652
FXUS66 KSGX 171627
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
927 AM PDT SAT MAY 17 2025
SYNOPSIS
COOL AND CLOUDY CONDITIONS WITH INCREASINGLY 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 MORNING...A CLOSED UPPER LOW MOVING EAST THROUGH NORTHWESTERN
MEXICO HAS DEEPENED OUR MARINE LAYER. PATCHY DRIZZLE HAS BEEN
OBSERVED ALONG THE FOOTHILLS OF SAN DIEGO COUNTY AND THE INLAND
EMPIRE, ACCUMULATING A FEW HUNDREDTHS OF AN INCH. THIS SHORTWAVE
GETS ABSORBED INTO THE MAIN TROUGH, WHICH DIGS IN FROM THE GULF OF
ALASKA TODAY, REACHING ITS MAXIMUM SOUTHERN EXTENT BY TONIGHT
INTO THE GREAT BASIN. THIS INSIDE SLIDER SIGNATURE WILL YIELD
STRONG WESTERLY WINDS THIS AFTERNOON THROUGH EARLY SUNDAY MORNING,
PEAKING THIS EVENING 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. LATER THIS AFTERNOON, 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 AN MTNS. THE OFFSHORE WINDS WILL WEAKEN
ON MONDAY EVENING.
UNDER THE WEAK 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. 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
171630Z...COAST/VALLEYS...LOW CLOUDS REMAIN IN PLACE THROUGH THE
COASTAL MOUNTAIN FOOTHILLS THIS MORNING, AND WHILE PORTIONS OF THE
INLAND VALLEYS MAY SEE PARTIAL CLEARING INTO THE AFTERNOON, THE
COASTS LOOK TO STAY BKN-OVC THROUGH THE AFTERNOON. BASES HAVE LIFTED
TO 2500-3500FT MSL AND SHOULD REMAIN AROUND THIS LEVEL THROUGH
TONIGHT. MORE SCATTERED LIGHT SHOWERS/DRIZZLE POSSIBLE AFTER 00Z
SUNDAY, CONTINUING THROUGH ABOUT 18Z SUNDAY.
MOUNTAINS/DESERTS...SCT HIGH CLOUDS PREVAIL. WEST TO SOUTHWEST GUSTS
25-40KTS OVER THE DESERT FOOTHILLS AND THROUGH PASSES WILL BECOME
MORE WIDESPREAD THROUGH THE DESERTS AND STRENGTHEN TO 35-55KTS IN
THE NEXT HOUR OR SO, PRODUCING STRONG UP/DOWNDRAFTS IN THE LEE OF
MOUNTAINS SUCH AS VCNTY KPSP. BLDU LIKELY 20Z SATURDAY THROUGH 08Z
SUNDAY, PRIMARILY IN THE DESERTS AND COACHELLA VALLEY, WHERE VIS MAY
FALL BELOW 3SM AT TIMES.
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 WEDNESDAY.
BEACHES
ELEVATED SURF WILL IMPACT BEACHES SUNDAY AND EARLY MONDAY. EXPECTED
SURF OF 4-6 FEET WOULD PRODUCE A HIGH RIP CURRENT RISK.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
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/PG
AVIATION/MARINE/BEACHES...MUNYAN/ZUBER
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