Area Forecast Discussion
Issued by NWS San Diego, CA

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540
FXUS66 KSGX 241038
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
338 AM PDT Mon Apr 24 2017

.SYNOPSIS...
A low pressure system moving inland to the north today will bring
stronger onshore flow with strong gusty west winds in the
mountains and deserts...inland cooling...and coastal low clouds
extending into the inland valleys. Slightly warmer on Tuesday
with greater warming and weaker winds on Wednesday under high
pressure aloft. A trough of low pressure moving southeastward
through the Great Basin will bring stronger onshore flow for
Thursday night and Friday with cooling...followed by weaker
offshore flow for Saturday with warming for next weekend as high
pressure strengthens off the West Coast.

&&

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

.SHORT TERM (Today through Wednesday)...
A low pressure system moving inland to the north today will bring
stronger onshore flow through tonight. Significant cooling that
developed over most areas except for the lower deserts on Sunday
will spread farther inland today. Gusty west winds in the
mountains and deserts will strengthen with strongest winds for
late afternoon through late evening. The marine layer has deepened
to around 3000 feet with coastal low clouds extending into the
far inland valleys early this morning. A deep marine layer will
continue into Tuesday morning...then become shallower into
Wednesday as high pressure over the subtropical eastern Pacific
expands into California. High temperatures will warm to near
average on Tuesday and around 5 degrees above average on
Wednesday.

&&

.LONG TERM (Thursday through Sunday)...
A low pressure system will move southeastward through the Great
Basin on Thursday. This will bring stronger onshore flow across
Southern California for Thursday night and Friday with strong
gusty west winds in the mountains and deserts. Slow cooling will
develop west of the mountains on Thursday and spread farther
inland on Friday with high temperatures on Friday cooling to near
average. Weaker offshore flow will follow for Friday night into
Saturday with locally gusty north to northeast winds. High
pressure aloft off the West Coast will bring warming for next
weekend beginning west of the mountains on Saturday and spreading
farther inland on Sunday.

&&

.AVIATION...
240900Z...Coast/Valleys...Low clouds will shroud most of the coastal
basin this morning through 17Z. Bases will be 1500-2000 feet msl
with tops up to 3000 feet. Areas of vis reduced where clouds and
terrain intersect. Low clouds to return mainly in San Diego county
after 03Z this evening with bases 2000-2500 feet msl.

Mountains/Deserts...West winds with gusts 25-45 kt will produce mod-
stg up/downdrafts and LLWS over and east of the mountains this
afternoon through tonight.

&&

.MARINE...
Northwest winds will increase today and continue through Tuesday
evening with gusts to 25 knots. The winds and building swell will
produce combined seas of 10-12 feet. A small craft advisory is in
effect through Tuesday evening in the outer waters. Winds and seas
could be hazardous again Thursday through Friday.

&&

.BEACHES...
Mixed swell will produce above average surf with some sets reaching
7 feet today. A Beach Hazards statement in effect and the surf
forecast detail the hazards.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory from 2 PM this afternoon to 3 AM PDT Tuesday for
     Apple and Lucerne Valleys-Coachella Valley-Riverside County
     Mountains-San Bernardino County Mountains-San Diego County
     Deserts-San Diego County Mountains-San Gorgonio Pass Near
     Banning.

     Beach Hazards Statement through this evening for Orange County
     Coastal Areas-San Diego County Coastal Areas.

PZ...Small Craft Advisory from 5 PM this afternoon to 10 PM PDT
     Tuesday for Waters from San Mateo point to the Mexican
     Border Extending 30 to 60 nm out including San Clemente
     Island.

&&

$$

PUBLIC...17
AVIATION/MARINE/BEACHES...MM



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