894
FXUS66 KSGX 052333
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
433 PM PDT MON OCT 5 2026
SYNOPSIS
HIGH PRESSURE REMAINS OVER THE REGION, BRINGING A PROLONGED PERIOD
OF HOT WEATHER, MOST NOTABLE WEST OF THE MOUNTAINS. ELEVATED FIRE
WEATHER RISK CONTINUES THROUGH TODAY WITH LIGHT SANTA ANA WINDS
EASING THROUGHOUT THE DAY. AN AREA OF LOW PRESSURE WILL MOVE OVER
THE WESTERN PART OF THE COUNTRY BY THE END OF THE WEEK. THIS WILL
BRING COOLER WEATHER AND A DEEPER MARINE LAYER TO OUR REGION, WITH
LOW CONFIDENCE ON THE WEATHER SYSTEM GIVING US ANY WET WEATHER.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
..UPDATED AVIATION DISCUSSION
ANOTHER HOT DAY IS IN STORE AS HIGH PRESSURE REMAINS OVER THE
SOUTHWEST. VALLEY AND COASTAL LOCATIONS SOARING INTO THE 90S AGAIN
THIS MORNING AS WEAK OFFSHORE WINDS HOLD ACROSS THE AREA. MODELS
SHOW BETTER ONSHORE FLOW (WEST WINDS) CLOSER TO THE COAST AND FAR
WESTERN VALLEYS OVER THE NEXT COUPLE OF DAYS. STILL THINKING
TEMPERATURES FROM TODAY INTO TUESDAY WILL BE RELATIVELY SIMILAR. A
SUBTLE INCREASE IN TEMPERATURES WILL BE SEEN AT THE COAST AS A
THERMAL RIDGE EXPANDS NORTHWARD WEDNESDAY INTO THURSDAY. THIS WILL
MAINLY BE FELT ACROSS THE MOUNTAINS AND THE DESERTS WITH HIGHS
INCREASING 3-5 DEGREES FROM WHERE THEY ARE TODAY. LOW TEMPERATURES
WILL STILL REMAIN WARM OVER THE REGION WITH MANY PLACES STAYING INTO
THE 70S OVERNIGHT IN THE LOWER DESERTS AND WEST OF THE MOUNTAINS.
LIGHT OFFSHORE FLOW AT NIGHT WILL BE THE MAIN DRIVER OF LOW
TEMPERATURES. WIND-SHELTERED VALLEYS WILL LOWER INTO THE 60S IN SOME
AREAS, WHILE COMMUNITIES THAT SEE WIND THE WHOLE NIGHT WILL STAY IN
THE MID 70S TO NEAR 80. PLEASE CONTINUE TO PRACTICE HEAT SAFETY BY
FINDING PLACES WITH A/C AND CHECKING ON FRIENDS AND FAMILY. THE
MARINE LAYER WILL ALSO SUBTLY BUILD ON WEDNESDAY INTO THURSDAY, BUT
CONFIDENCE IS LOWER ON WHEN LOW CLOUDS AND FOG REACH COASTAL AREAS.
FORECAST NOW SHOWS FOG POSSIBLY MOVING ALONG THE COAST BY WEDNESDAY
MORNING. CHANCES FOR LOW CLOUDS AND FOG WILL INCREASE THURSDAY INTO
FRIDAY, AND MOST DEFINITELY BY THE WEEKEND FOR MUCH OF THE COASTAL
BASIN.
MODELS ARE STARTING TO COME INTO BETTER AGREEMENT ON WHEN A TROUGH
OF LOW PRESSURE ENTERS THE PACIFIC NORTHWEST, SOMETIME LATER ON
FRIDAY INTO EARLY SATURDAY. THIS SYSTEM WILL HELP WEAKEN THE HIGH
PRESSURE SYSTEM OVER AREA. HEIGHT FALLS WILL LEAD TO GREATER ONSHORE
FLOW AND COOLING. HIGHS FROM THURSDAY TO FRIDAY WILL DROP ANOTHER 1-
4 DEGREES, WITH THE GREATER COOLING OCCURRING FROM FRIDAY TO
SATURDAY WITH HIGHS LOWERING ANOTHER 5-10 DEGREES. FRIDAY WILL SEE
HIGHS CLOSER TO 100 DEGREES FOR THE LOWER DESERTS AND INLAND COASTAL
VALLEYS, WITH 80S MORE COMMON NEAR THE COAST. MODELS START TO
DIVERGE ONCE AGAIN ON WHERE THIS TROUGH WILL GO AND HOW FAR SOUTH IT
PLUNGES ACROSS THE WESTERN U.S. FOR NOW, ANOTHER SIGNIFICANT
TEMPERATURE DROP IS IN THE FORECAST FROM SATURDAY TO SUNDAY WITH
HIGHS LOWERING ANOTHER 5-10 DEGREES. ON SUNDAY, THERE'S AROUND A 50-
50 CHANCE OF TEMPERATURES STAYING BELOW 80 DEGREES FOR THE VALLEYS
WEST OF THE MOUNTAINS AS WELL AS THE LARGE CITIES OF THE HIGH
DESERT.
THE PATH OF THE WEATHER SYSTEM WILL DETERMINE HOW COOL WE BECOME AND
IF WE ARE ABLE TO SEE ANY PRECIPITATION ALONG AND WEST OF THE
MOUNTAINS. GLOBAL MODELS CONTINUE TO SHOW LARGE DISCREPANCIES ON HOW
THIS FEATURE EVOLVES. TAKING A LOOK AT MODEL ENSEMBLES, ECMWF BRINGS
A WETTER PATTERN WITH ABOUT 3/4 OF THE GUIDANCE SHOWING LIGHT
PRECIPITATION WHILE THE GFS ENSEMBLES SHOW A DRY PATTERN WITH ABOUT
1/4 OF ENSEMBLES SHOWING LIGHT PRECIPITATION SUNDAY THROUGH POSSIBLY
NEXT TUESDAY. LOW CONFIDENCE REMAINS ON ANY PRECIPITATION ACROSS THE
REGION, BUT CONFIDENCE IS MUCH HIGHER IN SEEING COOLER AND BREEZIER
WEATHER, ALONG WITH LOW CLOUDS EACH MORNING WEST OF THE MOUNTAINS.
AVIATION
052330Z...SKC AND VFR THROUGH TUESDAY EVENING.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH FRIDAY.
BEACHES
INCREASING SOUTH-SOUTHWEST SWELL WILL CREATE ELEVATED SURF OF 3-6
FEET, WITH SETS TO 7 FEET ALONG SOUTH AND SOUTHWEST FACING BEACHES
STARTING LATE TUESDAY. STRONG RIP CURRENTS EXPECTED. ADDITIONALLY,
THIS WILL COINCIDE WITH HIGH TIDES DURING THE MORNINGS AND EVENINGS
TO CREATE MINOR COASTAL FLOODING AND BEACH EROSION. A BEACH HAZARDS
STATEMENT AND A COASTAL FLOOD ADVISORY HAVE BEEN ISSUED WITH MORE
DETAILS.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...EXTREME HEAT WARNING UNTIL 8 PM PDT THURSDAY FOR ORANGE COUNTY
COASTAL AREAS-ORANGE COUNTY INLAND AREAS-SAN BERNARDINO AND
RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE-SAN DIEGO COUNTY
COASTAL AREAS-SAN DIEGO COUNTY VALLEYS-SANTA ANA MOUNTAINS
AND FOOTHILLS.
BEACH HAZARDS STATEMENT FROM TUESDAY AFTERNOON THROUGH FRIDAY
EVENING FOR ORANGE COUNTY COASTAL AREAS-SAN DIEGO COUNTY
COASTAL AREAS.
COASTAL FLOOD ADVISORY FROM 6 AM WEDNESDAY TO 11 AM PDT FRIDAY
FOR ORANGE COUNTY COASTAL AREAS-SAN DIEGO COUNTY COASTAL
AREAS.
PZ...NONE.
PUBLIC...APR
AVIATION/MARINE/BEACHES...KW
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