Area Forecast Discussion
Issued by NWS Sacramento, CA

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

FXUS66 KSTO 231920

Area Forecast Discussion
National Weather Service Sacramento CA
1120 AM PST MON NOV 23 2015

Dry and mild weather will continue through this afternoon with
above normal temperatures. A cold Pacific storm will bring heavy
snow in the mountains with snow extending down into the upper
foothills late Monday into Wednesday. Dry and cold weather
expected Thanksgiving.


Another pleasant, mild day today before a cold storm from the Gulf
of Alaska approaches. This storm will bring heavy snow to the
mountains extending down into the foothills (2500 feet), impacting
communities such as Grass Valley. Very heavy snow is possible
Tuesday afternoon and early evening in the mountains with whiteout
conditions possible in intense snow. Motorists are strongly urged
to avoid travel during this time period. Plan to upgrade the
Winter Storm Watch to a Winter Storm Warning shortly, with a
Winter Weather Advisory for the northern mountains/Burney Basin.

This storm will come in two parts, with the
main front on Tuesday and then showers in cold are behind the
front late Tuesday into Wednesday. The main frontal band will
move into the area Tuesday morning, spreading from north to south,
with highest intensity snow in the mountains in the afternoon and
early evening. Snow levels will start around 4000 feet for the
northern Mountains, 5000 feet for the Sierra Tuesday morning, are
then expected to drop into the foothills (2500 feet) late Tuesday
night. Snow levels could lower to 2000 feet or locally lower in
showers Wednesday morning. Showers through the day Wednesday will
add some additional mountain accumulation, and are expected to bring
the main impact to foothill communities. The showers should be
mainly over by around sunset Wednesday, except for a few
lingering ones over the Sierra crest.

Another concern is Tuesday afternoon thunderstorms which have been
added to the forecast. Clearing behind the front along with cold
air aloft could bring enough instability for thunderstorms in the
Sacramento Valley, mainly north of I80. There is enough shear for
some isolated stronger thunderstorms to develop. There is also the
possibility for some convection into Wednesday. EK


The cold airmass and light wraparound flurries over the Sierra
will linger into the weekend as the system slowly shifts east.
Temperatures will remain quite cool with the potential for
widespread near freezing temperatures in the Valley during the
late night and morning hours. Temperatures in the mountains and
mountain valleys could be quite cold dropping to teens and single
digits. A limiting factor for cold morning temperatures will be
northerly winds, which could keep the atmosphere more mixed and
warmer, along with some cloud cover.

Uncertainty remains for early next week as there is very little
consistency in model solutions at this time.


SWly flow alf as upr low movs thru tda. Genly VFR conds ovr Intr
NorCal nxt 24 hrs exc lcl MVFR/IFR in BR/FG in Cntrl Vly fm vcnty
KMYV Swd into SJ Vly til arnd 18Z-20Z. Sfc wnds genly lgt.

.STO Watches/Warnings/Advisories...
Winter Storm Warning from 7 AM Tuesday to noon PST Wednesday for
Motherlode-Northeast Foothills/Sacramento Valley-West Slope
Northern Sierra Nevada-Western Plumas County/Lassen Park.

Winter Weather Advisory from 7 AM to 6 PM PST Tuesday for Burney
Basin / Eastern Shasta County-Mountains Southwestern Shasta
County to Northern Lake County-Shasta Lake Area / Northern
Shasta County.


$$ is the U.S. government's official web portal to all federal, state and local government web resources and services.