329
FXUS66 KSGX 012143
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
143 PM PST Mon Dec 1 2025

.SYNOPSIS...
Weak to locally moderate Santa Ana winds continuing today, waning
this evening with onshore flow returning Tuesday afternoon.
Chances increase for another round of weak to moderate Santa Ana
winds late Wednesday into Friday, peaking late Wednesday into Thursday.
Gradual warming Thursday into next weekend with highs near
seasonal normals.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

On the heels of the inside sliding upper trough now ejecting into
the Great Plains, a 1032 mb surface high pressure has pushed through
the Great Basin, establishing our offshore pressure gradient with
weak to moderate Santa Ana winds already in place. The strongest
winds remain primarily through mountain and just below passes where
wind gusts of 30-50 mph have been observed with 20-30 mph gusts
stretching into inland valleys. The offshore pressure gradient
quickly relaxes later today with offshore gusts ceasing by midnight.
Onshore flow resumes by Tuesday afternoon. Temperatures today should
reach the mid 70s for most locations beyond 10 miles inland due to
the offshore winds. The marine layer has also been completely pushed
out today, but could low marine clouds/fog sneak into portions of
southern coastal San Diego County Tuesday morning. With onshore flow
resuming tomorrow and ahead of the next trough coming Tuesday night,
the marine layer deepens, likely stretching well into inland valleys
come Wednesday morning. High temperatures cool a few degrees for
Tuesday afternoon as well.

The trend away from light precipitation in favor of a dry offshore
wind event is now complete, with less than a 5% chance of
precipitation. If anything, the deeper marine layer will be what
ends up providing any moisture to the coasts/valleys Wednesday
morning. With fairly high confidence in another inside slider
Tuesday into Wednesday, offshore Santa Ana winds are expected to
pick up again Wednesday, likely persisting through Friday. The track
of this trough follows a very similar track to the one earlier in
the week and wind strength will be similar to today`s event as a
result. Winds peak late Wednesday into Thursday with gusts of 30-50
mph in mountain passes and 20-30 mph within downstream corridors of
inland valleys. Weak offshore flow continues into Friday morning
with the return of onshore flow by Friday afternoon. Temperatures
continue to gradually warm Wednesday through the weekend with the
persistent offshore flow giving way to weak upper ridging building
this weekend.


&&

.AVIATION...
012100Z....Coasts/Valleys...Offshore northeast winds 20-30kts with
locally higher gusts will continue in the foothills and inland
valleys through 02z Tue. Very patchy low clouds based around 1200-
1500 feet MSL will develop offshore after 06z, pushing into coastal
areas on Tuesday. There is a 30% of a brief CIG at KSAN and 20%
chance at KSNA, mostly after 11z. Otherwise, mostly clear and VFR
conditions will prevail tonight and tomorrow.

.Mountains/Deserts...VFR conditions through the period. Gusty
northeast surface winds on the coastal slopes of the mountains today
exceeding 35kts at times. Mod up/down drafts possible in the
vicinity of the mountain peaks. Localized areas of BLDU possible.
Winds diminish after 06z Tue.

&&

.MARINE...
No hazardous marine conditions are expected today through Friday.

&&

.BEACHES...
Astronomical high tides are forecast during the mornings Wednesday
through Friday, threatening minor tidal overflow and beach erosion.
Chances of these impacts are higher Wednesday and Thursday mornings
as elevated surf of 4-6 feet and a period of 16 seconds combines
with the high tides, especially for San Diego County.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement from Tuesday evening through Friday
     morning for Orange County Coastal Areas-San Diego County
     Coastal Areas.

PZ...None.

&&

$$

PUBLIC...Munyan
AVIATION/MARINE/BEACHES...Zuber