Alert archive / Minnesota / Severe Thunderstorm Watches in 2012

Severe Thunderstorm Watch 225

May 2, 201220 counties in Minnesota

The Storm Prediction Center issued this severe thunderstorm watch at May 2, 2012, 5:25 PM CDT for 20 counties in Minnesota. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued: May 2, 2012, 5:25 PM CDT (22:25 UTC)
Expired: May 2, 2012, 9:43 PM CDT
In force: 4 hr
Issued by: the Storm Prediction Center
Largest hail expected: 2 in
Strongest gust expected: 60 kt

Counties Blue Earth County, MN, Brown County, MN, Cottonwood County, MN, Dodge County, MN, Faribault County, MN, Freeborn County, MN, Goodhue County, MN, Jackson County, MN, Le Sueur County, MN, Martin County, MN, Mower County, MN, Murray County, MN, Nicollet County, MN, Nobles County, MN, Olmsted County, MN, Rice County, MN, Steele County, MN, Wabasha County, MN, Waseca County, MN, Watonwan County, MN

The radar

The Minneapolis radar (KMPX), 96 km from the middle of the area, began a volume at 22:28 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: 30%
One or more gusts of 65 knots or more: 20%
Ten or more severe hail reports: 40%
One or more hailstones of 2 inches or more: 30%
Six or more combined severe hail and wind reports: 70%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
May 2, 5:50 PM CDT	Tornado Warning	MPX	Blue Earth, Brown, Nicollet, Watonwan	40 min
May 2, 6:20 PM CDT	Severe Thunderstorm Warning	MPX	Blue Earth, Le Sueur, Nicollet, Waseca	55 min
May 2, 6:45 PM CDT	Severe Thunderstorm Warning	MPX	Goodhue, Rice, Steele	60 min
May 2, 6:45 PM CDT	Severe Thunderstorm Warning	MPX	Brown, Redwood	60 min
May 2, 6:47 PM CDT	Severe Thunderstorm Warning	ARX	Dodge	28 min
May 2, 6:58 PM CDT	Severe Thunderstorm Warning	MPX	Le Sueur, Rice, Steele, Waseca	47 min
May 2, 7:12 PM CDT	Severe Thunderstorm Warning	MPX	Brown	63 min
May 2, 7:29 PM CDT	Severe Thunderstorm Warning	ARX	Wabasha, Winona	38 min
May 2, 7:29 PM CDT	Severe Thunderstorm Warning	MPX	Goodhue	61 min
May 2, 7:30 PM CDT	Severe Thunderstorm Warning	MPX	Goodhue, Rice, Steele	60 min
May 2, 7:32 PM CDT	Tornado Warning	MPX	Rice, Steele, Waseca	28 min
May 2, 8:10 PM CDT	Severe Thunderstorm Warning	ARX	Wabasha	65 min
May 2, 8:22 PM CDT	Flash Flood Warning	MPX	Goodhue	3 hr
May 2, 8:27 PM CDT	Severe Thunderstorm Warning	MPX	Goodhue	33 min
May 2, 8:46 PM CDT	Severe Thunderstorm Warning	MPX	Goodhue	29 min
May 2, 8:48 PM CDT	Severe Thunderstorm Warning	ARX	Wabasha	72 min
May 2, 8:51 PM CDT	Flash Flood Warning	ARX	Wabasha	6 hr
May 2, 9:13 PM CDT	Severe Thunderstorm Warning	ARX	Wabasha	17 min
May 2, 9:19 PM CDT	Severe Thunderstorm Warning	ARX	Wabasha, Winona	56 min
May 2, 9:33 PM CDT	Tornado Warning	ARX	Wabasha	27 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

Omaha, NE (KOAX), launched 12:00Z, 10.4 hours before the alert went out and 358 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: 2537 J/kg
Mixed-layer CIN: -61 J/kg
Mixed-layer LCL: 500 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 41 m²/s²
0-3 km storm-relative helicity: 100 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.6

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 1, 9:18 PM CDT	Severe Thunderstorm Watch	SPC	Cottonwood, Jackson	7 hr
May 1, 10:48 PM CDT	Mesoscale Discussion	SPC	Blue Earth, Dakota, Dodge, Faribault, Fillmore, Freeborn and 9 more	87 min
May 2, 3:34 PM CDT	Mesoscale Discussion	SPC	Blue Earth, Brown, Cottonwood, Dodge, Faribault, Freeborn and 16 more	86 min

Nearby

Severe Thunderstorm Watches in Minnesota, 2012 Every severe thunderstorm watch in 2012

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.