529
FXUS66 KSGX 200529
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
929 PM PST WED FEB 19 2025
SYNOPSIS
WEAK OFFSHORE FLOW WILL BRING WARMER CONDITIONS TO THE COAST AND
VALLEYS ON THURSDAY AND FRIDAY, WITH A FEW DEGREES OF COOLING
IN THE MOUNTAINS AND DESERTS. GUSTY NORTH TO NORTHEAST WINDS
WILL OCCUR ALONG AND BELOW THE COASTAL SLOPES OF THE MOUNTAINS
WITH GUSTS 35 MPH TO 45 MPH, LOCALLY UP TO 50 MPH. PATCHY LOW
CLOUDS AND FOG IS EXPECTED FOR THE NEXT FEW NIGHTS NEAR THE
COAST. WIDESPREAD ABOVE AVERAGE TEMPERATURES ARE EXPECTED FOR
SATURDAY THROUGH NEXT WEDNESDAY.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
THIS EVENING...A FEW HIGH CLOUDS ARE MOVING OFF TO THE EAST AND A
COUPLE OF PATCHES OF MARINE LAYER LOW CLOUDS AND FOG ARE LINGERING
NEAR THE IMMEDIATE COAST OVER NORTHERN SAN DIEGO COUNTY.
OTHERWISE, SKIES ARE MOSTLY CLEAR. THE MARINE LAYER IS VERY
SHALLOW WITH A RELATIVELY WEAK INVERSION, HOWEVER SEVERAL HIGH-
RESOLUTION SHORT-RANGE MODELS SHOW PATCHES OF LOW CLOUDS AND FOG
PERSISTING OVER THE COASTAL AREAS AT TIMES THROUGH TONIGHT.
FROM PREVIOUS DISCUSSION...
THERE IS A CHANCE FOR LOW CLOUDS AND FOG AGAIN THURSDAY NIGHT
INTO FRIDAY. LOW CLOUDS BECOME LESS LIKELY OVER THE WEEKEND AND
FOR THE BEGINNING OF NEXT WEEK. WEAK OFFSHORE FLOW IS EXPECTED
FOR THURSDAY AND FRIDAY WHICH COULD REDUCE THE CHANCES FOR
SIGNIFICANT LOW CLOUDS AND FOG. FOR THURSDAY MORNING INTO THURSDAY
NIGHT, THERE WILL BE GUSTY NORTHERLY WINDS ALONG AND BELOW THE
COASTAL SLOPES OF THE MOUNTAINS WITH THE STRONGER GUSTS OF 40 TO
50 MPH NEAR THE CAJON PASS. THE WINDS WILL BECOME MORE
NORTHEASTERLY BY FRIDAY MORNING, SPREADING SOUTHWARD IN SAN DIEGO
COUNTY AND CONTINUING INTO FRIDAY AFTERNOON WITH THE STRONGER
GUSTS OF 30 TO 40 MPH.
THERE WILL BE WARMING FOR THE COAST AND VALLEYS THROUGH FRIDAY WITH
THE GREATER WARMING FOR THURSDAY AND FRIDAY. THE MOUNTAINS AND
DESERTS WILL BE A FEW DEGREES COOLER ON THURSDAY AND ANOTHER DEGREE
OR TWO COOLER ON FRIDAY. HIGH PRESSURE ALOFT WILL BUILD ACROSS
SOUTHERN CALIFORNIA SATURDAY THROUGH NEXT WEDNESDAY. THE NATIONAL
BLEND OF MODELS GUIDANCE FOR TUESDAY SHOWS A 40 PERCENT CHANCE OF
THE LOW DESERTS EXCEEDING 90 DEGREES, A 30 TO 40 PERCENT CHANCE
OF THE VALLEYS EXCEEDING 85 DEGREES, A 40 PERCENT CHANCE OF
COASTAL AREAS EXCEEDING 75 DEGREES, AND A 40 TO 60 PERCENT FOR
MOUNTAINS BELOW 5000 FEET EXCEEDING 75 DEGREES. THE GUIDANCE ALSO
INDICATES WEDNESDAY WILL BE A FEW DEGREES COOLER THAN TUESDAY FOR
MOST LOCATIONS, BUT ECMWF ENSEMBLE GUIDANCE INDICATES WARMING
CONDITIONS THROUGH THURSDAY. CURRENT FORECAST KEEPS HIGH
TEMPERATURES 10 TO 20 DEGREES ABOVE AVERAGE AWAY FROM THE COAST
SUNDAY THROUGH WEDNESDAY.
AVIATION
200400Z...COAST...MOSTLY CLEAR SKIES THROUGH LATE TONIGHT EXCEPT FOR
PASSING HIGH CLOUDS. PATCHY LOW CLOUDS AND FOG ARE EXPECTED TO FORM
JUST ALONG COASTAL REGIONS WITHIN 5 MILES OF THE COAST, WITH BASES
200-800 FT MSL. LOW CONFIDENCE IN IMPACTS AND TIMING TO TAF SITES,
AS AREAS OF LOW CLOUDS THAT DO DEVELOP WILL BE HIT-AND-MISS IN
NATURE. THERE IS A 50% CHANCE FOR CIGS AT KSAN AND KSNA BY 09-10Z
TONIGHT, INCREASING TO 60% BY 12-13Z, WITH LOWER CHANCES (30-50%)
ELSEWHERE. WHERE LOW CLOUDS/FOG DO DEVELOP, VIS IMPACTS ARE LIKELY,
DOWN TO 1-4 SM FOR COASTAL SITES, LOCALLY LOWER FOR COASTAL
HIGHLANDS/MESAS. THERE IS A 20-30% CHANCE FOR VIS LOWER THAN 1 SM
FOR COASTAL SITES 13-16Z THIS MORNING. LOW CLOUDS/FG RETREAT TO THE
BEACHES 15-17Z WHERE THEY MAY LINGER IN AREAS THROUGH THE EARLY
AFTERNOON.
VALLEYS/MOUNTAINS/DESERTS...FEW-SCT HIGH CLOUDS ABOVE 25,000 FT MSL
AND VFR CONDITIONS THROUGH THURSDAY. NORTH-NORTHEAST TO EASTERLY
WINDS WILL STRENGTHEN OVER MOUNTAINS AND FOOTHILLS/IN DESERTS AND
PARTS OF THE INLAND EMPIRE (GENERALLY AREAS BELOW/SOUTH OF THE CAJON
PASS) THURSDAY AFTERNOON, REMAINING INTERMITTENTLY GUSTY THROUGH THE
PERIOD. GUSTS TO 25-40 KTS AND MOD UP/DOWNDRAFTS NEAR AND OVER
MOUNTAINS.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE ANTICIPATED THROUGH SATURDAY.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...NONE.
PUBLIC...PG
AVIATION/MARINE...CSP
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