Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 201052

Area Forecast Discussion
National Weather Service Sacramento CA
352 AM PDT Tue Mar 20 2018

Wet weather returns today and continues into the weekend.


Clouds have increased overnight across interior NorCal. Current
temperatures are milder (5-15 degrees warmer) compared to 24 hours
ago and generally range from the lower 20s in the mountain valleys
to the upper 40s to mid 50s across the Central Valley.

The low along 140W is beginning to slowly shift east. Satellite
imagery shows a wide swath of clouds and deep moisture (TPW > 1.5
inches) approaching California from the southwest. Southern
portions of the forecast area may see some sprinkles this morning
with light precipitation becoming more likely later this
afternoon. Initially, NorCal will be on the northern periphery of
heavier precipitation as the focus will be into SoCal.

However, precipitation will be on the upswing across NorCal tonight
as warm-advection and moisture increase further. Snow levels will
high limiting accumulating snow to just the highest elevations.

Heavier precipitation is forecast to begin later Wednesday and
continue Thursday as deeper moisture moves north into NorCal ahead
of the approaching cold front and upper trough. The trend in the
models has been a little slower with the trough allowing potential
for higher QPF spreading further north. Snow levels will initially
be rather high, 6500-7500 feet, but will tumble to below 4000
feet behind the front by later Thursday. Periods of moderate to
heavy precipitation will be possible, particularly over the
mountains. Gusty winds are also possible on Wednesday across the
region. A few thunderstorms will also be possible Wednesday and

Precipitation forecast to taper Thursday night before the next
system moves in on Friday.


Upper low/trough along the West Coast with cyclonic flow will keep
showers in the forecast over Interior NorCal Saturday. Snow levels
Saturday will be low, 1500-2500 feet. Precipitation for the most
part looks light and focused more over the foothills and mountains.
Sunday is trending dry and warmer, as upper ridging develops with
dry northwest flow. Dry weather continues early next week, with a
warming trend as heights increase over Interior NorCal.


Dtrtg conds ovr Intr NorCal this aftn into eve as pcpn sprds ovr
fcst area. Areas MVFR/IFR conds aft 00z in rain and mtn snow. Sn
lvls AOA 060. Lcl S-SW sfc wnd gsts to 25 kts ovr hyr trrn tngt
into Wed mrng.


Winter Storm Watch from Thursday morning through late Thursday
night for West Slope Northern Sierra Nevada-Western Plumas
County/Lassen Park.


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