513
FXUS66 KSGX 291027
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
227 AM PST SAT NOV 29 2025
SYNOPSIS
COOLER AND DRY THIS WEEKEND. PATCHY FOG ALONG THE COAST THIS
MORNING, THEN INCREASING COVERAGE TONIGHT INTO SUNDAY MORNING.
WEAK SANTA ANA WINDS DEVELOP MONDAY AND WEAKEN TUESDAY FOR WARMER
AND DRIER WEATHER. THERE IS A 20-35% CHANCE OF LIGHT PRECIPITATION
WEDNESDAY INTO THURSDAY, THOUGH CONFIDENCE REMAINS LOW. ANOTHER
ROUND OF OFFSHORE WINDS WILL FOLLOW THIS SYSTEM LATE IN THE WEEK.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
PATCHY LOW CLOUDS AND FOG, WHICH HAD PUSHED INTO THE COASTAL
MESAS IN THE EVENING, HAVE ALREADY DRAINED BACK OUT TOWARDS THE
COAST, ESPECIALLY IN SAN DIEGO COUNTY. WHERE ANY FOG REMAINS OVER
THE COASTAL AREAS, VISIBILITY IS DOWN TO ONE-QUARTER MILE. VERY
WEAK OFFSHORE FLOW TO THE NORTH MAY BE ENOUGH TO KEEP COVERAGE
PATCHY THROUGH THE MORNING. OTHERWISE CLEAR WITH LIGHT WINDS THIS
MORNING. WEAK UPPER LEVEL RIDGING OFF THE COAST WILL MAINTAIN HIGH
TEMPERATURES A FEW DEGREES ABOVE NORMAL INLAND TODAY.
AN UPPER LEVEL TROUGH WILL DROP OUT OF THE PAC NW AND INTO THE
GREAT BASIN LATE TODAY INTO SUNDAY. THIS WILL BRING COOLING WITH
HIGHS RETURNING CLOSER TO SEASONAL NORMALS. GUSTY WEST WINDS WILL
ALSO DEVELOP AS ONSHORE PRESSURE GRADIENTS STRENGTHEN, WITH GUSTS
AROUND 35-45 MPH IN THE WIND PRONE PASSES AND THE DESERT SLOPES OF
THE MOUNTAINS. GRADIENTS QUICKLY TURN OFFSHORE ON MONDAY AS HIGH
PRESSURE SETTLES INTO THE GREAT BASIN BEHIND THE TROUGH. THERE
WILL BE MODEST UPPER LEVEL SUPPORT IN THE FORM OR NORTHERLY WINDS
BEHIND THE DIGGING TROUGH (850 MB WINDS OF 15-20 KT), ALBEIT
BRIEFLY. WINDS ARE CURRENTLY FORECAST TO PEAK ON MONDAY WHEN GUSTS
OF 30-45 MPH ARE LIKELY BELOW THE PASSES AND CANYONS AND INTO THE
VALLEYS, WITH ISOLATED GUSTS AROUND 50 MPH NEAR THE CAJON PASS AND
SANTA ANA MOUNTAINS. OTHERWISE WARMER WEST OF THE MOUNTAINS BUT
COOLER ELSEWHERE ON MONDAY. OFFSHORE FLOW WEAKENS AND TURNS BACK
ONSHORE ON TUESDAY AHEAD OF THE NEXT SYSTEM FOR COOLING AND
LIGHTER WINDS.
THE UPPER LEVEL PATTERN IS STILL QUESTIONABLE BEYOND WEDNESDAY
WITH THE NEXT TROUGH DROPPING DOWN FROM THE NORTH. ENSEMBLES
REMAIN INCONSISTENT WITH HOW FAR SOUTHWESTWARD THE TROUGH DIGS,
WHICH IMPACTS HOW MUCH (IF ANY) PRECIPITATION WE'LL SEE. FOR
WEDNESDAY, AROUND 58% OF THE ENSEMBLE MEMBERS BRING THE LOW FAR
ENOUGH WEST FOR AT LEAST LIGHT PRECIPITATION LATE THE EVENING. BY
THURSDAY, 32% KEEP A WEAK POSITIVELY TILTED TROUGH OVER THE AREA
(LIGHT PRECIPITATION), 25% HAVE THE TRACK INSIDE (DRY), 22%
DEVELOP A CLOSED LOW OFF THE COAST (RELATIVELY HEAVIER
PRECIPITATION), AND 21% HAVE A WEAKER LOW CLOSER TO THE COLORADO
RIVER VALLEY (LIGHTER PRECIPITATION AT THE COAST BUT HEAVIER
INLAND). EVEN INTO FRIDAY, 48% OF THE MEMBERS KEEP A CLOSED LOW
SOMEWHERE IN THE VICINITY OF SO CAL WHILE THE REMAINING 52% HAVE A
WEAKER OPEN WAVE INLAND. WITH THE CLOSED LOW SOLUTION, WE COULD
CONTINUE TO SEE COOLER WEATHER AND LIGHT PRECIPITATION IF THE LOW
IS CLOSE ENOUGH, OR WITH THE MORE PROGRESSIVE/INSIDE TRACK IT'LL
BE ANOTHER ROUND OF SANTA ANA WINDS AND WARMER AND DRIER WEATHER.
FOR WHAT IT'S WORTH, THE ECMWF AIFS ENSEMBLE, WHICH HAS BEEN
PERFORMING FAIRLY WELL, IS MUCH DRIER ON FRIDAY THAN ITS EPS AND
DETERMINISTIC COUNTERPARTS. FOR NOW JUST HAVE THE SLIGHT CHANCE TO
CHANCE (15-35%) POPS LIMITED TO WEDNESDAY MORNING THROUGH
THURSDAY EVENING, THEN SLIGHTLY WARMER AND DRY WEATHER FRIDAY AND
SATURDAY.
AVIATION
290930Z....COASTS/VALLEYS...PATCHY AREAS OF LOW CLOUDS BASED 300-700
FT MSL HAVE BEEN INTERMITTENT ALONG COASTAL REGIONS WITH VIS BETWEEN
1/4 TO 3 SM. CLOUDS HAVE SPREAD THROUGH THE COAST AND INLAND 10-15
MILES. LOW CLOUDS WILL BEGIN TO CLEAR AROUND 15-17Z FOR SAN DIEGO
COUNTY AND AROUND 17Z FOR ORANGE COUNTY. LOW CLOUDS BASED 800-1200
FT MSL WILL REDEVELOP AND MOVE ASHORE AFTER 05Z SUNDAY AND PUSH
FURTHER INLAND.
MOUNTAINS/DESERTS
VFR CONDITIONS EXPECTED THROUGH THE TAF
PERIOD.
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...SS
AVIATION/MARINE...VILLAFANE
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