122
FXUS66 KSGX 010348
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
848 PM PDT MON MAR 31 2025
SYNOPSIS
COOL WEATHER WITH LIGHT PRECIPITATION AT TIMES THROUGH THURSDAY,
WITH THE HIGHEST CHANCES AND MOST WIDESPREAD PRECIPITATION ON
THURSDAY. GUSTY WINDS CONTINUE THROUGH TUESDAY NIGHT IN THE
MOUNTAINS AND DESERTS WITH GUSTS 45 TO 55 MPH, ISOLATED TO 70 MPH.
COASTAL AREAS WILL BE WINDY TUESDAY AFTERNOON AND NIGHT AS WELL.
DRIER WARMER WEATHER WILL RETURN BY THE WEEKEND AND CONTINUE INTO
EARLY NEXT WEEK.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
A WEAK SHORT WAVE MOVING THROUGH CA AND AMPLE LOW-LEVEL MOISTURE
ARE ALLOWING AREAS OF LIGHT PRECIPITATION TO CONTINUE THIS
EVENING, MAINLY ACROSS SAN DIEGO COUNTY. FOR THE MOST PART,
PRECIPITATION TOTALS HAVE BEEN LESS THAN 0.20" IN THE COASTAL
AREAS AND VALLEYS, LOCALLY AROUND 0.25-0.60" ACROSS THE FOOTHILLS
AND MOUNTAINS, HIGHEST AT MOUNT LAGUNA AND LYTLE CREEK.
THE UPPER LEVEL TROUGH ALONG THE WEST COAST AMPLIFIES AND BROADENS
INTO THURSDAY WITH ADDITIONAL SHORT WAVES MOVING THROUGH THE MEAN
FLOW AND INTO SO CAL. THIS WILL MAINTAIN COOL AND BREEZY WEATHER
WITH PERIODS OF LIGHT PRECIPITATION THROUGH MUCH OF THE WEEK.
MID-LEVEL WINDS INCREASE AS THE TROUGH DIGS SOUTHWARD ON TUESDAY,
BRINGING MORE WIDESPREAD GUSTY WESTERLY WINDS, INCLUDING TO THE
COASTAL AREAS AND VALLEYS TUESDAY AFTERNOON THROUGH TUESDAY NIGHT.
A PAIR OF SHORT-WAVES MOVES THROUGH TUESDAY NIGHT, BRINGING
ADDITIONAL LIGHT SHOWERS TO THE VALLEYS AND MOUNTAINS WHERE THERE
IS A 20-50% CHANCE OF PRECIPITATION. FOR TUESDAY EVENING THROUGH
WEDNESDAY MORNING, THERE IS A 10-20% CHANCE OF AT LEAST 0.10" OF
RAIN, AND A 20-35% CHANCE IN THE MOUNTAINS, HIGHEST ON THE WEST
FACING COASTAL SLOPES. SNOW LEVELS WILL BE MUCH LOWER DURING THIS
PERIOD, FALLING FROM AROUND 5000 FT TUESDAY EVENING TO 3500-4000
FT WEDNESDAY MORNING WITH LESS THAN AN INCH OF ACCUMULATION. DRIER
NORTHWEST FLOW FOLLOWS DURING THE DAY WEDNESDAY, BRINGING A BRIEF
BREAK IN THE PRECIPITATION. BREEZY ONSHORE FLOW WILL CONTINUE ON
WEDNESDAY, THOUGH WEAKER, ALONG WITH COOL WEATHER ACROSS THE
REGION.
THE FINAL SHORT WAVE DROPS DOWN THE BACK SIDE OF THE TROUGH ON
THURSDAY, CAUSING IT TO AMPLIFY. WITH MINIMAL TRAJECTORY OVER THE
PACIFIC, THIS SYSTEM REMAINS RELATIVELY MOISTURE-STARVED. STILL,
THERE SHOULD BE ENOUGH MOISTURE AND CERTAINLY ENOUGH INSTABILITY
FOR ANOTHER ROUND OF SHOWERS THURSDAY INTO FRIDAY MORNING. NBM
PROBABILITIES OF 0.10" OR MORE ARE AROUND 5-15% FOR THE COASTAL
AREAS AND VALLEYS AND 15-40% FOR THE MOUNTAINS, HIGHEST ON THE
WEST FACING COASTAL SLOPES. UPPER LEVEL WINDS AND PRESSURE
GRADIENTS FINALLY RELAX FOR WEAKER ONSHORE WINDS ON THURSDAY. THE
TROUGH SHIFTS SLIGHTLY EASTWARD ON FRIDAY, BRINGING AN END TO THE
PRECIPITATION AND SOME WARMING. THE TROUGH REMAINS SOMEWHERE IN
THE VICINITY SATURDAY, ALTHOUGH ENSEMBLES VARY GREATLY WITH THE
PLACEMENT, WHICH WILL INFLUENCE HOW MUCH WARMING WE WILL SEE AND
THE POTENTIAL DEVELOPMENT OF ANY OFFSHORE FLOW, ESPECIALLY AS WE
HEAD INTO SUNDAY.
AVIATION
010300Z...COAST/VALLEYS/FOOTHILLS...SOME -RA/DZ WILL BE POSSIBLE,
ESPECIALLY FOR THE INLAND AREAS, THROUGHOUT THE EVENING HOURS. LOW
CLOUDS ASSOCIATED WITH PRECIPITATION ARE DOWN TO 500-1000FT MSL,
OTHERWISE CIGS IN SD COUNTY AND ORANGE COUNTY ARE CONTINUING TO RISE
TO 1500-2000FT. CONDITIONS WILL CONTINUE TO GRADUALLY IMPROVE INTO
THE OVERNIGHT HOURS NORTHWEST TO SOUTHEAST, WITH BASES EVENTUALLY
SCATTERING OUT FOR MOST LOCATIONS AFTER 09Z, WITH THE EXCEPTION OF
SOME OF THE COASTAL AREAS. ELEVATED ONSHORE FLOW PICKS UP AFTER 15Z
WITH GUSTS TO 20-25 KTS POSSIBLE INTO THE AFTERNOON. CLOUDS WILL
REGATHER AND FILL BACK IN TOMORROW EVENING AFTER 06Z WEDNESDAY,
MORESO FOR SAN DIEGO COUNTY AND THE SOUTHERN PORTION OF ORANGE
COUNTY. THESE BASES WILL REMAIN AROUND 1000-1500FT MSL, AND THEN
BEGIN TO LIFT AFTER 12Z WEDNESDAY TO 2000-3000FT MSL.
HIGHER MOUNTAINS/DESERTS...SCT CLOUDS AOA 15000 FEET MSL TONIGHT AND
TOMORROW. WESTERLY WINDS WILL INCREASE AGAIN TOMORROW. GUSTS 30-50
KTS OVER THE RIDGES AND IN WIND-PRONE MOUNTAIN PASSES, WITH GUSTS 25-
35 KTS WITHIN THE OPEN DESERTS. AREAS OF MODERATE UP/DOWNDRAFTS,
INCLUDING LOCALIZED LLWS AND ROTORS, IN LEE OF MOUNTAINS AND
MOUNTAIN PASSES, ARE EXPECTED.
MARINE
CALMER SEAS AND WINDS OVER THE WATERS TONIGHT, BUT HAZARDOUS
CONDITIONS TO RETURN TOMORROW. A SHORT PERIOD (7-8 SECONDS)
NORTHWEST SWELL (290-300 DEGREES) ARRIVES EARLY TUESDAY, BRINGING
VERY STEEP AND CHOPPY SEAS TO 10-13 FEET. WINDS INCREASE
SUBSTANTIALLY AS WELL, GUSTING TO 30-35 KNOTS IN THE OUTER WATERS
AND TO 25-30 KTS FOR THE NEARSHORE WATERS. WINDS PEAK TUESDAY NIGHT
INTO WEDNESDAY MORNING. WINDS AND SEAS SLOWLY FALL ON THURSDAY. A
SMALL CRAFT ADVISORY REMAINS IN EFFECT TONIGHT THROUGH EARLY
WEDNESDAY MORNING WITH A GALE WARNING NOW IN EFFECT FOR THE OUTER
WATERS ON TUESDAY/TUESDAY AFTERNOON. SEE THOSE PRODUCTS FOR MORE
DETAILS.
BEACHES
ELEVATED SURF OF 3-6 FEET THROUGH TONIGHT, WITH ASSOCIATED MODERATE
TO HIGH RIP CURRENT RISKS POSSIBLE. HIGHER SURF DEVELOPS TUESDAY AND
WEDNESDAY TO 5-7 FEET AND SETS TO 8 FEET ON WEST-FACING BEACHES.
OCCASIONAL SETS NEAR 9-10 FT POSSIBLE ON WEST FACING BEACHES IN THE
OVERNIGHT HOURS TUESDAY INTO WEDNESDAY A HIGH RIP CURRENT RISK WILL
EXIST FOR ALL BEACHES FOR BOTH DAYS.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...WIND ADVISORY FROM NOON TUESDAY TO 2 AM PDT WEDNESDAY FOR ORANGE
COUNTY COASTAL AREAS-ORANGE COUNTY INLAND AREAS-SAN
BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE-
SAN DIEGO COUNTY COASTAL AREAS-SAN DIEGO COUNTY VALLEYS-
SANTA ANA MOUNTAINS AND FOOTHILLS.
WIND ADVISORY UNTIL 2 AM PDT WEDNESDAY FOR APPLE AND LUCERNE
VALLEYS-COACHELLA VALLEY-RIVERSIDE COUNTY MOUNTAINS-SAN
BERNARDINO COUNTY MOUNTAINS-SAN DIEGO COUNTY DESERTS-SAN
DIEGO COUNTY MOUNTAINS-SAN GORGONIO PASS NEAR BANNING.
PZ...SMALL CRAFT ADVISORY FROM 2 AM TUESDAY TO 9 AM PDT WEDNESDAY FOR
COASTAL WATERS FROM SAN MATEO POINT TO THE MEXICAN BORDER
AND OUT TO 10 NM.
SMALL CRAFT ADVISORY UNTIL 3 PM PDT TUESDAY FOR WATERS FROM SAN
MATEO POINT TO THE MEXICAN BORDER EXTENDING 10 TO 60 NM OUT
INCLUDING SAN CLEMENTE ISLAND.
SMALL CRAFT ADVISORY FROM 9 AM TO 11 PM PDT WEDNESDAY FOR WATERS
FROM SAN MATEO POINT TO THE MEXICAN BORDER EXTENDING 10 TO
60 NM OUT INCLUDING SAN CLEMENTE ISLAND.
GALE WARNING FROM 3 PM TUESDAY TO 9 AM PDT WEDNESDAY FOR WATERS
FROM SAN MATEO POINT TO THE MEXICAN BORDER EXTENDING 10 TO
60 NM OUT INCLUDING SAN CLEMENTE ISLAND.
PUBLIC...SS
AVIATION/MARINE/BEACHES...STEWEY
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