352
FXUS66 KSGX 300544
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
944 PM PST SAT NOV 29 2025
SYNOPSIS
DRY AND COOLER THIS WEEKEND. PATCHY FOG ALONG THE COASTAL AREAS
AND COASTAL MESAS AGAIN TONIGHT. WEAK TO LOCALLY MODERATE SANTA
ANA WINDS DEVELOP MONDAY AND WEAKEN TUESDAY WITH WARMER AND DRIER
WEATHER. 20-35% CHANCE OF LIGHT PRECIPITATION WEDNESDAY INTO
THURSDAY, THOUGH CONFIDENCE REMAINS VERY LOW. ANOTHER ROUND OF
OFFSHORE WINDS LIKE FOLLOW THIS SYSTEM FOR THE LATE WEEK.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
SFC PRESSURE GRADIENTS REMAIN WEAKLY OFFSHORE THIS EVENING, WITH -0.1
MB SAN-DAG AND WEAK DIURNAL SLOPE WINDS. THE MARINE LAYER IS A LITTLE
DEEPER THAN AT THIS TIME YESTERDAY BUT LOW CLOUDS ARE A LITTLE
SLOWER TO FORM THAN YESTERDAY.
FROM PREVIOUS DISCUSSION...
THE NEXT SHORTWAVE TROUGH IS SET TO MOVE INTO THE GREAT BASIN FROM
THE PAC NW TONIGHT INTO SUNDAY, BRINGING STRONGER ONSHORE WINDS
SUNDAY AFTERNOON, MAINLY FOR THE HIGHER ELEVATIONS IN THE
MOUNTAINS AND ADJACENT DESERT SLOPES. WIND GUSTS 25-35 MPH
EXPECTED IN THE HIGH DESERTS/DESERT SLOPES WITH ABOUT 35-45 MPH
NEAR MOUNTAIN PEAKS. THE MARINE LAYER WILL LIKELY BE LESS PATCHY
TONIGHT, WITH CLOUD COVER STRETCHING INTO PORTIONS OF THE WESTERN
INLAND VALLEYS. AS COLD AIR SPILLS INTO THE GREAT BASIN BEHIND
THIS UPPER TROUGH, THE OFFSHORE PRESSURE GRADIENT IS EXPECTED TO
STRENGTHEN ON MONDAY, MORE THAN WHAT IS SEEN TODAY. THIS SANTA ANA
WIND EVENT WILL LIKELY BE WEAK TO MODERATE STRENGTH WITH
STRONGEST WIND GUSTS MONDAY AFTERNOON FOUND IN AND JUST BELOW
CAJON/BANNING PASS AND FREMONT CANYON UP TO 45-50 MPH, WITH 25-35
MPH GUSTS SPREADING INTO THE INLAND EMPIRE AND INLAND VALLEYS OF
SAN DIEGO AND ORANGE COUNTIES. AS FOR TEMPERATURES, SUNDAY WILL
LIKELY BE A FEW DEGREES COOLER THAN TODAY WITH THE ONSHORE FLOW,
FOLLOWED BY WARMING AND DRYING ON MONDAY WITH THE OFFSHORE FLOW.
TUESDAY INTO LATE WEEK...
ONSHORE FLOW IS QUICKLY REESTABLISHED TUESDAY AFTERNOON, RETURNING
TEMPERATURES BACK TO NEAR AVERAGE. BEYOND TUESDAY, THE UPPER
LEVEL PATTERN REMAINS QUITE UNCERTAIN THROUGH MID TO LATE WEEK AS
MODELS CONTINUE TO DISAGREE ON THE EVOLUTION OF THE NEXT TROUGH,
SET TO MOVE SOUTHWARD ON WEDNESDAY. THE GFS AND ITS ENSEMBLES
HAVE A WEAKER, SHALLOWER, AND FASTER TROUGH, WHILE THE ECMWF AND
ITS ENSEMBLES FEATURE A DEEPER AND SLOWER SYSTEM. WHILE THIS
DISAGREEMENT PERSISTS, CONFIDENCE ON ANY PRECIPITATION, BOTH
TIMING AND AMOUNTS, WILL BE LOW. IN A SCENARIO LIKE THE GFS'S,
PRECIPITATION AMOUNTS WILL BE VERY LOW, LIKELY 0.1" OR LESS, WITH
NORTHERLY OFFSHORE FLOW BUILDING WEDNESDAY INTO THURSDAY. IF THE
ECMWF'S SOLUTION WERE TO VERIFY, PRECIPITATION AMOUNTS COULD BE
CLOSER TO 0.25-0.5+" WITH RAIN CHANCES STRETCHING INTO THURSDAY,
DELAYING NORTHERLY OFFSHORE FLOW INTO LATE THURSDAY INTO FRIDAY.
UNCERTAINTY IN SNOW LEVELS EXISTS AS WELL, BUT WILL GENERALLY BE
FALLING TO AROUND 6500-6000FT WED-THURS. EITHER WAY, THIS STORM
SYSTEM ISN'T EXPECTED TO BE AN EFFICIENT RAIN MAKER, BUT STAY
TUNED OVER THE NEXT FEW DAYS TO SEE HOW THIS EVOLVES. STILL,
TEMPERATURES ARE LIKELY TO COOL BELOW AVERAGE WED-THURS WITH THE
TROUGH/CLOUD COVER, THOUGH WITH THE POTENTIAL FOR OFFSHORE FLOW,
ITS A BIT TOO EARLY TO SAY FOR SURE.
AVIATION
300400Z....COASTS/VALLEYS...PATCHY LOW CLOUDS WITH BASES AROUND
400-700FT MSL HAVE DEVELOPED OFFSHORE THIS EVENING, MOVING ASHORE
AFTER 05Z THIS EVENING AND INTO WESTERN VALLEYS OVERNIGHT. EXPECTING
VIS TO BE HIGHER TONIGHT THAN THIS MORNING, BUT THERE IS THE
POTENTIAL FOR VIS TO FALL TO 1/2 SM OR LOWER EARLIER IN THE NIGHT,
ESPECIALLY FOR HIGHER COASTAL TERRAIN. BASES WILL LIKELY RISE
SLIGHTLY OVERNIGHT TOWARDS 10-13Z, POSSIBLY TO 700-1500 FT MSL WITH
A WEAK COASTAL EDDY. DUE TO THIS, THERE IS A 30% CHANCE FOR
CIGS/FG VCNTY KONT 13-18Z. CLOUDS CLEARING TO THE COAST IN MOST
AREAS BY 15-17Z, REDEVELOP AT 900-1500 FT MSL AND MOVE ASHORE AGAIN
AFTER 00Z MON.
MOUNTAINS/DESERTS
VFR CONDITIONS EXPECTED THROUGH THE TAF
PERIOD. STRONG SURFACE WINDS GUSTING 25-35 KT, UP TO 45 KT THROUGH
WIND-PRONE PASSES, AT TIMES IN THE DESERTS AND EASTERN MOUNTAIN
SLOPES, GENERALLY AFTER 16Z THROUGH SUNDAY EVENING. MOD
UP/DOWNDRAFTS EXPECTED IN THE VICINITY OF THE MOUNTAINS. WINDS
BECOMING OFFSHORE AND BREEZY EARLY MON MORNING FOR THE WEST MTN
FOOTHILLS LOCALLY INTO EASTERN VALLEYS, WITH LOCAL AREAS OF LLWS
POSSIBLE FOR PARTS OF THE VALLEYS.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH THURSDAY.
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...PG
AVIATION/MARINE...CSP
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