Area Forecast Discussion
Issued by NWS San Diego, CA

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FXUS66 KSGX 280947
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
247 AM PDT WED SEP 28 2016

.SYNOPSIS...
A mid to upper level low will continue to move northward over the
area today, bringing variable mid and high clouds and the
potential of a few showers and thunderstorms, mostly in the
mountains. The low will northeast of the local area Thursday
through Friday... followed by a longwave trough moving in this
weekend and into early next week. This will lead to gradual
cooling through the end of the week as onshore flow strengthens
and the marine layer slowly returns. It will turn much cooler by
the weekend with gusty westerly winds over the mountains and
deserts.

&&

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

Water vapor imagery shows a mid/upper level low over Southern
California. This low will slowly drift north and just enough
moisture looks to be present for the potential of a few showers or
even thunderstorms, mainly over the mountains. Hi-res models show
activity focused over the Riverside and San Bernardino Mountains
so this is where POPS are the highest. There is a lesser chance of
activity in the Inland Empire to the high deserts.

The low will move northeast of the area Thu-Fri and much of the
moisture will be taken with it. POPS were lowered with just a
slight chance of showers in the San Bernardino Mountains tomorrow
and have it dry everywhere by Friday.

Temperatures will continue on the warm side...but nothing like
the heat we saw Sun-Mon west of the mountains as the pressure
gradients continue trending onshore. More appreciable cooling is
forecast this weekend into early next week as a longwave trough
is forecast to amplify along the West Coast. This will bring
temperatures below average. Marine stratus will return this
weekend into early next week, extending further inland each night
as the marine layer deepens. Gusty onshore winds will develop at
times in the mountains and deserts, mainly during the afternoons
and evening. Dry weather will prevail this weekend into early next
week.

&&

.AVIATION...
280900Z...Variable clouds above 10000 feet msl will continue today
and tonight. A few thunderstorms are expected in the mountains with
a very slight chance in far inland valleys and the deserts from 19-
01Z this afternoon. Any storms that form may reduce visibility and
produce gusty, erratic winds. Tstorm cloud bases would be around
8000 feet msl with tops rising to 30000 feet.

&&

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

&&

.BEACHES...
An increase in south swell is expected to boost surf Friday through
the weekend. Expect occasional sets to 6 feet, particularly in
Orange County, and a high rip current risk.

&&

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

&&

.SGX Watches/Warnings/Advisories...
CA...None.
PZ...None.
&&

$$

PUBLIC...Gregoria
AVIATION/MARINE...MM



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