854
FXUS66 KSGX 281624
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
924 AM PDT THU AUG 28 2025
SYNOPSIS
MOISTURE FROM THE REMNANTS OF TROPICAL STORM JULIETTE WILL BRING
MORE CLOUDS AND COOLER HIGH TEMPERATURES TODAY WITH GREATER
CHANCES FOR SHOWERS TO THE SOUTH WITH LESSER CHANCES TO THE
NORTH. THERE IS ALSO A SLIGHT CHANCE OF THUNDERSTORMS FOR THIS
AFTERNOON. THERE WILL BE DRYING AND WARMING FOR FRIDAY THROUGH
SUNDAY. MONSOONAL MOISTURE MAY BEGIN TO RETURN FOR NEXT WEEK WITH
THE GREATER CHANCES FOR AFTERNOON THUNDERSTORMS FOR TUESDAY
THROUGH THURSDAY.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
MORNING UPDATE
HIGH CLOUDS AND LIGHT SHOWERS HAVE COVERED PORTIONS OF SOUTHERN
CALIFORNIA THIS MORNING FROM POST TROPICAL CYCLONE JULIETTE.
CONGRATS TO SAN DIEGO...THE AIRPORT HAS RECEIVED 0.03" THUS FAR,
PUSHING OVER THE AVERAGE MONTHLY RAINFALL (A RESOUNDING 0.01").
THIS MORNING'S SOUNDING SHOWS A MOIST PROFILE IN THE MID LEVELS
WITH PWAT VALUES OVER 1.50". LIGHT SHOWERS WILL CONTINUE THROUGH
EARLY EVENING. I AGREE WITH MY COLLEAGUE'S THOUGHTS BELOW ON
MOSTLY SHOWERS OCCURRING WITH A SMALL CHANCE OF THUNDERSTORMS BY
THIS AFTERNOON. MOSTLY DRY FOR FRIDAY INTO THE WEEKEND FOR THE
ENTIRE REGION WITH INCREASING CHANCES FOR STORMS TO RETURN TO THE
MOUNTAINS AND DESERTS BY MONDAY ONWARD.
PREVIOUS DISCUSSION (334 AM THURSDAY)
SHORT TERM (TODAY THROUGH SATURDAY)
MOISTURE FROM THE REMNANTS OF TROPICAL STORM JULIETTE WILL BRING
MORE CLOUDS AND COOLER HIGH TEMPERATURES TODAY WITH THE GREATER
CHANCES FOR MEASURABLE RAINFALL TO THE SOUTH AND LESS TOWARD THE
NORTH. THE DEPTH OF THE SATURATED LAYER WITH MID AND HIGH CLOUDS
EXTENDS DOWN TO AROUND 10 THOUSAND FEET. THIS MAY EVENTUALLY
EXTEND DOWN TO AROUND 5000 FEET AS RAIN FALLING FROM MID LEVEL
CLOUD BASES GRADUALLY SATURATES THE DRIER LAYER BELOW.
AS THE SATURATED LAYER GRADUALLY LOWERS, LIGHT TO LOCALLY
MODERATE RAINFALL COULD DEVELOP THIS MORNING WITH THE GREATEST
COVERAGE OVER RIVERSIDE AND SAN DIEGO COUNTIES AND MORE ISOLATED
SHOWERS NORTHWARD. HIGHER RESOLUTION GUIDANCE SHOWS RAINFALL RATES
MOSTLY 0.10 INCH PER HOUR OR LESS, THOUGH AS THE REMNANT UPPER
LOW MOVES NORTHWARD INTO THE AREA TODAY, THERE COULD BE ENOUGH
LIFT AND WEAK ELEVATED INSTABILITY TO PRODUCE LOCAL RAINFALL RATES
OF 0.25 TO 0.5 INCH PER HOUR. THERE IS A SLIGHT CHANCE OF
THUNDERSTORMS FOR THIS AFTERNOON. IF THERE ARE ENOUGH BREAKS IN
THE OVERCAST, THUNDERSTORMS CAPABLE OF PRODUCING ISOLATED FLASH
FLOODING COULD OCCUR OVER THE RIVERSIDE COUNTY MOUNTAINS AND SAN
BERNARDINO MOUNTAINS.
IT WILL BE COOLER TODAY WITH HIGH TEMPERATURES 10 TO 15 DEGREES
BELOW AVERAGE FOR THE MOUNTAINS AND DESERTS WITH HIGH TEMPERATURES
RANGING FROM THE MID 70S TO LOWER 80S NEAR THE COAST TO THE 80S TO
AROUND 90 FOR THE INLAND EMPIRE WITH HIGH TEMPERATURES MOSTLY IN
THE LOWER 90S FOR THE LOWER DESERTS.
THERE WILL BE DRYING AND WARMING FOR FRIDAY THROUGH THE WEEKEND
WITH SATURDAY HIGH TEMPERATURES A FEW DEGREES BELOW AVERAGE,
RANGING FROM THE MID 70S LOWER 80S NEAR THE COAST TO THE 90S FOR
THE INLAND EMPIRE WITH 104 TO 108 FOR THE LOWER DESERTS.
LONG TERM (SUNDAY THROUGH WEDNESDAY)
DRYING AND WARMING WILL CONTINUE INTO SUNDAY WITH SUNDAY HIGH
TEMPERATURES WITHIN A FEW DEGREES OF AVERAGE FOR MOST AREAS. HIGH
TEMPERATURES ON SUNDAY WILL RANGE FROM THE MID 70S TO LOWER 80S
NEAR THE COAST TO THE 90S TO AROUND 100 FOR THE INLAND EMPIRE
WITH 106 TO 110 FOR THE LOWER DESERTS.
MONSOONAL MOISTURE MAY BEGIN TO INCREASE FOR THE EARLY AND MIDDLE
PART OF NEXT WEEK WITH SOUTH TO SOUTHEAST FLOW ALOFT BETWEEN A
WEAK LOW PRESSURE SYSTEM NEAR THE CALIFORNIA COAST AND HIGH
PRESSURE TO THE EAST. CHANCES FOR AFTERNOON AND EARLY EVENING
SHOWERS AND THUNDERSTORMS FOR THE MOUNTAINS AND DESERTS WILL
INCREASE TO 20 TO 30 PERCENT FOR TUESDAY THROUGH THURSDAY.
AVIATION
281610Z...WIDESPREAD CLOUDS AT OR ABOVE 10000 FEET MSL THROUGH
TODAY, DECREASING EARLY FRIDAY. A FEW PATCHES OF COASTAL LOW CLOUDS
VCNTY COASTAL TAF SITES WITH BASES AROUND 1000 FEET MSL. PERIODS OF
CIG IMPACTS ARE POSSIBLE WITH PROBABILITIES <40 PERCENT THROUGH 08Z
FRIDAY. CHANCES OF -RA, PEAKING THIS AFTERNOON, AND DECREASING THIS
EVENING. THERE IS ALSO A SLIGHT CHANCE OF TSRA 19-00Z, WITH GUSTY
WINDS NEAR ANY STORMS THAT MAY FORM. RAIN AND THUNDERSTORM CHANCES
ARE GREATEST IN SOUTHERN AND EASTERN PARTS OF THE REGION. HIGH
CLOUDS WILL EVENTUALLY THIN AND SCATTER FRIDAY MORNING.
MARINE
THERE IS A SLIGHT CHANCE OF THUNDERSTORMS THIS AFTERNOON. ANY
THUNDERSTORMS THAT FORM COULD PRODUCE GUSTY, ERRATIC WINDS LEADING
TO LOCALLY ROUGH SEAS, ALONG WITH LIGHTNING AND SMALL HAIL.
OTHERWISE, NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH
MONDAY.
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/17
AVIATION/MARINE...PG
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