493
FXUS66 KSGX 100413
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
913 PM PDT THU APR 9 2026
SYNOPSIS
TWO LOW PRESSURE SYSTEMS WILL IMPACT THE REGION INTO EARLY NEXT
WEEK, BRINGING STRONGER WINDS FOR INLAND AREAS. THIS WILL ALSO
BRING COOLER WEATHER WITH THE CHANCE OF LIGHT TO MODERATE
RAINFALL. THE HEAVIEST RAINFALL AND MOUNTAIN SNOWFALL IS EXPECTED
ON SUNDAY, WHERE THERE IS A SLIGHT CHANCE OF THUNDERSTORMS WEST OF
THE MOUNTAINS. THE WEATHER SYSTEM MAY LINGER OVER THE AREA INTO
MONDAY, BRINGING ADDITIONAL LIGHT SHOWERS. DRIER AND SLIGHTLY
WARMER WEATHER IS EXPECTED BY THE MIDDLE AND END OF NEXT WEEK.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
..UPDATED AVIATION/MARINE DISCUSSION
A LOW PRESSURE SYSTEM TO THE NORTHWEST HAS BROUGHT WIDESPREAD
CLOUDS, LOWER TEMPERATURES AND STRONGER ONSHORE FLOW. MOST OF THE
CLOUDS ARE HIGH CLOUDS AND THERE IS A WEAK MARINE LAYER INVERSION.
TEMPERATURES THIS AFTERNOON WERE GENERALLY LOWER THAN
YESTERDAY...AS MUCH AS 10 DEGREES LOWER IN THE MOUNTAINS AND HIGH
DESERTS. THE STRENGTHENING ONSHORE FLOW IS PRODUCING SOUTHWEST TO
WEST WINDS GUSTING 25-35 MPH IN THE MTN PASSES AND ADJACENT DESERT
SLOPES.
THE LOW WILL MOVE CLOSER TO THE REGION FRIDAY, USHERING IN COOLER
WEATHER. HIGHS WEST OF THE MOUNTAINS INTO THE HIGH DESERT WILL
EITHER BE IN THE 60S OR 70S, WITH PALM SPRINGS SEEING ONLY A 25%
CHANCE OF HITTING 90 DEGREES. WEST WINDS WILL BE PRETTY SIMILAR TO
THURSDAY'S WINDS ACROSS MOUNTAINS AND DESERTS.
THE LOW PRESSURE SYSTEM NEAR THE BAY AREA AND ANOTHER CURRENTLY IN
THE GULF OF ALASKA WILL MOVE INTO THE REGION OVER THE NEXT FEW
DAYS. THE FIRST SYSTEM WILL LIKELY BE WEAKER AND STAY FURTHER TO
THE NORTH. THE LOW PRESSURE SYSTEM NEAR THE BAY AREA WILL MOVE
NEAR OUR REGION BY FRIDAY NIGHT INTO SATURDAY. MODELS CONTINUE TO
SHOW A DOWNWARD TREND IN PRECIPITATION ESTIMATES DURING THIS TIME,
WITH MOSTLY DRY CONDITIONS WITH ISOLATED LIGHT SHOWERS ALONG AND
WEST OF THE MOUNTAINS EARLY FRIDAY EVENING INTO SATURDAY MORNING.
ACCUMULATIONS WILL MOSTLY BE A FEW HUNDREDTHS FOR THE COAST /
VALLEYS TO NEAR ONE QUARTER INCH ACROSS THE MOUNTAIN COASTAL
SLOPES.
THE AREA OF LOW PRESSURE SITUATED IN THE GULF OF ALASKA WILL
LIKELY BE MORE POTENT. THIS WILL BRING A GREATER CHANCE FOR MORE
WIDESPREAD SHOWERS ACROSS THE REGION. PREFRONTAL SHOWERS WILL
BEGIN AS EARLY AS SATURDAY EVENING WEST OF THE MOUNTAINS WITH
SHOWERS BECOMING MORE WIDESPREAD OVERNIGHT INTO SUNDAY MORNING OR
AFTERNOON. THIS SYSTEM WILL BE COLDER, SO THE CHANCE FOR
THUNDERSTORMS HAS INCREASED FOR AREAS WEST OF THE MOUNTAINS ON
SUNDAY. MOST AREAS WEST OF THE MOUNTAINS ON SUNDAY WILL SEE NEAR
0.25-0.50" OF RAINFALL (NBM CHANCE FOR GREATER THAN ONE HALF INCH
OVER THIS AREA IS 20-40%). SNOW LEVELS WILL START TO FALL BELOW
7,000 FEET BY SATURDAY NIGHT, GOING DOWN NEAR 5,500 FEET BY SUNDAY
NIGHT. AREAS LIKE WRIGHTWOOD AND BIG BEAR LAKE HAVE NEAR A 25-40%
CHANCE TO SEE SNOWFALL OVER 1 INCH. MODEL GUIDANCE CONTINUES TO
BE IN FAIR AGREEMENT ON THE POTENT AREA OF LOW PRESSURE BECOMING A
MORE OPEN WAVE TROUGH, WHERE ANOTHER WEAK SHORTWAVE MAY MOVE OVER
THE AREA INTO MONDAY. IF THIS OCCURS, ADDITIONAL LIGHT
PRECIPITATION WOULD OCCUR, INCLUDING LIGHT MOUNTAIN SNOW. SUNDAY
AND MONDAY WILL BE THE COOLEST DAYS OF THE NEXT WEEK. HIGH
TEMPERATURES WILL BE AROUND 5 TO 15 DEGREES BELOW NORMAL. MOUNTAIN
COMMUNITIES WILL HAVE HIGHS IN THE 40S AND LOWS IN THE 20S AND
30S WITH MAINLY HIGHS IN THE 60S WEST OF THE MOUNTAINS INTO THE
HIGH DESERT. COMFORTABLE TEMPERATURES FOR THE COACHELLA VALLEY
WILL OCCUR THIS WEEKEND WITH HIGHS IN THE 80S ON SATURDAY TO 70S
ON SUNDAY.
TUESDAY INTO THE LATTER PART OF NEXT WEEK LOOKS DRY AS WEAK
TROUGHING OCCURS. THIS WILL KEEP TEMPERATURES IN CHECK WITH HIGHS
CLOSER TO NORMAL WITH LIGHTER WINDS.
AVIATION
100330Z...COASTS/VALLEYS...LOW CLOUDS WILL BECOME MORE WIDESPREAD
ALONG THE COAST THROUGH 08Z WITH BASES 1000-2000 FT MSL. LOW CLOUDS
ARE EXPECTED TO REACH INTO THE INLAND EMPIRE 09-12Z, WITH A 40-60%
CHANCE OF BASES UNDER 1000 FT. CLOUDS SCATTER TOWARD THE COAST AGAIN
15-18Z. BKN-OVC LOW TO MID-LEVEL CLOUDS EXPECTED FRI EVENING, WITH
VCSH FOR ORANGE COUNTY STARTING AROUND 03Z SAT.
MOUNTAINS/DESERTS
WEST TO SOUTHWEST WINDS WITH GUSTS 35-45 KT
THROUGH PASSES, ALONG DESERTS SLOPES AND LOCALLY INTO THE DESERTS
OVERNIGHT. AREAS BLDU (VIS 3-5SM) EXPECTED. MODERATE UP/DOWNDRAFTS
IN LEE OF MTNS. WINDS BRIEFLY WEAKEN LATE FRI MORNING BEFORE
STRENGTHENING TO SIMILAR SPEEDS AFTER 20Z FRI.
MARINE
THERE IS A SLIGHT CHANCE OF THUNDERSTORMS SUNDAY AFTERNOON.
ADDITIONALLY THERE WILL BE PERIODS OF INCREASED NORTHWEST WINDS WITH
GUSTS 15 TO 20 KT AND CHOPPY SEAS THAT COULD GENERATE HAZARDOUS
CONDITIONS THROUGH THE DAY SUNDAY.
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...APR/PG
AVIATION/MARINE...CO
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