DesertWeather.com

194
FXUS66 KSGX 290931
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
231 AM PDT Sat Aug 29 2026

.SYNOPSIS...
Above average high and low temperatures will continue today,
falling to around normal by Sunday. The cooling trend continues
through the middle of next week. For Tuesday and Wednesday,
increased high cloud cover is likely along with a 15 to 25
percent chance of light precipitation as moisture from Tropical
Storm Karina potentially gets pulled northward. This tropical
system is forecast to remain well to our south.

&&

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


...UPDATED AVIATION DISCUSSION...

Patchy low clouds have developed along the coast again this
morning with just a few high clouds elsewhere. Low clouds and
patchy fog are forecast to spread northward along the coast and a
few miles inland through sunrise, clearing by mid-morning. Today
will be the last day of the heat wave with temperatures a few
degrees lower than yesterday. Highs will generally be in the low
to mid 80s at the coast to the low 90s to low 100s for the inland
coastal areas and valleys, mid 80s to mid 90s in the lower
elevation mountains, mid 70s to mid 80s for the higher elevation
mountains, mid to upper 90s in the high desert, and 105 to 112 in
the low deserts. Monsoon moisture decreases today as flow aloft
turns more southwesterly and precipitation chances this
afternoon are less than 5%.

For Sunday through Wednesday, the upper level high which brought
the relentless heat retreats to the Southeast US as upper level
troughing develops along the West Coast. This pattern change
will bring gradual cooling to So Cal. By Sunday, highs will
finally return to late-August normals, falling to as much as 5 to
10 degrees below normal by Wednesday. This drier flow pattern will
also offer some reprieve from the humidity and better cooling at
night. Say goodbye to dew points in the 70s (for now). For Tuesday
and Wednesday, there is still the potential from mid and upper
level moisture from Tropical Storm Karina (which is forecast to
become a hurricane later today), to be pulled northward into
California. The storm itself is forecast to remain well to our
south. Global ensembles still disagree greatly with respect to
the amount of moisture that moves into our area. Some members of
the GEFS and Canadian have Precipitable Water in excess of 2" and
ensemble means near 1.5", while the EC ensemble is significantly
drier due to differences in the track of the tropical system. Even
with the increase in moisture, forcing will be weak, so if we do
manage to get any precipitation it will most likely be light. For
now PoPs remain around 15-25% for late Tuesday and Wednesday.
Otherwise during this period expect the marine layer to rebuild
and deepen, allowing low clouds and fog to spread slightly further
into the coastal areas and far western valleys during the nights
and mornings.

Thursday into next weekend, the upper level high begins to shift
back westward, bringing warming and the potential return of
monsoon moisture. High temperatures return to near average by
Friday.

&&

.AVIATION...
290930Z...Coast...Low clouds based 400-700 ft MSL have become more
widespread along the San Diego Co coastline and inland to about 10
miles, with vis 2-5 SM over higher coastal terrain. Clouds will
creep into parts of southern OC, with ~30% chance for impacts vcnty
KSNA through 15Z this morning. More widespread low clouds 600-1000
ft MSL will form after 06Z Sun, with impacts to coastal sites likely
by 09Z.

Regionwide...Mostly clear skies except for periods FEW upper lvl
clouds AOA 15kft.

&&

.MARINE...
Gusts around 20 knots expected this afternoon in the vicinity of San
Clemete Island. Otherwise, no hazardous marine conditions are
expected through Wednesday.

&&

.BEACHES...
A 3-foot swell from the south-southwest (200 degrees) at 15-17
seconds moves into the region today and Sunday. This will bring
localized elevated surf of 3-5 feet with sets to 6 feet, along with
a high rip current risk to southwest-facing beaches, mostly in north
San Diego County and Orange County.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory until 8 PM PDT this evening for Orange County
     Coastal Areas-San Diego County Coastal Areas.

     Extreme Heat Warning until 8 PM PDT this evening for Coachella
     Valley-Orange County Inland Areas-San Bernardino and
     Riverside County Valleys-The Inland Empire-San Diego County
     Deserts-San Diego County Mountains-San Diego County Valleys-
     San Gorgonio Pass near Banning-Santa Ana Mountains and
     Foothills.

PZ...None.

&&

$$

PUBLIC...SS
AVIATION/MARINE/BEACHES...CSP