A severe thunderstorm developed across southern Weston County, producing nickel sized hail and a brief tornado.
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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 UNR wrote it up.
A severe thunderstorm developed across southern Weston County, producing nickel sized hail and a brief tornado.
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 Rapid City, SD wrote its last area forecast discussion before the first event at May 9, 9:30 AM MST, 3 hours 42 minutes earlier.
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 1030 AM MDT FRI MAY 9 2008 .DISCUSSION...16Z SFC ANALYSIS SHOWS LOW PRESSURE OVER EAST CENTRAL WYOMING WITH A TROUGH EXTENDING NORTH INTO NC MONTANA AND SOUTH TO EASTERN COLORADO. WV IMAGERY SHOWING UPPER LOW/TROUGH OVER NW MONTANA DIVING SE. WEAK WAVE AHEAD OF THE UPPER LOW HAS KICKED OFF A FEW SHOWERS OVER PORTIONS OF NE WY AND WRN SOUTH DAKOTA SO HAVE ADJUSTED POPS UPWARD FOR THOSE AREAS FOR THE REST OF THIS MORNING. REST OF THE FORECAST IS STILL ON TRACK. TODAY/SATURDAY...MT UPPER LOW WILL SPIN INTO NORTH CENTRAL SD/SOUTH CENTRAL ND BY 12Z SATURDAY AND THEN MOVE EAST OF THE AREA BY 00Z SUNDAY. SURFACE LOW WILL FORM OVER CENTRAL WY AND MOVE INTO CENTRAL MN BY 00Z SUNDAY. STRONG QG-FORCING EVIDENT WITH MODELS SHOWING SUBSTANTIAL LIFT AND FRONTOGENESIS WITH SYSTEM AS 700MB LOW MOVES ALONG I-90. ANOTHER WIDESPREAD PRECIPITATION EVENT FORESEEN...ESPECIALLY NORTH OF THE LOW TRACK TONIGHT. UP TO 500J/KG CAPE IS AVAILABLE THIS AFTERNOON/EARLY EVENING...LEADING TO ISOLATED TSRA THIS AFTN/EVE. ENOUGH SHEAR AVAILABLE FOR ROTATING UPDRAFTS ESP OVER THE SRN PTNS OF OUR NE WY ZONES AND OVER FAR SW SD...BUT LMITED SOLAR INSOLATION SHOULD PRECLUDE ORGANIZED SEVERE ACTIVITY. AS RAIN OVERSPREADS REGION TONIGHT...DYNAMIC COOLING SUFFICIENT TO TURN HIGHER ELEVATIONS AND NORTHWEST SD PLAINS TO SNOW. 1-4 INCHES OF SNOW ACCUMULATION POSSIBLE LATE FRIDAY NIGHT/EARLY SATURDAY MORNING. QPF LOOKS TO BE 1/4-1/2 INCH ON AVERAGE...BUT 1 INCH AMOUNTS LIQUID LIKELY NORTH. ACTIVITY SHOULD QUICKLY END LATE SATURDAY AND SATURDAY NIGHT. SATURDAY WILL BE QUITE WINDY AS GRADIENT TIGHTENS BEHIND SURFACE LOW. SUNDAY...TRANQUIL WEATHER RETURNS DURING THE DAY...BUT ANOTHER SYSTEM WILL BRING SMALL CHANCES FOR SHOWERS IN THE FAR NORTHWEST AT NIGHT. EXTENDED...AN UPPER LEVEL TROF WILL MOVE INTO THE ROCKIES EARLY IN THE WORK WEEK. ECWMF BRINGS THE TROF AXIS THROUGH THE AREA LATE TUESDAY...WHILE GFS SPLITS A CLOSED LOW OFF OVER THE SOUTHWESTERN CONUS THROUGH STILL BRINGS A WEAKER TROF THRU THE REGION. DECIDED TO GO WITH A CHANCE OF SHOWERS OR THUNDERSTORMS THROUGH TUESDAY...WITH THE CHANCE OF SHOWERS CONTINUING THROUGH THURSDAY AS THE PATTERN REMAINS UNSETTLED. TEMPERATURES WILL COOL TO SLIGHTLY BELOW AVERAGE FOR MUCH OF THE WORK WEEK. && .AVIATION...MVFR CIGS WILL GRADUALLY BECOME VFR LATE THIS MORNING INTO THE EARLY AFTERNOON ACROSS WESTERN SOUTH DAKOTA. AN UPPER LEVEL DISTURBANCE MOVING OVER THE AREA WILL BRING RAIN TO MUCH OF WESTERN SOUTH DAKOTA AND NORTHEASTERN WYOMING THIS EVENING...CREATING AREAS OF MVFR CIGS AND VIS. && .HYDROLOGY...EXPECT CURRENT FLOOD HEADLINES TO CONTINUE. FORECAST QPF WILL CAUSE ADDITIONAL SWELLING OF AREA WATERWAYS...OR AT LEAST KEEP THEM FROM FALLING MUCH OVER THE NEXT 24-48 HOURS. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RAPID CITY SD 541 AM MDT FRI MAY 9 2008 SDZ001-002-012>014-024>032-041>044-046-047-049-072>074-WYZ054>058- 071-101300- BENNETT-BUTTE-CENTRAL BLACK HILLS-CUSTER CO PLAINS-FALL RIVER-HAAKON- HARDING-HERMOSA FOOT HILLS-JACKSON-MELLETTE-NORTHEASTERN CROOK- NORTHERN BLACK HILLS-NORTHERN CAMPBELL-NORTHERN FOOT HILLS- NORTHERN MEADE CO PLAINS-PENNINGTON CO PLAINS-PERKINS-RAPID CITY- SHANNON-SOUTHERN BLACK HILLS-SOUTHERN CAMPBELL-SOUTHERN FOOT HILLS- SOUTHERN MEADE CO PLAINS-STURGIS/PIEDMONT FOOT HILLS-TODD-TRIPP- WESTERN CROOK-WESTON-WYOMING BLACK HILLS-ZIEBACH- 541 AM MDT (641 AM CDT) FRI MAY 9 2008 ...FLOOD WARNING FOR THE LITTLE MISSOURI RIVER AT CAMP CROOK UNTIL LATE SATURDAY NIGHT... ...FLOOD WARNING FOR LAWRENCE...SOUTHWESTERN MEADE...SOUTHEASTERN CROOK AND EXTREME SOUTHWESTERN BUTTE COUNTIES UNTIL SUNDAY AFTERNOON... ...SMALL STREAM FLOOD ADVISORY FOR BUTTE AND HARDING COUNTIES UNTIL SATURDAY AFTERNOON... THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN SOUTH DAKOTA AND NORTHEASTERN WYOMING. .DAY ONE...TODAY AND TONIGHT A NEW STORM SYSTEM WILL IMPACT THE AREA THIS AFTERNOON AND TONIGHT. IT WILL BRING WIDESPREAD RAIN SHOWERS WITH 1/2 TO 1 INCH RAIN AMOUNTS ACROSS PORTIONS OF NORTHWESTERN SOUTH DAKOTA. LOCALLY HIGHER AMOUNTS ARE POSSIBLE. LATER TONIGHT...THE RAIN WILL MIX WITH OR CHANGE TO SNOW LEADING TO 1 TO 4 INCHES OF ACCUMULATION ACROSS THE HIGHER ELEVATIONS OF THE BLACK HILLS AND FAR NORTHWESTERN SOUTH DAKOTA. THE ADDITIONAL RAINFALL WILL KEEP CREEKS AND STREAMS ELEVATED OVER THE NORTHERN BLACK HILLS TO FAR NORTHWESTERN SOUTH DAKOTA THROUGH THE WEEKEND. SNOWMELT FROM THE HIGHER ELEVATIONS OF THE BLACK HILLS WILL ALSO ALSO CONTRIBUTE TO WATER FLOWS. A VARIETY OF FLOOD PRODUCTS WILL REMAIN IN EFFECT. ISOLATED THUNDERSTORMS WILL OCCUR THIS AFTERNOON AND EARLY EVENING. ALTHOUGH WIDESPREAD SEVERE THUNDERSTORMS ARE NOT EXPECTED...THERE IS AN OUTSIDE CHANCE FOR A SEVERE THUNDERSTORM GENERALLY SOUTH OF CUSTER. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY RUNOFF FROM PRECIPITATION TODAY AND TONIGHT WILL CONTINUE TO CAUSE SWOLLEN CREEKS AND STREAMS FROM THE NORTHERN BLACK HILLS INTO FAR NORTHWESTERN SOUTH DAKOTA FOR SATURDAY AND SUNDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY.
The Rapid City radar (KUDX), 176 km away, was scanning. The volume nearest the first event began at 20:10 UTC.
1 tornado, 1 hail. Local standard time, as filed.
A small tornado was on the ground for about three minutes in open country. It caused no damage. Two brief funnels were observed between 2:00 and 2:10 pm MDT.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2008Every state in 2008This day in weather historyThe tornado archive for Wyoming, 2008Warnings in Wyoming, May 2008
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: 102902, 87111.