933
FXUS66 KSGX 250957
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
257 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...
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
250600Z...COAST...PATCHY LOW CLOUDS 400-700 FT MSL EXPECTED TO
DEVELOP OVERNIGHT, MOST LIKELY TO IMPACT KSAN AND KCRQ AFTER 12Z.
LOW CONFIDENCE IN CIGS REACHING KSNA. VIS REDUCTIONS 0-5 SM POSSIBLE
WHERE CIGS FORM. ANY CIGS AND VIS RESTRICTIONS WILL CLEAR AROUND
15Z. PATCHY LOW CLOUDS WILL FORM AGAIN AFTER 01-03Z ALONG THE
COASTAL AREAS, MAINLY FOR SOUTHERN SAN DIEGO COUNTY, WITH CIGS
AROUND 800-1500 MSL, OCCASIONALLY GOING BROKEN THROUGHOUT THE REST
OF THE FORECAST PERIOD.
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 POSSIBLE TUESDAY AFTERNOON. ANY TS
COULD PRODUCE GUSTY, ERRATIC WINDS.
OTHERWISE...SCT TO LOCALLY BKN CLOUDS AOA 10-15 KFEET MSL BECOMING
MOSTLY CLEAR AFTER 03Z. SIMILAR CLOUD COVER TUE AFTER 18Z.
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. BREAKING WAVES OF 4 TO 6 FEET EXPECTED, SETS UP TO 8 FEET
POSSIBLE AT BEACHES THAT FACE DUE SOUTH. SURF GRADUALLY SUBSIDES ON
FRIDAY.
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 TUESDAY TO 8 PM PDT FRIDAY FOR ORANGE
COUNTY COASTAL AREAS-SAN DIEGO COUNTY COASTAL AREAS.
HEAT ADVISORY UNTIL 10 AM PDT TUESDAY FOR ORANGE COUNTY INLAND
AREAS-SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE
INLAND EMPIRE-SAN DIEGO COUNTY MOUNTAINS-SAN DIEGO COUNTY
VALLEYS-SANTA ANA MOUNTAINS AND FOOTHILLS.
EXTREME HEAT WARNING FROM 10 AM TUESDAY TO 8 PM PDT FRIDAY FOR
APPLE AND LUCERNE VALLEYS-ORANGE COUNTY INLAND AREAS-SAN
BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE-
SAN DIEGO COUNTY MOUNTAINS-SAN DIEGO COUNTY VALLEYS-SANTA
ANA MOUNTAINS AND FOOTHILLS.
HEAT ADVISORY UNTIL 8 PM PDT FRIDAY FOR RIVERSIDE COUNTY
MOUNTAINS-SAN BERNARDINO COUNTY MOUNTAINS.
EXTREME HEAT WARNING UNTIL 8 PM PDT FRIDAY FOR COACHELLA VALLEY-
SAN DIEGO COUNTY DESERTS-SAN GORGONIO PASS NEAR BANNING.
PZ...NONE.
PUBLIC...17
AVIATION/MARINE/BEACHES...MM
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