High Wind and Strong Wind in California, November 15 to 16, 2022

Area Forecast Discussion
National Weather Service San Diego CA
914 PM PST Mon Nov 14 2022

.SYNOPSIS...
Dry with high temperatures several degrees below normal Tuesday.
Gusty Santa Ana winds will develop on Tuesday night and be
strongest and most widespread on Wednesday. Winds will be weaker
on Thursday with high temperatures for Friday through the weekend
mostly near to around 5 degrees below average. Another round of
weaker Santa Ana winds is possible for Friday night and Saturday.

&&

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

EVENING UPDATE...
A few high clouds are moving over the region this evening. Surface
pressure gradients are trending strong offshore, currently -5.6
SAN-TPH and -1.7 SAN-DAG. Offshore winds remain light at this time
with gusts mostly less than 20 mph. Water vapor satellite shows
an upper level low centered near San Francisco with a vort max
off the coast. This low is progged to drop south along the coast
through Wednesday morning with increasing offshore flow behind it.
No changes to the forecast this evening as everything looks on
track.

PREVIOUS DISCUSSION...

Highlights:

* Strong Santa Ana winds Tuesday night-Wednesday; Strongest Wed AM
* Dry with near to below normal temps expected through week's end
* Weaker Santa Ana winds forecast this weekend

Water vapor imagery shows the next mid/upper level low spinning
just off the NorCal coast with a trough extending off the coast.
These features will move southeast, across SoCal on Tuesday
afternoon/evening, then to be positioned just southeast of the
region by Wednesday AM while opening up into a trough. Surface
high pressure will strengthen behind this feature over the Great
Basin through Wednesday morning, creating a tight offshore
surface pressure gradient.

Santa Ana winds strengthen Tuesday night, peaking Wednesday
morning from dawn through noon. This is the time period where
damaging winds will be possible in the favored Santa Ana wind
corridors, especially below the Cajon Pass through that portion of
the Inland Empire to the Santa Ana mountains and nearby areas.
Used a heavy hi-res model blend with some adjustments. A High Wind
Warning remains in effect from 7 PM Tue through 7 PM Wed. Peak
gusts of 60 mph are expected with localized gust in wind- prone
canyons to 70 mph. See Fire Weather discussion below for fire
weather side of things.

Temperatures will increase as winds downslope west of the
mountains, so we will see widespread 70s both Wednesday and
Thursday before cooling occurs Friday through the weekend, but
just slightly running below normal.

Another round of Santa Ana winds is likely this weekend as another
shortwave dives southeast across the Intermountain West. The
weekend round looks weaker. Dry weather conditions will continue
through the weekend. Yet another upper trough is shown by the
global models by Tuesday or Wednesday, Nov 22-23 to dive into the
region, but it is uncertain whether it will be "inside" and dry or
perhaps farther west for the potential of precipitation. Stay
tuned.

&&

.AVIATION...
150450Z...Mostly clear skies with unrestricted VIS will continue
through Tue.

&&

.MARINE...
Northeast winds will likely gust to 25 knots over parts of the
coastal waters Wednesday morning through Wednesday night. The winds
and resulting waves could produce conditions hazardous to small
craft. Otherwise, no hazardous conditions are expected through
Saturday.

&&

FIRE WEATHER...
The upcoming Santa Ana event remains on track. Weak north to
northeast winds will prevail Tuesday, becoming northeast to east
and strengthening Tuesday night, peaking Wednesday morning. Peak
gusts of 50-60 mph will occur in and below the favored passes and
canyons on the coastal slopes and adjacent foothills. Isolated
gusts of 70-75 mph are possible in the most wind-prone locations
near the Cajon Pass and northern Santa Ana Mountains.

Relative humidity will generally be around 20-25 percent during
the period of strongest winds Wednesday morning, lowering to 10-15
percent during the late morning and afternoon. The combination of
strong winds and low RH will lead to a period of critical fire
weather conditions on Wednesday, but only for 3-5 hours. Given
the short duration of critical conditions and recent significant
rainfall, no fire weather products are anticipated.

Winds will slowly weaken Wednesday afternoon into Thursday
morning, diminishing by Thursday afternoon. Another period of
Santa Ana winds is forecast for Friday and Saturday, but at this
time appears to be much weaker than the Tuesday/Wednesday evening.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...High Wind Warning from 7 PM Tuesday to 7 PM PST Wednesday 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.

PZ...Small Craft Advisory from 3 AM to 2 PM PST Wednesday 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...SS/Gregoria
AVIATION/MARINE...PG