555
FXUS66 KSGX 152016
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
116 PM PDT THU OCT 15 2026
SYNOPSIS
SANTA ANA WINDS EXPECTED TODAY THROUGH SATURDAY, WITH THE
STRONGEST AND MOST WIDESPREAD WINDS ON FRIDAY. ADDITIONALLY,
MODERATE TO MAJOR HEATRISK IS EXPECTED FOR COASTAL AREAS. COOLER
CONDITIONS WILL SPREAD INLAND SUNDAY AS SANTA ANAS WEAKEN, WITH
GREATER COOLING AND CHANCE OF SHOWERS NEXT TUESDAY THROUGH NEXT
THURSDAY.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
SHORT TERM...TODAY THROUGH SATURDAY, OCT 17
MID-LEVEL LOW
PRESSURE HAS SETTLED INTO WESTERN AZ AND SOUTHEASTERN CA, WITH A
STRONG SURFACE HIGH PRESSURE IN THE NORTHERN INTERMOUNTAIN WEST.
THIS HAS RESULTED IN MODERATELY TO LOCALLY QUITE STRONG SANTA ANA
WINDS FROM THE NORTHEAST. FAIRLY WIDESPREAD OFFSHORE WINDS ARE
BROADLY GUSTING 15 TO 30 MPH EVEN TOWARDS SOME OF THE COASTAL
AREAS (ESPECIALLY IN ORANGE COUNTY), WITH GUSTS TOWARDS 25 TO 40
MPH ALONG THE FOOTHILLS INTO THE INLAND VALLEYS, INCLUDING THE
INLAND EMPIRE. OUR TYPICALLY GUSTY CANYONS AND MOUNTAIN PASSES
ARE, AS PER USUAL, WINNING THE GUST- OFF WITH PEAK GUSTS 45 TO 60
MPH.
THE STRONG DOWNWARD MOTION OF THESE WINDS HAS LEAD TO MUCH WARMER
TEMPERATURES THAN YESTERDAY FROM THE FOOTHILLS TO THE COAST. IN
TERMS OF CHANGE IN TEMPERATURE FROM YESTERDAY, TEMPERATURES THIS
AFTERNOON ARE ANYWHERE FROM 5 TO 20 DEGREES WARMER IN THIS AREA,
WITH HIGHS FROM 80 TO JUST ABOVE 90 DEGREES. WHILE TEMPERATURES IN
THE VALLEYS AND COASTAL REGIONS ARE 5 TO 15 DEGREES ABOVE AVERAGE,
TEMPERATURES IN THE MOUNTAINS AND DESERTS ARE ACTUALLY BELOW
AVERAGE THANKS TO THE COLDER AIR MASS MOVING INTO THE REGION. THIS
HAS ALSO LEAD TO LOWER HUMIDITY, WITH VALUES GENERALLY 20-25% IN
THE VALLEYS/NON-IMMEDIATE COAST AND LOCALIZED AREAS AROUND
15-20%.
SURFACE HIGH PRESSURE GRADUALLY MOVES SOUTHWARD INTO THE GREAT
PLAINS TONIGHT INTO FRIDAY AS THE MID-LEVEL LOW MOVES SOUTHWEST.
THIS WILL TURN OFFSHORE WINDS FROM NORTHEAST TO MORE DUE EASTERLY,
WHICH WILL LEAD TO STRONGER AND MORE WIDESPREAD WINDS FOR THE
EAST INLAND EMPIRE AND SAN DIEGO AND ORANGE COUNTIES FRIDAY, WHILE
WINDS IN THE SAN BERNARDINO MTN FOOTHILLS INTO THE NORTHERN IE
WILL WEAKEN SLIGHTLY, THOUGH REMAIN GUSTY. WINDS WILL BE IN THE 20
TO 30 MPH RANGE WITH GUSTS 45 TO 60 MPH FOR FOOTHILLS AND INLAND
VALLEYS, WHILE COASTAL AREAS WILL SEE GUSTS CLOSER TO 15 TO UP TO
ABOUT 30 MPH. THIS WILL DRIVE TEMPERATURES EVEN WARMER FOR FRIDAY,
ESPECIALLY FOR COASTAL REGIONS. LOW TEMPERATURES IN THIS REGION
WILL STRUGGLE TO DIP FAR BELOW 70 DEGREES, WITH HIGHS IN THE MID
80S TO MID 90S.
THIS FLOW PATTERN WILL ACTUALLY HELP TO DRAG SOME MOISTURE FROM
THE SOUTH/SOUTHEAST INTO THE REGION FRIDAY, SO UNLIKE THE
TYPICAL SANTA ANA PATTERN WHERE STRONGER WINDS = DRIER CONDITIONS,
HUMIDITY WILL ACTUALLY INCREASE SLIGHTLY FOR FRIDAY. THIS, ALONG
WITH RECENT SUBSTANTIAL RAINFALL, WILL HELP TEMPER THE DANGER FOR
FIRE WEATHER, THOUGH CONDITIONS WILL BE ELEVATED TO LOCALLY NEAR
CRITICAL FOR FIRE WEATHER THROUGH SATURDAY. THIS MOISTURE WILL
ALSO LEAD TO INCREASED CLOUD COVER FOR FRIDAY INTO SATURDAY, AND
EVEN LEAD TO THE POSSIBILITY OF ELEVATED STORMS LATE FRIDAY INTO
SATURDAY. THE MAJORITY OF PRECIPITATION WILL EVAPORATE IN THE DRY
LAYER BENEATH THE CLOUD, BUT THERE'S ABOUT A 10% CHANCE FOR SOME
VERY LIGHT PRECIPITATION DURING THIS TIME PERIOD, MOSTLY FOR THE
MOUNTAINS/DESERTS AND PERHAPS FOR FAR SOUTH-CENTRAL/SOUTHEASTERN
SAN DIEGO CO. THERE WILL BE A LITTLE BIT OF ELEVATED INSTABILITY
(MUCAPE ~100-300 J/KG) THAT COULD RESULT IN AN ISOLATED
THUNDERSTORM, BUT CHANCES LOOK PRETTY SMALL (AROUND 5%).
SATURDAY, THE CENTRAL U.S. RIDGE AND ASSOCIATED SURFACE HIGH
WEAKENS AND SHIFTS EASTWARDS, AND OFFSHORE WINDS WILL WEAKEN,
THOUGH THEY'LL BE BREEZY. TEMPERATURES WILL DECREASE A FEW
DEGREES.
LONG TERM...SUNDAY, OCT 18 THROUGH FRIDAY, OCT 23
AS THE HIGH
CONTINUES ITS EASTWARD SHUFFLE, WINDS CONTINUE TO WEAKEN LATE
SATURDAY INTO SUNDAY, SO WHILE WINDS WILL BE OFFSHORE SUNDAY
MORNING, THEY WILL BE MUCH WEAKER. WINDS WILL SWITCH TO ONSHORE
SUNDAY AFTERNOON, BRING ADDITIONAL COOLING, A TREND THAT WILL
CONTINUE INTO MONDAY AS WEAK LOW PRESSURE HANGS OUT IN SOUTHERN
CALIFORNIA. AT LEAST PATCHY MARINE LAYER LOW CLOUDS WILL LIKELY
RETURN MONDAY MORNING, RESULTING IN PATCHY COASTAL FOG.
A LARGE- SCALE, STRONGER MID- LEVEL LOW PRESSURE SYSTEM STARTS
MOVING DOWN FROM THE GULF OF ALASKA LATE MONDAY INTO TUESDAY,
BRINGING BREEZIER ONSHORE FLOW AND EVEN COOLER TEMPERATURES FOR
TUESDAY, ALONG WITH A CHANCE FOR SHOWERS THAT WILL INCREASE FROM
NORTH TO SOUTH LATER TUESDAY INTO WEDNESDAY MORNING. GLOBAL
WEATHER MODELS ALREADY HAVE PRETTY GOOD AGREEMENT ON TIMING OF THE
TROUGH, WITH THE LARGE MAJORITY OF ENSEMBLE MEMBERS AGREEING ON
WIDESPREAD RAIN SHOWERS. THERE ARE SOME LOCATION DIFFERENCES IN
THE TROUGH PLACEMENT WHICH IS LEADING TO DIFFERENCES IN HOW MUCH
PRECIPITATION EXACTLY, BUT AT THIS RANGE PRECIPITATION IS LOOKING
LIGHT TO LOCALLY MODERATE. TEMPERATURES WILL CONTINUE TO DECREASE
THROUGH WED-THU, WITH HIGHS IN THE 60S-70S FOR THE COASTAL
BASIN/HIGH DESERTS, 40-55 FOR THE MOUNTAINS, AND MID 70S IN THE
LOW DESERTS. BREEZY ONSHORE WINDS ARE LIKELY FOR TUESDAY INTO
WEDNESDAY IN THE USUAL AREAS (COASTAL WATERS, MOUNTAINS AND DESERT
FOOTHILLS). KEEP YOUR EYE ON THE FORECAST THIS UPCOMING WEEK.
MODELS DIVERGE FRIDAY INTO NEXT WEEKEND, BUT GENERAL AGREEMENT IS IN
SOME STRENGTH OF LARGE-SCALE MID-LEVEL TROUGHING CONTINUING, SO
WHILE ANY PRECIP WILL LIKELY TAPER OFF BY LATE NEXT THURSDAY,
TEMPERATURES LOOK TO REMAIN IN THE COOL TO AVERAGE ZONE THROUGH
NEXT WEEK.
AVIATION
151830Z...SKC AND VFR THROUGH FRI. NORTHEAST WINDS WILL REMAIN
ELEVATED INTO FRI, WHEN THE STRONGEST AND MOST WIDESPREAD WINDS ARE
EXPECTED. FOR THE MOUNTAIN FOOTHILLS PEAK GUSTS OF 45 TO 55 KT ARE
EXPECTED. FOR THE VALLEYS, GUSTS 30 TO 45 KT, LOCALLY HIGHER NEAR
MOUNTAIN FOOTHILLS ARE LIKELY. COAST AND COACHELLA VALLEY WILL ALSO
SEE ELEVATED WINDS WITH GUSTS 20 TO 30 KT. THERE IS A POTENTIAL FOR
GUSTS OF 50 KT TO OCCUR AT KONT EARLY FRI AM. WINDS MAY DECREASE
BRIEFLY AFTER 00Z FRI, INCREASING AROUND 10Z FRI. WINDS FRI WILL
WEAKEN FROM NORTH TO SOUTH 18-22Z. 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. EAST WINDS CONTINUE INTO SAT.
MARINE
ISOLATED NORTHEAST GUSTS COULD EXCEED 20 KNOTS FRIDAY INTO EARLY
SATURDAY. OTHERWISE, NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED
THROUGH MONDAY.
BEACHES
A SOUTH SWELL FROM 190 TO 200 DEGREES AT 3 TO 4 FEET WITH A 15-17
SECOND PERIOD WILL GENERATE ELEVATED SURF OF 3 TO 6 FEET, WITH LOCAL
SETS TO 7 FEET. THERE IS AN INCREASED RISK OF STRONG RIP CURRENTS.
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 UNTIL 8 PM PDT SATURDAY FOR ORANGE COUNTY COASTAL
AREAS-ORANGE COUNTY INLAND AREAS-SAN DIEGO COUNTY COASTAL
AREAS.
HIGH WIND WARNING UNTIL 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 UNTIL 8 PM PDT FRIDAY FOR SAN BERNARDINO
COUNTY MOUNTAINS.
HIGH WIND WARNING UNTIL MIDNIGHT PDT SATURDAY NIGHT FOR
RIVERSIDE COUNTY MOUNTAINS-SAN DIEGO COUNTY MOUNTAINS-SAN
GORGONIO PASS NEAR BANNING.
HIGH WIND WARNING UNTIL NOON PDT SATURDAY FOR SANTA ANA
MOUNTAINS AND FOOTHILLS.
WIND ADVISORY UNTIL NOON PDT SATURDAY FOR ORANGE COUNTY INLAND
AREAS.
PZ...NONE.
PUBLIC...CSP
AVIATION/MARINE/BEACHES...CO
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