A severe thunderstorm clipped northern Tripp County, producing strong wind gusts north of Hamill and a brief tornado that caused minor damage on a farm.
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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 clipped northern Tripp County, producing strong wind gusts north of Hamill and a brief tornado that caused minor damage on a farm.
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 18, 5:14 PM CST, 1 hour 16 minutes earlier.
Area Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 514 PM MDT Wed Jul 18 2018 .DISCUSSION...(This Evening Through Wednesday) Issued at 155 PM MDT Wed Jul 18 2018 Water vapor imagery depicts a shortwave trough crossing the Dakotas this afternoon. The main midlevel vort max appears to be over northwestern SD/southwestern ND, with a secondary vort max over central SD. An anomalously moist warm sector extends from the Lower Mississippi Valley northwestward through southern Manitoba/Saskatchewan, with dew points in the 60s across much of our area. A wind shift boundary stretches across northeastern WY/northwestern SD, with southerly/southwesterly flow ahead of the boundary and northwesterly flow behind. Thunderstorm development this afternoon should be focused in three regions. The first will be near the Black Hills, where one or two storms could develop in a relatively low-to-moderate CAPE environment with plentiful, albeit largely unidirectional, deep- layer shear. Severe threat should overall be limited, but marginally severe hail or wind could be possible here. The second region is over northwestern SD, where activity is ongoing near the primary midlevel vort max. CAPE is limited here, as well, but enhanced low-level SRH could contribute to a larger threat for persistent supercells capable of damaging winds and marginally severe hail. A tornado also cannot be ruled out in a region of locally backed flow near the aforementioned wind shift boundary. Finally, strong to severe storms are expected to develop over central/south central SD this afternoon and continue through the evening. CAPE over 2000 J/kg, deep-layer bulk shear approaching 50 kt, low-level SRH over 300 m2/s2, and abundant low-to-midlevel moisture will support supercells capable of all severe hazards, including tornadoes. It is plausible that this development could occur largely east of our area given recent CAM trends, but still think a few storms will clip our southeastern zones. Lower PWATs overspread the area from west to east on Thursday as upper ridging builds over the region. This should spell the end to convection for at least a couple of days. As a surface ridge shifts east of the area late this week into early in the weekend, moisture return should provide anomalously high PWATs (above 90th percentile) across much of the area again. Thus, despite limited large-scale forcing, may still begin to see isolated/scattered storms across the Black Hills/SD plains on Saturday due to upslope low-level flow. Some of these storms could produce locally heavy rainfall, and we will need to keep an eye on the threat for severe hazards. General model consensus suggests an upper-level shortwave and attendant surface front will cross the area late weekend, which will support more widespread showers and storms across portions of the area. Solutions differ on moisture availability into early next week as the upper ridge flattens and we transition to zonal flow aloft. && .AVIATION...(For the 00Z TAFS Through 00Z Thursday Evening) Issued At 513 PM MDT Wed Jul 18 2018 TSRA with MVFR/local IFR conditions are expected across the central SD plains early this evening. Severe storms with heavy rainfall will be possible. Otherwise VFR conditions are expected through the forecast period. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. && DISCUSSION...Sherburn AVIATION...13
Hazardous Weather Outlook National Weather Service Rapid City SD 736 AM MDT Wed Jul 18 2018 SDZ046-047-049-191315- Mellette-Todd-Tripp- 836 AM CDT Wed Jul 18 2018 This Hazardous Weather Outlook is for portions of south central South Dakota. .DAY ONE...Today and Tonight Scattered showers and thunderstorms are expected again today. Severe storms capable of producing damaging winds, large hail, and tornadoes will be possible. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed today. && Stay tuned to NOAA weather radio for further updates...or check our web site at weather.gov/rapidcity SDZ001-002-012>014-024>026-028>032-042>044-072>074-191315- Harding-Perkins-Butte-Northern Meade Co Plains-Ziebach- Northern Black Hills-Northern Foot Hills-Rapid City- Central Black Hills-Southern Black Hills-Custer Co Plains- Pennington Co Plains-Haakon-Oglala Lakota-Jackson-Bennett- Sturgis/Piedmont Foot Hills-Southern Meade Co Plains- Hermosa Foot Hills- 736 AM MDT Wed Jul 18 2018 This Hazardous Weather Outlook is for portions of northwestern South Dakota...southwestern South Dakota...and the Black Hills of South Dakota. .DAY ONE...Today and Tonight Isolated showers and thunderstorms are expected again today. A few storms may be severe, with damaging winds and large hail the primary concerns. Locally heavy rainfall will be possible in any thunderstorms. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed today. && Stay tuned to NOAA weather radio for further updates...or check our web site at weather.gov/rapidcity SDZ027-WYZ057-071-191315- Southern Foot Hills-Wyoming Black Hills-Northeastern Crook- 736 AM MDT Wed Jul 18 2018 This Hazardous Weather Outlook is for portions of southwestern South Dakota...northeast Wyoming...and the Black Hills of Wyoming. .DAY ONE...Today and Tonight Isolated showers and thunderstorms are possible this afternoon. Severe weather is not expected at this time. Locally heavy rainfall will be possible in any thunderstorms. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed today. && Stay tuned to NOAA weather radio for further updates...or check our web site at weather.gov/rapidcity SDZ041-WYZ054>056-058-191315- Fall River-Northern Campbell-Southern Campbell-Western Crook- Weston- 736 AM MDT Wed Jul 18 2018 This Hazardous Weather Outlook is for portions of southwestern South Dakota...and northeast Wyoming. .DAY ONE...Today and Tonight No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed today. && Stay tuned to NOAA weather radio for further updates...or check our web site at weather.gov/rapidcity
Special Weather Statement
National Weather Service Rapid City SD
500 PM CDT WED JUL 18 2018
SDZ047-049-182245-
Tripp SD-Todd SD-
500 PM CDT WED JUL 18 2018
...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN TODD AND
SOUTHWESTERN TRIPP COUNTIES UNTIL 545 PM CDT...
At 500 PM CDT, Doppler radar was tracking a strong thunderstorm near
Littleburg, or 19 miles southeast of Mission, moving east at 35 mph.
Dime size hail and winds in excess of 40 mph will be possible with
this storm.
Locations impacted include...
Millboro, Keyapaha, Wewela and Littleburg.
A tornado watch remains in effect until 1100 PM CDT for south central
South Dakota.
LAT...LON 4304 10053 4315 10044 4319 10028 4309 9974
4300 9978 4299 9980 4300 10051
TIME...MOT...LOC 2200Z 282DEG 30KT 4308 10043
SherburnPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RAPID CITY SD
404 PM MDT WED JUL 18 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0251 PM HAIL BOX ELDER 44.12N 103.07W
07/18/2018 M1.75 INCH PENNINGTON SD SOCIAL MEDIA
&&
ARKPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RAPID CITY SD
416 PM MDT WED JUL 18 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0358 PM TSTM WND GST 1 NNE ROCKYFORD 43.51N 102.50W
07/18/2018 E60 MPH OGLALA LAKOTA SD TRAINED SPOTTER
&&
KCLARKPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RAPID CITY SD
424 PM MDT WED JUL 18 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0410 PM HAIL 19 S OKREEK 43.10N 100.34W
07/18/2018 M1.00 INCH TODD SD PUBLIC
&&
ARKPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RAPID CITY SD
445 PM MDT WED JUL 18 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0248 PM HAIL BOX ELDER 44.12N 103.07W
07/18/2018 M2.00 INCH PENNINGTON SD SOCIAL MEDIA
&&
ARKSpecial Weather Statement
National Weather Service Rapid City SD
506 PM MDT WED JUL 18 2018
SDZ032-043-046-182345-
Jackson SD-Haakon SD-Mellette SD-
506 PM MDT WED JUL 18 2018
...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN HAAKON...
NORTHWESTERN MELLETTE AND NORTHEASTERN JACKSON COUNTIES UNTIL 545 PM
MDT/645 PM CDT/...
At 505 PM MDT/605 PM CDT/, Doppler radar was tracking strong
thunderstorms along a line extending from 6 miles northwest of
Midland to 8 miles southwest of Nowlin to 5 miles west of Kadoka.
Movement was east at 25 mph.
Winds in excess of 40 mph will be possible with these storms.
Locations impacted include...
Kadoka, Midland, Belvidere and Nowlin.
This Includes Interstate 90 in South Dakota between Mile Markers 146
and 174.
A tornado watch remains in effect until 1000 PM MDT/1100 PM CDT/ for
south central, southwestern and west central South Dakota.
LAT...LON 4379 10165 4387 10158 4392 10148 4419 10121
4419 10117 4417 10116 4416 10105 4386 10106
4384 10099 4376 10108
TIME...MOT...LOC 2305Z 252DEG 23KT 4415 10122 4395 10140 4385 10162
SherburnThe North Platte radar (KLNX), 204 km away, was scanning. The volume nearest the first event began at 00:30 UTC.
1 thunderstorm wind, 1 tornado. Local standard time, as filed.
The strong winds leveled a shed, broke windows, and snapped trees and power poles.
A brief tornado developed near the intersection of 257th Street and 325th Avenue, six miles north-northeast of Hamill. The tornado tipped over and damaged an irrigation pivot. The tornado was rated an EF-1 with winds estimated near 100 mph.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in South Dakota in 2018Every state in 2018This day in weather historyThe tornado archive for South Dakota, 2018Warnings in South Dakota, July 2018
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: 765774, 765785.