898
FXUS66 KSGX 282105
AFDSGX

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

.SYNOPSIS...
Hot weather will increase inland this weekend while coastal low
clouds will be less extensive. It will continue very hot inland
for the entire coming week, especially in the deserts. The
shallower marine layer will modify temperatures near the coast.

&&

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

The eddy circulation has prevented some coastal areas from
completely clearing out today. The eddy will fade and mostly
sunny skies will prevail this afternoon. 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...
282000Z...Coast/Valleys...Lingering low clouds bases around 1400
feet MSL in southwest San Diego Co. have also built back into
beaches along northern San Diego and southern Orange Co. More
southerly flow than expected along southern coast has pushed marine
layer onshore this morning and afternoon and looks to continue to do
so. Low clouds return to remainder of coastal sites as they push
inland 01-04Z, with a similar bases and inland extent as last night.
Higher pressure aloft could result in slight lowering of cigs 29 10-
12Z, but not significantly. Localized vis below 3SM possible in
coastal valleys overnight. Low clouds clearing 16-18Z.

Mountains/Deserts...FEW clouds at or abv 10,000 ft MSL possible this
afternoon, dissipating by sunset. Otherwise mostly clear with
unrestricted VIS through this evening.

Northwest winds gusting to 45 mph in the wind-prone passes and
canyons again this afternoon with moderate up/downdrafts over and
east of the mtns. Slight reduction in afternoon/evening winds Sat.

&&

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

&&

.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...MM
AVIATION/MARINE...CSP