472
FXUS66 KSGX 292142
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
142 PM PST Sat Nov 29 2025

.SYNOPSIS...
Cooler and dry this weekend. Patchy fog along the coastal areas
and coastal mesas tonight. Weak to locally moderate Santa Ana
winds develop Monday and weaken Tuesday with warmer and drier
weather. 20-35% chance of light precipitation Wednesday into
Thursday, though confidence remains very low. Another round of
offshore winds like follow this system for the late week.

&&

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

Today through Monday...

In response to a shortwave trough now swinging through the Great
Plains, a 1026mb surface high in Nevada is contributing to a weak
offshore gradient, with north/easterly winds only felt in the
deserts to the mountain passes. Elsewhere, onshore flow prevails
though a meager coastal eddy this morning failed to reestablish
marine clouds, providing another cool morning across the coastal
basin. Aside from some high clouds, mostly sunny skies today warms
temperatures up to seasonable norms for late November.

The next shortwave trough is set to dig from the Pac NW through the
Great Basin tonight into Sunday, bringing elevated onshore winds
Sunday afternoon, mainly for the higher elevations in the mountains
and adjacent desert slopes. Wind gusts near 25-35 mph expected in
the high deserts/desert slopes with upwards of 35-45 mph near
mountain peaks. The marine layer will likely be less patchy tonight,
with cloud cover stretching into portions of the western inland
valleys. As cold air spills into the Great Basin behind this upper
trough, the offshore pressure gradient is expected to strengthen on
Monday, more than what is seen today. This Santa Ana wind event
looks to be weak to moderate strength with strongest wind gusts
Monday afternoon found in and just below Cajon/Banning Pass and
Fremont Canyon up to 45-50 mph, with 25-35 mph gusts spreading into
the Inland Empire and inland Valleys of San Diego and Orange
Counties. As for temperatures, Sunday will likely be a few degrees
cooler than today with the onshore flow, followed by warming and
drying on Monday with the offshore flow.

Tuesday into Late Week...

Onshore flow is quickly reestablished Tuesday afternoon, moderating
temperatures back to average. Beyond Tuesday, the upper level
pattern remains quite uncertain through mid-late week as models
continue to disagree on the evolution of the next trough, set to dig
southward on Wednesday. The GFS and its ensembles have a weaker,
shallower, and faster trough, while the ECMWF and its ensembles
feature a deeper and slower system. While this disagreement
persists, confidence on any precipitation, both timing and amounts,
will be low. In a scenario like the GFS`s, precipitation amounts
will be very low, likely 0.1" or less, with northerly offshore flow
building Wednesday into Thursday. If the ECMWF`s solution were to
verify, precipitation amounts could be closer to 0.25-0.5+" with
rain chances stretching into Thursday, delaying northerly offshore
flow into late Thursday into Friday. Uncertainty in snow levels
exists as well, but will generally be falling to around
6500-6000ft Wed-Thurs. Either way, this storm system isn`t
expected to be an efficient rain maker, but stay tuned over the
next few days to see how this evolves. Still, temperatures are
likely to cool below average Wed-Thurs with the trough/cloud
cover, though with the potential for offshore flow, its a bit too
early to say for sure.

&&

.AVIATION...
292030Z....Coasts/Valleys...Very patchy low clouds with bases around
400-700ft MSL will develop and move ashore after 02Z Sunday with VIS
down to 1-4SM. VIS may fall to 1/2SM or lower earlier in the night
for obscured coastal terrain. A weak eddy may allow bases to rise a
bit, possibly to around 600-1200ft MSL by 10-13z. Clouds will begin
to clear back towards the coast by 15-16z.

.Mountains/Deserts...VFR conditions expected through the TAF
period. Strong surface winds exceeding 30 mph at times possible in
the deserts and eastern mountain slopes generally after 16z Sunday.
Mod up/downdrafts expected in the vicinity of the mountains and for
any low-flying aircraft.

&&

.MARINE...
No hazardous marine conditions are expected through Thursday.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.

&&

$$

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