National Weather Service Forecast Discussion

Dicussion provided by the National Weather Service Forecast Office located in San Diego, California

000
FXUS66 KSGX 182139
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
139 PM PST Sat Nov 18 2017

.SYNOPSIS...
Clear and cool weather tonight will be followed by a sunny, warm
day Sunday with weak high pressure building over the region. It
will be even warmer all of next week as the high strengthens over
the Southwest. Record warmth is likely Wednesday and Thanksgiving
Day.

&&

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

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 weak Santa
Ana weather pattern is in place today with a 1034 mb surface high
over Utah brought localized northeast winds in the mountains and
passes this morning with peak gusts of 43 mph at Highland Springs,
37 mph at Pleasants Peak, and 30 mph at Rialto and Crestline
Ridge.

Clear and cold tonight with light winds. Dewpoints plummeted from
the 30s in the high deserts this morning into the teens this
afternoon. Expect overnight lows to fall into the upper 20s and
low 30s in parts of the high deserts tonight. A Frost Advisory is
in effect through 8 am Sunday. It will also be quite cool in some
of the Inland Valleys where patchy frost is possible in the wind
sheltered areas.

It will turn unseasonably warm next week as the ridge aloft
amplifies to a 594 dm high over northern Baja by 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...
182108Z...Coast/Valleys...Through 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 (with lesser chances at KCRQ and KSNA) 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 Thursday.

&&

.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....91/93...................93/94
Borrego.........89/87...................91/88

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Frost Advisory from midnight tonight to 8 AM PST Sunday for
     Apple and Lucerne Valleys.

PZ...NONE.
&&

$$

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

NWS SGX Office Area Forecast Discussion