050
FXUS66 KSGX 201534
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
834 AM PDT Thu Jun 20 2024

.SYNOPSIS...
A warming trend will continue through Saturday with high
temperatures on Saturday as much as 5 to 10 degrees above average.
A shallow intrusion of lower level moisture for the lower deserts
will bring warmer nights with days not quite as hot for the
weekend. There is also a slight chance of showers and
thunderstorms, mainly for the mountains and deserts, for Saturday
afternoon and again on Sunday. Then a little drier and continued
hot inland for Monday through Wednesday. The marine layer will
continue to keep areas near the coast cooler. Night and morning
coastal low clouds will continue to spread into portions of the
valleys late each night but less extensive coverage.

&&

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

Marine layer is shallower this morning with a top around 2200 feet
MSL so it extends only into parts of Riverside but most of the
Inland Empire is sunny. In San Diego county it follows along but
just east of I-15 for inland extension. We should see good burn
off in normal fashion this morning. The upper level heights rise
on Friday so the marine layer will squash further but persist and
become less organized  in coverage and only weak eddy formation.

The heat wave still on track with warming Friday and Saturday for
all areas. The moisture surge starts Saturday and continues into
Sunday. The instability is very marginal and mostly in the
Colorado River valley for Saturday but enters into San Diego
mountains as well. This expands on Sunday with moderate
instability due to the moisture increase across our mountains.
The 850 mb temperatures peak at 32C in the lower deserts under 594
DM 500 mb heights so this looks to be the warmest of season and
also prolonged before the upper ridge weakens slightly late next
week.


.AVIATION...
201525Z...Coast/Valleys...Areas of low clouds with bases
1300-1500 ft MSL and tops to 2000 ft MSL will continue to spread
around 20-25 miles this morning. Local VIS 3-5 SM in BR/FG where
clouds near terrain in the valleys, including VCNTY KRNM. Valleys
clearing 14Z-16Z, with coastal areas clearing 16Z-19Z. Areas of
low clouds will develop again this evening with bases around
700-1000 ft MSL and tops to 1500 ft MSL, spreading 10-15 mi inland
tonight into Fri morning.

Mountains/Deserts...Mostly clear with unrestricted VIS will continue
through Thu evening. West winds with gusts 20-30 kt through San
Gorgonio Pass and on the desert slopes this afternoon and evening.

&&

.MARINE...
No hazardous marine weather conditions are expected through
Monday.

&&

.FIRE WEATHER...
Fuels have dried to normal levels over inland areas where
temperatures have been running above normal past 2 months.

&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory from 10 AM Saturday to 8 PM PDT Sunday for Orange
     County Inland Areas-San Bernardino and Riverside County
     Valleys-The Inland Empire.

 Heat Advisory from 1&&0 AM to 8 PM PDT Saturday for Riverside
County Mountains-San Bernardino County Mountains-San Diego County
Mountains-San Diego County Valleys.

     Excessive Heat Watch from Tuesday morning through Wednesday
     evening for Coachella Valley.

     Excessive Heat Watch from Saturday morning through Thursday
     evening for San Diego County Deserts.

PZ...None.

&&

$$

PUBLIC/FIRE WEATHER...Tardy
AVIATION/MARINE...Small