691
FXUS66 KSGX 080800
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
100 AM PDT SAT AUG 8 2026
SYNOPSIS
THROUGH SUNDAY MODERATE HEATRISK EXPECTED FOR THE INLAND VALLEYS AND
MOUNTAINS WITH MAJOR HEATRISK IN THE DESERTS. THE HEATRISK
DECREASES THROUGH NEXT WEEK. THERE ARE CHANCES OF SHOWERS AND
THUNDERSTORMS IN THE MOUNTAINS AND DESERTS EACH AFTERNOON THROUGH
TUESDAY. THERE ARE LOWER CHANCES TODAY WITH INCREASED THUNDERSTORM
CHANCES EARLY NEXT WEEK. 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...
THIS MORNING...THE MARINE LAYER REMAINS ABOUT 1500 FT DEEP AND LOW CLOUDS
ARE SLOWLY DEVELOPING AND INCREASING IN COVERAGE OVER THE COASTAL AREAS.
LOW CLOUD FORMATION COULD BE DISRUPTED BY MID-LEVEL DEBRIS CLOUDS MOVING
IN FROM THE SOUTHEAST AS MESOSCALE CONVECTIVE SYSTEMS OVER AZ AND NORTHERN
MX COLLAPSE. HOWEVER, SOCAL IS UNLIKELY TO SEE A REPEAT OF THE NOCTURNAL
CONVECTION WE SAW THURSDAY NIGHT DUE TO A LESS UNSTABLE ENVIRONMENT.
NUMERICAL MODELS ARE IN GOOD AGREEMENT THROUGH THE MIDDLE OF NEXT
WEEK WITH RESPECT TO THE LARGE-SCALE PATTERN. HIGH PRESSURE CENTERED
OVER THE INTER-MOUNTAIN WEST WILL DOMINATE OUR WEATHER THROUGH
MONDAY THEN A LOW PRESSURE TROUGH WILL DEEPEN ALONG THE WEST
COAST FOR THE MIDDLE THROUGH THE END OF NEXT WEEK.
ALTHOUGH TEMPERATURES WILL VERY SLOWLY TREND LOWER, DAYTIME HIGH
TEMPERATURES WILL REMAIN ABOUT 5-10 DEGREES ABOVE NORMAL FOR MOST
AREAS THROUGH MONDAY WHILE OVERNIGHT LOW TEMPS WILL REMAIN 5-10
DEGREES ABOVE NORMAL ONLY IN THE MOUNTAINS AND DESERTS. THE
MONSOONAL FLOW WILL PERSIST AND CONTINUE TO BRING US SIGNIFICANT
DEEP-LAYER MOISTURE. THIS WILL MAINTAIN SOME CHANCES FOR
AFTERNOON/EVENING SHOWERS/TSTMS THROUGH TUESDAY. THE MARINE LAYER
WILL REMAIN SHALLOW AND THE NIGHT AND MORNING LOW CLOUDS WILL
MOSTLY BE RESTRICTED TO THE COASTAL AREAS.
CONDITIONS BEGIN TO CHANGE MORE NOTICEABLY FOR THE MIDDLE THROUGH
THE END OF NEXT WEEK AS MODELS CONSISTENTLY SHOW A TROUGH OF LOW
PRESSURE DEEPENING ALONG THE WEST COAST AND DISPLACING THE HIGH
PRESSURE CENTER AS FAR TO THE SOUTHEAST AS THE FL PANHANDLE BY
NEXT FRIDAY. THIS WILL BRING US COOLER AND DRIER CONDITIONS WITH A
DEEPER MARINE LAYER. BY NEXT THURSDAY, DAYTIME HIGH TEMPS WILL BE
NEAR NORMAL ALONG THE COAST AND 5-10 DEGREES BELOW NORMAL FOR
INLAND AREAS. THE BELOW-NORMAL TEMPS WILL LIKELY CONTINUE INTO
NEXT WEEKEND. THE TROUGH WILL BRING DRY SOUTHWEST FLOW ALOFT,
ENDING THE CHANCES FOR PM SHOWERS/TSTMS BY WED. LOW CLOUDS AND FOG
COULD SPREAD INLAND TO COVER MOST OF THE AREA WEST OF THE
MOUNTAINS BY THURSDAY NIGHT.
AVIATION
080530Z....COAST...PATCHY LOW CLOUDS BASED 1000-1400 FT MSL HAVE
STARTED TO DEVELOP OVER COASTAL AREAS LATE THIS EVENING. CLOUDS WILL
SLOWLY INCREASE IN COVERAGE OVERNIGHT, WITH INTERMITTENT CIGS AT
COASTAL TAF SITES. BEST CHANCE FOR CIGS WILL BE 11-15Z SAT. ANY LOW
CLOUDS THAT DEVELOP WILL SCATTER BACK TO THE COASTLINE BY 16-17Z.
SKC AND VFR THROUGH SATURDAY AFTERNOON AND EVENING.
VALLEYS/MOUNTAINS/DESERTS
MOSTLY CLEAR ACROSS THE REGION THROUGH
SATURDAY, EXCEPT FOR SCT CUMULUS AT 10000 FEET MSL OVER MOUNTAINS
AFTER 20Z WITH AN ISOLATED TSRA AROUND KL35.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH WEDNESDAY.
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.
HEAT ADVISORY FROM 10 AM THIS MORNING TO 8 PM PDT SUNDAY FOR
ORANGE COUNTY INLAND AREAS-SAN DIEGO COUNTY VALLEYS-SANTA
ANA MOUNTAINS AND FOOTHILLS.
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...PG
AVIATION/MARINE...KW
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