An upper-level disturbance off the west coast of Baja California spun a fetch of subtropical moisture into California beginning July 16th, with isolated thunderstorms developing along the Southern Sierra Nevada crest. By the 18th, there was enough moisture that thunderstorms also formed in the Kern County deserts, with one afternoon thunderstorm near Edwards AFB reaching severe criteria with…
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 disturbance off the west coast of Baja California spun a fetch of subtropical moisture into California beginning July 16th, with isolated thunderstorms developing along the Southern Sierra Nevada crest. By the 18th, there was enough moisture that thunderstorms also formed in the Kern County deserts, with one afternoon thunderstorm near Edwards AFB reaching severe criteria with gusts to 67 mph. Thunderstorms over the Sierra and the Kern desert redeveloped the next day, and spread into the Tehachapi Mountains. Around an inch of rain fell in the Frazier Park-Pine Mountain Club area, but no flooding was reported.
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 Jul 18, 1:50 PM PST, 1 hour 35 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA 250 PM PDT SAT JUL 18 2009 .DISCUSSION...A FEW THUNDERSTORMS HAVE DEVELOPED OVER THE THE SIERRA DUE TO DIURNAL HEATING AND MONSOON MOISTURE. STORM STEERING FLOW FROM THE SOUTH HAS KEPT THE STORMS ALONG AND EAST OF THE SIERRA CREST. THIS STORM ACTIVITY SHOULD DIMINISH DURING THE EARLY EVENING WITH THE LOSS OF DAY TIME HEATING. ADDITIONAL MID TO UPPER LEVEL MOISTURE FROM REMNANTS OF A TROPICAL STORM WILL MOVE OVER CENTRAL CALIFORNIA TONIGHT. SATELLITE PICTURES DO NOT INDICATE ANY DISTURBANCES TO INITIATE CONVECTION. HOWEVER THE MOISTURE SHOULD HELP MAINTAIN WARM TEMPERATURES OVERNIGHT. MODELS PROG PLENTY OF MID LEVEL MOISTURE OVER THE AREA SUNDAY AND MONDAY. THUS CONVECTIVE STORM THREAT SHOULD CONTINUE OVER THE MOUNTAINS. THE STRONG RIDGE OVER THE FOUR CORNERS AREA WILL BE NUDGE SOUTHWARD BY UPPER TROUGH MOVING EAST ALONG PAC NW AND CANADIAN BORDER. TEMPERATURES MAY BE A DEGREE OR TWO COOLER INTO MIDWEEK BUT STILL REMAIN IN THE TRIPLE DIGITS. WARMER TEMPERATURES WILL BE POSSIBLE TOWARDS THE END OF THE WEEK PERHAPS BY THURSDAY AS THE RIDGE AMPLIFIES NORTHWARD. SOUTH FLOW AROUND THE RIDGE WILL BRING A SURGE OF MONSOON MOISTURES INTO SOUTH CALIFORNIA. INCREASING THE THREAT FOR THUNDERSTORMS OVER THE MOUNTAINS AND DESERT THURSDAY AND INTO THE WEEKEND. && .AVIATION...ISOLATED THUNDERSTORMS ARE POSSIBLE OVER THE SOUTHERN SIERRA NEVADA AND TEHACHAPI MOUNTAINS AND THE KERN DESERTS BETWEEN 19Z TODAY AND 03Z SUNDAY. OTHERWISE...VFR CONDITIONS WILL PREVAIL ACROSS THE CENTRAL CALIFORNIA INTERIOR THROUGH 18Z SUNDAY. && .AIR QUALITY ISSUES... ON SATURDAY JULY 18 2009... UNHEALTHY IN FRESNO... KERN AND TULARE COUNTIES. UNHEALTHY FOR SENSITIVE GROUPS IN KINGS COUNTY. FURTHER INFORMATION IS AVAILABLE AT VALLEYAIR.ORG && .HNX WATCHES/WARNINGS/ADVISORIES... NONE. && PUBLIC...MV AVN/FW...DS WEATHER.GOV/HANFORD
The national radar mosaic for the moment the first event began.
2 thunderstorm wind, 1 heavy rain. Local standard time, as filed.
The NASA wind sensor at the South Lake Bed near Edwards AFB reported severe wind gusts from the outflow of a thunderstorm.
The NASA wind sensor at the Mid Lake Bed reported severe wind gusts from the outflow of a thunderstorm.
A trained weather spotter at Pine Mountain Club reported heavy rainfall of about one inch.
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, July 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: 191717, 191718, 191716.