A severe thunderstorm was reported in San Luis Obispo county near the community of LaPanza. Three quarter inch hail was reported by the local fire station.
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The episode as NWS LOX wrote it up.
A severe thunderstorm was reported in San Luis Obispo county near the community of LaPanza. Three quarter inch hail was reported by the local fire station.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Los Angeles, CA wrote its last area forecast discussion before the first event at May 28, 1:00 PM PST, 1 hour 45 minutes earlier.
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA 200 PM PDT THU MAY 28 2009 .SHORT TERM (TONIGHT THROUGH SUNDAY)...LATEST SATELLITE/RADAR SHOWS CONVECTIVE ACTIVITY AS EXPECTED OVER THE MOUNTAIN AREAS AND INTERIOR VALLEYS...WITH MOST ACTIVITY OVER SLO/SBA/VTU COUNTIES. TSTMS WILL LIKELY PRODUCE SMALL HAIL...HEAVY RAIN AND GUSTY WINDS. ALSO...NOT OUT OF THE REALM OF POSSIBILITY TO GET AN ISOLATED DRY STRIKE AWAY FROM THE MAIN THUNDERSTORM. PARAMETERS ARE RIPE FOR SEVERE AND/OR FLASH FLOODING WARNINGS...SO RADAR WILL BE MONITORED CLOSELY THROUGH THE AFTERNOON. FORECAST WISE...12Z MODELS ARE ON THE SAME PAGE. AT UPPER LEVELS RIDGE OVER THE SOUTHWEST STATES WILL BE PUSHED EASTWARD THROUGH THE PERIOD AS A WEAK TROUGH MOVES INLAND OVER THE AREA. NEAR THE SURFACE...ONSHORE FLOW IS FORECAST TO CONTINUE THROUGH SUNDAY. FOR FRIDAY...MID-LEVEL FLOW TURNS SOUTHERLY...SO WILL EXPECT A DECREASE IN CONVECTIVE ACTIVITY OVER THE HIGHER TERRAIN. STILL SHOULD BE ENOUGH MOISTURE AND INSTABILITY TO WARRANT SLIGHT CHANCE POPS FOR SBA/VTU/LAX MOUNTAINS AND PARTS OF THE CUYAMA VALLEY. BY SATURDAY WITH THE TROUGH MOVING OVERHEAD...CONVECTIVE THREAT WILL BE NIL. OTHERWISE...EXPECT CONTINUED DEEP MARINE LAYER FOR THE AREA WITH STRATUS REACHING INTO THE SANTA CLARITA VALLEY EACH NIGHT/MORNING THROUGH SUNDAY. AS FOR TEMPS...EXPECT ONLY MINOR FLUCTUATIONS THROUGH SUNDAY WITH HIGHS HOVERING AROUND SEASONAL NORMS. .LONG TERM (MONDAY THROUGH THURSDAY)...FOR THE EXTENDED...MODELS SEEM TO BE IN GENERAL AGREEMENT THROUGH THE PERIOD WITH THE MAIN FOCUS ON A DEVELOPING UPPER LOW. THIS UPPER LOW DEVELOPS OVER THE EASTERN PACIFIC...AND DROPS IT SOUTHEAST TO A COUPLE HUNDRED MILES WEST OF THE CENTRAL COAST BY WEDNESDAY/THURSDAY. AT THIS TIME...DIFFICULT TO DETERMINE EXACTLY HOW MUCH MOISTURE THE SOUTH TO SOUTHWEST FLOW AROUND THIS SYSTEM WILL HAVE TO WORK WITH. SO...AT THIS TIME...WILL NOT INTRODUCE ANY MENTIONABLE POPS INTO THE FORECAST. HOWEVER...DEPENDING ON FUTURE MODEL RUNS...POPS MAY HAVE TO BE ADDED TO THE FORECAST. NO MATTER WHAT HAPPENS WITH THE RAIN CHANCES...THIS SCENARIO WILL RESULT IN COOLER TEMPS FOR ALL AREAS THROUGH THE PERIOD...AND PARTLY TO MOSTLY CLOUDY SKIES. && .AVIATION...28/1825Z. MOST COASTAL TAF SITES ARE ON THE VERGE OF CLEARING WITH A FAIRLY QUICK RETURN OF LOW CLOUDS AND FOG EXPECTED AGAIN EARLY THIS EVENING. COASTAL SITES WILL EXPERIENCE MVFR CONDITIONS...LOCAL IFR CONDITIONS ON THE CENTRAL COAST...TONIGHT WHILE THE VALLEY TAFS WILL EXPERIENCE MVFR TO LOCAL IFR CONDITIONS LATER TONIGHT. ANOTHER AREA OF CONCERN IS THE ANTELOPE VALLEY THIS AFTERNOON WHERE THERE IS A SLIGHT CHANCE OF AFTERNOON CONVECTION AND VCTS HAS BEEN INCLUDED IN THE TAFS. KLAX...GOOD CONFIDENCE IN CLEARING AROUND 19 TO 20Z FOLLOWED BY MOSTLY VFR CONDITIONS THIS AFTERNOON ASIDE FROM AN AFTERNOON INTRUSION BY THE LOW CLOUDS ALONG WITH THE SEA BREEZE CAUSING MVFR CEILINGS. BY EARLY THIS EVENING THE LOW CLOUDS AND FOG ARE BACK TO STAY WITH MVFR CONDITIONS LASTING THROUGH THE NIGHT AND THROUGH MOST OF FRIDAY MORNING. KBUR...GOOD CONFIDENCE IN VFR CONDITIONS THROUGH LATE THIS EVENING WHEN THE LOW CLOUDS AND FOG RETURN AND CAUSE MVFR TO LOCAL IFR CONDITIONS FOR THE REST OF THE NIGHT AND THROUGH MID MORNING FRIDAY. && .LOX WATCHES/WARNINGS/ADVISORIES... NONE && PUBLIC...THOMPSON AVIATION...SWEET WWW.WEATHER.GOV/LOSANGELES
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA 600 AM PDT THU MAY 28 2009 CAZ034>041-044>046-051>054-059-087-088-547-548-291300- SAN LUIS OBISPO COUNTY CENTRAL COAST- SANTA BARBARA COUNTY CENTRAL COAST-SANTA YNEZ VALLEY- SAN LUIS OBISPO COUNTY INTERIOR VALLEYS-CUYAMA VALLEY- SANTA BARBARA COUNTY SOUTH COAST-VENTURA COUNTY COAST- LOS ANGELES COUNTY COAST INCLUDING DOWNTOWN LOS ANGELES- VENTURA COUNTY INTERIOR VALLEYS-VENTURA COUNTY COASTAL VALLEYS- SANTA MONICA MOUNTAINS RECREATIONAL AREA- SAN LUIS OBISPO COUNTY MOUNTAINS- SANTA BARBARA COUNTY MOUNTAINS-VENTURA COUNTY MOUNTAINS- LOS ANGELES COUNTY MOUNTAINS EXCLUDING THE SANTA MONICA RANGE- ANTELOPE VALLEY-CATALINA ISLAND-SANTA CLARITA VALLEY- LOS ANGELES COUNTY SAN FERNANDO VALLEY- LOS ANGELES COUNTY SAN GABRIEL VALLEY- 600 AM PDT THU MAY 28 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHWESTERN CALIFORNIA. .DAY ONE... TODAY AND TONIGHT THERE IS A SLIGHT CHANCE OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS MAINLY OVER THE MOUNTAINS AND DESERT. THE MAIN THREAT WITH THUNDERSTORMS WILL BE GUSTY WINDS AND POSSIBLE DRY LIGHTNING. LITTLE RAINFALL...IF ANY...IS EXPECTED. .DAYS TWO THROUGH SEVEN... FRIDAY THROUGH WEDNESDAY THERE IS A SLIGHT CHANCE OF THUNDERSTORMS MAINLY OVER THE MOUNTAINS AND DESERT ON FRIDAY. THE MAIN THREAT WITH THESE POSSIBLE STORMS WILL BE GUSTY WINDS AND POSSIBLE DRY LIGHTNING. LITTLE RAINFALL...IF ANY...IS EXPECTED. HALL
The national radar mosaic for the moment the first event began.
1 hail. Local standard time, as filed.
The Cal Fire station in LaPanza reported a thunderstorm produced three quarter inch hail.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2009Every state in 2009This day in weather historyWarnings in California, May 2009
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 169370.