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000
FXUS66 KSTO 201109
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
409 AM PDT Mon Oct 20 2014

.Synopsis...
Frontal system will provide cooler temperatures and precipitation
chances from this morning through tonight. Another storm system
will cause shower chances from Wednesday into the weekend.

&&

.Discussion...
At 3 am, radar was showing the main rainband of the incoming front
impacting the NorCal coastline. This rainband has a fairly north
to south orientation with the leading edge along the
Humboldt/Trinity county border and extending northward past Medford,
OR.

For our CWA, expect precipitation to cover the Coastal Range early
this morning (by 5-6 am). The front will continue to track
eastward today spreading chances of precipitation east and
south across interior NorCal. Redding area should start to get rain
around 10-11 am and the Sac metro region around 11 am to noon.
Valley rain amounts won`t amount to much with the Sacramento area
getting a few hundredths and the Northern Sacramento valley
(Redding/Red Bluff vicinity) ranging 0.05" to 0.15". Higher
terrain surrounding the Northern Sac Valley will see higher
amounts of rain measuring around 0.25-0.5"...not "drought-busting"
rain totals, but still helpful.

Once the main rain band passes there could be a slight chance of
convection this afternoon into early evening. Infrared satellite
imagery shows the typical "popcorn" clouds behind the front. This
colder airmass aloft will move over our CWA later today and
enhance instability which could trigger a few thunderstorms. With
the colder air moving inland, daytime highs will range about 3 to
10 degrees below normal. Expect valley highs in the upper 60s to
mid 70s and mountain highs in the 50s & 60s.

Zonal flow aloft over the region for Tuesday with light northerly
winds. Cooler air will remain over the area to keep temperatures
in the lower to mid 70s for another day for the valley to the 50s
for the mountains. Some high cloudiness should be over the area as
well.  JBB



.Extended Discussion (Friday through Monday)

The next main weather impact will be a large low that develops in
the Gulf of Alaska by Wednesday and impacts our region into the
weekend. Rain chances should nudge into the Coastal Range late
Wednesday night with light rain that will spread farther inland at
times for the rest of the week. For Thursday, rain chances will
stay generally north of Interstate 80. Main change from previous
forecasts is that the models are in better agreement as to our wet
weather outlook for the end of the week. From Friday into
Saturday, that low in the Gulf of Alaska will dig southward and
move into the west coast which should spread chances of rain
across all of our CWA into the San Joaquin valley so have
increased PoPs to reflect this. This trough will push eastward on
Sunday and Monday. There will still be lingering chances of rain,
but they will be diminished in areal coverage and be limited to
areas north of I-80 and mainly across higher terrain. Daytime
highs in the extended period will be fairly consistent at near
seasonal to about 5 degrees below normal. JBB


&&

.Aviation...

Generally VFR conditions today with lowering clouds and stronger
southerly winds as a cold front moves through the area today.
Precipitation and lower clouds over the coastal mountains will
spread inland extending over the northern Sacramento Valley by
around 15 z, bringing local MVFR conditions there. MVFR
conditions with local IFR are possible over the Mountains. ISOLD
TSRA possible this afternoon and evening. EK


&&

.STO Watches/Warnings/Advisories...
None.
&&

$$









000
FXUS66 KSTO 201109
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
409 AM PDT Mon Oct 20 2014

.Synopsis...
Frontal system will provide cooler temperatures and precipitation
chances from this morning through tonight. Another storm system
will cause shower chances from Wednesday into the weekend.

&&

.Discussion...
At 3 am, radar was showing the main rainband of the incoming front
impacting the NorCal coastline. This rainband has a fairly north
to south orientation with the leading edge along the
Humboldt/Trinity county border and extending northward past Medford,
OR.

For our CWA, expect precipitation to cover the Coastal Range early
this morning (by 5-6 am). The front will continue to track
eastward today spreading chances of precipitation east and
south across interior NorCal. Redding area should start to get rain
around 10-11 am and the Sac metro region around 11 am to noon.
Valley rain amounts won`t amount to much with the Sacramento area
getting a few hundredths and the Northern Sacramento valley
(Redding/Red Bluff vicinity) ranging 0.05" to 0.15". Higher
terrain surrounding the Northern Sac Valley will see higher
amounts of rain measuring around 0.25-0.5"...not "drought-busting"
rain totals, but still helpful.

Once the main rain band passes there could be a slight chance of
convection this afternoon into early evening. Infrared satellite
imagery shows the typical "popcorn" clouds behind the front. This
colder airmass aloft will move over our CWA later today and
enhance instability which could trigger a few thunderstorms. With
the colder air moving inland, daytime highs will range about 3 to
10 degrees below normal. Expect valley highs in the upper 60s to
mid 70s and mountain highs in the 50s & 60s.

Zonal flow aloft over the region for Tuesday with light northerly
winds. Cooler air will remain over the area to keep temperatures
in the lower to mid 70s for another day for the valley to the 50s
for the mountains. Some high cloudiness should be over the area as
well.  JBB



.Extended Discussion (Friday through Monday)

The next main weather impact will be a large low that develops in
the Gulf of Alaska by Wednesday and impacts our region into the
weekend. Rain chances should nudge into the Coastal Range late
Wednesday night with light rain that will spread farther inland at
times for the rest of the week. For Thursday, rain chances will
stay generally north of Interstate 80. Main change from previous
forecasts is that the models are in better agreement as to our wet
weather outlook for the end of the week. From Friday into
Saturday, that low in the Gulf of Alaska will dig southward and
move into the west coast which should spread chances of rain
across all of our CWA into the San Joaquin valley so have
increased PoPs to reflect this. This trough will push eastward on
Sunday and Monday. There will still be lingering chances of rain,
but they will be diminished in areal coverage and be limited to
areas north of I-80 and mainly across higher terrain. Daytime
highs in the extended period will be fairly consistent at near
seasonal to about 5 degrees below normal. JBB


&&

.Aviation...

Generally VFR conditions today with lowering clouds and stronger
southerly winds as a cold front moves through the area today.
Precipitation and lower clouds over the coastal mountains will
spread inland extending over the northern Sacramento Valley by
around 15 z, bringing local MVFR conditions there. MVFR
conditions with local IFR are possible over the Mountains. ISOLD
TSRA possible this afternoon and evening. EK


&&

.STO Watches/Warnings/Advisories...
None.
&&

$$








000
FXUS66 KSTO 200452
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
952 PM PDT Sun Oct 19 2014

.Synopsis...
Frontal system will provide cooler temperatures and precipitation
chances Monday and Monday night. Another storm system will cause
shower chances mainly for northern areas late in the week.

&&

.Discussion...
Clear skies over Norcal this evening between trough approaching the
coast and high pressure over the Great Basin. Rain band with
frontal system will move into northwest California overnight...but
not reach the coastal range until early morning...Redding area
after 10 am and Sac metro during the afternoon. Current
temperatures are very similar to yesterday at this time. Current
forecast is on track and no evening update will be needed.

.Previous Discussion...
Ridge of high pressure will shift eastward overnight. A weak cold
front will move into the coastal range Monday morning and spread
through the interior during the day. The southern end of the front
will move through Sacramento during the afternoon hours. The front
this far south appears like it wont hold together but may bring
some showers this far south. Further north looks like the better
changes of rain. The central core of the low will move through the
interior Monday evening to keep a threat of showers in the
forecast. Once the low moves into the Great Basin more stable air
will filter in behind the system. Instability does not look that
great with this system but any thunderstorms would likely be
limited to the evening hours as the core of the low moves inland
and probably not that widespread.

Zonal flow aloft over the region for Tuesday with light northerly
winds. Cooler air will remain over the area to keep temperatures
in the lower to mid 70s for another day for the valley to the 50s
for the mountains. Some high cloudiness should be over the area
as well.

A large low will form in the Gulf of Alaska by Wednesday.
By Wednesday night some light rain may spread at times across the
far northern interior areas around Shasta county otherwise expect
dry conditions to prevail for most everyone.



.Extended Discussion (Thursday through Sunday)

A trough over the Eastern Pacific and onto the West Coast for the
later part of the week. There is still low confidence in the
extended forecast due to the models varying with the timing and
strength of waves and the trough moving onto the West Coast. The
GFS is still wetter and more progressive than the ECMWF and moves
the trough through on Saturday. The forecast leans more to the
GFS with the threat of precipitation mainly over the Northern
Sacramento valley and surrounding mountains as weak waves may
brush by the north and as the trough moves inland. Temperatures
are expected to remain near to a little above normal with highs in
the mid 70s to low 80s in the Valley and 50s and 60s in the
mountains on Thursday and Friday then a little cooling over the
weekend with the trough moving inland.


&&

.Aviation...

Generally VFR conditions tonight with increasing clouds and stronger
southerly winds aft 12z as front moves through the area Monday.
Clouds and precipitation may being local MVFR conditions in the
Valley and MVFR conditions with local IFR over the Mountains after
12z Monday. ISOLD TSRA possible Monday afternoon and evening.


&&

.STO Watches/Warnings/Advisories...
None.
&&

$$








000
FXUS66 KSTO 200452
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
952 PM PDT Sun Oct 19 2014

.Synopsis...
Frontal system will provide cooler temperatures and precipitation
chances Monday and Monday night. Another storm system will cause
shower chances mainly for northern areas late in the week.

&&

.Discussion...
Clear skies over Norcal this evening between trough approaching the
coast and high pressure over the Great Basin. Rain band with
frontal system will move into northwest California overnight...but
not reach the coastal range until early morning...Redding area
after 10 am and Sac metro during the afternoon. Current
temperatures are very similar to yesterday at this time. Current
forecast is on track and no evening update will be needed.

.Previous Discussion...
Ridge of high pressure will shift eastward overnight. A weak cold
front will move into the coastal range Monday morning and spread
through the interior during the day. The southern end of the front
will move through Sacramento during the afternoon hours. The front
this far south appears like it wont hold together but may bring
some showers this far south. Further north looks like the better
changes of rain. The central core of the low will move through the
interior Monday evening to keep a threat of showers in the
forecast. Once the low moves into the Great Basin more stable air
will filter in behind the system. Instability does not look that
great with this system but any thunderstorms would likely be
limited to the evening hours as the core of the low moves inland
and probably not that widespread.

Zonal flow aloft over the region for Tuesday with light northerly
winds. Cooler air will remain over the area to keep temperatures
in the lower to mid 70s for another day for the valley to the 50s
for the mountains. Some high cloudiness should be over the area
as well.

A large low will form in the Gulf of Alaska by Wednesday.
By Wednesday night some light rain may spread at times across the
far northern interior areas around Shasta county otherwise expect
dry conditions to prevail for most everyone.



.Extended Discussion (Thursday through Sunday)

A trough over the Eastern Pacific and onto the West Coast for the
later part of the week. There is still low confidence in the
extended forecast due to the models varying with the timing and
strength of waves and the trough moving onto the West Coast. The
GFS is still wetter and more progressive than the ECMWF and moves
the trough through on Saturday. The forecast leans more to the
GFS with the threat of precipitation mainly over the Northern
Sacramento valley and surrounding mountains as weak waves may
brush by the north and as the trough moves inland. Temperatures
are expected to remain near to a little above normal with highs in
the mid 70s to low 80s in the Valley and 50s and 60s in the
mountains on Thursday and Friday then a little cooling over the
weekend with the trough moving inland.


&&

.Aviation...

Generally VFR conditions tonight with increasing clouds and stronger
southerly winds aft 12z as front moves through the area Monday.
Clouds and precipitation may being local MVFR conditions in the
Valley and MVFR conditions with local IFR over the Mountains after
12z Monday. ISOLD TSRA possible Monday afternoon and evening.


&&

.STO Watches/Warnings/Advisories...
None.
&&

$$









000
FXUS66 KSTO 192126
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
226 PM PDT Sun Oct 19 2014

.Synopsis...
High pressure will provide dry weather and seasonable temperatures
Sunday. Frontal system will provide cooler temperatures and
precipitation chances Monday and Monday night.

&&

.Discussion...
Ridge of high pressure will shift eastward overnight.
A weak cold front will move into the coastal range Monday morning
and spread through the interior during the day. The southern end
of the front will move through Sacramento during the afternoon
hours. The front this far south appears like it wont hold together
but may bring some showers this far south. Further north looks
like the better changes of rain. The central core of the low will
move through the interior Monday evening to keep a threat of
showers in the forecast. Once the low moves into the Great Basin
more stable air will filter in behind the system. Instability does
not look that great with this system but any thunderstorms would
likely be limited to the evening hours as the core of the low
moves inland and probably not that widespread.

Zonal flow aloft over the region for Tuesday with light northerly
winds. Cooler air will remain over the area to keep temperatures
in the lower to mid 70s for another day for the valley to the 50s
for the mountains. Some high cloudiness should be over the area
as well.

A large low will form in the Gulf of Alaska by Wednesday.
By Wednesday night some light rain may spread at times across the
far northern interior areas around Shasta county otherwise expect
dry conditions to prevail for most everyone.



.Extended Discussion (Thursday through Sunday)

A trough over the Eastern Pacific and onto the West Coast for the
later part of the week. There is still low confidence in the
extended forecast due to the models varying with the timing and
strength of waves and the trough moving onto the West Coast. The
GFS is still wetter and more progressive than the ECMWF and moves
the trough through on Saturday. The forecast leans more to the
GFS with the threat of precipitation mainly over the Northern
Sacramento valley and surrounding mountains as weak waves may
brush by the north and as the trough moves inland. Temperatures
are expected to remain near to a little above normal with highs in
the mid 70s to low 80s in the Valley and 50s and 60s in the
mountains on Thursday and Friday then a little cooling over the
weekend with the trough moving inland.


&&

.Aviation...

Generally VFR conditions tonight with increasing clouds and stronger
southerly winds aft 12z as front moves through the area Monday.
Clouds and precipitation may being local MVFR conditions in the
Valley and MVFR conditions with local IFR over the Mountains after
12z Monday. ISOLD TSRA possible Monday afternoon and evening.


&&

.STO Watches/Warnings/Advisories...
None.
&&

$$








000
FXUS66 KSTO 192126
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
226 PM PDT Sun Oct 19 2014

.Synopsis...
High pressure will provide dry weather and seasonable temperatures
Sunday. Frontal system will provide cooler temperatures and
precipitation chances Monday and Monday night.

&&

.Discussion...
Ridge of high pressure will shift eastward overnight.
A weak cold front will move into the coastal range Monday morning
and spread through the interior during the day. The southern end
of the front will move through Sacramento during the afternoon
hours. The front this far south appears like it wont hold together
but may bring some showers this far south. Further north looks
like the better changes of rain. The central core of the low will
move through the interior Monday evening to keep a threat of
showers in the forecast. Once the low moves into the Great Basin
more stable air will filter in behind the system. Instability does
not look that great with this system but any thunderstorms would
likely be limited to the evening hours as the core of the low
moves inland and probably not that widespread.

Zonal flow aloft over the region for Tuesday with light northerly
winds. Cooler air will remain over the area to keep temperatures
in the lower to mid 70s for another day for the valley to the 50s
for the mountains. Some high cloudiness should be over the area
as well.

A large low will form in the Gulf of Alaska by Wednesday.
By Wednesday night some light rain may spread at times across the
far northern interior areas around Shasta county otherwise expect
dry conditions to prevail for most everyone.



.Extended Discussion (Thursday through Sunday)

A trough over the Eastern Pacific and onto the West Coast for the
later part of the week. There is still low confidence in the
extended forecast due to the models varying with the timing and
strength of waves and the trough moving onto the West Coast. The
GFS is still wetter and more progressive than the ECMWF and moves
the trough through on Saturday. The forecast leans more to the
GFS with the threat of precipitation mainly over the Northern
Sacramento valley and surrounding mountains as weak waves may
brush by the north and as the trough moves inland. Temperatures
are expected to remain near to a little above normal with highs in
the mid 70s to low 80s in the Valley and 50s and 60s in the
mountains on Thursday and Friday then a little cooling over the
weekend with the trough moving inland.


&&

.Aviation...

Generally VFR conditions tonight with increasing clouds and stronger
southerly winds aft 12z as front moves through the area Monday.
Clouds and precipitation may being local MVFR conditions in the
Valley and MVFR conditions with local IFR over the Mountains after
12z Monday. ISOLD TSRA possible Monday afternoon and evening.


&&

.STO Watches/Warnings/Advisories...
None.
&&

$$









000
FXUS66 KSTO 191527
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
827 AM PDT Sun Oct 19 2014

.Synopsis...
High pressure will provide dry weather and seasonable temperatures
Sunday. Frontal system will provide cooler temperatures and
precipitation chances Monday and Monday night.

&&

.Discussion...
Ridge of high pressure will remain over the area today with
temperatures warming into the upper 70`s to lower 80`s for the
valley to the 50`s to mid 60`s for the mountains.

A weak cold front will move into the coastal range Monday
morning and spread through the interior during the day. the
southern end of the front will move through Sacramento during the
afternoon hours. The front this far south appears like it wont
hold together but may bring some showers this far south. Further
north looks like the better changes of rain. The central core of
the low will move through the interior Monday evening to keep a
threat of showers in the forecast. Once the low moves into the
Great Basin more stable air will filter in behind the system.
Instability does not look that great with this system but any
thunderstorms would likely be limited to the evening hours as the
core of the low moves inland and probably not that widespread.

Zonal flow aloft over the region for Tuesday with light northerly
winds. Cooler air will remain over the area to keep temperatures
in the lower to mid 70s for another day for the valley to the 50s
for the mountains. Some high cloudiness should be over the area
as well.

A large low will form in the Gulf of Alaska by Wednesday.
By Wednesday night and lasting through the remainder of the work
week the low will deepen and may bring some rain to interior
Northern California. The best chances will remain over the north
but will increase for the Sacramento area late Friday per the GFS
model which is more progressive with moving the low inland than
the other models.



.Extended Discussion (Thursday through Sunday)

For most of our CWA, the latter half of the week should be fairly
mild, dry weather with valley highs in the 70s to low 80s.
However, extended models continue to hint that the upper low in
the Gulf of Alaska could keep a slight chance of precipitation
along the Coastal range. The models diverge Friday into the
weekend as the GFS wants to track the low into the west coast and
spread the chance of precipitation across all of NorCal.
Meanwhile, the ECMWF keeps a weak ridge over NorCal. So have
blended the two solutions and kept mention of precipitation over
the Coastal range until models come into better agreement. JBB

&&

.Aviation...

VFR conditions and mainly light winds continue the next 24 hours.

&&

.STO Watches/Warnings/Advisories...
None.
&&

$$








000
FXUS66 KSTO 191527
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
827 AM PDT Sun Oct 19 2014

.Synopsis...
High pressure will provide dry weather and seasonable temperatures
Sunday. Frontal system will provide cooler temperatures and
precipitation chances Monday and Monday night.

&&

.Discussion...
Ridge of high pressure will remain over the area today with
temperatures warming into the upper 70`s to lower 80`s for the
valley to the 50`s to mid 60`s for the mountains.

A weak cold front will move into the coastal range Monday
morning and spread through the interior during the day. the
southern end of the front will move through Sacramento during the
afternoon hours. The front this far south appears like it wont
hold together but may bring some showers this far south. Further
north looks like the better changes of rain. The central core of
the low will move through the interior Monday evening to keep a
threat of showers in the forecast. Once the low moves into the
Great Basin more stable air will filter in behind the system.
Instability does not look that great with this system but any
thunderstorms would likely be limited to the evening hours as the
core of the low moves inland and probably not that widespread.

Zonal flow aloft over the region for Tuesday with light northerly
winds. Cooler air will remain over the area to keep temperatures
in the lower to mid 70s for another day for the valley to the 50s
for the mountains. Some high cloudiness should be over the area
as well.

A large low will form in the Gulf of Alaska by Wednesday.
By Wednesday night and lasting through the remainder of the work
week the low will deepen and may bring some rain to interior
Northern California. The best chances will remain over the north
but will increase for the Sacramento area late Friday per the GFS
model which is more progressive with moving the low inland than
the other models.



.Extended Discussion (Thursday through Sunday)

For most of our CWA, the latter half of the week should be fairly
mild, dry weather with valley highs in the 70s to low 80s.
However, extended models continue to hint that the upper low in
the Gulf of Alaska could keep a slight chance of precipitation
along the Coastal range. The models diverge Friday into the
weekend as the GFS wants to track the low into the west coast and
spread the chance of precipitation across all of NorCal.
Meanwhile, the ECMWF keeps a weak ridge over NorCal. So have
blended the two solutions and kept mention of precipitation over
the Coastal range until models come into better agreement. JBB

&&

.Aviation...

VFR conditions and mainly light winds continue the next 24 hours.

&&

.STO Watches/Warnings/Advisories...
None.
&&

$$









000
FXUS66 KSTO 191035
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
335 AM PDT Sun Oct 19 2014

.Synopsis...
High pressure will provide dry weather and seasonable temperatures
today. A frontal system will provide cooler temperatures and
precipitation chances Monday and Monday night.

&&

.Discussion...
One more mild day over Norcal to end the weekend...and then a
cool...showery start to the work week. An upper level trof axis
along 140W will edge Ewd today amplifying the downstream ridge over
the Intermountain West. Synoptic cooling will account for a few
degrees of cooling to the Nrn zones...while near persistence is
expected elsewhere. Meanwhile...the SE portion of the CWA (i.e.
zones 67/69) may see slight warming from yesterday.

The upper trof will move Ewd inside 130W early Mon and begin to
effect the wx over interior Norcal. The last couple of runs show a
slightly more negative tilt with the vort max moving inland Mon
nite. This may slow the progression of the trof a few hrs from
earlier runs...but precip should move across most of the CWA by late
Mon afternoon...except for the far SErn portion of the CWA...and
then over that area Mon evening. Estimated QPFs range from up to .70
inch in the Shasta Co mtns tapering to a couple hundredths in the
Nrn San Joaquin Vly to about .25 inch in the far Nrn Sac Vly. These
values could be augmented by any convection that may develop in the
NErn quad of the approaching vort max behind the surface front.

We blended the NAM/GFS instability progs and the synoptic forcing to
arrive at an area of potential thunderstorms...mainly from Butte/Wrn
Plums counties Southward...and then east of I-5...or roughly Hwy
99/70 Ewd to near the Siernev crest. Bufkit forecast soundings
indicate a strong cap on some of the profiles making the convective
forecast problematic at this time. In addition...the thunderstorm
potential appears to be limited to a short time window...roughly 3
PM til about dark...or up to 4 hrs or so. A shift in the vort max
farther N as suggested by the ECMWF may result in convection over
the Shasta Mtns and in line with the WRF. Have leaned to the NAM for
now due to the digging jet on the backside of the trof.

The trof will progress more rapidly Ewd on Mon...and by Tue morning
will be E of our CWA. Breezy winds with the front and trof will
decrease with drier and milder wx Tue/Wed. A large/deep upper low
over the GOA will maintain a flat ridge over Norcal for the
midweek period which would likely be susceptible to be overrun by
a lot of mid/high cloudiness...aka a "dirty ridge". A frontal
boundary will be strung out across the Pac NW but precip is
expected to remain NW of our CWA.    JHM



.Extended Discussion (Thursday through Sunday)

For most of our CWA, the latter half of the week should be fairly
mild, dry weather with valley highs in the 70s to low 80s.
However, extended models continue to hint that the upper low in
the Gulf of Alaska could keep a slight chance of precipitation
along the Coastal range. The models diverge Friday into the
weekend as the GFS wants to track the low into the west coast and
spread the chance of precipitation across all of NorCal.
Meanwhile, the ECMWF keeps a weak ridge over NorCal. So have
blended the two solutions and kept mention of precipitation over
the Coastal range until models come into better agreement. JBB

&&

.Aviation...

VFR conditions and mainly light winds continue the next 24 hours.

&&

.STO Watches/Warnings/Advisories...
None.
&&

$$








000
FXUS66 KSTO 191035
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
335 AM PDT Sun Oct 19 2014

.Synopsis...
High pressure will provide dry weather and seasonable temperatures
today. A frontal system will provide cooler temperatures and
precipitation chances Monday and Monday night.

&&

.Discussion...
One more mild day over Norcal to end the weekend...and then a
cool...showery start to the work week. An upper level trof axis
along 140W will edge Ewd today amplifying the downstream ridge over
the Intermountain West. Synoptic cooling will account for a few
degrees of cooling to the Nrn zones...while near persistence is
expected elsewhere. Meanwhile...the SE portion of the CWA (i.e.
zones 67/69) may see slight warming from yesterday.

The upper trof will move Ewd inside 130W early Mon and begin to
effect the wx over interior Norcal. The last couple of runs show a
slightly more negative tilt with the vort max moving inland Mon
nite. This may slow the progression of the trof a few hrs from
earlier runs...but precip should move across most of the CWA by late
Mon afternoon...except for the far SErn portion of the CWA...and
then over that area Mon evening. Estimated QPFs range from up to .70
inch in the Shasta Co mtns tapering to a couple hundredths in the
Nrn San Joaquin Vly to about .25 inch in the far Nrn Sac Vly. These
values could be augmented by any convection that may develop in the
NErn quad of the approaching vort max behind the surface front.

We blended the NAM/GFS instability progs and the synoptic forcing to
arrive at an area of potential thunderstorms...mainly from Butte/Wrn
Plums counties Southward...and then east of I-5...or roughly Hwy
99/70 Ewd to near the Siernev crest. Bufkit forecast soundings
indicate a strong cap on some of the profiles making the convective
forecast problematic at this time. In addition...the thunderstorm
potential appears to be limited to a short time window...roughly 3
PM til about dark...or up to 4 hrs or so. A shift in the vort max
farther N as suggested by the ECMWF may result in convection over
the Shasta Mtns and in line with the WRF. Have leaned to the NAM for
now due to the digging jet on the backside of the trof.

The trof will progress more rapidly Ewd on Mon...and by Tue morning
will be E of our CWA. Breezy winds with the front and trof will
decrease with drier and milder wx Tue/Wed. A large/deep upper low
over the GOA will maintain a flat ridge over Norcal for the
midweek period which would likely be susceptible to be overrun by
a lot of mid/high cloudiness...aka a "dirty ridge". A frontal
boundary will be strung out across the Pac NW but precip is
expected to remain NW of our CWA.    JHM



.Extended Discussion (Thursday through Sunday)

For most of our CWA, the latter half of the week should be fairly
mild, dry weather with valley highs in the 70s to low 80s.
However, extended models continue to hint that the upper low in
the Gulf of Alaska could keep a slight chance of precipitation
along the Coastal range. The models diverge Friday into the
weekend as the GFS wants to track the low into the west coast and
spread the chance of precipitation across all of NorCal.
Meanwhile, the ECMWF keeps a weak ridge over NorCal. So have
blended the two solutions and kept mention of precipitation over
the Coastal range until models come into better agreement. JBB

&&

.Aviation...

VFR conditions and mainly light winds continue the next 24 hours.

&&

.STO Watches/Warnings/Advisories...
None.
&&

$$







000
FXUS66 KSTO 190455
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
955 PM PDT Sat Oct 18 2014

.Synopsis...
High pressure will provide dry weather and seasonable
temperatures Sunday. Weak weather system will provide cooler
temperatures and precipitation chances Monday and Tuesday.

&&

.Discussion...
Clear skies and light winds over Norcal this evening as high pressure
has built back over the area. Current temperatures are very
similar to yesterday at this time. Current forecast is on track
and no evening update will be needed.

.Previous Discussion...
Ridge of high pressure will remain over the region through the
weekend. Temperatures on Sunday will be similar todays. Some
patches of fog may form once again in some of the mountain valleys
of Plumas County late tonight and Sunday morning.

A very weak weather system will move into the region on Monday
and Monday night. The system may bring a third of an inch or less
for the mountains and less than that for the valley. The system
will exit the region late Monday night and Tuesday morning. Breezy
conditions can be expected as the system moves through. Snow
accumulation will be minimal but the higher elevations near pass
level may be able to get a little bit.

Zonal flow aloft over the region for Tuesday with light northerly
winds. Cooler air will remain over the area to keep temperatures
in the lower to mid 70s for another day for the valley to the 50s
for the mountains. Some high cloudiness should be over the area
as well.


.Extended Discussion (Wednesday through Saturday)

For the most part, benign weather is expected through the extended
period as a weak ridge builds into Southern California. The latest
model runs have backed off on the possibility of precipitation
along the Coastal Range and Shasta County late next week,
preferring to keep it immediately along the far NW coast and
northward. Otherwise, expect temperatures to be around to slightly
above normal through the extended period under the influence of
weak high pressure.

Dang


&&

.Aviation...

VFR conditions and mainly light winds continue the next 24 hours.

Dang


&&

.STO Watches/Warnings/Advisories...
None.
&&

$$








000
FXUS66 KSTO 190455
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
955 PM PDT Sat Oct 18 2014

.Synopsis...
High pressure will provide dry weather and seasonable
temperatures Sunday. Weak weather system will provide cooler
temperatures and precipitation chances Monday and Tuesday.

&&

.Discussion...
Clear skies and light winds over Norcal this evening as high pressure
has built back over the area. Current temperatures are very
similar to yesterday at this time. Current forecast is on track
and no evening update will be needed.

.Previous Discussion...
Ridge of high pressure will remain over the region through the
weekend. Temperatures on Sunday will be similar todays. Some
patches of fog may form once again in some of the mountain valleys
of Plumas County late tonight and Sunday morning.

A very weak weather system will move into the region on Monday
and Monday night. The system may bring a third of an inch or less
for the mountains and less than that for the valley. The system
will exit the region late Monday night and Tuesday morning. Breezy
conditions can be expected as the system moves through. Snow
accumulation will be minimal but the higher elevations near pass
level may be able to get a little bit.

Zonal flow aloft over the region for Tuesday with light northerly
winds. Cooler air will remain over the area to keep temperatures
in the lower to mid 70s for another day for the valley to the 50s
for the mountains. Some high cloudiness should be over the area
as well.


.Extended Discussion (Wednesday through Saturday)

For the most part, benign weather is expected through the extended
period as a weak ridge builds into Southern California. The latest
model runs have backed off on the possibility of precipitation
along the Coastal Range and Shasta County late next week,
preferring to keep it immediately along the far NW coast and
northward. Otherwise, expect temperatures to be around to slightly
above normal through the extended period under the influence of
weak high pressure.

Dang


&&

.Aviation...

VFR conditions and mainly light winds continue the next 24 hours.

Dang


&&

.STO Watches/Warnings/Advisories...
None.
&&

$$









000
FXUS66 KSTO 190455
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
955 PM PDT Sat Oct 18 2014

.Synopsis...
High pressure will provide dry weather and seasonable
temperatures Sunday. Weak weather system will provide cooler
temperatures and precipitation chances Monday and Tuesday.

&&

.Discussion...
Clear skies and light winds over Norcal this evening as high pressure
has built back over the area. Current temperatures are very
similar to yesterday at this time. Current forecast is on track
and no evening update will be needed.

.Previous Discussion...
Ridge of high pressure will remain over the region through the
weekend. Temperatures on Sunday will be similar todays. Some
patches of fog may form once again in some of the mountain valleys
of Plumas County late tonight and Sunday morning.

A very weak weather system will move into the region on Monday
and Monday night. The system may bring a third of an inch or less
for the mountains and less than that for the valley. The system
will exit the region late Monday night and Tuesday morning. Breezy
conditions can be expected as the system moves through. Snow
accumulation will be minimal but the higher elevations near pass
level may be able to get a little bit.

Zonal flow aloft over the region for Tuesday with light northerly
winds. Cooler air will remain over the area to keep temperatures
in the lower to mid 70s for another day for the valley to the 50s
for the mountains. Some high cloudiness should be over the area
as well.


.Extended Discussion (Wednesday through Saturday)

For the most part, benign weather is expected through the extended
period as a weak ridge builds into Southern California. The latest
model runs have backed off on the possibility of precipitation
along the Coastal Range and Shasta County late next week,
preferring to keep it immediately along the far NW coast and
northward. Otherwise, expect temperatures to be around to slightly
above normal through the extended period under the influence of
weak high pressure.

Dang


&&

.Aviation...

VFR conditions and mainly light winds continue the next 24 hours.

Dang


&&

.STO Watches/Warnings/Advisories...
None.
&&

$$








000
FXUS66 KSTO 190455
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
955 PM PDT Sat Oct 18 2014

.Synopsis...
High pressure will provide dry weather and seasonable
temperatures Sunday. Weak weather system will provide cooler
temperatures and precipitation chances Monday and Tuesday.

&&

.Discussion...
Clear skies and light winds over Norcal this evening as high pressure
has built back over the area. Current temperatures are very
similar to yesterday at this time. Current forecast is on track
and no evening update will be needed.

.Previous Discussion...
Ridge of high pressure will remain over the region through the
weekend. Temperatures on Sunday will be similar todays. Some
patches of fog may form once again in some of the mountain valleys
of Plumas County late tonight and Sunday morning.

A very weak weather system will move into the region on Monday
and Monday night. The system may bring a third of an inch or less
for the mountains and less than that for the valley. The system
will exit the region late Monday night and Tuesday morning. Breezy
conditions can be expected as the system moves through. Snow
accumulation will be minimal but the higher elevations near pass
level may be able to get a little bit.

Zonal flow aloft over the region for Tuesday with light northerly
winds. Cooler air will remain over the area to keep temperatures
in the lower to mid 70s for another day for the valley to the 50s
for the mountains. Some high cloudiness should be over the area
as well.


.Extended Discussion (Wednesday through Saturday)

For the most part, benign weather is expected through the extended
period as a weak ridge builds into Southern California. The latest
model runs have backed off on the possibility of precipitation
along the Coastal Range and Shasta County late next week,
preferring to keep it immediately along the far NW coast and
northward. Otherwise, expect temperatures to be around to slightly
above normal through the extended period under the influence of
weak high pressure.

Dang


&&

.Aviation...

VFR conditions and mainly light winds continue the next 24 hours.

Dang


&&

.STO Watches/Warnings/Advisories...
None.
&&

$$









000
FXUS66 KSTO 182031
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
131 PM PDT Sat Oct 18 2014

.Synopsis...
High pressure will provide dry weather and seasonable temperatures
for the rest of the weekend. Weak weather system will provide
precipitation chances Monday and Tuesday.

&&

.Discussion...
Ridge of high pressure will remain over the region through the
weekend. Temperatures on Sunday will be similar todays. Some
patches of fog may form once again in some of the mountain valleys
of Plumas County late tonight and Sunday morning.

A very weak weather system will move into the region on Monday
and Monday night. The system may bring a third of an inch or less
for the mountains and less than that for the valley. The system
will exit the region late Monday night and Tuesday morning. Breezy
conditions can be expected as the system moves through. Snow
accumulation will be minimal but the higher elevations near pass
level may be able to get a little bit.

Zonal flow aloft over the region for Tuesday with light northerly
winds. Cooler air will remain over the area to keep temperatures
in the lower to mid 70s for another day for the valley to the 50s
for the mountains. Some high cloudiness should be over the area
as well.


.Extended Discussion (Wednesday through Saturday)

For the most part, benign weather is expected through the extended
period as a weak ridge builds into Southern California. The latest
model runs have backed off on the possibility of precipitation
along the Coastal Range and Shasta County late next week,
preferring to keep it immediately along the far NW coast and
northward. Otherwise, expect temperatures to be around to slightly
above normal through the extended period under the influence of
weak high pressure.

Dang


&&

.Aviation...

VFR conditions and mainly light winds continue the next 24 hours.

Dang


&&

.STO Watches/Warnings/Advisories...
None.
&&

$$









000
FXUS66 KSTO 182031
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
131 PM PDT Sat Oct 18 2014

.Synopsis...
High pressure will provide dry weather and seasonable temperatures
for the rest of the weekend. Weak weather system will provide
precipitation chances Monday and Tuesday.

&&

.Discussion...
Ridge of high pressure will remain over the region through the
weekend. Temperatures on Sunday will be similar todays. Some
patches of fog may form once again in some of the mountain valleys
of Plumas County late tonight and Sunday morning.

A very weak weather system will move into the region on Monday
and Monday night. The system may bring a third of an inch or less
for the mountains and less than that for the valley. The system
will exit the region late Monday night and Tuesday morning. Breezy
conditions can be expected as the system moves through. Snow
accumulation will be minimal but the higher elevations near pass
level may be able to get a little bit.

Zonal flow aloft over the region for Tuesday with light northerly
winds. Cooler air will remain over the area to keep temperatures
in the lower to mid 70s for another day for the valley to the 50s
for the mountains. Some high cloudiness should be over the area
as well.


.Extended Discussion (Wednesday through Saturday)

For the most part, benign weather is expected through the extended
period as a weak ridge builds into Southern California. The latest
model runs have backed off on the possibility of precipitation
along the Coastal Range and Shasta County late next week,
preferring to keep it immediately along the far NW coast and
northward. Otherwise, expect temperatures to be around to slightly
above normal through the extended period under the influence of
weak high pressure.

Dang


&&

.Aviation...

VFR conditions and mainly light winds continue the next 24 hours.

Dang


&&

.STO Watches/Warnings/Advisories...
None.
&&

$$








000
FXUS66 KSTO 181605
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
905 AM PDT Sat Oct 18 2014

.Synopsis...
High pressure will provide dry weather and seasonable temperatures
for the rest of the weekend. Weak weather system will provide
precipitation chances Monday and Tuesday.

&&

.Discussion...
Warmer Temperatures today under high pressure ahead of a trough
out over the pacific. Highs should warm to the upper 70s and lower
80s in the valley to the 50`s and 60`s for the mountains. Little
change in the weather is expected through the weekend under mostly
sunny skies.

A very weak weather system will move into the region on Monday
and Monday night. The system may bring a third of an inch or less
for the mountains and less than that for the valley. The system
will exit the region late Monday night and Tuesday morning. Breezy
conditions can be expected as the system moves through. Snow
accumulation will be minimal but the higher elevations near pass
level may be able to get a little bit.


.Extended Discussion (Wednesday through Saturday)

Extended models showing greater differences beyond Tuesday.
EC/GEM gradually increase heights through the remainder of the
week while the GFS keeps westerlies farther south into far
northern CA Wed/Thu. GFS also entrains remnant moisture from T.S.
Ana into the polar jet during this time and generates some light
QPF over the Coastal range and Shasta county late Wed through Sat.
EC keeps the track farther north. With ADJMRA/CONs data showing
some POPs, will hold onto a slight chance over the northwestern
mountains of Interior NorCal during that period for now.
Temperatures expected to trend up over the latter part of next,
returning to near or slightly above normal by next Friday.

&&

.Aviation...

VFR conditions continue for the next 24 hours. Light northerly surface
winds today and TAF sites should be less than 8 kts.  JBB

&&

.STO Watches/Warnings/Advisories...
None.
&&

$$








000
FXUS66 KSTO 181605
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
905 AM PDT Sat Oct 18 2014

.Synopsis...
High pressure will provide dry weather and seasonable temperatures
for the rest of the weekend. Weak weather system will provide
precipitation chances Monday and Tuesday.

&&

.Discussion...
Warmer Temperatures today under high pressure ahead of a trough
out over the pacific. Highs should warm to the upper 70s and lower
80s in the valley to the 50`s and 60`s for the mountains. Little
change in the weather is expected through the weekend under mostly
sunny skies.

A very weak weather system will move into the region on Monday
and Monday night. The system may bring a third of an inch or less
for the mountains and less than that for the valley. The system
will exit the region late Monday night and Tuesday morning. Breezy
conditions can be expected as the system moves through. Snow
accumulation will be minimal but the higher elevations near pass
level may be able to get a little bit.


.Extended Discussion (Wednesday through Saturday)

Extended models showing greater differences beyond Tuesday.
EC/GEM gradually increase heights through the remainder of the
week while the GFS keeps westerlies farther south into far
northern CA Wed/Thu. GFS also entrains remnant moisture from T.S.
Ana into the polar jet during this time and generates some light
QPF over the Coastal range and Shasta county late Wed through Sat.
EC keeps the track farther north. With ADJMRA/CONs data showing
some POPs, will hold onto a slight chance over the northwestern
mountains of Interior NorCal during that period for now.
Temperatures expected to trend up over the latter part of next,
returning to near or slightly above normal by next Friday.

&&

.Aviation...

VFR conditions continue for the next 24 hours. Light northerly surface
winds today and TAF sites should be less than 8 kts.  JBB

&&

.STO Watches/Warnings/Advisories...
None.
&&

$$









000
FXUS66 KSTO 181605
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
905 AM PDT Sat Oct 18 2014

.Synopsis...
High pressure will provide dry weather and seasonable temperatures
for the rest of the weekend. Weak weather system will provide
precipitation chances Monday and Tuesday.

&&

.Discussion...
Warmer Temperatures today under high pressure ahead of a trough
out over the pacific. Highs should warm to the upper 70s and lower
80s in the valley to the 50`s and 60`s for the mountains. Little
change in the weather is expected through the weekend under mostly
sunny skies.

A very weak weather system will move into the region on Monday
and Monday night. The system may bring a third of an inch or less
for the mountains and less than that for the valley. The system
will exit the region late Monday night and Tuesday morning. Breezy
conditions can be expected as the system moves through. Snow
accumulation will be minimal but the higher elevations near pass
level may be able to get a little bit.


.Extended Discussion (Wednesday through Saturday)

Extended models showing greater differences beyond Tuesday.
EC/GEM gradually increase heights through the remainder of the
week while the GFS keeps westerlies farther south into far
northern CA Wed/Thu. GFS also entrains remnant moisture from T.S.
Ana into the polar jet during this time and generates some light
QPF over the Coastal range and Shasta county late Wed through Sat.
EC keeps the track farther north. With ADJMRA/CONs data showing
some POPs, will hold onto a slight chance over the northwestern
mountains of Interior NorCal during that period for now.
Temperatures expected to trend up over the latter part of next,
returning to near or slightly above normal by next Friday.

&&

.Aviation...

VFR conditions continue for the next 24 hours. Light northerly surface
winds today and TAF sites should be less than 8 kts.  JBB

&&

.STO Watches/Warnings/Advisories...
None.
&&

$$








000
FXUS66 KSTO 181058
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
358 AM PDT Sat Oct 18 2014

.Synopsis...
High pressure will provide dry weather and seasonable temperatures
for the rest of the weekend. Weak weather systems will provide
precipitation chances Monday and Tuesday.

&&

.Discussion...
Weakening trough along the coast will be replaced by ridging for
the rest of the weekend. This will provide near normal temperatures
and mostly sunny skies.

Upper trough will dig south along the coast Monday and swing east
through Norcal Monday evening. This will bring a return of
showers and cause cooler temperatures. Rainfall amounts look to
light with the system with current forecasted amounts generally less
than 0.25 inches. Temperatures will cool to 4-8 degrees below
normal.

Trough will move east into the great basin on Tuesday with a
somewhat moist westerly flow continuing behind the system over
Norcal. This will keep slight shower chances going for the coastal
range and Shasta county. Temperature as will remain slightly below
normal.

.Extended Discussion (Wednesday through Saturday)

Extended models showing significant differences. EC/GEM gradually
increase heights through the remainder of the week while the GFS
keeps westerlies farther south into far northern CA Wed/Thu. GFS
also entrains remnant moisture from T.S. Ana into the polar jet
during this time and generates some light QPF over the Coastal
range and Shasta county late Wed through Sat. EC keeps the track
farther north. With ADJMRA/CONs data showing some POPs, will hold
onto a slight chance over the northwestern mountains of Interior
NorCal during that period for now. Temperatures expected to trend
up over the latter part of next, returning to near or slightly
above normal by next Friday.

&&

.Aviation...

VFR conditions continue for the next 24 hours. Light northerly surface
winds today and TAF sites should be less than 8 kts.  JBB

&&

.STO Watches/Warnings/Advisories...
None.
&&

$$








000
FXUS66 KSTO 181058
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
358 AM PDT Sat Oct 18 2014

.Synopsis...
High pressure will provide dry weather and seasonable temperatures
for the rest of the weekend. Weak weather systems will provide
precipitation chances Monday and Tuesday.

&&

.Discussion...
Weakening trough along the coast will be replaced by ridging for
the rest of the weekend. This will provide near normal temperatures
and mostly sunny skies.

Upper trough will dig south along the coast Monday and swing east
through Norcal Monday evening. This will bring a return of
showers and cause cooler temperatures. Rainfall amounts look to
light with the system with current forecasted amounts generally less
than 0.25 inches. Temperatures will cool to 4-8 degrees below
normal.

Trough will move east into the great basin on Tuesday with a
somewhat moist westerly flow continuing behind the system over
Norcal. This will keep slight shower chances going for the coastal
range and Shasta county. Temperature as will remain slightly below
normal.

.Extended Discussion (Wednesday through Saturday)

Extended models showing significant differences. EC/GEM gradually
increase heights through the remainder of the week while the GFS
keeps westerlies farther south into far northern CA Wed/Thu. GFS
also entrains remnant moisture from T.S. Ana into the polar jet
during this time and generates some light QPF over the Coastal
range and Shasta county late Wed through Sat. EC keeps the track
farther north. With ADJMRA/CONs data showing some POPs, will hold
onto a slight chance over the northwestern mountains of Interior
NorCal during that period for now. Temperatures expected to trend
up over the latter part of next, returning to near or slightly
above normal by next Friday.

&&

.Aviation...

VFR conditions continue for the next 24 hours. Light northerly surface
winds today and TAF sites should be less than 8 kts.  JBB

&&

.STO Watches/Warnings/Advisories...
None.
&&

$$








000
FXUS66 KSTO 180527
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
1027 PM PDT Fri Oct 17 2014

.Synopsis...
Weak weather systems will provide precipitation chances again
Monday and Tuesday. Heavy precipitation is not expected.
Seasonable temperatures through the weekend.

&&

.Discussion...Trough weakening rapidly this evening as it loses
upper level support. Have updated to remove rain chances all areas
except coastal range and Shasta county. Also reduced cloud cover
most areas to align with latest satellite imagery.
Otherwise...forecast is on track.

.Previous Discussion (Tonight through Monday)... Mostly cloudy
tonight over NorCal as the Upper level moves over the area. This
system has continued to weaken as it moved onshore, and
precipitation has mainly stayed west of the Coastal Range crest.
Areas of rain are possible mainly over the Coastal Range this
evening into Sat morning as the trough and weak cyclonic
circulation sink southeastward along the CA coast. Later Sat and
into Sun, ridging returns to NorCal with clearing skies and milder
temps.

A slightly deeper Pacific trough is forecast to impact NorCal on
Mon into Tue with the bulk of the precip remaining N of I-80. Even
so, models still only show up to 0.30 inches in the Shasta
mountains and Sierra. While the northwest coast should get a
decent amount of rain, interior NorCal will apparently be short
changed due to shallow moisture. As long as the persistent upper
High over the Intermountain West and Great Plains remains, the
parent Gulf of Alaska Low isn`t progressing east. The spawned
short waves from the parent Low weaken as they move inland, thus
limiting precipitation amounts.     JClapp


.Extended Discussion (Tuesday through Friday)

Model differences in timing have decreased with Pacific frontal
system progged to impact Interior NorCal Monday. Precip forecast to
spread into the Coastal Range Monday morning, then expand east
across the Central Valley into the Sierra, during the afternoon
into night. Storm total QPF looking fairly light with the heaviest
precip, locally up to around half an inch, expected in portions of
the eastern foothills/mountains. Snow levels overnight Monday look
to be just above 7000 feet in the Shasta mountains to near 8000
feet along the I-80 corridor. Light snow accumulations possible
over the highest terrain. Secondary weak upper trough moves
through Tuesday morning keeping a slight chance of showers, mainly
over the mountains, then increasing subsidence into Tue afternoon.
High temperatures Mon/Tue expected to be around 5 to 10 degrees
below normal.

Extended models showing greater differences beyond Tuesday. EC/GEM
gradually increase heights through the remainder of the week while
the GFS keeps westerlies farther south into far northern CA
Wed/Thu. GFS also entrains remnant moisture from T.S. Ana into the
polar jet during this time and generates some light QPF over the
Coastal range and Shasta county late Wed through Thu. EC keeps the
track farther north. With ADJMRA/CONs data showing some POPs, will
hold onto a slight chance over the northwestern mountains of
Interior NorCal during that period for now. Temperatures expected
to trend up over the latter part of next, returning to near or
slightly above normal by next Friday.
PCH

&&

.Aviation...

Wkng Pac cdfnt movg onshr attm flwd by assocd upr trof tngt into
Sat mrng. Mnly VFR conds ovr Intr NorCal exc lcl MVFR/IFR poss
omtns ovngt. SWly flow alf vrg to Nly Sat mrng. Lcl SWly sfc wnd
gsts to 30 kts poss ovr hyr mtn trrn til 06z Sat.


&&

.STO Watches/Warnings/Advisories...
None.
&&

$$








000
FXUS66 KSTO 172219
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
319 PM PDT Fri Oct 17 2014

.Synopsis...
Weak weather systems will continue precipitation chances tonight and
Saturday morning and again Monday and Tuesday. Heavy precipitation
is not expected. Seasonable temperatures through the weekend.

&&

.Short Term Discussion (Tonight through Monday)...
Mostly cloudy tonight over NorCal as the Upper level moves over
the area. This system has continued to weaken as it moved onshore,
and precipitation has mainly stayed west of the Coastal Range
crest. Areas of rain are possible mainly over the Coastal Range
this evening into Sat morning as the trough and weak cyclonic
circulation sink southeastward along the CA coast. Later Sat and
into Sun, ridging returns to NorCal with clearing skies and milder
temps.

A slightly deeper Pacific trough is forecast to impact NorCal on
Mon into Tue with the bulk of the precip remaining N of I-80. Even
so, models still only show up to 0.30 inches in the Shasta
mountains and Sierra. While the northwest coast should get a
decent amount of rain, interior NorCal will apparently be short
changed due to shallow moisture. As long as the persistent upper
High over the Intermountain West and Great Plains remains, the
parent Gulf of Alaska Low isn`t progressing east. The spawned
short waves from the parent Low weaken as they move inland, thus
limiting precipitation amounts.     JClapp


.Extended Discussion (Tuesday through Friday)
Model differences in timing have decreased with Pacific frontal
system progged to impact Interior NorCal Monday. Precip forecast
to spread into the Coastal Range Monday morning, then expand east
across the Central Valley into the Sierra, during the afternoon
into night. Snow levels overnight Monday look to be just above
7000 feet in the Shasta mountains to near 8000 feet along the I-80
corridor. Light snow accumulations possible over the highest
terrain. Secondary weak upper trough moves through Tuesday morning
keeping a slight chance of showers, mainly over the mountains,
then increasing subsidence into Tue afternoon. High temperatures
Mon/Tue expected to be around 5 to 10 degrees below normal.

Extended models showing greater differences beyond Tuesday. EC/GEM
gradually increase heights through the remainder of the week while
the GFS keeps westerlies farther south into far northern CA
Wed/Thu. GFS also entrains remnant moisture from T.S. Ana into the
polar jet during this time and generates some light QPF over the
Coastal range and Shasta county late Wed through Thu. EC keeps the
track farther north. With ADJMRA/CONs data showing some POPs, will
hold onto a slight chance over the northwestern mountains of
Interior NorCal during that period for now. Temperatures expected
to trend up over the latter part of next week, returning to near or
slightly above normal by next Friday.    PCH

&&

.Aviation...
Wkng Pac cdfnt movg onshr attm flwd by assocd upr trof tngt into
Sat mrng. Mnly VFR conds ovr Intr NorCal exc lcl MVFR/IFR poss
omtns ovngt. SWly flow alf vrg to Nly Sat mrng. Lcl SWly sfc wnd
gsts to 30 kts poss ovr hyr mtn trrn til 06z Sat.


&&

.STO Watches/Warnings/Advisories...
None.
&&

$$








000
FXUS66 KSTO 172219
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
319 PM PDT Fri Oct 17 2014

.Synopsis...
Weak weather systems will continue precipitation chances tonight and
Saturday morning and again Monday and Tuesday. Heavy precipitation
is not expected. Seasonable temperatures through the weekend.

&&

.Short Term Discussion (Tonight through Monday)...
Mostly cloudy tonight over NorCal as the Upper level moves over
the area. This system has continued to weaken as it moved onshore,
and precipitation has mainly stayed west of the Coastal Range
crest. Areas of rain are possible mainly over the Coastal Range
this evening into Sat morning as the trough and weak cyclonic
circulation sink southeastward along the CA coast. Later Sat and
into Sun, ridging returns to NorCal with clearing skies and milder
temps.

A slightly deeper Pacific trough is forecast to impact NorCal on
Mon into Tue with the bulk of the precip remaining N of I-80. Even
so, models still only show up to 0.30 inches in the Shasta
mountains and Sierra. While the northwest coast should get a
decent amount of rain, interior NorCal will apparently be short
changed due to shallow moisture. As long as the persistent upper
High over the Intermountain West and Great Plains remains, the
parent Gulf of Alaska Low isn`t progressing east. The spawned
short waves from the parent Low weaken as they move inland, thus
limiting precipitation amounts.     JClapp


.Extended Discussion (Tuesday through Friday)
Model differences in timing have decreased with Pacific frontal
system progged to impact Interior NorCal Monday. Precip forecast
to spread into the Coastal Range Monday morning, then expand east
across the Central Valley into the Sierra, during the afternoon
into night. Snow levels overnight Monday look to be just above
7000 feet in the Shasta mountains to near 8000 feet along the I-80
corridor. Light snow accumulations possible over the highest
terrain. Secondary weak upper trough moves through Tuesday morning
keeping a slight chance of showers, mainly over the mountains,
then increasing subsidence into Tue afternoon. High temperatures
Mon/Tue expected to be around 5 to 10 degrees below normal.

Extended models showing greater differences beyond Tuesday. EC/GEM
gradually increase heights through the remainder of the week while
the GFS keeps westerlies farther south into far northern CA
Wed/Thu. GFS also entrains remnant moisture from T.S. Ana into the
polar jet during this time and generates some light QPF over the
Coastal range and Shasta county late Wed through Thu. EC keeps the
track farther north. With ADJMRA/CONs data showing some POPs, will
hold onto a slight chance over the northwestern mountains of
Interior NorCal during that period for now. Temperatures expected
to trend up over the latter part of next week, returning to near or
slightly above normal by next Friday.    PCH

&&

.Aviation...
Wkng Pac cdfnt movg onshr attm flwd by assocd upr trof tngt into
Sat mrng. Mnly VFR conds ovr Intr NorCal exc lcl MVFR/IFR poss
omtns ovngt. SWly flow alf vrg to Nly Sat mrng. Lcl SWly sfc wnd
gsts to 30 kts poss ovr hyr mtn trrn til 06z Sat.


&&

.STO Watches/Warnings/Advisories...
None.
&&

$$









000
FXUS66 KSTO 172219
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
319 PM PDT Fri Oct 17 2014

.Synopsis...
Weak weather systems will continue precipitation chances tonight and
Saturday morning and again Monday and Tuesday. Heavy precipitation
is not expected. Seasonable temperatures through the weekend.

&&

.Short Term Discussion (Tonight through Monday)...
Mostly cloudy tonight over NorCal as the Upper level moves over
the area. This system has continued to weaken as it moved onshore,
and precipitation has mainly stayed west of the Coastal Range
crest. Areas of rain are possible mainly over the Coastal Range
this evening into Sat morning as the trough and weak cyclonic
circulation sink southeastward along the CA coast. Later Sat and
into Sun, ridging returns to NorCal with clearing skies and milder
temps.

A slightly deeper Pacific trough is forecast to impact NorCal on
Mon into Tue with the bulk of the precip remaining N of I-80. Even
so, models still only show up to 0.30 inches in the Shasta
mountains and Sierra. While the northwest coast should get a
decent amount of rain, interior NorCal will apparently be short
changed due to shallow moisture. As long as the persistent upper
High over the Intermountain West and Great Plains remains, the
parent Gulf of Alaska Low isn`t progressing east. The spawned
short waves from the parent Low weaken as they move inland, thus
limiting precipitation amounts.     JClapp


.Extended Discussion (Tuesday through Friday)
Model differences in timing have decreased with Pacific frontal
system progged to impact Interior NorCal Monday. Precip forecast
to spread into the Coastal Range Monday morning, then expand east
across the Central Valley into the Sierra, during the afternoon
into night. Snow levels overnight Monday look to be just above
7000 feet in the Shasta mountains to near 8000 feet along the I-80
corridor. Light snow accumulations possible over the highest
terrain. Secondary weak upper trough moves through Tuesday morning
keeping a slight chance of showers, mainly over the mountains,
then increasing subsidence into Tue afternoon. High temperatures
Mon/Tue expected to be around 5 to 10 degrees below normal.

Extended models showing greater differences beyond Tuesday. EC/GEM
gradually increase heights through the remainder of the week while
the GFS keeps westerlies farther south into far northern CA
Wed/Thu. GFS also entrains remnant moisture from T.S. Ana into the
polar jet during this time and generates some light QPF over the
Coastal range and Shasta county late Wed through Thu. EC keeps the
track farther north. With ADJMRA/CONs data showing some POPs, will
hold onto a slight chance over the northwestern mountains of
Interior NorCal during that period for now. Temperatures expected
to trend up over the latter part of next week, returning to near or
slightly above normal by next Friday.    PCH

&&

.Aviation...
Wkng Pac cdfnt movg onshr attm flwd by assocd upr trof tngt into
Sat mrng. Mnly VFR conds ovr Intr NorCal exc lcl MVFR/IFR poss
omtns ovngt. SWly flow alf vrg to Nly Sat mrng. Lcl SWly sfc wnd
gsts to 30 kts poss ovr hyr mtn trrn til 06z Sat.


&&

.STO Watches/Warnings/Advisories...
None.
&&

$$








000
FXUS66 KSTO 171659
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
959 AM PDT Fri Oct 17 2014

.Synopsis...
Weak weather systems will bring precipitation chances today and
Saturday morning and again Monday and Tuesday. Heavy precipitation
is not expected. Seasonable temperatures through the weekend.

&&

.Discussion...
Clouds will increase/thicken over NorCal today in advance of a
longer wave Ern Pacific trof near the coast at press time. Upper
level support (winds) are forecast to weaken as the trough moves
inland. Thus, this modest looking wx system will precipitate
mainly over the Coastal Range with very little elsewhere.

Isolated to scattered showers are possible mainly W of the
Coastal Range this evening into Sat morning as the trough and
weak cyclonic circulation sink SEwd along the CA coast. Later Sat
and into Sun...ridging returns to NorCal with clearing skies and
milder temps.

A deeper Pacific trof is forecast to impact NorCal on Mon with the
bulk of the precip remaining N of I-80. This deeper system should
bring some rain to most of our CWA...with the emphasis on "some".
While the coast should get a decent amount of rain...interior NorCal
will apparently be short changed due to shallow moisture...mainly
below 600-500 mbs...a short period of favorable dynamics with the
available moisture Mon afternoon/evening when the bulk of the
precip is expected to fall in our CWA...and by mostly parallel
southerly flow for the Siernev instead of orthogonal leading to a
short duration of orographic enhancement. Despite these short
comings...Mon`s system should be wetter than today`s. Estimated
QPFs range from up to .50 inch in the mtns tapering to .10 to .25
inch in the valley.    JHM/JClapp


.Extended Discussion (Tuesday through Friday)

Extended models in good agreement that the front moving into
NorCal on Monday will continue into Tuesday morning. Precipitation
is expected to dissipate Tuesday afternoon with dry conditions by
Tuesday night. Daytime highs on Tuesday will be around 3-8 degrees
below normal with valley max temps in the low 70s.

Generally dry weather with a warming trend through Friday.
However, a large, fairly stationary low in the Gulf of Alaska may
push a weak wave just inland enough to bring a slight chance of
light showers over the coastal range into Shasta county on
Thursday morning. Impacts should be minimal.

Highs return to slightly above normal by Thursday with lower 80s
in the Central Valley and mainly 60s to 70s for the mountains and
foothills. JBB/PCH


&&

.Aviation...
Another Pacific front is approaching NorCal. High clouds will be
streaming over the region while VFR conditions are dominant. Local
MVFR conditions possible over the Coastal range during the frontal
passage. Southwesterly flow aloft with gusts up to 30 kts over
mountain ridges. Surface winds will be southerly between 5-12 kts.
JBB


&&

.STO Watches/Warnings/Advisories...
None.
&&

$$








000
FXUS66 KSTO 171659
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
959 AM PDT Fri Oct 17 2014

.Synopsis...
Weak weather systems will bring precipitation chances today and
Saturday morning and again Monday and Tuesday. Heavy precipitation
is not expected. Seasonable temperatures through the weekend.

&&

.Discussion...
Clouds will increase/thicken over NorCal today in advance of a
longer wave Ern Pacific trof near the coast at press time. Upper
level support (winds) are forecast to weaken as the trough moves
inland. Thus, this modest looking wx system will precipitate
mainly over the Coastal Range with very little elsewhere.

Isolated to scattered showers are possible mainly W of the
Coastal Range this evening into Sat morning as the trough and
weak cyclonic circulation sink SEwd along the CA coast. Later Sat
and into Sun...ridging returns to NorCal with clearing skies and
milder temps.

A deeper Pacific trof is forecast to impact NorCal on Mon with the
bulk of the precip remaining N of I-80. This deeper system should
bring some rain to most of our CWA...with the emphasis on "some".
While the coast should get a decent amount of rain...interior NorCal
will apparently be short changed due to shallow moisture...mainly
below 600-500 mbs...a short period of favorable dynamics with the
available moisture Mon afternoon/evening when the bulk of the
precip is expected to fall in our CWA...and by mostly parallel
southerly flow for the Siernev instead of orthogonal leading to a
short duration of orographic enhancement. Despite these short
comings...Mon`s system should be wetter than today`s. Estimated
QPFs range from up to .50 inch in the mtns tapering to .10 to .25
inch in the valley.    JHM/JClapp


.Extended Discussion (Tuesday through Friday)

Extended models in good agreement that the front moving into
NorCal on Monday will continue into Tuesday morning. Precipitation
is expected to dissipate Tuesday afternoon with dry conditions by
Tuesday night. Daytime highs on Tuesday will be around 3-8 degrees
below normal with valley max temps in the low 70s.

Generally dry weather with a warming trend through Friday.
However, a large, fairly stationary low in the Gulf of Alaska may
push a weak wave just inland enough to bring a slight chance of
light showers over the coastal range into Shasta county on
Thursday morning. Impacts should be minimal.

Highs return to slightly above normal by Thursday with lower 80s
in the Central Valley and mainly 60s to 70s for the mountains and
foothills. JBB/PCH


&&

.Aviation...
Another Pacific front is approaching NorCal. High clouds will be
streaming over the region while VFR conditions are dominant. Local
MVFR conditions possible over the Coastal range during the frontal
passage. Southwesterly flow aloft with gusts up to 30 kts over
mountain ridges. Surface winds will be southerly between 5-12 kts.
JBB


&&

.STO Watches/Warnings/Advisories...
None.
&&

$$









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