Cold in California, May 25, 2024

Area Forecast Discussion
National Weather Service Sacramento CA
309 PM PDT Sat May 25 2024

.SYNOPSIS...
Temperatures warm back up to near to slightly above normal with
areas of minor HeatRisk from Sunday into the week ahead. Lighter onshore
flow looks to persist through midweek before dry, northerly flow
with lower humidity returns for the late week period.

&&

.DISCUSSION...
There was an impressive marine layer intrusion through the Delta
and the Central Valley this morning, with low stratus spreading as
far north as Redding. This brought breezy onshore winds, with the
low clouds persisting into the early afternoon in some areas.

With the cool and cloudy start to the morning, afternoon
temperatures in the those areas are relatively cool. As a result,
Valley high temperatures look to remain firmly in the 70s, with
50s to 60s at higher elevations. The onshore flow pattern is
expected to continue but will weaken overnight, with lighter winds
into Sunday. The marine layer has mixed out and is much more
shallow, so not expecting an influx of low clouds for early
Sunday. High pressure ridging builds in Sunday with a strong
warming and drying trend beginning. High temperatures for Sunday
afternoon rise to near normal for this time of year, with Valley
high temperatures in the mid to upper 80s and 60s to mid 70s at
higher elevations.

The upper level ridge axis is expected to strengthen but will
remain centered to the east over the Rocky Mountains. This along
with trough developing over the Pacific Northwest limit cooling
and continue some lighter onshore flow into mid week. High
temperatures for Memorial Day look to reach the upper 80s to low
90s in the Valley and 70s to low 80s at higher elevations, with
slightly cooler values forecast on Tuesday.

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.EXTENDED DISCUSSION (Wednesday THROUGH Saturday)...
Overall, warm, dry, and breezy conditions are expected to prevail
through the extended period. There is some forecast uncertainty
in temperatures, though, with a roughly 10 degree variance in
current forecast high temperatures. Some notable uncertainty is
remains in the forecast across the mid to late week period. Latest
cluster analysis is leaning toward (~60% of ensemble membership)
a solution of ridging aloft building in through the late week
period, while still nonzero membership (~40%) indicates a
continuation of broad troughing aloft. While the overall
differences would be somewhat subtle, the former solution would
result in dry northerly surface flow returning and temperatures
warming through the end of the week. In contrast, the latter
solution would yield a more or less stagnant weather pattern with
onshore flow persisting and temperatures remaining slightly above
normal.

&&

&&

.AVIATION...
Mainly VFR conditions next 24 hours, except for local MVFR
ceilings across portions of the Delta and Valley lingering through
the afternoon hours. Winds generally less than 10 kts through 23Z
Saturday, then local southwest wind gusts 15-25 kts in the Delta
and Sacramento Valley, and west- northwesterly 15-25 kts across
the northern San Joaquin Valley.

&&

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