410
FXUS66 KSGX 161200
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
500 AM PDT MON MAR 16 2026
SYNOPSIS
HIGH PRESSURE WILL STRENGTHEN THIS WEEK WITH ALL-TIME RECORD HEAT
FOR MARCH FOR SOME INLAND LOCATIONS FOR THE LATTER HALF OF THIS
WEEK. THERE WILL BE WEAK OFFSHORE LOWER-LEVEL FLOW FOR TODAY WITH
NORTHERLY GUSTS TO 25 TO 35 MPH ALONG AND BELOW THE COASTAL SLOPES
OF THE MOUNTAINS AND ON TUESDAY WITH EAST TO NORTHEAST GUSTS TO
30 TO 40 MPH. SOME COOLING IS EXPECTED FOR NEXT SUNDAY AND
MONDAY, BUT WITH HIGH TEMPERATURES FOR INLAND AREAS STILL 10 TO 15
DEGREES ABOVE AVERAGE FOR MONDAY OF NEXT WEEK.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
SHORT TERM (TODAY THROUGH WEDNESDAY)
HIGH PRESSURE ALOFT OFF THE CALIFORNIA COAST WILL MOVE SLOWLY
EASTWARD THIS WEEK AND SLOWLY STRENGTHEN WITH THE STRONGEST HIGH
PRESSURE ALOFT OVER SOUTHERN CALIFORNIA CENTERED AROUND THURSDAY.
THE CURRENT RECORD FOR HIGHEST 500 MB HEIGHT FOR SAN DIEGO FOR
MARCH IS AROUND 590 DM. THE PREVIOUS EARLIEST THE 500 MB HEIGHT
FOR SAN DIEGO HAS REACHED 594 DM IS MAY 22ND. THE EARLIEST FOR 595
DM IS EARLY JUNE.
THERE WILL ALSO BE WEAK OFFSHORE LOWER-LEVEL FLOW FOR TODAY WITH
NORTH WINDS GUSTS TO 25 TO 35 MPH BELOW THE CAJON PASS AND NEAR
THE COASTAL FOOTHILLS OF THE SANTA ANA MOUNTAINS. OFFSHORE FLOW
WILL BE SLIGHTLY STRONGER ON TUESDAY WITH EAST TO NORTHEAST GUSTS
TO 30 TO 40 MPH.
THE MARINE LAYER IS AROUND 1200 FEET DEEP EARLY THIS MORNING WITH
SATELLITE IMAGERY SHOWING COASTAL LOW CLOUDS EXTENDING INLAND INTO
NORTHWESTERN ORANGE COUNTY.
THE GREATEST WARMING OF HIGH TEMPERATURES FOR TODAY, OF AROUND 8
TO 12 DEGREES, WILL BE FOR INLAND COASTAL AREAS WITH MOST AREAS
WARMING ANOTHER 4 TO 8 DEGREES ON TUESDAY. ON WEDNESDAY, A WEAK
COASTAL EDDY COULD BRING A FEW DEGREES OF COOLING FOR INLAND
COASTAL AREAS INTO THE WESTERN VALLEYS WITH THE MOUNTAINS AND
DESERTS WARMING ANOTHER FEW TO AROUND 5 DEGREES.
HIGH TEMPERATURE RECORDS FOR TODAY ARE MOST LIKELY TO BE TIED OR
BROKEN IN PORTIONS OF THE VALLEYS AND LOWER DESERTS. ON TUESDAY,
HIGH TEMPERATURES NEAR OR EXCEEDING DAILY RECORDS ARE MOST LIKELY
FOR THE MOUNTAINS, DESERTS, AND VALLEYS WITH WIDESPREAD RECORD
HIGH TEMPERATURES ON WEDNESDAY. SOME OF THOSE COULD EXCEED THE
EXISTING DAILY RECORD BY MORE THAN 5 DEGREES WITH SOME EXCEEDING
THE EXISTING MONTHLY RECORD FOR MARCH.
LONG TERM (THURSDAY THROUGH SUNDAY)
THE HEAT IS EXPECTED TO PEAK FOR MOST AREAS ON THURSDAY OR FRIDAY
WITH RECORD HIGH 500 MB HEIGHTS FOR MARCH OVER SOUTHERN
CALIFORNIA. WIDESPREAD RECORD HEAT WILL CONTINUE THROUGH SATURDAY.
WEAKENING HIGH PRESSURE ALOFT AND ONSHORE FLOW WILL BEGIN TO
SPREAD COOLING INLAND ON SUNDAY AND MONDAY, BUT WITH HIGH
TEMPERATURES FOR INLAND AREAS FOR MONDAY OF NEXT WEEK STILL 10 TO
15 DEGREES ABOVE AVERAGE.
THE CURRENTLY FORECAST LOW TEMPERATURES FOR IDYLLWILD OF 64 FOR
BOTH FRIDAY AND SATURDAY WOULD BE THE EARLIEST FOR SUCH A WARM LOW
TEMPERATURE AT IDYLLWILD BY ALMOST THREE MONTHS, THE CURRENT
EARLIEST DATE FOR SUCH A WARM LOW TEMPERATURE BEING JUNE 16TH
(2021).
&
AVIATION
160500Z...COASTS/WESTERN VALLEYS...PATCHY LOW CLOUDS 300-800FT MSL
REFORM AND MOVE IN COASTAL AREAS AFTER 08Z, MOVING 10-15 MILES
INLAND OVERNIGHT. VIS RESTRICTIONS 3-5SM WILL BE POSSIBLE MAINLY
ACROSS COASTAL MESAS AND INLAND VALLEYS. CLOUDS WILL BE MORE
PATCHWORK THAN LAST NIGHT, LEADING TO LOW TO MOD CONFIDENCE IN
INITIAL TIMING OF CIGS, AND INTERMITTENT SCATTER OUT OVERNIGHT IS
LIKELY. LOW CLOUDS CLEAR IN MOST AREAS 14-16Z, FOLLOWED BY
WIDESPREAD VFR.
INLAND VALLEYS/MOUNTAINS/DESERTS... ANOTHER PERIOD OF N/NE OFFSHORE
WINDS OVER COASTAL MOUNTAIN SLOPES, THROUGH MOUNTAIN PASSES, AND
LOCALLY STRETCHING INTO EASTERN VALLEYS AREAS 18Z MON TO 02Z TUE.
WINDS GUSTING 20-25 KTS.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH
THURSDAY.
BEACHES
A LONG PERIOD (17-19 SECOND) SOUTH-SOUTHWESTERLY SWELL (190-200
DEGREES) BUILDS TO 2-4 FEET MONDAY AFTERNOON INTO TUESDAY. THIS WILL
LEAD TO BREAKING WAVES OF 4-6 FEET, WITH SETS UP TO 7 FEET POSSIBLE
ON SOUTH-FACING BEACHES. THIS SWELL IS EXPECTED TO PERSIST INTO
WEDNESDAY, WANING WEDNESDAY NIGHT.
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 FROM 10 AM THIS MORNING TO 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.
EXTREME HEAT WATCH FROM THURSDAY MORNING THROUGH FRIDAY EVENING
FOR COACHELLA VALLEY-RIVERSIDE COUNTY MOUNTAINS-SAN
BERNARDINO COUNTY MOUNTAINS-SAN DIEGO COUNTY DESERTS-SAN
DIEGO COUNTY MOUNTAINS-SAN GORGONIO PASS NEAR BANNING.
PZ...NONE.
PUBLIC...17
AVIATION/MARINE/BEACHES...CSP
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