474
FXUS66 KSGX 260935
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
235 AM PDT SAT APR 26 2025
SYNOPSIS
COOL AND CLOUDY WEATHER IS EXPECTED THROUGH TODAY, WITH LIGHT
SHOWERS AND MOUNTAIN SNOW. THERE WILL ALSO BE STRONG SOUTHWEST TO
WEST WINDS, STRONGEST THROUGH MOUNTAIN PASSES INTO DESERTS. THERE
IS A SLIGHT CHANCE OF THUNDERSTORMS THIS AFTERNOON. HIGH PRESSURE
WILL SLOWLY REBUILD NEXT WEEK FOR FAIR AND WARMER WEATHER, WITH
THE USUAL COASTAL CLOUDS DURING THE NIGHTS AND MORNINGS.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
THIS MORNING...THE MARINE LAYER IS NOW AROUND 7,000 FT DEEP AND
LOW CLOUDS ARE NOW COVERING MOST OF THE REGION FROM THE COAST TO
THE MOUNTAINS. A FEW LOCATIONS IN THE FOOTHILLS AND COASTAL MTN
SLOPES HAVE REPORTED A COUPLE OF HUNDREDTHS OF AN INCH OF RAIN IN
THE LAST FEW HOURS. GUSTY SOUTHWEST TO WEST WINDS HAVE DEVELOPED
IN THE MTNS AND DESERTS, WITH THE WIND-PRONE LOCATIONS REPORTING
GUSTS OF 30-60 MPH IN THE LAST HOUR.
A LOW PRESSURE SYSTEM CURRENTLY ABOUT 200 MILES OFF THE COAST OF
MONTEREY WITH A COLD FRONT EXTENDING TO THE SOUTH AND WEST OF THE
PARENT LOW. MOSTLY LIGHT RAIN SHOWERS ACCOMPANY THE FRONTAL
BOUNDARY. THIS SYSTEM WILL MOVE ONSHORE TODAY, WITH THE FRONT AND
ASSOCIATED SHOWERS REACHING ORANGE COUNTY, WESTERN RIVERSIDE AND
WESTERN SAN BERNARDINO COUNTIES AROUND 11 AM...THIS IS ACCORDING
TO THE CURRENT GUIDANCE FROM THE SHORT-RANGE HIGH-RESOLUTION
MODELS. THE BAND OF ORGANIZED FRONTAL SHOWERS WILL MOVE OFF TO THE
EAST LATE THIS AFTERNOON, WITH SHOWERS ENDING FROM NORTHWEST TO
SOUTHEAST AND LINGERING IN SAN DIEGO COUNTY LATE IN THE AFTERNOON.
CURRENT RAINFALL ESTIMATES BELOW THE SNOW LINE ARE FOR A FEW
HUNDREDTHS TO A QUARTER OF AN INCH IN THE LOW ELEVATIONS WEST OF
THE MOUNTAINS, A QUARTER TO NEARLY THREE- QUARTERS OF AN INCH IN
THE MOUNTAINS AND THE COASTAL SLOPES. THE LOWER DESERTS ARE
UNLIKELY TO RECEIVE MEASURABLE RAINFALL AND THE UPPER DESERTS WILL
LIKELY ONLY GET A FEW HUNDREDTHS OF AN INCH. THE SNOW LEVEL WILL
BE AROUND 5,000 FEET WITH SNOW ACCUMULATIONS UNLIKELY BELOW 5,500
FEET. ABOVE 6,000 FEET, THERE IS A 70-100 PERCENT CHANCE FOR 3+
INCHES OF SNOW IN THE SAN BERNARDINO AND EASTERN SAN GABRIEL
MOUNTAINS, AND A 40-70 PERCENT CHANCE IN THE SAN JACINTO
MOUNTAINS. THERE IS ALSO A 20-50 PERCENT CHANCE OF A DUSTING AT
THE PEAKS OF THE MOUNTAINS IN SAN DIEGO COUNTY. HIGH TEMPERATURES
TODAY WILL BE A FEW DEGREES BELOW SEASONAL AVERAGES IN THE COASTAL
AREAS AND WESTERN VALLEYS BUT UP TO 20 DEGREES BELOW NORMAL IN THE
INLAND VALLEYS, THE MOUNTAINS AND IN THE DESERTS. COLD AIR ALOFT
AND INSTABILITY WILL BRING A SLIGHT CHANCE FOR THUNDERSTORMS THIS
AFTERNOON, MAINLY IN ORANGE, WESTERN RIVERSIDE AND WESTERN SAN
BERNARDINO COUNTIES. THE HIGH-RESOLUTION ENSEMBLE MODEL GIVES IT
ABOUT A 10 PERCENT CHANCE FOR LIGHTNING. STRONG AND GUSTY WESTERLY
WINDS WILL CONTINUE INTO TONIGHT BEFORE WEAKENING BY SUNDAY
MORNING.
EVEN AFTER THIS LOW PRESSURE SYSTEM MOVES EAST INTO THE SOUTHERN
GREAT BASIN, PERSISTENT TROUGHING WILL KEEP TEMPERATURES BELOW
NORMAL THROUGH MONDAY EVEN AS THEY GRADUALLY RISE EACH DAY.
TEMPERATURES WILL RETURN TO NEAR NORMAL ON TUESDAY AND SLOWLY RISE
THROUGH FRIDAY, REACHING THE MID TO UPPER 70S IN THE INLAND
VALLEYS. BEYOND WEDNESDAY, SOLUTIONS AMONG ENSEMBLE MEMBERS ACROSS
MODEL PLATFORMS BEGIN TO DIVERGE SIGNIFICANTLY ERODING CONFIDENCE
IN FORECAST DETAILS. IN GENERAL, WE CAN EXPECT SEASONAL WEATHER,
WITH MINOR DAY-TO-DAY VARIATIONS IN THE MARINE LAYER CLOUDS AND
FOG DURING THE NIGHTS AND MORNINGS. THE MOUNTAINS AND DESERTS WILL
HAVE FAIR WEATHER AND NEAR TO SLIGHTLY ABOVE NORMAL TEMPERATURES.
AVIATION
260830Z....COASTS/VALLEYS/COASTAL MOUNTAIN SLOPES...SCT-BKN CLOUDS
WITH BASES 3000-6000 FT MSL WILL GRADUALLY INCREASE THIS MORNING AND
THROUGH THE EVENING. MOUNTAIN TERRAIN WILL BE OBSCURED AT TIMES IN
CLOUDS. ISOLATED SHRA WILL OCCUR THIS MORNING, THEN BECOME SCT OR
EVEN NUMEROUS THIS AFTERNOON, WITH LOCAL VIS 3-5 MILES AND BASES
LOCALLY AS LOW AS 2000 FT MSL. THERE IS A SLIGHT CHANCE OF TS THIS
AFTERNOON WITH ANY LIGHTNING STRIKES BEING ISOLATED. SHRA WILL BE
ISOLATED/SCT THIS EVENING, THEN CHANCES OF SHRA WILL DIMINISH WITH
GRADUAL CLEARING OCCURRING OVERNIGHT SATURDAY INTO SUNDAY MORNING.
MOUNTAINS/DESERTS...AREAS OF WESTERLY WINDS WITH GUSTS 30-50 KT WILL
CONTINUE THROUGH THIS EVENING, STRONGEST FROM THE MOUNTAIN CRESTS
THROUGH THE DESERT MOUNTAIN SLOPES. PSP COULD PERIODIC GUSTS 30-35
KT AT TIMES, ESPECIALLY THIS AFTERNOON/EVENING. ISOLATED SHRA/SHSN
WILL OCCUR IN THE MOUNTAINS THIS MORNING, BECOMING SCT/LOCALLY
NUMEROUS DURING THE AFTERNOON/EVENING, WITH WIDESPREAD TERRAIN
OBSCURATIONS IN CLOUDS. SHRA CHANCES WILL DIMINISH WITH GRADUAL
CLEARING OVERNIGHT SATURDAY INTO SUNDAY MORNING.
MARINE
THERE IS A SLIGHT CHANCE OF THUNDERSTORMS OVER THE WATERS THIS
AFTERNOON AND EVENING WHICH MAY BRING BRIEF HEAVY RAINFALL, REDUCED
VISIBILITY, BRIEF GUSTY AND ERRATIC WINDS AND LIGHTNING. OTHERWISE,
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH WEDNESDAY.
BEACHES
ELEVATED SURF OF 3 TO 6 FEET WITH SETS TO 7 FEET WILL OCCUR TODAY
THROUGH TUESDAY, PEAKING SUNDAY NIGHT AND MONDAY, AND HIGHEST ON
SOUTH FACING BEACHES. STRONG RIP CURRENTS WILL OCCUR. THERE IS A
SLIGHT CHANCE OF THUNDERSTORMS AT THE BEACHES THIS AFTERNOON AND
THROUGH THE EARLY EVENING HOURS, 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 THIS MORNING TO 11 PM PDT THIS
EVENING FOR RIVERSIDE COUNTY MOUNTAINS-SAN BERNARDINO
COUNTY MOUNTAINS.
WIND ADVISORY UNTIL 11 PM PDT THIS EVENING FOR APPLE AND LUCERNE
VALLEYS-SAN DIEGO COUNTY DESERTS-SAN GORGONIO PASS NEAR
BANNING.
PZ...NONE.
PUBLIC...PG
AVIATION/MARINE/BEACHES...STEWEY
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