An upper-level ridge built into California beginning May 27th, bringing another warming trend to interior central California. Fresno warmed to 99 degrees on the 27th, and reached 102 the next day.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS HNX wrote it up.
An upper-level ridge built into California beginning May 27th, bringing another warming trend to interior central California. Fresno warmed to 99 degrees on the 27th, and reached 102 the next day. A weak low off Baja California spun mid-level moisture into California from the south, and the combination of heat and moisture triggered strong thunderstorms over the Southern Sierra Nevada and the Tehachapi Mountains each afternoon and evening, beginning on May 27th and continuing through the end of the month. Hail up to 1.5 inch in diameter fell near the town of Orange Cove on the evening of the 28th, and as thunderstorms over the Sierra Nevada, and over San Luis Obispo County, collapsed, outflow winds pushed across the San Joaquin Valley, triggering thunderstorms over the eastern and central Valley. Two of the storms merged into a strong system that produced gusty winds that toppled numerous trees on the Valley floor, as well as 1-inch hail near Visalia. Strong winds also triggered a gust-front tornado (gustnado) that damaged a mobile home park in Orosi.
Convection was weaker on May 29th, as thunderstorms developed earlier and several of the storms were pushed north of the region by a more southeasterly flow aloft. However, this southeast flow also carried thunderstorms from northeastern Los Angeles and northwestern San Bernardino Counties into southeastern Kern County near Rosamond, Edwards AFB, and Boron. One thunderstorm collapsed as it passed west of Edwards AFB in the early afternoon, generating outflow winds that were measured at a peak of 62 knots (71 mph).
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 Hanford, CA wrote its last area forecast discussion before the first event at May 27, 2:05 PM PST, 1 hour 25 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA 305 PM PDT WED MAY 27 2009 .DISCUSSION... SCATTERED SHOWERS AND THUNDERSTORMS DEVELOP EARLY IN THE AFTERNOON OVER THE SIERRA AND KERN COUNTY MOUNTAINS AND DESERT. CONVECTIVE DEBRI CLOUDS FROM THE STORMS AND EAST FLOW MAY PROVIDE MOSTLY CLOUDY SKIES OVER MUCH OF THE REGION DURING THE EVENING. OVERNIGHT LOWS SHOULD BE A BIT WARMER THAN LAST NIGHT WITH 24 HOUR TRENDS RUNNING SEVERAL DEGREES WARMER. MODELS INDICATE LITTLE CHANGE IN THE AIRMASS INTO THE WEEKEND. MOISTURE OVER THE HIGH DESERT WILL REMAIN OVER THE REGION INTO SUNDAY. A WEAK UPPER TROUGH WILL APPROACH THE CHANNEL ISLANDS MAINTAINING A LIGHT ESE FLOW WHICH IS FAVORABLE FOR CONVECTION OVER THE SIERRA. EXPECT LITTLE CHANGE IN TEMPERATURES INTO SUNDAY. MODELS INDICATE A SIGNIFICANT CHANGE IN THE PATTERN TAKING PLACE EARLY NEXT WEEK. A COOLER SW FLOW DEVELOPS MONDAY AS A DEEP UPPER LOW APPROACHES THE NORTH CALIFORNIA COAST. A MUCH COOLER AIRMASS AND STRONG ONSHORE FLOW ON TUESDAY WILL RESULT IN BREEZY CONDITIONS IN THE VALLEY AND WINDY ACROSS THE KERN COUNTY MOUNTAINS AND DESERT. COOL TEMPERATURE COULD REMAIN FOR A COUPLE OF DAYS NEXT WEEKS AS SOME OF THE MODELS PROG THE LOW CLOSING OFF AND SLOWLY MOVE SOUTH INTO SOUTH CALIFORNIA THURSDAY. && .AVIATION...LOCAL MVFR IN SCATTERED SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS BETWEEN 00Z AND 06Z THURSDAY. THUNDERSTORMS REDEVELOPING OVER THE MOUNTAINS AFTER 19Z THURSDAY. OTHERWISE...VFR CONDITIONS WILL PREVAIL ACROSS THE CENTRAL CALIFORNIA INTERIOR THROUGH 00Z FRIDAY. && .AIR QUALITY ISSUES... ON WEDNESDAY MAY 27 2009... UNHEALTHY FOR SENSITIVE GROUPS IN FRESNO... KERN... KINGS... MADERA... MERCED AND TULARE COUNTIES. FURTHER INFORMATION IS AVAILABLE AT VALLEYAIR.ORG && .HNX WATCHES/WARNINGS/ADVISORIES... NONE. && PUBLIC...MV AVN/FW...GREISS WEATHER.GOV/HANFORD
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA 115 PM PDT WED MAY 27 2009 CAZ093>097-272230- MARIPOSA MADERA AND FRESNO COUNTY FOOTHILLS- TULARE COUNTY FOOTHILLS-KERN COUNTY MOUNTAINS- SIERRA NEVADA FROM YOSEMITE TO KINGS CANYON- TULARE COUNTY MOUNTAINS- 115 PM PDT WED MAY 27 2009 ...THUNDERSTORMS OVER THE MOUNTAINS THIS AFTERNOON... ISOLATED THUNDERSTORMS HAVE DEVELOPED OVER THE SOUTHERN SIERRA NEVADA...AND OVER THE TEHACHAPI MOUNTAINS NEAR PINE MOUNTAIN CLUB...THIS AFTERNOON. THE THUNDERSTORMS WERE MOVING WEST AT 5 TO 15 MPH. THUNDERSTORM ACTIVITY WILL BECOME MORE WIDESPREAD WITH AFTERNOON HEATING...AND A FEW STORMS COULD DRIFT OVER THE SIERRA FOOTHILLS. THESE THUNDERSTORMS MAY PRODUCE LOCALLY HEAVY RAIN...SMALL HAIL...GUSTY WINDS AND LIGHTNING. PEOPLE IN THE MOUNTAINS SHOULD MONITOR CONDITIONS AND SEEK SHELTER IF A THUNDERSTORM APPROACHES. REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE AT RISK FROM LIGHTNING. SANGER WEATHER.GOV/HANFORD
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA 325 PM PDT WED MAY 27 2009 CAZ093>097-280230- MARIPOSA MADERA AND FRESNO COUNTY FOOTHILLS- TULARE COUNTY FOOTHILLS-KERN COUNTY MOUNTAINS- SIERRA NEVADA FROM YOSEMITE TO KINGS CANYON- TULARE COUNTY MOUNTAINS- 325 PM PDT WED MAY 27 2009 ...THUNDERSTORMS CONTINUE OVER THE SOUTHERN SIERRA NEVADA... SCATTERED THUNDERSTORMS WILL CONTINUE TO DEVELOP ALONG THE LENGTH OF THE SOUTHERN SIERRA NEVADA...FROM YOSEMITE SOUTH THROUGH THE PIUTES. THE THUNDERSTORMS WERE MOVING WEST AT 5 TO 10 MPH...AND A FEW STORMS COULD DRIFT OVER THE SIERRA FOOTHILLS. SPOTTERS HAVE REPORTED PEA SIZE HAIL AND CLOUD TO GROUND LIGHTNING WITH SOME OF THE THUNDERSTORMS...AND THESE WILL REMAIN THE MAIN THREATS. IN ADDITION...THESE THUNDERSTORMS MAY PRODUCE LOCALLY HEAVY RAIN AND GUSTY WINDS. PEOPLE IN THE SOUTHERN SIERRA NEVADA SHOULD MONITOR CONDITIONS AND SEEK SHELTER IF A THUNDERSTORM APPROACHES. REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE AT RISK FROM LIGHTNING. SANGER WEATHER.GOV/HANFORD
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA 331 PM PDT WED MAY 27 2009 CAZ093>097-280230- MARIPOSA MADERA AND FRESNO COUNTY FOOTHILLS- TULARE COUNTY FOOTHILLS-KERN COUNTY MOUNTAINS- SIERRA NEVADA FROM YOSEMITE TO KINGS CANYON- TULARE COUNTY MOUNTAINS- 331 PM PDT WED MAY 27 2009 ...THUNDERSTORMS CONTINUE OVER THE SOUTHERN SIERRA NEVADA... SCATTERED THUNDERSTORMS WILL CONTINUE TO DEVELOP ALONG THE LENGTH OF THE SOUTHERN SIERRA NEVADA...FROM YOSEMITE SOUTH THROUGH THE PIUTES. THE THUNDERSTORMS WERE MOVING WEST AT 5 TO 10 MPH...AND A FEW STORMS COULD DRIFT OVER THE SIERRA FOOTHILLS. SPOTTERS HAVE REPORTED PEA SIZE HAIL AND CLOUD TO GROUND LIGHTNING WITH SOME OF THE THUNDERSTORMS...AND THESE WILL REMAIN THE MAIN THREATS. IN ADDITION...THESE THUNDERSTORMS MAY PRODUCE LOCALLY HEAVY RAIN AND GUSTY WINDS. PEOPLE IN THE SOUTHERN SIERRA NEVADA SHOULD MONITOR CONDITIONS AND SEEK SHELTER IF A THUNDERSTORM APPROACHES. REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE AT RISK FROM LIGHTNING. SANGER WEATHER.GOV/HANFORD
The San Joaquin Valley radar (KHNX), 106 km away, was scanning. The volume nearest the first event began at 23:29 UTC.
13 thunderstorm wind, 6 hail, 1 flash flood. Local standard time, as filed.
A trained SKYWARN spotter reported 1 inch of rain in only 45 minutes in Coarsegold. Several mudslides reported on SR 41 near Coarsegold.
A trained SKYWARN weather spotter reported numerous windshields broken in the Coarsegold area and along SR 41 near the Chukchansi Report.
Local broadcast media reported Nickel size hail near Coarsegold.
A spotter reported penny sized hail in Yosemite National Park.
A spotter at Yosemite Lakes reported penny size hail.
Law enforcement in Porterville reported a roof blown off a barn due to outflow winds from a severe thunderstorm.
NWS Employee reported trees down and near zero visibility in blowing dust along SR 198 just east of Visalia.
NWS officials toured damage around the town of Orosi in Tulare County. Extensive wind damage from thunderstorm outflow in the town was evident. Several homes exhibited minor roof damage. Fences and trees were damaged or downed. Property damages were estimated. NWS concluded that a gust front tornado, commonly called a gustnado, occurred in this location, based on damage pattern as well as patterns indicated in tall dry grass and tree trunks and tops, and eyewitness accounts. Gust front tornadoes can occur in the outflow of a severe thunderstorm and are not considered to be true tornadoes. Winds were estimated at 60 mph.
A trained NWS spotter reported ping pong ball sized hail (1.5 inches in diameter) 6 miles east of Orange Cove. The large hail caused broken windows, roof damage, dented metal and damaged windshields on cars.
A trained spotter reported quarter sized hail on the west side of Visalia.
A three foot diameter tree was downed by severe thunderstorm winds.
County officials reported a large tree downed onto a house from severe thunderstorm winds.
NWS Employee reported 2 large trees downed in Hidden Valley Park in Hanford.
Officials reported a large tree downed in Reedley due to severe thunderstorm winds.
The public reported three tree trunks sheared. One tree fell on a canopy. The other two trees were sheared about 5 feet above the ground.
NWS Employee reported several power poles knocked down by high thunderstorm winds on the west side of Lemoore.
A large tree was downed due to severe thunderstorm winds at the corner of Lincoln and Orange Streets in Fresno.
Emergency Management reported a large tree downed in the town of Sanger.
County government reported a large tree downed in Riverdale.
Outflow winds from a severe thunderstorm. Report relayed by NASA employees.
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: 176502, 176498, 176499, 185391, 195505, 185387, 185392, 185389, 176500, 176501, 185388, 185390, 195512, 195507, 195511, 195515, 195508, 195509, 195510, 195506.