763
FXUS66 KSGX 021640
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
940 AM PDT THU OCT 2 2025
SYNOPSIS
COOLER CONDITIONS WITH AN UPTICK IN WINDS IN THE MOUNTAINS AND
DESERTS FRIDAY. IN ADDITION, THE MARINE LAYER WILL DEEPEN WITH LOW
CLOUDS EXPECTED TO SPREAD INTO PORTIONS OF THE INLAND VALLEYS FOR
TONIGHT AND FRIDAY NIGHT. SLIGHTLY WARMER SATURDAY WEST OF THE
MOUNTAINS IN WEAK OFFSHORE FLOW. COOLER CONDITIONS EXPECTED SUNDAY
AND MONDAY WITH WARMING NEXT TUESDAY AND WEDNESDAY.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
TODAY IS EXPECTED TO BE 3 TO 7 DEGREES WARMER THAN YESTERDAY FOR
INLAND LOCATIONS, WITH NO CHANGE OR A DEGREE OR TWO OF COOLING ALONG
THE COAST. A TROUGH OF LOW PRESSURE IS EXPECTED TO MOVE INTO
CALIFORNIA ON FRIDAY AND EAST INTO NEVADA ON SATURDAY. THIS WILL
BRING 3 TO 5 DEGREES OF COOLING TO INLAND AREAS ON FRIDAY, WITH AN
INCREASE IN WINDS FOR THE MOUNTAINS AND DESERTS. WIND GUSTS ARE
EXPECTED TO PEAK AT 35 TO 45 MPH FRIDAY AFTERNOON AND EVENING.
ADDITIONALLY, WITH THE INCREASE IN ONSHORE FLOW THE MARINE LAYER IS
EXPECTED TO DEEPEN. AREAS OF LOW CLOUDS ARE EXPECTED TO REACH INTO
THE VALLEYS FOR TONIGHT INTO FRIDAY MORNING.
AS THE UPPER LEVEL LOW MOVES OVER NEVADA SATURDAY, THE OVERALL FLOW
WILL QUICKLY SWITCH TO OFFSHORE BY EARLY SATURDAY MORNING. THE
NORTH/NORTHEASTERLY WINDS ASSOCIATED WITH THE OFFSHORE FLOW ARE
EXPECTED TO BE FAIRLY WEAK AND LOCALIZED TO THE SAN BERNARDINO AND
SANTA ANA COASTAL MOUNTAIN SLOPES. WHILE THE MARINE LAYER WILL STILL
BE FAIRLY DEEP, ANY LOW CLOUDS THAT DEVELOP FRIDAY NIGHT INTO
SATURDAY ARE EXPECTED TO CLEAR FAIRLY QUICKLY IN THE INLAND EMPIRE
AND ORANGE COUNTY. HIGHS ON SATURDAY ARE EXPECTED TO BE A FEW
DEGREES WARMER THAN FRIDAY WEST OF THE MOUNTAINS, LIKELY DUE TO THE
WEAK OFFSHORE FLOW. TEMPERATURES IN THE DESERTS WILL CONTINUE TO
COOL A FEW DEGREES INTO SATURDAY.
A BROAD TROUGH OF LOW PRESSURE WILL SET UP OVER THE WESTERN UNITED
STATES ON SUNDAY. THIS WILL RESULT IN A FEW DEGREES OF COOLING WEST
OF THE MOUNTAINS, WITH ADDITIONAL COOLING EXPECTED INTO MONDAY FOR
MOST LOCATIONS. FOR NEXT TUESDAY AND WEDNESDAY, THE PATTERN BECOMES
A LITTLE MORE UNCERTAIN WITH ENSEMBLE GUIDANCE STRUGGLING TO PIN
DOWN THE AMPLITUDE AND POSITION OF THE AFOREMENTIONED TROUGH. THE
SOLUTION WITH A WEAKER AND DEEPER TROUGH OVER CALIFORNIA WOULD
CONTINUE THE COOLER CONDITIONS WHILE THE SOLUTION WITH THE TROUGH TO
OUR EAST WITH WEAK RIDGING OVER CALIFORNIA WOULD BRING SLIGHTLY
WARMER CONDITIONS. CURRENT FORECAST FOLLOWS THE NBM WHICH LEANS
TOWARDS THE WARMER SOLUTIONS FOR NEXT TUESDAY AND WEDNESDAY.
AVIATION
021615Z....COASTS/VALLEYS...VARIABLE LOW CLOUDS BASED 1000-1500 FEET
MSL WILL SCATTER OUT COMPLETELY WITHIN THE NEXT HOUR OR SO. LOW
CLOUDS WILL REDEVELOP AFTER 03Z FOR THE COASTAL AREAS INITIALLY, AND
AFTER 08Z INLAND TONIGHT INTO FRIDAY. BASES SHOULD BE AROUND 1500
FEET MSL, RISING OVER 2000 FEET MSL EARLY FRIDAY, FILLING MUCH OF
THE COASTAL BASIN. THEY WILL BEGIN TO SCATTER OUT BEGINNING AROUND
16-17Z FOR THE INLAND AREAS, AND THEN ERODING AWAY FROM EAST TO WEST
TO THE COASTAL AREAS BY AROUND 18-19Z SATURDAY.
MOUNTAINS/DESERTS...MOSTLY CLEAR AND VFR CONDITIONS TODAY AND
TONIGHT.
MARINE
NORTHWEST WINDS FRIDAY AFTERNOON AND EVENING OVER THE OUTER WATERS
NEAR SAN CLEMENTE ISLAND COULD LEAD TO HAZARDOUS CONDITIONS FOR
SMALL CRAFT. OTHERWISE, NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED
THROUGH MONDAY.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...NONE.
PUBLIC...CO
AVIATION/MARINE...STEWEY
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