624
FXUS66 KSGX 202145
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
145 PM PST MON JAN 20 2025
SYNOPSIS
MODERATE TO STRONG SANTA ANA WINDS WILL CONTINUE THROUGH TUESDAY
ACROSS THE REGION WITH VERY DRY AIR PLACE, WHICH LEAD TO CRITICAL
FIRE WEATHER CONDITIONS. A QUICK BREAK IN THE WIND WILL OCCUR BY
WEDNESDAY. SANTA ANA WINDS WILL RETURN LATER ON WEDNESDAY INTO
THURSDAY, THOUGH NOT NEARLY AS STRONG AS WE ARE SEEING NOW. AN AREA
OF LOW PRESSURE WILL MOVE IN FROM THE NORTH BY THE WEEKEND, BRINGING
A CHANCE OF PRECIPITATION.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
A LARGE OPEN WAVE TROUGH ACROSS THE COUNTRY THAT IS BRINGING COLD
AND WINTRY WEATHER HAS BROUGHT STRONG OFFSHORE WINDS TO OUR REGION.
MODERATE TO STRONG SANTA ANA WINDS WILL CONTINUE THROUGH THIS
TONIGHT INTO TUESDAY. WINDS WILL TURN MORE EASTERLY BY TONIGHT INTO
TUESDAY MORNING, FAVORING THE STRONGEST WINDS TO IMPACT RIVERSIDE
AND SAN DIEGO COUNTIES. THIS ALONG WITH VERY DRY AIR WILL LEAD TO
CRITICAL TO LOCALLY EXTREME FIRE WEATHER CONDITIONS. PLEASE SEE THE
FIRE WEATHER DISCUSSION BELOW FOR MORE INFORMATION ON THE DETAILS
REGARDING THE WINDS AND HUMIDITY.
THIS HAS ALSO BROUGHT IN COOLER AIR, MAKING FOR CHILLY NIGHTS AND
MORNINGS OVER THE NEXT FEW DAYS. AS IS USUALLY THE CASE, A TOUGH
FORECAST WITH THE LOW TEMPERATURES IS ON THE DOCKET. AREAS THAT ARE
WIND SHELTERED WILL BE ABLE TO SEE RADIATIONAL COOLING, WHERE
TEMPERATURES WILL DROP SIGNIFICANTLY FROM THOSE THAT STAY IN THE
WINDY PATTERN THROUGH THE NIGHT. VALLEYS WEST OF THE MOUNTAINS
THAT DO SEE CALMER WINDS MAY SEE PATCHY FROST THE NEXT COUPLE OF
MORNINGS. HIGH PRESSURE OFF THE COAST WILL MOVE OVER OUR AREA BY
THE MIDDLE OF THE WEEK. THIS WILL ALLOW WARMER WEATHER TO OCCUR AS
HEIGHTS RISE, ESPECIALLY IN OUR HIGHER ELEVATIONS WHERE HIGHS
WILL REACH INTO THE 50S AND 60S AND 70S WEST OF THE MOUNTAINS AND
LOWER DESERTS. DAYTIME HIGHS WILL BE AROUND 5-10 DEGREES ABOVE
NORMAL WITH WARMER NIGHTS.
UPPER LEVEL WINDS RESTRENGTHEN BY ON WEDNESDAY INTO THURSDAY,
WHICH WILL PROVIDE ANOTHER ROUND OF SURFACING SANTA ANA WINDS.
THIS EVENT WILL BE WEAKER AND MORE LOCALIZED TO THE MOUNTAINS AND
FOOTHILLS WITH A MODERATE TO HIGH CHANCE OF SEEING WIND GUSTS OVER
50 MPH IN THESE AREAS. CONFIDENCE IS LOWER ON HOW STRONG WINDS
WILL BE IN ADJACENT VALLEYS, BUT THE WINDS LOOK TO HAVE A GREATER
EASTERLY COMPONENT, WHICH WOULD FAVOR PASSES/CANYONS IN RIVERSIDE
AND SAN DIEGO COUNTIES. ECMWF ENSEMBLES GIVE ROMONA PEAK WIND
GUSTS NEAR 40 MPH, THOUGH SOME MEMBERS HAVE GUSTS CLOSER TO 50
MPH. AS THE SANTA ANA WINDS MOVE OVER THE AREA, TEMPERATURES MAY
WARM A BIT MORE BY THURSDAY OVER THE WESTERN VALLEYS. NBM
PROBABILITIES PAINT A PICTURE OF AROUND A 50-50 CHANCE OF SEEING
HIGHS OVER 80 DEGREES FROM EL CAJON TO ANAHEIM TO TEMECULA.
ANOTHER DEEP TROUGH WILL PUSH INTO THE WEST BY FRIDAY INTO THE
WEEKEND. MODELS ARE STARTING TO BECOME IN BETTER AGREEMENT OF AN
AREA OF LOW PRESSURE CUTTING OFF FROM THE MEAN THE FLOW AND MOVING
OVER OUR REGION BY THE WEEKEND. IF THIS SYSTEM STAYS FAR ENOUGH
WEST, WE WILL SEE AN INCREASED CHANCE OF PRECIPITATION. MODELS AND
ENSEMBLES CONTINUE TO BE WET WITH MEASURABLE PRECIPITATION, BUT HOW
MUCH IS STILL IN QUESTION. THIS SYSTEM ALSO LOOKS TO BE A COLDER
ONE, SO SNOW LEVELS BELOW 4,000 FEET MAY OCCUR AS WELL. LATEST
ENSEMBLE CLUSTERS ARE IN FAIRLY GOOD AGREEMENT OF THE LOW STICKING
INTO THE AREA BY NEXT MONDAY, A BIT LESS SO BY TUESDAY. THE LOW MAY
STICK AROUND EVEN INTO NEXT MONDAY, SO CHANCES FOR PRECIP RAIN IN
THE FORECAST FOR THIS WEEKEND INTO EARLY NEXT WEEK.
AVIATION
202100Z....MANY LOCATIONS ARE CURRENTLY SEEING NORTH/NORTHEASTERLY
SURFACE GUSTS EXCEEDING 35KTS, ESPECIALLY IN THE FOOTHILLS AND
INLAND AREAS, WITH MOUNTAINS/MOUNTAIN PASSES GENERALLY EXCEEDING
50KTS. WINDS SHOULD BEGIN TO GUST AT THE COAST BY 22Z. GUSTS 25-
45KTS WILL PREVAIL THROUGH AT LEAST 06Z REGION-WIDE, WITH LOCALLY
STRONGER GUSTS IN THE FOOTHILLS AND MOUNTAIN PASSES. VERY STRONG
UP/DOWNDRAFTS NEAR THE MOUNTAINS, AND LOCALIZED AREAS OF BLOWING
DUST THAT COULD LEAD TO VIS REDUCTIONS. SLIGHT DECREASE IN WINDS BY
SUNRISE ON TUESDAY, BUT GUSTS EXCEEDING 30KTS WILL CONTINUE THROUGH
AT LEAST TUESDAY EVENING FOR THE MOUNTAINS AND FOOTHILLS.
NWS SAN DIEGO IS AWARE OF LIMITED COMMUNICATIONS OF OBSERVATIONS
FROM KTRM SINCE JANUARY 8TH. WE ARE WORKING WITH THE FAA TO ADDRESS
THIS ISSUE.
MARINE
OFFSHORE WINDS INCREASE THIS AFTERNOON AND EVENING, WITH GUSTS UP TO
25-30KTS AND ASSOCIATED CHOPPY SEAS. WINDS AND SEAS WILL PEAK
TONIGHT, BEFORE GRADUALLY DIMINISHING TUESDAY MORNING. A SMALL CRAFT
ADVISORY IS IN EFFECT AND CONTAINS MORE DETAILS. NO ADDITIONAL
HAZARDOUS MARINE CONDITIONS ARE EXPECTED TUESDAY AFTERNOON THROUGH
FRIDAY.
FIRE WEATHER
MODERATE TO STRONG SANTA ANA WINDS WILL CONTINUE THIS AFTERNOON
THROUGH TUESDAY EVENING, PEAKING IN INTENSITY TONIGHT INTO TUESDAY
MORNING. WIDESPREAD WIND GUSTS OF 35-55 MPH WILL OCCUR ACROSS THE
COASTAL SLOPES OF THE MOUNTAINS AND INTO THE ADJACENT VALLEYS, WITH
LOCAL GUSTS OVER 80 MPH IN THE FAVORED PASSES, CANYONS, AND COASTAL
SLOPES. NORTHERN AREAS LIKE ORANGE COUNTY AND IN FOOTHILLS OF THE
INLAND EMPIRE HAVE LIKELY SEEN THEIR HIGHEST WIND SPEEDS OF THIS
EVENT, THOUGH GUSTY WINDS WILL CONTINUE THROUGH TUESDAY AFTERNOON.
WINDS ARE STILL EXPECTED TO INCREASE ACROSS THE MOUNTAINS AND
FOOTHILLS OF RIVERSIDE AND SAN DIEGO COUNTIES THIS EVENING THROUGH
TUESDAY MORNING AS WINDS TURN MORE EASTERLY. A PERIOD OF EXTREME
FIRE WEATHER CONDITIONS IS LIKELY ACROSS THE COASTAL SLOPES,
FOOTHILLS, AND ADJACENT VALLEYS IN SAN DIEGO COUNTY TUESDAY MORNING
DUE TO THE COMBINATION OF WIND GUSTS IN EXCESS OF 50 MPH AND SINGLE
DIGIT RELATIVE HUMIDITY.
RELATIVE HUMIDITY VALUES HAVE LOWERED NEAR 10-15% THIS AFTERNOON FOR
SOME AREAS ALONG AND WEST OF THE MOUNTAINS. THERE WILL BE VERY
LIMITED OVERNIGHT RECOVERIES TONIGHT AS THE WINDS CONTINUE TO BLOW.
EVEN DRIER AIR WILL MOVE INTO THE AREA BY TUESDAY AFTERNOON WITH
VALUES LOWERING TO 4-7%, POTENTIALLY REMAINING IN THE SINGLE DIGITS
IN THE MOUNTAINS AND FOOTHILLS INTO TUESDAY NIGHT WITH POOR RECOVERY
ELSEWHERE.
SANTA ANA WINDS WILL BE MORE LOCALIZED TO THE MOUNTAINS AND ADJACENT
VALLEYS BY WEDNESDAY. WINDS WILL STRENGTHEN AGAIN ON WEDNESDAY NIGHT
INTO THURSDAY MORNING, PROMPTING ANOTHER INCREASED WILDFIRE WEATHER
RISK. THIS EVENT WILL BE MUCH WEAKER THAN TODAY'S EVENT, BUT WINDS
MAY LOCALLY GUST TO 60 MPH ACROSS THE MOUNTAINS, NEAR 45 MPH IN THE
FOOTHILLS WITH MODERATE CONFIDENCE. THESE WINDS WILL LIKELY WEAKEN
BUT CONTINUE INTO FRIDAY. RELATIVE HUMIDITY WILL REMAIN IN THE
SINGLE DIGITS TO MID TEENS, MAINTAINING NEAR CRITICAL TO CRITICAL
FIRE WEATHER CONDITIONS THURSDAY, AND ELEVATED TO NEAR CRITICAL
CONDITIONS ON FRIDAY. CONDITIONS IMPROVE GREATLY SATURDAY AND SUNDAY
WITH THE RETURN OF ONSHORE FLOW AND A 30-50 PERCENT CHANCE OF
WETTING RAIN AND MOUNTAIN SNOW.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...RED FLAG WARNING UNTIL 10 PM PST TUESDAY FOR ORANGE COUNTY
INLAND AREAS-RIVERSIDE COUNTY MOUNTAINS-INCLUDING THE SAN
JACINTO RANGER DISTRICT OF THE SAN BERNARDINO NATIONAL
FOREST-SAN BERNARDINO COUNTY MOUNTAINS-INCLUDING THE
MOUNTAIN TOP AND FRONT COUNTRY RANGER DISTRICTS OF THE SAN
BERNARDINO NATIONAL FOREST-SAN BERNARDINO AND RIVERSIDE
COUNTY VALLEYS -THE INLAND EMPIRE-SAN DIEGO COUNTY INLAND
VALLEYS-SAN DIEGO COUNTY MOUNTAINS-INCLUDING THE PALOMAR
AND DESCANSO RANGER DISTRICTS OF THE CLEVELAND NATIONAL
FOREST-SAN GORGONIO PASS NEAR BANNING-SANTA ANA MOUNTAINS-
INCLUDING THE TRABUCO RANGER DISTRICT OF THE CLEVELAND
NATIONAL FOREST.
HIGH WIND WARNING FROM 8 PM THIS EVENING TO 8 PM PST TUESDAY FOR
SAN BERNARDINO COUNTY MOUNTAINS-SAN BERNARDINO AND
RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE-SAN GORGONIO
PASS NEAR BANNING-SANTA ANA MOUNTAINS AND FOOTHILLS.
HIGH WIND WARNING FROM 4 AM TO 8 PM PST TUESDAY FOR RIVERSIDE
COUNTY MOUNTAINS-SAN DIEGO COUNTY MOUNTAINS-SAN DIEGO
COUNTY VALLEYS.
FIRE WEATHER WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY
AFTERNOON FOR RIVERSIDE COUNTY MOUNTAINS-INCLUDING THE SAN
JACINTO RANGER DISTRICT OF THE SAN BERNARDINO NATIONAL
FOREST-SAN BERNARDINO COUNTY MOUNTAINS-INCLUDING THE
MOUNTAIN TOP AND FRONT COUNTRY RANGER DISTRICTS OF THE SAN
BERNARDINO NATIONAL FOREST-SAN DIEGO COUNTY INLAND VALLEYS-
SAN DIEGO COUNTY MOUNTAINS-INCLUDING THE PALOMAR AND
DESCANSO RANGER DISTRICTS OF THE CLEVELAND NATIONAL FOREST-
SAN GORGONIO PASS NEAR BANNING-SANTA ANA MOUNTAINS-
INCLUDING THE TRABUCO RANGER DISTRICT OF THE CLEVELAND
NATIONAL FOREST.
PZ...SMALL CRAFT ADVISORY UNTIL 10 AM PST TUESDAY FOR COASTAL WATERS
FROM SAN MATEO POINT TO THE MEXICAN BORDER AND OUT TO 30 NM-
WATERS FROM SAN MATEO POINT TO THE MEXICAN BORDER EXTENDING
30 TO 60 NM OUT INCLUDING SAN CLEMENTE ISLAND.
PUBLIC/FIRE WEATHER...APR
AVIATION/MARINE...ZUBER
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