415
FXUS66 KSGX 202340
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
440 PM PDT MON APR 20 2026
SYNOPSIS
COOLER CONDITIONS THROUGH THE MIDDLE OF THE WEEK WITH PERIODS OF
ELEVATED WINDS OVER THE MOUNTAINS AND INTO THE DESERTS. LIGHT
PRECIPITATION IS POSSIBLE WEST OF THE MOUNTAINS TUESDAY EVENING
INTO WEDNESDAY, WHICH COINCIDES WITH THE TIMING OF THE STRONGEST
WESTERLY WINDS. THURSDAY WILL WARM A FEW DEGREES. COOLER
CONDITIONS LIKELY THIS WEEKEND, WITH PERIODS OF INCREASED WINDS
AND POTENTIALLY ANOTHER ROUND OF LIGHT PRECIPITATION WEST OF THE
MOUNTAINS.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
UPDATED AVIATION/MARINE DISCUSSION
HIGH TEMPERATURES TODAY WEST OF THE MOUNTAINS ARE EXPECTED TO BE A
FEW DEGREES COOLER THAN YESTERDAY WITH NO CHANGE OR A FEW DEGREES OF
WARMING IN THE MOUNTAINS AND DESERTS. ADDITIONAL COOLING IS EXPECTED
THROUGH THE MIDDLE OF THE WEEK AS A TROUGH OF LOW PRESSURE
INFLUENCES THE US WEST COAST. THE TROUGH OF LOW PRESSURE IS
EXPECTED TO APPROACH THE WEST COAST TUESDAY AND BE TO OUR EAST BY
WEDNESDAY EVENING. THIS LOW WILL BRING WIDESPREAD CLOUD COVERAGE,
INCREASE WINDS OVER THE MOUNTAINS AND DESERTS, AND AREAS OF LIGHT
PRECIPITATION.
SOUTHWEST TO WEST WINDS WILL BEGIN TO STRENGTHEN TUESDAY AFTERNOON,
PEAK IN STRENGTH OVERNIGHT, AND WEAKEN WEDNESDAY MORNING.
STRONGEST WINDS WILL BE OVER THE MOUNTAINS AND INTO THE DESERTS.
PEAK GUSTS OF 40 TO 60 MPH EXPECTED, WITH A FEW ISOLATED GUSTS TO
65 MPH ON THE NORTHERN SLOPES OF THE SAN BERNARDINO MOUNTAINS.
WINDS WILL DECREASE THROUGH THE DAY WEDNESDAY WITH GUSTS MAINLY 35
TO 45 MPH, LOCALLY UP TO 55 MPH THROUGH WIND PRONE PASSES LIKE
THE SAN GORGONIO PASS. PERIODS OF LIGHT PRECIPITATION ARE EXPECTED
TUESDAY EVENING INTO EARLY WEDNESDAY MORNING. THE FORECAST HAS
TRENDED DRIER, WITH THE MOST LIKELY PLACE FOR MEASURABLE
PRECIPITATION IN THE SAN BERNARDINO COUNTY MOUNTAINS. HOURLY
RAINFALL RATES ARE EXPECTED TO BE 0.10 INCH OR LESS.
DRY AND WARMER CONDITIONS EXPECTED ON THURSDAY. HIGHS ALONG THE
COAST WILL BE A FEW DEGREES WARMER, WITH INLAND LOCATIONS UP TO 7
DEGREES WARMER THAN WEDNESDAY. THE TEMPERATURE INCREASE WILL BRING
CONDITIONS NEAR TO SLIGHTLY ABOVE NORMAL FOR THIS TIME OF YEAR.
ANOTHER AREA OF LOW PRESSURE LOOKS LIKELY TO MOVE ACROSS THE US WEST
COAST FOR THE UPCOMING WEEKEND. WHILE THERE REMAINS SOME TIMING
DIFFERENCES BETWEEN THE GLOBAL MODELS, THE TROUGH WILL BRING ANOTHER
ROUND OF COOLER CONDITIONS, INCREASE IN WESTERLY WINDS, AND
POTENTIAL FOR LIGHT PRECIPITATION.
AVIATION
210000Z...COAST/VALLEYS...PATCHY LOW CLOUDS 1800-2500 FT MSL WILL
GRADUALLY DEVELOP AND EXPAND AFTER 05Z TONIGHT INTO TUESDAY, WITH
SIMILAR AREAL EXTENT TO THIS MORNING AND NON-UNIFORM COVERAGE.
CONDITIONS WILL BOUNCE BETWEEN VFR AND MVFR MOST OF THE NIGHT. LOW
CLOUDS CLEAR 14-17Z TUE MORNING. A BAND OF LOW CLOUDS BASED 1500-
2500 FT MSL ASSOCIATED WITH A WEAK FRONT WILL MOVE FROM WEST TO EAST
ACROSS THE COASTAL BASIN STARTING AROUND 21Z TUE. ISO -SHRA MAY
BRIEFLY CREATE MVFR VIS TUESDAY EVENING.
MOUNTAINS/DESERTS...WEST TO WEST-SOUTHWEST WINDS WILL REMAIN
ELEVATED THROUGH MOUNTAIN PASSES, ALONG DESERT SLOPES AND LOCALLY
INTO DESERTS THROUGH THIS EVENING. STRONGEST WINDS WILL GUST 25-35
KNOTS PRODUCING MODERATE UP/DOWNDRAFTS IN LEE OF MOUNTAINS. WINDS
SLOWLY DIMINISH AFTER 06Z TUE. WINDS PICK UP AGAIN OUT OF THE
SOUTHWEST ON TUESDAY, BECOMING STRONG AFTER 21Z. WIDESPREAD GUSTS 35-
45 KTS EXPECTED WITH GUSTS LOCALLY TO 55 KTS ALONG DESERT SLOPES AND
THROUGH MOUNTAIN PASSES. AREAS BLDU IN THE DESERTS AND
MODERATE/STRONG UP/DOWNDRAFTS IN LEE OF MTNS.
MARINE
WESTERLY WINDS WILL INCREASE WEDNESDAY AFTERNOON WITH GUSTS 20-25
KNOTS LIKELY FOR OUTER COASTAL WATERS. THIS MAY GENERATE HAZARDOUS
CONDITIONS FOR SMALL CRAFT WEDNESDAY EVENING INTO EARLY THURSDAY
MORNING. OTHERWISE, NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED
THROUGH FRIDAY.
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 TUESDAY TO 7 AM PDT WEDNESDAY FOR APPLE
AND LUCERNE VALLEYS-RIVERSIDE COUNTY MOUNTAINS-SAN
BERNARDINO COUNTY MOUNTAINS-SAN DIEGO COUNTY DESERTS-SAN
DIEGO COUNTY MOUNTAINS-SAN GORGONIO PASS NEAR BANNING.
PZ...NONE.
PUBLIC...CO
AVIATION/MARINE...KW
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