Thunderstorms occurred over the central Sierra during the afternoon of July 29th.
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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 REV wrote it up.
Thunderstorms occurred over the central Sierra during the afternoon of July 29th.
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 Reno, NV wrote its last area forecast discussion before the first event at Jul 29, 5:15 AM PST, 6 hours 55 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RENO NV 615 AM PDT WED JUL 29 2009 .UPDATE... ISOLATED CONVECTIVE CELLS DEVELOPING FROM VICINITY PYRAMID LAKE TO THE SOUTHEAST WHERE WEAK MID LVL VORT LOBE IS POSITIONED. ATMOS IS FAIRLY UNSTABLE EARLY THIS MORNING. LIKELY THAT CELLS WILL DEVELOP OVER A LARGER AREA MUCH EARLIER THAN YESTERDAY. ANOTHER ROUND OF UPDATES IS ON THE WAY. MLF && .PREVIOUS DISCUSSION... /ISSUED 458 AM PDT WED JUL 29 2009/ UPDATE... DEFORMATION AXIS CURRENTLY EXTENDS OVER MONO COUNTY NORTHEAST INTO SOUTHERN PORTIONS OF MINERAL. WHILE IT DOES NOT APPEAR THAT SHOWERS ARE REACHING THE GROUND IN MINERAL COUNTY...THINK AS MORNING PROGRESSES THAT INSTABILITY WILL INCREASE RATHER QUICKLY AND CONVECTIVE DEVELOPMENT WILL EXTEND EAST INTO MINERAL AND SOUTHERN LYON COUNTIES BEFORE 18 UTC. THUS HAVE OPTED TO UPDATE CURRENT FORECAST TO ACCOUNT FOR EARLIER START TO CONVECTION IN THAT PART OF THE CWA. OTHERWISE NO CHANGES. MLF PREVIOUS DISCUSSION... /ISSUED 254 AM PDT WED JUL 29 2009/ SHORT TERM... SHOWERS HAVE MAINLY ENDED OVERNIGHT HOWEVER WEAK DEFORMATION ALONG THE PASSING UPPER VORT MAX IS CONTINUING TO CAUSE LIGHT RADAR RETURNS OVER MONO COUNTY AT THIS HOUR. MOISTURE AND INSTABILITY INCREASES TODAY BRINGING BETTER CHANCES AND COVERAGE FOR THUNDERSTORMS. CONVECTIVE INITIATION WILL OCCUR EARLIER TODAY WITH INITIAL DEVELOPMENT OVER THE SOUTHERN SIERRA BY LATE THIS MORNING. WEAK DEFORMATION BETWEEN A VORT OVER THE SRN SIERRA AND ANOTHER OVER NRN CA MAY ENHANCE CONVECTION ALONG THE SIERRA THIS AFTERNOON. LIGHT WESTERLY AFTERNOON WINDS WILL SPREAD THE STORMS OVER THE REMAINING PORTION OF THE CWA BY LATE AFTERNOON. THE STORM CHARACTERISTICS SHOULD BE SIMILAR TO YESTERDAY WITH HEAVY RAIN THE MAIN CONCERN...HOWEVER GREATER INSTABILITY TODAY MAY BRING BETTER HAIL GENERATION AS WELL. MODELS HAVE BACKED OFF ON UPPER FORCING OVERNIGHT SO MOST STORMS ARE EXPECTED TO DISSIPATE BY MIDNIGHT. A DEEP UPPER LOW OVER THE ERN PACIFIC SHIFTS CLOSER TO THE WEST COAST THURSDAY...HOWEVER MOISTURE AND INSTABILITY REMAINS OVER THE REGION. CURRENT PROGS INDICATE SLIGHTLY LESS STORM COVERAGE THAN WEDNESDAY WITH LESS FOCUS ALONG THE SIERRA AND MORE OVER THE GREAT BASIN ZONES. WESTERLY FLOW ALOFT IS SLIGHTLY HIGHER SO STORM MOTION WILL BE A LITTLE FASTER. THE STORMS WILL STILL MAINLY BE WET HOWEVER THE POTENTIAL FOR OUTFLOW WINDS WILL BE HIGHER. THE UPPER LOW MOVES EVEN CLOSER TO THE WEST COAST FRIDAY WITH INCREASING SOUTHWEST FLOW ALOFT WHICH WILL START TO DRY THINGS OUT. MODELS DO INDICATE A BULLSEYE OF INSTABILITY OVER NRN CA FRIDAY IN RESPONSE TO COOLING ALOFT AHEAD OF THE LOW. KEPT WITH HIGHEST POPS OVER THE NRN ZONES FOLLOWING THIS SOLUTION WITH WEST WINDS KICKING IN BY LATE AFTERNOON AND DRYING OUT THE SIERRA ZONES FROM TAHOE NORTH. MODELS HAVE BEEN VERY INCONSISTENT WITH THE TRACK OF THIS LOW SO THIS SOLUTION WILL LIKELY CHANGE. JORDAN LONG TERM...SATURDAY THROUGH TUESDAY... LIMITED CHANGES MADE TO GOING EXTENDED FORECAST THIS CYCLE. WHILE MEDIUM RANGE MODELS HAD COME MORE IN LINE WITH EACH OTHER 24 HOURS AGO...NOW GFS AND ECMWF ARE AGAIN PARTING COMPANY FOR THE LATTER HALF OF THE EXTENDED PERIOD WRT HANDLING OF THE UPPER LOW OFF THE CA COAST. OPERATIONAL GFS IS NOW TRYING TO BRING THIS LOW MUCH CLOSER TO THE COAST WHILE ECMWF CONTINUES ITS TREND OF KEEPING THE LOW WELL OFF SHORE. GFS ENSEMBLE MEMBERS GENERALLY SUPPORT THE OPERATIONAL RUN THIS CYCLE. GIVEN THAT ECMWF HAS BEEN MORE CONSISTENT WITH ITSELF THE LAST FEW DAYS WILL CONTINUE TO LEAN MORE TOWARD ITS FORECAST. LEANING MORE ON THE ECMWF MEANS GOING ABOVE NUMERICAL GUIDANCE FOR HIGH TEMPS THROUGH MOST OF THE EXTENDED FORECAST...ESPECIALLY THE LAST TWO DAYS...AS HEIGHTS FALLS NOTED IN THE GFS WOULD CALL FOR TEMPS BELOW AVERAGE. DEVELOPING SW FLOW IN THE MID AND UPPER LVLS OVER MUCH OF THE CWA SHOULD LEAD TO SOME DRYING AND A REDUCED CHANCE OF CONVECTION. WE STARTED WITH MINIMAL CONVECTIVE CHANCES IN THE FORECAST. AM LESS INCLINED TO REMOVE POPS COMPLETELY THAN TO JUST TRIM THEM BACK A BIT...AND THIS WAS DONE. DID ADD SOME MENTION OF CONVECTION TO FAR NRN ZONES FOR SATURDAY THROUGH MONDAY. IF OPERATIONAL GFS...AND MOST OF ITS ENSEMBLE MEMBERS...ARE MORE CORRECT...OR IF LOW JUST MOVES A BIT CLOSER TO THE COAST...IT IS LIKELY THAT FAR NRN AREAS WOULD BE IN A MORE FAVORABLE AREA IN TERMS OF DYNAMICS FOR THE DEVELOPMENT OF CONVECTION. LATE NIGHT SHOWERS NOT OUT OF THE QUESTION THOSE AREAS EITHER. CONFIDENCE REMAINS QUITE LOW IN THE EXTENDED FORECAST GIVEN LACK OF CONSISTENCY BETWEEN THE MEDIUM RANGE MODELS AND RUN TO RUN INCONSISTENCY OF THE OPERATIONAL GFS. MLF AVIATION... PRIMARILY VFR CONDITIONS EXPECTED THROUGH THURSDAY...HOWEVER CONVECTION WILL DEVELOP AGAIN TODAY WITH BETTER OVERALL COVERAGE... ESPECIALLY THROUGH THE SIERRA AND INTO WRN NV. VSBYS COULD DROP TO AS LOW AS 5 MILES AT KTRK AND KTVL IN TSTMS THIS AFTN. GUSTY SFC WINDS OF UP TO 40 KT ALSO POSSIBLE FOR KTRK/KTVL/KRNO BY LATE AFTN/EARLY EVNG. CONVECTION SHOULD BEGIN AROUND 29/19 UTC ALONG THE SIERRA THEN MOVE INTO WRN NV AFTER 29/21 UTC. WILL MENTION CB FOR KLOL BUT WILL LEAVE MENTION OF VCTS OUT OF THE TAF FOR NOW. MLF && .REV WATCHES/WARNINGS/ADVISORIES... NV...NONE. CA...NONE. && HTTP://WEATHER.GOV/RENO
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RENO NV 455 AM PDT WED JUL 29 2009 CAZ070>073-NVZ001>005-300000- SURPRISE VALLEY CALIFORNIA-LASSEN-EASTERN PLUMAS- EASTERN SIERRA COUNTIES-GREATER LAKE TAHOE AREA-MONO- MINERAL AND SOUTHERN LYON COUNTIES-GREATER RENO-CARSON CITY- MINDEN AREA-WESTERN NEVADA BASIN AND RANGE INCLUDING PYRAMID LAKE- NORTHERN WASHOE COUNTY- 455 AM PDT WED JUL 29 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE EASTERN SIERRA... NORTHEAST CALIFORNIA AND WESTERN NEVADA. .DAY ONE...TODAY AND TONIGHT ISOLATED THUNDERSTORMS WILL DEVELOP LATE THIS MORNING ALONG THE SIERRA. THE THUNDERSTORMS WILL BECOME MORE SCATTERED IN NATURE AND MOVE EAST AND NORTHEAST INTO NORTHEAST CALIFORNIA AND WESTERN NEVADA DURING THE AFTERNOON. BRIEF PERIODS OF MODERATE TO HEAVY RAIN ARE POSSIBLE WITH THE STRONGEST THUNDERSTORMS...ESPECIALLY OVER HIGHER TERRAIN. RAINFALL AMOUNTS OF UP TO ONE INCH ARE POSSIBLE IN THESE DOWN POURS. ADDITIONALLY...SMALL HAIL IS POSSIBLE WITH THE STRONGEST THUNDERSTORMS. THE THUNDERSTORMS WILL DISSIPATE BY LATE IN THE EVENING. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY THUNDERSTORMS WILL DEVELOP AGAIN EACH DAY FROM THURSDAY THROUGH SATURDAY. HOWEVER...THE THUNDERSTORM COVERAGE WILL DECREASE EACH DAY. BRIEF MODERATE RAINFALL IS POSSIBLE AGAIN ON THURSDAY...ALONG WITH GUSTY WINDS. BY FRIDAY AND SATURDAY RAINFALL WILL DECREASE WITH THE THUNDERSTORMS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED LATE THIS AFTERNOON AND THIS EVENING. HTTP://WEATHER.GOV/RENO
The Reno radar (KRGX), 76 km away, was scanning. The volume nearest the first event began at 20:10 UTC.
1 thunderstorm wind. Local standard time, as filed.
A strong thunderstorm downdraft damaged two aircraft at the Soar Truckee facility at the Truckee-Tahoe Airport. The wind gust destroyed an SGS 2-33 aircraft and damaged another glider. No gliders were airborne at the time and no one was injured.
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: 186501.