684
FXUS66 KSGX 292127
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
127 PM PST MON DEC 29 2025
SYNOPSIS
DRY AND WARM WEATHER CONTINUES INTO TUESDAY WITH INCREASED SANTA
ANA WINDS ACROSS THE MOUNTAINS AND WESTERN VALLEYS. CLOUDIER SKIES
WILL ENTER THE REGION TUESDAY AS LOW PRESSURE SYSTEMS OVER THE
EASTERN PACIFIC MOVE OVER OUR AREA. THIS WILL BRING CHANCES FOR
PERIODS OF RAIN AND SHOWERS FOR NEW YEAR'S EVE THROUGH THE
WEEKEND.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
THIS AFTERNOON...SKIES ARE MOSTLY CLEAR. SFC PRESSURE GRADIENTS
REMAIN STRONGLY OFFSHORE WITH -14.0 MB SAN-TPH AND -8.3 MB SAN-
DAG. SANTA ANA WINDS CONTINUE AND LOCATIONS IN THE WIND-PRONE
AREAS HAVE REPORTED WIND GUSTS OF 45-55 MPH WITH LOCALLY HIGHER
GUSTS TO 70 MPH.
WITH AN UPPER-LEVEL HIGH PRESSURE RIDGE TO THE NORTH AND A CLOSED
UPPER LOW ABOUT 400 MILES SOUTHWEST OF SAN DIEGO RETROGRADING TO
THE SOUTHWEST, DRY AND WARM WEATHER WILL CONTINUE THROUGH TUESDAY.
PERIODS OF GUSTY SANTA ANA WINDS WILL ALSO CONTINUE THROUGH
TUESDAY. NORTHEAST TO EAST WINDS WILL CONTINUE TO GUST 45-55 MPH
WITH LOCALLY HIGHER GUSTS IN WINDS-PRONE AREAS. TUESDAY WILL
LIKELY BE THE WARMEST DAY WITH TEMPERATURES IN THE 70S TO NEAR 80
WEST OF THE MTNS. MOST AREAS WILL BE NEAR TO AS MUCH AS 11 DEGREES
ABOVE SEASONAL AVERAGES. THE TEMPERATURE FORECAST FOR TUESDAY MAY
BE COMPLICATED BY HIGH CLOUDS MOVING IN FROM THE SOUTHWEST AND
REDUCING DAYTIME SOLAR HEATING BUT THE INCREASING HEIGHTS AND
THICKNESSES WILL TEND TO RAISE TEMPERATURES.
BY TUESDAY, THE RETROGRADING UPPER-LEVEL CLOSED LOW OFF THE COAST
WILL MERGE WITH THE CLOSED LOW ABOUT 1200 MILES SOUTHWEST OF SAN
DIEGO. BY WEDNESDAY THIS NEW LOW WILL BEGIN TO MOVE NORTHEAST
TOWARD SOCAL AS A LOW PRESSURE SYSTEM MOVES SOUTHWARD OUT OF THE
GULF OF AK. THESE SYSTEMS WILL BRING US PERIODS OF RAIN/SHOWERS
FROM LATE WED THROUGH THE WEEKEND. THIS WILL LIKELY OCCUR IN TWO
DISTINCT PHASES. THE FIRST PHASE WILL BE THE LOW TO THE SOUTHWEST
EJECTING TO THE NORTHEAST AND BECOMING AN OPEN WAVE OVER SOCAL ON
THU. DURING THIS PHASE, RELATIVELY WARM, MOIST AIR FROM THE
TROPICS WILL RESULT IN WIDESPREAD RAIN/SHOWERS BEFORE A DYNAMIC
RIDGE MOVES OVER THE REGION ON FRIDAY. THIS RIDGE COULD BRING A
BREAK IN THE PRECIPITATION UNTIL THE LOW FROM THE GULF OF AK
ARRIVES WITH COLDER AIR AND MORE RAIN/SHOWERS FOR SAT THROUGH
MONDAY. SNOW LEVELS WILL REMAIN ABOVE 8,000 FT THROUGH FRIDAY THEN
FALL TO AROUND 7,500 FT ON SAT AND 6,500 FT ON SUNDAY.
PRECIP AMOUNTS WILL BE GREATEST IN THE NORTHERN AREAS
(ORANGE AND SAN BERNARDINO COUNTIES) AND LESS IN SOUTHERN SAN
DIEGO COUNTY. CURRENT RAINFALL ESTIMATES ARE FOR TOTALS OF
0.9"-1.9" IN THE COASTAL AREAS, 1.1"-1.6" IN THE INLAND VALLEYS,
0.1"-0.6" IN THE LOW DESERTS, 0.1"-0.6" IN THE HIGH DESERT,
1.1"-2" IN THE SAN DIEGO AND RIVERSIDE COUNTY MTNS AND 1.5"-5.0"
IN THE SAN BERNARDINO MOUNTAINS. MOST OF THE PRECIP WILL BE
CONCENTRATED ALONG THE COASTAL SLOPES OF THE SAN BERNARDINO
MOUNTAINS WEST OF THE CAJON PASS. THE SNOW LEVEL WILL REMAIN
ABOVE 8,000 FT THROUGH FRIDAY BEFORE LOWERING TO AROUND 6,500 FT
ON SATURDAY. MOST OF THE PRECIPITATION WILL LIKELY FALL BEFORE
NEXT WEEKEND SO SNOWFALL AMOUNTS AT RESORT LEVELS AND BELOW WILL
BE LIMITED.
AVIATION
292100Z...VFR CONDITIONS THROUGH THE TAF PERIOD WITH FEW TO
SCATTERED HIGH CLOUDS AROUND 25,000 FT MSL. HIGH CLOUDS WILL
INCREASE IN COVERAGE THIS EVENING AND OVERNIGHT TO BECOME BKN TO OVC
FOR TUESDAY. GUSTY WINDS CONTINUE OUT OF THE NORTH TO NORTHEAST WITH
GUSTS OF 35-45 KTS FOR THE COASTAL MOUNTAIN SLOPES AND MOUNTAIN
PASSES AND 20-30 KT GUSTS STRETCHING BELOW MOUNTAIN PASSES INTO
INLAND VALLEYS. LOCALIZED AREAS OF REDUCED VIS DUE TO BLDU IS
POSSIBLE, ESPECIALLY NEAR THE MOUNTAINS. GUSTY NORTHERLY WINDS BELOW
CAJON PASS COULD PRODUCE CROSSWINDS ON APPROACH/TAKEOFF WITHIN THE
INLAND EMPIRE ALONG WITH 25-35 KTS OF LOW LEVEL WIND SHEAR.
WIDESPREAD MOD UP/DOWNDRAFTS EXPECTED, ESPECIALLY NEAR MOUNTAINS AND
MOUNTAIN PASSES. STRONG OFFSHORE WINDS PREVAIL THROUGH LATE
TUESDAY MORNING.
MARINE
NO HAZARDOUS MARINE WEATHER CONDITIONS EXPECTED THROUGH SATURDAY.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...WIND ADVISORY UNTIL 1 PM PST TUESDAY FOR SAN BERNARDINO COUNTY
MOUNTAINS-SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE
INLAND EMPIRE-SAN DIEGO COUNTY MOUNTAINS-SAN DIEGO COUNTY
VALLEYS-SAN GORGONIO PASS NEAR BANNING-SANTA ANA MOUNTAINS
AND FOOTHILLS.
PZ...NONE.
PUBLIC...PG
AVIATION/MARINE...VILLAFANE
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