775
FXUS66 KSGX 122047
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
147 PM PDT THU MAR 12 2026
SYNOPSIS
UPPER LEVEL HIGH PRESSURE SYSTEM AND OFFSHORE WINDS WILL COMBINE TO
BRING HOT AND DRY CONDITIONS TO SOUTHERN CALIFORNIA TODAY AND
FRIDAY. DAILY RECORD HIGHS WILL BE BROKEN IN SEVERAL LOCATIONS. A
RETURN OF ONSHORE FLOW WILL BRING SOME COOLING TO THE COASTAL BASIN
OVER THE WEEKEND, BUT TEMPS WILL REMAIN ABOVE AVERAGE NONETHELESS.
RELIEF WILL BE SHORT LIVED AS YET ANOTHER, STRONGER RIDGE PUSHES IN
FROM THE WEST STARTING SUNDAY INTO MONDAY. THIS WILL BRING A
MODERATE TO LOCALLY MAJOR HEAT RISK FOR INLAND AREAS ALONG WITH
WIDESPREAD DAILY RECORD HIGHS NEXT WEEK.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
OFFSHORE FLOW HAS LED TO A CLOUDLESS SKY ACROSS SOUTHERN
CALIFORNIA TODAY. THIS IN COMBINATION WITH A STRONG UPPER LEVEL
HIGH PRESSURE SYSTEM HAS SET THE STAGE FOR WIDESPREAD NEAR- RECORD
HIGH TEMPERATURES AND A MINOR TO MODERATE HEAT RISK TODAY AND
TOMORROW. LACK OF MARINE LAYER INFLUENCE WILL ALLOW 850 MB
TEMPERATURES NEAR 20 DEGREES C TO MIX TO THE SURFACE, PRODUCING
TEMPERATURES IN THE 90S IN THE LOW DESERTS AND INLAND VALLEYS. 80S
EXPECTED AT THE COASTLINE AND 70S IN THE MOUNTAINS.
A SHORTWAVE TROUGH WILL PASS TO THE NORTH OVER THE WEEKEND. THIS
WILL ACT TO SOMEWHAT BREAK DOWN THE UPPER RIDGE AND BRING BACK
ONSHORE FLOW. WIND GUSTS 25-35 MPH THROUGH THE HIGH DESERT AND
ALONG DESERT SLOPES WILL LIKELY BE THE ONLY SIGN OF ITS PASSAGE IN
DESERT AND MOUNTAIN AREAS. TEMPERATURES IN THESE ZONES WILL STILL
BE NEAR RECORD HIGHS. HOWEVER, THE COASTAL BASIN WILL SEE A
NOTABLE DROP IN TEMPERATURES ON SATURDAY AS THE MARINE LAYER
RETURNS TO MODIFY THE BOUNDARY LAYER. TEMPS IN THE 80S INLAND AND
70S ALONG THE COAST WILL STILL BE ABOVE NORMAL, BUT NOT RECORD-
BREAKING. ADDITIONALLY, THERE IS A CHANCE FOR LOW CLOUDS AND FOG
TO RETURN TO COASTAL AREAS SATURDAY AND SUNDAY MORNINGS. HOWEVER,
SCATTERED HIGH CLOUD COVER MAY PREVENT THIS FROM OCCURRING.
BY LATE SUNDAY INTO MONDAY, ANOTHER RIDGE WILL BEGIN TO PUSH INTO
THE REGION FROM THE WEST. THERE IS STRONG MODEL AGREEMENT THAT THE
RIDGE AXIS WILL MOVE OVER SOUTHERN CALIFORNIA MID-NEXT WEEK WITH
500 MB HEIGHTS WELL ABOVE 590 DM. THIS WILL ALLOW FOR WIDESPREAD
RECORD-BREAKING HEAT TO RETURN FOR ALL OF SOUTHERN CALIFORNIA
THROUGH NEXT WEEK WITH THE POSSIBLE EXCEPTION OF THE COASTLINE.
FOR COASTAL AREAS, TEMPERATURES WILL BE HIGHLY DEPENDENT ON THE
DIRECTION OF THE FLOW. A SURFACE HIGH PRESSURE WILL MOVE INTO THE
PLAINS AND PARTS OF THE INTERMOUNTAIN WEST BEHIND A STORM SYSTEM
BY NEXT MONDAY. IF A STRONG ENOUGH PRESSURE GRADIENT DEVELOPS,
THEN OFFSHORE FLOW WILL RETURN TO SOUTHERN CALIFORNIA. THIS WOULD
ALLOW COASTAL AREAS TO ALSO EXPERIENCE RECORD BREAKING HEAT.
REGARDLESS, MOST OF SOUTHERN CALIFORNIA WILL REMAIN HOT AND DRY
FOR THE FORESEEABLE FUTURE. NBM PROBABILITIES OF EXCEEDING 110
DEGREES LATE NEXT WEEK ARE NEAR 40% FOR PALM SPRINGS AND 70% FOR
COACHELLA. IN THE COASTAL BASIN, PROBABILITIES OF EXCEEDING 100
DEGREES ARE 90% IN SAN BERNARDINO, 80% IN RIVERSIDE, 30% IN
ANAHEIM, AND 25% IN EL CAJON. THIS INDICATES AN INCREASED CHANCE
OF BREAKING MARCH MONTHLY RECORD HIGHS.
AVIATION
1218000Z...VFR WITH SKC-FEW250. LIGHT OFFSHORE AND NORTHERLY WINDS
FOR MOST LOCATIONS, WITH WIND GUSTS NEAR 20-30 KTS AT TIMES BELOW
PASSES IN THE INLAND EMPIRE THROUGH EARLY EVENING.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH
TUESDAY.
BEACHES
LONG PERIOD SOUTHERLY 2-3 FT SWELL AT 19-21 SECONDS WILL
CREATE ELEVATED SURF AND A HIGH RIP CURRENT RISK ALONG SOUTH AND
SOUTHWEST-FACING BEACHES THROUGH TONIGHT. SURF HEIGHTS PEAKING AT 3-
6 FEET WITH SETS TO 7 FEET.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...HEAT ADVISORY UNTIL 8 PM PDT FRIDAY FOR ORANGE COUNTY COASTAL
AREAS-ORANGE COUNTY INLAND AREAS-SAN BERNARDINO AND
RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE-SAN DIEGO COUNTY
COASTAL AREAS-SAN DIEGO COUNTY VALLEYS.
PZ...NONE.
PUBLIC...KW
AVIATION/MARINE/BEACHES...APR
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