Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 232208
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
208 PM PST Thu Nov 23 2017

.SYNOPSIS...
High pressure aloft near the West Coast and weak offshore flow will
continue to provide record-setting hot temperatures today for many
areas. The cooling will spread slowly inland Friday into the weekend
with greater cooling Sunday and Monday with stronger and gusty west
winds in the mountains and deserts. There is the potential for a
moderate strength Santa Ana wind event next Tuesday into Wednesday,
with the strongest and most widespread winds on Tuesday.

&&

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

Very warm conditions across all areas today due to the combination
of light offshore flow and very warm high pressure aloft.
Meanwhilethe southern periphery of a high cloud shield is
affecting the northern portion of the CWA and could keep
temperatures from warming up much more there. Areas of San Diego
County will still see several records tied or broken, with San
Diego already tying the record high temperature of 86 degrees.

Offshore gradients are weaker today than compared to yesterday and
this morning, peaking attm about 6 mb from San Diego to Tonopah.
Offshore gradients will continue to weaken through Friday but
temperatures aloft will remain unseasonably warm and thus inland
temperatures will not see nearly as much relief from the heat
Friday as locations closer to the coast, where marine modified air
will help to cool things down considerably.

For Saturday through Monday, a troughy pattern will develop with a
weak frontal boundary and trough passage early Monday. Although
predicted moisture is meager there could be a few showers with the
front if it holds together by the time it gets to Southern
California. Stronger onshore flow will bring strong gusty winds
through the passes and the desert slopes.

Another offshore pattern then develops for Tuesday through
Wednesday with a chance for near critical fire weather conditions
and abnormally warm temperatures west of the mountains.

&&

.AVIATION...
232037Z...P6SM vis and SCT clouds AOA 20000 ft msl through about
24/0800 UTC. 24/0800-1600 UTC, there`s a chance that dense fog/low
stratus clouds (with bases 100-300 ft msl, tops around 500-700 ft
msl, and local vis of 1/4 sm or less) will develop within 5 sm of
the coast, possibly impacting KSAN and KCRQ, with lesser chances for
KSNA. However, confidence in dense fog occurrence remains low at the
moment. Otherwise/elsewhere, P6SM vis and SCT-BKN clouds AOA 20000
ft msl will continue.

&&

.MARINE...
No hazardous marine weather is expected through Tuesday except for
potentially gusty northwest winds to 25 kt over the outer waters
Monday.


&&

.FIRE WEATHER...
Elevated fire weather conditions will continue today for inland
areas with lowest humidities around 15 percent. Northeast winds
near the coastal foothills will be weaker than on Wednesday with
gusts mostly 30 mph or less this morning. Humidities will slowly
recover for Friday through the weekend.

For next Tuesday and Wednesday...a moderate strength Santa Ana
wind event is possible with lowest daytime humidities of 5 to 10
percent...and with the strongest and most widespread northeast
winds on Tuesday.

&&

.CLIMATE...
High temperatures forecast to be tied or broken today:

Location       Forecast       Current Record
San Diego         86              86 in 1950
Vista             89              83 in 1975
Chula Vista       89              87 in 1924
Riverside         92              91 in 1995
Escondido         92              90 in 1949
El Cajon          94              86 in 1995
Ramona            91              89 in 1995
Alpine            89              86 in 1995
Big Bear Lake     72              68 in 1981
Idyllwild         76              75 in 1954
Palomar Mountain  77              75 in 1954
Campo             89              82 in 1995
Palm Springs      91              94 in 1950
Thermal           91              93 in 1950
Borrego Springs   90              88 in 1989

There will likely also be some record warm minimum temperature
records set...and a few additional high temperature records may be tied
or broken on Friday.

&&

.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...Brotherton
AVIATION/MARINE...Harrison



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