878
FXUS66 KSGX 190944
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
244 AM PDT THU JUN 19 2025
SYNOPSIS
LOW PRESSURE MOVING INLAND INTO THE WESTERN STATES WILL BRING
COOLING THROUGH SATURDAY WITH SATURDAY HIGH TEMPERATURES AS MUCH
AS 8 TO 12 DEGREES BELOW AVERAGE FOR THE MOUNTAINS, INLAND
VALLEYS, AND HIGH DESERT. THERE WILL GUSTY SOUTHWEST TO WEST WINDS
DURING THE AFTERNOONS AND EVENINGS FOR THE MOUNTAINS AND DESERTS
WITH THE STRONGER GUSTS TO 35 TO 45 MPH. THE MARINE LAYER WILL
DEEPEN WITH NIGHT AND MORNING COASTAL LOW CLOUDS SPREADING FARTHER
INLAND TO THE VALLEYS. FOR SUNDAY THROUGH WEDNESDAY, LOW PRESSURE
WILL WEAKEN SOME, BUT REMAIN ACROSS THE AREA. HIGH TEMPERATURES
WILL WARM 5 TO LOCALLY 10 DEGREES BUT REMAIN BELOW AVERAGE BY
AROUND 5 DEGREES.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
SHORT TERM (TODAY THROUGH SATURDAY)
THE MARINE LAYER HAS DEEPENED TO AROUND 2000 FEET WITH SATELLITE
IMAGERY SHOWING COASTAL LOW CLOUDS COVERING ALL OF THE ORANGE
COUNTY COASTAL PLAIN AND THE WESTERN HALF OF THE SAN DIEGO COUNTY
VALLEYS. THROUGH SUNRISE, THE LOW CLOUDS MAY BEGIN TO SPREAD INTO
FAR SOUTHERN AND FAR WESTERN PORTIONS OF THE INLAND EMPIRE.
WEDNESDAY HIGH TEMPERATURES WERE A FEW DEGREES COOLER THAN TUESDAY
FOR THE COAST AND VALLEYS. A LOW PRESSURE SYSTEM MOVING INLAND
INTO THE WESTERN STATES WILL SPREAD COOLING INLAND THROUGH
SATURDAY. SATURDAY HIGH TEMPERATURES WILL BE AS MUCH AS 8 TO 12
DEGREES BELOW AVERAGE FOR THE MOUNTAINS, INLAND VALLEYS, AND HIGH
DESERT WITH HIGH TEMPERATURES RANGING FROM AROUND 70 NEAR THE
COAST TO THE MID 70S TO LOWER 80S FOR THE INLAND EMPIRE WITH
AROUND 100 FOR THE LOWER DESERTS.
THE MARINE LAYER WILL DEEPEN TO AROUND 2500 FEET FOR SATURDAY WITH
NIGHT AND MORNING COASTAL LOW CLOUDS SPREADING FARTHER INTO
THE VALLEYS. STRONGER ONSHORE FLOW WILL ALSO BRING STRONGER AND
GUSTY SOUTHWEST TO WEST WINDS FOR THE DESERTS ONTO THE DESERT
SLOPES OF THE MOUNTAINS WITH THE STRONGER GUSTS DURING THE
AFTERNOONS AND EVENINGS TO 35 TO 45 MPH.
LONG TERM (SUNDAY THROUGH WEDNESDAY)
LOW PRESSURE WILL WEAKEN SOME, BUT REMAIN ACROSS THE AREA. HIGH
TEMPERATURES WILL WARM 5 TO LOCALLY 10 DEGREES BUT REMAIN BELOW
AVERAGE BY AROUND 5 DEGREES. THE MARINE LAYER WILL DECREASE IN
DEPTH TO AROUND 1500 TO 2000 FEET WITH NIGHT AND MORNING COASTAL
LOW CLOUDS SPREADING INLAND INTO THE WESTERN VALLEYS.
AVIATION
190930Z....COAST/VALLEYS...LOW CLOUDS HAVE FILLED IN QUITE UNIFORMLY
ACROSS THE COASTS AND UP TO 15-20 MILES INLAND. BASES ARE SITTING
AROUND 1000-1300FT MSL WITH TOPS TO ABOUT 1700-1900FT MSL, THOUGH
BASES MAY FALL SOME BY 12-14Z. CLOSER TO 800-1100FT MSL. THESE
CLOUDS COULD FILTER INTO THE SOUTHERN AND WESTERN INLAND EMPIRE,
WITH A 35-40% CHANCE OF CIGS AT KONT ANYTIME BETWEEN 11Z-16Z. VIS
RESTRICTIONS LIMITED TO WHERE TERRAIN INTERSECTS THE CLOUD LAYER AND
WITHIN INLAND VALLEYS. CLOUDS CLEARING TO THE COASTS BY 17-19Z. LOW
CLOUDS DEVELOP AGAIN TONIGHT AND PUSH BACK INLAND AFTER 01Z FRIDAY
WITH SLIGHTLY HIGHER BASES CLOSER TO 1500FT MORE INLAND EXTENT.
MOUNTAINS/DESERTS...CLEAR SKIES AND UNRESTRICTED VIS THROUGH
EARLY FRIDAY MORNING.
MARINE
NORTHWEST WINDS MAY GUST CLOSE TO 20 KNOTS NEAR SAN CLEMENTE ISLAND
FRIDAY AFTERNOON AND EVENING. OTHERWISE, NO HAZARDOUS MARINE
CONDITIONS ARE EXPECTED THROUGH SUNDAY.
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...17
AVIATION/MARINE...MUNYAN
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