northwest today and the zones will be underneath the southwest flow
ahead of this system. Flow aloft and dynamics will remain weak,
however. Models show very little warming of the airmass yet raise
temperatures from yesterday. With cloud cover and, possibly, areas
of fog, not convinced that all of that warming will occur and will
moderate high temps somewhat. The airmass will remain unsettled
Thursday as the trof over the Eastern Pacific slowly moves east and
and approaches the zones. Little chance of precipitation is expected
with this system. The Rockies and mountains of Southwest Montana
will have the best chance for snow although accumulations will
remain low. Zelzer

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate that
the pattern will then change for Saturday night through Tuesday. An
upper level high pressure ridge will strengthen off the California
coast and a low pressure trough will deepen from Hudson Bay into the
Great Lakes. This will result in Montana being under a strong
northwesterly flow aloft. The models indicate that the strongest
winds aloft will occur Sunday into Sunday night with the passage of
a disturbance embedded in the flow. However, the models differ on
just how strong these winds will be. The ECMWF only forecasts winds
of 45 to 55 kts at 700 mb, while the GFS generally has 60 to 70 kt
winds. Have therefore used a compromise solution between these two
models with regards to surface wind strength. Despite this
difference, this set-up will bring gusty westerly downslope winds to
much of the area, but especially over the plains of north central
Montana. In fact, some areas along the Rocky Mountain Front could
approach High Wind criteria (40 mph sustained/58 mph gusts).
Confidence remains moderate that High Wind highlights may be needed
for this event. The only concern is that the northwesterly wind
direction is not as favorable for widespread High Winds. There is
also significant moisture with this disturbance, so have continued
to spread the chance for precipitation out onto the plains. Winds
aloft will decrease somewhat after the passage of the disturbance,
but the northwesterly flow aloft will remain fairly moist, so have
kept the chance for precipitation above climatological normals
across the area into Tuesday. A potentially significant weather
system originating in the Gulf of Alaska is then forecast to move
into Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees above
normal. The warmest day of the period appears to be Monday, when
most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly below
seasonal averages by Wednesday.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  35  24  38  26 /  20  10  10  10
CTB  26  21  37  24 /  10  10  10  10
HLN  33  17  33  19 /  20  10  20  10
BZN  28  12  30  14 /  40  10  10  10
WEY  32  16  30  18 /  30  20  20  20
DLN  31  16  33  19 /  10  10  20  10
HVR  29  19  36  21 /  30  10  10  10
LWT  36  22  41  24 /  40  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Glacier...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls









000
FXUS65 KTFX 171759
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1058 AM MST Wed Dec 17 2014

UPDATED AVIATION DISCUSSION

.UPDATE...
Have continued to decrease the area of the freezing fog advisory.
Have also lowered high temperatures where the freezing fog is
persisting and already keeping locations cooler than previous
forecast. Otherwise no significant changes to the forecast this
morning. Suk


&&

.AVIATION...
UPDATED 1758Z.
Light snow will be ending at KHVR and KLWT by late afternoon with
conditions improving to VFR. At KCTB LIFR conditions in freezing fog
will also improve to VFR by late afternoon. Local MVFR visibilities
in freezing fog over southwest Montana will end by mid-afternoon.
For tonight through Thursday morning expect scattered snow over the
Rocky Mountain Front. For tonight into early Thursday morning for
KCTB and KLWT some guidance suggests IFR ceilings and/or
visibilities in freezing fog could return but think there will be
enough wind to prevent this from happening so did not mention in
their TAFs. At KHVR IFR ceilings and/or visibilities in freezing fog
could also return but think there is a better chance there relative
to KLWT/KCTB so included in their taf. But some guidance keeps
conditions VFR at KHVR. For late tonight think southwest winds will
dissipate the freezing fog at KHVR but should southwest winds not
develop IFR conditions could linger into Thursday morning.

&&

.PREV DISCUSSION...
/ISSUED 807 AM MST Wed Dec 17 2014/
FXUS65 KTFX 171507
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
807 AM MST Wed Dec 17 2014

UPDATE...
Dense freezing fog is no longer expected over Cascade and Judith
Basin Counties so the freezing fog advisory for those counties has
been canceled.

&&

.PREV DISCUSSION...
/ISSUED 510 AM MST Wed Dec 17 2014/

Tonight through Friday...Central Montana is underneath an area of
weak cyclonic flow aloft. Precipitation associated with a
disturbance in this flow will move east of the zones today. A weak
trof over over the Eastern Pacific will move over the Pacific
Northwest today and the zones will be underneath the southwest flow
ahead of this system. Flow aloft and dynamics will remain weak,
however. Models show very little warming of the airmass yet raise
temperatures from yesterday. With cloud cover and, possibly, areas
of fog, not convinced that all of that warming will occur and will
moderate high temps somewhat. The airmass will remain unsettled
Thursday as the trof over the Eastern Pacific slowly moves east and
and approaches the zones. Little chance of precipitation is expected
with this system. The Rockies and mountains of Southwest Montana
will have the best chance for snow although accumulations will
remain low. Zelzer

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate that
the pattern will then change for Saturday night through Tuesday. An
upper level high pressure ridge will strengthen off the California
coast and a low pressure trough will deepen from Hudson Bay into the
Great Lakes. This will result in Montana being under a strong
northwesterly flow aloft. The models indicate that the strongest
winds aloft will occur Sunday into Sunday night with the passage of
a disturbance embedded in the flow. However, the models differ on
just how strong these winds will be. The ECMWF only forecasts winds
of 45 to 55 kts at 700 mb, while the GFS generally has 60 to 70 kt
winds. Have therefore used a compromise solution between these two
models with regards to surface wind strength. Despite this
difference, this set-up will bring gusty westerly downslope winds to
much of the area, but especially over the plains of north central
Montana. In fact, some areas along the Rocky Mountain Front could
approach High Wind criteria (40 mph sustained/58 mph gusts).
Confidence remains moderate that High Wind highlights may be needed
for this event. The only concern is that the northwesterly wind
direction is not as favorable for widespread High Winds. There is
also significant moisture with this disturbance, so have continued
to spread the chance for precipitation out onto the plains. Winds
aloft will decrease somewhat after the passage of the disturbance,
but the northwesterly flow aloft will remain fairly moist, so have
kept the chance for precipitation above climatological normals
across the area into Tuesday. A potentially significant weather
system originating in the Gulf of Alaska is then forecast to move
into Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees above
normal. The warmest day of the period appears to be Monday, when
most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly below
seasonal averages by Wednesday.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  35  24  38  26 /  20  10  10  10
CTB  26  21  37  24 /  10  10  10  10
HLN  33  17  33  19 /  20  10  20  10
BZN  28  12  30  14 /  40  10  10  10
WEY  32  16  30  18 /  30  20  20  20
DLN  31  16  33  19 /  10  10  20  10
HVR  29  19  36  21 /  30  10  10  10
LWT  36  22  41  24 /  40  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Glacier...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls








000
FXUS65 KTFX 171654
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
954 AM MST Wed Dec 17 2014

.UPDATE...
Have continued to decrease the area of the freezing fog advisory.
Have also lowered high temperatures where the freezing fog is
persisting and already keeping locations cooler than previous
forecast. Otherwise no significant changes to the forecast this
morning. Suk


&&

.AVIATION...
UPDATED 1209Z.
Light snow has ended across most of Central Montana although
northeastern portions, near and east of KHVR and KLWT, continue to
see light snow. Winds will remain light today and areas of fog, and
some dense freezing fog along northern portions of the region, will
continue into the morning. Widespread IFR conditions will continue
into late morning near KCTB.

&&

.PREV DISCUSSION...
/ISSUED 807 AM MST Wed Dec 17 2014/
FXUS65 KTFX 171507
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
807 AM MST Wed Dec 17 2014

UPDATE...
Dense freezing fog is no longer expected over Cascade and Judith
Basin Counties so the freezing fog advisory for those counties has
been canceled.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  35  24  38  26 /  20  10  10  10
CTB  26  21  37  24 /  10  10  10  10
HLN  33  17  33  19 /  20  10  20  10
BZN  28  12  30  14 /  40  10  10  10
WEY  32  16  30  18 /  30  20  20  20
DLN  31  16  33  19 /  10  10  20  10
HVR  29  19  36  21 /  30  10  10  10
LWT  36  22  41  24 /  40  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Glacier...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 171654
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
954 AM MST Wed Dec 17 2014

.UPDATE...
Have continued to decrease the area of the freezing fog advisory.
Have also lowered high temperatures where the freezing fog is
persisting and already keeping locations cooler than previous
forecast. Otherwise no significant changes to the forecast this
morning. Suk


&&

.AVIATION...
UPDATED 1209Z.
Light snow has ended across most of Central Montana although
northeastern portions, near and east of KHVR and KLWT, continue to
see light snow. Winds will remain light today and areas of fog, and
some dense freezing fog along northern portions of the region, will
continue into the morning. Widespread IFR conditions will continue
into late morning near KCTB.

&&

.PREV DISCUSSION...
/ISSUED 807 AM MST Wed Dec 17 2014/
FXUS65 KTFX 171507
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
807 AM MST Wed Dec 17 2014

UPDATE...
Dense freezing fog is no longer expected over Cascade and Judith
Basin Counties so the freezing fog advisory for those counties has
been canceled.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  35  24  38  26 /  20  10  10  10
CTB  26  21  37  24 /  10  10  10  10
HLN  33  17  33  19 /  20  10  20  10
BZN  28  12  30  14 /  40  10  10  10
WEY  32  16  30  18 /  30  20  20  20
DLN  31  16  33  19 /  10  10  20  10
HVR  29  19  36  21 /  30  10  10  10
LWT  36  22  41  24 /  40  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Glacier...Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 171507
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
807 AM MST Wed Dec 17 2014

.UPDATE...
Dense freezing fog is no longer expected over Cascade and Judith
Basin Counties so the freezing fog advisory for those counties has
been cancelled.

&&

.AVIATION...
UPDATED 1209Z.
Light snow has ended across most of Central Montana although
northeastern portions, near and east of KHVR and KLWT, continue to
see light snow. Winds will remain light today and areas of fog, and
some dense freezing fog along northern portions of the region, will
continue into the morning. Widespread IFR conditions will continue
into late morning near KCTB.

&&

.PREV DISCUSSION...
/ISSUED 510 AM MST Wed Dec 17 2014/

Tonight through Friday...Central Montana is underneath an area of
weak cyclonic flow aloft. Precipitation associated with a
disturbance in this flow will move east of the zones today. A weak
trof over over the Eastern Pacific will move over the Pacific
Northwest today and the zones will be underneath the southwest flow
ahead of this system. Flow aloft and dynamics will remain weak,
however. Models show very little warming of the airmass yet raise
temperatures from yesterday. With cloud cover and, possibly, areas
of fog, not convinced that all of that warming will occur and will
moderate high temps somewhat. The airmass will remain unsettled
Thursday as the trof over the Eastern Pacific slowly moves east and
and approaches the zones. Little chance of precipitation is expected
with this system. The Rockies and mountains of Southwest Montana
will have the best chance for snow although accumulations will
remain low. Zelzer

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate that
the pattern will then change for Saturday night through Tuesday. An
upper level high pressure ridge will strengthen off the California
coast and a low pressure trough will deepen from Hudson Bay into the
Great Lakes. This will result in Montana being under a strong
northwesterly flow aloft. The models indicate that the strongest
winds aloft will occur Sunday into Sunday night with the passage of
a disturbance embedded in the flow. However, the models differ on
just how strong these winds will be. The ECMWF only forecasts winds
of 45 to 55 kts at 700 mb, while the GFS generally has 60 to 70 kt
winds. Have therefore used a compromise solution between these two
models with regards to surface wind strength. Despite this
difference, this set-up will bring gusty westerly downslope winds to
much of the area, but especially over the plains of north central
Montana. In fact, some areas along the Rocky Mountain Front could
approach High Wind criteria (40 mph sustained/58 mph gusts).
Confidence remains moderate that High Wind highlights may be needed
for this event. The only concern is that the northwesterly wind
direction is not as favorable for widespread High Winds. There is
also significant moisture with this disturbance, so have continued
to spread the chance for precipitation out onto the plains. Winds
aloft will decrease somewhat after the passage of the disturbance,
but the northwesterly flow aloft will remain fairly moist, so have
kept the chance for precipitation above climatological normals
across the area into Tuesday. A potentially significant weather
system originating in the Gulf of Alaska is then forecast to move
into Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees above
normal. The warmest day of the period appears to be Monday, when
most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly below
seasonal averages by Wednesday.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  35  24  38  26 /  20  10  10  10
CTB  32  21  37  24 /  10  10  10  10
HLN  33  17  33  19 /  20  10  20  10
BZN  28  12  30  14 /  40  10  10  10
WEY  32  16  30  18 /  30  20  20  20
DLN  31  16  33  19 /  10  10  20  10
HVR  29  19  36  21 /  30  10  10  10
LWT  36  22  41  24 /  40  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Teton...Southern Rocky Mountain Front.

FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Glacier...Eastern Pondera...Northern Rocky Mountain Front...
Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






000
FXUS65 KTFX 171507
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
807 AM MST Wed Dec 17 2014

.UPDATE...
Dense freezing fog is no longer expected over Cascade and Judith
Basin Counties so the freezing fog advisory for those counties has
been cancelled.

&&

.AVIATION...
UPDATED 1209Z.
Light snow has ended across most of Central Montana although
northeastern portions, near and east of KHVR and KLWT, continue to
see light snow. Winds will remain light today and areas of fog, and
some dense freezing fog along northern portions of the region, will
continue into the morning. Widespread IFR conditions will continue
into late morning near KCTB.

&&

.PREV DISCUSSION...
/ISSUED 510 AM MST Wed Dec 17 2014/

Tonight through Friday...Central Montana is underneath an area of
weak cyclonic flow aloft. Precipitation associated with a
disturbance in this flow will move east of the zones today. A weak
trof over over the Eastern Pacific will move over the Pacific
Northwest today and the zones will be underneath the southwest flow
ahead of this system. Flow aloft and dynamics will remain weak,
however. Models show very little warming of the airmass yet raise
temperatures from yesterday. With cloud cover and, possibly, areas
of fog, not convinced that all of that warming will occur and will
moderate high temps somewhat. The airmass will remain unsettled
Thursday as the trof over the Eastern Pacific slowly moves east and
and approaches the zones. Little chance of precipitation is expected
with this system. The Rockies and mountains of Southwest Montana
will have the best chance for snow although accumulations will
remain low. Zelzer

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate that
the pattern will then change for Saturday night through Tuesday. An
upper level high pressure ridge will strengthen off the California
coast and a low pressure trough will deepen from Hudson Bay into the
Great Lakes. This will result in Montana being under a strong
northwesterly flow aloft. The models indicate that the strongest
winds aloft will occur Sunday into Sunday night with the passage of
a disturbance embedded in the flow. However, the models differ on
just how strong these winds will be. The ECMWF only forecasts winds
of 45 to 55 kts at 700 mb, while the GFS generally has 60 to 70 kt
winds. Have therefore used a compromise solution between these two
models with regards to surface wind strength. Despite this
difference, this set-up will bring gusty westerly downslope winds to
much of the area, but especially over the plains of north central
Montana. In fact, some areas along the Rocky Mountain Front could
approach High Wind criteria (40 mph sustained/58 mph gusts).
Confidence remains moderate that High Wind highlights may be needed
for this event. The only concern is that the northwesterly wind
direction is not as favorable for widespread High Winds. There is
also significant moisture with this disturbance, so have continued
to spread the chance for precipitation out onto the plains. Winds
aloft will decrease somewhat after the passage of the disturbance,
but the northwesterly flow aloft will remain fairly moist, so have
kept the chance for precipitation above climatological normals
across the area into Tuesday. A potentially significant weather
system originating in the Gulf of Alaska is then forecast to move
into Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees above
normal. The warmest day of the period appears to be Monday, when
most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly below
seasonal averages by Wednesday.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  35  24  38  26 /  20  10  10  10
CTB  32  21  37  24 /  10  10  10  10
HLN  33  17  33  19 /  20  10  20  10
BZN  28  12  30  14 /  40  10  10  10
WEY  32  16  30  18 /  30  20  20  20
DLN  31  16  33  19 /  10  10  20  10
HVR  29  19  36  21 /  30  10  10  10
LWT  36  22  41  24 /  40  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Teton...Southern Rocky Mountain Front.

FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Glacier...Eastern Pondera...Northern Rocky Mountain Front...
Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 171210
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
510 AM MST Wed Dec 17 2014

.DISCUSSION...

Tonight through Friday...Central Montana is underneath an area of
weak cyclonic flow aloft. Precipitation associated with a
disturbance in this flow will move east of the zones today. A weak
trof over over the Eastern Pacific will move over the Pacific
Northwest today and the zones will be underneath the southwest flow
ahead of this system. Flow aloft and dynamics will remain weak,
however. Models show very little warming of the airmass yet raise
temperatures from yesterday. With cloud cover and, possibly, areas
of fog, not convinced that all of that warming will occur and will
moderate high temps somewhat. The airmass will remain unsettled
Thursday as the trof over the Eastern Pacific slowly moves east and
and approaches the zones. Little chance of precipitation is expected
with this system. The Rockies and mountains of Southwest Montana
will have the best chance for snow although accumulations will
remain low. Zelzer

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate that
the pattern will then change for Saturday night through Tuesday. An
upper level high pressure ridge will strengthen off the California
coast and a low pressure trough will deepen from Hudson Bay into the
Great Lakes. This will result in Montana being under a strong
northwesterly flow aloft. The models indicate that the strongest
winds aloft will occur Sunday into Sunday night with the passage of
a disturbance embedded in the flow. However, the models differ on
just how strong these winds will be. The ECMWF only forecasts winds
of 45 to 55 kts at 700 mb, while the GFS generally has 60 to 70 kt
winds. Have therefore used a compromise solution between these two
models with regards to surface wind strength. Despite this
difference, this set-up will bring gusty westerly downslope winds to
much of the area, but especially over the plains of north central
Montana. In fact, some areas along the Rocky Mountain Front could
approach High Wind criteria (40 mph sustained/58 mph gusts).
Confidence remains moderate that High Wind highlights may be needed
for this event. The only concern is that the northwesterly wind
direction is not as favorable for widespread High Winds. There is
also significant moisture with this disturbance, so have continued
to spread the chance for precipitation out onto the plains. Winds
aloft will decrease somewhat after the passage of the disturbance,
but the northwesterly flow aloft will remain fairly moist, so have
kept the chance for precipitation above climatological normals
across the area into Tuesday. A potentially significant weather
system originating in the Gulf of Alaska is then forecast to move
into Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees above
normal. The warmest day of the period appears to be Monday, when
most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly below
seasonal averages by Wednesday.
Coulston

&&

.AVIATION...
UPDATED 1209Z.
Light snow has ended across most of Central Montana although
northeastern portions, near and east of KHVR and KLWT, continue to
see light snow. Winds will remain light today and areas of fog, and
some dense freezing fog along northern portions of the region, will
continue into the morning. Widespread IFR conditions will continue
into late morning near KCTB.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  35  24  38  26 /  20  10  10  10
CTB  32  21  37  24 /  10  10  10  10
HLN  33  17  33  19 /  20  10  20  10
BZN  28  12  30  14 /  40  10  10  10
WEY  32  16  30  18 /  30  20  20  20
DLN  31  16  33  19 /  10  10  20  10
HVR  29  19  36  21 /  30  10  10  10
LWT  36  22  41  24 /  40  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Cascade...
Eastern Teton...Judith Basin...Southern Rocky Mountain Front.

FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Glacier...Eastern Pondera...Northern Rocky Mountain Front...
Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls








000
FXUS65 KTFX 171210
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
510 AM MST Wed Dec 17 2014

.DISCUSSION...

Tonight through Friday...Central Montana is underneath an area of
weak cyclonic flow aloft. Precipitation associated with a
disturbance in this flow will move east of the zones today. A weak
trof over over the Eastern Pacific will move over the Pacific
Northwest today and the zones will be underneath the southwest flow
ahead of this system. Flow aloft and dynamics will remain weak,
however. Models show very little warming of the airmass yet raise
temperatures from yesterday. With cloud cover and, possibly, areas
of fog, not convinced that all of that warming will occur and will
moderate high temps somewhat. The airmass will remain unsettled
Thursday as the trof over the Eastern Pacific slowly moves east and
and approaches the zones. Little chance of precipitation is expected
with this system. The Rockies and mountains of Southwest Montana
will have the best chance for snow although accumulations will
remain low. Zelzer

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate that
the pattern will then change for Saturday night through Tuesday. An
upper level high pressure ridge will strengthen off the California
coast and a low pressure trough will deepen from Hudson Bay into the
Great Lakes. This will result in Montana being under a strong
northwesterly flow aloft. The models indicate that the strongest
winds aloft will occur Sunday into Sunday night with the passage of
a disturbance embedded in the flow. However, the models differ on
just how strong these winds will be. The ECMWF only forecasts winds
of 45 to 55 kts at 700 mb, while the GFS generally has 60 to 70 kt
winds. Have therefore used a compromise solution between these two
models with regards to surface wind strength. Despite this
difference, this set-up will bring gusty westerly downslope winds to
much of the area, but especially over the plains of north central
Montana. In fact, some areas along the Rocky Mountain Front could
approach High Wind criteria (40 mph sustained/58 mph gusts).
Confidence remains moderate that High Wind highlights may be needed
for this event. The only concern is that the northwesterly wind
direction is not as favorable for widespread High Winds. There is
also significant moisture with this disturbance, so have continued
to spread the chance for precipitation out onto the plains. Winds
aloft will decrease somewhat after the passage of the disturbance,
but the northwesterly flow aloft will remain fairly moist, so have
kept the chance for precipitation above climatological normals
across the area into Tuesday. A potentially significant weather
system originating in the Gulf of Alaska is then forecast to move
into Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees above
normal. The warmest day of the period appears to be Monday, when
most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly below
seasonal averages by Wednesday.
Coulston

&&

.AVIATION...
UPDATED 1209Z.
Light snow has ended across most of Central Montana although
northeastern portions, near and east of KHVR and KLWT, continue to
see light snow. Winds will remain light today and areas of fog, and
some dense freezing fog along northern portions of the region, will
continue into the morning. Widespread IFR conditions will continue
into late morning near KCTB.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  35  24  38  26 /  20  10  10  10
CTB  32  21  37  24 /  10  10  10  10
HLN  33  17  33  19 /  20  10  20  10
BZN  28  12  30  14 /  40  10  10  10
WEY  32  16  30  18 /  30  20  20  20
DLN  31  16  33  19 /  10  10  20  10
HVR  29  19  36  21 /  30  10  10  10
LWT  36  22  41  24 /  40  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Cascade...
Eastern Teton...Judith Basin...Southern Rocky Mountain Front.

FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Glacier...Eastern Pondera...Northern Rocky Mountain Front...
Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls









000
FXUS65 KTFX 171032
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
332 AM MST Wed Dec 17 2014

.DISCUSSION...

Tonight through Friday...Central Montana is underneath an area of
weak cyclonic flow aloft. Precipitation associated with a
disturbance in this flow will move east of the zones today. A weak
trof over over the Eastern Pacific will move over the Pacific
Northwest today and the zones will be underneath the southwest flow
ahead of this system. Flow aloft and dynamics will remain weak,
however. Models show very little warming of the airmass yet raise
temperatures from yesterday. With cloud cover and, possibly, areas
of fog, not convinced that all of that warming will occur and will
moderate high temps somewhat. The airmass will remain unsettled
Thursday as the trof over the Eastern Pacific slowly moves east and
and approaches the zones. Little chance of precipitation is expected
with this system. The Rockies and mountains of Southwest Montana
will have the best chance for snow although accumulations will
remain low. Zelzer

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate that
the pattern will then change for Saturday night through Tuesday. An
upper level high pressure ridge will strengthen off the California
coast and a low pressure trough will deepen from Hudson Bay into the
Great Lakes. This will result in Montana being under a strong
northwesterly flow aloft. The models indicate that the strongest
winds aloft will occur Sunday into Sunday night with the passage of
a disturbance embedded in the flow. However, the models differ on
just how strong these winds will be. The ECMWF only forecasts winds
of 45 to 55 kts at 700 mb, while the GFS generally has 60 to 70 kt
winds. Have therefore used a compromise solution between these two
models with regards to surface wind strength. Despite this
difference, this set-up will bring gusty westerly downslope winds to
much of the area, but especially over the plains of north central
Montana. In fact, some areas along the Rocky Mountain Front could
approach High Wind criteria (40 mph sustained/58 mph gusts).
Confidence remains moderate that High Wind highlights may be needed
for this event. The only concern is that the northwesterly wind
direction is not as favorable for widespread High Winds. There is
also significant moisture with this disturbance, so have continued
to spread the chance for precipitation out onto the plains. Winds
aloft will decrease somewhat after the passage of the disturbance,
but the northwesterly flow aloft will remain fairly moist, so have
kept the chance for precipitation above climatological normals
across the area into Tuesday. A potentially significant weather
system originating in the Gulf of Alaska is then forecast to move
into Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees above
normal. The warmest day of the period appears to be Monday, when
most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly below
seasonal averages by Wednesday.
Coulston

&&

.AVIATION...
UPDATED 0545Z.
Light snow continues to push northward from Southwest MT into
Central MT. Expect visibilities to generally be 2SM in areas of snow
along with mountains obscured. There is only a small chance the snow
will make into the Great Falls and Havre areas. Areas of dense fog
will continue to affect the Cut Bank area until Wednesday morning.
Expect VFR conditions to develop over much of the region on
Wednesday afternoon...as southwesterly winds start to develop. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  35  24  38  26 /  20  10  10  10
CTB  32  21  37  24 /  10  10  10  10
HLN  33  17  33  19 /  20  10  20  10
BZN  28  12  30  14 /  40  10  10  10
WEY  32  16  30  18 /  30  20  20  20
DLN  31  16  33  19 /  10  10  20  10
HVR  29  19  36  21 /  30  10  10  10
LWT  36  22  41  24 /  40  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Cascade...
Eastern Teton...Judith Basin...Southern Rocky Mountain Front.

FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Glacier...Eastern Pondera...Northern Rocky Mountain Front...
Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls







000
FXUS65 KTFX 171032
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
332 AM MST Wed Dec 17 2014

.DISCUSSION...

Tonight through Friday...Central Montana is underneath an area of
weak cyclonic flow aloft. Precipitation associated with a
disturbance in this flow will move east of the zones today. A weak
trof over over the Eastern Pacific will move over the Pacific
Northwest today and the zones will be underneath the southwest flow
ahead of this system. Flow aloft and dynamics will remain weak,
however. Models show very little warming of the airmass yet raise
temperatures from yesterday. With cloud cover and, possibly, areas
of fog, not convinced that all of that warming will occur and will
moderate high temps somewhat. The airmass will remain unsettled
Thursday as the trof over the Eastern Pacific slowly moves east and
and approaches the zones. Little chance of precipitation is expected
with this system. The Rockies and mountains of Southwest Montana
will have the best chance for snow although accumulations will
remain low. Zelzer

Friday Night through Wednesday...A weak shortwave trough will move
through Montana Friday night into Saturday, bringing just a chance
of snow to the mountains. Forecast models continue to indicate that
the pattern will then change for Saturday night through Tuesday. An
upper level high pressure ridge will strengthen off the California
coast and a low pressure trough will deepen from Hudson Bay into the
Great Lakes. This will result in Montana being under a strong
northwesterly flow aloft. The models indicate that the strongest
winds aloft will occur Sunday into Sunday night with the passage of
a disturbance embedded in the flow. However, the models differ on
just how strong these winds will be. The ECMWF only forecasts winds
of 45 to 55 kts at 700 mb, while the GFS generally has 60 to 70 kt
winds. Have therefore used a compromise solution between these two
models with regards to surface wind strength. Despite this
difference, this set-up will bring gusty westerly downslope winds to
much of the area, but especially over the plains of north central
Montana. In fact, some areas along the Rocky Mountain Front could
approach High Wind criteria (40 mph sustained/58 mph gusts).
Confidence remains moderate that High Wind highlights may be needed
for this event. The only concern is that the northwesterly wind
direction is not as favorable for widespread High Winds. There is
also significant moisture with this disturbance, so have continued
to spread the chance for precipitation out onto the plains. Winds
aloft will decrease somewhat after the passage of the disturbance,
but the northwesterly flow aloft will remain fairly moist, so have
kept the chance for precipitation above climatological normals
across the area into Tuesday. A potentially significant weather
system originating in the Gulf of Alaska is then forecast to move
into Montana Tuesday into Wednesday, bringing a very good chance of
precipitation. Because this feature is near the end of the period,
exact timing and types of precipitation are very uncertain.
Regardless, this system will need to be monitored for potential
winter weather highlights, especially considering that it would be
moving into the area during peak holiday travel time. The breezy
winds through Monday will keep temperatures around 10 degrees above
normal. The warmest day of the period appears to be Monday, when
most lower elevation locations should get well into the 40s.
However, with the system moving into the area at the end of the
period, temperatures will likely fall back to near or slightly below
seasonal averages by Wednesday.
Coulston

&&

.AVIATION...
UPDATED 0545Z.
Light snow continues to push northward from Southwest MT into
Central MT. Expect visibilities to generally be 2SM in areas of snow
along with mountains obscured. There is only a small chance the snow
will make into the Great Falls and Havre areas. Areas of dense fog
will continue to affect the Cut Bank area until Wednesday morning.
Expect VFR conditions to develop over much of the region on
Wednesday afternoon...as southwesterly winds start to develop. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  35  24  38  26 /  20  10  10  10
CTB  32  21  37  24 /  10  10  10  10
HLN  33  17  33  19 /  20  10  20  10
BZN  28  12  30  14 /  40  10  10  10
WEY  32  16  30  18 /  30  20  20  20
DLN  31  16  33  19 /  10  10  20  10
HVR  29  19  36  21 /  30  10  10  10
LWT  36  22  41  24 /  40  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 11 AM MST this morning Cascade...
Eastern Teton...Judith Basin...Southern Rocky Mountain Front.

FREEZING FOG ADVISORY until 11 AM MST this morning Eastern
Glacier...Eastern Pondera...Northern Rocky Mountain Front...
Toole.

&&

$$

weather.gov/greatfalls
www.twitter.com/NWSGreatFalls
www.facebook.com/NWSGreatFalls






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