411
FXUS66 KSGX 020912
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
212 AM PDT SAT AUG 2 2025
SYNOPSIS
TEMPERATURES NEAR AVERAGE AND MARINE LAYER LOW CLOUDS EACH NIGHT
AND MORNING ALONG THE COAST AND IN THE WESTERN VALLEYS THROUGH
TUESDAY. HIGH PRESSURE OVER THE DESERT SOUTHWEST WILL STRENGTHEN
THE LATTER HALF OF NEXT WEEK, BRINGING A WARMING TREND WITH
TEMPERATURES 5 TO 10 DEGREES ABOVE AVERAGE AWAY FROM THE COAST.
THERE IS THE POTENTIAL FOR MONSOON MOISTURE TO RETURN LATE IN THE
WEEK BUT PRECIPITATION CHANCES REMAIN BELOW 10 PERCENT.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
MARINE LAYER LOW CLOUDS HAVE FILLED IN ALONG THE COAST AND SPREAD
INTO THE WESTERN VALLEYS AGAIN THIS MORNING. ELSEWHERE SKIES
REMAIN CLEAR. LOW CLOUDS WILL CLEAR BY LATE MORNING.
AN UPPER LEVEL HIGH CENTERED NEAR SOUTHERN ARIZONA WILL SHIFT
WESTWARD TOWARDS CALIFORNIA TODAY, BRINGING A COUPLE MORE DEGREES
OF WARMING FOR INLAND AREAS WHILE COASTAL AREAS REMAIN MODERATED
BY THE MARINE LAYER. IN GENERAL HIGHS WILL BE NEAR NORMAL FOR MOST
AREAS, AND AROUND 3-5 DEGREES ABOVE NORMAL IN THE DESERTS. THIS
HIGH STAYS IN PLACE SUNDAY, THEN SLOWLY WEAKENS AND SHIFTS BACK
EASTWARDS MONDAY AND TUESDAY AS AN UPPER LEVEL TROUGH MOVES BY TO
THE NORTH. OVERALL ONLY MINOR TEMPERATURE FLUCTUATIONS ARE
EXPECTED FOR THE EARLY PART OF THE WEEK WITH NIGHT AND MORNING LOW
CLOUDS CONTINUING FOR THE COASTAL AREAS AND FAR WESTERN VALLEYS.
ENSEMBLES ARE IN VERY GOOD AGREEMENT WITH THE UPPER LEVEL HIGH
STRENGTHENING OVER AZ/NM DURING THE SECOND HALF THE WEEK. THIS
WILL BRING MORE WARMING INLAND, WITH THE PEAK OF THE HEAT LIKELY
OCCURRING THURSDAY WITH MINOR COOLING FRIDAY. ABOUT 30% OF THE
ENSEMBLE SPACE KEEPS WARMER WEATHER INTO SATURDAY WHILE THE
REMAINING MEMBERS ARE COOLER WITH THE UPPER HIGH WEAKENING. FOR
THURSDAY, HIGHS WILL BE AROUND 5-10 DEGREES ABOVE NORMAL INLAND
AND AROUND 3-5 DEGREES ABOVE NORMAL NEAR THE COAST. THERE IS A
70-90% CHANCE OF HIGH TEMPERATURES OF 100 OR MORE IN THE INTERIOR
PORTIONS OF THE INLAND EMPIRE AND A 70-100% CHANCE FOR LOWER
ELEVATIONS OF THE UPPER DESERT. THERE IS A 60-90% CHANCE OF HIGH
TEMPERATURES OF 115 OR MORE ACROSS THE LOW DESERTS, BUT A LESS
THAN 10% CHANCE OF TEMPERATURES OF 120 OR MORE. WIDESPREAD HIGH
HEATRISK IS FORECAST ACROSS THE LOWER DESERTS AND MODERATE
HEATRISK FOR THE MOUNTAINS AND VALLEYS ON THURSDAY, WITH
DECREASING COVERAGE ON FRIDAY.
ALL GLOBAL ENSEMBLES HAVE A MODEST INCREASE IN PRECIPITABLE WATER
BEGINNING TUESDAY OR WEDNESDAY WITH A CONTINUED SLOW INCREASE
THROUGH THE END OF THE WEEK WITH ENSEMBLE MEANS NEAR 1-1.25". WITH
THE EAST-WEST RIDGE AXIS ALMOST DIRECTLY OVERHEAD WE WILL STILL
LACK THE INSTABILITY FOR SHOWERS/THUNDERSTORMS, SO FORECAST
REMAINS DRY. LOW LEVEL MOISTURE INTRUSIONS FROM THE GULF OF
CALIFORNIA ARE STILL A POSSIBILITY FOR LATE IN THE WEEK, WHICH
WOULD RESULT IN SLIGHTLY LOWER AIR TEMPERATURES DURING THE DAY BUT
MORE HUMIDITY/HIGHER HEAT INDICES.
AVIATION
020830Z....COASTS/WESTERN VALLEYS...LOW CLOUDS BASED 700-1200FT MSL
HAVE SUCCESSFULLY MOVED INLAND WITH VERY LIMITED FILTERING INTO THE
INLAND EMPIRE. BASES WILL LOWER CLOSER TO 700-900FT MSL THROUGH 13Z.
VIS DOWN TO 1-5SM PRIMARILY FOR COASTAL TERRAIN AND VALLEYS. CLOUDS
CLEAR TO THE BEACHES BY 17Z, REDEVELOPING AGAIN TONIGHT AND MOVING
INLAND AFTER 05Z SUNDAY. BASES TONIGHT WILL BE SIMILAR TO THIS
MORNING, AROUND 700-900FT MSL.
INLAND VALLEYS/MOUNTAINS/DESERTS
MOSTLY CLEAR WITH VFR CONDITIONS
THROUGH SUNDAY MORNING.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH THURSDAY.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...NONE.
PUBLIC...SS
AVIATION/MARINE...ZUBER
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