827
FXUS66 KSGX 161812
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
1112 AM PDT SAT MAY 16 2026
SYNOPSIS
COOLER FOR THIS WEEKEND, ESPECIALLY FOR INLAND AREAS WITH
STRONGER ONSHORE FLOW. THE MARINE LAYER WILL DEEPEN DURING THE
WEEKEND WITH NIGHT AND MORNING COASTAL LOW CLOUDS EXTENDING WELL
INLAND AND ONTO THE COASTAL SLOPES OF THE MOUNTAINS. FOR SATURDAY
AFTERNOON INTO SUNDAY EVENING, SOUTHWEST TO WEST WINDS FOR THE
MOUNTAINS AND DESERTS WILL GUST TO 40 TO 50 MPH, WITH ISOLATED
GUSTS TO 65 MPH. THE COAST AND VALLEYS WILL WARM ON MONDAY WITH
THE GREATER WARMING FOR INLAND AREAS FOR TUESDAY THROUGH
WEDNESDAY, FOLLOWED BY A SLIGHT COOLDOWN FROM THURSDAY INTO
FRIDAY.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
TODAY THROUGH TOMORROW NIGHT...
AN "INSIDE SLIDER" TYPE MAJOR SHORTWAVE TROUGH IS GOING TO DEEPEN
AND PROPAGATE OVER THE DESERT SOUTHWEST, WHICH WILL RESULT IN A
TIGHTENING OF THE SURFACE GRADIENT AND ALLOW FOR WINDS TO BECOME
RATHER STRONG AND GUSTY OVER THE HIGHER TERRAIN, AND THROUGH THE
MOUNTAIN CANYONS, WHERE WINDS WILL BE SUSTAINED UP AROUND 40 TO 50
MPH BY LATER THIS AFTERNOON FOR WIND-PRONED AREAS. THERE COULD ALSO
BE SOME ISOLATED GUSTS APPROACHING 65 TO 70 MPH FOR THE WINDIEST
AREAS. THERE COULD BE SOME AREAS OF BLOWING DUST, AND ESPECIALLY
WITHIN THE COACHELLA VALLEY. FOR THE HIGH DESERTS, AS MIN RH VALUES
DROP INTO THE LOW TEENS BY LATER THIS AFTERNOON, WITH STRONG AND
GUSTY WINDS, CONDITIONS WILL BE FAVORABLE FOR FIRE GROWTH AND
SPREAD, ALTHOUGH FUELS ARE NOT YET CRITICAL FOR THESE AREAS. ONSHORE
FLOW WILL ALSO BECOME MORE ENHANCED, LEADING TO A MORE PERSISTENT
MARINE LAYER, WHICH WILL LIKELY REMAIN RATHER PREVALENT FOR THE
COASTAL AREAS. TEMPERATURES WILL ALSO BE ON THE COOLER SIDE WITH
SOME REINFORCEMENT OF COLDER AIR BEHIND THIS TROUGH AS IT PASSES
OVER THE REGION, WITH HIGHS BEING SLIGHTLY BELOW THE SEASONAL
AVERAGE FOR THIS TIME OF YEAR, ESPECIALLY FOR THE INLAND VALLEYS,
WHERE HIGHS WILL BE AS MUCH AS 10 DEGREES BELOW AVERAGE FOR SOME
LOCATIONS. GIVEN THE TRACK OF THIS SYSTEM, IT SHOULD REMAIN DRY,
ONLY PERHAPS A FEW AREAS OF DRIZZLE WILL BE POSSIBLE AGAINST THE
COASTAL SLOPES, OTHERWISE JUST COOLER AND MORE BREEZY THROUGHOUT THE
WEEKEND.
MONDAY THROUGH FRIDAY...
AFTER PASSAGE OF THE TROUGH MOVING THROUGH THIS WEEKEND, HIGH
PRESSURE IS GOING TO BUILD BACK IN BEHIND IT, WITH DIMINISHING WINDS
SWITCHING TO A WEAK OFFSHORE FLOW ALOFT RETURNING THROUGH THE EARLY
PART OF THE WEEK. THIS WILL RESULT IN GRADUAL WARMING THROUGH
WEDNESDAY BEFORE THE LONGWAVE PATTERN BECOMES MORE ZONAL WITH ONLY
WEAK RIDGING ALOFT GOING INTO THE LATTER HALF OF THE WEEK. THIS WILL
GIVE WAY TO THE APPEARANCE OF THE MORE COMMON "MAY GREY" DIURNAL
PATTERN, WITH BETTER COVERAGE AT THE COAST THROUGHOUT THE DAY, AND
TEMPERATURES SLOWLY COOLING OFF FROM THURSDAY INTO FRIDAY. DRY
CONDITIONS LOOK TO ALSO PERSIST THROUGH NEXT WEEK.
AVIATION
161800Z...COAST/VALLEYS...LOW CLOUDS ARE BEGINNING TO BREAK UP ALONG
THE COAST THOUGH SOUTHERN SAN DIEGO COUNTY LOOKS TO REMAIN UNDER LOW
CLOUD COVER FOR MOST OF THE PERIOD. LOW CLOUD BASES ARE EXPECTED TO
REMAIN BETWEEN 2000-4000FT MSL WITH A FEW CLOUDS MOVING IN AND OUT
AOA 1500FT MSL. LOW CLOUDS WILL INCREASE IN COVERAGE AFTER 23Z
BEGINNING IN SD COUNTY, STRETCHING NORTH AND FILLING INLAND VALLEYS
AFTER 00Z. LOW CLOUDS ARE EXPECTED TO REACH COASTAL OC AFTER 06-08Z.
MINOR VIS REDUCTIONS (3-5SM) EXPECTED FOR SOME ELEVATED INLAND
VALLEYS, WITH LOWER VIS WHERE CLOUDS INTERSECT TERRAIN.
MOUNTAINS/DESERTS...WINDS HAVE BEEN GUSTY OUT OF THE NORTH TO
NORTHWEST AND WILL CONTINUE THROUGH THIS EVENING. GUSTS HAVE ALREADY
REACHED 25-35 KNOTS IN DESERT SLOPES AND MOUNTAIN PASSES, LOCALLY UP
TO 50 KNOTS. MOD UP/DOWNDRAFTS AND LOCAL LLWS IN LEE OF MOUNTAINS.
WINDS WILL CONTINUE TO STRENGTHEN INTO THE AFTERNOON WITH WIDESPREAD
GUSTS 35-45 KNOTS, LOCALLY TO 60 KTS IN WIND PRONE LOCATIONS. WINDS
WILL REMAIN GUSTY THROUGH SUNDAY. STRONG UP/DOWNDRAFTS IN LEE OF
MTNS WITH BLDU AND REDUCED VIS EXPECTED. OTHERWISE, SKC AND VFR
EXPECTED THROUGH THE PERIOD.
MARINE
GUSTY WESTERLY WINDS WITH GUSTS 20-30 KT WILL DEVELOP IN THE OUTER
COASTAL WATERS LATE THIS AFTERNOON. THE STRONGEST GUSTS WILL OCCUR
NEAR SAN CLEMENTE ISLAND. SEAS OF 7-10 FEET WITH A 9-12 SECOND
PERIOD WILL GENERATE CHOPPY SEAS. WINDS AND SEAS WILL SLOWLY
DIMINISH THROUGH THE DAY SUNDAY. A SMALL CRAFT ADVISORY IS IN EFFECT
AND CONTAINS MORE INFORMATION.
BEACHES
A WESTERLY SWELL FROM 290 DEGREES WITH A 9 TO 10 SECOND PERIOD WILL
BRING ELEVATED SURF OF 4 TO 6 FEET, SETS TO 7 FEET THIS AFTERNOON
THROUGH MONDAY MORNING. HIGHEST SURF AT WEST TO NORTHWEST FACING
BEACHES. THE COMBINATION OF ELEVATED SURF AND HIGH TIDES OF 6.5 TO 7
FEET WILL RESULT IN MINOR TIDAL OVERFLOW, ESPECIALLY FOR BEACH
PARKING LOTS AND BOARDWALKS. SURF WILL START TO DECREASE MONDAY
AFTERNOON. A BEACH HAZARDS STATEMENT IS IN EFFECT AND CONTAINS MORE
INFORMATION.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...BEACH HAZARDS STATEMENT FROM 6 PM PDT THIS EVENING THROUGH
MONDAY MORNING FOR ORANGE COUNTY COASTAL AREAS-SAN DIEGO
COUNTY COASTAL AREAS.
WIND ADVISORY UNTIL 11 PM PDT SUNDAY FOR APPLE AND LUCERNE
VALLEYS-SAN BERNARDINO COUNTY MOUNTAINS-SAN GORGONIO PASS
NEAR BANNING.
WIND ADVISORY UNTIL 11 PM PDT SUNDAY FOR RIVERSIDE COUNTY
MOUNTAINS-SAN DIEGO COUNTY DESERTS-SAN DIEGO COUNTY
MOUNTAINS.
PZ...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 7 AM PDT SUNDAY
FOR WATERS FROM SAN MATEO POINT TO THE MEXICAN BORDER
EXTENDING 10 TO 60 NM OUT INCLUDING SAN CLEMENTE ISLAND.
PUBLIC...STEWEY
AVIATION/MARINE...VILLAFANE
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