383
FXUS66 KSGX 171814
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
1014 AM PST MON FEB 17 2025
SYNOPSIS
COOLING WILL SPREAD INLAND TODAY AND TUESDAY AS THE MARINE LAYER
RETURNS AND DEEPENS FOR TONIGHT INTO TUESDAY MORNING. THERE WILL
BE PATCHY LOW CLOUDS AND LOCALLY DENSE FOG NEAR THE COAST EARLY
THIS MORNING WITH MORE WIDESPREAD COASTAL LOW CLOUDS SPREADING
INTO PORTIONS OF THE INLAND VALLEYS FOR LATE TONIGHT INTO TUESDAY
MORNING. THERE WILL BE GUSTY WEST WINDS FOR THE MOUNTAINS AND
DESERTS FOR TODAY AND TONIGHT WITH THE STRONGEST GUSTS ALONG THE
DESERT SLOPES OF THE MOUNTAINS TO 40 TO 50 MPH. SLIGHTLY WARMER ON
WEDNESDAY, SLIGHTLY COOLER ON THURSDAY, THEN A WARMING TREND
THROUGH NEXT WEEKEND WITH SUNDAY HIGH TEMPERATURES AS MUCH AS 10
TO 15 DEGREES ABOVE AVERAGE FOR THE MOUNTAINS AND INLAND VALLEYS.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
UPDATE: THE WEAK COASTAL EDDY IS CONTINUING TO DISSIPATE AND
CLEARING OF HIGHER CLOUDS HAVE BOTH HELPED TO ALLOW THE LOWER DECKS
TO SCATTER OUT. LOOKING AT THE LATEST SATELLITE IMAGERY, THERE STILL
APPEARS TO BE SOME CLOUDS HANGING OFF THE COAST OF POINT LOMA AND
STRETCHING UP TO THE COAST OF SOUTHERN ORANGE COUNTY. THESE CLOUDS
SHOULD REMAIN OVER WATERS FOR THE MOST PART THROUGHOUT THE DAY,
ALTHOUGH THERE COULD BE OCCASIONAL BROKEN TO OVERCAST SKIES RIGHT
ALONG THE IMMEDIATE COAST FOR PORTIONS OF SAN DIEGO COUNTY.
LATEST HIGH RES GUIDANCE KEEPS THE FORMATION OF ANOTHER STRONGER
EDDY TONIGHT, WHICH WILL ALLOW FOR THE RETURN OF THE MARINE LAYER
FOR TONIGHT, AND THICKENING, WITH SOME FOG AND LIGHT DRIZZLE BEING
POSSIBLE, ESPECIALLY FOR THE INLAND VALLEYS. SOME OF THESE LOW
CLOUDS WILL ALSO PUSH INTO PORTIONS OF THE INLAND EMPIRE INTO
EARLY TOMORROW MORNING. IT IS LIKELY WITH A STRONGER COASTAL EDDY
TOMORROW THAT LOW LEVEL CLOUDS WILL TAKE LONGER TO MIX OUT. WEAK
OFF SHORE FLOW, WITH GRADUAL WARMING AND DRYING CONDITIONS, LOOKS
TO OCCUR BEGINNING WEDNESDAY.
DETERMINISTIC MODELS ARE STILL IN RELATIVELY CLOSE AGREEMENT WITH
THE PROPAGATION OF A MAJOR SHORTWAVE TROUGH BY LATER IN THE WEEK,
WHICH WILL ALLOW FOR INCREASING OFF SHORE WINDS IN ITS WAKE. IN
ADDITION, THE FURTHER BUILDING OF THE RIDGE AND STRENGTHENING OF
THE SURFACE HIGH OVER THE WESTERN STATES WILL LEAD TO WARMER AND
DRIER CONDITIONS FOR THIS UPCOMING WEEKEND, WITH TEMPERATURES WELL
ABOVE THE SEASONAL AVERAGE FOR THIS TIME OF YEAR.
PREVIOUS DISCUSSION (SUBMITTED AT 240 AM):
SHORT TERM (TODAY THROUGH WEDNESDAY)
A LOW PRESSURE SYSTEM MOVING INLAND THROUGH THE PACIFIC NORTHWEST
AND NORTHERN CALIFORNIA WILL STRENGTHEN ONSHORE FLOW ACROSS
SOUTHERN CALIFORNIA THROUGH TONIGHT. A WEAK COASTAL EDDY WILL BRING
A RETURN OF PATCHY LOW CLOUDS AND LOCALLY DENSE FOG NEAR THE
COAST EARLY THIS MORNING.
THE COASTAL EDDY WILL BRING MORE RAPID DEEPENING OF THE MARINE
FOR TONIGHT INTO TUESDAY MORNING WITH MORE WIDESPREAD COASTAL LOW
CLOUDS SPREADING INTO PORTIONS OF THE INLAND VALLEYS FOR LATE
TONIGHT INTO TUESDAY MORNING. FOR TUESDAY NIGHT INTO WEDNESDAY
MORNING, THE MARINE LAYER WILL BEGIN TO DECREASE IN DEPTH AND THE
COVERAGE OF LOW CLOUDS WILL BECOME PATCHIER, MAINLY COVERING
PORTIONS OF THE SAN DIEGO COUNTY COASTAL WATERS, SAN DIEGO COUNTY
COASTAL AREAS, AND PORTIONS OF THE SAN DIEGO COUNTY VALLEYS.
THE STRONGER ONSHORE FLOW WILL BRING GUSTY WEST WINDS TO THE
MOUNTAINS AND DESERTS FOR TODAY INTO TONIGHT WITH GUSTS TO 30 TO
40 MPH. ALONG THE EAST SLOPES OF THE MOUNTAINS AND IN THE
NORTHERN COACHELLA VALLEY BELOW THE SAN GORGONIO PASS, THERE WILL
BE LOCALLY STRONGER GUSTS TO 40 TO 50 MPH.
THE STRONGER ONSHORE FLOW WILL ALSO SPREAD COOLING INLAND FOR
TODAY AND TUESDAY WITH HIGH TEMPERATURES TODAY FOR THE COAST AND
VALLEYS A FEW TO AROUND 5 DEGREES COOLER THAN SUNDAY WITH ANOTHER
FEW TO AROUND 5 DEGREES OF COOLING FOR MANY AREAS ON TUESDAY. THEN
A FEW TO AROUND 5 DEGREES OF WARMING ON WEDNESDAY WITH WEAKER
ONSHORE FLOW AND A DECREASE IN THE DEPTH OF THE MARINE LAYER.
LONG TERM (THURSDAY THROUGH SUNDAY)
A LOW PRESSURE SYSTEM MOVING INLAND ALONG THE WEST COAST ON
WEDNESDAY NIGHT AND THURSDAY WILL BRING BRIEFLY STRONGER ONSHORE
FLOW TO SOUTHERN CALIFORNIA WITH HIGH TEMPERATURES A FEW DEGREES
COOLER ON THURSDAY. THEN WARMER AND DRY FOR FRIDAY THROUGH THE
WEEKEND AS HIGH PRESSURE ALOFT STRENGTHENS ACROSS CALIFORNIA. WITH
THE WARMING, HIGH TEMPERATURES ON SUNDAY WILL BE AS MUCH AS 10 TO
15 DEGREES ABOVE AVERAGE FOR THE MOUNTAINS AND INLAND VALLEYS,
INTO THE UPPER 60S NEAR THE COAST TO THE MID 70S TO LOWER 80S IN
THE VALLEYS AND IN THE LOWER TO MID 80S FOR THE LOWER DESERTS.
AVIATION
171630Z...COAST/VALLEYS...AREAS OF IFR CIGS/VIS ALONG THE IMMEDIATE
COAST TO CHANGE TO VFR BETWEEN 17-19Z AS BASES LIFT. LOW CLOUDS TO
DEVELOP HIGHER BUT EARLIER THIS EVENING AFTER 02Z, PUSHING INLAND
OVERNIGHT. BASES INITIALLY WOULD BE AROUND 1000-1500 FEET MSL,
RISING TO 1500-2000 FEET MSL AS COASTAL EDDY DEVELOPS OVERNIGHT INTO
TUESDAY, SCATTERING OUT 17-19Z SOME VIS REDUCTIONS OVER HIGHER
COASTAL TERRAIN. OTHERWISE, SCT-BKN HIGH CLOUDS TODAY AND TONIGHT.
MOUNTAINS/DESERTS...WESTERLY WINDS AFTER 21Z THROUGH TONIGHT, WITH
SURFACE GUSTS 25-45 KTS, STRONGEST OVER THE RIDGES, DESERT SLOPES,
AND THE HIGH DESERT. MODERATE UP/DOWNDRAFTS POSSIBLE IN LEE OF
RIDGES. PATCHY BLDU REDUCING VIS IN THE DESERT. SCT-BKN HIGH CLOUDS
TODAY AND TONIGHT.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE ANTICIPATED THROUGH FRIDAY.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...NONE.
UPDATE...STEWEY
PUBLIC...17
AVIATION/MARINE...CSP/WESTERINK
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