Excessive Heat Warning 2, NWS San Diego, CA

Area Forecast Discussion
National Weather Service San Diego CA
241 AM PDT Mon Jun 11 2018

.SYNOPSIS...
Subtropical high pressure will expand westward into Southern
California bringing an inland warming trend through Wednesday. A
trough of low pressure developing over the western states will
bring a cooling trend for Thursday through next weekend. The
marine layer and weak onshore flow will keep coastal areas cooler
with areas of night and morning low clouds and fog extending
locally inland. That trough of low pressure could draw some
tropical moisture northward with a slight chance of afternoon
thunderstorms near the mountains around Friday.

&&

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

.SHORT TERM (Today through Wednesday)...
Subtropical high pressure aloft centered over New Mexico and
northern Mexico combined with weaker onshore flow will bring a
warming trend through Wednesday. Tuesday and Wednesday will be
similarly warm for many locations with high temperatures for
inland areas 5 to 10 degrees above average. Areas of night and
morning low clouds and fog across the coastal waters will spread
locally inland into coastal areas.

&&

.LONG TERM (Thursday through Sunday)...
The models develop a trough of low pressure over the western
states with the bulk of the global models maintaining onshore
lower level flow and dry southwest to west flow aloft across
Southern California. The ECMWF is weaker and a little farther west
with the troughing in the vicinity of Southern California with the
potential to draw some mid level moisture northward across the
area Thursday and Friday. There could be some mid clouds around
Thursday and small chances for elevated convection for Friday
afternoon and evening.

The trough of low pressure and onshore flow will bring a cooling
trend for Thursday through next weekend. Areas of night and
morning coastal low clouds and fog will spread locally inland.
Depending on the placement and strength of the trough...some
deepening of the marine layer is possible for next weekend as
well.

&&

.AVIATION...
110900Z...Coast...Areas of low clouds are expected this
morning, with intermittent cigs at some coastal airports. If/when
cigs develop, bases will be close to 600-800 feet msl and vis
locally reduced on higher coastal terrain. After 16Z skies will be
mostly clear. A similar pattern returns tonight after 05Z with low
confidence on the time and location of cigs overnight.

Valleys/Mountains/Deserts...Mostly clear with unrestricted VIS today
and tonight.

&&

.MARINE...
No hazardous marine weather is forecast through Friday.

&&

.BEACHES...
Swells from the southern hemisphere will bring high surf to the
beaches today through Tuesday. The swell and surf will gradually
subside late Tuesday and Wednesday. Check the High Surf Advisory and
the Surf Zone Forecast for the details.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory until 8 PM PDT Tuesday for Orange County
     Coastal Areas-San Diego County Coastal Areas.

PZ...NONE.

&&

PUBLIC...17
AVIATION/MARINE/BEACHES...MM