Home > Products > Valid Products > AFD

000
FXUS66 KSTO 302206
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
306 PM PDT Thu Oct 30 2014

.Synopsis...
A cold front will impact interior NorCal Friday into Saturday.
The front will bring rain, mountain snow, cooler temperatures, and
a slight chance of thunderstorms. Snow levels will lower to around
5000-6000 ft by early Saturday morning. Showers are expected
behind the front on Saturday then end Sunday. Drier and milder
weather early next week.

&&

.Short Term Discussion (Tonight through Sunday)...
Have made some changes to this afternoon`s forecast. Latest models
are showing higher snow levels, slower timing, and that the
greater snow impacts will be farther south than anticipated. We have
cancelled the Winter Storm Watch for Western Plumas County and
Lassen Park. Parts of Lassen Park (especially the peak of Mt.
Lassen) will still see some snow, but the coverage is not very
widespread. The Western Sierra slopes south of Plumas county will
have greater snow impacts so we upgraded the Winter Storm Watch
for that region to a Warning. The other changes to this Warning are
that we raised the elevation to above 6000 ft (the Watch was
at 5000 ft) and adjusted the timing from 5 pm Friday through 2 pm
Saturday. Motorists in the Sierra need to be prepared for winter driving.

The big focus is how will the weather impact Halloween. First off,
the forecast continues to call for a wet day across NorCal with a
slight chance of thunderstorms. The brunt of precipitation in the valley is
still on track to arrive before 5 pm, but light rain will continue
during typical Trick-or-Treating hours. If you are at higher
elevations, expect rain to turn to snow above 6000 ft sometime
after 5 pm. Bottom line: have an umbrella, be careful driving as
roads will be slick, and stay sheltered if you hear thunder or see
lightning nearby.

Daytime highs on Halloween will be notably cooler than the past
couple of days. Valley highs will be in the low to upper 60s while
mountain regions peak in the 50s. After 5 pm, temperatures during
Trick-or-Treat hours will be: Valley - upper 50s to low 60s,
Mountains - 40s to 50s.

Showers are likely to continue on Saturday but are expected to
diminish by late morning/early afternoon. Saturday highs under
the cooler airmass are forecast to be about 10 degrees below
normal. Lingering light showers along the Sierra could continue
into Sunday morning, but rebuilding high pressure will end precipitation
by Sunday afternoon. Sunday highs will start to move upward again
as a warmer and drier trend settles in for the first half of next week.
JBB
&&

.Extended Discussion (Monday through Thursday)
High pressure ridging along the west coast will be the dominant
weather feature through the extended period. Daytime highs will
slowly be climbing Monday through Thursday reaching to around
normal. Extended models move a weak system over the north end of
the ridge and into the Pacific Northwest around Tuesday but keep
any precipitation north of the forecast area. Therefore...extended
period remains dry for now. Extended models hinting at a return to
a wetter pattern towards the end of next week but have been rather
inconsistent both run to run and model to model so confidence in
this change not especially high at this time.

&&

.Aviation...
VFR conditions expected to continue the next 18 hours. A frontal
system will begin to approach the area tonight, with light showers
spreading across the Coastal Range after midnight tonight and into
Valley toward sunrise and after. Southerly winds dominating Fri
ahead of front. SW mountain wind gusts up to 30 kt will be
possible.

JClapp


&&

.STO Watches/Warnings/Advisories...
Winter Storm Warning from 5 pm Friday to 2 pm PDT Saturday above
6000 feet in the west slope Northern Sierra Nevada.

&&

$$









000
FXUS66 KSTO 302206
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
306 PM PDT Thu Oct 30 2014

.Synopsis...
A cold front will impact interior NorCal Friday into Saturday.
The front will bring rain, mountain snow, cooler temperatures, and
a slight chance of thunderstorms. Snow levels will lower to around
5000-6000 ft by early Saturday morning. Showers are expected
behind the front on Saturday then end Sunday. Drier and milder
weather early next week.

&&

.Short Term Discussion (Tonight through Sunday)...
Have made some changes to this afternoon`s forecast. Latest models
are showing higher snow levels, slower timing, and that the
greater snow impacts will be farther south than anticipated. We have
cancelled the Winter Storm Watch for Western Plumas County and
Lassen Park. Parts of Lassen Park (especially the peak of Mt.
Lassen) will still see some snow, but the coverage is not very
widespread. The Western Sierra slopes south of Plumas county will
have greater snow impacts so we upgraded the Winter Storm Watch
for that region to a Warning. The other changes to this Warning are
that we raised the elevation to above 6000 ft (the Watch was
at 5000 ft) and adjusted the timing from 5 pm Friday through 2 pm
Saturday. Motorists in the Sierra need to be prepared for winter driving.

The big focus is how will the weather impact Halloween. First off,
the forecast continues to call for a wet day across NorCal with a
slight chance of thunderstorms. The brunt of precipitation in the valley is
still on track to arrive before 5 pm, but light rain will continue
during typical Trick-or-Treating hours. If you are at higher
elevations, expect rain to turn to snow above 6000 ft sometime
after 5 pm. Bottom line: have an umbrella, be careful driving as
roads will be slick, and stay sheltered if you hear thunder or see
lightning nearby.

Daytime highs on Halloween will be notably cooler than the past
couple of days. Valley highs will be in the low to upper 60s while
mountain regions peak in the 50s. After 5 pm, temperatures during
Trick-or-Treat hours will be: Valley - upper 50s to low 60s,
Mountains - 40s to 50s.

Showers are likely to continue on Saturday but are expected to
diminish by late morning/early afternoon. Saturday highs under
the cooler airmass are forecast to be about 10 degrees below
normal. Lingering light showers along the Sierra could continue
into Sunday morning, but rebuilding high pressure will end precipitation
by Sunday afternoon. Sunday highs will start to move upward again
as a warmer and drier trend settles in for the first half of next week.
JBB
&&

.Extended Discussion (Monday through Thursday)
High pressure ridging along the west coast will be the dominant
weather feature through the extended period. Daytime highs will
slowly be climbing Monday through Thursday reaching to around
normal. Extended models move a weak system over the north end of
the ridge and into the Pacific Northwest around Tuesday but keep
any precipitation north of the forecast area. Therefore...extended
period remains dry for now. Extended models hinting at a return to
a wetter pattern towards the end of next week but have been rather
inconsistent both run to run and model to model so confidence in
this change not especially high at this time.

&&

.Aviation...
VFR conditions expected to continue the next 18 hours. A frontal
system will begin to approach the area tonight, with light showers
spreading across the Coastal Range after midnight tonight and into
Valley toward sunrise and after. Southerly winds dominating Fri
ahead of front. SW mountain wind gusts up to 30 kt will be
possible.

JClapp


&&

.STO Watches/Warnings/Advisories...
Winter Storm Warning from 5 pm Friday to 2 pm PDT Saturday above
6000 feet in the west slope Northern Sierra Nevada.

&&

$$









000
FXUS66 KSTO 301724
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
1024 AM PDT Thu Oct 30 2014

.Synopsis...
Mild weather today. A cold front will impact interior northern
California by early Friday morning as it moves across the Coastal Range.
The front will bring rain and mountain snow, cooler temperatures,
and a slight chance of thunderstorms. Snow levels will lower to around
5000-6000 ft by Saturday morning. Showers are expected behind the
front on Saturday then end Sunday with drier and milder weather
early next week.

&&

.Discussion...

Storm is trending slower and it looks like the higher impacts will
be farther south (south of Plumas County). We are looking at adjusting
timing of this storm and the snow levels are also trending higher
(closer to 6000 ft). The good news is that the snow impacts are more
likely to occur later on Friday night which is better news for
Trick-or-Treaters at higher elevations. However, moderate to
heavy rain along with the slight chance of thunderstorms will
continue to be a factor for Halloween activities. Our changes to the
Winter Storm Watch will be done by this afternoon...so stay tuned.
JBB

.Previous Discussion...
Daytime highs will cool slightly from Wednesday but
still remain a little above normal for this time of year. The
Pacific cold front is forecast to move into northern California on
Friday bringing rain and mountain snow and enough instability for
a slight threat of thunderstorms especially over the western half
of the CWA. Model timing of this frontal system is becoming more
consistent amongst the models with current timing putting the
frontal boundary over the central valley around 00z Friday. Not
real good timing for trick or treaters who will be under the rainy
effects of the back edge of the front early Friday evening. By 12z
Saturday morning the main frontal band should be over the Sierra.
Colder air filtering in behind this front will bring a rapid drop
in snow levels. By 12z Saturday...snow levels over the CWA should
range from 4000 to 5000 feet. Showers are likely on Saturday under
upper level cyclonic flow. Saturday afternoon highs under the
cooler airmass are forecast to come in around 10 degrees below
normal. Mid range models move the upper trough axis into the Great
Basin by 12z Sunday morning. Rebuilding high pressure will bring
an end to any precipitation threat by Sunday afternoon along with
the beginning of a warming trend.

&&

.Extended Discussion (Monday through Thursday)

High pressure ridging along the west coast will be the dominant
weather feature through the extended period. Daytime highs will
slowly be climbing Monday through Thursday reaching to around
normal. Extended models move a weak system over the north end of
the ridge and into the Pacific Northwest around Tuesday but keep
any precipitation north of the forecast area. Therefore...extended
period remains dry for now. Extended models hinting at a return to
a wetter pattern towards the end of next week but have been rather
inconsistent both run to run and model to model so confidence in
this change not especially high at this time.

&&

.Aviation...

VFR conditions expected to continue the next 24 hours. A frontal
system will begin to approach the area tonight, with light showers
spreading across the Coastal Range after midnight tonight. Light
winds across the Valley this morning will become southerly up to
10 kt. Along the mountains, SW wind gusts up to 30 kt will be
possible this afternoon.

Dang


&&

.STO Watches/Warnings/Advisories...
winter storm watch from friday morning through saturday
afternoon above 5000 feet in the west slope northern sierra
nevada...western plumas county/lassen park.

&&

$$









000
FXUS66 KSTO 301036
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
336 AM PDT Thu Oct 30 2014

.Synopsis...
Mild weather for Today under upper level high pressure. A cold
front will impact interior northern California beginning tonight
then moving through norcal on Friday. The front will bring rain
and mountain snow along with cooler temperatures, and a slight
chance of thunderstorms. Showers are expected behind the front on
Saturday. Snow levels will lower to around 4500 ft Saturday
morning. Showers ending early Sunday with drier and milder weather
early next week.

&&

.Discussion...
Forecast area under mainly fair skies this morning under high
pressure ridge currently over the western U.S. A Pacific frontal
system will be pushing this ridge eastward over the next few days
bringing a significant change in the weather pattern. High
cloudiness being pulled northward into the area today ahead of an
offshore cold front will bring the first signs of weather pattern
change. Daytime highs will cool slightly from Wednesday but still
remain a little above normal for this time of year. The Pacific
cold front is forecast to move into northern California on Friday
bringing rain and mountain snow and enough instability for a
slight threat of thunderstorms especially over the western half of
the CWA. Model timing of this frontal system is becoming more
consistent amongst the models with current timing putting the
frontal boundary over the central valley around 00z Friday. Not
real good timing for trick or treaters who will be under the rainy
effects of the back edge of the front early Friday evening. By 12z
Saturday morning the main frontal band should be over the Sierra.
Colder air filtering in behind this front will bring a rapid drop
in snow levels. By 12z Saturday...snow levels over the CWA should
range from 4000 to 5000 feet. Showers are likely on Saturday under
upper level cyclonic flow. Saturday afternoon highs under the
cooler airmass are forecast to come in around 10 degrees below
normal. Mid range models move the upper trough axis into the Great
Basin by 12z Sunday morning. Rebuilding high pressure will bring
an end to any precipitation threat by Sunday afternoon along with
the beginning of a warming trend.

&&

.Extended Discussion (Monday through Thursday)

High pressure ridging along the west coast will be the dominant
weather feature through the extended period. Daytime highs will
slowly be climbing Monday through Thursday reaching to around
normal. Extended models move a weak system over the north end of
the ridge and into the Pacific Northwest around Tuesday but keep
any precipitation north of the forecast area. Therefore...extended
period remains dry for now. Extended models hinting at a return to
a wetter pattern towards the end of next week but have been rather
inconsistent both run to run and model to model so confidence in
this change not especially high at this time.

&&

.Aviation...

VFR conditions expected to continue the next 24 hours. A frontal
system will begin to approach the area tonight, with light showers
spreading across the Coastal Range after midnight tonight. Light
winds across the Valley this morning will become southerly up to
10 kt. Along the mountains, SW wind gusts up to 30 kt will be
possible this afternoon.

Dang


&&

.STO Watches/Warnings/Advisories...
Winter storm watch from Friday morning through Saturday afternoon
above 5000 feet in the west slope northern Sierra Nevada...western
Plumas county/Lassen park.

&&

$$









000
FXUS66 KSTO 301036
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
336 AM PDT Thu Oct 30 2014

.Synopsis...
Mild weather for Today under upper level high pressure. A cold
front will impact interior northern California beginning tonight
then moving through norcal on Friday. The front will bring rain
and mountain snow along with cooler temperatures, and a slight
chance of thunderstorms. Showers are expected behind the front on
Saturday. Snow levels will lower to around 4500 ft Saturday
morning. Showers ending early Sunday with drier and milder weather
early next week.

&&

.Discussion...
Forecast area under mainly fair skies this morning under high
pressure ridge currently over the western U.S. A Pacific frontal
system will be pushing this ridge eastward over the next few days
bringing a significant change in the weather pattern. High
cloudiness being pulled northward into the area today ahead of an
offshore cold front will bring the first signs of weather pattern
change. Daytime highs will cool slightly from Wednesday but still
remain a little above normal for this time of year. The Pacific
cold front is forecast to move into northern California on Friday
bringing rain and mountain snow and enough instability for a
slight threat of thunderstorms especially over the western half of
the CWA. Model timing of this frontal system is becoming more
consistent amongst the models with current timing putting the
frontal boundary over the central valley around 00z Friday. Not
real good timing for trick or treaters who will be under the rainy
effects of the back edge of the front early Friday evening. By 12z
Saturday morning the main frontal band should be over the Sierra.
Colder air filtering in behind this front will bring a rapid drop
in snow levels. By 12z Saturday...snow levels over the CWA should
range from 4000 to 5000 feet. Showers are likely on Saturday under
upper level cyclonic flow. Saturday afternoon highs under the
cooler airmass are forecast to come in around 10 degrees below
normal. Mid range models move the upper trough axis into the Great
Basin by 12z Sunday morning. Rebuilding high pressure will bring
an end to any precipitation threat by Sunday afternoon along with
the beginning of a warming trend.

&&

.Extended Discussion (Monday through Thursday)

High pressure ridging along the west coast will be the dominant
weather feature through the extended period. Daytime highs will
slowly be climbing Monday through Thursday reaching to around
normal. Extended models move a weak system over the north end of
the ridge and into the Pacific Northwest around Tuesday but keep
any precipitation north of the forecast area. Therefore...extended
period remains dry for now. Extended models hinting at a return to
a wetter pattern towards the end of next week but have been rather
inconsistent both run to run and model to model so confidence in
this change not especially high at this time.

&&

.Aviation...

VFR conditions expected to continue the next 24 hours. A frontal
system will begin to approach the area tonight, with light showers
spreading across the Coastal Range after midnight tonight. Light
winds across the Valley this morning will become southerly up to
10 kt. Along the mountains, SW wind gusts up to 30 kt will be
possible this afternoon.

Dang


&&

.STO Watches/Warnings/Advisories...
Winter storm watch from Friday morning through Saturday afternoon
above 5000 feet in the west slope northern Sierra Nevada...western
Plumas county/Lassen park.

&&

$$









000
FXUS66 KSTO 300427
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
927 PM PDT Wed Oct 29 2014

.Synopsis...
Mild weather into Thursday afternoon. A cold front will impact northern
interior California Thursday night into Saturday with rain and
mountain snow along, cooler temperatures, and a slight chance of
thunderstorms. Snow levels will lower to around 4500 ft Saturday
morning. Drier and milder weather early next week.

&&

.Discussion...
The weak ridge over the area will push east on Thursday as the
next system approaches. The models have slowed the pace of the
system a little and both are still not quite in sink with one
another. The GFS is still a little bit faster that the NAM. Some
light precipitation may start over the northern areas and coastal
range late Thursday night out ahead of the main front as moisture
spreads over the region. The main band will come in on Friday
during the morning for the coastal range and parts of the western
Sacramento valley and then spread east for the afternoon. There is
a chance the far southeastern portions of the CWA may stay dry
during the day but that mean it is looking more likely that it
will be wet for the trick or treaters. The coastal range and the
western portions of the Sacramento valley will likely see showers
with possible thunderstorms developing behind the front for the
trick or treaters by late in the afternoon...while the San Joaquin
valley is looking wet with the front over on top of that area
through early evening.

Unstable air behind the front will give the interior a chance of
thunderstorms pretty much everywhere Friday night with most of the
activity expected Friday evening. The low will still be over the region
on Saturday with a chance of showers continuing and isolated
thunderstorms. Its not until Saturday evening when the low moves
far enough to the east that more stable air move over the area to
dry things out.

The slower pace will delay the lowering of snow levels slightly.
Snow levels look like they will stay high into early Friday
evening before lowering. Still about a foot of snow over the
higher elevations will be possible with lessor amounts down to
around 5000 feet through Saturday.

&&

.Extended Discussion (Sunday through Wednesday)

Trough shifts east Sunday with ridging forecast to return into
early next week leading to a return of dry northwesterly flow for
much of interior NorCal and a retreat of precipitation chances to
around the Oregon border.

Another frontal system is perched offshore west of 130W by
Thursday. This is out past our forecast time frame, but be prepared
for another frontal system Thursday night into Friday.

JClapp


&&

.Aviation...

VFR conditions expected to continue over the next 24 hours. Winds
generally below 10 knots.

&&

.STO Watches/Warnings/Advisories...
winter storm watch from friday morning through saturday
afternoon above 5000 feet in the west slope northern sierra
nevada...western plumas county/lassen park.

&&

$$









000
FXUS66 KSTO 292302
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
402 PM PDT Wed Oct 29 2014

.Synopsis...
Mild weather into Thursday afternoon. A cold front will impact northern
interior California late Thursday into Saturday with rain and mountain
snow along, cooler temperatures, and a slight chance of thunderstorms.
Snow levels will lower to around 4500 ft Saturday morning. Drier and
milder weather early next week.

&&

.Short Term Discussion (Tonight through Saturday)...
A warm afternoon with ample sunshine as current temperatures are
running about 5 to 12 degrees warmer than 24 hours ago. Tomorrow
will be another warm and mild day, but our weather pattern will
start changing late Thursday night.

A cold front will move into the coastal range late Thursday and
track eastward, impacting NorCal into Saturday. Main impacts will
likely occur on Friday due to morning/evening commutes and the
Halloween holiday. This morning`s CNRFC forecast for liquid
equivalent of precipitation was higher than previously forecast so
we have updated rain and snow totals in the afternoon package.
Valley rain totals are now closer to 0.30-0.50" while the
foothills range between 0.50-0.75" and the higher elevations peak
between 1-1.5". Snow levels will start off around 7000 ft Friday
morning then lower to around 6000 ft by Friday evening. By
Saturday morning, snow levels will continue to lower down to about
4500 ft. For snow accumulations, the greater impacts will occur above
5000 ft from Friday afternoon into Saturday morning with 4-8" of
snow accumulation at pass levels with locally higher amounts
closer to the crest. We have issued a Winter Storm Watch for the
Sierra above 5000 ft due to hazardous winter driving conditions
from snow accumulation. With the current models: timing of the main
precipitation still shows that the Valley and including Shasta
County will have peak precipitation on Friday afternoon (before 5
pm). Precipitation will continue into the evening, but be lighter.
The Sierra precipitation will peak Friday night. But keep in mind
that if the front stalls or speeds up on Friday, then these
general timing guidelines will change.

In addition to the rain and snow impacts, there is also some
instability associated with the cold frontal passage. There is a
slight chance for thunderstorms during the day Friday into Friday
night. Although rain can dampen trick-or-treating activities,
keep an eye and ear out for thunder and lightning as this would
make outside activities more dangerous. Please seek shelter if
thunderstorms develop. JBB

&&

.Extended Discussion (Sunday through Wednesday)
Trough shifts east Sunday with ridging forecast to return into
early next week leading to a return of dry northwesterly flow for
much of interior NorCal and a retreat of precipitation chances to
around the Oregon border.

Another frontal system is perched offshore west of 130W by
Thursday. This is out past our forecast time frame, but be prepared
for another frontal system Thursday night into Friday.

JClapp


&&

.Aviation...
VFR conditions expected to continue over the next 24 hours. Winds
generally below 10 knots.

&&

.STO Watches/Warnings/Advisories...
Winter Storm Watch from Friday morning through Saturday afternoon
above 5000 feet in the west slope Northern Sierra Nevada...western
Plumas county/Lassen Park.

&&

$$









000
FXUS66 KSTO 291608
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
908 AM PDT Wed Oct 29 2014

.Synopsis...
Mild weather into Thursday afternoon. A frontal system will impact
northern interior California late Thursday into Saturday with rain
and mountain snow along with cooler daytime temperatures. Snow
levels will lower to around 4000 ft Saturday morning. Drier and
milder weather early next week.

&&

.Discussion...
Today will be another mild day of weather with a mix of sunshine
and clouds. Daytime highs will be above normal by 5-10 degrees.
Valley highs peaking in the upper 70s to low 80s while mountain
highs range in the 60s and 70s.

Of course, the main weather story remains focused on the cold, wet
weather arriving late Thursday into Saturday which will impact
Halloween. Taking a look at the latest precipitation forecast (liquid
equivalent) from the CNRFC shows that amounts have increased by
about 30%. This means we`ll be updating our rain and snow amounts
for this storm in this afternoon`s forecast package after we make
minor changes to temperatures and snow levels. The main challenge
for the snow forecast will be timing of lowering snow levels. If
they drop faster than previously thought, this could increase snow
amounts. In terms of timing of the main precipitation, it still
looks as though the Valley and including Shasta County will have
peak precipitation on Friday afternoon (before 5 pm).
Precipitation will continue into the evening, but be lighter. The
Sierra precipitation will peak Friday night. Stay tuned for the
afternoon update.  JBB

.Previous Discussion...
Cold upper trough over the Gulf of Alaska
continues to work its way closer to the west coast where the upper
ridge will amplify and shift east over the next couple of days.
Moisture riding up and over the ridge from the southwest will
bring more clouds to the region today, but appears the main shower
threat will remain north of the region. Temperatures will remain
mild across the region today and Thursday.

Still appears that we`re on track for a change to cooler, breezier
weather with widespread precipitation on Friday as a frontal
system moves into NorCal. GFS and EC have trended a little slower
with the front as the upstream trough deepens offshore. Looks like
the front will move through the forecast area during the day on
Friday with scattered showers and a few thunderstorms behind the
front Friday evening.

Cool and unsettled weather continues Saturday as the upper trough
moves overhead, then gradually drier and milder weather returns
Sunday and early next week as the trough shifts east and
northwesterly flow develops across the region ahead of a building
ridge over the eastern Pacific.

Main weather impacts with the system will be the potential for
some significant snowfall across the higher elevations of the
northern Sierra Nevada, and whether trick-or-treaters will be wet.

&&

.Extended Discussion (Sunday through Wednesday)
Trough shifts east Sunday with ridging forecast to return into
early next week leading to a return of dry northwesterly flow for
much of interior NorCal and a retreat of precipitation chances to
around the Oregon border. Daytime highs will be below normal until
Tuesday when they start increasing to near seasonal values.


&&

.Aviation...

VFR conditions expected to continue over the next 24 hours. Winds
generally below 10 knots.

&&

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

$$










000
FXUS66 KSTO 291102
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
402 AM PDT Wed Oct 29 2014

.Synopsis...
Mild weather through early Thursday. A frontal system will impact
northern interior California late Thursday into Saturday with rain
and mountain snow along with cooler daytime temperatures. Snow
levels will lower to around 4000 ft Saturday morning. Drier and
milder weather early next week.

&&

.Discussion...
Cold upper trough over the Gulf of Alaska continues to work its
way closer to the west coast where the upper ridge will amplify
and shift east over the next couple of days. Moisture riding up
and over the ridge from the southwest will bring more clouds to
the region today, but appears the main shower threat will remain
north of the region. Temperatures will remain mild across the
region today and Thursday.

Still appears that we`re on track for a change to cooler, breezier
weather with widespread precipitation on Friday as a frontal
system moves into NorCal. GFS and EC have trended a little slower
with the front as the upstream trough deepens offshore. Looks like
the front will move through the forecast area during the day on
Friday with scattered showers and a few thunderstorms behind the
front Friday evening.

Cool and unsettled weather continues Saturday as the upper trough
moves overhead, then gradually drier and milder weather returns
Sunday and early next week as the trough shifts east and
northwesterly flow develops across the region ahead of a building
ridge over the eastern Pacific.

Main weather impacts with the system will be the potential for
some significant snowfall across the higher elevations of the
northern Sierra Nevada, and whether trick-or-treaters will be wet.
We`ll continue to monitor.

&&

.Aviation...
VFR conds expected to cont over the next 24 hours. Winds generally
below 10 knots.

&&

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

&&

$$






000
FXUS66 KSTO 290447
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
947 PM PDT Tue Oct 28 2014

.Synopsis...
Mild weather through early Thursday. A frontal system will impact
northern interior California late Thursday into Saturday with rain
and snow and cooler daytime temperatures. Snow levels will lower
to around 4000 ft Saturday morning. Drier and warmer weather early
next week.

&&

.Discussion...
A trough moving through the Pacific Northwest with the tail of the
front spreading some light showers or sprinkles over the northwest
part of the state. A few sprinkles may make its way into parts of
Western Shasta County overnight into early Wednesday otherwise
just expect clouds over the north tonight that will help to keep
temperatures a little warmer tonight.

As the next system approaches a ridge will start to amplify a
little over California on Wednesday. The models have slowed the
pace of the system a little but both are still not quite in sink
with one another. The GFS is still a little bit faster that the
NAM. Some light precipitation may start over the northern areas
and coastal range late Thursday night out ahead of the main front
as moisture spreads over the region. The main band will come in on
Friday during the morning for the coastal range and parts of the
western Sacramento valley and then spread east for the afternoon.
There is a chance the far southeastern portions of the CWA may
stay dry for the trick or treaters but most other areas should be
wet. The coastal range and far western end of the valley will
likely see showers with possible thunderstorms developing behind
the front.

Unstable air behind the front will give the interior a chance of
thunderstorms pretty much everywhere Friday night. The low will
still be over the region Saturday morning with a chance of showers
continuing and isolated thunderstorms. Its not until Saturday
evening when the low moves far enough to the east that more stable
air move over the area and dry things out. Conditions may become
breezy to windy from the northwest to north behind the front by
Sunday morning.


.Extended Discussion (Saturday through Tuesday)

Confidence continues to increase that we`ll see a significant
winter-like system affecting the region Halloween into Saturday.
Timing of the initial frontal system moving inland has improved
with the 00Z Monday operational runs of the GFS, EC and GEM
pointing toward daytime Friday for the onset of precipitation with
showers continuing Friday night and Saturday as the upper trough
moves overhead. Moderate amounts of precipitation, gusty winds and
potentially moderate amounts of snowfall for the higher
elevations of the northern Sierra will be possible with this
system.

Trough shifts east Sunday with ridging forecast to return into
early next week leading to a return of dry northwesterly flow for
much of interior NorCal and a retreat of precipitation chances to
around the Oregon border.

JClapp/Dang


&&

.Aviation...

VFR conditions expected to continue over the next 24 hours. Scattered
mid level clouds over the northern Sacramento Valley.

&&

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

$$









000
FXUS66 KSTO 282226
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
326 PM PDT Tue Oct 28 2014

.Synopsis...
Mild weather through early Thursday. A frontal system will impact
northern interior California late Thursday into Saturday with rain
and snow and cooler daytime temperatures. Snow levels will lower
to around 4000 ft Saturday morning. Drier and warmer weather early
next week.

&&

.Discussion...
Mostly sunny this afternoon except for some clouds over Shasta
County ahead of a weak front. Temperatures warming up into the
70s in the Valley and mid 50s to 60s in the mountains this
afternoon. These temperatures are near to a little above normal
for this time of year. Temperatures will warm up a little more on
Wednesday with highs in the mid 70s to low 80s in the Valley and
upper 50s to low 70s in the mountains. There is a slight chance of
showers for Western Shasta County as a weak front brushes by
tonight into early Wednesday, otherwise dry through early Thursday.
Temperatures will start to cool a little on Thursday as a system
approaches the area.

A colder and wet storm comes in late Thursday into Friday
(Halloween) spreading precipitation across interior Northern
California. Showers will continue Friday night and Saturday as
upper level trough moves over the area. Gusty Southerly winds are
expected on Friday as the front moves through the area. The
heaviest precipitation is expected in the north Friday morning and
the south in the afternoon. Precipitation is possible for the
trick or treaters Friday evening. Thunderstorms are possible with
instability behind the front Friday late afternoon and evening.
Valley precipitation amounts may generally be around a quarter to
half an inch and one to two inches in the Sierra and Shasta County
mountains. Snow levels will start out around 7000 to 8000 ft
Friday morning and lower to around 4000 ft Saturday morning. This
will bring winter driving conditions and possible travel delays
over the Sierra Friday into Saturday. High temperatures will only
be in the 60s in the Valley and low 30s to low 50s in the
mountains on Friday and Saturday which is several degrees below normal for
this time of year. With the colder airmass and some clearing
Friday night will be cooler.

The trough shifts east late Saturday into Sunday with ridging
forecast to return into early next week. A weak system may glance
by the far North, mainly Shasta County for a slight chance of
showers, otherwise dry conditions and warmer max temperatures are expected
Sunday through Tuesday. Temperatures are expected to warm up to
near normal on Tuesday with highs in the upper 60s to mid 70s in
the Valley and upper 40s to low 60s in the mountains.

&&

.Aviation...

VFR conditions expected to continue over the next 24 hours. A weak
disturbance will bring a slight chance of light rain showers to
the coastal mountains tonight, dry elswhere. Scattered mid level
clouds over the northern Sacramento Valley. Winds will remain
generally below 10 knots. EK

&&

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

$$









000
FXUS66 KSTO 281628
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
928 AM PDT Tue Oct 28 2014

.Synopsis...
Continued mild weather through Thursday. A frontal system will
impact northern interior California Friday (Halloween) and
Saturday with rain and snow and cooler daytime temperatures. Snow levels will
lower to around 4000 ft Saturday morning. Drier and warmer weather early
next week.

&&

.Discussion...
Chilly morning with temperatures in the 40s in the Valley and
generally 20s and 30s in the mountains under mainly clear skies.
These temperatures are near to a few degrees below normal for this
time of year. Temperatures will warm up into the 70s in the Valley
and mid 50s to 60s this afternoon with sunny skies under a weak
ridge of high pressure. These temperatures are near to a little
above normal for this time of year. Temperatures will warm up a
little more on Wednesday with highs in the upper 70s to low 80s in
the Valley and upper 50s to low 70s in the mountains. There is a
slight chance of showers for Western Shasta County as system move
by to the north tonight, otherwise dry through early Thursday. A
colder and wet storm comes in late Thursday into Friday
(Halloween) spreading precipitation across interior Northern
California. Showers will continue Friday night and Saturday as
upper level trough moves over the area. Gusty Southerly winds are
expected on Friday as the front moves into the area. Valley
precipitation amounts may be around 0.20 inches to half an inch
and one to two inches in the Sierra and Shasta County mountains. Snow
levels will start out around 7000 to 8000 ft Friday morning and
lower to around 4000 ft Saturday morning. This will bring winter
driving conditions and possible travel delays over the Sierra
Friday and Saturday.Trough shifts east Sunday with ridging
forecast to return into early next week leading to a return of dry
northwesterly flow for much of interior NorCal and a retreat of
precipitation chances to around the Oregon border.


&&

.Aviation...

Flat high pressure over west coast will bring VFR conditions next
24 hours. Winds generally below 10 knots.

&&

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

$$









000
FXUS66 KSTO 281144
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
444 AM PDT Tue Oct 28 2014

.Synopsis...
Continued mild weather through Thursday. A frontal system will
impact interior northern California Friday (Halloween) and
Saturday with valley rain and Sierra snow.

&&

.Discussion...
Mainly clear skies across the interior of NorCal early this
morning. A chilly start to the morning with current temperatures
ranging from the mid 20s to lower 30s in the colder mountain
valleys to the 40s to lower 50s elsewhere.

A flat ridge will be over the region today into Thursday providing
dry weather and mild daytime temperatures for most of the area.
Weather systems skirting by to the north may bring some showers to
far northwest CA, but the remainder of interior NorCal is expected
to remain dry.

Confidence remains rather high for seeing a significant winter-
like system affecting the region Halloween into Saturday. Model
timing of the initial frontal system continues to point toward
it moving inland on Friday with showers continuing Friday night
and Saturday as the upper trough moves overhead. Moderate amounts
of precipitation, gusty winds and potentially moderate amounts of
snowfall for the higher elevations of the northern Sierra will be
possible with this system.

Trough shifts east Sunday with ridging forecast to return into
early next week leading to a return of dry northwesterly flow for
much of interior NorCal and a retreat of precipitation chances to
around the Oregon border.

&&

.Aviation...
Flat high pressure over west coast will bring VFR conditions next
24 hours. Winds generally below 10 knots.

&&

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

&&

$$






    US Dept of Commerce
    National Oceanic and Atmospheric Administration
    National Weather Service
    1325 East West Highway
    Silver Spring, MD 20910
    Page Author: NWS Internet Services Team
Disclaimer
Information Quality
Credits
Glossary
Privacy Policy
Freedom of Information Act (FOIA)
About Us
Career Opportunities