080
FXUS66 KSGX 301005
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
205 AM PST SUN NOV 30 2025
SYNOPSIS
DRY AND COOL TODAY. THE MARINE LAYER DEEPENS INTO MONDAY FOR MORE
WIDESPREAD LOW CLOUDS AND FOG EACH NIGHT AND MORNING. WEAK TO
LOCALLY MODERATE SANTA ANA WINDS DEVELOP MONDAY AND WEAKEN TUESDAY
WITH WARMER AND DRIER WEATHER. THERE IS A 15-30% CHANCE OF LIGHT
PRECIPITATION WEDNESDAY AFTERNOON INTO THURSDAY MORNING, FOLLOWED
BY ANOTHER ROUND OF WEAK TO MODERATE SANTA ANA WINDS THURSDAY INTO
FRIDAY. GRADUAL WARMING THURSDAY THROUGH THE WEEKEND WITH HIGHS
NEAR SEASONAL NORMALS.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
MORNING WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL TROUGH BEGINNING
TO DIG SOUTHEAST ACROSS THE NORTHERN GREAT BASIN AND ANOTHER UPPER
LEVEL LOW WELL OF THE SO CAL COAST. THE DIGGING TROUGH HAS ALLOWED
THE MARINE LAYER TO DEEPEN, WITH LOW CLOUDS EXTENDING INTO THE THE
INLAND SAN DIEGO COUNTY VALLEYS, THOUGH COVERAGE ACROSS ORANGE
COUNTY REMAINS SPARSE. LOCALIZED DENSE FOG IS POSSIBLE ALONG THE
INLAND EXTENT OF THE CLOUD DECK. CLOUDS WILL CLEAR BACK TO THE
COAST BY LATE MORNING WITH OTHERWISE MOSTLY CLEAR SKIES TODAY.
INCREASING ONSHORE FLOW WITH THE TROUGH PASSING BY TO THE NORTH
WILL BRING BREEZY WEST WINDS TO THE MOUNTAINS AND DESERTS,
STRONGEST THROUGH THE PASSES AND ON THE EAST FACING MOUNTAIN
SLOPES WHERE GUSTS 35-45 MPH ARE POSSIBLE THIS AFTERNOON AND
EVENING. THE PASSING TROUGH WILL ALSO RESULT IN COOLER WEATHER
WITH HIGHS NEAR SEASONAL NORMALS.
THE MARINE LAYER CONTINUES TO DEEPEN TONIGHT, POTENTIALLY
SPREADING INTO THE INLAND EMPIRE. SURFACE HIGH PRESSURE BUILDS
OVER THE GREAT BASIN TONIGHT BEHIND THE DEPARTING TROUGH, DRIVING
WEAK TO LOCALLY MODERATE SANTA ANA WINDS BY MONDAY MORNING. WINDS
PEAK DURING THE MORNING AND EARLY AFTERNOON WITH GUSTS 30-45 MPH
BELOW THE PASSES, CANYONS, AND FOOTHILLS. THESE WINDS WILL BRING
MINOR WARMING WEST OF THE MOUNTAINS WHERE HIGHS WILL BE A COUPLE
DEGREES ABOVE NORMAL, WITH COOLING IN THE MOUNTAINS AND DESERTS
DUE TO COLD AIR ADVECTION FROM THE NORTH. SURFACE PRESSURE
GRADIENTS AND WINDS WEAKEN ON TUESDAY, WITH A RETURN OF WEAK
ONSHORE FLOW BY THE AFTERNOON FOR SLIGHT COOLING WEST OF THE
MOUNTAINS AND SLIGHT WARMING IN THE MOUNTAINS AND DESERTS.
FOR THE MIDWEEK SYSTEM, ALL OF THE GLOBAL ENSEMBLES AND
DETERMINISTIC MODELS HAVE TRENDED MORE TOWARDS AN INSIDE TRACK.
BY THURSDAY, ONLY ABOUT 36% PERCENT OF THE MEMBERS MAINTAIN THE
CLOSED LOW OR DEEP TROUGH OVER SO CAL ON THURSDAY COMPARED TO 75%
FROM THE 00Z SATURDAY RUNS. THE TROUGH STILL TRACKS CLOSE ENOUGH
TO MAINTAIN A 15-30% CHANCE OF SHOWERS WEDNESDAY AFTERNOON THROUGH
THURSDAY MORNING, THOUGH WITH THE TREND TOWARDS THE MORE INSIDE
TRACK, PRECIPITATION AMOUNTS HAVE DECREASED. NBM CURRENTLY HAS
AROUND A 25% CHANCE OF 0.10" OR MORE. PRECIPITATION (ASSUMING WE
GET ANY) SHUTS OFF PRETTY QUICKLY ON THURSDAY AS ANOTHER ROUND OF
WEAK TO MODERATE SANTA ANA WINDS DEVELOP BEHIND THE TROUGH. SANTA
ANA WINDS WILL LIKELY CONTINUE INTO FRIDAY. FOR NEXT WEEKEND,
ENSEMBLE SOLUTIONS BEGIN TO DIVERGE SLIGHTLY. AROUND TWO-THRIDS OF
THE MEMBERS MAINTAIN A RIDGE JUST OFF THE WEST COAST AND DRY
NORTHWESTERLY FLOW OVER SO CAL WHICH WOULD RESULT IN WARMER
WEATHER AND PERHAPS ANOTHER ROUND OF OFFSHORE FLOW, WHILE THE
REMAINING MEMBERS BREAK THE RIDGE DOWN AND HAVE MORE ZONAL FLOW
FOR COOLER WEATHER AND MORE PERSISTENT ONSHORE FLOW.
AVIATION
300930Z....COASTS/VALLEYS...PATCHY LOW CLOUDS WITH BASES AROUND 400-
1500 FT MSL HAVE MOVED ASHORE THIS EVENING AND INTO THE SAN DIEGO
VALLEY. VISIBILITIES HAVE BEEN HIGHER THAN THE PREVIOUS
EVENING/MORNING. BASES WILL LIKELY RISE SLIGHTLY THROUGH 13Z TO
AROUND 700-1500 FT MSL, ALLOWING A 40% CHANCE FOR CIGS/FG VCNTY AT
KONT AROUND 13-18Z. CLOUDS WILL CLEAR TO THE COAST IN MOST AREAS BY
15-17Z. LOW CLOUDS WILL REDEVELOP WITH BASES OF 900-1500 FT MSL AND
MOVE ASHORE AGAIN AFTER 01Z MONDAY.
MOUNTAINS/DESERTS
VFR CONDITIONS ARE 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 18Z THROUGH SUNDAY EVENING. MODERATE
UP/DOWNDRAFTS EXPECTED IN THE VICINITY OF THE MOUNTAINS. WINDS
BECOMING OFFSHORE AND BREEZY AFTER 12Z MONDAY 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 FRIDAY.
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...SS
AVIATION/MARINE...VILLAFANE
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