Area Forecast Discussion
Issued by NWS San Diego, CA

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877
FXUS66 KSGX 181740
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
940 AM PST Sat Nov 18 2017

.SYNOPSIS...
Warm and dry this weekend with weak high pressure building over the
region. It will be even warmer next week as the high strengthens
over the Southwest with record warmth quite likely Thanksgiving Day.

&&

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

The weather will be warm this weekend. The weather will be even
warmer next week.

Weak ridging aloft brought in a much drier airmass today as the PW
fell from 1.04" last night to 0.55" this morning. A testament to
this drier air is the lack of mid and high clouds that we`ve had the
last few days. A weak Santa Ana weather pattern is in place this
morning with a 1036 mb surface high over Utah generating localized
northeast winds in the mountains and passes. At 9 am, winds were
gusting to 27 mph at Fremont Canyon, 25 mph at Sierra Peak, 30 mph
at Campo, and 24 mph at Cabazon and Devore.

This weekend will mostly clear and mild with high pressure slowly
building in from the west. Nights will be clear and cool with
temperatures falling into the low to mid 30s in parts of the high
desert where patchy frost is likely.

The real warmth arrives next week when the ridge aloft amplifies to
a 594 dm high over northern Baja on Thanksgiving Day. Record highs
are quite likely Wednesday and Thursday. See the CLIMATE section
below for the record temperatures. Surface high pressure over the
Great Basin will maintain weak offshore low level flow, and high
temperatures will be way above average in all areas. Valley highs
will be in the 90s, and the coastal zones will see highs in the 80s.
The mountains will be in the 60s and 70s, the high deserts in the
80s, and the low deserts in the 90s.

Next weekend the ridge aloft weakens for minor cooling, but
temperatures will still be above average.

&&

.AVIATION...
181615Z...Coast/Valleys...A few patches of fog over the coast and
valleys this morning, with local vis down to 1/4 sm, will continue
to clear through 1800 UTC, while otherwise P6SM vis and mostly SKC
continues. 1800-19/0400 UTC, P6SM vis and mostly SKC. 19/0400-1500
UTC, some patches of low stratus/dense fog (with bases 200-400 ft
msl, tops 500-800 ft msl, and local vis 1/4 sm or less) may develop
within 5-10 sm of the coast, with possible impacts to KSAN, KSNA and
KCRQ, but confidence is low. Otherwise/Elsewhere, expect P6SM vis
and mostly SKC.

Mountains/Deserts...P6SM vis and mostly SKC through Sunday morning.

&&

.MARINE...
No hazardous marine conditions are expected through Wednesday.

&&

.CLIMATE...
Forecast highs Wednesday and Thursday compared to the record highs.

           Wednesday                Thursday
        Forecast/Record         Forecast/Record

San Diego.....84/84                   83/86
Riverside.....91/90                   91/91
Ramona........91/85                   91/89
Big Bear......68/65                   69/68
Palomar Mtn...75/74                   76/75
Palm Springs..92/93                   94/94
Borrego.......90/87                   91/88

&&

.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...Moede
AVIATION/MARINE...Harrison



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