A slow-moving thunderstorm in the Glenshire area of Truckee produced very heavy rain (over 2 inches in one hour) as well as several inches of accumulating hail on the 15th.
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The episode as NWS REV wrote it up.
A slow-moving thunderstorm in the Glenshire area of Truckee produced very heavy rain (over 2 inches in one hour) as well as several inches of accumulating hail on the 15th.
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 Aug 15, 12:52 PM PST, 2 hours 38 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RENO NV 152 PM PDT WED AUG 15 2012 .SHORT TERM... ADJUSTED THE POSITION OF THE BEST POP FOR TONIGHT AND LOWERED POP FOR THURSDAY, OTHERWISE NO SIGNIFICANT CHANGES TO THE SHORT TERM FORECAST. THIS MORNING, THE RENO SOUNDING CAME IN WITH A NOTABLE CAP BETWEEN 450-425 MB. IN ADDITION, AN UPPER DISTURBANCE IS CURRENTLY MOVING OVER MONO AND MINERAL COUNTIES WITH SOME LIGHT SUBSIDENCE ALOFT LIKELY BEHIND THE WAVE. THE CAP AND THE PASSAGE OF THE WAVE IS GIVING CONVECTION A HARD TIME OVER THE SIERRA SOUTH OF LAKE TAHOE. HOWEVER, FURTHER NORTH AND EAST AHEAD OF THE UPPER WAVE, THERE ARE SOME HIGH LEVEL CLOUDS AND COOLING IN THE WATER VAPOR SATELLITE FOR EVIDENCE OF LARGE SCALE LIFT. IN ADDITION, MODELS AND TRENDS IN THE SURFACE PRESSURE GRADIENT FROM CALIFORNIA TO NEVADA INDICATE THE POSSIBILITY OF A WESTERLY WIND PUSH TO AID LOW LEVEL CONVERGENCE FOR STORMS OVER WESTERN NEVADA AND NORTHEAST CALIFORNIA (NORTH OF LAKE TAHOE). THEREFORE, I HAVE PUSHED THE BEST SHOT FOR CONVECTION THIS EVENING OUT OF THE SIERRA AND NORTH OF LAKE TAHOE. FOR LATER TONIGHT, I HAVE REDUCED THE COVERAGE OF SHOWERS TO NORTH OF FALLON AND PYRAMID LAKE AND REMOVED THUNDER ALTOGETHER. IT MAY EVEN BE TOO OPTIMISTIC TO LEAVE ANYTHING AT ALL WITH SOME DRIER AIR BELOW 600 MB, POOR LAPSE RATES, AND DUE TO THE FACT THAT THE UPPER WAVE WILL BE PASSING BY MOST OF NEVADA AND NORTHERN CALIFORNIA BY LATE EVENING. THURSDAY LOOKS LIKE A QUIETER DAY FOR MOST OF EASTERN CALIFORNIA AND WESTERN NEVADA AS SOME DRIER AIR WORKS INTO THE REGION BEHIND THIS EVENING'S WAVE. STILL, THERE COULD BE A FEW STORMS SOUTH OF HIGHWAY 50 AND OVER EASTERN LASSEN COUNTY AND NORTHERN WASHOE COUNTY IN THE FAVORED CONVERGENCE AREAS. FRIDAY AND FRIDAY NIGHT, MOISTURE MOVING AROUND THE WESTERN RIDGE AND REMNANT MOISTURE FROM CURRENT TROPICAL DEPRESSION HECTOR WILL SURGE NORTH BETWEEN THE UPPER RIDGE AND AN UPPER LOW OFF THE CALIFORNIA COAST. THIS WILL BRING BACK A HIGHER CHANCE FOR SHOWERS AND STORMS BY FRIDAY AFTERNOON WITH A THREAT FOR OVERNIGHT SHOWERS FRIDAY NIGHT AND EARLY SATURDAY FOR SOME AREAS WITH COPIOUS AMOUNTS OF MID AND HIGH LEVEL MOISTURE. SATURDAY, A SLIGHT CHANCE OF THUNDERSTORMS LOOKS GOOD AREA-WIDE AS RESIDUAL MOISTURE AND A WEST WIND PUSH IN THE AFTERNOON SUPPORTS THE POSSIBILITY OF AT LEAST SOME CONVECTION. SNYDER .LONG TERM...SUNDAY THROUGH WEDNESDAY... FEW CHANGES WERE MADE TO THE EXTENDED FORECAST AS CONFIDENCE REMAINS BELOW AVERAGE WITH PATTERN FOR EARLY NEXT WEEK. FORECASTER CONFIDENCE IS HIGH FOR A PATTERN CHANGE THIS WEEKEND, BUT TIMING AND PLACEMENT OF LARGE SCALE FEATURES IS UNCERTAIN AT THIS TIME. RIDGE AXIS PROGGED TO MOVE EASTWARD TOWARDS THE ROCKIES THIS WEEKEND ALLOWING AN AREA OF LOW PRESSURE TO EDGE CLOSER TO THE WESTERN U.S. UPPER LEVEL FLOW WILL TRANSITION FROM SOUTHERLY TO SOUTHWEST FLOW AS THE LOW PRESSURE APPROACHES THE SIERRA AND WESTERN NEVADA. DEEPER MOISTURE WILL BEGIN TO SHIFT EASTWARD ALONG THE WESTERN PERIPHERY OF THE RIDGE, SO CHANCES FOR THUNDERSTORMS WILL WANE BY EARLY NEXT WEEK. BEST CHANCES FOR THUNDERSTORMS REMAIN SOUTH OF INTERSTATE 80 FOR EARLY IN THE WEEK AND THEN MOVE FURTHER EAST OF HIGHWAY 95 BY MIDWEEK. TROUGH PASSAGE IS TRICKY AS THE GFS, GEM, AND ECMWF CANNOT SEEM TO AGREE ON TIMING AND STRENGTH OF THE EXITING HIGH PRESSURE. EC MAINTAINS THAT HIGH PRESSURE WILL DEFLECT LOW PRESSURE NORTH OF THE REGION ACROSS THE PACIFIC NORTHWEST, WHICH WOULD KEEP THE SIERRA AND WESTERN NEVADA FAIRLY DRY. GFS SWINGS THE TROUGH DIRECTLY ACROSS THE AREA ALONG INTERSTATE 80, WHICH COULD BRING COOLING ALOFT AND AN INCREASED POTENTIAL FOR SHOWERS AND THUNDERSTORMS. WITH MODELS NOT QUITE IN AGREEMENT WITH HOW TO HANDLE THE EXITING RIDGE AND THE APPROACHING TROUGH, MAINTAINED FORECAST AS IS. FORECAST CONSERVATIVELY NUDGED TOWARDS THE GFS, WHICH LEADS TO COOLER AND MORE UNSETTLED WEATHER BY NEXT WEEK, WITH A RETURN OF DRIER CONDITIONS BY LATE NEXT WEEK. LINDAMAN && .AVIATION... SHOWERS AND THUNDERSTORMS WITH GUSTY OUTFLOW WINDS, LOCALLY HEAVY DOWNPOURS AND SMALL HAIL ARE POSSIBLE THROUGH THIS EVENING. AREAS OF SMOKE AND HAZE MAY SETTLE AT KRNO/KTRK THURSDAY MORNING, RESULTING IN REDUCED VISIBILITIES. THERE IS A 25 PERCENT CHANCE OF PATCHY FOG THROUGH THE MARTIS VALLEY, INCLUDING AT KTRK, THROUGH 15Z. LINDAMAN && .REV WATCHES/WARNINGS/ADVISORIES... NV...NONE. CA...NONE. && FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT... HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RENO NV 707 AM PDT WED AUG 15 2012 CAZ070>073-NVZ001>005-161200- 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- 707 AM PDT WED AUG 15 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE EASTERN SIERRA... NORTHEAST CALIFORNIA AND WESTERN NEVADA. .DAY ONE...TODAY AND TONIGHT AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE REGION TODAY BRINGING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS. SCATTERED THUNDERSTORMS CAN BE EXPECTED THIS AFTERNOON AND EVENING ACROSS THE EASTERN SIERRA AND WESTERN NEVADA. STORM MOTIONS WILL BE SLOW WHICH WILL INCREASE THE POSSIBILITY OF LOCALLY HEAVY RAINFALL AND FLASH FLOODING. GUSTY OUTFLOW WINDS OF UP TO 50 MPH ARE ALSO POSSIBLE. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY SHOWERS AND THUNDERSTORMS WILL AGAIN BE POSSIBLE EACH DAY THURSDAY THROUGH SUNDAY. A DRYING PATTERN IS FORECAST BEGINNING NEXT WEEK. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED AT THIS TIME. HOWEVER... SPOTTERS ARE ASKED TO REMAIN ALERT AND REPORT SIGNIFICANT WEATHER TO THE NATIONAL WEATHER SERVICE. O'HARA FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT... HTTP://FORECAST.WEATHER.GOV/HAZARDS/REV (ALL LOWER CASE)
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RENO NV 359 PM PDT WED AUG 15 2012 NVZ002-003-152345- GREATER LAKE TAHOE AREA-GREATER RENO-CARSON CITY-MINDEN AREA- 359 PM PDT WED AUG 15 2012 ...THUNDERSTORM WITH HEAVY RAIN NEAR GALENA... AT 358 PM PDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING A STRONG THUNDERSTORM 3 MILES NORTH OF GALENA...OR 8 MILES SOUTH OF RENO. THIS STORM WAS NEARLY STATIONARY. OCCASIONAL LIGHTNING...HEAVY RAIN WITH AMOUNTS UP TO ONE INCH PER HOUR AND GUSTY WINDS TO 40 MPH ARE OCCURRING WITH THIS STORM. * LOCATIONS AFFECTED INCLUDE...GALENA...SOUTH RENO. HEAVY RAINFALL IS OCCURRING WITH THIS STORM IN THE WHITES AND THOMAS CREEK AREA. PONDING OF WATER MAY OCCUR IN ARROWCREEK AND PORTIONS OF SOUTH RENO. DRIVERS SHOULD SLOW DOWN AND TURN ON THEIR HEADLIGHTS IF ENCOUNTERING HEAVY RAINS. && LAT...LON 3948 11993 3947 11981 3935 11979 3936 11993 TIME...MOT...LOC 2255Z 141DEG 1KT 3943 11985 BRONG
The national radar mosaic for the moment the first event began.
1 hail. Local standard time, as filed.
Very large amounts of pea to marble size hail (with some hail as large as nickels) from a slow-moving thunderstorm caused around 4 inches of accumulating hail. The hail depth was directly verified by a National Weather Service employee. The hail caused a number of residential gardens to be damaged or destroyed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2012Every state in 2012This day in weather historyWarnings in California, August 2012
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: 406991.