427
FXUS66 KSGX 281813
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
1013 AM PST SUN DEC 28 2025
SYNOPSIS
WARMER AND DRIER THROUGH TUESDAY WITH PERIODS OF MODERATE GUSTY
SANTA ANA WINDS. A LOW PRESSURE SYSTEM FROM THE SOUTHWEST WILL
LIKELY BRING A RETURN OF PRECIPITATION FOR WEDNESDAY THROUGH NEXT
WEEKEND, THOUGH EXACT TIMING AND PRECIPITATION AMOUNTS ARE STILL
UNCERTAIN.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
THE PATCHES OF SHALLOW RADIATION FOG FROM EARLIER THIS MORNING
HAVE LIFTED AND WE'RE MOSTLY SUNNY WITH VARIABLE HIGH CLOUDS. THE
CLEAR SKIES OVERNIGHT ALLOWED LOW TEMPERATURES TO DROP INTO THE
LOW 30S IN SOME INLAND VALLEY LOCATIONS. SFC PRESSURE GRADIENTS
ARE TRENDING STRONGER OFFSHORE AND ARE CURRENTLY -7.1 MB SAN-TPH
AND -4.0 MB SAN-DAG. WINDS HAVE TURNED OFFSHORE AND THE WINDIEST
LOCATIONS ARE REPORTING NORTHEAST TO EAST WINDS WITH GUSTS 35-45
MPH.
A PATTERN OF HIGH PRESSURE TO THE NORTH AND A CLOSED UPPER LOW TO
THE SOUTHWEST WILL BRING WARM AND DRY CONDITIONS WITH PERIODS OF
GUSTY SANTA ANA WINDS THROUGH TUESDAY. THE OFFSHORE FLOW GETS
SOME UPPER LEVEL SUPPORT ON MON AND TUE WITH NORTHEAST WINDS
ALOFT. THE OFFSHORE FLOW WILL LIKELY BE STRONGEST ON TUESDAY,
PRODUCING GUSTY SANTA ANA WINDS IN THE MTNS AND LOWER ELEVATIONS
WEST OF THE MTNS. NORTHEAST TO EAST WINDS GUSTING 35-45 MPH - WITH
LOCAL GUSTS OF 55-60 MPH - WILL BE POSSIBLE IN THE FAVORED
LOCATIONS. TUESDAY WILL ALSO BE THE WARMEST DAY, WITH HIGH TEMPS
IN THE 70S WEST OF THE MTNS AND MOST AREAS SEEING TEMPS NEAR OR
ABOVE SEASONAL AVERAGES. COASTAL AND VALLEY AREAS COULD BE AS MUCH
AS 9 DEGREES ABOVE AVERAGE WHILE THE MTNS AND DESERTS WILL BE
NEAR OR JUST A FEW DEGREES ABOVE. RELATIVE HUMIDITIES COULD FALL
INTO THE TEENS FOR SOME INLAND AREAS MONDAY AND TUESDAY
AFTERNOONS BUT THE RECENT RAINS WILL MITIGATE FIRE WEATHER
CONCERNS.
CHANCES FOR RAIN AND MOUNTAIN SNOW WILL RETURN FOR WED THROUGH
NEXT WEEKEND AS A LOW PRESSURE SYSTEM MOVES IN FROM THE GULF OF
ALASKA, CAUSING THE CLOSED LOW TO OUR SOUTHWEST TO BECOME AN OPEN
WAVE AS IT IS DRAWN INTO THE MEAN WESTERLY FLOW OVER THE SOUTHWEST
US. FORECAST DETAILS ARE STILL UNCERTAIN BUT NUMERICAL MODEL
SOLUTIONS ARE COMING INTO BETTER AGREEMENT WITH RESPECT TO THE
SYNOPTIC PATTERN. PRECIPITATION COULD MOVE IN AS EARLY AS WED
AFTERNOON WITH PERIODS OF RAIN AND SHOWERS CONTINUING (WITH
BREAKS) THROUGH NEXT 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 0.6"-1.2" IN THE COASTAL AREAS, 0.7"-0.8" IN THE INLAND
VALLEYS, 0.05"-0.4" IN THE LOW DESERTS, 0.15"-0.4" IN THE HIGH
DESERT, 0.55"-1.6" IN THE SAN DIEGO AND RIVERSIDE COUNTY MTNS AND
1.5"-3.5" IN THE SAN BERNARDINO MOUNTAINS. 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
281630Z...VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD WITH A
FEW TO SCATTERED CLOUDS AROUND 25,000 FT MSL. OFFSHORE WINDS OUT OF
THE NORTH TO NORTHEAST WILL GRADUALLY STRENGTHEN THROUGH THE DAY
WITH WIND GUSTS OF 25-30KTS EXPECTED FOR THE COASTAL SLOPES OF THE
MOUNTAINS AND MOUNTAIN PASSES, SPREADING BELOW MOUNTAIN PASSES AND
INTO THE INLAND VALLEYS AFTER 18Z. WHILE GUSTS MAY NOT SURFACE AT
TERMINALS LIKE KONT OR KSBD UNTIL LATE TONIGHT OR MONDAY MORNING,
GUSTY NORTHERLY WINDS BELOW CAJON PASS COULD PRODUCE CROSSWINDS ON
APPROACH/TAKEOFF WITHIN THE INLAND EMPIRE THIS AFTERNOON. LLWS MAY
BE POSSIBLE, ESPECIALLY LATE TONIGHT, FOR INLAND EMPIRE AIRPORTS.
GUSTS STRENGTHEN TO 35-45 KTS FOR THE COASTAL MOUNTAIN SLOPES AND
PASSES AFTER 00-02Z MONDAY WITH MOD UP/DOWNDRAFTS EXPECTED. STRONG
OFFSHORE WINDS PREVAIL INTO MONDAY EVENING.
MARINE
NO HAZARDOUS MARINE WEATHER CONDITIONS EXPECTED THROUGH FRIDAY.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...HIGH WIND WATCH FROM THIS EVENING THROUGH TUESDAY AFTERNOON 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 WATCH FROM LATE TONIGHT THROUGH TUESDAY AFTERNOON FOR
SAN DIEGO COUNTY MOUNTAINS-SAN DIEGO COUNTY VALLEYS.
PZ...NONE.
PUBLIC...PG
AVIATION/MARINE...VILLAFANE
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