870
FXUS66 KSGX 011654
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
854 AM PST MON DEC 1 2025
SYNOPSIS
LOW CLOUDS AND PATCHY FOG RAPIDLY CLEARING OUT THIS MORNING AS WEAK
TO LOCALLY MODERATE SANTA ANA WINDS PICK UP. OFFSHORE WINDS
WEAKEN TUESDAY FOR WARMER AND DRIER WEATHER WITH FAR LESS MARINE
LAYER CLOUD COVERAGE. CHANCES INCREASE FOR ANOTHER ROUND OF WEAK
TO MODERATE SANTA ANA WINDS LATE WEDNESDAY INTO FRIDAY, PEAKING
THURSDAY. GRADUAL WARMING THURSDAY INTO NEXT WEEKEND WITH HIGHS
NEAR SEASONAL NORMALS.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
MORNING UPDATE...
ON THE HEELS OF THE INSIDE SLIDING UPPER TROUGH NOW EJECTING INTO
THE GREAT PLAINS, A 1032 MB SURFACE HIGH PRESSURE HAS PUSHED
THROUGH THE GREAT BASIN, ESTABLISHING OUR OFFSHORE PRESSURE
GRADIENT WITH WEAK TO MODERATE SANTA ANA WINDS ALREADY IN PLACE
OBSERVED PRIMARILY THROUGH MOUNTAIN PASSES WHERE WIND GUSTS OF
30-50 MPH HAVE ALREADY OCCURRED. THE OFFSHORE FLOW HAS RESULTED
IN AN EARLY DEPARTURE OF THE MARINE LAYER, WITH A FEW LINGERING
PATCHES OF LOW CLOUDS/INLAND FOG SET TO CLEAR OUT OVER THE NEXT
HOUR OR SO.
FROM PREVIOUS DISCUSSION...
NORTHEAST TO EAST WINDS ARE FORECAST TO PEAK LATE THIS MORNING
INTO THE AFTERNOON WITH GUSTS 30-45 MPH BELOW THE PASSES, CANYONS,
AND NEAR THE FOOTHILLS, WITH ISOLATED GUSTS TO 50 MPH NEAR THE
BASE OF THE CAJON PASS. VERY WEAK RIDGING BEHIND THE DEPARTING
TROUGH AND DOWNSLOPING WINDS WILL LEAD TO WARMING WEST OF THE
MOUNTAINS, WHERE HIGHS WILL BE NEAR TO AROUND 3 DEGREES ABOVE
NORMAL, BUT COOLING ACROSS THE MOUNTAINS AND DESERTS AS COOLER AIR
MOVES IN FROM THE NORTH. SANTA ANA WINDS WEAKEN TONIGHT, TURNING
BACK ONSHORE BY TUESDAY MORNING. THIS WILL LIKELY ALLOW MARINE
LAYER LOW CLOUDS AND FOG TO RETURN TO THE COASTAL AREAS TONIGHT.
WITH THE RETURN OF ONSHORE FLOW AND A TROUGH BEGINNING TO DROP
DOWN FROM THE NORTH, TUESDAY WILL BE SLIGHTLY COOLER WITH HIGH
TEMPERATURES NEAR TO SLIGHTLY BELOW NORMAL.
MUCH LIKE THE SYSTEM TODAY, ENSEMBLES HAVE COMPLETELY TRENDED
TOWARDS AN INSIDE SLIDER TRACK WITH THE NEXT TROUGH WEDNESDAY TO
THURSDAY. WHILE SOME ENSEMBLE MEMBERS ARE STILL SHOWING VERY LIGHT
PRECIPITATION, IT WOULD BE MORE IN THE FORM OF DRIZZLE FROM A
DEEPENING MARINE LAYER WEDNESDAY MORNING. RAIN/MOUNTAIN SNOW HAVE
BEEN REMOVED FROM THE FORECAST WITH CHANCES OF MEASURABLE
PRECIPITATION NOW LESS THAN 10%. DISAPPOINTING BUT NOT SURPRISING.
ONSHORE FLOW WILL STRENGTHEN AHEAD OF THE TROUGH TUESDAY, THEN AS
IT PASSES IN AN ALMOST IDENTICAL TRACK AS THIS MORNING, ANOTHER
ROUND OF GUSTY SANTA ANA WINDS DEVELOPS BEHIND IT ON WEDNESDAY.
WINDS ARE FORECAST TO PEAK ON THURSDAY WHEN THERE IS AROUND A 30%
CHANCE OF A WEAK TO MODERATE EVENT. OFFSHORE FLOW WILL LIKELY
CONTINUE INTO AT LEAST SATURDAY MORNING, GRADUALLY WEAKENING EACH
DAY. UPPER LEVEL RIDGING SLOWLY BUILDS IN FROM THE WEST ALONG WITH
THE OFFSHORE FLOW FOR GRADUAL WARMING AND DRYING ALONG WITH MOSTLY
CLEAR SKIES FOR THURSDAY INTO EARLY NEXT WEEK WITH HIGHS WARMING
TO AS MUCH AS 5-10 DEGREES ABOVE NORMAL BY MONDAY.
AVIATION
011615Z....COASTS/VALLEYS...LOCALIZED AREAS OF LOW CLOUDS IN WESTERN
VALLEYS BASED 1800-2400 FEET MSL WITH INLAND VIS 1-5SM WILL PREVAIL
THROUGH 18Z. PATCHY LOW CLOUDS BASED AROUND 1200-1800 FEET MSL WILL
DEVELOP IN COASTAL AREAS AFTER 06Z INTO TUESDAY. OFFSHORE NORTHEAST
WINDS 20-30KTS WITH LOCALLY HIGHER GUSTS WILL CONTINUE IN FOOTHILLS
THIS MORNING AND SPREAD INTO PARTS OF INLAND VALLEYS AFTER 17Z.
THESE WILL CONTINUE THROUGH THE AFTERNOON, DIMINISHING AFTER 02Z.
OTHERWISE, MOSTLY CLEAR AND VFR CONDITIONS WILL PREVAIL TODAY AND
TONIGHT.
MOUNTAINS/DESERTS
VFR CONDITIONS THROUGH THE PERIOD. GUSTY
NORTHEAST SURFACE WINDS ON THE COASTAL SLOPES OF THE MOUNTAINS TODAY
EXCEEDING 35KTS AT TIMES. MOD UP/DOWN DRAFTS POSSIBLE IN THE
VICINITY OF THE MOUNTAIN PEAKS. LOCALIZED AREAS OF BLDU POSSIBLE.
WINDS DIMINISH AFTER 06Z TUE.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED TODAY THROUGH FRIDAY.
SGX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...NONE.
PUBLIC...MUNYAN
AVIATION/MARINE...ZUBER
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