Area Forecast Discussion
Issued by NWS Sacramento, CA

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000
FXUS66 KSTO 241622
AFDSTO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
922 AM PDT Fri Apr 24 2015

.Synopsis...
Lingering scattered showers over the Sierra today and mainly dry
elsewhere. A fast moving wet system pushes across the area
tonight and Saturday morning bringing at least light precipitation
most areas. High pressure brings dry conditions Sunday through
next week. Warmest temperatures Monday with slight cooling trend
through the end of the week.

&&

.Discussion...
Lingering showers over the Sierra with snow levels around 7000 ft this
morning. A colder and wet system will move in tonight into
Saturday bringing more widespread precipitation and lower snow
levels. Temperatures this morning are generally similar to a few
degrees cooler in the valley compared to yesterday morning but
about 10 degrees cooler in the mountains. Afternoon high
temperatures are expected to be about 5 to 15 degrees cooler than
yesterday with the most cooling in the mountains and the Northern
Sac Valley. More widespread precipitation is expected to enter
interior Northern California around 9 pm tonight. Precipitation is
expected to become more showery North of I-80 around sunrise and
south of I-80 by noon. Although isolated to scattered showers are
possible through Saturday afternoon. Showers may linger over the
Sierra into the evening. Snow levels are expected to drop to
around 5500 ft around midnight. Snow accumulations of several
inches are expected over the passes with around a foot possible
over the Sierra peaks.  Snow may cause travel delays over the
Sierra with slick roads and reduced visibilities. Rainfall amounts
are generally expected to be a tenth to around a third of an inch
in the Valley and Coastal Range, and around half to 0.75 inches in
Sierra foothills and around an inch in the Sierra. Afternoon
temperatures on Saturday are expected to reach the upper 60s to
low 70s in the Valley and mid 30s to low 50s in the mountains.
These temperatures are generally a few degrees below normal for
this time of year. Temperatures warm up Sunday afternoon by around
10 degrees compared to Saturday as high pressure builds into the
area along with Northerly winds. Sunday afternoon highs are
expected to be in the upper 70s to low 80s in the Valley and upper
40s to upper 60s in the mountains which is generally a few degrees
above normal for this time of year. Sunday and Monday should be
dry with high pressure over the area.

.Extended Discussion (Tuesday through Friday)

The high pressure ridge will begin to weaken and shift eastward on
Tuesday as another trough approaches the Pacific NW and far
NorCal. Temperatures will still be 5-15 degrees above normal in
the extended forecast, but there will be a gradual cooling trend
Tuesday through Friday as a secondary trough also moves towards
the west coast. Extended models differ slightly on timing of these
troughs, but the moisture will remain north of our forecast area so
weather will be dry during the cooling trend.  JBB


&&

.Aviation...

Mainly VFR conditions today, except for local MVFR/IFR conditions
over the mountains with showers. A Pacific storm system will move
through the area late this evening and tonight, bringing
widespread rain across the Valley. Mainly VFR/MVFR conditions
expected as the system moves through. Over the mountains,
widespread IFR/LIFR conditions expected tonight into Sat morning.
Snow levels expected to be around 5500 ft.

South to west winds expected to increase to 10-18 kt across the
Valley today. Gusty conditions possible near the Delta and over
the higher elevations.

Dang


&&

.STO Watches/Warnings/Advisories...
winter weather advisory from 11 pm this evening to 5 pm pdt
saturday above 5500 feet in the west slope northern sierra
nevada...western plumas county/lassen park.

&&

$$







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