806
FXUS66 KSGX 231745
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
945 AM PST TUE DEC 23 2025
SYNOPSIS
SCATTERED SHOWERS ARE EXPECTED TO DEVELOP TODAY. RAIN WILL BECOME
HEAVY AT TIMES LATE TONIGHT WITH HEAVY RAINFALL FROM A
STRENGTHENING ATMOSPHERIC RIVER SPREADING SOUTHWARD ACROSS THE
AREA FOR LATE TONIGHT INTO WEDNESDAY MORNING WITH THE HEAVY RAIN
CONTINUING INTO WEDNESDAY EVENING. SHOWERS WILL CONTINUE ON
THURSDAY WITH ANOTHER ROUND OF MORE WIDESPREAD SHOWERS FOR
THURSDAY NIGHT INTO FRIDAY. GUSTY SOUTH WINDS WILL DEVELOP TONIGHT
AND CONTINUE THROUGH WEDNESDAY EVENING WITH GUSTS TO 40 MPH NEAR
THE COAST AND TO 50 TO 70 MPH, LOCALLY TO 80 MPH ALONG AND BELOW
THE DESERT SLOPES OF THE SAN BERNARDINO COUNTY MOUNTAINS. SNOW
LEVELS ABOVE 9000 FEET FOR WEDNESDAY WILL FALL TO AROUND 7000 FEET
ON THURSDAY TO AROUND 5000 FEET FOR EARLY SATURDAY. DRIER WEATHER
IS EXPECTED FOR THE WEEKEND WITH HIGH TEMPERATURES AROUND 5
DEGREES BELOW AVERAGE.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
AVIATION
231800Z....A HIGH BROKEN TO OVERCAST LAYER OF CLOUDS WILL CONTINUE
TO COVER THE AREA AROUND 20-25K FT MSL THROUGH THE TAF PERIOD. LOW
CLOUDS WITH BASES 1500-5000 FT MSL EXPECTED ALONG THE COAST WITH
INLAND AREAS GETTING AS LOW AS 300-700FT MSL AFTER 12-14Z WEDNESDAY.
LIGHT RAIN CHANCES THROUGH THE DAY TODAY WITH INCREASING CHANCES
THROUGH THIS EVENING AND OVERNIGHT. VIS REDUCTIONS 1-4 SM ARE
EXPECTED AS RAIN CHANCES INCREASE. THE MAIN RAIN BAND WILL MOVE
IN FROM THE NORTHWEST TO THE SOUTHEAST TOWARDS THE END OF THE TAF
PERIOD AND WILL BRINGING MODERATE TO HEAVY PRECIPITATION WITH VIS
REDUCTIONS 1-3 SM ALONG WITH STRONG SOUTH TO SE WINDS.
MARINE
AN APPROACHING STORM SYSTEM WILL LEAD TO STRENGTHENING SOUTH TO
SOUTHEAST WINDS AND BUILDING SEAS THIS AFTERNOON. WINDS INITIALLY
AROUND 15-20 KTS GUSTING TO 25 KTS THIS AFTERNOON WILL INCREASE
EARLY WEDNESDAY TO GALE FORCE, WITH WIND GUSTS UPWARDS OF 35 KTS.
THIS WILL BRING STEEP COMBINED SEAS OF 6-9 FEET. ADDITIONALLY,
PERIODS OF MODERATE TO HEAVY RAIN WEDNESDAY WILL LEAD TO AREAS OF
POOR VISIBILITY. WINDS DIMINISH SLIGHTLY LATE WEDNESDAY THROUGH
EARLY THURSDAY, BUT WINDS AND SEAS WILL REMAIN HAZARDOUS TO SMALL
CRAFT. ANOTHER ROUND OF STRONGER SOUTHWEST WINDS EXPECTED LATE
THURSDAY INTO EARLY FRIDAY, WITH GUSTS AROUND 25 KTS. WINDS WEAKEN
AND TURN NORTHWESTERLY FRIDAY.
HYDROLOGY
SCATTERED, MOSTLY LIGHT SHOWERS ARE EXPECTED TO DEVELOP TODAY AND
CONTINUE INTO THIS EVENING. RAIN IS EXPECTED TO BECOME HEAVY AT
TIMES LATE TONIGHT ALONG THE SOUTH SLOPES OF THE SAN BERNARDINO
COUNTY MOUNTAINS WITH HEAVY RAINFALL SPREADING SOUTHWARD ACROSS
THE AREA FOR LATE TONIGHT THROUGH WEDNESDAY MORNING WITH THE HEAVY
RAINFALL CONTINUING THROUGH WEDNESDAY EVENING. SHOWERS
WILL CONTINUE ON THURSDAY WITH ANOTHER ROUND OF MORE WIDESPREAD
SHOWERS FOR THURSDAY NIGHT INTO FRIDAY. THE SNOW LEVEL WILL RISE
TO ABOVE 9000 FEET FOR EARLY WEDNESDAY MORNING, FALL TO AROUND
7000 FEET ON THURSDAY AND THURSDAY NIGHT, THEN FALL TO 4500 TO
5000 FEET FOR EARLY SATURDAY MORNING.
THROUGH WEDNESDAY NIGHT, FOR ORANGE AND SOUTHWESTERN SAN
BERNARDINO COUNTIES, RAINFALL COULD RANGE FROM 2.5 TO 3.5 INCHES
NEAR THE COAST TO 6 TO 8 INCHES ON THE COASTAL SLOPES OF THE SAN
BERNARDINO COUNTY MOUNTAINS WITH ISOLATED TOTALS TO AROUND 12
INCHES ON THE COASTAL SLOPES TO THE WEST OF THE CAJON PASS.
RAINFALL WILL DECREASE FROM NORTH TO SOUTH WITH RAINFALL ACROSS
FAR SOUTHERN SAN DIEGO COUNTY AROUND 1.5 INCH NEAR THE COAST TO
2.5 INCHES IN THE MOUNTAINS. FOR THE HIGH DESERT, 1.5 INCH TO 3.5
INCHES NEAR THE FOOTHILLS OF THE SAN GABRIEL MOUNTAINS IS
EXPECTED WITH 0.75 TO 1.5 INCH FOR THE LOWER DESERTS.
THE SAN BERNARDINO COUNTY MOUNTAINS ARE PART OF A HIGH RISK AREA
FOR EXCESSIVE RAINFALL FOR WEDNESDAY MORNING THROUGH WEDNESDAY
NIGHT, AREAS WITH A HEIGHTENED RISK FOR DAMAGING AND POTENTIALLY
LIFE-THREATENING FLASH FLOODING. HOURLY RAINFALL RATES OF AROUND
0.50 INCH ARE LIKELY FOR SEVERAL HOURS ON THE COASTAL SLOPES OF
THE EASTERN SAN GABRIEL MOUNTAINS FROM BEFORE DAWN ON WEDNESDAY
THROUGH WEDNESDAY AFTERNOON, LOCALLY TO AROUND 1 INCH PER HOUR
FROM THUNDERSTORMS OR BANDS OF HEAVIER SHOWERS.
ADDITIONAL RAINFALL DURING THE DAY ON THURSDAY FROM SHOWERS WILL
RANGE FROM AROUND 0.50 INCH NORTH TO 0.25 INCH SOUTH, LOCALLY TO
AROUND 1 INCH ON THE COASTAL SLOPES OF THE SAN BERNARDINO COUNTY
MOUNTAINS.
FOR THURSDAY NIGHT AND FRIDAY, A WEAKER ATMOSPHERIC RIVER WILL
BRING ANOTHER ROUND OF MORE WIDESPREAD SHOWERS WITH A SLIGHT
CHANCE OF THUNDERSTORMS. FOR ORANGE AND SOUTHWESTERN SAN
BERNARDINO COUNTIES, RAINFALL COULD RANGE FROM AROUND 0.75 INCH
NEAR THE COAST TO 1 TO 2 INCHES ON THE COASTAL SLOPES OF THE SAN
BERNARDINO COUNTY MOUNTAINS WITH ISOLATED TOTALS TO AROUND 3
INCHES ON THE COASTAL SLOPES TO THE WEST OF THE CAJON PASS.
RAINFALL WILL DECREASE FROM NORTH TO SOUTH WITH RAINFALL ACROSS
FAR SOUTHERN SAN DIEGO COUNTY AROUND 0.25 TO 0.50 INCH. FOR THE
HIGH DESERT, 0.25 TO 0.50 INCH IS EXPECTED WITH LESS THAN 0.25
INCH FOR THE LOWER DESERTS.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...HIGH SURF ADVISORY FROM 11 PM THIS EVENING TO 11 AM PST SATURDAY
FOR ORANGE COUNTY COASTAL AREAS-SAN DIEGO COUNTY COASTAL
AREAS.
WIND ADVISORY FROM 3 AM TO 10 PM PST WEDNESDAY FOR ORANGE COUNTY
COASTAL AREAS-ORANGE COUNTY INLAND AREAS-SAN BERNARDINO AND
RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE-SAN DIEGO COUNTY
COASTAL AREAS-SAN DIEGO COUNTY VALLEYS-SANTA ANA MOUNTAINS
AND FOOTHILLS.
FLOOD WATCH FROM LATE TONIGHT THROUGH LATE WEDNESDAY NIGHT FOR
SAN DIEGO COUNTY COASTAL AREAS-SAN DIEGO COUNTY DESERTS-SAN
DIEGO COUNTY MOUNTAINS-SAN DIEGO COUNTY VALLEYS.
FLOOD WATCH FROM THIS EVENING THROUGH WEDNESDAY EVENING FOR
APPLE AND LUCERNE VALLEYS-COACHELLA VALLEY-ORANGE COUNTY
COASTAL AREAS-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.
HIGH WIND WARNING UNTIL 3 PM PST THURSDAY FOR APPLE AND LUCERNE
VALLEYS-SAN BERNARDINO COUNTY MOUNTAINS.
PZ...GALE WARNING FROM 1 PM THIS AFTERNOON TO 4 PM PST WEDNESDAY FOR
COASTAL WATERS FROM SAN MATEO POINT TO THE MEXICAN BORDER
AND OUT TO 10 NM-WATERS FROM SAN MATEO POINT TO THE MEXICAN
BORDER EXTENDING 10 TO 60 NM OUT INCLUDING SAN CLEMENTE
ISLAND.
PUBLIC...MARTIN
AVIATION/MARINE...VILLAFANE
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