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000 
FXUS66 KSGX 201017
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
317 AM PDT Thu Jul 20 2017

.SYNOPSIS...
Generally fair and summer-like weather is forecast this coming 
week. Monsoon moisture decreases today and dry weather will 
result through Sunday. Coastal low clouds will return each night 
and morning. A small surge of monsoonal moisture early next week 
may trigger a few afternoon thunderstorms over the mountains 
Monday.

&&

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

A hot ridge of high pressure is anchored over the nation's
midsection, while a trough lies over the Pacific Northwest into 
northern sections of California. This will result in a predominant
westerly wind flow, allowing moisture to decrease across the area
today-Fri. Some hi-res models show light QPF over the San Diego 
County mountains where relatively higher moisture will reside. 
Placed a slight chance of showers there today. Otherwise, dry 
weather is forecast through the weekend. Heights will gradually 
rise Fri-Sat, leading to warming temps inland. 

The ridge will slide east early next week with an increase in
moisture from the Southeast. It does not look to be anything
significant, but enough to include a slight chance of thunderstorms
for the mountains. The moisture though does not hang around long as
both GFS and ECMWF show drying occurring again during the middle 
to latter part of next week as another trough moves towards the 
U.S. west coast. Models differ on the amplitude of the trough, but
either way, this synoptic pattern does not bode well for 
monsoonal convection here for most of next week. Temps will be
seasonable.

&&

.AVIATION... 
200950Z...Coast/Valleys...Areas of SCT-BKN stratus will continue to 
develop along the coast this morning, spreading up to 20 miles 
inland by 12Z. Bases will be 900-1300 ft MSL with tops to 1500 ft 
MSL. Local vis 3-5 miles will occur on elevated coastal terrain. 
Most areas will clear 15Z-17Z. Areas of stratus will likely develop 
again aft 03Z Fri along the coast, but confidence in timing is low. 
Otherwise, SCT-BKN clouds at/above 12000 ft MSL will continue 
through today, decreasing in coverage tonight.

Mountains/Deserts...SCT-BKN clouds at/above 12000 ft MSL will 
continue through today, with fewer clouds tonight. Unrestricted vis 
through Thu night.

&&

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

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.
&&

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