683
FXUS66 KSGX 121250
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
550 AM PDT TUE MAY 12 2026
SYNOPSIS
THROUGH WEDNESDAY, A WEAK LOW PRESSURE SYSTEM MOVING INTO SOUTHERN
CALIFORNIA WILL DEEPEN THE MARINE LAYER TO AROUND 3000 FEET WITH
NIGHT AND MORNING COASTAL LOW CLOUDS SPREADING FARTHER INTO THE
VALLEYS AND WITH SLOWER AFTERNOON CLEARING FOR SAN DIEGO COUNTY
COASTAL AREAS. IT WILL BE SLIGHTLY WARMER FOR THURSDAY AND FRIDAY
WITH THE MARINE LAYER DECREASING IN DEPTH, THEN SLIGHTLY COOLER
FOR THE WEEKEND.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
SHORT TERM (TODAY THROUGH THURSDAY)
A WEAK LOW PRESSURE SYSTEM WILL MOVE TOWARD THE SOUTHERN
CALIFORNIA COAST TODAY AND MOVE INLAND THROUGH SOUTHERN CALIFORNIA
ON WEDNESDAY. THE MARINE LAYER BECAME SHALLOWER ON MONDAY,
DECREASING IN DEPTH TO AROUND 1500 FEET. SATELLITE IMAGERY AFTER
MIDNIGHT SHOWS WIDESPREAD LOW CLOUDS OVER THE COASTAL WATERS
SPREADING INTO THE WESTERN HALF OF THE VALLEYS IN SAN DIEGO COUNTY
AND SPREADING NORTHWARD AND INLAND ACROSS THE ORANGE COUNTY
COASTAL PLAIN. THE MARINE LAYER IS EXPECTED TO BE BEGIN DEEPENING
BEFORE SUNRISE WITH DEEPENING TO AROUND 3000 FEET FOR LATE TONIGHT
INTO WEDNESDAY MORNING. THE COASTAL LOW CLOUDS ARE EXPECTED TO
SPREAD INTO PORTIONS OF THE INLAND VALLEYS EARLY THIS MORNING,
THEN INLAND ACROSS MOST OF THE COAST AND VALLEYS FOR TONIGHT INTO
WEDNESDAY MORNING.
HIGH TEMPERATURES FOR TODAY WILL COOL AS MUCH AS 15 TO 20 DEGREES
FOR PORTIONS OF THE INLAND VALLEYS AND AS MUCH AS ANOTHER 8 TO 12
DEGREES ON WEDNESDAY FOR THE MOUNTAINS AND HIGH DESERT. HIGH
TEMPERATURES ON WEDNESDAY WILL BE A FEW TO AROUND 5 DEGREES BELOW
AVERAGE FOR THE COAST AND VALLEYS AND AROUND 5 DEGREES ABOVE
AVERAGE FOR THE LOWER DESERTS. HIGH TEMPERATURES ON WEDNESDAY WILL
RANGE FROM THE MID TO UPPER 60S NEAR THE COAST TO THE MID 70S TO
LOWER 80S FOR THE INLAND EMPIRE WITH THE LOWER DESERTS IN THE
UPPER 90S TO 103. HIGH TEMPERATURES ON THURSDAY WILL BE A FEW
DEGREES WARMER WITH THE MARINE LAYER BEGINNING TO DECREASE IN
DEPTH.
LONG TERM (FRIDAY THROUGH MONDAY)
HIGH TEMPERATURES FOR THE MOUNTAINS AND DESERTS WILL WARM ANOTHER
FEW DEGREES ON FRIDAY. HIGH TEMPERATURES ON FRIDAY WILL BE AS MUCH
AS 10 DEGREES ABOVE AVERAGE FOR THE DESERTS, REACHING 102 TO 106
FOR THE LOWER DESERTS. HIGH TEMPERATURES FOR INLAND AREAS WILL
COOL A FEW DEGREES ON SATURDAY AND ANOTHER FEW DEGREES ON SUNDAY
WITH SUNDAY HIGH TEMPERATURES A FEW TO AROUND 5 DEGREES ABOVE
AVERAGE FOR MOST AREAS. HIGH TEMPERATURES ON SUNDAY WILL RANGE
FROM AROUND 70 NEAR THE COAST TO THE UPPER 70S TO MID 80S FOR THE
INLAND EMPIRE WITH THE LOWER DESERTS IN THE MID 90S TO AROUND 100.
HIGH TEMPERATURES ON MONDAY WILL WARM A FEW TO AROUND 5 DEGREES.
120930Z...COAST/VALLEYS...LOW CLOUDS BASED 600-900 FEET MSL AND TOPS
TO 1600 FEET WILL CONTINUE OVER COASTAL AREAS AND SPREAD LOCALLY
INTO INLAND VALLEYS THIS MORNING. VIS REDUCED 0-5SM MAINLY ALONG
HIGHER COASTAL AND VALLEY TERRAIN. SCATTER OUT NOT REALLY EXPECTED
NEAR THE COAST, BUT 17-20Z INLAND. WHERE CIGS PERSIST, THEY WILL
LIFT DURING THE DAY TO 1500-2500 FEET MSL. THESE LIFTED LOW CLOUDS
WILL SPREAD INLAND AFTER 01Z, AND RAPIDLY FILL THE ENTIRE COASTAL
BASIN TO THE FOOTHILLS OVERNIGHT INTO WEDNESDAY. VIS REDUCED 0-5SM
OVER HIGHER VALLEY TERRAIN AND FOOTHILLS AND IN PATCHY -DZ.
OTHERWISE...SCT HIGH CLOUDS AND VFR CONDITIONS TODAY AND TONIGHT.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH SATURDAY.
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
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page