357
FXUS66 KSGX 120403
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
903 PM PDT MON MAY 11 2026
SYNOPSIS
TODAY WAS THE HOTTEST DAY OF THE WEEK SO FAR BUT A COOLING TREND
IS EXPECTED FOR TUESDAY THROUGH THURSDAY. NIGHT AND MORNING LOW
CLOUDS AND FOG WILL BE PRESENT EACH DAY THROUGH THE FORECAST
PERIOD ALONG THE COAST AND INTO PORTIONS OF THE VALLEYS. A GRADUAL
WARMING EXPECTED FOR THE END OF THE WEEK.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
TODAY WAS THE WARMEST DAY OF THE WEEK SO FAR WITH A COUPLE OF
LOCATIONS IN SAN DIEGO COUNTY SETTING RECORDS (SEE THE RERSGX
PRODUCT). MANY LOCATIONS IN THE INLAND VALLEYS REACHED TEMPERATURES
IN THE UPPER 90S, AND IN THE LOW DESERTS, TEMPERATURES REACHED AS
HIGH AS 111 DEGREES AT INDIO. THIS EVENING, THE MARINE LAYER IS A
LITTLE LOWER THAN LAST NIGHT BUT ONSHORE FLOW HAS ALREADY PUSHED
LOW CLOUDS A FEW MILES INLAND IN COASTAL SAN DIEGO COUNTY.
FROM PREVIOUS DISCUSSION...
HIGH TEMPERATURES TUESDAY FOR INLAND LOCATIONS WILL FALL 6 TO 12
DEGREES FROM THEIR PEAK TODAY AS A SHORTWAVE TROUGH WEAKENS AND
PUSHES THE UPPER LEVEL RIDGE TO OUR EAST.
GUIDANCE IS IN GOOD AGREEMENT THAT A WEAK TROUGHING PATTERN WILL
PREVAIL OVER THE US WEST COAST TUESDAY THROUGH THURSDAY. THIS WILL
MAINTAIN MARINE LAYER LOW CLOUDS AND FOG FOR THE COAST AND VALLEYS
AND TAKE HIGH TEMPERATURES BACK TO WITHIN A FEW DEGREES OF NORMAL.
FOR FRIDAY AND SATURDAY, THE MAJORITY OF ENSEMBLE CLUSTERS KEEP THE
UPPER LEVEL PATTERN HIGH-ZONAL, WHICH WILL BRING A FEW DEGREES OF
WARMING TO THE AREA. HIGHS ARE FORECAST TO BE 5 TO 10 DEGREES
ABOVE AVERAGE.
BY SUNDAY MOST ENSEMBLE CLUSTERS INDICATE THE RETURN OF WEAK
TROUGHING WHICH HAS THE POTENTIAL TO COOL CONDITIONS A FEW DEGREES.
THERE STILL REMAINS SOME UNCERTAINTY IN THE TEMPERATURE FORECAST FOR
EARLY NEXT WEEK. THE CURRENT FORECAST FOLLOWS THE DETERMINISTIC NBM
WHICH CONTINUES TO BE MORE IN LINE WITH THE WARMER END OF MOST
OTHER ENSEMBLE GUIDANCE.
AVIATION
120400Z...COAST/VALLEYS...LOW CLOUDS BASED 700-1200 FT ARE PUSHING
INLAND, EVENTUALLY COVERING ALL OF THE ORANGE COUNTY LOWLANDS AND
REACHING TO THE INLAND VALLEYS OF SD CO. BY 08Z. VIS REDUCED TO 0-
3SM FOR INLAND VALLEYS WITH PATCHY FOG AND 3-6SM WITH BR FOR
ELEVATED COASTAL AREAS (200-600 FT MSL ELEVATION). THERE IS MODERATE
CONFIDENCE THAT BASES WILL RISE ABOVE 1000 FT MSL AT SOME POINT
EARLY TUESDAY MORNING, STARTING SOMETIME BETWEEN 09-14Z. AROUND A
70% CHANCE CIGS REACH INTO THE INLAND EMPIRE, 11-16Z, BRINGING
PATCHY IFR CIGS/VIS. BASES CONTINUE TO LIFT (AND VIS IMPROVES)
THROUGHOUT THE MORNING TO 1500-2500 FT MSL BUT ARE ONLY LIKELY TO
SCATTER OUT INLAND 18-21Z. WITHIN 10 MILES OF THE COAST, CIGS ARE
EXPECTED TO REMAIN PATCHY THROUGH THE AFTERNOON. CIGS BASED 1500-
2500 FT MSL DEVELOP QUICKLY AFTER 01Z WED, REACHING 20 MILES INLAND
BY AROUND 04Z WED. THERE IS GOOD CONFIDENCE FOR VIS REDUCTIONS BELOW
3SM AND FOG ALONG FOOTHILL SLOPES, OTHERWISE, LOWER CONFIDENCE FOR
VIS REDUCTIONS BELOW 3SM FOR EASTERN INLAND VALLEYS AND INLAND
EMPIRE VALLEYS.
OTHERWISE...SKC AND VFR THROUGH TUESDAY EVENING.
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...CO/PG
AVIATION/MARINE...WESTERINK
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page