253
FXUS66 KSGX 252052
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
152 PM PDT FRI APR 25 2025
SYNOPSIS
COOL AND CLOUDY WITH CHANCES OF RAIN AND MOUNTAIN SNOW THROUGH THE
WEEKEND. THERE IS ALSO A 10 TO 15 PERCENT CHANCE OF THUNDERSTORMS
FOR THE MOUNTAINS WESTWARD SATURDAY AFTERNOON. GUSTY SOUTHWEST TO
WEST WINDS FOR THE MOUNTAINS AND DESERTS THIS AFTERNOON INTO
SATURDAY EVENING ALONG AND BELOW THE DESERT SLOPES OF THE MOUNTAINS.
GRADUAL WARMING NEXT WEEK WITH HIGHS NEAR TO SLIGHTLY ABOVE
NORMAL.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
AT 1 PM, WINDS HAD INCREASED MAINLY THROUGH THE MOUNTAIN PASSES.
PEAK GUSTS SO FAR TODAY HAVE BEEN IN THE 50 TO 60 MPH RANGE. GUSTY
SOUTHWEST TO WEST WINDS WILL CONTINUE OVER THE MOUNTAINS AND DESERTS
THROUGH SATURDAY NIGHT. PEAK GUSTS OF 45 TO 55 MPH, LOCALLY UP TO 60
MPH WILL OCCUR ON THE FAVORED DESERT SLOPES AND BELOW THE PASSES.
WINDS WILL PEAK IN STRENGTH IN THE AFTERNOONS AND EVENINGS. GUSTY
WINDS MAY RESULT IN HAZARDOUS DRIVING CONDITIONS FOR HIGH PROFILE
VEHICLES AND AREAS OF BLOWING DUSTY MAY INHIBIT VISIBILITY. WINDS
WILL DIMINISH INTO SUNDAY MORNING.
AN UPPER LEVEL LOW PRESSURE SYSTEM WILL DIG SOUTH AND EAST ACROSS
SOUTHERN CALIFORNIA SATURDAY. THIS WILL BRING INCREASED CHANCES OF
PRECIPITATION, WITH THE HIGHEST CHANCES IN ORANGE COUNTY, INLAND
EMPIRE, AND THE SAN BERNARDINO COUNTY MOUNTAINS. THERE IS BETTER
CONSENSUS ON WHEN THE MAIN BAND OF PRECIPITATION WILL MOVE THROUGH
THE AREA ON SATURDAY. CURRENT RUNS OF OUR LOCAL WRF AND THE HRRR ARE
INDICATING THE BAND WILL ARRIVE IN THE AFTERNOON. AREAS OF DRIZZLE
OR LIGHT RAIN ARE POSSIBLE AHEAD OF THE MAIN ORGANIZED BAND OF
PRECIPITATION TONIGHT AND SATURDAY MORNING. RAINFALL RATES WILL BE
MOSTLY LIGHT TO MODERATE. HREF CHANCES OF HOURLY RAINFALL RATES
REACHING OR EXCEEDING 0.25 INCHES PER HOUR IS 15 TO 30 PERCENT, WITH
THE HIGHER CHANCES ON THE COASTAL MOUNTAIN SLOPES. THE COLD CORE OF
THE LOW IS EXPECTED TO MOVE OVERHEAD SATURDAY AFTERNOON/EVENING. THE
COLD AIR COMBINED WITH SOME WEAK INSTABILITY WILL LEAD TO A 10 TO 15
PERCENT CHANCE OF THUNDERSTORMS ALONG AND WEST OF THE MOUNTAINS.
RAINFALL AMOUNTS WILL GENERALLY BE LIGHT AND DECREASE FROM NORTH TO
SOUTH, ISOLATED HIGHER AMOUNTS ARE EXPECTED WHERE THUNDERSTORMS
OCCUR. SOME AREAS IN FAR SOUTHERN SAN DIEGO COUNTY MAY SEE LITTLE TO
NO PRECIPITATION. SNOW LEVELS WILL FLUCTUATE BETWEEN 5000 TO 6000 FT
WITH TOTALS OF 2 TO 6 INCHES ABOVE 5500 FT, HIGHEST IN THE SAN
GABRIEL MOUNTAINS NEAR MT SAN ANTONIO. SNOW ACCUMULATIONS ON THE
ROADWAYS MAY RESULT IN SLIPPERY DRIVING CONDITIONS, SO USE CAUTION
IF YOU ARE HEADING UP TO THE MOUNTAINS THIS WEEKEND!
WEAK TROUGHING LINGERS ACROSS THE REGION SUNDAY AND MONDAY
MAINTAINING COOL WEATHER WITH A DEEP MARINE LAYER. HIGHS REMAIN
AROUND 10 TO 20 DEGREES BELOW NORMAL INLAND ON SUNDAY, THEN AROUND 3
TO 5 DEGREES BELOW NORMAL ON MONDAY. ENSEMBLES ARE IN GOOD AGREEMENT
WITH AN UPPER RIDGE TRYING TO NUDGE IN FROM THE WEST ON TUESDAY FOR
MORE SIGNIFICANT WARMING AND HIGHS RETURNING TO A COUPLE DEGREES
ABOVE NORMAL, THEN ANOTHER WEAK WAVE DEVELOPING AND SWEEPING
SOUTHEASTERLY ACROSS THE WESTERN US AROUND WEDNESDAY AND THURSDAY
WHICH WILL MODERATE TEMPERATURES, THEN ANOTHER RIDGE TRYING TO BUILD
IN ON FRIDAY FOR MINOR WARMING. THE MARINE LAYER WILL BECOME MORE
SHALLOW TUESDAY AND WEDNESDAY WITH LOW CLOUDS CONFINED TO THE
COASTAL AREAS, THEN DEEPEN AGAIN ON THURSDAY - RIGHT IN TIME FOR MAY
GRAY TO BEGIN.
AVIATION
252015Z....COASTS/VALLEYS/COASTAL MOUNTAIN SLOPES...SATELLITE SHOWS
SCT-BKN CLOUDS WITH BASES 4000-6000FT MSL CONTINUE FOR ALL LOCATIONS
WEST OF THE MOUNTAINS. A MARINE LAYER WITH SIMILAR BASES/TOPS AS
OBSERVED THIS MORNING (3000-4000FT MSL) INCREASE AFTER 02Z SATURDAY
THOUGH MAY BE SOMEWHAT PATCHY IN THE EVENING, WITH A MORE UNIFORM
MARINE LAYER EXPECTED BY ABOUT 09Z SATURDAY. RAINFALL CHANCES
INCREASE BY 06Z, INCREASING THROUGH SATURDAY AFTERNOON AND EVENING.
RAINFALL AMOUNTS GENERALLY EXPECTED TO BE LIGHT. BASES WILL FALL TO
2000-2500FT MSL WITH ANY RAIN SHOWER, AND A THUNDERSTORM THREAT WILL
EXIST SATURDAY AFTERNOON AND EVENING. GUSTY AND ERRATIC WINDS ALONG
WITH HEAVY RAINFALL THAT MAY LEAD TO REDUCED VISIBILITY IN ANY STORM.
MOUNTAINS/DESERTS...WEST WINDS INCREASE THROUGH THIS AFTERNOON,
GUSTING 35-45 KTS, LOCALLY 50 KTS, OVER RIDGES, THROUGH PASSES AND
DESERT SLOPES INTO THIS EVENING. STRONG UP/DOWNDRAFTS ARE LIKELY,
WITH ISOLATED LLWS AND ROTORS IN LEE OF MOUNTAINS, SUCH AS VCNTY
KPSP. RAIN CHANCES DEVELOP AS EARLY AS 06Z SATURDAY, INCREASING INTO
THE AFTERNOON AND EVENING WHILE GUSTY WINDS DEVELOP FOR SIMILAR
LOCATIONS WITH SIMILAR SPEEDS AS FRIDAY. HEAVIEST RAIN POSSIBLE IN
THE MOUNTAINS, AND A THUNDERSTORM THREAT WILL EXIST IN THE AFTERNOON
AND EVENING. GUSTY AND ERRATIC WINDS ALONG WITH HEAVY RAINFALL THAT
MAY LEAD TO REDUCED VISIBILITY IN ANY STORM.
MARINE
SLIGHT CHANCE FOR THUNDERSTORMS OVER THE WATERS SATURDAY AFTERNOON
AND EVENING WHICH MAY BRING HEAVY RAINFALL AND REDUCED VISIBILITY,
AS WELL AS GUSTY AND ERRATIC WINDS AND LIGHTNING. OTHERWISE, NO
HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH TUESDAY.
BEACHES
ELEVATED SURF OF 3 TO 6 FEET WITH OCCASIONAL SETS TO 7 FEET SATURDAY
THROUGH TUESDAY, PEAKING SUNDAY NIGHT AND MONDAY. STRONG RIP
CURRENTS EXPECTED. SLIGHT CHANCE FOR THUNDERSTORMS AT THE BEACHES
SATURDAY AFTERNOON AND EVENING, WITH LIGHTNING AND GUSTY WINDS
POSSIBLE WITH ANY STORM.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...WINTER WEATHER ADVISORY FROM 9 AM TO 11 PM PDT SATURDAY FOR SAN
BERNARDINO COUNTY MOUNTAINS.
WIND ADVISORY UNTIL 11 PM PDT SATURDAY FOR APPLE AND LUCERNE
VALLEYS-SAN DIEGO COUNTY DESERTS-SAN GORGONIO PASS NEAR
BANNING.
PZ...NONE.
PUBLIC...CO
AVIATION/MARINE/BEACHES...ZUBER
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