220
FXUS66 KSGX 231050
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
350 AM PDT Fri Jun 23 2017

.SYNOPSIS...
Strong high pressure will continue to bring hot weather to the
Southern California interior while the marine layer will dominate
near the coast. There is a slight warming trend and less
extensive coastal cloudiness for the weekend. A very welcome but
gradual cooling trend will develop for much next week.

&&

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

The marine layer has deepened quite a bit and low clouds are well
into the valleys this morning. Drizzle could occur this morning
near the coast and mesas but no reports noted attm. Temps today
will be similar to yesterday, a couple degrees warmer in the
deserts as the ridge becomes a little better oriented and slight
westward shift, and perhaps a few degrees lower west of the mtns
due to the deeper marine layer.

Weak mid level moist S flow around the high will bring some thin
moisture into Southern California through today with a few Cu
buildups likely over the mountains but not enough of the prime
ingredients to generate showers or storms.

For this weekend the ridge strengthens a bit and will bring a
warmup for well inland, mountain, and desert locations. The
hottest temperatures are still slated for Sunday when the lower
deserts could touch 120 degrees again. Western valleys and the
coast will continue to be influenced by the marine layer although
it should become a bit shallower due to the decreasing onshore
component.

For next week, the ridge will gradually weaken, with some break in
the heat wave finally for the deserts. Tuesday through Wednesday
we`re actually along the southernmost flank of an area of
increased zonal flow which should bring the greatest cooling along
with some periods of gusty winds. Temperatures will settle to
near normal to slightly above normal for the remainder of next
week. Medium range models are starting to hint at some rebuilding
of the 4 Corners high by next weekend which would bring another
warmup for inland areas.

&&

.AVIATION...
230400Z...Coast/Valleys...Stratus with bases 900-1500 ft MSL
continuing over coastal areas and into the western valleys through
the morning. Local vis 3-5 SM where stratus nears higher terrain in
the valleys. Slow clearing in the valleys 16-19Z, with little to no
clearing along the immediate coast. KSAN and KCRQ may have a brief
period of FEW-SCT clouds mainly 21-00Z. Stratus will spread inland
again after 24/00Z with bases mostly 800-1200 ft MSL.

Mountains/Deserts...Increasing clouds in the 15000-20000 ft MSL
layer through the day. SCT Cu may develop over the mountains during
the afternoon, dissipating by sunset. VIS remaining unrestricted.

&&

.MARINE...
Northwest wind gusts over the outer waters may reach 25 kt during
the afternoons and evenings from Sunday through Tuesday, potentially
resulting in conditions hazardous to small craft.


&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Excessive Heat Warning until 9 PM PDT Monday for Coachella
     Valley-San Diego County Deserts-San Gorgonio Pass Near
     Banning.

     Heat Advisory from 10 AM to 9 PM PDT Sunday for Riverside County
     Mountains-San Bernardino County Mountains-San Bernardino
     and Riverside County Valleys-The Inland Empire-San Diego
     County Mountains-San Diego County Valleys-Santa Ana
     Mountains and Foothills.

     Excessive Heat Warning until 9 PM PDT Sunday for Apple and
     Lucerne Valleys.

PZ...NONE.
&&

$$

PUBLIC...Brotherton
AVIATION/MARINE...SS