FXUS66 KSGX 251635
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
935 AM PDT Sun Aug 25 2024

.SYNOPSIS...
A gradual warming trend is expected through Tuesday. For the middle
to end of the week, temperatures will fluctuate a few degrees each
day. Night and morning low clouds and patchy fog will develop near
the coast. Monsoonal moisture may make a return for the latter half
of the week, but thunderstorm probabilities remain below 15
percent.

&&

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

Visible satellite at 9 AM was showing mostly clear skies across the
area with a few patches of low clouds over the coastal waters. Highs
today are expected to be 3 to 7 degrees warmer for areas west of the
mountains, with temperatures expected to be similar to a degree or
two cooler than yesterday in the deserts. The marine layer is
expected to get shallower with weak high pressure aloft early this
week. That will keep low cloud and fog coverage mostly confined
to coastal areas, locally into the western valleys.

High temperatures are expected to continue to warm into Tuesday as a
weak ridge of high pressure moves over California. By Tuesday, high
temperatures will be near to a few degrees above normal for this
time of year. An upper low passing through the Pac NW and a
secondary weak low developing off the CA coast will bring minor
cooling on Wednesday. This weak west-to-east trough axis remains
somewhere in the vicinity of Southern California through at least
Friday, undercutting the ridge to our north and east. This maintains
near normal temperatures for Wednesday through next weekend.

How the upper level pattern sets up will play a big role in if any
monsoonal moisture makes a return to Southern California. Ensembles
are still showing quite a bit of spread in precipitable water.
Both the ECMWF and GFS ensemble have 20-40 percent chance of
precipitable water greater than 1" late Thursday into Friday,
with much higher probabilities towards the Colorado River Valley.
Instability is also quite limited over the mountains, so have kept
shower/thunderstorm chances below 15 percent for now.

&&

.AVIATION...

251600Z...Coast/Valleys...No significant low clouds are expected
during the daylight hours today. Chances are higher for low ceilings
returning to coastal sites tonight, possibly as early as 06z Monday.
Localized VIS restrictions of 4-6SM possible for higher coastal
terrain and valleys as early as 04z Monday.

Mountains/Deserts...Unrestricted VIS and mostly clear skies expected
to prevail through through Monday morning.

&&

.MARINE...

No hazardous marine conditions are expected through Thursday.

&&

.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...Suk