National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS66 KSGX 211014
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
314 AM PDT Mon Oct 21 2019

.SYNOPSIS...
Warmer and dry weather will continue through Tuesday with periods
of gusty northeast winds near the coastal slopes of the mountains.
A little cooler for coastal and valley areas on Wednesday with
weaker offshore flow. Stronger offshore flow with strong and gusty
northeast winds is possible on Thursday with weakening winds on
Friday. This will continue above average high temperatures for
Thursday and Friday. Onshore flow is expected to return and
strengthen next weekend spreading cooling inland.


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

.SHORT TERM (Today through Wednesday)...
High pressure aloft and weak offshore flow will continue a warm
trending into Tuesday for the coast and valleys and into Wednesday
in the deserts.

There will continue to be gusty northeast winds near the coastal
slopes of the mountains and below passes and canyons. Winds will
be strongest and most widespread each day from late at night into
the morning with stronger gusts to around 35 mph.

High pressure aloft and offshore flow will weaken on Wednesday
with high temperatures around 5 degrees cooler for coastal and
valley areas.

&&

.LONG TERM (Thursday through Sunday)...
A period of stronger offshore flow with stronger and gusty
northeast winds is possible on Thursday with high pressure aloft
over the eastern Pacific, a trough of low pressure over the
Rockies, and surface high pressure over the Great Basin. There is
greater model spread for Thursday night into Friday on how quickly
the trough of low pressure over the Rockies moves eastward into
the Great Plains and how quickly surface high pressure over the
Great Basin weakens. This will affect the degree to which the
offshore winds weaken and become less widespread on Friday.

Onshore flow is expected to return next weekend and strengthen.
This will spread cooling inland with a return of coastal low
clouds possible for Saturday night into Sunday morning.

&&

.AVIATION...
210900Z...Clear skies expected today and tonight. Northeast sfc
winds gusting 20-25 kts through about 20Z, mainly in the foothills
and adjacent valleys. Pockets of LLWS S/SW of the mountains.

&&

.MARINE...
No hazardous marine weather is expected through Friday.

&&

.FIRE WEATHER...
Weak offshore flow will continue into Tuesday with lowest inland
humidity of 10 to 15 percent today and around 10 percent Tuesday.
There will continue to be gusty northeast winds near the coastal
slopes of the mountains and below passes and canyons. The winds
are expected to be stronger and more widespread this morning and
again late tonight into Tuesday morning with strongest gusts to
around 35 mph. This will continue elevated fire weather
conditions for the coastal slopes of the mountains into the inland
valleys into Tuesday.

Stronger offshore flow is possible on Thursday with areas of
strong and gusty northeast winds from the coastal slopes of the
mountains into the inland valleys and inland Orange County. Lowest
inland humidity could fall to 5 to 10 percent Thursday and around
5 percent Friday. There is greater model spread for Thursday
night and Friday on just how quickly the northeast winds will
weaken and become less widespread. Critical fire weather
conditions are possible for the mountains, valleys, and inland
Orange County on Thursday with elevated to critical fire weather
conditions continuing and Friday.

Onshore flow is expected to return for next weekend with cooling
and higher coastal humidity spreading inland.

&&

.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/FIRE WEATHER...17
AVIATION/MARINE...MM