166
FXUS66 KSGX 221040
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
340 AM PDT WED OCT 22 2025
SYNOPSIS
TODAY WILL BE AS MUCH AS 12 TO 18 DEGREES COOLER THAN TUESDAY FOR
THE MOUNTAINS AND INLAND VALLEYS WITH SOUTHWEST WINDS GUSTING TO
35 TO 45 MPH ALONG AND BELOW THE EAST SLOPES OF THE MOUNTAINS FOR
THIS AFTERNOON AND EVENING. THE MARINE LAYER WILL DEEPEN ONTO THE
LOWER COASTAL SLOPES OF THE MOUNTAINS THROUGH TONIGHT. DRY WITH
WARMING FOR THURSDAY AND FRIDAY, THEN COOLER AND BREEZY FOR THE
WEEKEND WITH A DEEPENING MARINE LAYER. THEN DRY AND WARMER FOR
MONDAY THROUGH WEDNESDAY OF NEXT WEEK WITH HIGH TEMPERATURES
WARMING TO AROUND 5 DEGREES ABOVE AVERAGE FOR INLAND AREAS.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
SHORT TERM (TODAY THROUGH FRIDAY)
A LOW PRESSURE SYSTEM CENTERED JUST WEST OF POINT CONCEPTION EARLY
THIS MORNING WILL MOVE INLAND THROUGH CENTRAL AND SOUTHERN
CALIFORNIA TODAY INTO THIS EVENING. THE ELEVATED CONVECTION TO
THE NORTH AND EAST OF THE LOW PRESSURE CENTER WILL MOVE EAST OF
THE AREA THIS MORNING.
THIS CONVECTION HAS PRODUCED SOME LIGHTNING AND LITTLE RAINFALL,
MOSTLY ACROSS PORTIONS OF SAN BERNARDINO AND RIVERSIDE COUNTIES
WITH ANY MEASURABLE RAINFALL A FEW HUNDREDTHS OF AN INCH. THE
MARINE LAYER HAS DEEPENED TO AROUND 2500 FEET AND WILL CONTINUE TO
DEEPEN TONIGHT TO AROUND 4000 TO 4500 FEET WITH NIGHT AND MORNING
COASTAL LOW CLOUDS EXTENDING INLAND ACROSS OF THE VALLEYS AND
ONTO THE LOWER COASTAL SLOPES OF THE MOUNTAINS FOR TONIGHT INTO
EARLY THURSDAY MORNING.
TODAY WILL BE MUCH COOLER FOR INLAND AREAS WITH HIGH TEMPERATURES
FOR THE MOUNTAINS AND INLAND VALLEYS AS MUCH AS 12 TO 18 DEGREES
COOLER THAN TUESDAY. HIGH TEMPERATURES FOR TODAY WILL BE AS MUCH
AS 5 TO 10 DEGREES BELOW AVERAGE FOR THE MOUNTAINS AND VALLEYS
WITH HIGH TEMPERATURES RANGING FROM THE UPPER 60S NEAR THE COAST
TO THE LOWER TO MID 70S FOR THE INLAND EMPIRE WITH THE 80S FOR THE
LOWER DESERTS. SOUTHWEST WINDS WILL GUST TO 35 TO 45 MPH ALONG AND
BELOW THE EAST SLOPES OF THE MOUNTAINS FOR THIS AFTERNOON AND
EVENING.
THERE WILL BE WARMING WITH WEAKER WINDS FOR THURSDAY AND FRIDAY
WITH FRIDAY HIGH TEMPERATURES AROUND 5 DEGREES ABOVE AVERAGE
FOR INLAND AREAS, RANGING FROM THE LOWER TO MID 70S NEAR THE COAST
TO THE MID TO UPPER 80S FOR THE INLAND EMPIRE WITH THE LOWER TO
MID 90S FOR THE LOWER DESERTS.
LONG TERM (SATURDAY THROUGH TUESDAY)
A LOW PRESSURE SYSTEM TO THE NORTH WILL STRENGTHEN THE ONSHORE
FLOW ACROSS SOUTHERN CALIFORNIA FOR THE WEEKEND. THIS WILL DEEPEN
THE MARINE LAYER WITH COASTAL LOW CLOUDS SPREADING INTO PORTIONS
OF THE INLAND VALLEYS BY SUNDAY WITH PERIODS OF GUSTY SOUTHWEST TO
WEST WINDS FOR THE MOUNTAINS AND DESERTS. THERE WILL BE COOLING
FOR SATURDAY AND SUNDAY WITH SUNDAY HIGH TEMPERATURES MOSTLY A FEW
TO AROUND 5 DEGREES BELOW AVERAGE, RANGING FROM AROUND 70 NEAR THE
COAST TO THE MID TO UPPER 70S FOR THE INLAND EMPIRE WITH THE MID
TO UPPER 80S FOR THE LOWER DESERTS.
MONDAY AND TUESDAY WILL BE DRY WITH WARMING WITH TUESDAY HIGH
TEMPERATURES SLIGHTLY BELOW AVERAGE FOR THE MOUNTAINS AND DESERTS
AND AS MUCH AS 4 TO 8 DEGREES ABOVE AVERAGE FOR THE WESTERN
VALLEYS AND INLAND COASTAL AREAS. HIGH TEMPERATURES ON TUESDAY
WILL RANGE FROM THE 70S NEAR THE COAST TO THE 80S FOR THE VALLEYS
WITH THE MID TO UPPER 80S FOR THE LOWER DESERTS. THERE COULD BE
WEAK OFFSHORE FLOW FOR TUESDAY AND WEDNESDAY WITH LOCALLY GUSTY
NORTHEAST TO EAST WINDS ALONG AND BELOW THE COASTAL SLOPES OF THE
MOUNTAINS.
AVIATION
220930Z...COAST/VALLEYS...LOW CLOUDS BASED 1500-2000 FEET MSL AND
VIS FAR INLAND AND HIGHER TERRAIN 2-5SM WILL EVENTUALLY COVER
MOST OF THE COASTAL BASIN BY 14Z. BASES WILL RISE TO ABOVE 2000
FEET MSL AFTER 13Z. SCATTER OUT 17-19Z. LOW CLOUDS BASED AROUND
2500-3000 FEET MSL WILL RANDOMLY AND GRADUALLY RETURN AFTER 00Z
AND COVER MOST OF THE COASTAL BASIN INTO FOOTHILLS BY EARLY
THURSDAY.
MOUNTAINS/DESERTS...SCT-BKN CLOUDS ABOVE 12000 FEET MSL WILL MOVE
EAST OUT OF THE AREA BY 15Z. WESTERLY WINDS WILL STRENGTHEN THIS
MORNING WITH STRONGEST GUSTS 35-45 KTS THROUGH MOUNTAIN PASSES AND
ON DESERT SLOPES. STRONG UP/DOWNDRAFTS AND LOCAL LLWS IN LEE OF
MOUNTAINS, SUCH AS VCNTY KPSP.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH SUNDAY.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...WIND ADVISORY FROM NOON TODAY TO MIDNIGHT PDT TONIGHT FOR SAN
DIEGO COUNTY DESERTS-SAN GORGONIO PASS NEAR BANNING.
PZ...NONE.
PUBLIC...17
AVIATION/MARINE...MM
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