214
FXUS66 KSGX 171907
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
1207 PM PDT SAT OCT 17 2026
SYNOPSIS
WARM CONDITIONS WITH WEAK TO LOCALLY MODERATE SANTA ANA WINDS
TODAY. COOLER CONDITIONS EXPECTED SUNDAY THROUGH THE UPCOMING
WEEK. FOR THE MIDDLE TO END OF THE WEEK WESTERLY WINDS ARE
EXPECTED TO INCREASE OVER THE MOUNTAINS AND DESERTS. INCREASING
CHANCES FOR RAIN FROM THE COAST TO THE MOUNTAINS FOR WEDNESDAY AND
THURSDAY.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
SANTA ANA WINDS HAVE WEAKENED SINCE THEIR PEAK YESTERDAY. OVER THE
PAST 12 HOURS THE TOP 3 WIND GUSTS WERE 73 MPH AT HELLHOLE CANYON,
71 MPH AT RANCHO HEIGHTS, AND 70 MPH AT FREEMONT CANYON. LINGERING
GUSTS IN THE 35 TO 55 MPH RANGE CAN BE EXPECTED THROUGH THE
AFTERNOON MOSTLY IN PLACES PRONE TO EASTERLY WINDS. WINDS WILL
BECOME MORE CONFINED TO WIND PRONE LOCATIONS INTO THE EVENING AND
OVERNIGHT HOURS. ABOVE AVERAGE TEMPERATURES CAN BE EXPECTED WEST
OF THE MOUNTAINS TODAY, WITH BELOW AVERAGE TEMPERATURES IN THE
DESERTS. HIGHS SUNDAY WILL RUN 3 TO 7 DEGREES COOLER FOR THE COAST
AND 2 TO 4 DEGREES WARMER FOR INLAND LOCATIONS. THAT COOLING WILL
SPREAD INLAND THROUGH TUESDAY. BY TUESDAY, MOST LOCATIONS WILL
SEE BELOW AVERAGE TEMPERATURES.
MODEL GUIDANCE IS IN GOOD AGREEMENT THAT A CLOSED LOW WILL DIG SOUTH
ALONG THE WEST COAST MONDAY AND TUESDAY, BEFORE SWINGING EAST INTO
SOUTHERN CALIFORNIA TUESDAY NIGHT OR WEDNESDAY. IN ADDITION TO
COOLER CONDITIONS, THIS LOW WILL BRING AN INCREASE IN WESTERLY WINDS
AND RAIN CHANCES. WINDS MAY BEGIN TO INCREASE TUESDAY AFTERNOON,
PEAKING WEDNESDAY OR THURSDAY OVER THE MOUNTAINS AND INTO THE
DESERTS.
RAIN CHANCES ARE IN THE FORECAST AS EARLY TUESDAY EVENING FOR SOME
LOCATIONS, BUT THE MOST LIKELY TIME FOR PRECIPITATION LOOKS TO BE
THIS WEDNESDAY AND THURSDAY. RIGHT NOW, MAINLY LIGHT TO MODERATE
PRECIPITATION IS EXPECTED. ON THURSDAY AS THE LOW MOVES DIRECTLY
OVER SOUTHERN CALIFORNIA IT WILL BRING IT'S ASSOCIATED VORTICITY
WITH IT, INCREASING THE INSTABILITY OF THE ATMOSPHERE. THIS
INTRODUCES A 10 TO 15 PERCENT CHANCE OF THUNDERSTORMS IN THE COASTAL
BASIN. IF THUNDERSTORMS DEVELOP, LOCALLY HEAVY RAIN WILL OCCUR. MOST
PLACES IN AND WEST OF THE MOUNTAINS HAVE A 50 TO 70% CHANCE OF
RAINFALL TOTALS EXCEEDING 0.50", WITH THE SAN BERNARDINO MOUNTAINS
HAVING A HIGHER CHANCE AND AREA DESERTS A LESSER CHANCE. THE PLACE
WITH THE HIGHEST CHANCES OF SEEING 1" OR MORE OF RAIN IS THE SAN
BERNARDINO MOUNTAINS. OVERALL, CONFIDENCE IN RAIN OCCURRING IS HIGH
WITH MODERATE CONFIDENCE IN THE DETAILS.
AVIATION
171800Z...EASTERLY WINDS WILL CONTINUE TO WEAKEN THROUGH THE
AFTERNOON, WITH EASTERLY WINDS 20-35 KTS CONTINUING FOR COASTAL
SLOPES AND PORTIONS OF THE VALLEYS THIS AFTERNOON. WINDS WEAKEN
FURTHER AND BECOME CONFINED TO COASTAL SLOPES AFTER 06Z SUN.
OTHERWISE...VFR CONDITIONS EXPECTED WITH SCT-BKN HIGH CLOUDS THROUGH
TODAY. HIGH CLOUDS SCATTER OUT ACROSS THE AREA TONIGHT.
MARINE
ISOLATED NORTHEAST GUSTS COULD EXCEED 20 KNOTS THROUGH THIS
AFTERNOON. OTHERWISE, NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED
THROUGH WEDNESDAY.
BEACHES
ELEVATED SURF WILL CONTINUE THIS WEEKEND INTO MID-NEXT WEEK WITH
MULTIPLE SOUTH SWELLS MOVING IN THROUGH THIS PERIOD. SURF INCREASES
SLIGHTLY SUNDAY, WITH SURF 3 TO 6 FEET WITH LOCAL SETS TO 7 FEET
(ALONG SOUTH AND SOUTHWEST-FACING BEACHES) THROUGH AT LEAST NEXT
WEDNESDAY.
WHILE SURF AND RIP CURRENTS WILL BE ELEVATED, DAILY HIGH TIDES WILL
NOT BE PARTICULARLY HIGH, AND THE THREAT OF COASTAL FLOODING IS
MINIMAL.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...HEAT ADVISORY UNTIL 8 PM PDT THIS EVENING FOR ORANGE COUNTY
COASTAL AREAS-ORANGE COUNTY INLAND AREAS-SAN DIEGO COUNTY
COASTAL AREAS.
HIGH WIND WARNING UNTIL 8 PM PDT THIS EVENING FOR SAN BERNARDINO
AND RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE-SAN DIEGO
COUNTY VALLEYS.
HIGH WIND WARNING UNTIL MIDNIGHT PDT TONIGHT FOR RIVERSIDE
COUNTY MOUNTAINS-SAN DIEGO COUNTY MOUNTAINS-SAN GORGONIO
PASS NEAR BANNING.
PZ...NONE.
PUBLIC...CO
AVIATION/MARINE/BEACHES...CSP
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