990
FXUS66 KSGX 290452
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
852 PM 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, AND
ANOTHER FROM THE GULF OF ALASKA, 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...
EVENING UPDATE...
A FEW THIN HIGH CLOUDS WERE MOVING OVER THE REGION THIS EVENING.
OFFSHORE SURFACE PRESSURE GRADIENTS CONTINUE TO STRENGTHEN,
CURRENTLY AT -12 MB SAN-TPH AND -6 MB SAN-DAG. THE STRONGEST WINDS
ARE OCCURRING NEAR THE CAJON PASS WHERE GUSTS RANGE ANYWHERE FROM
40-60 MPH, WITH ISOLATED GUSTS AS HIGH AS 68 MPH. WINDS WILL PEAK
LATE TONIGHT INTO MONDAY, WITH A SECOND PEAK FOR AREAS PRONE TO
EASTERLY WINDS (SAN GORGONIO PASS AND SAN DIEGO COUNTY) LATE
MONDAY INTO TUESDAY MORNING. NO CHANGES TO THE FORECAST THIS
EVENING, THOUGH WE CONTINUE TO MONITOR THE INCOMING STORM FOR NEW
YEAR'S EVE AND NEW YEAR'S DAY.
PREVIOUS DISCUSSION...
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. CURRENT SOLUTIONS INDICATE THAT SOCAL WILL
RECEIVE PRECIPITATION IN TWO PHASES. THE CLOSED LOW EJECTING TO
THE NORTHEAST FROM ITS POSITION ABOUT 1100 MILES TO OUR SOUTHWEST
WILL LIKELY BRING PERIODS OF RAIN/SHOWERS IN A WARM ENVIRONMENT LATE
WED THROUGH THU. A DYNAMIC RIDGE BETWEEN THE EXITING LOW/TROUGH
AND THE LOW APPROACHING FROM THE GULF OF AK COULD PROVIDE A BREAK
FROM THE PRECIP ON FRIDAY. THE LOW FROM THE GULF OF AK WILL RESUME
THE RAIN/SHOWERS IN A COLDER ENVIRONMENT FOR SAT THROUGH SUN.
PRECIPITATION COULD MOVE IN AS EARLY AS LATE WED MORNING 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
1"-1.9" IN THE COASTAL AREAS, 1.2"-2" IN THE INLAND VALLEYS,
0.10"-0.7" IN THE LOW DESERTS, 0.40"-0.9" IN THE HIGH DESERT,
1.3"-3.5" IN THE SAN DIEGO AND RIVERSIDE COUNTY MTNS AND
1.8"-4.5" 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
290500Z...VFR CONDITIONS CONTINUE THROUGH THE TAF PERIOD WITH FEW-
SCT HIGH CLOUDS AOA 25,000FT. GUSTY OFFSHORE WINDS OUT OF THE NORTH
TO NORTHEAST WILL CONTINUE TO GRADUALLY STRENGTHEN OVERNIGHT INTO
MONDAY AFTERNOON WITH WIND GUSTS OF 35-45KTS FOR THE COASTAL
MOUNTAIN SLOPES AND MOUNTAIN PASSES WITH 20-30KT GUSTS STRETCHING
BELOW MOUNTAIN PASSES INTO INLAND VALLEYS. 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 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 INTO MONDAY EVENING.
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...SS/PG
AVIATION/MARINE...MUNYAN
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