Alert archive / North Dakota / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 645
The Storm Prediction Center issued this severe thunderstorm watch at Jul 14, 2011, 10:01 PM MDT for 4 counties in Montana; 20 counties in North Dakota. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 14, 2011, 10:01 PM MDT (04:01 UTC)
- Expired
- Jul 15, 2011, 3:35 AM MDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 24 counties
Carter County, MT, Custer County, MT, Fallon County, MT, Powder River County, MT, Adams County, ND, Billings County, ND, Bowman County, ND, Burke County, ND, Divide County, ND, Dunn County, ND, Golden Valley County, ND, Grant County, ND, Hettinger County, ND, McKenzie County, ND, McLean County, ND, Mercer County, ND, Morton County, ND, Mountrail County, ND, Oliver County, ND, Renville County, ND, Slope County, ND, Stark County, ND, Ward County, ND, Williams County, ND
The radar
The Bismarck radar (KBIS), 220 km from the middle of the area, began a volume at 04:02 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
- 5%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
10 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 14, 10:29 PM MDT | Severe Thunderstorm Warning | BYZ | Fallon | 46 min |
| Jul 14, 10:42 PM MDT | Severe Thunderstorm Warning | BIS | Billings, Golden Valley, McKenzie | 63 min |
| Jul 15, 12:01 AM MDT | Severe Thunderstorm Warning | BIS | Billings, Dunn | 44 min |
| Jul 15, 12:07 AM MDT | Severe Thunderstorm Warning | BIS | Dunn, McKenzie, Mountrail | 53 min |
| Jul 15, 12:23 AM MDT | Severe Thunderstorm Warning | BIS | Dunn, Mercer, Stark | 37 min |
| Jul 15, 12:43 AM MDT | Severe Thunderstorm Warning | BYZ | Custer | 47 min |
| Jul 15, 12:43 AM MDT | Severe Thunderstorm Warning | BIS | Dunn, McKenzie, McLean, Mercer, Mountrail, Williams | 62 min |
| Jul 15, 1:20 AM MDT | Severe Thunderstorm Warning | BIS | McLean, Mountrail, Ward | 55 min |
| Jul 15, 1:29 AM MDT | Severe Thunderstorm Warning | BYZ | Custer, Fallon | 46 min |
| Jul 15, 2:11 AM MDT | Severe Thunderstorm Warning | BIS | McHenry, Renville, Ward | 49 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
Bismarck Municip, ND (KBIS), launched 00:00Z, 4.0 hours before the alert went out and 225 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
- 2132 J/kg
- Mixed-layer CIN
- -66 J/kg
- Mixed-layer LCL
- 698 m above ground
- 0-6 km bulk shear
- 35 kt
- 0-1 km storm-relative helicity
- 101 m²/s²
- 0-3 km storm-relative helicity
- 76 m²/s²
- Significant tornado parameter
- 0.5
- Supercell composite
- 3.2
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 14, 6:33 PM MDT | Mesoscale Discussion | SPC | Big Horn, Custer, Daniels, Dawson, Garfield, McCone and 11 more | 57 min |
| Jul 15, 1:54 AM MDT | Mesoscale Discussion | SPC | Carter, Dawson, Fallon, Powder River, Richland, Wibaux | 2 hr |
| Jul 15, 2:39 PM MDT | Mesoscale Discussion | SPC | Big Horn, Broadwater, Carbon, Custer, Gallatin, Golden Valley and 13 more | 2 hr |
| Jul 15, 3:26 PM MDT | Severe Thunderstorm Watch | SPC | Big Horn, Carbon, Custer, Golden Valley, Musselshell, Powder River and 4 more | 6 hr |
| Jul 14, 8:46 PM MDT | Mesoscale Discussion | SPC | Adams, Emmons, Grant, Kidder, Logan, McIntosh and 1 more | 59 min |
| Jul 14, 10:55 PM MDT | Mesoscale Discussion | SPC | Barnes, Cass, Dickey, Emmons, Kidder, LaMoure and 6 more | 65 min |
| Jul 15, 1:56 AM MDT | Severe Thunderstorm Watch | SPC | Barnes, Cass, Grand Forks, Griggs, Nelson, Ramsey and 6 more | 7 hr |
| Jul 15, 5:30 AM MDT | Mesoscale Discussion | SPC | Barnes, Cass, Ransom, Richland | 2 hr |
| Jul 15, 5:10 PM MDT | Mesoscale Discussion | SPC | Barnes, Cass, Dickey, LaMoure, Ransom, Richland and 2 more | 65 min |
Nearby
Severe Thunderstorm Watches in North Dakota, 2011Severe Thunderstorm Watches in Montana, 2011Every severe thunderstorm watch in 2011
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.