626
FXUS66 KSGX 081702
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
902 AM PST Wed Jan 8 2025

.SYNOPSIS...
North to northeasterly Santa Ana winds will continue today with
widespread critical to locally extreme fire weather conditions.
Lingering Santa Ana winds and dry air will bring periods of critical
fire weather conditions Thursday and Friday, although winds are
expected to be weaker than their peak today. Warmer weather will
occur Thursday, with slight cooling Friday with increased winds
again, then warmer again Saturday with weaker winds. Cooler and
breezy weather will prevail early next week.

&&

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

Periods of north to northeast Santa Ana winds will continue through
Friday. A peak wind gust summary has been headlined on our
weather.gov/sandiego homepage. The peak gusts so far have been 94
mph at Freemont Canyon, 92 mph at Arrowhead Springs, and 89 mph near
Lytle Creek. Winds today will start to decrease from their peak and
become more localized into this afternoon, with a continued
weakening into Thursday morning. Winds are expected to increase
again late Thursday afternoon into Friday morning. The strongest
winds are expected to be more localized to mountains, foothills,
and below passes Thursday into Friday. Locally extreme fire
weather conditions expected through 1 PM for inland Orange County,
Santa Ana mountains, the Inland Empire, and foothills of the San
Bernardino mountains. Critical fire weather conditions will
continue into Friday. More information can be found in the fire
weather discussion below.

Moisture closer to the center of the upper low over northwestern
Mexico could bring some showers to the east slopes of the mountains
through 11 AM with the most likely location for measurable
precipitation over the mountains of southern San Diego County.
High temperatures today will be a few to around 5 degrees warmer
than Tuesday, 5 to locally 10 degrees above average for coastal
areas and 5 to 10 degrees below average for the mountains. Inland
areas will continue to warm on Thursday with the coast a few
degrees cooler.

Warmer inland and cooler for the coast on Saturday. Then
cooling for Sunday into early next week as another low pressure
system from the north develops in the vicinity of southern
California with continuing differences in placement. Some solutions
indicate a more inland track with could bring another round of Santa
Ana winds, while others indicate a more westward track.

&&

.AVIATION...
081650Z...BKN clouds with bases around 8000-10000 feet MSL, and
isolated terrain obscurations on mountain peaks will continue across
mountains and deserts through about 19Z. Otherwise, SCT clouds AOA
20K ft MSL will continue through today.

Strong northeasterly winds 25-45 kts for areas along and west of the
mountains today. Higher gusts over 55 kts continuing this morning
over coastal foothills and into adjacent valleys. Gusty winds will
continue through 21Z and gradually decrease thereafter. These winds
will generate areas of BLDU with reduced vis 3-5SM, along with areas
of LLWS and strong up/downdrafts in lee of mountains.

Gusty winds will become more confined to foothills after 03Z Thurs,
but restrengthen in all areas Thursday evening into Friday morning.

&&

.MARINE...
Offshore winds of 20-30 kt will continue into early afternoon and
gradually decrease thereafter. This will result in choppy seas and
hazardous boating conditions. A Small Craft Advisory is in effect
containing more details. East winds locally going over 20 kts by
Thursday night near the SD Co coastline. No additional hazardous
marine conditions are expected Friday into the weekend.

&&

.FIRE WEATHER...
A Particularly Dangerous Situation is expected for inland Orange
County, Santa Ana mountains, Inland Empire, and foothills of the
San Bernardino mountains through to 1 pm due to a period of
widespread strong winds, very dry air, and critically dry fuels.
The strongest wind gusts likely occurred overnight, but gusts 50
to 60 mph, with a few local gusts to 70 mph possible in wind prone
mountain locations through the late morning. Gusts 40 to 50 mph
are expected in the San Diego valleys and Orange County coast.
Winds will weaken and become more localized this afternoon, with
strongest gusts 35 to 50. Dry air will settle over the area
today. Relative humidity values on Wednesday are expected to fall
to 10 to 15 percent for Orange County and the Inland Empire,
locally down to 8 percent in the Inland Empire. For San Diego
County and the Riverside County mountains minimum relative
humidity will fall to the 10 to 20 percent range with those higher
values more likely in the San Diego County mountains.

Overnight humidity recovery the next few night will be poor. For
most inland areas, maximum relative humidity overnight will only
reach 15 to 25 percent, with max relative humidity closer to 30
percent near the coast and higher elevations in the mountains.
Minimum relative humidity for inland areas Thursday is expected to
fall to the 8 to 15 percent range. Winds will weaken and become
more localized by Thursday morning, but another peak in Santa Ana
winds is expected for late Thursday afternoon into Friday morning.
Winds during that peak will be strongest in places more prone to
northeast/easterly winds. The strongest winds will be mostly
confined to coastal mountain slopes, foothills, and below passes.
Peak gusts will be 40 to 60 mph, with the potential for gusts to
reach up to 75 mph in the San Diego mountain foothills late
Thursday night or early Friday morning. Critical fire weather
conditions are expected through Friday, with the elevated winds
being combined with low relative humidity.

&&

.CLIMATE...
With no rainfall expected today for San Diego, this will be the
driest start ever to the July 1st to June 30th California rainfall
year and for the October 1st to September 30th water year for San
Diego with only 0.14 inch of rainfall from October 1st through today
and 0.16 inch for July 1st through today. Rainfall records for San
Diego go back to 1850.

&&

.SKYWARN...
Skywarn activation is requested.


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...High Wind Warning until 2 PM PST this afternoon for Orange
     County Coastal Areas-San Diego County Coastal Areas.

     High Wind Warning until 6 PM PST this evening for Orange County
     Inland Areas-Riverside County Mountains-San Bernardino
     County Mountains-San Bernardino and Riverside County
     Valleys-The Inland Empire-San Diego County Mountains-San
     Diego County Valleys-San Gorgonio Pass Near Banning-Santa
     Ana Mountains and Foothills.

     Red Flag Warning until 6 PM PST Thursday for Orange County
     Inland Areas-Riverside County Mountains-Including The San
     Jacinto Ranger District Of The San Bernardino National
     Forest-San Bernardino County Mountains-Including The
     Mountain Top And Front Country Ranger Districts Of The San
     Bernardino National Forest-San Bernardino and Riverside
     County Valleys  -The Inland Empire-San Diego County Inland
     Valleys-San Diego County Mountains-Including The Palomar
     And Descanso Ranger Districts of the Cleveland National
     Forest-San Gorgonio Pass Near Banning-Santa Ana Mountains-
     Including The Trabuco Ranger District of the Cleveland
     National Forest.

     Wind Advisory until 2 PM PST this afternoon for Apple and
     Lucerne Valleys.

     Red Flag Warning until 6 PM PST this evening for Orange County
     Coastal Areas.

PZ...Small Craft Advisory until 1 PM PST this afternoon for Coastal
     Waters from San Mateo Point to the Mexican Border and out
     to 30 nm-Waters from San Mateo Point to the Mexican Border
     Extending 30 to 60 nm out including San Clemente Island.


&&

$$

PUBLIC/FIRE WEATHER...CO/17
AVIATION/MARINE...APR
CLIMATE...17