Blue Jay, California Weather Forecast Discussion

166
FXUS66 KSGX 302024
AFDSGX
Area Forecast Discussion
National Weather Service San Diego CA
124 PM PDT Tue Sep 30 2025
.SYNOPSIS...
A low pressure trough moving inland along the West Coast will
bring cooling today, with a deeper marine layer. This will be
followed by warming for Wednesday and Thursday, but with high
temperatures remaining below average. Another low pressure system
will move inland through California on Friday with cooling of a
few to around 5 degrees and slight additional cooling for inland
areas on Saturday. Then mostly slight day to day differences for
Sunday and Monday with high temperatures remaining at least a few
degrees below average.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
Mostly clear this afternoon except for a few low clouds in the San
Diego County coastal areas. As the upper trough moves inland tonight,
the marine layer may become marginally shallower but when the low
clouds develop tonight they will likely spread inland to the
coastal mtn slopes once again. Inland temperatures are mostly a
few degrees cooler than at this time yesterday except for the San
Diego County deserts where temps are a few degrees warmer.
From previous discussion...
For Wednesday and Thursday, the low pressure trough will move
inland and weaken. High pressure to the south will briefly
rebound, bringing warmer conditions with the marine layer
becoming a little shallower. High temperatures will warm a few
degrees on Wednesday and a few more degrees on Thursday but high
temperatures will remain around 4-7 degrees below average. High
temperatures on Thursday will range from the lower 70s near the
coast to the lower to mid 80s for the Inland Empire and the low
to mid 90s for the lower deserts.
For Friday into early next week...A low pressure system from the
Gulf of Alaska will move into CA with a closed upper low over
northern/central CA by Friday morning. The closed low will move
east and become an open wave by Sunday. This will bring general
cooling with temperatures about 5 degrees lower on Fri and further
cooling for Sat. Current indications are that Monday will be the
coolest day with temperatures as much as 10-12 degrees below
seasonal averages in the inland valleys. This system will also
bring a deeper marine layer and stronger onshore flow. Gusty
westerly winds will be likely for Friday into Saturday, mainly in
the mtns and adjacent desert areas. We will remain under the
influence of low pressure troughing through early next week,
although the forecast details will be less certain after Sat as
model solutions begin to diverge significantly.
&&
.AVIATION...
302000Z....Coasts/Valleys...Mostly clear skies and VFR this
afternoon. Low clouds based 1200-2000 ft MSL to redevelop after 04Z
this evening, spreading through the coastal basin, but in patchy,
random, and intermittent fashion. 60-70% chance coastal TAF sites
KSAN and KCRQ remain free of consistent cigs, though periods of off-
and-on cigs are still possible. KSNA has a better chance at
developing cigs, after 09z. Scatter out everywhere between 15-17z.
Mountains/Deserts...Mostly clear and VFR conditions through Tuesday.
&&
.MARINE...
No hazardous marine conditions are expected through Saturday.
&&
.BEACHES...
South swell will continue to produce elevated surf and a high rip
current risk through this evening. Surf of 3-6 feet with sets 7 feet
expected on south facing beaches. Strong longshore currents will
impact all beaches. Surf will slowly diminish today and tonight.
More information can be found in the Beach Hazards Statement.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement until 11 PM PDT this evening for Orange
     County Coastal Areas-San Diego County Coastal Areas.
PZ...None.
&&
$$
PUBLIC...PG
AVIATION/MARINE/BEACHES...Westerink

NWS SGX Office Area Forecast Discussion