Area Forecast Discussion
Issued by NWS Sacramento, CA

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000
FXUS66 KSTO 162130
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
230 PM PDT Sat Mar 16 2024



.Synopsis...
Warm and dry weather through the weekend and into early next week.
Unsettled weather and cooler temperatures return for the end of
next week.

&&

.Discussion...
There is a 100% chance of abundant sunshine and clear skies this
afternoon (per GOES West visible imagery)! Warm temperatures and
dry weather will continue over this St. Patrick`s Day weekend as
an upper level ridge builds over Northern California. Temperatures
will follow a gradual warming trend this weekend and into early
next week with highs 5 to 10 degrees above normal. Winds will be
breezy at times through the Delta and over the Sierra, otherwise
light winds everywhere else.

A swath of mid-level moisture wrapping around the weakening low
centered over northwestern Arizona will promote the formation of
high-based towering cumulus clouds over the foothills and
mountains Sunday-Tuesday. On Tuesday, increased westerly flow and
additional instability over southern Tuolumne County combined
with the mid-level moisture has a 5-15% chance of generating
isolated mountain thunderstorms per the National Blend of Models
(NBM). Confidence is low at this time to include in the forecast,
but we`re closely monitoring this trend as forecast confidence
increases, so stay tuned for additional updates!


&&


.EXTENDED DISCUSSION (Wednesday THROUGH Saturday)...
Upper level ridging is expected to break down over the region and
move off towards the east. A short wave trough is then forecast
to approach the area, and spread light precipitation mostly into
the northern Sacramento Valley on Thursday. A stronger short wave
is then projected to move into the region Friday into early
Saturday and bring more widespread precipitation for interior
NorCal, with impacts mainly for the northern Sacramento Valley and
the Sierra. Clusters are in disagreement on timing and amplitude
of the trough, so forecast uncertainty remains high at this time
regarding onset and intensity of precipitation. Afternoon model
runs has increased precipitation totals across the northern Sac
Valley and the Sierra. The National Blend of Models (NBM)
currently has a 30-60% probability of 1" inch of rainfall or more
from Redding and areas north as well as in the Sierra, mainly
north of I-80 from Thursday into the weekend. Snow levels will be
around 6000 feet and higher on Thursday, then lowering to around
5000 feet on Saturday. NBM snowfall probabilities for 6" inches or
more are around 30-50% along I-80 and US-50 for elevations above
6000 feet from Thursday through Saturday. Check back for forecast
updates as we move into next week.


&&


.AVIATION...
VFR conditions expected to prevail over interior NorCal. Variable
surface winds mainly below 10 knots over the next 24 hours.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$


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