616
FXUS66 KSGX 290422
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
922 PM PDT Fri Jun 28 2024

.SYNOPSIS...
A prolonged period of heat is expected for inland areas this weekend
into next week. The hottest locations will be in the deserts. The
marine layer is expected each night and morning near the coast into
early next week.

&&

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

At 9 PM satellite imagery was showing marine layer low clouds and
fog starting to make its way into Orange County, but still offshore
along the San Diego coast. Low clouds are expected to eventually
make it to the coast, locally into the western valleys overnight.
High temperatures on Saturday are expected to be a few degrees
warmer than today for areas west of the mountains and in the High
Desert. Further warming is expected into Sunday, with widespread
above average temperatures.

From previous discussion issued at 2 PM June 28, 2024...

High pressure aloft will dominate the weather picture over the West
for the foreseeable future. This will mean very hot weather in the
deserts and to a lesser extent in the inland valleys. A weak trough
to our northwest and a big ridge to our east will jockey for
position over SoCal this entire coming week. The ridge will gain the
upper hand and bring the hot weather. An Excessive Heat Watch is now
in effect for all desert regions, where temps will rise to about 113-
116 in the lower desert, up to 106-109 in the high desert. Only a
couple degrees of "cooling" can be expected Monday through Thursday,
but good agreement in models and ensembles are showing another, more
significant, high pressure ridge toward next weekend. It is very
strong (600 DM) and centered over NorCal and NV, especially next
Friday and beyond. Right now it appears temps next Friday and
Saturday will exceed temps this weekend and we should break some
daily max temp and min temp records, too. Meanwhile, back at the
coast, the marine layer will get squashed and disrupted by the
higher pressure aloft, so low clouds will become lest extensive and
less uniform in coverage each night and morning. Temperatures inland
appear 4-10 degrees above average on Sunday and Friday, the hottest
days in the coming week. It could be even hotter inland the
following weekend.

&&

.AVIATION...
290430Z...Coast/Valleys...Areas of low clouds will gradually develop
along the coast through 08Z and then spread up to 20 miles inland by
12Z Sat. BKN/OVC bases will mostly be 1300-1800 ft MSL with tops to
2100 ft MSL. Some coastal airports will be TEMPO SCT at times. Local
VIS 2-4 miles will occur higher coastal terrain in BR 09Z-16Z Sat.
Most areas will clear 15Z-18Z Sat except for local lingering low
clouds at the beaches through Sat afternoon. Low clouds will be slow
to develop Sat evening.

Mountains/Deserts...Mostly clear skies with unrestricted VIS will
continue through Sat evening. Local gusts 25-35 kt from the west
will occur on the desert slopes and adjacent deserts and through San
Gorgonio Pass through 09Z Sat.

&&

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

&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Excessive Heat Watch from Sunday morning through Friday evening
     for Apple and Lucerne Valleys-Coachella Valley-San Diego
     County Deserts-San Gorgonio Pass Near Banning.

PZ...None.

&&

$$

PUBLIC...CO/MM
AVIATION/MARINE...Maxwell