796
FXUS66 KSGX 280021
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
421 PM PST SAT DEC 27 2025
SYNOPSIS
AREAS OF CUMULUS CLOUDS ALONG AND WEST OF THE COASTAL MOUNTAIN
SLOPES THIS AFTERNOON WILL CLEAR OVERNIGHT. A DRYING PATTERN WILL
DEVELOP FOR SUNDAY THROUGH TUESDAY, WITH PERIODS OF WEAK TO
MODERATE STRENGTH GUSTY SANTA ANA WINDS. SLIGHT WARMING WILL
ACCOMPANY THE OFFSHORE FLOW FOR MONDAY AND TUESDAY. A LOW PRESSURE
SYSTEM FROM THE SOUTHWEST COULD BRING A RETURN OF PRECIPITATION
FOR WEDNESDAY THROUGH NEXT SATURDAY.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
4 PM AFTERNOON UPDATE...
A HIGH WIND WATCH HAS BEEN ISSUED FOR THE SAN BERNARDINO COUNTY
MOUNTAINS, THE INLAND EMPIRE, AND THE BANNING PASS STARTING 10 PM
SUNDAY EVENING, AND FOR THE SAN DIEGO COUNTY MOUNTAINS AND SAN
DIEGO COUNTY VALLEYS STARTING 4 AM MONDAY MORNING. THESE HIGH WIND
WATCHES ARE IN EFFECT THROUGH 1 PM TUESDAY. MORE DETAILS ABOUT THE
OFFSHORE WINDS CAN BE FOUND FROM THE PREVIOUS DISCUSSION BELOW AND
THE HIGH WIND WATCH PRODUCT.
THE AVIATION SECTION OF THE DISCUSSION HAS ALSO BEEN UPDATED FOR
THE 00Z TAF PACKAGE.
PREVIOUS DISCUSSION...
THIS AFTERNOON...AREAS OF LOW CLOUDS FORMED ALONG THE COASTAL MTN
SLOPES, AND IN THE COASTAL AREAS AND VALLEYS. THE CLOUDS WILL
LIKELY CLEAR TONIGHT SO TEMPERATURES COULD FALL INTO THE 30S IN
PARTS OF THE INLAND VALLEYS EARLY SUNDAY MORNING
DRY AND WARMER CONDITIONS ARE EXPECTED FOR SUNDAY THROUGH TUESDAY
AS HIGH PRESSURE BUILDS OVER THE WEST COAST AND A POSITIVELY-
TILTED TROUGH EXTENDS TO THE SOUTHWEST OVER SOCAL WITH A CLOSED
UPPER LOW FORMING TO OUR SOUTHWEST. OFFSHORE FLOW DEVELOPS ON
SUNDAY AND PERSISTS THROUGH TUESDAY AS A SFC HIGH MOVES INTO THE
GREAT BASIN. 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 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 7
DEGREES ABOVE AVERAGE WHILE THE MTNS AND DESERTS WILL BE NEAR OR
JUST A FEW DEGREES ABOVE.
CHANCES FOR RAIN AND MOUNTAIN SNOW WILL RETURN FOR WED THROUGH
NEXT SAT 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 DUE TO DIFFERENCES IN
MODEL SOLUTIONS BUT IT'S LIKELY THAT WE WILL SEE PERIODS OF
SHOWERS BETWEEN WED AND NEXT SAT. THE TIMING IS ALSO IN QUESTION
BUT PRELIMINARY ESTIMATES ARE FOR TOTALS OF 1"-1.5" IN THE
COASTAL AREAS AND VALLEYS, 1"-3" IN THE MTNS, 0.3"-0.6" IN THE
HIGH DESERTS AND 0.15"-0.30" IN THE LOW DESERTS. THE SNOW LEVEL
WILL REMAIN ABOVE 8,000 FT THROUGH FRIDAY BEFORE LOWERING TO
AROUND 6,500 FT ON SAT.
AVIATION
280000Z...VFR CONDITION ARE EXPECTED THROUGH THE TAF PERIOD.
LINGERING CUMULUS CLOUDS BASED 3000-5000FT MSL ACROSS THE INLAND
INLAND VALLEYS AND MOUNTAINS WILL DISSIPATE THIS EVENING, GIVING WAY
TO MOSTLY CLEAR SKIES OTHER THAN FEW-SCT HIGH CIRRUS AOA
25,000FT.
NORTH-NORTHEASTERLY OFFSHORE WINDS PICK UP AFTER 12Z SUNDAY,
GRADUALLY STRENGTHENING SUNDAY AFTERNOON/EVENING. WIND GUSTS OF 25-
30KTS EXPECTED FOR THE COASTAL SLOPES OF THE MOUNTAINS AND MOUNTAIN
PASSES FROM 12-18Z, SPREADING BELOW MOUNTAIN PASSES AND INTO THE
INLAND VALLEYS AFTER 18Z. WHILE GUSTS MAY NOT SURFACE AT TERMINALS
LIKE KONT OR KSBD UNTIL LATE SUNDAY NIGHT OR MONDAY, GUSTY NORTHERLY
WINDS BELOW CAJON PASS COULD PRODUCE CROSSWINDS ON APPROACH/TAKEOFF
WITHIN THE INLAND EMPIRE SUNDAY AFTERNOON. GUSTS STRENGTHEN TO 35-45
KTS FOR THE COASTAL MOUNTAIN SLOPES AND PASSES HIGHER GUSTS THROUGH
MOUNTAIN PASSES AFTER 00Z MONDAY WITH MOD UP/DOWNDRAFTS EXPECTED.
STRONG OFFSHORE WINDS PREVAIL INTO MONDAY AFTERNOON.
MARINE
NO HAZARDOUS MARINE WEATHER CONDITIONS EXPECTED THROUGH FRIDAY.
SGX WATCHES/WARNINGS/ADVISORIES
CA...HIGH WIND WATCH FROM SUNDAY 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 SUNDAY NIGHT THROUGH TUESDAY AFTERNOON
FOR SAN DIEGO COUNTY MOUNTAINS-SAN DIEGO COUNTY VALLEYS.
PZ...NONE.
PUBLIC...SS
AVIATION/MARINE...MUNYAN
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