Low pressure off the central California coast contributed to the formation of thunderstorms in the Sierra on the 20th.
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The episode as NWS REV wrote it up.
Low pressure off the central California coast contributed to the formation of thunderstorms in the Sierra on the 20th.
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 20, 1:46 PM PST, 2 hours 9 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RENO NV 246 PM PDT TUE AUG 20 2013 .SYNOPSIS... AN UPPER LEVEL LOW OFF THE CALIFORNIA COAST WILL TRACK ACROSS NORTHERN CALIFORNIA OVER THE NEXT FEW DAYS. THIS WILL PROVIDE A THREAT FOR THUNDERSTORMS WITH HEAVY RAINFALL ACROSS THE REGION WEDNESDAY INTO THURSDAY. THIS LOW WILL THEN MOVE NORTH ACROSS OREGON LATE THURSDAY AND DECREASE THE CHANCE FOR SHOWERS AND STORMS. FROM FRIDAY THROUGH EARLY NEXT WEEK, DRIER CONDITIONS AND NEAR NORMAL TEMPERATURES ARE EXPECTED. && .SHORT TERM... AN UPPER LOW OFF THE CENTRAL CALIFORNIA COAST IS SLOWLY TRACKING NORTHWARD THIS AFTERNOON. WATER VAPOR SATELLITE IS SHOWING A DRY SLOT CROSSING INTO CALIFORNIA AND WESTERN NEVADA. THIS HAS DELAYED THE ONSET OF CONVECTION THIS AFTERNOON BUT WITH CLEARER CONDITIONS AND SIGNS OF MOISTURE RECOVERY ON THE MAMMOTH LAKES GPS IPW SENSOR, DO EXPECT HEATING TO POP SHOWERS AND STORMS BY LATE AFTERNOON AND INTO EARLY EVENING. THESE STORMS HAVE THE POTENTIAL TO PRODUCE STRONG OUTFLOW WINDS AND LOCALIZED AREAS OF HEAVY RAINFALL. ON WEDNESDAY, MOISTURE WILL REMAIN WELL ABOVE NORMAL FOR THIS TIME OF YEAR WITH COLUMN MOISTURE APPROACHING 1 INCH. THIS IS AROUND 3 STANDARD DEVIATIONS ABOVE NORMAL. THE APPROACHING LOW WILL PRODUCE BETTER FORCING ALOFT TO TAP INTO AMPLE MOISTURE AND WIDESPREAD INSTABILITY (L.I.~ -3, HLTT~34, CAPES APPROACHING 1000J/KG). THIS WILL PROVIDE OUR BEST CHANCES FOR WIDESPREAD SHOWERS AND STORMS WHICH MAY BECOME SEVERE WITH HEAVY RAINFALL AND LOCALIZED FLASH FLOODING, HAIL, STRONG WIND GUSTS, AND FREQUENT LIGHTNING. WINDS ALOFT WILL BE SWIFT SO EXPECTING QUICK STORM MOTIONS, BUT THE MAIN FLASH FLOOD THREAT WILL COME IN THE FORM OF TRAINING STORMS AND POSSIBLE BACK-BUILDING DEVELOPMENT. THE BEST AREA FOR DEVELOPMENT ON WEDNESDAY WILL BE ALONG THE SIERRA AND WESTERN NEVADA NORTH OF HIGHWAY 50. THERE IS GOOD POTENTIAL FOR THESE SHOWERS AND STORMS TO CONTINUE OVERNIGHT AND INTO THURSDAY MORNING AS THE CORE OF THE LOW PUSHES ACROSS NORTHERN CALIFORNIA PROVIDING DIVERGENCE ALOFT AND JET SUPPORT ACROSS NE CA AND NW NEVADA. ON THURSDAY, THE LOW PUSHES ACROSS NORTHERN CALIFORNIA AND WILL PROVIDE ADDITIONAL CHANCES FOR SHOWERS AND STORMS WITH HEAVY RAINFALL MAINLY ACROSS FAR NORTHEAST CALIFORNIA AND NORTHWEST NEVADA THURSDAY AFTERNOON. DRIER AIR AND BREEZY CONDITIONS WILL PREVAIL ACROSS THESE AREAS AS THE LOW PUSHES INTO SOUTHERN OREGON BY THURSDAY EVENING. FUENTES .LONG TERM...FRIDAY THROUGH TUESDAY... DRIER SOUTHWEST FLOW RETURNS FRIDAY AS A TROUGH SETS UP OFF THE PACIFIC NORTHWEST COAST WITH A RIDGE OVER DESERT SOUTHWEST AND SOUTHERN PLAINS. WITH STRONG RIDGING REMAINING WELL EAST OF THE REGION, HIGH TEMPERATURES WILL STAY WITHIN A FEW DEGREES OF AVERAGE THROUGH EARLY NEXT WEEK. WINDS SHOULD KICK UP IN THE AFTERNOON AND EVENING TO RATHER TYPICAL SUMMER VALUES WITH PEAK GUSTS 25-30 MPH. AS FAR AS THE POTENTIAL FOR MOISTURE RETURN EARLY NEXT WEEK, MOST MODELS/ENSEMBLES NOW IMPLY THAT MOISTURE WOULD BE KEPT SOUTH AND EAST OF THE SIERRA AND WESTERN NEVADA AS DRY SOUTHWEST FLOW ALOFT PREVAILS. THEREFORE, THE PROBABILITY FOR PRECIPITATION/THUNDERSTORMS REMAINS VERY LOW THROUGH THE LONG TERM FORECAST. SNYDER && .AVIATION... AN UPPER LOW WILL PROVIDE A THREAT FOR SHOWERS AND THUNDERSTORMS ACROSS ALL TERMINALS THROUGH WEDNESDAY NIGHT. SHOWERS AND STORMS THIS AFTERNOON WILL DEVELOP AFTER 22Z ACROSS SIERRA TERMINALS, THEN DIMINISH AFTER SUNSET. KRNO/KCXP COULD SEE TSRA AFT 00Z WITH VCSH THRU ABOUT 06Z. WEDNESDAY WILL SEE THE BEST POTENTIAL FOR WIDESPREAD TSRA ACROSS THE SIERRA AND WESTERN NEVADA WITH STORMS POSSIBLY DEVELOPING BY LATE WED MORNING IN THE SIERRA. THE STRONGER STORMS ON WED WILL PRODUCE HEAVY RAIN, HAIL, OUTFLOW WINDS TO 45 KTS, PERIODS OF MVFR/IFR CONDITIONS, AND HIGHER TERRAIN OBSCURATION. FUENTES && .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 255 PM PDT TUE AUG 20 2013 CAZ070>073-NVZ001>005-211300- 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- 255 PM PDT TUE AUG 20 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE EASTERN SIERRA... NORTHEAST CALIFORNIA AND WESTERN NEVADA. .DAY ONE...THIS AFTERNOON AND TONIGHT SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS IN THE SIERRA... WESTERN NEVADA...AND NORTHEAST CALIFORNIA. STRONGER STORMS MAY PRODUCE HEAVY RAIN...SMALL HAIL AND WIND GUSTS TO 50 MPH. A FEW STORMS MAY LAST INTO THE LATE EVENING ESPECIALLY IN THE NORTHERN SIERRA. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THUNDERSTORMS WILL CONTINUE ON WEDNESDAY. ABUNDANT MOISTURE AND SIGNIFICANT INSTABILITY WILL INCREASE THE CHANCES FOR SEVERE STORMS WITH LARGE HAIL AND FLASH FLOODING. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER TO THE NATIONAL WEATHER SERVICE ACCORDING TO STANDARD OPERATING PROCEDURE. REPORTS OF SEVERE WEATHER ARE ALSO WELCOME BY POSTING TO THE NATIONAL WEATHER SERVICE RENO FACEBOOK PAGE...OR ON TWITTER USING...AT NWSRENO. 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 419 PM PDT TUE AUG 20 2013 CAZ072-NVZ002-003-210015- GREATER LAKE TAHOE AREA-GREATER RENO-CARSON CITY-MINDEN AREA- 419 PM PDT TUE AUG 20 2013 ...THUNDERSTORMS MOVING UP THE CARSON RANGE... AT 414 PM PDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING A STRONG THUNDERSTORM 6 MILES SOUTHWEST OF GARDNERVILLE...AND MOVING NORTHWEST AT 10 TO 15 MPH. FREQUENT DEADLY LIGHTNING...HEAVY RAIN WITH AMOUNTS NEAR ONE INCH PER HOUR...PENNY SIZE HAIL...AND GUSTY WINDS TO 45 MPH...WILL OCCUR WITH THIS STORM. WIND GUSTS MAY AFFECT BOATERS ON LAKE TAHOE BETWEEN 430 PM AND 600 PM. * LOCATIONS AFFECTED THROUGH 515 PM PDT INCLUDE...DAGGET PASS... GARDNERVILLE...GARDNERVILLE RANCH...GENOA...GLENBROOK AND KINGSBURY. IF ON OR NEAR A LAKE...GET OUT OF THE WATER AND MOVE INDOORS OR INSIDE A VEHICLE NOW. DON'T BE CAUGHT ON THE WATER IN A THUNDERSTORM. STRONG WIND GUSTS AND LIGHTNING POSE AN IMMEDIATE DANGER TO BOATERS. GUSTY WINDS WILL CAUSE A RAPID INCREASE IN WAVE HEIGHTS WHICH MAY CAPSIZE SMALL BOATS. && LAT...LON 3908 12007 3919 11987 3887 11968 3877 11987 TIME...MOT...LOC 2317Z 148DEG 8KT 3890 11984 HOHMANN
The Reno radar (KRGX), 100 km away, was scanning. The volume nearest the first event began at 23:54 UTC.
1 hail. Local standard time, as filed.
Penny to nickel hail was reported in South Lake Tahoe with hail accumulations up to 2 inches deep.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2013Every state in 2013This day in weather historyWarnings in California, August 2013
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: 473980.