615
FXUS66 KSGX 020538
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
938 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...

No significant changes to the forecast this evening under a
relaxing offshore wind regime. Will continue to monitor for
radiational fog formation across the area ahead of a return to
onshore flow.

Previous discussion from December 1st at 13:42 PST

.SHORT TERM...
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...
020400Z....Coasts/Valleys...Offshore northeast winds locally gusting
to 20-30 kts in coastal foothills and inland valleys will continue
to calm overnight. Currently clear skies, with a 20-30% chance for
low clouds to develop and intermittently impact coastal sites
(KSAN/KSNA) early Tues morning, generally 07-15Z. If low clouds do
develop locally, vis and cigs will likely be very low, with a chance
for dense fog vis 0-2 SM and bases 100-300 ft MSL. Widespread if
patchy low clouds will return after 02Z Wed. Bases could start out
fairly low 800-1500 ft MSL but will rise overnight to 1800-2500 ft
MSL.

.Mountains/Deserts...VFR conditions through the period. Locally
gusty northeast surface winds 20-35 kts on the coastal slopes of the
mountains through about 06Z, diminishing afterwards. Mod up/down
drafts possible in the vicinity of the mountain peaks.

&&

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

&&

.BEACHES...
Astronomical high tides are forecast to occur each morning 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 combines with the high tides,
especially for San Diego County.

&&

.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.


&&

.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...Suk
AVIATION/MARINE/BEACHES...CSP