032
FXUS66 KSGX 132042
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
142 PM PDT Wed Aug 13 2025

.SYNOPSIS...
Fair and slightly cooler weather is expected today through
the weekend as a low pressure trough hangs over the West. The
marine layer will send coastal clouds into parts of inland valleys
each night and morning. Temperatures will remain a little below
normal. Next week, high pressure rebuilds over the Southwest,
which will bring a modest warming trend to Southern California,
with temperatures returning to around average.

&&

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

As we suspected, coastal clouds have struggled and failed to fully
clear from the coast so far today. The strong marine inversion and
the coastal eddy are doing their job of juicing the marine layer. A
weak but deepening trough of low pressure over the Pac NW and our
local coastal eddy have contributed to this deeper marine layer
trend. This trough will drive our general cool pattern through
the weekend, with cooler weather in all areas and low clouds and
fog reaching into parts of the inland valleys each night and
morning. Temperatures will continue a few degrees below normal
west of the mountains through Thursday, while temps continue a few
degrees above average in the mountains and deserts. That is
especially true today as we head into the final hours of our
Extreme Heat Warning for our lower deserts. A cooler air mass
Friday and Saturday will bring the entire region below average
those days and through the weekend at least. Next week we`re
fairly confident that the high pressure ridge over the Southwest
will strengthen and expand into SoCal, eventually centering over
the four corners area. This will bring a warming trend for all
areas and of course a shallowing of the marine layer. That will
mean less extensive coastal cloudiness and less duration next
week. It won`t be a rapid or significant warming trend, as
temperatures will take a few days to get back to average, maybe
not until Wednesday. For the past monthor so we`ve been teased by
model guidance showing some increase in monsoon moisture about a
week into the future. But we`re not offended by the bullying
tease, so we have no meaningful chances of precipitation in our
forecast. There are some hints late next week that the ridge will
weaken slightly, hinting at a cooling trend.

&&

.AVIATION...
132000Z...Coasts/Valleys...Low clouds based at 1000-1500 ft MSL are
lingering along the immediate coast, locally at KSAN and KCRQ. SCT
conditions could return to KSAN and KCRQ through 00Z Thu, before BKN-
OVC cigs begin to prevail and move further inland. VFR conditions
continue to prevail this afternoon for the valleys. BKN-OVC bases
are expected to be 700-1400 ft MSL overnight, with vis restrictions
3-5SM in BR near higher coastal terrain and locally in the valleys.
There is a 40 percent chance of clouds with cigs around 800 ft MSL
reaching KONT 10-14Z Thu. SCT conditions expected 17-19Z Thu, with
partial and interment clearing expected along the immediate coast.

Mountains/Deserts...Mostly clear with VFR conditions through
Thu.

&&

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

&&

.BEACHES...
A 14-16 second southwesterly (200-220 degree) swell will bring
elevated surf and a high rip current risk to southwest facing
beaches. Surf of 3 to 5 feet, with sets to 6 feet, are expected
through Thursday, with surf lowering 2 to 4 feet by Friday. Strong rip
currents could continue into Friday for some beaches. Consult
a local lifeguard if you`re at the beach.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Extreme Heat Warning until 8 PM PDT this evening for Coachella
     Valley-San Diego County Deserts-San Gorgonio Pass near
     Banning.

PZ...None.

&&

$$

PUBLIC...MM
AVIATION/MARINE/BEACHES...CO