000
FXUS66 KSGX 221633
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
833 AM PST Sat Jan 22 2022

.SYNOPSIS...
Strong Santa Ana winds will continue today across the mountains,
coastal foothills and the valleys before weakening tonight.
Isolated showers and high-elevation snow showers will be possible
tonight into early Sunday morning. Winds will turn back onshore
briefly on Monday, bringing cooling to areas west of the
mountains and warming in the deserts. A ridge of high pressure
will then rebuild across the western United States midweek,
bringing warm and dry conditions to Southern California.

&&

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

Strong Santa Ana winds continue across Southern California this
morning. So far, the peak wind gusts have occurred at Toro Peak
(Riverside County) at 83 mph, and Fremont Canyon (Orange County)
at 82 mph. Surface pressure gradients remain strong this morning,
with -12.9 from SAN to TPH. An intense upper-level low is
progressing southward into northwestern Mexico; this low will
begin to weaken through the rest of today as it slowly drifts
southward, allowing for the winds to begin to diminish later this
afternoon and evening across the inland valleys. Winds will
remain breezy through the overnight hours across the mountains and
coastal foothills before relaxing on Sunday. High temperatures
today will warm several degrees above the observed highs on Friday
across coastal areas but will cool elsewhere.

Mid-level moisture will continue to wrap around northern and
eastern portions of the low today. Scattered showers and high-
elevation snow showers will be possible tonight into early Sunday.
Snow levels will start as low as 4500 ft this evening but rise to
near 5000 ft overnight. Precipitation will remain light, with some
locations picking up a trace to an inch of snow by Sunday morning.

Previous Discussion (Issued 410 AM PST Sat Jan 22 2022)...

Santa Ana winds were in full force Friday night with a gust of 78
mph at Toro Peak and 74 mph at Keen Ridge, both in the Riverside
County Mountains. In the Inland Empire, damaging winds blew down
trees and power lines below the Cajon Pass from Rancho Cucamonga to
Loma Linda. A semi was blown over on I-15 near Fontana.

The strong winds were brought on by a combination of double-digit
offshore surface pressure gradients from the 1038 mb Great Basin
high, and the strong northeast 45-50 kt 850 mb winds associated with
the deep closed low over the Lower Colorado Valley. Strong Santa Ana
winds this morning will slowly subside later this afternoon and
overnight tonight. That`s when the winds aloft decrease and the
upper low drifts southeast over the Sonoran Desert.

There is a chance for snow showers in the mountains tonight as wrap
around moisture in broad cyclonic flow around the upper low moves in
from the east. Best chances will be on the eastern slopes and the
mountain tops of the San Bernardino and Riverside County mountains.
The HRRR and the WRF project less than a 1/10th of an of precip
which equates to anywhere from a Trace to about an inch of snow in
those mountain areas that do see snow showers.

Today will be colder in the valleys, mountains and deserts due to
the cold air advection coming in from the northeast. Downslope
warming will offset the cold air advection at the coast where it
will likely be a couple degrees warmer than Friday. On Sunday the
valley, mountain and desert areas will be several degrees warmer as
the cold upper low moves east and higher pressure building over the
West Coast brings weak warm air advection.

This West Coast upper ridge will be the dominate weather feature
next week with warming each day Monday through Thursday and weak
offshore flow.

&&

.AVIATION...
221600Z...Gusty northeast winds will continue this morning in the
mountains, foothills and inland valleys. Gusts of 40 to 60 kts are
expected through 20Z, then winds will gradually diminish through
tonight. Some gusts of 30 to 40 kts can be expected on the coastal
slopes of the mountains and in the foothills through Sunday morning.
Moderate to strong up/downdrafts and LLWS will continue to impact
KONT, KSBD and KSNA through this afternoon. Otherwise, FEW-SCT
clouds at/above 8,000 feet will prevail through tonight. Isolated
-SHRA/-SHSN expected in the mountains 00-18Z Sunday.

&&

.MARINE...
A Small Craft Advisory remains in effect until 10 AM this morning
for strong and gusty northeast winds mainly between Camp Pendleton
and San Clemente Island, with gusts 25-30 knots. Winds will then
diminish over the waters this afternoon and evening. Otherwise, no
hazardous marine conditions are expected through Wednesday.

&&

.BEACHES...
A long-period west swell of 4-5 feet at 15-17 seconds will impact
the beaches starting late Monday and continuing into Wednesday. Surf
of 4-6 feet is expected, with some sets to 7 feet possible in San
Diego County Tuesday and Wednesday.

&&

.FIRE WEATHER...
Strong Santa Ana winds in southwestern San Bernardino, Orange, and
western Riverside Counties today, decreasing tonight. Lowest
relative humidities this morning of 20-30 percent will low to
between 15-20 percent this afternoon. The winds will become more
easterly tonight into Sunday and slowly diminish.

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...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 Gorgonio Pass Near Banning-
     Santa Ana Mountains and Foothills.

     Wind Advisory until 6 PM PST this evening for Orange County
     Coastal Areas-San Diego County Mountains-San Diego County
     Valleys.

     Wind Advisory until noon PST today for Coachella Valley.

PZ...Small Craft Advisory until 10 AM PST this morning 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...Schenk/Moede
FIRE WEATHER...Moede
AVIATION/MARINE...Connolly




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