600
FXUS66 KSGX 061823
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
1123 AM PDT THU AUG 6 2026
SYNOPSIS
THROUGH SUNDAY MODERATE HEATRISK EXPECTED IN THE MOUNTAINS AND
INLAND EMPIRE WITH MAJOR TO EXTREME HEATRISK IN THE DESERTS. THERE
ARE CHANCES 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...
VISIBLE SATELLITE AT 11 AM WAS SHOWING AREAS OF HIGH CLOUDS ACROSS
THE AREA WITH LOW CLOUDS OFF THE COAST. THERE REMAIN CHANCES OF
ISOLATED SHOWERS AND THUNDERSTORMS IN THE MOUNTAINS THIS AFTERNOON.
LATEST REFS GUIDANCE INDICATES A DECREASE IN THE 90TH PERCENTILE
MAXIMUM HOURLY RAINFALL RATE THIS AFTERNOON, DOWN TO 0.45 INCHES PER
HOUR. THERE IS ONLY A 10 PERCENT CHANCE OF HOURLY RAINFALL RATES
EXCEEDING THAT. GUIDANCE CONTINUES TO INDICATE 15-20 PERCENT
CHANCE OF ISOLATED SHOWERS AND THUNDERSTORMS OVER AREA MOUNTAINS
THROUGH SATURDAY, WITH GUIDANCE INDICATING HOURLY RAINFALL RATES
WILL BE LESS THAN 0.50 INCH PER HOUR.
THROUGH SUNDAY HIGH TEMPERATURES ARE EXPECTED TO RUN 5 TO 10 DEGREES
ABOVE AVERAGE FOR 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,
MOUNTAINS, AND PORTIONS OF INLAND ORANGE COUNTY AND SAN DIEGO
VALLEYS 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
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). HIGH TEMPERATURES ARE EXPECTED TO GRADUALLY DECREASE NEXT
WEEK, BRINGING TEMPERATURES BACK DOWN TO NEAR OR SLIGHTLY BELOW
AVERAGE BY THE MIDDLE OF NEXT WEEK.
FOR SUNDAY AND MONDAY, PRECIPITABLE WATER VALUES ARE EXPECTED TO
PEAK WHICH WILL RESULT IN MORE WIDESPREAD SHOWER AND THUNDERSTORM
CHANCES ACROSS THE MOUNTAINS. SHOWER CHANCES WILL BECOME MORE
ISOLATED AGAIN TUESDAY AND WEDNESDAY.
AVIATION
061800Z....COASTS/VALLEYS...SATELLITE SHOWS LOW CLOUDS HAVE CLEARED
THE COAST WITH FEW-SCT HIGH CLOUDS AOA 20,000FT MSL MOVING IN FROM
THE SOUTH. VFR THROUGH THE REMAINDER OF THE AFTERNOON. PATCHY LOW
CLOUDS BASED 800-1200FT MSL TONIGHT DEVELOP AND MOVE INLAND LIKELY
AFTER 03Z FRI, SPREADING NORTH INTO ORANGE COUNTY AFTER 07Z. 50%
CHANCE OF A BRIEF CIG AT KCRQ. VIS POTENTIALLY DOWN TO 3-5SM FOR
VALLEYS AND COASTAL TERRAIN. CLEARING OUT ON FRIDAY SHOULD OCCUR AT
A SIMILAR PACE TO THIS MORNING, AROUND 16-18Z.
MOUNTAINS/DESERTS
ISO SHRA/TSRA (15% CHANCE) MAY DEVELOP ALONG
MTN RIDGES 20-23Z. OTHERWISE, FEW-SCT CU AOA 20,000FT MSL WITH
UNRESTRICTED VIS INTO FRIDAY.
MARINE
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...HEAT ADVISORY UNTIL 8 PM PDT SUNDAY 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 SUNDAY FOR APPLE AND LUCERNE
VALLEYS-COACHELLA VALLEY-SAN DIEGO COUNTY DESERTS-SAN
GORGONIO PASS NEAR BANNING.
PZ...NONE.
PUBLIC...CO
AVIATION/MARINE...ZUBER
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