894
FXUS66 KSGX 060908
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
208 AM PDT THU AUG 6 2026
SYNOPSIS
THE HEATRISK WILL CONTINUE TO SLOWLY INCREASE THROUGH SATURDAY
WITH WIDESPREAD MAJOR HEATRISK FOR THE DESERTS AND WIDESPREAD
MODERATE HEATRISK FOR INLAND EMPIRE AND FOR THE MOUNTAINS BELOW
6500 FEET. THERE WILL BE A SLIGHT CHANCE OF AFTERNOON SHOWERS AND
THUNDERSTORMS FOR THE MOUNTAINS THROUGH NEXT TUESDAY WITH THE
RELATIVELY GREATER CHANCES FOR THIS AFTERNOON AND AGAIN FOR SUNDAY
THROUGH TUESDAY. GRADUAL COOLING AND DRYING WILL THEN FOLLOW FOR
THE REST OF NEXT WEEK.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
SHORT TERM (TODAY THROUGH SATURDAY)
ENSEMBLE OUTPUT SHOWS PRECIPITABLE WATER VALUES PEAKING THIS
AFTERNOON, THEN DECLINING INTO SATURDAY AFTERNOON. THE PEAK HOURLY REFS
90TH PERCENTILE RAINFALL IS AROUND 0.75 INCH FOR THIS AFTERNOON
AND AROUND 0.25 INCH FOR FRIDAY AFTERNOON. THERE IS A SLIGHT
CHANCE OF SHOWERS AND THUNDERSTORMS FOR THE MOUNTAINS FOR THIS
AFTERNOON WITH SLOWLY DECREASING CHANCES FOR FRIDAY AFTERNOON AND
SATURDAY AFTERNOON.
THE HEATRISK WILL CONTINUE TO SLOWLY INCREASE THROUGH SATURDAY
WITH WIDESPREAD MAJOR HEATRISK FOR THE DESERTS AND WIDESPREAD
MODERATE HEATRISK FOR INLAND EMPIRE AND FOR THE MOUNTAINS BELOW
6500 FEET. HIGH TEMPERATURES ON SATURDAY WILL BE A FEW DEGREES
ABOVE AVERAGE NEAR THE COAST TO 5 TO 10 DEGREES ABOVE AVERAGE FOR
THE DESERTS. HIGH TEMPERATURES ON SATURDAY WILL RANGE FROM THE MID
70S TO LOWER 80S NEAR THE COAST TO THE MID 90S TO 105 FOR THE
INLAND EMPIRE WITH 110 TO 114 FOR THE LOWER DESERTS.
NIGHT AND MORNING WILL CONTINUE TO SPREAD INTO COASTAL AREAS, BUT
WITH SOME OCCASIONAL DISRUPTIONS IN COVERAGE FROM MID LEVEL
MONSOONAL MOISTURE AND CLOUDS.
LONG TERM (SUNDAY THROUGH WEDNESDAY)
THE EXTREME HEAT WARNING FOR THE DESERTS AND HEAT ADVISORY FOR THE
MOUNTAINS AND INLAND EMPIRE HAS BEEN EXTENDED THROUGH SUNDAY WITH
ONLY A SLIGHT DECLINE IN HEATRISK ON SUNDAY. GREATER DECLINES ARE
EXPECTED FOR MONDAY AND TUESDAY WITH MODERATE HEATRISK FOR NEXT
TUESDAY CONFINED MOSTLY TO THE DESERTS.
ENSEMBLE OUTPUT SHOWS ANOTHER PEAK IN PRECIPITABLE WATER VALUES
FOR SUNDAY AFTERNOON, SIMILAR TO THE PEAK FOR THIS AFTERNOON, THEN
A GRADUAL SLOW DECLINE THROUGH NEXT WEEK. A SLIGHT CHANCE FOR
AFTERNOON SHOWERS AND THUNDERSTORMS FOR THE MOUNTAINS WILL
CONTINUE FOR SUNDAY THROUGH TUESDAY WITH GRADUAL COOLING AND
DRYING FOR THE REST OF NEXT WEEK. FOR THURSDAY OF NEXT WEEK, HIGH
TEMPERATURES FOR THE DESERTS AND NEAR THE COAST WILL BE AROUND
AVERAGE AND COULD BE AS MUCH AS 4 TO 8 DEGREES BELOW AVERAGE FOR
THE INLAND VALLEYS. FOR THURSDAY OF NEXT WEEK, HIGH TEMPERATURES
COULD RANGE FROM THE 70S NEAR THE COAST TO THE MID 80S TO MID 90S
FOR THE INLAND EMPIRE WITH 106 TO 110 FOR THE LOWER DESERTS.
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 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...17
AVIATION/MARINE...KW
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