451
FXUS66 KSGX 190009
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
509 PM PDT FRI SEP 18 2026
SYNOPSIS
TEMPERATURES REMAIN BELOW NORMAL INTO WEDNESDAY WITH A PRESENT
MARINE LAYER. WARMER WEATHER RETURNS FOR THE END OF NEXT WEEK AS
HIGH PRESSURE BUILDS.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
..UPDATED AVIATION DISCUSSION
MID-LEVEL WATER VAPOR SATELLITE IMAGERY SHOWS A TROUGH OVER THE
PACNW WITH A SQUISHED RIDGE JUST OFF THE OR COAST ON THE HEELS OF
THE TROUGH. TEMPERATURES WARM SATURDAY AS THE TROUGH IS PUSHED
EASTWARD AND THE RIDGE SETS UP OVER THE WEST COAST, INCREASING
HEIGHTS. EVEN WITH THIS PATTERN CHANGE, TEMPERATURES WILL STILL
REMAIN BELOW NORMAL BY ABOUT 1-4 DEGREES, WITH HIGHS IN THE MID 70S
FOR THE COAST & MOUNTAINS, 80S FOR INLAND SPOTS AND HIGH DESERT, AND
NEAR 100 FOR THE LOWER DESERTS. THE MARINE LAYER BOTH SATURDAY AND
SUNDAY MORNING WILL BE SLIGHTLY SHALLOWER THAN ITS BEEN THE PAST FEW
DAYS, BURNING OFF QUICKER AND NOT MAKING IT AS FAR INLAND.
THE RIDGE WON'T REMAIN IN PLACE FOR VERY LONG AS A SECONDARY TROUGH
IMMEDIATELY BEHIND IT PUNTS IT EASTWARD. THIS NEXT TROUGH IS POISED
TO BECOME A CLOSED LOW, SETTLING OVER CENTRAL CA BY MONDAY. ONSHORE
FLOW WILL INCREASE LATE SUNDAY AND MONDAY WHILE THE MARINE LAYER
WILL DEEPEN ONCE AGAIN. TEMPERATURES IN TURN WILL BE COOLER SUN-TUE,
COLDEST MONDAY, WITH HIGHS 5-12 DEGREES BELOW NORMAL.
THE PATTERN CHANGES ONCE AGAIN WEDNESDAY AS THE TROUGH BECOMES
ABSORBED INTO THE UPPER LEVEL PATTERN WITH A MASSIVE LOW SITTING OFF
THE CANADIAN COASTLINE. HIGH PRESSURE SLIDES OVER THE SOCAL WATERS
AND BUILDS QUICKLY LATE NEXT WEEK. THIS SHOULD RETURN US TO A
WARMING TREND, REBOUNDING TEMPERATURES BACK ABOVE NORMAL. AT THIS
POINT, MODELS DISAGREE ON THE OVERALL PLACEMENT OF THE HIGH, AS WELL
AS HOW THE AFOREMENTIONED CANADIAN LOW MIGHT MOVE. AS SUCH, MODELS
SHOW A SIGNIFICANT TEMPERATURE SPREAD FOR THE END OF NEXT WEEK AND
INTO THE WEEKEND, WITH SOME RESOLVING HIGHS CLOSER TO NEAR NORMAL
WITH OTHERS AROUND 5-8 DEGREES ABOVE. SOME GUIDANCE ALSO INDICATES
THAT THE SOUTHWESTERLY FLOW COULD PUSH MONSOONAL MOISTURE BACK UP
INTO THE SOCAL MOUNTAINS, BUT A CLEARER PICTURE OF WHERE THE HIGH
PRESSURE MAY BE IS NEEDED BEFORE THERE IS SIGNIFICANT CONFIDENCE IN
THIS.
AVIATION
190000Z...COAST/VALLEYS...LOW CLOUDS EXPECTED TO DEVELOP STARTING IN
SAN DIEGO COUNTY 04-08Z SAT AT 2000-3000 FT MSL. CLOUDS WILL SPREAD
NORTH INTO ORANGE COUNTY AND EAST IN PORTIONS OF THE VALLEYS EARLY
SAT MORNING. CLOUDS ARE UNLIKELY TO MAKE THEIR WAY INTO VCNTY
KONT/KSBD (ONLY ABOUT A 15% CHANCE FOR CIGS). CLOUDS CLEAR OFFSHORE
AGAIN 16-18Z SAT.
MOUNTAINS/DESERTS...MOSTLY CLEAR AND VFR CONDITIONS THROUGH SAT.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH WEDNESDAY.
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...ZUBER
AVIATION/MARINE...CO
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