High Wind in California, March 10 to 12, 2022

Area Forecast Discussion
National Weather Service San Diego CA
924 PM PST Wed Mar 9 2022

.SYNOPSIS...
A trough of low pressure moving in from the north tonight, combined
with a strengthening Catalina Eddy over the coastal waters will
deepen the marine layer and spread low clouds onto the coastal
slopes by Thursday morning. From Thursday evening through Friday
afternoon, strong Santa Ana winds will follow over the mountains,
foothills, portions of the Inland Empire and inland Orange County.
As the trough moves east, fair and warmer weather will return for
the weekend.

&&

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

Low clouds developed rapidly along our coast late this afternoon,
and have been spreading slowly inland this evening. A coastal eddy is
spinning up offshore as well, turning winds S-SE along the coast. A
moderate southerly flow will persist through midday Thursday. Those
winds and clouds will keep it much warmer tonight after another
chilly night with record lows last night at Ramona(29) and Thermal
(32). Our 00Z Miramar sounding showed some moistening below 10K FT,
and a flip to S-SW winds below 3K FT MSL. The sfc pressure gradients
across SoCal weren't strong, but are trending solidly onshore now,
and at 8 PM PST, west wind gusts had reached 40+ MPH along and below
the San Gorgonio Pass.

West winds will increase a bit more over the mts/deserts tonight,
then turn from the north on Thursday from north to south through the
day. At this time, the San Diego deserts are not included in the
Advisories, but there will be periods of gusty winds here as well,
especially near the desert foothill areas tonight and again Thursday
evening. A few convective cells are possible over San Diego County
late in the day, due to sharp cooling aloft, and sfc convergence,
especially along the mountains. Not enough of a threat at this point
for any forecast changes tonight.

From previous discussion...

Again with the wind. This time it will be a Santa Ana wind impacting
the area Thursday evening through Friday afternoon. But before we
get the offshore wind we will have onshore flow and a deepening
marine layer from a Catalina Eddy that is spinning up over the
coastal waters this afternoon. Low clouds over the coastal waters
this afternoon will spread eastward into the coastal zones and
western valleys through Thursday morning.

A strong 500 mb trough digging down the coast tonight will pivot
across Southern California Thursday afternoon. There may be a few
showers ahead this trough Thursday, but it is moisture starved, and
the 12Z model runs have trended lower with the precip chances and
precip amounts. The EC ensembles only show a 50% chance of 0.10" of
rain in a small area of the San Diego County foothills and western
mountain slopes.

Of greater impact will be the Santa Ana winds behind the trough.
They will be strongest in the San Bernardino Mountains, the San
Gabriel Mountains, the Inland Empire, and parts of Orange County.
Wind gusts of 40-60 mph are likely in these areas, with peak gusts
of 65-75 mph in the most wind-prone sites like Marshall Peak and
Fremont Canyon.

The San Diego County Mountains were added to the Wind Advisory as
well for winds of 25-35 mph with gusts to 55 mph.

The offshore winds start to fade Friday afternoon. High pressure
aloft over the Southwest will bring a sunny, dry day Saturday with
light winds. On Saturday night a weak trough passing through central
California will bring some cooling west of the mountains. Then it
will turn much warmer Monday and Tuesday with renewed ridging over
the Southwest with highs in the 70s and 80s west of the mountains,
60s in the mountains, 70s in the high desert, and near 90 in the
lower desert.

&&

.AVIATION...
100500Z...Low clouds will continue to fill the coastal basin and
into the valleys overnight, with bases 1500-2000 FT MSL. A coastal
eddy will deepen the marine layer with low clouds and fog spreading
inland and bases rising to 2000-2500 FT MSL after midnight. Slight
CHC -SHRA after 12z Thu with reduced vis 3-5 SM possible.

Inc W-NW winds tonight, with peak wind gusts of 35-45 kt possible
after 12Z Thu, with local gusts to 50 kt. MOD-STG up/downdrafts and
LLWS over/east of the mtns. Rotors possible vcty KPSP/KTRM. Winds
will begin to turn offshore after 17z Thu with STG winds expected
through Fri.

&&

.MARINE...
No hazardous marine conditions are expected through Thursday
afternoon. Breezy northeast winds will develop Thursday evening
across the coastal waters with peak wind gusts of 25 to 30 knots.
Gusty winds and choppy seas will lead to conditions hazardous to
small craft. Winds will decrease through Friday morning, and no
hazardous marine conditions are expected Friday afternoon through
Sunday.
&&

.SKYWARN...
Skywarn activation is not requested.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory from 3 PM Thursday to 3 PM Friday for Orange
     County Inland Areas-Riverside County Mountains-San
     Bernardino County Mountains-San Bernardino and Riverside
     County Valleys-The Inland Empire-Santa Ana Mountains and
     Foothills.

     Wind Advisory from 10 PM Thursday to 3 PM Friday for San
     Diego County Mountains.

     Wind Advisory from 10 AM to 10 PM Thursday for Coachella
     Valley-San Gorgonio Pass Near Banning.

     Wind Advisory until 6 PM Thursday for Apple and Lucerne
     Valleys.

PZ...Small Craft Advisory from 7 PM Thursday to 4 AM Friday 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...10/Moede
AVIATION/MARINE...JMB