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000
FXUS66 KSGX 172038
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
138 PM PDT Fri Aug 17 2018

.SYNOPSIS...
Monsoonal moisture will bring some thunderstorms mainly to the
mountains this afternoon. Warmer and drier weather is expected
Saturday through Monday. For Tuesday and Wednesday, monsoon
moisture will increase, bringing a chance of afternoon
thunderstorms for the mountains and deserts. Coastal areas will
continue to get areas of night and morning low clouds.

&&

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

Several thunderstorms have erupted in the mountains and are
dropping locally heavy rain. They might cause some problems with
severe damage or flash flooding this afternoon. But they won`t be
as numerous or as widespread, or as evil, as they were yesterday,
although instability is still quite high so any individual storm
could grow pretty strong. Thunderstorms should dissipate fairly
rapidly after about 6 pm as monsoon moisture and instability
decrease. The atmosphere dries out a little more this weekend,
although we`ll see some cumulus clouds build over the mountains
each afternoon. With the higher pressure aloft, the coastal clouds
will be relegated to the coast and far western valleys each night
and morning. Temperatures will climb inland a few degrees this
weekend, and a few more Tuesday and Wednesday. When will the
thunderstorms return? Right now it appears to be Tuesday through
Thursday. Which day will have the most thunderstorms still eludes
us becauses guidance varies on that question. All next week look
for seasonal August weather with a shallow marine layer and
varying chances of mountain thunderstorms each afternoon.

&&

.AVIATION...
172000Z...Coasts/Valleys...BKN/OVC coastal stratus will begin to
spread back inland after 00Z this evening, with similar bases to
this morning, with bases 1300-1800 ft MSL and tops to 2200 ft MSL.
Stratus should clear to the coast 16-18Z Saturday morning, with some
clouds lingering at the beaches into Saturday afternoon.

Mountains/Deserts...Scattered TSRA over the mountains and deserts
through this evening, with strong up/downdrafts, LLWS and surface
wind gusts to 40 knots. CB bases will be around 8000 ft MSL with
tops to 45000 ft MSL. Otherwise, FEW-SCT clouds at/above 10000 ft
MSL, with vis unrestricted outside of TSRA.

&&

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

&&

.BEACHES...
Beach Hazard Statement has been extended through Saturday for
elevated surf and strong rip currents. A 4 ft/16-17 second period
swell from 180 degrees will bring surf of 3-6 ft, with isolated sets
to 9 ft, mainly along the south facing beaches of Northern Orange
County, and strong rip currents. Surf will lower Saturday night
through 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 through Saturday evening for Orange
     County Coastal Areas-San Diego County Coastal Areas.

PZ...NONE.

&&

$$

PUBLIC...MM
AVIATION/MARINE/BEACHES...Brotherton