888
FXUS66 KSTO 232053
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
153 PM PDT Sun Mar 23 2025

.SYNOPSIS...
Warm and dry weather is expected this weekend and into early this
week. Cooler and periods of active weather return by mid to late
this week with breezy southerly winds.

&&

.DISCUSSION...
Ridging builds across interior NorCal today through early this
week, resulting in drier and warmer conditions across the area.
Daytime temperatures will be 10 to 20 degrees above normal (Today-
Tuesday) with widespread Minor HeatRisk across the Valley on
Monday and Tuesday. Valley temperatures are forecast to be in the
mid to upper 70s this afternoon, with highs in the low to mid 80s
early this week. Warmest temperatures are still expected on
Tuesday, with the National Blend of Models indicating a 75-100%
probability of high temperatures greater than 80 degrees across
the Valley and portions of the Delta and foothills. Blended
guidance suggests a slight cooling trend by Wednesday, with the
latest NBM projecting highs in the low 70s to around 80 for the
Valley, Delta, and foothills. Northerly winds will be breezy at
times today, with gusts 15 to 20 mph along the I-5 corridor in the
Sacramento Valley. Winds will gradually diminish in the afternoon
hours.

Ensembles depict southwest flow developing on Wednesday ahead of
an approaching trough. This system is expected to bring chances
for light, low-impact precipitation mainly over the mountains
later Wednesday through early Friday morning. In addition, the
NBM shows a 15-30% probability of thunderstorm development
Wednesday afternoon and evening, mainly across portions of the
northern Sacramento Valley, with less than a 10% chance elsewhere
in the Valley. Gusty southerly winds are also expected with this
system on Wednesday, particularly across portions of the
northern/central Sacramento Valley and mountains. The NBM projects
a 20-50% probability of wind gusts greater than 35 mph across the
northern and central Sacramento Valley on Wednesday.

&&

.EXTENDED DISCUSSION (Thursday THROUGH Sunday)...
A shortwave trough moves across the region Thursday into Friday,
with light precipitation mainly over the mountains. Amounts
continue to trend lighter with this system. WPC guidance suggests
0.10-0.33" of precipitation over the Sierra north of US Hwy 50,
and up to 0.66" over the mountains of Shasta County. Much of the
Sacramento Valley is expected to be see less than 0.10" (except
for the northern Sacramento Valley with up to 0.10"-0.20"). This
will be a fairly warm system as well, with snow levels starting
above 8000 feet on Wednesday before lowering to around 5000-6000
feet by Thursday. This will allow for a light dusting of snow with
up to an inch along higher terrain. Gusty southerly winds are
also expected with this system on Thursday. The NBM shows a
slightly increased probability of thunderstorm (now 15-20%) on
Thursday afternoon/evening across portions of the northern
Sacramento Valley and adjacent foothills and mountains. Other than
some light showers over the mountains north of I-80 on Friday, a
brief lull in precipitation is expected through Saturday
afternoon. Ensembles and clusters indicate unsettled and
potentially wetter weather arriving Sunday and continuing through
Monday, with possible mountain travel issues, but strength and
timing remain uncertain at this point.

&&

.AVIATION...
VFR conditions expected to continue over the next 24 hours.
Locally breezy north to east wind gusts up to 15-20 kts are
expected across portions of the Sacramento Valley and over the
Sierra through 00z Monday. Elsewhere, surface winds less than 12
kts are expected.

&&

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

$$