487
FXUS66 KSGX 151951
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
1251 PM PDT SUN MAR 15 2026
SYNOPSIS
HIGH PRESSURE OFF THE COAST WILL CONTINUE TO PASS OVER THE REGION
AND STRENGTHEN THROUGH THE WEEK, BRINGING A LONG-DURATION AND EARLY
SEASON HEAT WAVE. PATCHY LOW CLOUDS AND FOG WILL OCCUR ONCE AGAIN
NEAR THE COAST ON MONDAY MORNING BEFORE MOSTLY CLEAR SKIES TAKE HOLD
THEREAFTER. THIS HEAT EVENT WILL ENCOMPASS TEMPERATURES UP TO 30
DEGREES ABOVE NORMAL FOR THIS TIME OF YEAR, LEADING TO MODERATE TO
HIGH HEAT RISK AND RECORD BREAKING TEMPERATURES. THE AREA OF HIGH
PRESSURE WILL BEGIN TO WEAKEN BY NEXT WEEKEND, ALLOWING FOR A
GRADUAL COOLING TREND.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
MARINE LAYER CLOUDS HAVE CLEARED OUT FROM THIS MORNING AS THE MARINE
LAYER REACHED ITS MAX DEPTH OF THE WEEK NEAR 1500-1800 FEET. AN AREA
OF HIGH PRESSURE OFF THE COAST WILL CONTINUE TO STRENGTHEN,
SUPPRESSING THE MARINE LAYER INTO TONIGHT AND MONDAY MORNING. THIS
WILL LEAVE THE CHANCE FOR LOW CLOUDS AND FOG TO RETURN CLOSER TO THE
IMMEDIATE COAST BY MONDAY MORNING. THE AREA OF HIGH PRESSURE WILL
STRENGTHEN INTO THE UPCOMING WEEK, WITH MOSTLY CLEAR SKIES EXPECTED
ACROSS SOCAL TUESDAY ONWARD.
HIGH TEMPERATURES TODAY WILL BE FAIRLY SIMILAR TO YESTERDAY ACROSS
THE REGION WITH THE GREATEST WARMING OF 3-5 DEGREES EXPECTED ACROSS
THE INLAND EMPIRE AND ORANGE COUNTY. UPPER LEVEL WINDS WILL BE
OFFSHORE ON MONDAY AND TUESDAY AS THE HIGH STRENGTHENS, WHICH WILL
CONTRIBUTE TO A WARMING TREND AND LONG-DURATION HEAT WAVE ACROSS THE
REGION. THE HIGH WILL BE CENTERED OVER OUR AREA BY TUESDAY AND
WEDNESDAY, BECOMING A VERY STRONG AND HOT AIR MASS AS MODELS DEPICT
A ~594 DM HIGH OVER THE REGION. THIS WILL BRING TEMPERATURES NEAR 20
TO 30 DEGREES ABOVE NORMAL BY THIS TIME PERIOD. TUESDAY WILL BE THE
FIRST DAY OF TRIPLE DIGIT HEAT FOR SOME PARTS OF THE INLAND EMPIRE
AND LOWER DESERTS. TEMPERATURES INCREASE SLIGHTLY ON WEDNESDAY, MOST
NOTABLY OVER THE MOUNTAINS AND DESERTS BY ANOTHER 3-5 DEGREES. 80S
WILL BE COMMON ACROSS THE MOUNTAINS OF RIV/SD COUNTIES WITH 70S AND
LOWER 80S IN THE SBD MOUNTAINS. THE MOUNTAINS WILL NOT BE ESCAPING
THE HEAT THIS WEEK, SO PLEASE LIMIT OUTDOOR RECREATION EACH
AFTERNOON IN THESE AREAS.
MODELS CONTINUE TO SHOW THE TIMING OF THE HIGH PEAKING IN STRENGTH ON
THURSDAY AND FRIDAY. THIS WILL BRING THE HOTTEST TEMPERATURES OF THE
WEEK ACROSS THE AREA AS MODELS SHOW AN UNUSUAL SUMMER-LIKE 595-597
DM HIGH OVER OUR REGION AS WE ENTER THE FIRST DAYS OF SPRING. OUR
CONFIDENCE IS MODERATE ON THE EXACT STRENGTH OF THE HIGH, WHICH WILL
DICTATE EXACTLY HOW HOT WE GET LATER THIS WEEK. THE AVERAGE HIGH IN
JULIAN IN THE SD COUNTY MTS THIS TIME OF YEAR IS 57 DEGREES BUT HAS
AROUND A 60-75% CHANCE OF SEEING HIGHS REACH 90 BY THURSDAY AND
ESPECIALLY FRIDAY. NOT ONLY RECORD TEMPERATURES FOR THE MONTH OF
MARCH ARE EXPECTED TO BREAK, BUT ALSO EVEN FOR APRIL. THE RECORD
HIGHS FOR THE MONTH OF APRIL AT INDIO AND THERMAL ARE 110 FOR BOTH
SITES, WHERE NBM INDICATES A ~70% CHANCE OF BREAKING THIS RECORD.
TRIPLE DIGIT HEAT HAS AROUND A 50-50 CHANCE OF OCCURRING ACROSS THE
INLAND SAN DIEGO VALLEYS (ALPINE, EL CAJON, POWAY, ETC.) AND
NORTHERN ORANGE COUNTY (LAKE FOREST, ANAHEIM, ETC.). TEMPERATURES
WILL LIKELY SURPASS THE 100 DEGREE MARK ACROSS THE INLAND EMPIRE ON
THURSDAY AND FRIDAY, WITH AREAS AROUND SAN BERNARDINO AND RIVERSIDE
SEEING A 50-70% CHANCE OF TEMPERATURES REACHING 105 DEGREES. MARCH
RECORD HIGHS FOR BIG BEAR (80 DEGREES) AND IDYLLWILD (82 DEGREES)
WILL LIKELY BE BROKEN DURING THIS TIME PERIOD AS WELL.
WITH MODERATE TO HIGH HEAT RISK IN THE FORECAST, PLEASE CHECK ON
FAMILY, FRIENDS, AND NEIGHBORS THIS COMING WEEK! MAKE SURE YOU HAVE
PLENTY OF WATER AND FANS TO COOL OFF IF THERE IS NO COOLING SYSTEM
OR COOLING CENTERS AVAILABLE NEAR YOU. OUTDOOR ACTIVITIES SHOULD BE
LIMITED AS THE DURATION OF THIS EARLY SEASON HEAT WAVE WILL LEAD TO
INCREASED RISK OF HEAT ILLNESS.
MODELS SHOW FAIR AGREEMENT ON THE RIDGE SLOWLY BREAKING DOWN BY NEXT
WEEKEND. THIS WILL HELP SPREAD ONSHORE FLOW AND SUBTLE COOLING FIRST
FROM THE COAST TO THE MOUNTAINS ON SATURDAY, THEN ALL AREAS BY NEXT
SUNDAY. MODELS BECOME MORE VARIED BY EARLY NEXT WEEK, BUT THE WARMER
THAN AVERAGE AND DRY WEATHER PATTERN LOOKS TO CONTINUE AS WE HEAD
TOWARD THE END OF MARCH.
AVIATION
151800Z...COASTS/WESTERN VALLEYS...LOW CLOUDS HAVE CLEARED THE
COASTAL AREAS AND HAVE GIVEN WAY TO VFR CONDITIONS THROUGH THIS
EVENING. EXPECTING PATCHIER LOW CLOUDS AROUND 300-800FT MSL TO MOVE
IN AFTER 06Z MONDAY, SPREADING UP TO 10-15 MILES INLAND. VIS
RESTRICTIONS 4-6SM WILL BE POSSIBLE MAINLY ACROSS COASTAL MESAS AND
INLAND VALLEYS. LOW CLOUDS WILL SCATTER 15-18Z.
INLAND VALLEYS/MOUNTAINS/DESERTS...BREEZY OFFSHORE WINDS ARE
DEVELOPING ON THE COASTAL MOUNTAIN SLOPES, THROUGH MOUNTAIN
PASSES, AND LOCALLY STRETCHING INTO EASTERN VALLEYS. NORTH TO
NORTHEAST WIND GUSTS OF 20-25 KTS EXPECTED, LOCALLY UP TO 35 KTS
IN MOUNTAIN PASSES. GUSTS WEAKEN AFTER 03Z MONDAY, INCREASING
AGAIN TOWARDS THE END OF THE TAF PERIOD.
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. BREAKING
WAVES OF 4-6 FEET ARE EXPECTED, 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 MONDAY 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...APR
AVIATION/MARINE...VILLAFANE
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