Alert archive / North Dakota / Severe Thunderstorm Watches in 2018
Severe Thunderstorm Watch 301
The Storm Prediction Center issued this severe thunderstorm watch at Jul 21, 2018, 4:11 PM MDT for 4 states. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 21, 2018, 4:11 PM MDT (22:11 UTC)
- Expired
- Jul 21, 2018, 11:00 PM MDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2.5 in
- Strongest gust expected
- 60 kt
All 25 counties
Carter County, MT, Fallon County, MT, Richland County, MT, Wibaux County, MT, Adams County, ND, Billings County, ND, Bowman County, ND, Dunn County, ND, Golden Valley County, ND, Hettinger County, ND, McKenzie County, ND, Slope County, ND, Stark County, ND, Williams County, ND, Butte County, SD, Custer County, SD, Fall River County, SD, Harding County, SD, Lawrence County, SD, Meade County, SD, Oglala Lakota County, SD, Pennington County, SD, Perkins County, SD, Crook County, WY, Weston County, WY
The radar
The Bismarck radar (KBIS), 233 km from the middle of the area, began a volume at 22:14 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 20%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 60%
- One or more hailstones of 2 inches or more
- 40%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
24 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 21, 4:20 PM MDT | Severe Thunderstorm Warning | GGW | Richland, Roosevelt | 40 min |
| Jul 21, 4:26 PM MDT | Severe Thunderstorm Warning | BYZ | Carter | 34 min |
| Jul 21, 4:34 PM MDT | Severe Thunderstorm Warning | BYZ | Carter | 56 min |
| Jul 21, 4:42 PM MDT | Severe Thunderstorm Warning | BYZ | Carter | 35 min |
| Jul 21, 4:49 PM MDT | Severe Thunderstorm Warning | UNR | Campbell, Weston | 56 min |
| Jul 21, 4:53 PM MDT | Severe Thunderstorm Warning | GGW | Richland, Roosevelt | 67 min |
| Jul 21, 4:56 PM MDT | Severe Thunderstorm Warning | BIS | McKenzie, Williams | 64 min |
| Jul 21, 5:21 PM MDT | Severe Thunderstorm Warning | UNR | Lawrence, Meade, Pennington | 54 min |
| Jul 21, 5:25 PM MDT | Severe Thunderstorm Warning | BYZ | Carter | 22 min |
| Jul 21, 5:41 PM MDT | Severe Thunderstorm Warning | UNR | Campbell, Weston | 38 min |
| Jul 21, 5:56 PM MDT | Severe Thunderstorm Warning | BIS | Dunn, McKenzie, Williams | 64 min |
| Jul 21, 6:12 PM MDT | Severe Thunderstorm Warning | BIS | Golden Valley, Slope | 48 min |
| Jul 21, 6:13 PM MDT | Severe Thunderstorm Warning | UNR | Lawrence, Pennington | 62 min |
| Jul 21, 6:23 PM MDT | Severe Thunderstorm Warning | UNR | Campbell, Weston | 39 min |
| Jul 21, 6:34 PM MDT | Severe Thunderstorm Warning | BIS | Billings, Golden Valley, Slope, Stark | 36 min |
| Jul 21, 6:45 PM MDT | Severe Thunderstorm Warning | UNR | Meade, Pennington | 30 min |
| Jul 21, 6:56 PM MDT | Severe Thunderstorm Warning | BIS | Billings, Dunn | 64 min |
| Jul 21, 7:01 PM MDT | Severe Thunderstorm Warning | UNR | Custer, Pennington | 59 min |
| Jul 21, 7:14 PM MDT | Severe Thunderstorm Warning | BIS | Billings, Golden Valley | 31 min |
| Jul 21, 7:16 PM MDT | Severe Thunderstorm Warning | UNR | Meade, Pennington | 59 min |
| Jul 21, 7:16 PM MDT | Severe Thunderstorm Warning | UNR | Weston | 44 min |
| Jul 21, 7:23 PM MDT | Flash Flood Warning | UNR | Meade, Pennington | 3 hr |
| Jul 21, 7:59 PM MDT | Flash Flood Warning | UNR | Pennington | 3 hr |
| Jul 21, 8:06 PM MDT | Severe Thunderstorm Warning | UNR | Pennington | 39 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Glasgow Intl Airport, MT (KGGW), launched 12:00Z, 10.2 hours before the alert went out and 315 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 637 J/kg
- Mixed-layer CIN
- -421 J/kg
- Mixed-layer LCL
- 1463 m above ground
- 0-6 km bulk shear
- 39 kt
- 0-1 km storm-relative helicity
- 294 m²/s²
- 0-3 km storm-relative helicity
- 287 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.3
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 21, 11:53 AM MDT | Mesoscale Discussion | SPC | Daniels, McCone, Richland, Roosevelt, Sheridan, Valley | 3 hr |
| Jul 21, 1:53 PM MDT | Mesoscale Discussion | SPC | Carter, Custer, Fallon, Powder River, Prairie, Wibaux | 3 hr |
| Jul 21, 5:18 PM MDT | Mesoscale Discussion | SPC | Carter, Dawson, Fallon, Richland, Wibaux | 87 min |
| Jul 21, 12:50 PM MDT | Mesoscale Discussion | SPC | Custer, Fall River | 2 hr |
Nearby
Severe Thunderstorm Watches in North Dakota, 2018Severe Thunderstorm Watches in South Dakota, 2018Severe Thunderstorm Watches in Montana, 2018Every severe thunderstorm watch in 2018
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.