753
FXUS66 KSGX 250533
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
1033 PM PDT WED JUN 24 2026
SYNOPSIS
A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO
THIS MORNING, MAINLY FOR THE MOUNTAINS AND DESERTS OF SAN
BERNARDINO COUNTY. A LOW PRESSURE SYSTEM TO THE NORTH WILL BRING
STRONGER ONSHORE FLOW AND A COOLING TREND FOR THURSDAY THROUGH
THE WEEKEND WITH SUNDAY HIGH TEMPERATURES NEAR THE COOLEST FOR THE
DATE FOR A FEW LOCATIONS. SOUTHWEST TO WEST WINDS FOR THE
MOUNTAINS AND DESERTS DURING THE AFTERNOON AND EVENING WILL
STRENGTHEN FOR THURSDAY THROUGH SATURDAY, THEN WEAKEN FOR EARLY
NEXT WEEK. THE MARINE LAYER WILL DEEPEN LATE IN THE WEEK INTO THE
WEEKEND WITH NIGHT AND MORNING COASTAL LOW CLOUDS EXTENDING WELL
INLAND AND ONTO THE COASTAL SLOPES OF THE MOUNTAINS FOR EARLY
SATURDAY. THEN WARMER FOR EARLY NEXT WEEK, BUT WITH HIGH
TEMPERATURES REMAINING BELOW AVERAGE.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
UPDATED AVIATION DISCUSSION FOR 06Z TAF PACKAGE
CURRENT SATELLITE THIS AFTERNOON SHOWS A NOTABLE DECREASE IN MID
LEVEL CLOUD COVERAGE FROM SOUTHWEST TO NORTHEAST AS THE SHORTWAVE
TROUGH THAT PROVIDED A BOLSTER OF MOISTURE AND SYNOPTIC LIFT HAS
PROGRESSED INTO THE GREAT BASIN. WITH THIS, WE EXPECT AN END TO THE
ELEVATED SHOWER CHANCES FOR THE SAN BERNARDINO MOUNTAINS AND HIGH
DESERT BY MID-LATE THIS AFTERNOON. MEANWHILE, STRONG UPPER LEVEL
HIGH PRESSURE IN CONTROL ACROSS THE DESERT SOUTHWEST HAS A RIDGE
AXIS STRETCHING WESTWARD OVER SOUTHERN CALIFORNIA. THIS AND THE
ADDED MOISTURE FROM THE MONSOONAL DISTURBANCE ALOFT IS YIELDING MILD
AFTERNOON HIGH AND OVERNIGHT LOW TEMPERATURES, WITH SOME MINOR
HEATRISK FOR THE INLAND VALLEYS, WITH MODERATE HEATRISK IN THE
DESERTS. PORTIONS OF THE LOWER DESERTS OF SAN DIEGO VALLEY ARE
SEEING LOCALLY MAJOR HEATRISK WITH THE HIGHEST COMBINATION OF
TEMPERATURE AND HUMIDITY, WHERE AN EXTREME HEAT WARNING REMAINS IN
EFFECT THROUGH 8 PM THURSDAY. THURSDAY WILL MARK THE BEGINNING OF A
LATE WEEK COOLING TEND, BUT WITH ANOTHER MILD NIGHT BEFORE THE MID
LEVEL MOISTURE AND INCREASE HUMIDITY FULLY DEPART, SO THERE IS STILL
MODERATE HEATRISK IN THE DESERTS INTO THE AFTERNOON.
ALL ATTENTION QUICKLY TURNS TO A HIGHLY UNSEASONABLE TROUGH THAT IS
SET TO PUSH INTO THE PACIFIC NORTHWEST ON THURSDAY/FRIDAY. THIS
TROUGH WILL KICK OUT THE MONSOONAL MOISTURE FOR GOOD, SHOVE THE
RIDGE SOUTH AND EAST, AND BRING MUCH COOLER AIR TO THE REGION FOR
THE WEEKEND AND INTO NEXT WEEK. ENSEMBLES AND CLUSTERS PROVIDE GOOD
CONFIDENCE IN THE STRENGTH AND PROGRESSION OF THIS LARGE AND
ANOMALOUS TROUGH, SET TO DIVE DOWN INTO CALIFORNIA AND DOMINATE
ACROSS THE WEST FOR THE WEEKEND. TEMPERATURES QUICKLY FALL BELOW
NORMAL AREA WIDE BY FRIDAY, WITH AFTERNOON HIGH TEMPERATURES LIKELY
TO FALL 15 TO EVEN 20 DEGREES BELOW NORMAL FOR SATURDAY AND SUNDAY.
THE CURRENTLY FORECAST TEMPERATURES ARE SO UNSEASONABLY LOW THAT
RECORD COOL HIGH TEMPERATURE FORECASTS COULD BE CHALLENGED THIS
WEEKEND. IN ADDITION TO THE COOL TEMPERATURES, THIS TROUGH WILL
BRING A STRENGTHENING TREND FOR THE ONSHORE WINDS, ESPECIALLY FOR
THE DESERT MOUNTAIN SLOPES AND DESERTS. WIND GUSTS ON FRIDAY
AFTERNOON COULD BE NEAR ADVISORY-LEVEL CRITERIA WITH 35-40 MPH FOR
THE DESERTS, AND LOCALLY 45-60+ MPH IN MOUNTAIN PASSES. THE
STRONGEST WINDS LOOK TO PEAK SATURDAY AFTERNOON, AND THEN WEAKENING
INTO SUNDAY. DRY CONDITIONS IN THE HIGH DESERTS WILL LIKELY BRING
ELEVATED FIRE CONCERNS, SO SEE THE FIRE WEATHER SECTION BELOW FOR
MORE DETAILS.
LOOKING AHEAD INTO NEXT WEEK, ENSEMBLES INDICATE THE LARGE COULD
COULD GET A FEW REINFORCING SHORTWAVES THAT COULD EXTEND ITS
PRESENCE ACROSS THE WESTERN US WELL INTO MIDDLE PART OF NEXT WEEK.
NBM CURRENTLY FAVORS BELOW NORMAL TEMPERATURES LINGERING ACROSS
SOCAL THROUGH AT LEAST WEDNESDAY.
AVIATION
250530Z...COAST/VALLEYS...MUCH MORE UNIFORM COVERAGE THIS EVENING
WITH LOW CLOUDS ALREADY OVER COASTAL AREAS AND PUSHING INTO ADJACENT
VALLEYS. CIGS ARE CURRENTLY 1200-1700FT MSL AND SHOULD STAY IN THAT
GENERAL AREA THROUGH THE NIGHT AND INTO THE MORNING. MINOR VIS
RESTRICTIONS OF 2-5SM WILL BE POSSIBLE WHERE CLOUDS INTERSECT
TERRAIN. LOW CLOUDS OVER INLAND AREAS WILL BEGIN TO CLEAR 15-17Z AND
COASTAL AREAS 16-18Z. LOW CLOUDS MAY LINGER OVER COASTAL SAN DIEGO
THROUGH 20Z. SIMILAR CIGS ARE EXPECTED TO RETURN AFTER 01-03Z FRIDAY.
MOUNTAINS/DESERTS...VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD.
WEST-SOUTHWEST WINDS BECOME ELEVATED ALONG DESERT SLOPES AND LOCALLY
INTO DESERTS AFTER 21Z. EXPECT GUSTS OF 25-35 KTS WITH GUSTS UP TO
45 KTS THROUGH THE BANNING PASS AND INTO THE NORTHERN COACHELLA
VALLEY. MOD UP/DOWNDRAFTS IN LEE OF MTNS.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH TUESDAY.
BEACHES
A LONG-PERIOD SOUTH SWELL WILL CONTINUE TO BRING SURF OF 3 TO 6 FEET
THROUGH THURSDAY WITH THE HIGHEST SURF ON SOUTH FACING BEACHES. SEE
THE BEACH HAZARDS STATEMENT FOR DETAILS.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...BEACH HAZARDS STATEMENT THROUGH THURSDAY EVENING FOR ORANGE
COUNTY COASTAL AREAS-SAN DIEGO COUNTY COASTAL AREAS.
EXTREME HEAT WARNING UNTIL 8 PM PDT THURSDAY FOR SAN DIEGO
COUNTY DESERTS.
PZ...NONE.
PUBLIC...MUNYAN
AVIATION/MARINE/BEACHES...VILLAFANE
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