A severe thunderstorm with large hail and strong winds caused damage in Newcastle.
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 UNR wrote it up.
A severe thunderstorm with large hail and strong winds caused damage in Newcastle.
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 Jul 21, 4:57 PM MST, 1 hour 17 minutes earlier.
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 557 PM MDT WED JUL 21 2010 .DISCUSSION...HAVE ADDED THE SOUTHWEST CORNER OF THE CWA INTO THE SEVERE THUNDERSTORM WATCH UNTIL 04Z. OUTFLOW BOUNDARY HAS PUSHED INTO THE EASTERN SLOPES OF THE BLACK HILLS...AND WRAPPED AROUND THE WEST SIDE INTO SUNDANCE. THIS SHOULD SIGNIFICANTLY SUPPRESS CONVECTION ON THE SD PLAINS PER 00Z KUNR SOUNDING. HOWEVER...OVER THE HIGHER TERRAIN THERE IS AN AXIS OF 2KJ/KG MUCAPE FROM THE NE PANHANDLE INTO THE BLACK HILLS/NORTHEAST WY. EXPECT BEST CONVECTION TO DEVELOP IN THESE AREAS OVER THE NEXT COUPLE OF HOURS...EXCEPT WHERE CONVECTION HAS WORKED AIR OVER IN NORTHEASTERN WY. FURTHER EAST...OUTFLOW HAS ALSO WASHED INTO SOUTH CENTRAL SD BEHIND SEVERE BOW IN ABR CWA. && .PREV DISCUSSION... /ISSUED 145 PM MDT WED JUL 21 2010/ DISCUSSION...20Z ANALYSIS SHOWS A SURFACE HIGH SHIFTING TO THE NORTHEAST WITH SOUTHEASTERLY TO NORTHEASTERLY FLOW OVER MUCH OF THE AREA. AT THE UPPER LEVELS...THE WATER VAPOR IMAGERY SHOWS A TROUGH DIGGING OVER THE PACIFIC NW AND SOUTHWESTERLY FLOW OVER THE FORECAST AREA. TONIGHT AND THURSDAY...THUNDERSTORMS WILL LIKELY PERSIST INTO THE OVERNIGHT HOURS GIVEN THE CONSIDERABLE INSTABILITY PRESENT IN MODEL SOUNDINGS AND NOCTURNAL JET DEVELOPING OVER SOUTH CENTRAL SD. A COLD FRONT WILL MOVE IN FROM THE NORTH LATE OVERNIGHT...REACHING RAPID CITY BY EARLY THURSDAY MORNING. CAPPING CIN AND REDUCED SURFACE WIND SHEAR WILL REDUCE THUNDERSTORM COVERAGE THURSDAY...ALTHOUGH A CHANCE OF SEVERE WEATHER WILL REMAIN THURSDAY INTO THURSDAY NIGHT. FOR FRIDAY AND FRIDAY NIGHT...CHANCE OF THUNDERSTORMS CONTINUES AS SURFACE LOW SLIDES EASTWARD AND ASSOCIATED COLD FRONT PUSHES THROUGH THE CWA. AMPLE MOISTURE IN PLACE AS MODELS INDICATE PCP WATER VALUES OF 1.5 INCHES OR 160 PERCENT OF AVERAGE. WINDS AND TEMPERATURES WILL BE TRICKY DUE TO THE FRONTAL POSITION AND TIMING. AT THIS TIME WILL STAY CLOSE TO THE CURRENT FORECAST AND ECMWF SINCE IT SEEMS TO BE TRENDING CLOSER ON THE MODEL TO MODEL RUNS COMPARED TO THE GFS. EXTENDED...A BRIEF DRY PERIOD IS EXPECTED SATURDAY INTO AT LEAST EARLY SUNDAY AS A WEAK RIDGE PASSES OVERHEAD. CHANCES FOR STORMS WILL RETURN BY EARLY NEXT WEEK AS WEST-SOUTHWEST FLOW ALOFT REDEVELOPS. LATEST GFS GUIDANCE IS TRENDING DRIER TOWARD SUNDAY AND MONDAY WITH WEAK RIDGING HOLDING IN PLACE A LITTLE LONGER. WILL KEEP POPS IN UNTIL MORE CONSISTENCY IS SEEN. TEMPERATURES WILL LIKELY REMAIN NEAR OR SLIGHTLY ABOVE AVERAGE. AVIATION...THUNDERSTORMS DEVELOPMENT WILL CONTINUE INTO THIS EVENING AND AFFECT MUCH OF THE AREA OVERNIGHT. LOCAL AND BRIEF MVFR/IFR CONDS AS WELL AS GUSTY WINDS CAN BE EXPECTED IN AND NEAR ANY TSTMS. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && HELGESON
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE RAPID CITY SD 1050 AM MDT WED JUL 21 2010 SDZ001-002-012>014-024>032-041>044-046-047-049-072>074-WYZ054>058- 071-221300- 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- 1050 AM MDT (1150 AM CDT) WED JUL 21 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN SOUTH DAKOTA AND NORTHEASTERN WYOMING. .DAY ONE...TODAY AND TONIGHT SCATTERED THUNDERSTORMS WILL BE PRESENT OVER THE AREA THIS MORNING. WITH DAYTIME HEATING...THUNDERSTORMS WILL INCREASE IN COVERAGE THIS AFTERNOON. SOME STORMS MAY BE SEVERE WITH STRONG WINDS...LARGE HAIL...AND PERHAPS AN ISOLATED TORNADO OVER SOUTH-CENTRAL SOUTH DAKOTA. LOCALLY HEAVY RAIN IS ALSO POSSIBLE. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY THERE IS A DAILY CHANCE OF THUNDERSTORMS FROM WEDNESDAY THROUGH FRIDAY. SATURDAY LOOKS LIKE THE LONE DRY DAY...WITH THUNDERSTORM CHANCES RETURNING FOR SUNDAY AFTERNOON THROUGH TUESDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED TODAY.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE RAPID CITY SD 431 PM MDT WED JUL 21 2010 WYZ054-055-057-212315- NORTHERN CAMPBELL WY-SOUTHERN CAMPBELL WY-WYOMING BLACK HILLS WY- 431 PM MDT WED JUL 21 2010 ...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL CROOK AND CENTRAL CAMPBELL COUNTIES UNTIL 515 PM MDT... AT 429 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM WESTON TO 16 MILES SOUTH OF WYODAK...AND MOVING EAST AT 35 MPH. HAIL UP TO THE SIZE OF PENNIES AND WIND GUSTS UP TO 40 MPH ARE EXPECTED WITH THESE STORMS...ALONG WITH HEAVY RAIN. LOCATIONS NEAR THE PATH OF THESE STORMS INCLUDE... GILLETTE... WESTON... ROZET... THIS INCLUDES INTERSTATE 90 BETWEEN WYOMING MILE MARKERS 115 AND 147... THESE STORMS MAY INTENSIFY...AND A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR THIS AREA. BE CERTAIN TO MONITOR LOCAL RADIO AND TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS...FOR ADDITIONAL INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE. TORRENTIAL RAIN...WHICH MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND UNDERPASSES...IS ALSO LIKELY. DO NOT DRIVE YOUR VEHICLE ON A FLOODED ROADWAY. WETENKAMP
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RAPID CITY SD
459 PM MDT WED JUL 21 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0447 PM HAIL 9 SSE DOWNTOWN GILLETTE 44.16N 105.45W
07/21/2010 E0.88 INCH CAMPBELL WY TRAINED SPOTTER
PEA TO NICKEL SIZE HAIL. MOSTLY PEAS.
&&
NWS UNRPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RAPID CITY SD
502 PM MDT WED JUL 21 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0451 PM TSTM WND GST 5 S ROZET 44.21N 105.20W
07/21/2010 E60 MPH CAMPBELL WY NWS EMPLOYEE
&&
CALDERONPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RAPID CITY SD
507 PM MDT WED JUL 21 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0354 PM TSTM WND GST ECHETA 44.45N 105.86W
07/21/2010 M76 MPH CAMPBELL WY MESONET
&&
CALDERONPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RAPID CITY SD
516 PM MDT WED JUL 21 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0514 PM HAIL 12 W UPTON 44.10N 104.86W
07/21/2010 M1.75 INCH WESTON WY TRAINED SPOTTER
&&
MERICKSOPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RAPID CITY SD
531 PM MDT WED JUL 21 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0523 PM HAIL 12 W UPTON 44.10N 104.86W
07/21/2010 E2.00 INCH WESTON WY TRAINED SPOTTER
0523 PM TSTM WND GST 12 W UPTON 44.10N 104.86W
07/21/2010 E70.00 MPH WESTON WY TRAINED SPOTTER
0523 PM TSTM WND DMG 12 W UPTON 44.10N 104.86W
07/21/2010 WESTON WY TRAINED SPOTTER
TREE BRANCHES 3-4 INCHES DIAMETER BROKEN, WINDOW BROKEN
&&
MERICKSOThe Rapid City radar (KUDX), 115 km away, was scanning. The volume nearest the first event began at 01:11 UTC.
1 thunderstorm wind, 1 hail. Local standard time, as filed.
Wind gusts estimated at 70 mph caused minor damage in Newcastle, including trees and branches blown down.
Quarter sized hail fell in Newcastle and east of town.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2010Every state in 2010This day in weather historyWarnings in Wyoming, July 2010
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: 239696, 239697.