847
FXUS66 KSGX 061557
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
857 AM PDT MON OCT 6 2025
SYNOPSIS
HIGH PRESSURE TO THE SOUTHEAST WILL BRING GRADUALLY WARMER DAYS
INTO WEDNESDAY. THE MARINE LAYER WILL DECREASE IN DEPTH WITH NIGHT
AND MORNING LOW CLOUDS NOT SPREADING AS FAR INTO THE VALLEYS BY
WEDNESDAY. FOR LATE THURSDAY INTO SATURDAY, MOISTURE FROM THE
REMNANTS OF HURRICANE PRISCILLA IS EXPECTED TO SPREAD INTO THE
SOUTHWESTERN CALIFORNIA WITH CHANCES FOR SHOWERS PEAKING ON FRIDAY.
LOW PRESSURE FROM THE NORTHWEST WILL BRING COOLING FOR NEXT
WEEKEND WITH HIGH TEMPERATURES AS MUCH AS 5 TO 10 DEGREES BELOW
AVERAGE FOR INLAND AREAS NEXT SUNDAY.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
PRETTY SIGNIFICANT CHANGE THIS MORNING FROM YESTERDAY'S MOSTLY
CLOUD-FREE BUT CHILLY START, WITH CLOUDS BLANKETING ORANGE AND SAN
DIEGO COASTAL AND VALLEY AREAS AND NUDGING INTO THE SOUTH AND WEST
PORTIONS OF THE INLAND EMPIRE. THICKER AREAS OF THE MARINE LAYER
IN NORTH COUNTY SD EVEN RESULTED IN SOME (VERY LIGHT) DRIZZLE
EARLIER THIS MORNING. THE CLOUD LAYER HAS PREVENTED THE EFFICIENT
RADIATIONAL COOLING THAT WAS ABLE TO OCCUR THE PAST COUPLE DAYS,
SO LOW TEMPERATURES WERE ALSO NOTICEABLY WARMER FOR THE WESTERN
HALF OF THE REGION TODAY. CLOUDS WILL BE SLOW AND GRADUAL TO
CLEAR THIS MORNING, EVENTUALLY RETREATING TO THE COAST BY THE LATE
MORNING HEADING INTO THE EARLY AFTERNOON, AND PATCHES OF LOW
CLOUDS WILL LIKELY LINGER ALONG THE IMMEDIATE COAST AND JUST
OFFSHORE THROUGH THE AFTERNOON.
AWAY FROM THE IMMEDIATE COAST AND ITS CLOUDIER CONDITIONS,
AFTERNOON HIGH TEMPERATURES WILL BE WARMER THAN YESTERDAY BY A
DEGREE OR FIVE AS HEIGHTS RISE SLIGHTLY LOCALLY WITH THE INTRUSION
OF WEAK RIDGING FROM THE EAST. EXPECT HIGH 70S NUDGING INTO THE
LOW 80S FOR VALLEYS, 80S IN THE IE AND HIGH DESERT, 60S INTO THE
LOW 70S FOR THE MOUNTAIN RIDGES, AND LOW 90S IN THE SD
DESERTS/COACHELLA VALLEY. IMMEDIATE COASTAL AREAS WILL SEE LOW
70S. THIS GRADUAL WARMING TREND CONTINUE THROUGH
WEDNESDAY/THURSDAY, BRINGING HIGH TEMPERATURES TO JUST ABOUT
AVERAGE.
THE MARINE INVERSION WILL STRENGTHEN AND LOWER SLIGHTLY
IN THE NEXT FEW DAYS, WITH MORE COASTAL LOW CLOUDS IN THE LATE
EVENING THROUGH MID- TO LATE-MORNING EACH DAY. LOW CLOUDS LOOK TO
START OUT PATCHY AGAIN THIS EVENING, BECOMING MORE
CONSISTENT/WIDESPREAD TOWARDS 9-10 PM. NOT THE BEST POSSIBLE
VIEWING CONDITIONS FOR THE SUPERMOON AT THE IMMEDIATE COAST, BUT
IT WILL VERY LIKELY BE VISIBLE MOST COASTAL AREAS IN THE EARLIER
EVENING BEFORE THE CLOUDS BUILD IN, WITH GREAT VISIBILITY FARTHER
INLAND.
LONG TERM (THURSDAY THROUGH SUNDAY)...349 AM PDT MON OCT 6
LOW PRESSURE OFF THE WEST COAST IS EXPECTED TO DIRECT MOISTURE
FROM THE REMNANTS OF HURRICANE PRISCILLA INTO THE SOUTHWESTERN
STATES. THE NHC TRACK FORECAST IS CLOSEST TO THE ENSEMBLE GUIDANCE
OF THE ECMWF. FOR LATE THURSDAY AFTERNOON THROUGH LATE SATURDAY
AFTERNOON, THE MODEL CLUSTER THAT IS WETTEST ACROSS SOUTHERN
CALIFORNIA CONTAINS MORE THAN HALF OF ECMWF ENSEMBLE MEMBERS.
DETERMINISTIC NBM OUTPUT HAS LOWER LEVEL MOISTURE PEAKING ACROSS
THE AREA DURING THE DAY ON FRIDAY. CHANCES FOR MEASURABLE RAINFALL
PEAK ON FRIDAY AT 25 TO 35 PERCENT WITH CHANCES FOR ONE INCH OR
MORE OF RAINFALL IN THE MOUNTAINS AROUND 5 PERCENT.
THE ECMWF EXTREME FORECAST INDEX SHOWS THE MOST LIKELY LOCATIONS
FOR CLIMATOLOGICALLY-UNUSUAL RAINFALL FOR THURSDAY NIGHT AND
FRIDAY EXTENDS FROM OFF THE CENTRAL COAST OF BAJA THROUGH
NORTHERN BAJA INTO THE EASTERN DESERTS OF SOUTHERN CALIFORNIA AND
INTO SOUTHWESTERN ARIZONA.
LOW PRESSURE TO THE NORTHWEST WILL BRING COOLING FOR NEXT WEEKEND
WITH HIGH TEMPERATURES FOR INLAND AREAS NEXT SUNDAY AS MUCH AS 5
TO 10 DEGREES BELOW AVERAGE.
AVIATION
061530Z....COASTS/WESTERN VALLEYS...LOW CLOUDS 700-1800 FEET MSL
HAVE MADE IT INTO PORTIONS OF THE INLAND EMPIRE. SCATTER OUT
EXPECTED THROUGH 18Z, BUT INTERMITTENT PATCHY CIGS MAY CONTINUE AT
THE COAST THEREAFTER. LOW CLOUDS WITH SIMILAR BASES MOVING INTO THE
COAST AND WESTERN VALLEYS 03-06Z TUE, THERE IS A 40% CHANCE OF CIGS
REACHING KONT 11-14Z TUE.
INLAND VALLEYS/MOUNTAINS/DESERTS...MOSTLY CLEAR AND VFR CONDITIONS
WILL CONTINUE TODAY AND TONIGHT.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH THURSDAY. FRIDAY
AFTERNOON, THERE IS A 5-10% CHANCE OF THUNDERSTORMS WITHIN 10
NAUTICAL MILES OF THE COAST.
SGX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...NONE.
PUBLIC...CSP/17
AVIATION/MARINE...CO
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