600
FXUS66 KSGX 012056
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
156 PM PDT TUE APR 1 2025
SYNOPSIS
AN EXTENSIVE LOW PRESSURE SYSTEM OVER THE WESTERN STATES WILL MAINTAIN
COOLER CONDITIONS INTO THURSDAY ALONG WITH OCCASIONAL SHOWERS AND
A SLIGHT CHANCE OF THUNDERSTORMS WEDNESDAY AND AGAIN THURSDAY
AFTERNOON. THERE WILL ALSO BE PERIODS OF STRONGER AND GUSTY WEST
WINDS THROUGH TONIGHT WITH GUSTS 45 TO 55 MPH IN THE MOUNTAINS AND
DESERTS. DRY AND WARMER FOR THE WEEKEND INTO NEXT WEEK WITH HIGH
TEMPERATURES RISING TO AROUND AVERAGE FOR THE WEEKEND AND ABOVE
AVERAGE FOR THE MIDDLE OF NEXT WEEK.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
THIS AFTERNOON...A FEW LIGHT SHOWERS CONTINUE, MAINLY OVER THE SAN
DIEGO COUNTY VALLEYS AND COASTAL AREAS. A FEW LIGHT SHOWERS HAVE
ALSO DEVELOPED OVER THE RIVERSIDE COUNTY MOUNTAINS. SFC PRESSURE
GRADIENTS REMAIN STRONGLY ONSHORE, SUPPORTING WIND GUSTS OF 45-55
MPH IN THE WIND-FAVORED LOCATIONS OF THE MTNS AND ADJACENT
DESERTS.
FROM PREVIOUS DISCUSSION...
WINDS ARE BEGINNING TO STRENGTHEN IN THE LOWER ELEVATIONS WEST OF
THE MTNS THIS AFTERNOON WITH GUSTS OF 30 TO 40 MPH NEAR THE COAST
AND 25 TO 35 MPH IN THE INLAND EMPIRE. HIGH TEMPERATURES TODAY
WILL BE SEVERAL DEGREES LOWER THAN YESTERDAY AS COLDER AIR
CONTINUES TO FILTER IN FROM THE NORTHWEST. ISOLATED, MOSTLY LIGHT
SHOWERS WILL CONTINUE OVER AND WEST OF THE MOUNTAINS THIS
AFTERNOON, WITH ADDITIONAL RAINFALL IN THE MOUNTAINS OF A FEW
HUNDERDTHS TO ONE-THIRD INCH AND SNOWFALL OF AROUND ONE INCH
ABOVE 7000 FEET.
A REINFORCING SHORTWAVE EMBEDDED IN THE NORTHWEST FLOW ON THE BACK
SIDE OF THE MEAN TROUGH WILL MOVE THROUGH CA TONIGHT AND WEDNESDAY,
BRINGING ANOTHER ROUND OF SHOWERS WITH THE SNOW LEVEL FALLING TO
3000 TO 4000 FEET LATE TONIGHT AND RISING TO AROUND 4500 FEET FOR
WEDNESDAY AFTERNOON. ADDITIONAL RAINFALL AND LIQUID-EQUIVALENT
ABOVE THE SNOW LEVEL IS EXPECTED TO RANGE FROM ONE-TENTH INCH OR
LESS NEAR THE COAST TO ONE-QUARTER TO ONE-HALF INCH IN THE
MOUNTAINS WITH LOCALLY GREATER AMOUNTS. SNOWFALL OF 3 TO 5 INCHES
IS POSSIBLE, MOSTLY ABOVE 5000 TO 5500 FEET. THERE WILL ALSO BE A
SLIGHT CHANCE OF THUNDERSTORMS WEDNESDAY MORNING.
A SECOND IMPULSE WILL BRING ANOTHER INCREASE IN SHOWER ACTIVITY
WEDNESDAY NIGHT INTO THURSDAY EVENING WITH MORE COLD AIR BRINGING
THE SNOW LEVEL DOWN TO 4000-4500 FEET FOR WEDNESDAY NIGHT. THE
SNOW LEVEL WILL RISE AGAIN TO 5000-5500 FEET FOR THURSDAY
AFTERNOON AND EVENING. ADDITIONAL RAINFALL AND LIQUID-EQUIVALENT
ABOVE THE SNOW LEVEL IS EXPECTED TO RANGE FROM ONE-TENTH INCH OR
LESS NEAR THE COAST TO TO AROUND ONE-QUARTER INCH IN THE MOUNTAINS
WITH LOCALLY GREATER AMOUNTS. SNOWFALL OF 3 TO 5 INCHES IS
POSSIBLE, MOSTLY ABOVE 5000 TO 5500 FEET WITH LOCALLY 5 TO 9
INCHES ON THE HIGHER PEAKS ABOVE 7500 FEET. THERE IS ALSO A SLIGHT
CHANCE OF THUNDERSTORMS FOR THURSDAY AFTERNOON.
THE DOMINANT LOW PRESSURE TROUGH OVER THE WESTERN STATES WILL BEGIN TO
MOVE EAST INTO THE PLAINS AND WEAKEN FOR FRIDAY AND SATURDAY. A
TRANSIENT HIGH PRESSURE RIDGE ALOFT WILL MOVE OVER CALIFORNIA FROM
THE WEST ON SUNDAY WITH A WEAK LOW PRESSURE SYSTEM MOVING QUICKLY
INLAND NORTH OF POINT CONCEPTION AROUND MONDAY. THERE WILL BE
WARMING FOR FRIDAY THROUGH SUNDAY, WITH HIGH TEMPERATURES RISING TO
AROUND AVERAGE OVER THE WEEKEND. THE LOW PRESSURE SYSTEM MOVING
INLAND THROUGH NORTHERN AND CENTRAL CALIFORNIA AROUND MONDAY WILL
BRING STRONGER ONSHORE FLOW TO SOUTHERN CALIFORNIA WITH SLIGHT
COOLING AND GUSTY WEST WINDS FOR THE MOUNTAINS AND DESERTS.
AVIATION
012030Z...COAST/VALLEYS/COASTAL MOUNTAIN SLOPES...SCT TO
OCCASIONALLY BKN CUMULUS FIELD PRESENT THIS AFTERNOON WITH BASES
GENERALLY 3000-4000FT MSL. NORTHWEST WIND GUSTS TO 20-25 KTS WILL
CONTINUE ACROSS THE COASTS AND VALLEYS THIS AFTERNOON, GRADUALLY
WEAKENING AFTER 00Z THIS EVENING. LOW CLOUDS BASED AT 2500-3500 FEET
MSL WILL INCREASE AFTER 02Z, MAINLY IN SAN DIEGO COUNTY. BASES
LIKELY LIFT ABOVE 3000FT MSL AFTER 10Z WEDNESDAY MORNING.
DESERT MOUNTAIN SLOPES/DESERTS...SCT-BKN CLOUDS AOA 15000 FEET MSL.
AREAS OF HIGH DESERT BKN CLOUDS 4000 FEET MSL. WESTERLY WINDS WITH
GUSTS 35-55 KTS OVER THE RIDGES AND IN WIND-PRONE MOUNTAIN PASSES,
AND GUSTS 25-35 KTS WITHIN THE OPEN DESERTS CONTINUE THROUGH THIS
EVENING. AREAS OF MODERATE UP/DOWNDRAFTS, INCLUDING LOCALIZED LLWS
AND ROTORS, IN LEE OF MOUNTAINS (I.E., VCNTY KPSP). GUSTS BEGIN TO
WANE SOME AFTER 06Z WEDNESDAY, BUT LOOK TO REMAIN ELEVATED THROUGH
WEDNESDAY AFTERNOON.
MARINE
STRONG WESTERLY WINDS HAVE PICKED UP THIS AFTERNOON WITH 25-30 KTS
ALREADY OBSERVED. WAVE HEIGHTS WILL CONTINUE TO INCREASE AS WELL,
WITH VERY STEEP SEAS CONTINUING INTO WEDNESDAY. GALES PICK UP IN THE
OUTER WATERS THIS AFTERNOON AS WELL. WINDS AND SEAS DIMINISH SOME ON
WEDNESDAY BUT HAZARDOUS CONDITIONS PERSIST THROUGH WEDNESDAY EVENING
IN THE OUTER WATERS. SEE THE GALE WARNING AND THE SMALL CRAFT
ADVISORY FOR DETAILS.
BEACHES
WHILE A 9-10FT 300 DEGREE NORTHWESTERLY SWELL APPROACHES LATER
TODAY, THE FAIRLY SHORT PERIOD OF 8-9 SECONDS KEEPS MAXIMUM WAVE
HEIGHTS TO AROUND 8-10 FEET. GIVEN THE NORTHWESTERLY DIRECTION, ONLY
WEST-NORTHWEST FACING BEACHES WILL FEEL THE EFFECTS OF THIS SWELL
AND ISLAND SHADOWING WILL LIKELY PLAY A ROLE IN LIMITING THE
OCCURRENCE OF TRUE 9-10FT WAVES. STILL, STRONG RIP CURRENTS ARE
EXPECTED ALONG ALL BEACHES THROUGH WEDNESDAY. SURF OF 3-6 FEET
EXPECTED ALONG ORANGE COUNTY BEACHES, AND LARGELY 4-7 FEET IN SAN
DIEGO COUNTY BEACHES BUT THE TRUE WNW FACING BEACHES COULD SEE SETS
TO 9 FEET. A HIGH SURF ADVISORY HAS BEEN ISSUED FOR THIS AFTERNOON
THROUGH NOON WEDNESDAY, WITH THE HIGHEST WAVES EXPECTED BETWEEN
MIDNIGHT TONIGHT AND 6 AM WEDNESDAY. SURF DIMINISHES BY NOON
WEDNESDAY.
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 WEDNESDAY FOR APPLE AND LUCERNE
VALLEYS-COACHELLA VALLEY-ORANGE COUNTY COASTAL AREAS-ORANGE
COUNTY INLAND AREAS-RIVERSIDE COUNTY MOUNTAINS-SAN
BERNARDINO COUNTY MOUNTAINS-SAN BERNARDINO AND RIVERSIDE
COUNTY VALLEYS-THE INLAND EMPIRE-SAN DIEGO COUNTY COASTAL
AREAS-SAN DIEGO COUNTY DESERTS-SAN DIEGO COUNTY MOUNTAINS-
SAN DIEGO COUNTY VALLEYS-SAN GORGONIO PASS NEAR BANNING-
SANTA ANA MOUNTAINS AND FOOTHILLS.
HIGH SURF ADVISORY UNTIL NOON PDT WEDNESDAY FOR SAN DIEGO COUNTY
COASTAL AREAS.
PZ...SMALL CRAFT ADVISORY UNTIL 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 THIS AFTERNOON 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 UNTIL 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...PG
AVIATION/MARINE/BEACHES...MUNYAN
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