246
FXUS66 KSGX 080419
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
919 PM PDT TUE APR 7 2026
SYNOPSIS
WARM AGAIN WEDNESDAY WITH TEMPERATURES ABOUT 10 DEGREES ABOVE
AVERAGE INLAND, FOLLOWED BY A COOLING TREND THROUGH SUNDAY, WITH
HIGH TEMPERATURES AS MUCH AS 10 TO 15 DEGREES BELOW AVERAGE FOR
THE HIGHER MOUNTAINS AND PORTIONS OF THE INLAND VALLEYS. INCREASING
CHANCES OF SHOWERS LATE FRIDAY THROUGH SATURDAY ALONG WITH A
CHANCE OF THUNDERSTORMS ON SATURDAY. CHANCES FOR ADDITIONAL
SHOWERS CONTINUE INTO LATE SUNDAY. PERIODS OF GUSTY SOUTHWEST TO
WEST WINDS FOR THE MOUNTAINS AND DESERTS ON THURSDAY AND FRIDAY
AND AGAIN ON SUNDAY. THEN DRIER WITH A WARMING TREND FOR EARLY
NEXT WEEK.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
EVENING UPDATE...
LOW CLOUDS HAVE BEGUN TO FORM OFF THE COAST THIS EVENING WITH
CLEAR SKIES ELSEWHERE. THE 00Z KNKX SOUNDING SHOWS THE MARINE
INVERSION BASED NEAR 1500 FT MSL, WHICH IS LOWER THAN THE NEAR
2400 FT THIS MORNING. THE WEAK UPPER LEVEL RIDGE THAT WAS OVERHEAD
BREAKS DOWN TONIGHT, WHILE AT THE SURFACE STRONGER NORTHWEST FLOW
NEAR POINT CONCEPTION WILL DRIVE A COASTAL EDDY OVER THE BIGHT.
THIS WILL HELP DEEPEN THE MARINE LAYER AGAIN, SPREADING LOW CLOUDS
INTO THE COASTAL AREAS AND FAR WESTERN VALLEYS BY WEDNESDAY
MORNING. ONE MORE WARM AND SUNNY DAY ON WEDNESDAY WITH HIGHS
AROUND 10 DEGREES ABOVE NORMAL INLAND, AND AROUND 5 DEGREES ABOVE
NORMAL NEAR THE COAST.
PREVIOUS DISCUSSION...
A COOLING TREND WILL BEGIN ON THURSDAY AND ONSHORE FLOW WILL START
TO STRENGTHEN AS A COLD AND VIGOROUS LOW PRESSURE SYSTEM APPROACHES
FROM THE NORTHWEST. HIGH TEMPERATURES ON THURSDAY WILL MOSTLY BE
A FEW DEGREES LOWER THAN ON WEDNESDAY. HIGH TEMPERATURES ON
THURSDAY WILL RANGE FROM AROUND 70 NEAR THE COAST TO THE MID 70S
TO LOWER 80S FOR THE VALLEYS WITH THE LOWER DESERTS IN THE LOWER
TO MID 90S. THE STRONGER ONSHORE FLOW WILL DRIVE LOW CLOUDS
FARTHER INLAND AS THE MARINE LAYER DEEPENS, POTENTIALLY ALL THE
WAY TO THE COASTAL MTN SLOPES.
THE LOW PRESSURE SYSTEM WILL BRING INCREASING CHANCES FOR SHOWERS
LATE FRIDAY THROUGH SATURDAY ALONG WITH A SLIGHT CHANCE OF
THUNDERSTORMS ON SATURDAY. A REINFORCING SHORTWAVE EMBEDDED IN
THE MEAN NORTHWEST FLOW ALONG THE WEST COAST COULD BRING
ADDITIONAL SHOWERS THROUGH SUNDAY OR SUNDAY NIGHT BUT WITH GREATER
SPREAD IN THE MODEL SOLUTIONS AND RESULTING FORECAST DETAILS.
THROUGH SATURDAY NIGHT, CHANCES FOR MEASURABLE PRECIPITATION RANGE
FROM AROUND 65 PERCENT TOWARD THE COAST TO 80 PERCENT IN THE
MOUNTAIN WITH CHANCES FOR ONE INCH OR MORE OF RAINFALL IN THE
MOUNTAINS AROUND 30 PERCENT AND FOR ONE-HALF INCH OR MORE FOR
COASTAL AREAS AROUND 20 PERCENT. THE SNOW LEVEL WILL LOWER TO
AROUND 6500 FEET LATE SATURDAY AND 6000 FEET ON SUNDAY.
DRY AND WARMER WEATHER IS EXPECTED FOR EARLY NEXT WEEK EVEN THOUGH
WE WILL REMAIN UNDER THE INFLUENCE OF BROAD TROUGHING ALOFT.
AVIATION
080400Z...VFR CONDITIONS CURRENTLY DOMINATE ALL COASTAL AND INLAND
TAF SITES. LOW CLOUDS 1000-1500 FEET MSL CURRENTLY DEVELOPING
OFFSHORE WILL MOVE INTO COASTAL AREAS AFTER 06Z, MOVING ABOUT 15
MILES OF INLAND OVERNIGHT INTO WEDNESDAY. CLOUDS WILL BE SOMEWHAT
PATCHY, AND INTERMITTENT SCATTER OUTS CAN BE EXPECTED OVERNIGHT.
CLOUDS SCATTER OUT 15-17Z FROM EAST TO WEST. CLOUDS 1200-1700 FT MSL
REDEVELOP AFTER 09/06Z.
OTHERWISE, BRISK WEST TO SOUTHWESTERLY WINDS PICK UP OVER THE
MTNS/DESERT FOOTHILLS INTO THE DESERTS AFTER 19Z INTO THE EVENING,
GUSTING TO 20-35 KTS.
MARINE
THERE WILL BE OCCASIONAL WIND GUSTS EXCEEDING 20 KNOTS IN THE OUTER
COASTAL WATERS VICINITY SAN CLEMENTE ISLAND WEDNESDAY NIGHT INTO
EARLY THURSDAY MORNING. THERE IS A 15% CHANCE OF THUNDERSTORMS OVER
THE WATERS FRIDAY NIGHT THROUGH SATURDAY AFTERNOON. OTHERWISE, NO
HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH SATURDAY.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...NONE.
PUBLIC...SS
AVIATION/MARINE...CSP
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