Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 261752

952 AM PST Wed Nov 26 2014

Dry and mild weather is expected through Thanksgiving as high
pressure covers the region. Rain is expected to return to the
region by late Friday and continue into early next week. Snow
across the mountains is likely to cause travel difficulties for
the holiday weekend and into early next week.


Patchy fog in the valleys this morning but starting to dissipate
and visibilities improving around 9 am. Mostly sunny skies (with
some mid and high clouds) and above normal temperatures today with
another day under ridge of high pressure. Temperatures this
afternoon are expected to peak in the mid to upper 60s in the
Central Valley and foothills and 50s to mid 60s in the mountains.
Increasing clouds for Thanksgiving as a storm system approaches
but temperatures will remain above normal. Patchy fog in the
valleys will also return for Thanksgiving morning.

The weather will turn cooler and wetter Friday into next week as
several storm systems move through the area. Temperatures start to
cool on Friday as the ridge shifts east, with temperatures in the upper
50s to mid 60s in the Valley and mid 40s to 50s in the mountains.
Precipitation is expected to start moving into the Coastal range
Friday morning and gradually spread southeast across the area to
around the I-80 corridor Friday evening and farther south into the
Northern San Joaquin Valley Saturday morning. Temperatures will
cool to near normal on Saturday with highs in the mid 50s to low
60s in the Valley and mid 30s to 40s in the mountains. Snow levels
are expected to be around 7500 ft Friday and lower to around 6000
feet Saturday. A few inches of snow are possible in the Sierra
with around a foot possible for the top of Mt. Lassen. Rainfall
totals for Friday and Saturday are expected to be around 1.5
inches around Redding to around 0.75 inches around Sacramento and
around a third of an inch in the Northern San Joaquin Valley.
Generally around 1 to 2.5 inches for the mountains...mainly north
of I-80.

.Extended Discussion (Sunday through Wednesday)

Development of a deep, closed upper level low off the CA coast
late this holiday weekend threatens to bring significant
rain/mountain snow to interior NorCal into early next week. The
NCEP GEFS shows a 70% probability of at least 1 inch of mountain
precipitation, and a 40% probability of at least 2 inches. The
GFS/EC/GEM all show warm frontal type precip Sunday with the main
low still west of 130W.

Mid range models have been showing several inches of rain
from Saturday through Monday; however, the amounts/timing could
be in jeopardy as the models have shown signs of diverging. The
GFS and GEM show the low slowly filling and progressing inside
130W on Monday with decent amounts of precipitation. On the other
hand, the EC cuts off the low west of 130W with little movement
eastward until Tuesday. While a multi-day precip event for NorCal
exists, model differences in timing could result in greater,
lesser, or delayed results/impacts. In spite of the EC diverging,
we have kept precipitation amount relatively constant. For now,
the heaviest precip forecast is still expected to occur from
Sunday night through Monday. Significant snow may accompany this
wet period. Light snow accumulation may occur down to 4500-5000 ft
and 5-10 inches of snow may accumulate above 6000 ft with 12-36
inches above 7000 ft. The higher end amounts would likely occur
over Lassen Park and into western Plumas county.    JClapp



Early morning patch IFR/LIFR fog/stratus conditions in the
Central Valley and mtn valleys/basins. Dewpoints increased from
yesterday, so expect to see more fog. Most will be patchy and
relatively shallow.     JClapp


.STO Watches/Warnings/Advisories...

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