168
FXUS66 KSGX 260457
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
857 PM PST THU DEC 25 2025
SYNOPSIS
ANOTHER ROUND OF WIDESPREAD AND HEAVIER RAIN IS EXPECTED FRIDAY.
HIGHEST PRECIPITATION FAVORED IN THE NORTHERN MOUNTAINS, WITH
LIGHTER TOTALS CLOSER TO SAN DIEGO. SHOWER ACTIVITY WEAKENS LATE
FRIDAY NIGHT, FULLY TAPERING OFF SATURDAY MORNING. DRIER AND WARMER
WEATHER EARLY NEXT WEEK WITH A SANTA ANA EVENT PEAKING MONDAY.
SHOWERS COULD RETURN FROM THE SOUTH SOME TIME THE LATTER HALF OF
NEXT WEEK CENTERED AROUND NEW YEAR'S DAY.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
TODAY PROVIDED A BREAK IN PRECIPITATION WITH MOST MODEL GUIDANCE
INDICATING SCATTERED LIGHT SHOWERS WILL BEGIN TO DEVELOP FOR SOME
LOCATIONS BY MIDNIGHT. A MORE DEFINED BAND OF RAINFALL IS EXPECTED
TO MOVE NORTHWEST TO SOUTHEAST ACROSS THE AREA TOMORROW. THERE STILL
REMAINS SOME MODEL DIFFERENCES IN TIMING, BUT LATEST GUIDANCE IS
INDICATING THE TIMING OF THE RAIN BAND ENTERING ORANGE AND WESTERN
SAN BERNARDINO COUNTIES AROUND MID-MORNING FRIDAY. RAIN WILL BE
MODERATE TO LOCALLY HEAVY WITH RAINFALL RATES OF 0.30-0.60"/HOUR.
MORE INFORMATION ON RAINFALL TOTALS AND EXPECTED SNOW AMOUNTS (FOR
ELEVATIONS 6500-7000 FT AND ABOVE)CAN BE FOUND IN THE HYDROLOGY
SECTION BELOW. IN THE WAKE OF THE MAIN RAIN BAND SCATTERED MOSTLY
LIGHT SHOWERS WILL DEVELOP. SHOWERS WILL EVENTUALLY TAPER OFF BY
LATE SATURDAY MORNING.
FROM PREVIOUS DISCUSSION ISSUED AT 2 PM 12/25...
SUNDAY THROUGH LATE WEEK...
MUCH DRIER CONDITIONS EXPECTED COME THE BEGINNING OF NEXT WEEK AFTER
THIS WEEKEND'S SYSTEM DEPARTS. HOWEVER, A POTENT INSIDE SLIDER UPPER
TROUGH HELPS TO STRENGTHEN THE OFFSHORE GRADIENT, WITH A SANTA ANA
WIND EVENT LOOKING MORE LIKELY FOR SUNDAY INTO TUESDAY. CW3E WRF
ENSEMBLE MEANS SUGGEST THIS COULD BE A MODERATE STRENGTH EVENT WITH
A ~60% CHANCE OF A MODERATE TO STRONG EVENT. GIVEN THE RECENT
RAINFALL, THERE IS NOT AS HIGH OF A FIRE CONCERN, BUT THE POTENTIAL
FOR STRONG WIND GUSTS THROUGH AND BELOW MOUNTAIN PASSES IS WORTH
NOTING. WEAK UPPER LEVEL RIDGING COINCIDING WITH THE DOWNSLOPING
OFFSHORE WINDS WILL TREND TEMPERATURES UP TO 5 TO 10 DEGREES ABOVE
NORMAL.
ATTENTION QUICKLY TURNS TO CUT-OFF LOW OUT IN THE SOUTH-CENTRAL
PACIFIC THAT COULD BRING THE NEXT SHOT OF RAIN TO SOUTHERN
CALIFORNIA. GLOBAL ENSEMBLES DIVERGE SIGNIFICANTLY ON THE RESOLUTION
OF THIS STORM SYSTEM, SO UNCERTAINTY FOR THIS EVENT IS QUITE HIGH.
KEEP AN EYE ON THE FORECAST TO SEE HOW THIS PANS OUT, BUT EARLY
INDICATIONS HINT THAT THIS WILL BE A MUCH LESS INTENSE EVENT THAN
YESTERDAY'S ATMOSPHERIC RIVER.
AVIATION
260430Z....COASTS/VALLEYS...A FEW LOW CLOUDS AROUND 1000 FT MSL OVER
SAN DIEGO COUNTY WITH ORANGE COUNTY SEEING A FEW AROUND 6000-8000 FT
MSL. LOW CLOUDS ARE EXPECTED TO INCREASE IN COVERAGE AND LOWER
BEGINNING OVER ORANGE COUNTY AFTER 07Z AND IN SAN DIEGO COUNTY AFTER
10Z TO AROUND 2500-6000 FT MSL. GUSTY SOUTHERLY WINDS UP TO 20KT ARE
POSSIBLE AS THIS NEXT SURGE OF MOISTURE MOVES THROUGH THE AREA.
MODERATE UP/DOWNDRAFTS DOWNWIND OF THE SANTA ANAS INTO THE INLAND
EMPIRE THROUGH FRIDAY MORNING.
MOUNTAINS/DESERTS
LOW CLOUDS AROUND 7000 FT MSL ARE EXPECTED TO
SLOWLY LOWER TO AROUND 1000-3000 FT MSL AFTER 10Z. WINDS ARE STILL A
BIT BREEZY OVER KONT WITH WINDS OUT OF THE WEST AROUND 7-10KTS AND
ARE EXPECTED TO STAY AROUND THOSE VALUES THROUGH THE TAF PERIOD.
REGION-WIDE
A BAND OF MODERATE TO LOCALLY HEAVY RAIN MOVES INTO
THE REGION FROM THE NORTHWEST STARTING AROUND 12-14Z, THOUGH EXACT
TIMING IS STILL A BIT UNCERTAIN, AND WILL MOVE ACROSS THE AREA
THROUGH THE DAYTIME. A FEW HOURS OF MVFR TO LOCALLY IFR CIGS/VIS ARE
EXPECTED AS THE RAIN MOVES THROUGH. SCT -SHRA IN THE WAKE OF THE
MAIN BAND WILL CREATE INTERMITTENT CIG/VIS REDUCTIONS INTO SATURDAY
NIGHT.
MARINE
SOUTH TO SOUTHWEST WINDS STRENGTHEN SLIGHTLY AGAIN LATE TONIGHT INTO
FRIDAY, WITH GUSTS INTERMITTENTLY EXCEEDING 20 KTS. WINDS WILL THEN
TURN NORTHWEST AND GRADUALLY DECREASE LATE FRIDAY INTO SATURDAY.
BEACHES
WESTERLY SWELLS WILL LEAD TO SURF BUILDING 5 TO 8 FEET FRIDAY-
SATURDAY. HIGHEST SURF IS EXPECTED FOR WEST-FACING BEACHES. A SURF
ADVISORY IS IN EFFECT NOW THROUGH SATURDAY AFTERNOON.
HYDROLOGY
MORE WIDESPREAD SHOWERS AND A MORE DEFINED BAND OF RAINFALL IS
EXPECTED TO PUSH THROUGH THE REGION FRIDAY. MAXIMUM RAINFALL RATES
WITH THIS BAND OF 0.3-0.6"/HR EXPECTED. TOTAL ADDITIONAL RAINFALL OF
1-3 INCHES (AND LOCALLY UP TO 4") FOR THE SAN BERNARDINO MOUNTAINS,
1-1.5 INCHES FOR ORANGE COUNTY AND PORTIONS OF THE INLAND EMPIRE
ADJACENT TO THE SAN BERNARDINO MOUNTAINS, WITH ABOUT 0.25-0.75" FOR
SAN DIEGO COUNTY COASTS/VALLEYS AND THE REMAINDER OF THE INLAND
EMPIRE. GIVEN THE 4-8" (LOCALLY UP TO 12") THAT FELL IN THE SAN
BERNARDINO MOUNTAINS, RESULTING IN WIDESPREAD FLASH FLOODING AND
NUMEROUS INSTANCES OF DEBRIS FLOW IN THE MOUNTAINS AND SURROUNDING
DRAINAGES, A FLOOD WATCH IS NOW IN EFFECT FOR THE SAN BERNARDINO
MOUNTAINS, HIGH DESERT, AND PORTIONS OF THE NORTHERN INLAND EMPIRE
ADJACENT TO THE MOUNTAINS FROM MIDNIGHT TONIGHT THROUGH 4PM FRIDAY
AFTERNOON.
RAINFALL WILL TREND DOWN IN INTENSITY FRIDAY AFTERNOON, BUT
ADDITIONAL LIGHT PRECIPITATION REMAINS POSSIBLE INTO SATURDAY
MORNING BEFORE CLEARING OUT COMPLETELY LATE SATURDAY MORNING. SNOW
LEVELS FELL BELOW 7000 FEET BRIEFLY TODAY, BUT RISE BACK TO 7500-
8000 FEET FOR MOST OF THE DURATION OF THE PRECIPITATION BEFORE
FALLING BACK TO NEAR 5000 FEET BY SATURDAY MORNING. 2-3 INCHES OF
SNOW IS POSSIBLE NEAR 7000 FT WITH 8-12 INCHES POSSIBLE NEAR
MOUNTAIN PEAKS.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...HIGH SURF ADVISORY UNTIL 11 AM PST SATURDAY FOR ORANGE COUNTY
COASTAL AREAS-SAN DIEGO COUNTY COASTAL AREAS.
FLOOD WATCH FROM MIDNIGHT PST TONIGHT THROUGH FRIDAY AFTERNOON
FOR APPLE AND LUCERNE VALLEYS-SAN BERNARDINO COUNTY
MOUNTAINS-SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE
INLAND EMPIRE.
PZ...NONE.
PUBLIC...CO
AVIATION/MARINE/BEACHES...VILLAFANE
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