483
FXUS66 KSTO 062056
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
1256 PM PST Mon Jan 6 2025

.SYNOPSIS...
A few light High Sierra showers tonight into early Tuesday,
otherwise dry conditions prevail with a gradual warming trend.
Gusty north to east winds develop tonight and persist through
early Wednesday, strongest on Tuesday and in the mountains.

&&

.DISCUSSION...
Latest GOES-West visible satellite imagery depicts mostly sunny
skies across interior northern California on this Monday
afternoon. Patchy fog from the Delta and vicinity from morning has
burned off and visibilities have improved across that area.
Temperature observations are currently in the 50s to low 60s in
the Valley, and in the 40s to 50s in the foothills and mountains,
valid at 1245 PM PST.

Dry conditions will prevail this week, outside of a few High
Sierra showers or snow showers tonight through early Tuesday.
Little to no impacts are expected as precipitation is fairly light
and confined to the higher elevations of the Sierra Crest.
Gradually warming temperatures are also favored this week, with
high temperatures in the 50s to 60s for the Valley.

An upper level trough will dig southward over the Great Basin
early this week, with upper level ridging over the Eastern
Pacific. A strong pressure gradient will allow for gusty north to
east winds to develop tonight and persist through Wednesday
morning. The National Blend of Models (NBM) shows a 70-90%
probability of wind gusts of 60 mph or greater over the higher
peaks of the Sierra Nevada. A Wind Advisory remains in effect for
portions of the West Slope Northern Sierra Nevada, Western
Plumas/Lassen Park, and Northeast Foothills including Highway
70/Jarbo Gap through Wednesday morning. The Wind Advisory now
includes the far western portion of the Southern Sacramento
Valley, Carquinez Straight, and Delta where the NBM shows a
50-80% probability of 40 mph wind gusts or greater from the north.
These gusty winds can make driving difficult, especially for high
profile vehicles. People in the mountains should use extra
caution while driving, be alert during outdoor activities, and
secure any loose outdoor objects such as holiday decorations.
Winds are then projected to diminish on Wednesday, however
periodically breezy north to east flow will continue through the
rest of the week. Be sure to stay up to date with the latest
forecast at weather.gov/sto!

&&

.EXTENDED DISCUSSION (Friday THROUGH Monday)...
Ridging in the Eastern Pacific will be the dominate synoptic
feature through the extended forecast period. High temperatures
will be near to slightly above normal Friday through Monday, with
Valley highs in the upper 50s to low 60s and 40s and 50s in the
foothills and mountains. Ensemble guidance suggests several weak
shortwaves to move through the northern Sierra and southern
Cascades, however little to no moisture will be associated with
them, so forecast remains dry. As a shortwave trough digs through
the mountains on Saturday morning into Monday, weak PGF develops
leading to periods of breezy/gusty north to east winds, with
strongest winds currently projected by the NBM to be in the
western Sacramento Valley along the I-5 corridor and in the
canyons/gaps of the foothills and Sierra. Cluster guidance
continues to show an extended period of dry weather beyond Monday.

&&

.AVIATION...
Mainly VFR conditions over the next 24 hours except for MVFR/IFR
conditions from BR and FG in the Northern San Joaquin Valley from
06Z Tuesday to 19Z. Northerly surface winds are expected to be
15-25 knots with 30-40 knots gusts in the Valley and Foothills for
the next 24 hours with northeast to east gusts up to 60 knots
over the Sierra Nevada.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from 10 PM this evening to 7 AM PST Wednesday for
Carquinez Strait and Delta-Northeast Foothills/Sacramento Valley-
Southern Sacramento Valley-West Slope Northern Sierra Nevada-
Western Plumas County/Lassen Park.

&&

$$