Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 232041
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
141 PM PDT Wed Aug 23 2017

.SYNOPSIS...
Below normal high temperatures and a deep marine layer will
continue through Thursday. Patchy drizzle is expected again over
portions of the coast and valleys Thursday morning. High pressure
building near the region will create above normal high
temperatures this weekend into early next week, with temperatures
peaking Monday.

&&

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

At 1 PM PDT, water vapor satellite imagery displayed an upper-
level low just off the coast of Point Conception, and an upper-
level ridge over New Mexico. Visible satellite showed a deep
marine layer, with low clouds having a very hard time clearing
over coastal areas and western valleys in San Diego county. Low
pressure aloft will maintain a deep marine layer west of the
mountains through Thursday, with below normal high temperatures
continuing through the period and patchy drizzle possible again
Thursday morning.

The aforementioned ridge will build northwest by the end of the
weekend, and hover over Nevada through early next week. This will
transition us from the extended below normal high temperatures to
above normal high temperatures by the weekend. H850 temperatures
increasing to around 31 C will yield highs 5 to 10 F above normal
by Monday. Heat Advisories or Excessive Heat Warnings may be
needed. Highs will range from 100-110 F in the Inland Empire and
the High Deserts, and from 110-115 F in the Lower Deserts.
Afternoon inland thunderstorms may return to the forecast by mid
week next week as the upper-level high transitions back towards
the southeast.

&&

.AVIATION...
232000...Coast/Valleys...Low clouds with bases 1000-1700 ft MSL
continuing along the coast and up to 10 SM inland this afternoon. We
should see stratus scatter out to within a couple miles of the coast
by 21Z this afternoon. Low clouds beginning to move back inland
around 25/00Z and spreading into the valleys overnight. Bases will
be near 1500-2000 ft MSL, and continue through Thursday morning.
VSBY restrictions 2-4 SM at times where clouds near higher terrain
in the valleys.

Mountains/Deserts...SCT afternoon cumulus with an isolated shower
not out of the question over the ridges and unrestricted visibility
through Thursday. Gusty diurnal winds each afternoon and evening
over the mountains and desert slopes with gusts to 35 knots at times.

&&

.MARINE...
Wind gusts around 20 knots this afternoon and evening on the outer
waters. Otherwise no hazardous marine weather is expected through
Sunday.

&&

.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...JJT
AVIATION/MARINE...Brotherton



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