136
FXUS66 KSGX 161141
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
441 AM PDT TUE SEP 16 2025
SYNOPSIS
THE REMNANTS OF TROPICAL STORM MARIO WILL BRING INCREASING
MOISTURE AND CLOUDS FOR WEDNESDAY INTO THURSDAY ALONG WITH
INCREASING CHANCES FOR SHOWERS ALONG WITH A CHANCE FOR
THUNDERSTORMS. THERE WILL BE SOME DRYING FOR FRIDAY INTO THE
WEEKEND WITH CHANCES FOR THUNDERSTORMS MAINLY FOR THE MOUNTAINS
AND DESERTS EACH AFTERNOON AND EARLY EVENING. A SECOND TROPICAL
SYSTEM COULD BRING ANOTHER INCREASE IN MOISTURE FOR EARLY NEXT
WEEK.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
SHORT TERM (TODAY THROUGH THURSDAY)
SATELLITE IMAGERY SHOWS INCREASING COVERAGE OF LOW CLOUDS OVER THE
COASTAL WATERS, EXTENDING LOCALLY INLAND INTO COASTAL AREAS. FOG
COULD BE LOCALLY DENSE NEAR THE MESAS IN SAN DIEGO COUNTY AND NEAR
HIGHER TERRAIN FOR THE ORANGE COUNTY COASTAL PLAIN.
TODAY WILL BE WARMER WITH HIGH TEMPERATURES FOR THE COAST AND
VALLEYS AROUND 4 TO 8 DEGREES ABOVE AVERAGE WITH THE DESERTS A FEW
DEGREES ABOVE AVERAGE. HIGH TEMPERATURES WILL RANGE FROM AROUND
80 NEAR THE COAST TO THE MID 90S TO 102 FOR THE INLAND EMPIRE WITH
100 TO 105 FOR THE LOWER DESERTS.
THERE COULD BE SOME ISOLATED SHOWERS OR THUNDERSTORMS OVER THE
MOUNTAINS FOR THIS AFTERNOON WITH THE CHANCE FOR MEASURABLE
RAINFALL OF LESS THAN 15 PERCENT. THE REMNANTS OF TROPICAL STORM
MARIO WILL BRING INCREASING MOISTURE FOR WEDNESDAY INTO THURSDAY
ALONG WITH INCREASING CHANCES FOR SHOWERS ALONG WITH A CHANCE FOR
THUNDERSTORMS. THE MOISTURE IS EXPECTED TO PEAK ON THURSDAY ALONG
WITH CHANCES FOR SHOWERS. NBM CHANCES FOR ONE-HALF INCH OR MORE OF
RAINFALL IS AROUND 25 PERCENT FOR THE COAST AND VALLEYS TO AROUND
45 TO 55 PERCENT FOR THE MOUNTAINS.
WITH THE INCREASE IN MOISTURE AND CLOUDS, HIGH TEMPERATURES FOR
INLAND AREAS WILL COOL SEVERAL DEGREES FOR WEDNESDAY AND AGAIN ON
THURSDAY WITH HIGH TEMPERATURES ON THURSDAY AS MUCH AS 8 TO 12
DEGREES BELOW AVERAGE FOR THE MOUNTAINS WITH HIGH TEMPERATURES
RANGING FROM THE MID 70S NEAR THE COAST TO THE 80S FOR THE INLAND
EMPIRE WITH THE LOWER TO MID 90S FOR THE LOWER DESERTS.
LONG TERM (FRIDAY THROUGH MONDAY)
THE MOISTURE WILL DECREASE FOR FRIDAY INTO THE WEEKEND WITH
DECREASING CHANCES FOR THUNDERSTORMS, LIMITED MAINLY TO THE
MOUNTAINS AND DESERTS EACH AFTERNOON. THERE COULD BE ANOTHER
INFLUX OF TROPICAL MOISTURE EARLY NEXT WEEK FROM A SECOND TROPICAL
SYSTEM. HIGH TEMPERATURES FOR INLAND AREAS WILL WARM AROUND 10
DEGREES FROM THURSDAY THROUGH SUNDAY WITH SUNDAY HIGH TEMPERATURES
MOSTLY A FEW TO AROUND 5 DEGREES BELOW AVERAGE. HIGH TEMPERATURES
ON SUNDAY WILL RANGE FROM THE MID 70S NEAR THE COAST TO THE UPPER
80S TO MID 90S FOR THE INLAND EMPIRE WITH THE MID 90S TO AROUND
100 FOR THE LOWER DESERTS.
AVIATION
160930Z...COAST...LOW CLOUDS BASED 400-900 FEET MSL WILL CONTINUE TO
COVER MOST COASTAL AREAS THROUGH SUNRISE. AREAS VIS 1-5SM IN BR,
ESPECIALLY AROUND KSNA. SCATTER OUT TO HAPPEN BY 16Z. LOW CLOUDS
GENERALLY NOT EXPECTED TONIGHT INTO WEDNESDAY, JUST VERY PATCHY,
ISOLD CLOUDS WITH BASES 300-700 FEET MSL.
VALLEYS/MOUNTAINS/DESERTS...VFR CONDITIONS TODAY AND TONIGHT. CLOUDS
OVER MOUNTAINS DEVELOPING AFTER 18Z AND LEADING TO A SLIGHT CHANCE
TSRA 21-01Z. CB BASES AOA 10000 FEET MSL, WITH TOPS REACHING 30000
FEET MSL. LIGHTNING, GUSTY WINDS, AND REDUCED VIS EXPECTED WHERE ANY
TSRA DEVELOPS.
REGIONWIDE...SCT TO LOCALLY BKN CLOUDS AROUND 10000 FEET MSL
INCREASING AFTER 00Z.
MARINE
THERE IS A SLIGHT CHANCE OF THUNDERSTORMS WEDNESDAY THROUGH
FRIDAY, WITH A BETTER CHANCE THURSDAY AFTERNOON AND EVENING. ANY
STORMS COULD BRIEFLY PRODUCE LIGHTNING, GUSTY WINDS AND CHOPPY
SEAS. OTHERWISE, NO ADDITIONAL MARINE WEATHER HAZARDS ARE EXPECTED
THROUGH SATURDAY.
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...17
AVIATION/MARINE...MM
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