851
FXUS66 KSGX 240429
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
929 PM PDT Mon Sep 23 2024

.SYNOPSIS...
Slightly above average temperatures are expected for inland areas on
Tuesday. A few degrees of cooling is expected for Wednesday and
Thursday. Friday may be a little warmer, followed by slow cooling
for next weekend with increasing uncertainty in the high temperature
forecast for the weekend. Night and morning coastal low clouds and
fog will spread into portions of the western valleys late each
night.

&&

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

Visible satellite at 9 PM was showing areas of low clouds along the
Orange and San Diego County coastlines and into San Diego county`s
western valleys. Areas of fog are expected near higher coastal
terrain and in western portions of the valleys into Tuesday morning.
There is a 30 to 50 percent chance of visibility one mile or less
along portions of the I-15 corridor in San Diego County and along
I-5 in southern Orange County during the early morning commute.
Highs on Tuesday compared to today are expected to be similar to a
degree cooler for areas west of the mountains and similar to a
degree or two warmer for the mountains and deserts.

From previous discussion issued at 2 PM Monday September 23...

A weak low pressure system off the California coast may bring a few
degrees of cooling for Wednesday and Thursday as the upper high gets
displaced eastward into the Great Basin.

That weak low pressure system may move farther off the California
coast on Friday allowing the upper high to expand westward, with
high temperatures slightly warmer. For next weekend, that weak low
pressure system may move back towards Southern California with
differences in model placement and timing. The deterministic NBM has
slight cooling for Saturday and Sunday, but with increasing spread
in the high temperature guidance

&&

.AVIATION...
240330Z...Coasts/Valleys...Low marine stratus (based around 600-
900ft MSL, tops near 1500ft MSL) have pushed about 10-15 miles
inland in San Diego County and are now starting to gradually move
into coastal Orange County at this hour. Bases could fall another
hundred feet or so by 12z with visibility falling to 3-6 miles along
the coasts, and less than 3 miles where clouds intersect inland
terrain. There is a low chance (20-30%) that CIGs sneak into the
western Inland Empire and KONT, but this is quite unlikely. Clouds
look to clear along the coasts around 17-18z, lingering just
offshore through the afternoon before pushing back inland after 00z
Wednesday.

Mountains/Deserts...Mostly clear skies with unrestricted VIS
expected through Sunday evening.

&&

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

&&

.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/PG
AVIATION/MARINE...Munyan