208
FXUS66 KSGX 251133
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
433 AM PDT TUE AUG 25 2026
SYNOPSIS
A SLIGHT CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS WILL
CONTINUE FOR THE MOUNTAINS THROUGH WEDNESDAY AS MONSOONAL MOISTURE
SLOWLY DECREASES. HIGH AND LOW TEMPERATURES WILL CONTINUE TO WARM
THROUGH THURSDAY, TO AS MUCH AS 10 TO 15 DEGREES ABOVE AVERAGE,
WITH NOT MUCH CHANGE FOR FRIDAY. THE HIGHEST HEATRISK IS EXPECTED
FOR THURSDAY AND FRIDAY WITH WIDESPREAD EXTREME HEATRISK FOR THE
INLAND VALLEYS AND INLAND ORANGE COUNTY. THIS WILL BE FOLLOWED BY
A COOLING TREND FOR THE WEEKEND INTO EARLY NEXT WEEK WITH
STRONGER ONSHORE FLOW AND DRIER SOUTHWEST FLOW ALOFT WITH HIGH
TEMPERATURES FALLING TO AROUND AVERAGE FOR NEXT MONDAY.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
..UPDATED AVIATION DISCUSSION
SHORT TERM (TODAY THROUGH THURSDAY)
THE WARMING TREND WILL CONTINUE THROUGH THURSDAY WITH WARMER DAYS
AND WARMER NIGHTS. HIGH TEMPERATURES ON THURSDAY WILL RANGE FROM
THE 80S NEAR THE COAST TO 106 TO 112 FOR THE INLAND EMPIRE WITH
110 TO 116 FOR THE LOWER DESERTS. LOW TEMPERATURES ON THURSDAY
WILL BE MOSTLY IN THE 70S FOR THE COAST AND VALLEYS AND IN THE
MID 80S TO MID 90S FOR THE LOWER DESERTS.
THE HIGHEST HEATRISK FOR THE COAST AND VALLEYS IS EXPECTED ON
THURSDAY AND FRIDAY WITH WIDESPREAD EXTREME HEATRISK FOR THE
INLAND VALLEYS AND INLAND ORANGE COUNTY WITH MAJOR HEATRISK FOR
MOST OTHER AREAS WITH MODERATE HEATRISK LIMITED TO THE BEACHES.
MID LEVEL MONSOONAL MOISTURE WILL REMAIN IN PLACE TODAY WITH A
SLIGHT DECREASE ON WEDNESDAY AND A GREATER DECREASE ON THURSDAY. A
SLIGHT CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS, MOSTLY FOR
THE MOUNTAINS, WILL CONTINUE THROUGH WEDNESDAY.
LONG TERM (FRIDAY THROUGH MONDAY)
FOR SATURDAY THROUGH MONDAY, HIGH PRESSURE WILL BEGIN TO WEAKEN
ACROSS THE AREA AS A LOW PRESSURE SYSTEM DEVELOPS NEAR THE
CALIFORNIA COAST, STRENGTHENING ONSHORE LOWER LEVEL FLOW. HIGH
TEMPERATURES WILL FALL TO AROUND 5 DEGREES ABOVE AVERAGE ON SUNDAY
AND A FEW DEGREES BELOW AVERAGE FOR THE MOUNTAINS AND INLAND
VALLEYS ON MONDAY. MONDAY HIGH TEMPERATURES WILL RANGE FROM THE
MID 70S TO LOWER 80S NEAR THE COAST TO THE 90S FOR THE INLAND
EMPIRE WITH 104 TO 108 FOR THE LOWER DESERTS.
AVIATION
251130Z...COAST...PATCHY LOW CLOUDS 600-1000 FEET MSL WILL BE RANDOM
AND INTERMITTENT THROUGH 16Z. VIS REDUCTIONS 1-5SM POSSIBLE WHERE
CIGS FORM. PATCHY LOW CLOUDS WILL FORM AGAIN AFTER 03Z AND OVERNIGHT
INTO WEDNESDAY. ISOLATED AND RANDOM CIGS WOULD BE 600-1000 FEET MSL.
MOUNTAINS/DESERTS...CUMULUS BASED AROUND 9000 FEET MSL WITH CB
CLOUDS WITH TOPS TO 40000 FEET AND ISO TSRA OVER MOUNTAINS AND
LOCALLY INTO ADJACENT DESERTS 19-01Z. ANY TS COULD PRODUCE GUSTY,
ERRATIC WINDS.
OTHERWISE...SCT CLOUDS AOA 15000 FEET MSL.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH SATURDAY.
BEACHES
A 4-5 FOOT SOUTHERLY SWELL (FROM 170 DEGREES) AT 13-15 SECONDS WILL
MOVE INTO THE AREA WEDNESDAY AND THURSDAY, LEADING TO ELEVATED SURF
FOR THE SOUTH FACING BEACHES OF NORTHERN SAN DIEGO COUNTY AND ORANGE
COUNTY. SURF OF 3 TO 5 FEET, WITH SETS UP TO 7 FEET ARE EXPECTED.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...HEAT ADVISORY FROM 10 AM THIS MORNING TO 8 PM PDT FRIDAY FOR
ORANGE COUNTY COASTAL AREAS-SAN DIEGO COUNTY COASTAL AREAS.
EXTREME HEAT WARNING UNTIL 8 PM PDT FRIDAY FOR COACHELLA VALLEY-
ORANGE COUNTY INLAND AREAS-SAN BERNARDINO AND RIVERSIDE
COUNTY VALLEYS-THE INLAND EMPIRE-SAN DIEGO COUNTY DESERTS-
SAN DIEGO COUNTY MOUNTAINS-SAN DIEGO COUNTY VALLEYS-SAN
GORGONIO PASS NEAR BANNING-SANTA ANA MOUNTAINS AND
FOOTHILLS.
HEAT ADVISORY UNTIL 8 PM PDT FRIDAY FOR RIVERSIDE COUNTY
MOUNTAINS-SAN BERNARDINO COUNTY MOUNTAINS.
EXTREME HEAT WARNING FROM 10 AM THIS MORNING TO 8 PM PDT FRIDAY
FOR APPLE AND LUCERNE VALLEYS.
PZ...NONE.
PUBLIC...MARTIN
AVIATION/MARINE/BEACHES...MM
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