Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 220304
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
804 PM PDT Mon Aug 21 2017

.SYNOPSIS...
Low pressure centered off the Southern California coast will keep
temperatures a few degrees below normal through midweek...with
areas of low clouds and patchy fog nights and mornings. Warmer
for the latter half of the week as high pressure builds over
the Great Basin. Daytime highs could be several degrees above
average again by the weekend.

&&

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

At 8 PM PDT...skies were mostly clear across the forecast area. A
few higher clouds were drifting slowly north over the desert areas
to the east, and the marine stratus was very limited offshore. The
00Z Miramar sounding had a a 7.5 degree C inversion based near
2360FT MSL. The column remained quite stable and dry with 5-10 KT
S-SE winds below 12K FT, turning SW and increasing above. The sfc
pressure gradients had turned weakly offshore from NV, and weakened
a bit onshore to the lower deserts. Peak westerly wind gusts over
the mts/deserts were mostly below 25 MPH.

Looks like the marine stratus will cover much less territory the
next few nights. Otherwise, little change. The forecast was updated
earlier in the evening to remove POPS from the mts/deserts.

From previous discussion...

The troughy pattern along the coast will continue through Tuesday
with continued unseasonably deep marine layer influence. Low
pressure will weaken Wednesday through Friday, bringing a weaker
marine layer, and gradual warming trend to near-normal.

High pressure ridging will develop late in the weekend and into
early the following week, bringing some additional warming to a
bit above normal conditions, especially for inland locations. In
addition, some return mid level monsoonal flow will develop and
may eventually bring another chance of convection to the
mountains and deserts, although not enough confidence yet to add
to the extended forecast.

&&

.AVIATION...
220300Z...Coast/Valleys...A slow and only patchy return of the
marine layer low clouds to areas within 25 SM of the coast is
anticipated through 14Z Tuesday. Where clouds due return, bases will
be near 1500 ft msl and tops should be around 2200 ft msl.
Visibility restrictions of 3-5 SM are possible near higher terrain.
Clearing to the coast should occur between 15Z and 17Z Tuesday.
Light westerly sea breezes and clear skies are anticipated between
18Z Tuesday and 03Z Wednesday.

Mountains/Deserts...Mostly clear skies and unrestricted visibility
through Tuesday evening.

&&

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

&&

.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...JAD/Brotherton
AVIATION/MARINE...Albright


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