Alert archive / Minnesota / Severe Thunderstorm Watches in 2011

Severe Thunderstorm Watch 118

April 9, 201139 counties in Minnesota; 9 counties in Wisconsin

The Storm Prediction Center issued this severe thunderstorm watch at Apr 9, 2011, 7:42 PM CDT for 39 counties in Minnesota; 9 counties in Wisconsin. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Apr 9, 2011, 7:42 PM CDT (00:42 UTC)
Expired
Apr 10, 2011, 3:00 AM CDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
50 kt
All 48 counties

Anoka County, MN, Blue Earth County, MN, Brown County, MN, Carver County, MN, Cottonwood County, MN, Dakota County, MN, Dodge County, MN, Faribault County, MN, Fillmore County, MN, Freeborn County, MN, Goodhue County, MN, Hennepin County, MN, Houston County, MN, Jackson County, MN, Le Sueur County, MN, Lincoln County, MN, Lyon County, MN, Martin County, MN, McLeod County, MN, Mower County, MN, Murray County, MN, Nicollet County, MN, Nobles County, MN, Olmsted County, MN, Pipestone County, MN, Ramsey County, MN, Redwood County, MN, Renville County, MN, Rice County, MN, Rock County, MN, Scott County, MN, Sibley County, MN, Steele County, MN, Wabasha County, MN, Waseca County, MN, Washington County, MN, Watonwan County, MN, Winona County, MN, Yellow Medicine County, MN, Buffalo County, WI, Chippewa County, WI, Dunn County, WI, Eau Claire County, WI, La Crosse County, WI, Pepin County, WI, Pierce County, WI, Saint Croix County, WI, Trempealeau County, WI

The radar

The Minneapolis radar (KMPX), 113 km from the middle of the area, began a volume at 00:43 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
10%
One or more EF2 to EF5 tornadoes
5%
Ten or more severe wind reports
20%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
90%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
95%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 9, 8:55 PM CDTSevere Thunderstorm WarningFSDLincoln, Lyon, Murray, Pipestone50 min
Apr 9, 8:59 PM CDTSevere Thunderstorm WarningMPXRedwood46 min
Apr 9, 9:17 PM CDTSevere Thunderstorm WarningFSDPipestone, Rock43 min
Apr 9, 9:45 PM CDTSevere Thunderstorm WarningFSDLyon30 min
Apr 9, 9:54 PM CDTSevere Thunderstorm WarningFSDMurray, Nobles, Pipestone, Rock51 min
Apr 9, 11:08 PM CDTSevere Thunderstorm WarningARXMower52 min
Apr 9, 11:15 PM CDTSevere Thunderstorm WarningARXFillmore45 min
Apr 9, 11:16 PM CDTSevere Thunderstorm WarningFSDJackson, Nobles21 min
Apr 10, 12:39 AM CDTSevere Thunderstorm WarningMPXFreeborn34 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

Minneapolis, MN (KMPX), launched 00:00Z, 0.7 hours before the alert went out and 110 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-pSkew-T log-p diagram, Minneapolis, MN at 00:00Z on 2011-04-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Minneapolis, MN at 00:00Z on 2011-04-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 355 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
612 m above ground
0-6 km bulk shear
54 kt
0-1 km storm-relative helicity
355 m²/s²
0-3 km storm-relative helicity
550 m²/s²
Significant tornado parameter
0.0
Supercell composite
5.2

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 9, 7:47 PM CDTSevere Thunderstorm WatchSPCCottonwood, Jackson, Lincoln, Lyon, Murray, Nobles and 2 more3 hr
Apr 9, 10:43 PM CDTMesoscale DiscussionSPCFillmore, Houston62 min
Apr 9, 11:01 PM CDTTornado WatchSPCFillmore, Houston, Mower5 hr
Apr 10, 1:26 AM CDTMesoscale DiscussionSPCBlue Earth, Brown, Cottonwood, Dakota, Dodge, Faribault and 19 more64 min
Apr 10, 1:30 PM CDTMesoscale DiscussionSPCChisago, Fillmore, Houston, Olmsted, Wabasha, Winona2 hr
Apr 10, 3:19 PM CDTTornado Watch PDSSPCFillmore, Houston, Olmsted, Wabasha, Winona7 hr
Apr 9, 9:06 PM CDTMesoscale DiscussionSPCClay, Lincoln, Union54 min
Apr 10, 6:02 PM CDTMesoscale DiscussionSPCAdams, Brown, Calumet, Columbia, Dane, Dodge and 26 more88 min

Nearby

Severe Thunderstorm Watches in Minnesota, 2011Severe Thunderstorm Watches in Wisconsin, 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.