850
FXUS66 KSGX 201009
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
309 AM PDT WED MAY 20 2026
SYNOPSIS
WARMING WILL CONTINUE FOR THE MOUNTAINS AND DESERTS THROUGH
THURSDAY WHILE THE COAST AND VALLEYS BEGIN TO COOL. FOR FRIDAY
THROUGH SUNDAY, NOT MUCH CHANGE IN HIGH TEMPERATURES IS EXPECTED
FOR THE MOUNTAINS AND DESERTS WHILE THE COAST AND VALLEY COOL A
FEW MORE DEGREES. COOLING WILL BEGIN TO SPREAD INLAND EARLY NEXT
WEEK AS ONSHORE FLOW STRENGTHENS. PATCHIER NIGHT AND MORNING LOW
CLOUDS NEAR THE COAST WILL INCREASE IN COVERAGE AND INLAND SPREAD
FOR FRIDAY INTO EARLY NEXT WEEK WITH LOW CLOUDS SPREADING INTO
PORTIONS OF THE INLAND VALLEYS LATE EACH NIGHT WITH LATER OR MORE
LIMITED CLEARING NEAR THE COAST EACH AFTERNOON.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
SHORT TERM (TODAY THROUGH FRIDAY)
THE HUMIDITY FOR INLAND AREAS WILL ONCE AGAIN FALL TO AROUND 10
PERCENT FOR THE DESERTS FOR THIS AFTERNOON AND 10 TO 15 PERCENT
FOR THE MOUNTAINS AND INLAND VALLEYS. HIGH TEMPERATURES WILL
CONTINUE TO WARM FOR INLAND AREAS TODAY, AS MUCH AS ANOTHER 4 TO
8 DEGREES FOR THE MOUNTAINS AND DESERTS, WHILE COASTAL AREAS COOL
A FEW DEGREES. HIGH TEMPERATURES TODAY WILL RANGE FROM AROUND 70
NEAR THE COAST TO THE MID 80S TO LOWER 90S FOR THE INLAND EMPIRE
WITH THE LOWER DESERTS IN THE MID TO UPPER 90S.
FOR THURSDAY, HIGH TEMPERATURES WILL WARM ANOTHER FEW DEGREES FOR
THE DESERTS WHILE THE COAST AND VALLEYS COOL A FEW TO AROUND 5
DEGREES. FRIDAY HIGH TEMPERATURES WILL COOL A FEW DEGREES FOR MOST
AREAS. HIGH TEMPERATURES ON FRIDAY WILL RANGE FROM THE MID TO
UPPER 60S NEAR THE COAST TO THE UPPER 70S TO MID 80S FOR THE
INLAND EMPIRE WITH THE UPPER 90S FOR THE LOWER DESERTS.
THE MOST LIKELY LOCATION FOR COASTAL LOW CLOUDS THIS MORNING IS
OVER COASTAL AREAS OF SOUTHERN SAN DIEGO COUNTY INTO THE ADJACENT
WESTERN VALLEYS. GREATER COVERAGE OF LOW CLOUDS IS EXPECTED FOR
TONIGHT INTO THURSDAY MORNING FOR COASTAL AREAS WITH THE LOW
CLOUDS SPREADING INTO THE WESTERN VALLEYS FOR THURSDAY NIGHT INTO
FRIDAY MORNING.
LONG TERM (SATURDAY THROUGH TUESDAY)
HIGH TEMPERATURES WILL CHANGE LITTLE THROUGH SUNDAY, GENERALLY A
FEW DEGREES ABOVE AVERAGE FOR THE COAST AND VALLEYS AND A FEW TO
AROUND 5 DEGREES ABOVE AVERAGE FOR THE MOUNTAINS AND DESERTS. HIGH
TEMPERATURES FOR SATURDAY AND SUNDAY WILL RANGE FROM AROUND 70
NEAR THE COAST TO THE UPPER 70S TO UPPER 80S FOR THE INLAND
EMPIRE WITH THE LOWER DESERTS AROUND 100.
FOR MONDAY AND TUESDAY, A LOW PRESSURE SYSTEM MOVING INTO THE
PACIFIC NORTHWEST WILL STRENGTHEN THE ONSHORE FLOW ACROSS SOUTHERN
CALIFORNIA. THIS WILL SPREAD COOLING INLAND WITH HIGH
TEMPERATURES ON TUESDAY A FEW DEGREES BELOW AVERAGE NEAR SEA LEVEL
TO 5 TO 10 DEGREES BELOW AVERAGE FOR THE VALLEYS AND LOWER
COASTAL SLOPES OF THE MOUNTAINS. HIGH TEMPERATURES ON TUESDAY WILL
RANGE FROM THE MID TO UPPER 60S NEAR THE COAST TO THE 70S FOR THE
INLAND EMPIRE WITH THE 90S FOR THE LOWER DESERTS.
NIGHT AND MORNING LOW CLOUDS WILL SPREAD INLAND INTO PORTIONS OF
THE INLAND VALLEYS LATE EACH NIGHT WITH SLOWER AND MORE LIMITED
AFTERNOON CLEARING NEAR THE COAST. WITH THE STRONGER ONSHORE FLOW
EARLY NEXT WEEK, SOUTHWEST TO WEST WINDS FOR THE MOUNTAINS AND
DESERTS WILL GUST TO 30 TO 40 MPH ON TUESDAY AFTERNOON AND EVENING
WITH GUSTS TO AROUND 60 MPH IN THE NORTHERN COACHELLA VALLEY
BELOW THE SAN GORGONIO PASS.
AVIATION
200930Z...COAST...AREAS OF LOW CLOUDS BASED AROUND 800-1200 FEET MSL
WILL GRADUALLY DEVELOP AND COVER MUCH OF COASTAL SAN DIEGO COUNTY
AND SOUTHERN OC THIS MORNING. VIS REDUCED 1-5SM OVER HIGHER COASTAL
TERRAIN. SCATTER OUT BY 16Z. LOW CLOUDS BASED AROUND 1000 FEET MSL
WILL REDEVELOP AFTER 06Z TONIGHT INTO THURSDAY AND COVER COASTAL
AREAS MORE UNIFORMLY.
OTHERWISE, MOSTLY CLEAR AND VFR CONDITIONS TODAY AND TONIGHT.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH SUNDAY.
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...17
AVIATION/MARINE...MM
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