558
FXUS66 KSGX 280418
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
918 PM PDT SUN JUL 27 2025
SYNOPSIS
A WARMING TREND WILL CONTINUE WITH HIGH TEMPERATURES SLIGHTLY
ABOVE NORMAL BY THE MIDDLE OF NEXT WEEK. THURSDAY AND FRIDAY WILL
BE A FEW DEGREES COOLER, WITH MINOR WARMING OVER THE UPCOMING
WEEKEND. LOW CLOUDS AND FOG WILL REACH INTO PORTIONS OF THE
VALLEYS EACH NIGHT AND MORNING.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
LOW CLOUDS HAVE MOVED BACK INTO THE COASTAL AREAS OF SAN DIEGO
COUNTY THIS EVENING AFTER CLEARING NICELY THIS AFTERNOON. CLOUDS
WILL SPREAD NORTH INTO ORANGE COUNTY AND INTO THE WESTERN VALLEYS
OVERNIGHT. THE 00Z KNKX SOUNDING SHOWS THE MARINE INVERSION BASED
NEAR 2200 FT MSL, BUT UNLIKE PREVIOUS NIGHTS, THE MARINE LAYER IS
NOT EXPECTED TO DEEPEN AS UPPER LEVEL HIGH PRESSURE BEGINS TO
NUDGE IN FROM THE EAST. ELSEWHERE SKIES WILL REMAIN MOSTLY CLEAR.
A GRADUAL WARMING TREND WILL TAKE PLACE THROUGH MIDWEEK AS THE
UPPER LEVEL HIGH CONTINUES TO EXPAND WESTWARD INTO SO CAL. HIGH
TEMPERATURES WILL BE AROUND 5-10 DEGREES BELOW NORMAL IN THE
MOUNTAINS AND VALLEYS ON MONDAY AND NEAR NORMAL ELSEWHERE, WARMING
TO NEAR NORMAL AREA-WIDE BY WEDNESDAY. FOR TUESDAY AND WEDNESDAY,
NBM PROBABILITIES OF HIGH TEMPERATURES OF 110 OR MORE ARE AROUND
30-50 PERCENT, AND IN THE INLAND EMPIRE THE CHANCE OF 100 DEGREES
OR MORE IS AROUND 20-30 PERCENT IN THE TYPICALLY HOTTEST AREAS
BETWEEN LAKE ELSINORE AND HEMET. THE MARINE LAYER BECOMES MORE
SHALLOW THROUGH THIS PERIOD WITH NIGHT AND MORNING LOW CLOUDS AND
FOG GENERALLY CONFINED TO THE COASTAL AREAS AND FAR WESTERN
VALLEYS.
BRIEF AND VERY MINOR COOLING TAKES PLACE THURSDAY AND FRIDAY AS A
WEAK TROUGH LIFTS NORTHEAST ACROSS CENTRAL CA INTO THE GREAT
BASIN. ENSEMBLES ARE IN GENERALLY GOOD AGREEMENT WITH THE HIGH
RESTRENGTHENING AS THE TROUGH MOVES OUT FOR A MINOR WARMING TREND
INTO THE WEEKEND. UNCERTAINTY GROWS EARLY NEXT WEEK WITH THE
TIMING AND AMPLITUDE OF ANOTHER TROUGH POTENTIALLY MOVING TOWARDS
THE WEST COAST. MONSOON MOISTURE REMAINS NOWHERE TO BE FOUND OVER
THE NEXT WEEK.
AVIATION
280300Z....COASTS/VALLEYS...LOW CLOUDS BASED 1100-1700 FT MSL OVER
COASTAL WATERS ARE STARTING TO MOVE INTO COASTAL SAN DIEGO COUNTY.
CLOUDS SLOWLY PUSH 15-20 MILES INLAND OVER SAN DIEGO/ORANGE
COUNTIES BY 13Z, BUT WILL LIKELY (70% CHANCE) REMAIN OUT OF THE
INLAND EMPIRE. SCATTERING TO THE COAST AGAIN MONDAY MORNING
16-18Z. CLOUDS BASED 900-1400 FT MSL SLOWLY CREEP BACK INTO
COASTAL AREAS AFTER 03Z TUESDAY.
MOUNTAINS/DESERTS...MOSTLY CLEAR WITH VFR CONDITIONS THROUGH MONDAY
EVENING.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH FRIDAY.
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...KW
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