Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 232145
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
245 PM PDT Thu Mar 23 2017



.Synopsis...
Rain and mountain snow returns tonight and Friday. Sierra snow
impacts likely late tonight into Saturday. Another system possible
Sunday and Monday with mountain travel impacts. Brief break in
precip mid weekend but more precipitation early next week.

&&

.Discussion...
Pacific storm system now approaching the coast will move into
NorCal late tonight bringing a return to precipitation. The
heaviest amounts will fall during the day Friday. Valley rainfall
amounts will range from 1-2 inches Redding area to 0.25-0.50
Stockton/Modesto. Mountain precip amounts will be 1-2 inches
liquid. Snowfall amounts 8-14 inches above 4500 feet with up to
two feet highest elevations. Expect significant travel delays over
the Sierra. Activity will turn more showery Friday afternoon with
mesoscale models showing thunderstorms over the northern
Sacramento valley. Tightening pressure gradient will bring a few
40 mph south wind gusts up the Sacramento valley...Stockton to
Redding...strongest central valley around Red Bluff.

Models continue the trend of drier weather Saturday with weak
ridge northwest flow. Next system will drop through Norcal Sunday
afternoon through Monday and looks to be slightly drier but colder
than Friday system. Snow levels look to be 4000 feet or lower.

&&
.EXTENDED DISCUSSION (Monday THROUGH Thursday)

Showers will linger on Monday as upper level wave moves through.
Have boosted snow amounts a bit during the day with snow levels
around 5000 feet. Modest additional accumulations likely but will
probably be enough to cause a few travel delays. Have also
introduced the possibility of thunderstorms during the
afternoon/evening hours. This will hinge on the amount of clearing
in the morning but models are indicating some decent instability.
Ridging then builds in for Tuesday and Wednesday with warming
temperatures. Models continue to show another system dropping into
the area from the Gulf of Alaska on Thursday but disagree on the
details. At this time, best chances for precipitation looks to lie
across northern and eastern portions of the area.

CEO

&&

.AVIATION...

Next system moves into NorCal tonight into Friday. VFR conditions
through this evening then local MVFR/IFR conditions after 12z
Friday with precipitation. Winds will increase on Friday with
gusts to around 25 kts at TAF sites.


&&

.STO WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning from 11 PM this evening to 5 AM PDT
Saturday for West Slope Northern Sierra Nevada-Western Plumas
County/Lassen Park.

Wind Advisory from 9 AM to 7 PM PDT Friday for Carquinez Strait
and Delta-Central Sacramento Valley-Motherlode-Northeast
Foothills/Sacramento Valley-Northern Sacramento Valley-Northern
San Joaquin Valley-Southern Sacramento Valley.

Winter Storm Warning from 11 PM this evening to 5 AM PDT
Saturday for Shasta Lake Area / Northern Shasta County.

&&

$$



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