Alert archive / North Dakota / Severe Thunderstorm Watches in 2005

Severe Thunderstorm Watch 309

May 21, 20059 counties in Minnesota; 35 counties in North Dakota; 5 counties in South Dakota

The Storm Prediction Center issued this severe thunderstorm watch at May 21, 2005, 1:35 AM CDT for 9 counties in Minnesota; 35 counties in North Dakota; 5 counties in South Dakota. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued: May 21, 2005, 1:35 AM CDT (06:35 UTC)
Expired: May 21, 2005, 9:00 AM CDT
In force: 7 hr
Issued by: the Storm Prediction Center

All 49 counties

Becker County, MN, Clay County, MN, Mahnomen County, MN, Marshall County, MN, Norman County, MN, Pennington County, MN, Polk County, MN, Red Lake County, MN, Roseau County, MN, Adams County, ND, Barnes County, ND, Benson County, ND, Billings County, ND, Bowman County, ND, Burleigh County, ND, Cass County, ND, Dickey County, ND, Dunn County, ND, Eddy County, ND, Emmons County, ND, Foster County, ND, Golden Valley County, ND, Grand Forks County, ND, Grant County, ND, Griggs County, ND, Hettinger County, ND, Kidder County, ND, LaMoure County, ND, Logan County, ND, McIntosh County, ND, Mercer County, ND, Morton County, ND, Nelson County, ND, Oliver County, ND, Ransom County, ND, Sheridan County, ND, Sioux County, ND, Slope County, ND, Stark County, ND, Steele County, ND, Stutsman County, ND, Traill County, ND, Walsh County, ND, Wells County, ND, Butte County, SD, Campbell County, SD, Corson County, SD, Harding County, SD, Perkins County, SD

The radar

The Bismarck radar (KBIS), 17 km from the middle of the area, began a volume at 06:35 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.

Warnings issued inside it

6 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
May 21, 1:40 AM CDT	Severe Thunderstorm Warning	BIS	Stark	68 min
May 21, 2:04 AM CDT	Flash Flood Warning	BIS	Billings, Dunn, Golden Valley, McKenzie, McLean, Mercer and 4 more	6 hr
May 21, 2:05 AM CDT	Severe Thunderstorm Warning	BIS	Morton, Oliver	59 min
May 21, 2:12 AM CDT	Severe Thunderstorm Warning	BIS	Billings, Slope	56 min
May 21, 5:36 AM CDT	Severe Thunderstorm Warning	FGF	Eddy, Nelson	39 min
May 21, 5:52 AM CDT	Severe Thunderstorm Warning	FGF	Griggs	38 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, 6.6 hours before the alert went out and 14 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 665 J/kg
Mixed-layer CIN: -54 J/kg
Mixed-layer LCL: 2075 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 12 m²/s²
0-3 km storm-relative helicity: 83 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.7

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 20, 11:37 PM CDT	Mesoscale Discussion	SPC	Clay, Mahnomen, Norman, Pennington, Polk, Red Lake and 1 more	83 min
May 21, 1:08 AM CDT	Mesoscale Discussion	SPC	Big Stone, Clay, Grant, Lac qui Parle, Stevens, Traverse and 1 more	97 min
May 21, 4:52 AM CDT	Mesoscale Discussion	SPC	Becker, Clay, Mahnomen, Marshall, Norman, Pennington and 3 more	83 min
May 21, 7:43 AM CDT	Mesoscale Discussion	SPC	Becker, Clay, Mahnomen, Marshall, Norman, Pennington and 3 more	62 min
May 21, 1:24 PM CDT	Mesoscale Discussion	SPC	Becker, Clay, Clearwater, Kittson, Mahnomen, Marshall and 7 more	66 min
May 21, 3:15 PM CDT	Severe Thunderstorm Watch	SPC	Becker, Beltrami, Cass, Clay, Clearwater, Crow Wing and 13 more	6 hr
May 20, 9:30 PM CDT	Severe Thunderstorm Watch	SPC	McKenzie, Williams	5 hr
May 20, 10:45 PM CDT	Mesoscale Discussion	SPC	McKenzie, Williams	2 hr
May 21, 3:50 PM CDT	Mesoscale Discussion	SPC	Bottineau, Cavalier, McHenry, Pierce, Ramsey, Renville and 2 more	115 min
May 21, 5:00 PM CDT	Tornado Watch	SPC	Clay, Union	5 hr

Nearby

Severe Thunderstorm Watches in North Dakota, 2005 Severe Thunderstorm Watches in Minnesota, 2005 Severe Thunderstorm Watches in South Dakota, 2005 Every severe thunderstorm watch in 2005

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.