Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 242318
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
318 PM PST Fri Nov 24 2017

.SYNOPSIS...
Cooler weather will gradually build from the coast to inland areas
through the weekend. A fast moving low pressure trough will bring
much cooler but nearly seasonable temperatures on Monday with a
chance of light rain showers for all areas except the deserts. As
marine influenced air returns, areas of dense fog could return to
coastal areas this weekend. Gusty westerly winds will develop
over the mountains and deserts Sunday night through Monday night,
turning offshore again by Tuesday morning as the trough passes to
the east. A stronger Santa Ana weather pattern with strong winds
and low relative humidity could develop around Wednesday and
persist through Friday next week.

&&

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

Thin high clouds streaming across Central and Southern California
this afternoon from the subtropics with some wave clouds noted on
the hi-res satellite loops over the Tehachapi Mountains. Far
Southern California remains mainly sunny however.

Temperatures have been trending a few degrees cooler today
although inland and mesa areas remain significantly warmer than
normal for late November with Miramar one of the warmest locations
recently hitting 94 degrees.

The high pressure ridge predominantly responsible for the recent
heat wave will gradually shift SE and replaced with a troughy
pattern through early next week. Gradually cooler conditions will
develop over the weekend with the coolest day likely to be Monday
when a vigorous upper level trough originating from the Gulf Of
Alaska passes through Central California into the Great Basin
through Tuesday. This system could bring some light rain showers
to all areas from Monday morning in Orange County through Monday
afternoon, with chances for rain added to all areas except the
deserts.

Brief offshore flow still looks to occur Tuesday morning in the
wake of the upper trough with gusts in favorable offshore canyons
and coastal slopes of 30 to 40 mph possible. At this time the
magnitude of this event looks to be moderate at best and only last
for about 12 hours.

Medium range forecaster confidence becomes quite poor Wednesday
and beyond with the EC indicating the potential for another Santa
Ana event but the strongest gradients well to the NE for Thursday
and Friday. A cutoff low may develop off the SoCal coast and
persist through the end of the work week which makes the forecast
of Santa Ana related weather conditions highly difficult this far
out. However without an upper level ridge temperatures will warm a
bit above normal but not likely to be significantly above normal.

&&

.AVIATION...
242050Z...Fog may develop after 06Z Saturday with a small chance of
vis below 1 mile and cigs below 500 ft MSL along the coast and up to
5 miles inland, although confidence is low. Any low clouds or fog
that develop tonight will burn off by 16Z Sat. Otherwise FEW-SCT
clouds AOA FL200 and unrestricted vis through Sat.

&&

.MARINE...
Areas of dense fog may develop over the coastal waters late tonight
into Saturday morning and again Saturday night into Sunday morning.
Visibility may be reduced to 1 NM or less at times.

A trough of low pressure moving through on Monday will bring
northwest winds gusting 20 to 25 kt over the outer waters.


&&

.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...PG



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