120
FXUS66 KSGX 151021
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
321 AM PDT THU OCT 15 2026
SYNOPSIS
SANTA ANA WINDS EXPECTED TODAY THROUGH SATURDAY, WITH THE
STRONGEST AND MOST WIDESPREAD ON FRIDAY. ADDITIONALLY, MODERATE TO
MAJOR HEATRISK IS EXPECTED FOR COASTAL AREAS. COOLER CONDITIONS
WILL SPREAD INLAND SUNDAY, WITH GREATER COOLING AND CHANCE OF
SHOWERS NEXT TUESDAY AND WEDNESDAY.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
TODAY THROUGH TOMORROW NIGHT...
AS AN UPPER LEVEL LOW THAT HAS BEEN CUT OFF EAST OF THE REGION
ESTABLISHES ITSELF TO THE SOUTHWEST OF SAN DIEGO, WITH A HIGH
POSITIONED TO THE NORTH OVER NORTHWESTERN NEVADA IN A REX BLOCKING
PATTERN, THE PRESSURE GRADIENT BETWEEN THE TWO ARE GOING TO ALLOW
FOR OFFSHORE WINDS TO STRENGTHEN, INITALLY OUT OF THE NORTH TO
NORTHEASTERLY DIRECTION TODAY, AND THEN BECOMING MORE EASTERLY
TOMORROW. THESE WINDS ARE EXPECTED TO PEAK TOMORROW, WITH GUSTS AT
AROUND 35 TO 55 MPH FOR THE INLAND VALLEYS, AND STRONGER GUSTS ALONG
THE SLOPES, WITH LOCAL GUSTS APPROACHING 70 MPH WITHIN SOME OF THE
HIGHER TERRAIN PASSES AND CANYONS. AS THE LOW TAPS INTO SOME OF THE
REMNANT TROPICAL MOISTURE FROM SIMON, IT WILL PROVIDE A SLIGHT
INCREASE IN HUMIDITY TOMORROW, AND THERE WILL BE SLIGHT CHANCE OF A
SHOWER OR TWO DEVELOPING OVER THE MOUNTAINS DURING THE AFTERNOON
HOURS. RH VALUES WILL DIMINISH TO 15-25 PERCENT BY LATER THIS
AFTEROON, BUT THEN GRADUALLY INCREASE TO 20 TO 30 PERCENT MINIMUM
VALUES FROM FRIDAY, WITH THE INFLUX OF MOISTURE. (SEE FIRE WEATHER
SECTION BELOW). TEMPERATURES WILL BE WARMEST FOR THE COASTAL
LOCATIONS, DUE TO THE OFFSHORE FLOW. THIS WILL ALSO HELP TO IMPEDE
THE MARINE LAYER FROM FORMING OVERNIGHT. HIGHS WILL BE THE WARMEST
TOMORROW, AND FORE THE COASTAL REGIONS, RANGING FROM UPPER 80S TO
LOW 90S, HENCE THE REASON FOR THE HEAT ADVISORY.
THIS WEEKEND THROUGH NEXT WEDNESDAY...
SANTA ANA CONDITIONS WILL PERSIST THROUGH SATURDAY, AND THEN THESE
OFFSHORE WINDS WILL BEGIN TO WEAKEN. TEMPERATURES WILL GRADUALLY
COOL THROUGHOUT THE WEEKEND, AND ONSHORE FLOW WILL EVENTUALLY
RETURN GOING INTO SUNDAY, WHCIH MAY BRING ABOUT THE ONSET OF SOME
DENSE FOG FOR PORTIONS OF THE COASTAL AREAS DURING THE EARLY
MORNING HOURS. THERE WILL ALSO BE AN APPROACHING MAJOR SHORTWAVE
TROUGH TOWARDS THE MIDDLE PART OF NEXT WEEK, WHICH WILL BRING
CHANCES OF PRECIPITATION BACK INTO THE PICTURE BY LATE TUESDAY
INTO WEDNESDAY, ALONG WITH THE RETURN OF MUCH COOLER TEMPERATURES.
AVIATION
150530Z...SKC AND VFR THROUGH THURSDAY. AREAS OF NORTHEAST WINDS
GUSTING 15-20 KTS IN THE MOUNTAIN FOOTHILLS INCREASING AFTER 10Z
WITH GUSTS 20-45 KTS, EXPANDING IN COVERAGE AND SPREADING INTO
INLAND VALLEYS AFTER 13Z. AREAS OF MOD-STG UP/DOWNDRAFTS IN LEE OF
(SOUTH AND WEST OF) MOUNTAINS ALONG WITH AREAS OF LLWS WHERE STRONG
WINDS DO NOT SURFACE IN VALLEYS.
MARINE
ISOLATED NORTHEAST GUSTS COULD EXCEED 20 KNOTS FRIDAY INTO EARLY
SATURDAY. OTHERWISE, NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED
THROUGH SUNDAY.
BEACHES
A PREVAILING SOUTHERLY SWELL WILL CONTINUE MOST OF THIS WEEK,
GENERATING SURF 3-6 FEET WITH LOCAL SETS TO 7 FEET, ALONG WITH
STRONG RIP CURRENTS. LATE MORNING HIGH TIDES NEAR 6.5 FEET WILL
CONTINUE THROUGH THURSDAY, PRODUCING MINOR COASTAL FLOODING. TIDES
ARE EXPECTED FALL BELOW 6.5 FT MLLW AFTER THE THURSDAY MORNING HIGH
TIDE, DIMINISHING THE THREAT FOR COASTAL FLOODING.
FIRE WEATHER
ELEVATED FIRE WEATHER CONDITIONS WITH NEAR CRITICAL CONDITIONS IN
LOCATIONS WITH ABUNDANT DRY FUELS WHERE TOPOGRAPHY AND WIND
DIRECTION ARE WELL ALIGNED FOR TODAY THROUGH SATURDAY.
NORTHEAST TO EAST WITH SANTA ANA WINDS ARE EXPECTED TO INCREASE
LATER TODAY AND CONTINUE THROUGH SATURDAY, WITH THE STRONGEST AND
MOST WIDESPREAD WINDS ON FRIDAY. WINDS WILL BE MOSTLY OUT OF THE
NORTH AND NORTHEAST THURSDAY, BECOMING MORE NORTHEAST TO EAST BY
FRIDAY, AND EASTERLY ON SATURDAY. GUSTS FOR THE VALLEYS WILL
MAINLY BE 35 TO 55 MPH, WITH THE STRONGEST WINDS BELOW PASSES AND
NEAR MOUNTAIN FOOTHILLS. FOR THE COASTAL SLOPES AND THROUGH
PASSES, LOCAL GUSTS HAVE THE POTENTIAL TO EXCEED 65 MPH. LOWEST
DAYTIME RELATIVE HUMIDITY FOR THE VALLEYS AND INLAND COASTAL AREAS
WILL FALL TO 15 TO 25 PERCENT BY LATER THIS AFTERNOON, THEN
RECOVER TO 20 TO 30 PERCENT FOR FRIDAY AND SATURDAY. WINDS WILL
WEAKEN FROM FRIDAY'S PEAK ON SATURDAY BUT REMAIN ELEVATED. MUCH
WEAKER OFFSHORE WINDS EXPECTED SUNDAY, WITH THE PRESSURE GRADIENT
RETURNING TO ONSHORE BY MONDAY. THERE WILL BE A SLIGHT CHANCE OF A
SHOWER OR TWO DEVELOPING OVER THE MOUNTAINS AND ADJACENT DESERTS
DURING THE AFTERNOON ON FRIDAY, ALTHOUGH VERY LITTLE PROBABILITY
OF THERE BEING ANY SIGNIFICANT WETTING RAIN.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...BEACH HAZARDS STATEMENT UNTIL 2 PM PDT THIS AFTERNOON FOR ORANGE
COUNTY COASTAL AREAS-SAN DIEGO COUNTY COASTAL AREAS.
HEAT ADVISORY FROM 10 AM THIS MORNING TO 8 PM PDT SATURDAY FOR
ORANGE COUNTY COASTAL AREAS-ORANGE COUNTY INLAND AREAS-SAN
DIEGO COUNTY COASTAL AREAS.
HIGH WIND WARNING FROM 6 AM THIS MORNING TO 8 PM PDT SATURDAY
FOR SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE INLAND
EMPIRE.
HIGH WIND WARNING FROM 8 PM THIS EVENING TO 8 PM PDT SATURDAY
FOR SAN DIEGO COUNTY VALLEYS.
HIGH WIND WARNING FROM 6 AM THIS MORNING TO 8 PM PDT FRIDAY FOR
SAN BERNARDINO COUNTY MOUNTAINS.
HIGH WIND WARNING FROM 6 AM THIS MORNING TO MIDNIGHT PDT
SATURDAY NIGHT FOR RIVERSIDE COUNTY MOUNTAINS-SAN DIEGO
COUNTY MOUNTAINS-SAN GORGONIO PASS NEAR BANNING.
HIGH WIND WARNING FROM 6 AM THIS MORNING TO NOON PDT SATURDAY
FOR SANTA ANA MOUNTAINS AND FOOTHILLS.
WIND ADVISORY FROM 6 AM THIS MORNING TO NOON PDT SATURDAY FOR
ORANGE COUNTY INLAND AREAS.
PZ...NONE.
PUBLIC/FIRE WEATHER...STEWEY
AVIATION/MARINE...MM
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