632
FXUS66 KSGX 222039
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
139 PM PDT WED OCT 22 2025
SYNOPSIS
COOLER WEATHER TODAY DESPITE A PATCHY MARINE LAYER THIS MORNING,
WITH GUSTY WINDS ON THE EASTERN SLOPES OF THE MOUNTAINS THIS
AFTERNOON AND EVENING. A DEEPER MARINE LAYER TONGIHT WILL BACK UP
TO THE COASTAL SLOPES OF THE MOUNTAINS WITH AREAS OF LOW
VISIBILITY FOR THURSDAY MORNING. A WARMING AND DRYING TREND
THURSDAY AND FRIDAY WITH HIGHS RETURNING TO NEAR NORMAL BEFORE
COOLER AND WINDIER WEATHER RETURNS FOR THE WEEKEND. WARMER
TEMPERATURES NORMAL TO ABOVE NORMAL FOR MONDAY-WEDNESDAY.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
WATER VAPOR SATELLITE IMAGERY SHOWS A LARGE UPPER LEVEL LOW
POSITIONED ALONG THE CA/NV BORDER, USHERING IN SHOWERS AND STORMS
FOR MUCH OF THE SIERRA NEVADA. THIS SYSTEM FAILED TO MAKE IT FAR
ENOUGH SOUTH FOR AMPLE MOISTURE TO REACH SOUTHERN CALIFORNIA,
ALTHOUGH A FEW LIGHT SHOWERS/STORMS WERE OBSERVED IN THE MOUNTAINS
AND COACHELLA VALLEY EARLY THIS MORNING. AS THE LOW MOVES EASTWARD
TODAY, BOTH THE MOUNTAIN PASSES AND LOWER DESERTS WILL GUST UP TO 50-
55 MPH OUT OF THE WEST, WITH THESE WINDS LINGERING THROUGH TONIGHT.
AS THE LOW EXITS, A DEEPER MARINE LAYER DEVELOPS TONIGHT AND PUSHES
UP AGAINST THE COASTAL SLOPES OF THE MOUNTAINS INTO THURSDAY
MORNING. PREVIOUS HI-RES MODEL RUNS WERE DEVELOPING MARINE LAYER
DRIZZLE FOR THURSDAY MORNING ACROSS THE VALLEYS AND INLAND AREAS,
BUT THE DEEPNESS LOOKS TO BE INSUFFICIENT FOR DRIZZLE TO DEVELOP.
STILL, A MORE WIDESPREAD MARINE LAYER FOR INLAND AREAS THURSDAY
MORNING WILL LIMIT WARMING A BIT AND HIGHS TOMORROW SHOULD BE 3-5
DEGREES BELOW NORMAL.
WITH THE DEPARTURE OF THE AFOREMENTIONED LOW AND THE TRACK OF A
LARGER LOW OVER THE PACNW, THE END OF THE WEEK WILL FEATURE RIDING
OVER SOCAL AND A QUICK WARM UP FOR FRIDAY. HIGHS WILL WARM 5-9
DEGREES ABOVE THURSDAY, WITH TEMPERATURES IN THE 70S FOR THE COAST,
80S FOR VALLEYS AND INLAND EMPIRE, MID 90S FOR THE DESERTS AND
COACHELLA VALLEY, 60S TO 70S IN THE MOUNTAINS, AND 80S IN THE HIGH
DESERT. BY SATURDAY, THE LARGER LOW OVER THE PACNW WILL SHIFT A
BIT SOUTHWARD, SHUNTING THE RIDGE AND THERMAL AXIS EASTWARD AND
MORE ZONAL FLOW ALOFT SETTLES IN. THE MARINE LAYER WILL DEEPEN
ONCE MORE, AND TEMPERATURES WILL COOL A FEW DEGREES - NEAR NORMAL
FOR SATURDAY AND 2-5 DEGREES BELOW NORMAL FOR SUNDAY. THE GRADIENT
TIGHTENS SIGNIFICANTLY ON SUNDAY, AND ANOTHER WINDY DAY WILL
ENSUE. STRONG WEST WINDS WILL DEVELOP BY PEAK HEATING ON SUNDAY,
PREVAILING INTO VERY EARLY MONDAY AS THE LOW PROGRESSES EAST.
DESERTS, MOUNTAINS, AND PASSES MAY ALL SEE GUSTS EXCEEDING 30 MPH
AT TIMES, ESPECIALLY FOR THE NORTHERN FORECAST AREAS. AT THIS
POINT, THIS NEXT SYSTEM LOOKS TO BE DRY AND ANY ASSOCIATED
SHOWERS/STORMS WILL REMAIN TOO FAR NORTH FOR US TO BENEFIT FROM.
FOR EARLY NEXT WEEK, MORE ZONAL FLOW TO WEAK RIDING WILL SETTLE IN
FOR THE WESTERN STATES. THE NEXT SYSTEM OCCURRING BY MID WEEK
WILL BE AN OPEN TROUGH OFF THE COAST OF WASHINGTON TRANSITIONING
TO A CLOSED LOW WHILE A SEPARATE LOW OVER THE GREAT LAKES WORKS
IN CONJUNCTION TO SQUEEZE THE RIDGE, INCREASING HEIGHTS
SIGNIFICANTLY OVER CALIFORNIA. WHILE SLOW WARMING WILL BE OBSERVED
MONDAY OVER SUNDAY, MORE SUBSTANTIAL WARMING WILL OCCUR FOR
TUESDAY AND WEDNESDAY AS HIGHS RETURN 4-10 DEGREES ABOVE NORMAL.
AVIATION...222000Z...COAST/VALLEYS
MOSTLY CLEAR SKIES THROUGH
LATE THIS AFTERNOON ASIDE FROM ISOLATED PATCHES OF CU IN THE VALLEYS.
PATCHY LOW CLOUDS 2000-3000 FT MSL WILL FORM IN SAN DIEGO CO AFTER
00Z, GRADUALLY COVERING MOST OF THE COASTAL BASIN INTO FOOTHILLS BY
EARLY THURSDAY. THESE WILL SCATTER OUT FROM MOST INLAND AREAS 13-16Z
BUT LINGER ALONG THE COAST THROUGH ABOUT THU 18Z.
MOUNTAINS/DESERTS...WESTERLY WINDS WITH STRONGEST GUSTS 35-45 KTS
THROUGH MOUNTAIN PASSES AND ON DESERT SLOPES THROUGH LATE THIS
EVENING. STRONG UP/DOWNDRAFTS AND LOCAL LLWS IN LEE OF MOUNTAINS,
SUCH AS VCNTY KPSP.
MARINE
NORTHWEST WIND GUSTS AROUND 20 KNOTS IN THE IMMEDIATE VICINITY OF
SAN CLEMENTE ISLAND TODAY, AND LIKELY AGAIN SUNDAY. OTHERWISE, NO
HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH MONDAY.
SGX WATCHES/WARNINGS/ADVISORIES
CA...WIND ADVISORY UNTIL MIDNIGHT PDT TONIGHT FOR SAN DIEGO COUNTY
DESERTS-SAN GORGONIO PASS NEAR BANNING.
PZ...NONE.
PUBLIC...ZUBER
AVIATION/MARINE...CSP
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