679
FXUS66 KSGX 170925
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
225 AM PDT TUE MAR 17 2026
SYNOPSIS
HIGH PRESSURE WILL STRENGTHEN THIS WEEK WITH ALL-TIME RECORD
STRONG HIGH PRESSURE FOR MARCH FOR MOST OF THE SOUTHWEST STATES
AND SURROUNDING AREAS FOR THE LATTER HALF OF THE WEEK WILL ALL-
TIME RECORD HEAT FOR MARCH FOR INLAND AREAS. THERE WILL BE WEAK
OFFSHORE FLOW TODAY WITH EAST TO NORTHEAST WINDS GUSTING TO 30 TO
40 MPH ALONG AND BELOW THE COASTAL SLOPES OF THE MOUNTAINS. FOR
SUNDAY INTO EARLY NEXT WEEK, WEAKENING HIGH PRESSURE ALOFT AND
ONSHORE FLOW WILL ALLOW COOLING TO SPREAD INLAND, BUT WITH HIGH
TEMPERATURES REMAINING WELL ABOVE AVERAGE, AS MUCH AS 10 TO 15
DEGREES ABOVE AVERAGE THROUGH TUESDAY OF NEXT WEEK FOR INLAND
AREAS.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
SHORT TERM (TODAY THROUGH THURSDAY)
HIGH PRESSURE WILL CONTINUE TO STRENGTHEN THE NEXT FEW DAYS WITH
THE STRONGEST HIGH PRESSURE ON RECORD FOR MARCH EXPECTED DURING
THE LATTER PART OF THIS WEEK FOR LARGE AREA CENTERED ON THE
SOUTHWEST STATES. A SHALLOW MARINE LAYER IS EXPECTED TO MODERATE
THE HEAT NEAR THE COAST. HOWEVER, RECORD HEAT WILL CONTINUE FOR
INLAND AREAS INTO NEXT WEEK. A LARGE NUMBER OF DAILY HEAT RECORDS
ARE EXPECTED TO BE TIED OF BROKEN FOR INLAND AREAS, BOTH FOR HIGH
TEMPERATURES AND FOR RECORD WARM LOW TEMPERATURES. FOR SOME
LOCATIONS, RECORDS FOR THE MONTH OF MARCH WILL BE BROKE AND NOT
NECESSARILY BY SMALL MARGINS. WIDESPREAD MODERATE OR GREATER HEAT
RISK WILL CONTINUE INTO THE WEEKEND EXCEPT NEAR THE COAST AND FOR
HIGH ELEVATIONS OF THE MOUNTAINS, MOSTLY ABOVE 6500 FEET.
ON THURSDAY, HIGH TEMPERATURES FOR THE INLAND VALLEYS AND LOWER
ELEVATIONS OF THE MOUNTAINS WILL BE AS MUCH AS 30 TO 35 DEGREES
ABOVE AVERAGE. THURSDAY HIGH TEMPERATURES WILL RANGE FROM AROUND
80 NEAR THE COAST TO THE UPPER 90S TO 103 FOR THE INLAND VALLEYS
WITH THE LOWER DESERTS REACHING 105 TO 110.
LONG TERM (FRIDAY THROUGH MONDAY)
RECORD HEAT WILL CONTINUE INTO THE WEEKEND WITH ALL-TIME RECORD
HEAT FOR MARCH FOR INLAND AREAS CONTINUING THROUGH AT LEAST FRIDAY.
FOR SUNDAY INTO EARLY NEXT WEEK, ONSHORE FLOW AND WEAKENING HIGH
PRESSURE WILL BEGIN TO SPREAD COOLING INLAND, BUT WITH HIGH
TEMPERATURES FOR INLAND AREAS STILL 10 TO 15 DEGREES ABOVE AVERAGE
FOR EARLY NEXT WEEK. FOR EARLY NEXT WEEK, FAR FEWER RECORDS FOR
HEAT WILL BE TIED OR BROKEN, MOSTLY JUST DAILY RECORDS AND BY
SMALLER MARGINS.
AVIATION
170930Z...MOSTLY CLEAR SKIES TODAY AND TONIGHT. ISOLATED LOW CLOUDS
AND FOG NEAR THE COAST THROUGH 16Z AND AGAIN AFTER 05Z TONIGHT INTO
WEDNESDAY, MOST LIKELY NEAR KSAN. LOW CONFIDENCE OF CIGS AND REDUCED
VIS AT COASTAL AIRPORTS. EAST TO NORTHEAST WINDS GUSTING 25-30 KNOTS
IN FOOTHILLS THROUGH 20Z.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH
SATURDAY.
BEACHES
A LONG PERIOD (17-19 SECOND) SOUTH-SOUTHWESTERLY SWELL (190-200
DEGREES) WILL CONTINUE TODAY, BRINGING OCCASIONAL SURF SETS UP TO 6
FEET IN ORANGE COUNTY, BEFORE GRADUALLY DECREASING WEDNESDAY.
LOCALLY HAZARDOUS SWIMMING CONDITIONS ARE EXPECTED. A BEACH HAZARDS
STATEMENT CONTAINS MORE DETAILS.
CLIMATE
HIGH PRESSURE WILL CONTINUE TO STRENGTHEN INTO THURSDAY OR FRIDAY
WITH THE SOUTHWEST STATES AND A LARGE SURROUNDING AREA HAVING THE
STRONGEST HIGH PRESSURE ON RECORD FOR MARCH FOR DATA THAT GOES
BACK TO THE EARLY 1950S. CLIMATOLOGICALLY, THE STRONGEST HIGH
PRESSURE ALOFT FOR SOUTHERN CALIFORNIA AS MEASURED BY 500 MB
HEIGHTS OCCURS DURING LATE JULY. THE HIGH PRESSURE ALOFT EXPECTED
OVER SAN DIEGO COUNTY LATE THIS WEEK WOULD BE COMPARABLE TO THE 8
TO 10 PERCENT OF HIGHEST 500 MB HEIGHTS DURING LATE JULY.
SEVERAL INLAND LOCATIONS ARE EXPECTED TO BREAK RECORDS FOR MARCH
AND FOR JANUARY THROUGH MARCH FOR BOTH HIGH TEMPERATURES AND FOR
RECORD WARM LOW TEMPERATURES.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...BEACH HAZARDS STATEMENT THROUGH WEDNESDAY EVENING FOR ORANGE
COUNTY COASTAL AREAS-SAN DIEGO COUNTY COASTAL AREAS.
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-SANTA ANA MOUNTAINS
AND FOOTHILLS.
HEAT ADVISORY FROM 10 AM WEDNESDAY TO 8 PM PDT FRIDAY FOR
RIVERSIDE COUNTY MOUNTAINS-SAN BERNARDINO COUNTY MOUNTAINS-
SAN DIEGO COUNTY MOUNTAINS.
EXTREME HEAT WARNING FROM 10 AM WEDNESDAY TO 8 PM PDT SATURDAY
FOR COACHELLA VALLEY-SAN DIEGO COUNTY DESERTS-SAN GORGONIO
PASS NEAR BANNING.
PZ...NONE.
PUBLIC/CLIMATE...17
AVIATION/MARINE/BEACHES...MM
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