989
FXUS66 KSGX 172050
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
150 PM PDT SAT MAY 17 2025
SYNOPSIS
COOL AND CLOUDY CONDITIONS WITH GUSTY WEST
WINDS TODAY. MARINE LAYER THICKENS, BRINGING CHANCES OF LIGHT RAIN
AND DRIZZLE WEST OF THE MOUNTAINS INTO SUNDAY MORNING. AS THE TROUGH
MOVES EAST, A RIDGE DEVELOPS INTO NEXT WEEK, QUICKLY WARMING
TEMPERATURES AND RENDERING A SHALLOWER MARINE LAYER. PERIODS OF
LOCALLY GUSTY OFFSHORE WINDS ARE EXPECTED MONDAY MORNING THROUGH
MONDAY AFTERNOON.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
THIS AFTERNOON...AN UPPER LEVEL TROUGH FROM THE GULF OF ALASKA WILL
CONTINUE TO DIG THROUGH THE GREAT BASIN THIS AFTERNOON, REACHING ITS
MAXIMUM SOUTHERN EXTENT BY TONIGHT AROUND THE CALIFORNIA/ARIZONA
BORDER, PUSHING SLOWLY EASTWARD THROUGHOUT SUNDAY, THEN BREAKING
DOWN MONDAY AS THE UPPER LEVEL FLOW BECOMES MORE ZONAL. WIND GUSTS
OF 35-45 MPH ARE BEING OBSERVED IN THE HIGH DESERTS. STRONGEST WINDS
WILL BE OBSERVED THIS EVENING THROUGHOUT SOUTHERN CALIFORNIA WITH
GUSTS OF 45-55 MPH IN THE MOUNTAINS AND DESERTS AND LOCALLY UP TO 65
MPH IN THE WINDIEST LOCATIONS. AREAS OF BLOWING DUST ARE POSSIBLE IN
THE DESERTS, REDUCING VISIBILITY AT TIMES.
TONIGHT, THE MARINE LAYER WILL BECOME THICK ENOUGH TO RING OUT
INTERMITTENT LIGHT RAIN THROUGH EARLY SUNDAY MORNING, ESPECIALLY FOR
SAN DIEGO COUNTY AREAS BELOW 5000 FEET. TOTAL RAINFALL SHOULD AMOUNT
TO NO MORE THAN 0.10 INCHES.
DRY WITH A WARMING TREND BEGINNING ON SUNDAY AS LOW PRESSURE MOVES
EASTWARD INTO THE ROCKIES AND WEAK HIGH PRESSURE BUILDS OVER THE
WEST COAST. A SURFACE HIGH MOVING INTO THE GREAT BASIN WILL BRING
PERIODS OF WEAK OFFSHORE FLOW ON MONDAY, WITH LOCALLY GUSTY
NORTHEAST TO EAST WINDS. CURRENT GUIDANCE SHOWS THE OFFSHORE WINDS
PEAKING LATE MONDAY MORNING WITH LOCAL WIND GUSTS OF 35 TO 40 MPH ON
THE COASTAL SLOPES OF THE SAN BERNARDINO MTNS, IN THE NORTHERN PARTS
OF THE IE AND IN THE SANTA ANA MTNS. THE OFFSHORE WINDS WILL WEAKEN
ON MONDAY EVENING. WEAK OFFSHORE WINDS WILL ALSO BE OBSERVED TUESDAY
MORNING.
UNDER HIGH PRESSURE ALOFT, TEMPERATURES WILL CONTINUE TO RISE
THROUGH MIDWEEK AND WED AND THU ARE LIKELY TO BE THE WARMEST DAYS
WITH DAYTIME HIGH TEMPS REACHING THE MID TO UPPER 90S IN THE IE ON
BOTH THOSE DAYS. 45-55% CHANCE OF EXCEEDING 100F IN THE IE WED AND
THU. THE MARINE LAYER WILL MAINTAIN LESS OF A PRESENCE WITH DAY-TO-
DAY VARIATIONS ON THE AMOUNT OF LOW CLOUDS/FOG DURING THE NIGHTS AND
MORNINGS BUT DAYTIME TEMPERATURES WILL REACH THE MID 70S NEAR THE
COAST.
TEMPERATURES WILL AGAIN TREND LOWER FOR NEXT WEEKEND AS A LOW
PRESSURE TROUGH APPROACHES FROM THE NORTHWEST BUT THERE ISN'T MUCH
CONFIDENCE IN THE DETAILS OF THE FORECAST DUE TO THE SPREAD AMONG
MODEL SOLUTIONS.
AVIATION
172030Z...COAST/VALLEYS...BKN-OVC CLOUDS REMAIN IN PLACE ACROSS THE
COASTAL BASIN THIS AFTERNOON WITH MORE SCT-BKN FOR PORTIONS OF THE
EASTERN VALLEYS. BASES HAVE LIFTED GENERALLY OVER 3000FT MSL THIS
AFTERNOON, BUT SHOULD SETTLE BACK DOWN CLOSER TO 2500-3500FT
OVERNIGHT. MORE SCATTERED LIGHT SHOWERS/DRIZZLE POSSIBLE AFTER 00Z
SUNDAY, CONTINUING THROUGH ABOUT 18Z SUNDAY. CLOUDS GRADUALLY
CLEARING LATE SUNDAY MORNING INTO SUNDAY AFTERNOON FROM NORTHWEST TO
SOUTHEAST, WITH NEARLY FULL CLEARING BY LATE SUNDAY AFTERNOON.
MOUNTAINS/DESERTS...SCT HIGH CLOUDS PREVAIL. WEST TO SOUTHWEST GUSTS
35-55KTS OVER THE DESERT FOOTHILLS AND THROUGH PASSES THIS
AFTERNOON/EVENING, GRADUALLY WANING TONIGHT. STRONG UP/DOWNDRAFTS IN
THE LEE OF MOUNTAINS SUCH AS NEAR KPSP EXPECTED AND BLDU LIKELY
THROUGH 08Z SUNDAY, PRIMARILY IN THE DESERTS AND COACHELLA VALLEY,
WHERE VIS MAY FALL BELOW 3SM AT TIMES. WIDESPREAD GUSTS 25-35KTS
PICK BACK UP SUNDAY AFTERNOON.
MARINE
ONSHORE WINDS GUSTING NEAR 20KTS NEAR SAN CLEMENTE ISLAND LATE THIS
AFTERNOON INTO EARLY SUNDAY MAY LEAD TO SOME CHOPPY SEAS IN THE
OUTER WATERS. OTHERWISE, NO HAZARDOUS MARINE CONDITIONS EXPECTED
THROUGH THURSDAY.
BEACHES
ELEVATED SURF WILL IMPACT BEACHES SUNDAY AND EARLY MONDAY, PEAKING
SUNDAY AFTERNOON/EVENING. EXPECTED SURF OF 3-5 FEET WITH SETS TO 6
FEET PRODUCING A HIGH RIP CURRENT RISK.
SGX WATCHES/WARNINGS/ADVISORIES
CA...WIND ADVISORY UNTIL 2 AM PDT SUNDAY FOR APPLE AND LUCERNE
VALLEYS-RIVERSIDE COUNTY MOUNTAINS-SAN BERNARDINO COUNTY
MOUNTAINS-SAN DIEGO COUNTY DESERTS-SAN DIEGO COUNTY
MOUNTAINS-SAN GORGONIO PASS NEAR BANNING.
PZ...NONE.
PUBLIC...WESTERINK
AVIATION/MARINE/BEACHES...MUNYAN
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