452
FXUS66 KSTO 232023
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
1223 PM PST Thu Jan 23 2025

.SYNOPSIS...
Dry weather and cold, foggy mornings over the next few days.
Gusty north to east winds this weekend are the main issue, along
with the potential for light foothill rain and mountain snow.

&&

.DISCUSSION...
Dry weather continues through at least Friday, with cool morning
temperatures. A number of locations in the Valley and Delta dropped
to around freezing this morning, such as Sacramento Executive
Airport at 31 degrees and Stockton at 30. High pressure ridging
peaks today, with highs this afternoon rebounding into the mid to
upper 60s, highest over the northern Sacramento Valley. Highs
will trend cooler as the upper level ridge weakens and a shortwave
trough (inside slider) approaches this week and then drops into
the region over the weekend. By Saturday highs will be near normal
levels, with upper 50s to low 60s for the Valley.

Valley low temperatures are forecast remain in the 30s through
the end of the week, with a 15 to 30% chance of below freezing
temperatures Friday morning for rural portions of the Valley. Low
temperatures in the Valley and Delta will gradually warm to the
mid 30s to low 40s heading into the weekend. Patchy morning fog
and frost are also expected.

The upper trough(inside slider) will bring gusty north to east
winds to the area over the weekend, so this will be the main
weather impact for the short term forecast. A Wind Advisory has
been issued for the northern mountains and adjacent foothills, as
well as western portions of the Sacramento Valley from 10 PM PST
Friday to 10 AM PST Sunday. For the mountains and northeast
foothills expect northeast to east winds 20 to 30 mph with gusts
to 40 to 55 mph. For western portions of the Sacramento Valley,
north winds 15 to 25 mph with gusts 35 to 45 mph are forecast.
Winds will be weaker by Sunday afternoon, but will still be gusty.

Inside sliders such as this shortwave trough move across land have
limited moisture to work with, so precipitation will be limited. A
few light rain showers will be possible over the northern San
Joaquin and eastern side of the southern Sacramento Valley on
Saturday as the system passes through, but most precipitation will
be over the Sierra and foothills. Rain and snow have trended a
little higher with the latest National Blend of Models, but are
generally expected to be limited. Rainfall amounts in the
foothills are forecast to be around a tenth of an inch. Snowfall
will be relatively light, though cool temperatures could allow a
dusting of snow down to the upper foothills, for elevations
around 3000 feet. Higher elevations could see 1 to 2 inches from
HWY 50 northward, while the Sierra crest in Tuolumne County could
see up to 4 inches of snow.

&&

.EXTENDED DISCUSSION (Monday THROUGH Thursday)...
Ensemble guidance and cluster analysis show the low pressure
system progressing further south and east, and ridging building
back in over NorCal. This will result in dry weather and cold
morning temperatures for early to mid next week. Morning low
temperatures will drop back into the 30s, with more widespread
chances at near or below freezing Valley temperatures and frost.
Daytime highs will be near to slightly above normal, with Valley
temperatures reaching the high 50s to low 60s, and 40s to 50s at
higher elevations. On Thursday, there`s potential for the approach
of a weak trough, though this far out there is much uncertainty
around what that could mean for interior NorCal beyond slightly
cooler temperatures. The Climate Prediction Center (CPC) 8-14 day
outlook has much of interior NorCal under equal chances for above
or below normal precipitation. Be sure to stay tuned for forecast
updates as we get closer!

&&

.AVIATION...
Generally VFR conditions prevail across interior NorCal next 24
hours, although some patchy MVFR/IFR in Valley BR/FG are possible
from 06z through 17z tomorrow. Winds will be less than 12 kts
through early tomorrow.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from 10 PM Friday to 10 AM PST Sunday for Central
Sacramento Valley-Mountains Southwestern Shasta County to
Western Colusa County-Northeast Foothills/Sacramento Valley-
Northern Sacramento Valley-Shasta Lake Area / Northern Shasta
County-Southern Sacramento Valley-West Slope Northern Sierra
Nevada-Western Plumas County/Lassen Park.

&&

$$