460
FXUS66 KSGX 250432
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
932 PM PDT THU APR 24 2025
SYNOPSIS
A COOLING TREND CONTINUES THROUGH THE WEEKEND AS HIGHS FALL TO 10
TO 20 DEGREES BELOW NORMAL. THE MARINE LAYER WILL DEEPEN ONTO THE
COASTAL MOUNTAIN SLOPES WITH PATCHY DRIZZLE AND A SLIGHT CHANCE
OF LIGHT SHOWERS FOR EARLY FRIDAY AND A CHANCE OF SHOWERS FOR LATE
FRIDAY NIGHT THROUGH LATE SATURDAY NIGHT. THE MOST LIKELY TIME
FOR SHOWERS IS FOR SATURDAY AFTERNOON ALONG WITH A SLIGHT CHANCE
OF THUNDERSTORMS FOR ORANGE AND PORTIONS OF SOUTHWESTERN SAN
BERNARDINO COUNTIES. THERE WILL BE PERIODS OF STRONGER AND GUSTY
SOUTHWEST TO WEST WINDS FOR THE MOUNTAINS AND DESERTS FOR FRIDAY
AFTERNOON INTO SATURDAY EVENING WITH GUSTS TO 45 TO 55 MPH ALONG
AND BELOW THE DESERT SLOPES OF THE MOUNTAINS. QUIETER WEATHER BY
SUNDAY WITH A DRYING AND WARMING TREND FOR NEXT WEEK WITH NEAR OR
ABOVE NORMAL HIGH TEMPERATURES FOR INLAND AREAS BEGINNING
TUESDAY.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
UPDATE: THE LATEST HIGH RES MODELS ARE INDICATING THAT THERE WILL BE
ENOUGH INSTABILITY FOR THERE TO BE A FEW THUNDERSTORMS POSSIBLE
DURING THE AFTERNOON HOURS ON SATURDAY, MAINLY FOR THE SAN
BERNARDINO MOUNTAINS AND INLAND EMPIRE. RAINFALL RATES WILL
GENERALLY BE IN THE 0.10 TO 0.20 RANGE FOR THE COASTAL AND INLAND
AREAS, AND HIGHER TO AROUND 0.30 FOR THE WESTERN FACING SLOPES, FOR
LOCATIONS IN ORANGE COUNTY AND NORTHWARD, AND LESSER AMOUNTS FOR SAN
DIEGO COUNTY. LOCALLY HIGHER AMOUNTS WILL BE POSSIBLE WITH ANY
HEAVIER SHOWERS/THUNDERSTORMS THAT DEVELOP. THERE WILL STILL BE THE
POSSIBILITY OF SOME DRIZZLE DEVELOPING BY LATER TONIGHT THROUGH
TOMORROW MORNING AS WELL, AS THE LOWER LEVELS CONTINUE TO BECOME
MORE SATURATED. OTHER THAN THAT, THE FORECAST IS STILL APPEARING
TO BE ON TRACK, WITH DRIER CONDITIONS AND A GRADUAL WARMUP
BEGINNING SUNDAY THROUGH THE MIDDLE OF NEXT WEEK.
(DISCUSSION SUBMITTED AT 137 PM):
THE MARINE LAYER CLEARED OUT OF SAN DIEGO AND RIVERSIDE COUNTIES
THIS MORNING, AND IS NOW QUICKLY BURNING OFF IN ORANGE COUNTY.
CLOUDS WILL CONTINUE TO CLEAR TOWARDS THE COAST THROUGH THE
AFTERNOON BEFORE ANOTHER, DEEPER, MARINE LAYER BUILDS BACK IN
TONIGHT. HEIGHTS CONTINUE TO FALL THROUGH SATURDAY AS A TROUGH OFF
THE COAST OF CANADA BECOMES A CUTOFF LOW AND SWEEPS DOWN INTO
CALIFORNIA. AHEAD OF THIS LOW, GUSTY WEST WINDS DEVELOP ACROSS THE
MOUNTAINS AND DESERTS AS THE GRADIENT TIGHTENS ON FRIDAY, EXTENDING
INTO THE EVENING. A WIND ADVISORY HAS BEEN ISSUED FOR FRIDAY
AFTERNOON THROUGH LATE SATURDAY NIGHT, WITH GUSTS UP TO 45 MPH IN
THE DESERTS AND UP TO 55 MPH IN THE MOUNTAIN PASSES. AREAS OF
BLOWING DUST WILL BE POSSIBLE BOTH DAYS, PRIMARILY IN THE DESERTS,
WITH REDUCED VISIBILITY DOWN TO 3 MILES OR LESS IN SOME SPOTS.
FURTHER EAST, THE DEEPER MARINE LAYER SHOULD BE SUFFICIENT FOR SOME
MORNING DRIZZLE, HEAVY AT TIMES, ESPECIALLY IN THE VALLEYS AND UP
AGAINST THE COASTAL SLOPES FRIDAY MORNING. MOISTURE LINGERS AS
THE LOW PUSHES INTO CENTRAL CALIFORNIA SATURDAY MORNING, WITH SOME
LIGHT RAIN/SNOW SHOWERS DEVELOPING ACROSS THE FURTHEST NORTH
REGIONS. SNOW LEVELS FALL TO AROUND 4800FT BY SATURDAY AFTERNOON,
AND WHILE THE LOW LOOKS TO PUSH SOUTH ENOUGH FOR SOME
PRECIPITATION, ANY ACCUMULATIONS WILL BE EXTREMELY LIGHT. MODELS
CONTINUE TO SHOW SOME LIMITED INSTABILITY AND ISOLATED
THUNDERSTORMS MAY DEVELOP LATE SATURDAY MORNING THROUGH EARLY
EVENING, PRIMARILY ACROSS THE AREA STRETCHING FROM THE SAN
BERNARDINO MOUNTAINS DOWN INTO THE IE AND INTO ORANGE COUNTY. ANY
THUNDERSTORMS THAT MANAGE TO DEVELOP WILL BRING GUSTY WINDS, AND
BRIEF, HEAVY RAIN WHICH COULD LEAD TO SOME LOCALIZED HIGHER QPF
AMOUNTS. OUTSIDE OF ANY THUNDERSTORMS, QPF AMOUNTS WILL GENERALLY
REMAIN BELOW 0.10" THROUGH ALL OF SATURDAY.
AS THE LOW MOVES UP INTO NEVADA SUNDAY AFTERNOON, ANY LINGERING
PRECIPITATION AND GUSTY WINDS WILL QUICKLY END. WEAK RIDGING BEGINS
TO BUILD BACK IN OVER SOUTHERN CALIFORNIA, WITH TEMPERATURES WARMING
INTO EARLY NEXT WEEK. HIGHS RETURN TO AT OR ABOVE NORMAL BY TUESDAY,
HOLDING STEADY THROUGH LATE WEEK AS ZONAL FLOW ALOFT DEVELOPS. AT
THIS POINT, MODELS LOOK FAIRLY DRY THROUGH AT LEAST MID WEEK.
AVIATION
250330Z....COASTS/VALLEYS/COASTAL MOUNTAIN SLOPES...CLOUDS BASED AT
2500-3500 FEET MSL WITH TOPS CLIMBING TO 5500 FEET WILL GRADUALLY
FILL THE ENTIRE COASTAL BASIN. VIS REDUCED 0-5SM IN FOOTHILLS.
PATCHY -DZ BETWEEN 10-18Z FRIDAY WITH ACCOMPANYING LOWER CIGS TO
2000 FEET MSL AND LOWER VIS 3-5SM. CLOUDS START TO DISPERSE 17-19Z
FRIDAY WITH SOME BKN CLOUDS PERSISTING FAR INLAND AND IN FOOTHILLS.
CLOUDS INCREASING AGAIN AFTER 02Z FRIDAY EVENING.
MOUNTAINS/DESERTS...VARIABLE HIGH CLOUDS THROUGH FRIDAY. WEST WINDS
INCREASE AFTER 22Z FRIDAY, GUSTING 35-45 KTS, LOCALLY 50 KTS, OVER
RIDGES, THROUGH PASSES AND DESERT SLOPES. STRONG UP/DOWNDRAFTS ARE
LIKELY, WITH ISOLATED LLWS AND ROTORS IN LEE OF MOUNTAINS, SUCH AS
VCNTY KPSP.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH TUESDAY.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...WIND ADVISORY FROM 2 PM FRIDAY TO 11 PM PDT SATURDAY FOR APPLE
AND LUCERNE VALLEYS-SAN DIEGO COUNTY DESERTS-SAN GORGONIO
PASS NEAR BANNING.
PZ...NONE.
UPDATE...STEWEY
PUBLIC...ZUBER
AVIATION/MARINE...MARTIN
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