Area Forecast Discussion
Issued by NWS San Diego, CA

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653
FXUS66 KSGX 121626
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
926 AM PDT Wed Jun 12 2024

.SYNOPSIS...
Marine layer night and morning low clouds and fog will persist along
the coast, into the valleys at times, each day into next week. A few
degrees of warming is expected for the coast and valleys today, with
widespread cooling Thursday. Another bout of warming is expected for
Friday and Saturday, most noticeable in the lower deserts. Cooler
conditions will return Sunday through the middle of next week.
Periods of gusty southwest to west winds are expected in the
mountains and deserts each afternoon and evening into next week.

&&

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

Visible satellite this morning showed low clouds had filled in most
of the coastal basin overnight. As of 9 AM, clouds are slowly
beginning to clear the valleys. Low clouds are expected to linger at
some beaches this afternoon. With better clearing west of the
mountains today, coast and valley locations are expected to be 5 to
12 degrees warmer than yesterday. In and east of the mountains,
highs will be a mix of a few degrees warmer and a few degrees cooler
than yesterday. The mountains and High Deserts are the places likely
to experience temperatures a few degrees cooler than yesterday.

A weak low pressure system will move inland through southern
California late Thursday. As a result, high temperatures on Thursday
will be a few degrees cooler than today for most areas from the
coast to the deserts. The cooling trend will be brief as a weak high
pressure system sets up over southeastern California, southern
Nevada, and western Arizona Friday and Saturday. For Friday, highs
will be a degree or two warmer for the coast; 2-4 degrees warmer for
the valleys; 4-8 degrees warmer for the mountains, the Apple and
Lucerne Valleys, and the low deserts. Warming will continue into
Saturday, which will be the peak of this brief warming trend. Highs
are expected to be 3-5 degrees above average for the coast and
western valleys and 5-10 degrees above average for portions of the
eastern valleys, mountains, and deserts. Moderate to locally major
heat risk is expected in the low deserts, with ares of moderate heat
risk in the Inland Empire, mountains, and High Desert.

A low pressure system moves inland through the western states Sunday
into the middle of next week, bringing cooler conditions to the
area. The deserts may experience a few degrees of cooling each day
through Tuesday while the coast into the valleys may begin to slowly
warm by Tuesday. The increase in onshore flow with the passing
trough will also allow for the marine layer to deepen again with low
clouds reaching into the valleys.

&&

.AVIATION...
121545Z...Coast/Valleys...Low clouds based 900-1100 ft MSL with
tops to 2500 ft MSL. Coastal airports expected to clear today
as the low clouds should clear back to over the coastal water.

After 13/0300 UTC this afternoon low clouds based 900-1100 ft
MSL with spreading inland, reaching KONT around 10Z but
unlikely to reach KSBD. Areas of VIS 2-4SM in fog where
clouds and terrain intersect. Confidence in SCT conditions
at KSAN mid-afternoon today is moderate.

Mountains/Deserts...SKC with unrestricted VIS through today.

&&

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

&&

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


&&

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

&&

$$

PUBLIC...CO
AVIATION/MARINE...Small