088
FXUS66 KSGX 270429
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
929 PM PDT TUE AUG 26 2025
SYNOPSIS
THERE IS A 20-35 PERCENT CHANCE OF STORMS OVER THE MOUNTAINS AND
LOCALLY INTO THE DESERTS WEDNESDAY AFTERNOON. MID AND HIGH LEVEL
MOISTURE FROM THE REMNANTS OF TROPICAL STORM JULIETTE COULD BRING
SOME SCATTERED SHOWERS AND ON THURSDAY TO MUCH OF THE REGION. A
DRYING AND WARMING TREND WILL OCCUR BY THE END OF THIS WEEK WITH
MINOR COOLING EARLY NEXT WEEK.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
EVENING UPDATE...
ANOTHER FAIRLY ACTIVE MONSOON DAY HAS COME TO AN END WITH JUST
SOME RESIDUAL MID-LEVEL CLOUDS LEFT. PATCHY LOW CLOUDS HAVE BEGUN
TO DEVELOP ALONG THE COAST AND SHOULD FILL IN AND SPREAD INTO THE
FAR WESTERN VALLEYS OVERNIGHT. ANOTHER ROUND OF AFTERNOON SHOWERS
AND THUNDERSTORMS IS EXPECTED ON WEDNESDAY, PREDOMINANTLY OVER THE
MOUNTAINS. WITH DECREASING MOISTURE, RAIN RATES SHOULD BE LOWER
THAN TODAY, GENERALLY PEAKING AT AROUND 0.50"/HR IN THE STRONGEST
STORMS. COVERAGE WILL ALSO BE LESS WIDESPREAD THAN TODAY.
PREVIOUS DISCUSSION...
AN INTERESTING FORECAST UNFOLDS BY WEDNESDAY NIGHT INTO THURSDAY
AS REMNANTS FROM TROPICAL STORM JULIETTE MOVES NORTH PARALLEL TO
THE BAJA CALIFORNIA COAST. THIS WILL BRING IN HIGH CLOUDS TO
ACROSS THE REGION. FORECAST SOUNDINGS AND MODEL DATA SHOW A MOIST
ATMOSPHERIC PROFILE, THOUGH THE LOWER THIRD OF THE ATMOSPHERE HAS
ADEQUATE T/TD SPREAD, SHOWING DRIER AIR NEAR THE SURFACE. THE
BEST CHANCES FOR RAINFALL TO REACH THE GROUND WILL BE PLACES
ACROSS SAN DIEGO COUNTY, WHERE ENSEMBLE MODEL MEMBERS ARE SHOWING
SOME LIGHT PRECIP AMOUNTS. LIGHT SHOWERS WILL BE POSSIBLE ACROSS
MUCH OF THE AREA, MINUS THE HIGH DESERT. THURSDAY WILL SEE MOSTLY
CLOUDY SKIES FOR MUCH OF THE REGION AS THE TROPICAL MOISTURE MOVES
IN, SO THIS WILL BE THE COOLEST DAY OF THE WEEK WITH SOME PLACES
ACROSS THE LOWER DESERTS STAYING BELOW 100 DEGREES.
HIGH PRESSURE OVER THE DESERT SOUTHWEST WILL PUSH SOUTHWARD INTO
NORTHERN MEXICO BY FRIDAY AS A WEAK TROUGHING PATTERN SETS UP
ACROSS CALIFORNIA. PWATS LOWER WITH MINOR INSTABILITY PRESENT, SO
ANY STORMS THAT FORM WOULD DO SO OVER THE MOUNTAINS WITH A 15-25%
CHANCE OF OCCURRENCE. FURTHER DRYING IS EXPECTED BY FRIDAY INTO
THE WEEKEND WITH MINIMAL CHANCES FOR STORMS ACROSS THE REGION. THE
AREA OF HIGH PRESSURE OF NORTHERN MEXICO WILL ALSO BEGIN TO EXPAND
WESTWARD, WHERE SOUTHERN CALIFORNIA WILL SEE A SUBTLE WARMING
TREND WITH LOWER HUMIDITY BY THE END OF THE WEEK.
AVIATION
270300Z...COAST/WESTERN VALLEYS...ISOLATED LOW CLOUDS 1000-1300
FT MSL ALONG THE IMMEDIATE COAST WILL START TO BECOME MORE
WIDESPREAD AND MOVE INLAND AFTER 05Z THIS EVENING, TO ABOUT 10
MILES INLAND OVERNIGHT. RESTRICTED VIS 2-5 SM FOR HIGHER TERRAIN
IN WESTERN VALLEYS. CLOUDS CLEAR BACK TO BEACHES 15-17Z WED
MORNING. SLIGHTLY LOWER CLOUDS AROUND 800-1100 FT MSL FORMING
AFTER 28/03Z BUT WILL LIKELY BE MUCH PATCHIER THAN TONIGHT.
MOUNTAINS/DESERTS...ISOLATED SHRA/TSRA WED 19-01Z WITH CB BASES
AROUND 10-12 KFT, MOSTLY CONFINED TO THE MOUNTAINS WITH SLIGHT
CHANCES IN THE LOW DESERT AND NORTHEASTERN HIGH DESERT. GUSTY AND
ERRATIC WINDS OF 35 KTS, PERIODS OF LOWER VIS 2-5 SM IN HEAVIER
SHOWERS, AND LIGHTNING ARE POSSIBLE.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH 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...SS/APR
AVIATION/MARINE...CSP
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