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000 
FXUS66 KSGX 152027
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
127 PM PDT Wed Aug 15 2018

.SYNOPSIS...
Monsoonal moisture will increase through Thursday with increasing
chances for afternoon and early evening thunderstorms in the
mountains and deserts. High pressure aloft will move westward and
over Southern California for Friday through Sunday bringing drying
and a warming trend. Minor intrusions of monsoonal moisture may
return next week as high pressure moves back to the east. Areas 
of night and morning low clouds and fog will continue for coastal 
areas.

&&

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

Coastal low clouds cleared later today and not completely from San
Diego. Thunderstorms are getting going, starting over the 
mountain crests. A few of these could get nasty before the day is
done, but will stay mostly confined to the mountains. A little
more moisture Thursday in easterly flow will combine with the 
high instability already present to bring more thunderstorms to 
the mountains and deserts, and even could help a couple 
thunderstorms drift west of the mountains into inland valleys. 
The tenacious nature of the coastal clouds and model guidance
suggest the marine layer to be largely unfazed by this latest 
monsoon push, and maintains night and morning coastal clouds 
getting into westernmost valleys each night. The monsoon flow 
backs off on Friday for fewer thunderstorms in the mountains and
deserts. High pressure aloft strengthens a bit this weekend while
the monsoon flow backs off. That will mean higher temperatures 
and a shallower marine layer, but no thunderstorms. Next week 
models show some increase in monsoonal moisture, but not very 
convincing to forecast much chance of thunderstorms until Tuesday
and Wednesday. The high breaks down slightly as well, so it 
doesn't appear as hot but probably more humid. Overall, minor ebbs
and flows in monsoon flow, slight variations in marine layer and 
coastal cloud extent, and minor fluctuations in temperatures. In 
other words, seasonal summer weather.

&&

.AVIATION... 
151900Z...Coasts/Valleys...SCT-BKN15-020 near the coast this 
afternoon becoming OVC015-020 through 04Z and moving 20 miles inland 
through 16Z Thursday. From 16-21Z...gradual clearing back to the 
coast. 

Mountains/Deserts...Scattered TSRA over the mountains between 20-03Z 
with some storms moving into the upper deserts near Victorville and 
Barstow. Reduced vis in heavy rain, and gusty sfc winds 30-40 kt 
near storms.

&&

.MARINE...
No hazardous marine weather is expected through Sunday.

&&

.BEACHES...
Beach Hazard Statement through Friday for above average surf and 
strong rip currents. A southern hemisphere 180 degree, 4 ft swell at 
17 seconds will arrive this evening and bring elevated surf and 
strong rip currents tonight through Friday. The surf will peak 
Friday at 3-6 ft with sets to 8 ft on southwest facing beaches, then 
slowly subside Saturday and Sunday. 

The surf and swell will peak Friday, then slowly decrease Saturday 
and Sunday.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement from 9 PM PDT this evening through 
     Friday evening for Orange County Coastal Areas-San Diego 
     County Coastal Areas.

PZ...NONE.

&&

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