519
FXUS66 KSGX 060611
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
1111 PM PDT WED AUG 5 2026
SYNOPSIS
INCREASED HEATRISK EXPECTED THROUGH SATURDAY WITH MODERATE HEATRISK
FOR THE MOUNTAINS AND INLAND EMPIRE WITH MAJOR TO EXTREME HEATRISK
IN THE DESERTS. THERE IS A CHANCE OF SHOWERS AND ISOLATED
THUNDERSTORMS IN THE MOUNTAINS EACH AFTERNOON THROUGH TUESDAY.
COASTAL AREAS WILL CONTINUE TO SEE LOW CLOUDS EACH NIGHT AND MORNING
THROUGH THE FORECAST PERIOD.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
..UPDATED AVIATION DISCUSSION
VISIBLE SATELLITE AT 11 AM WAS SHOWING MARINE LAYER LOW CLOUDS
SLOWLY CLEARING FROM THE COAST. THE INVERSION ON THE 12Z KNKX
SOUNDING WAS ABOUT 10 DEGREES SO CLEARING AT THE BEACHES THIS
AFTERNOON MAY BE PATCHY. LOW CLOUDS WILL REMAIN CONSTANT AT THE
COAST EACH NIGHT AND MORNING THROUGH THE FORECAST PERIOD, REACHING
INTO PORTIONS OF THE WESTERN VALLEYS AT TIMES.
THURSDAY THROUGH SATURDAY HIGHS WILL BE ABOVE AVERAGE NEAR THE COAST
TO 5 TO LOCALLY 10 DEGREES ABOVE AVERAGE FOR SOME INLAND AREAS. LOW
TEMPERATURES WILL ALSO RUN ABOVE AVERAGE, MOST NOTICEABLE IN THE
MOUNTAINS AND DESERTS WHERE LOWS WILL BE 10 TO 15 DEGREES ABOVE
AVERAGE. FOR THE INLAND EMPIRE AND MOUNTAINS, WIDESPREAD MODERATE
HEATRISK IS EXPECTED WHICH MEANS THAT FOLKS WHO ARE SENSITIVE HEAT,
ESPECIALLY THOSE WITHOUT CONSISTENT COOLING/HYDRATION WILL BE MOST
IMPACTED. IN THE DESERTS, MAJOR TO LOCALLY EXTREME HEATRISK
INDICATES ANYONE MAY SEE NEGATIVE IMPACTS FROM THE HEAT IF
PRECAUTIONS AREN'T TAKEN. MAKE SURE TO STAY HYDRATED AND IF POSSIBLE
AVOID STRENUOUS ACTIVITY DURING THE HOTTEST PARTS OF THE DAY (10 AM
TO 4 PM).
THE FLOW ALOFT WILL TURN SOUTHEASTERLY THURSDAY AND REMAIN
SOUTHEASTERLY INTO EARLY NEXT WEEK. THIS WOULD ALLOW FOR SOME
MONSOONAL MOISTURE INTO THE AREA AND BRING A 15 TO 20 PERCENT CHANCE
OF SHOWERS AND ISOLATED THUNDERSTORMS TO THE MOUNTAINS EACH
AFTERNOON. THROUGH FRIDAY, THERE IS ONLY A 15 PERCENT CHANCE OF
RAINFALL RATES EXCEEDING 0.50" PER HOUR IN ANY SHOWERS THAT DEVELOP
IN THE MOUNTAINS. CURRENT FORECAST FOLLOWS THE NBM WHICH HAS CHANCES
EACH AFTERNOON, WITH MOST WIDESPREAD COVERAGE SUNDAY AND MONDAY.
AVIATION
060600Z....COASTS/VALLEYS...AREAS OF LOW CLOUDS BASED 1200-1700 FT
MSL HAVE DEVELOPED OVER COASTAL AREAS LATE THIS EVENING.
INTERMITTENT CIGS AT COASTAL TAF SITES SHOULD BECOME MORE PERSISTENT
BY 12Z THU AS THE LOW CLOUD LAYER SLOWLY BECOMES MORE UNIFORM
OVERNIGHT. CLOUDS MAY REACH UP TO 20 MILES INLAND THURSDAY MORNING
BEFORE SCATTERING BACK TO THE COASTLINE BY 16Z. VFR CONDITIONS
EXPECTED THURSDAY AFTERNOON AND EVENING WITH LOW CHANCES FOR ANY
CIGS BEFORE 06Z FRI. THEREAFTER, CLOUDS WILL SLOWLY DEVELOP OVER
COASTAL AREAS WITH SLIGHTLY LOWER BASES AND PATCHIER COVERAGE THAN
TONIGHT.
MOUNTAINS/DESERTS
ISO SHRA/TSRA (10% CHANCE) MAY DEVELOP ALONG
MTN RIDGES 20-23Z THU. OTHERWISE, SCT-BKN CLOUDS AOA 20,000FT MSL
WITH UNRESTRICTED VIS THROUGH THURSDAY EVENING.
MARINE
NO HAZARDOUS MARINE CONDITIONS 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...HEAT ADVISORY UNTIL 8 PM PDT SATURDAY FOR RIVERSIDE COUNTY
MOUNTAINS-SAN BERNARDINO COUNTY MOUNTAINS-SAN BERNARDINO
AND RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE-SAN DIEGO
COUNTY MOUNTAINS.
EXTREME HEAT WARNING UNTIL 8 PM PDT SATURDAY FOR APPLE AND
LUCERNE VALLEYS-COACHELLA VALLEY-SAN DIEGO COUNTY DESERTS-
SAN GORGONIO PASS NEAR BANNING.
PZ...NONE.
PUBLIC...CO
AVIATION/MARINE...KW
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