Alert archive / Minnesota / Severe Thunderstorm Watches in 2012

Severe Thunderstorm Watch 476

July 6, 201228 counties in Minnesota; 23 counties in Wisconsin

The Storm Prediction Center issued this severe thunderstorm watch at Jul 6, 2012, 6:39 PM CDT for 28 counties in Minnesota; 23 counties in Wisconsin. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Jul 6, 2012, 6:39 PM CDT (23:39 UTC)
Expired
Jul 7, 2012, 2:00 AM CDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 51 counties

Anoka County, MN, Blue Earth County, MN, Brown County, MN, Carver County, MN, Chisago County, MN, Dakota County, MN, Dodge County, MN, Goodhue County, MN, Hennepin County, MN, Isanti County, MN, Le Sueur County, MN, McLeod County, MN, Nicollet County, MN, Olmsted County, MN, Ramsey County, MN, Redwood County, MN, Renville County, MN, Rice County, MN, Scott County, MN, Sherburne County, MN, Sibley County, MN, Steele County, MN, Wabasha County, MN, Waseca County, MN, Washington County, MN, Watonwan County, MN, Winona County, MN, Wright County, MN, Barron County, WI, Buffalo County, WI, Chippewa County, WI, Clark County, WI, Dunn County, WI, Eau Claire County, WI, Forest County, WI, Jackson County, WI, Langlade County, WI, Lincoln County, WI, Marathon County, WI, Oneida County, WI, Pepin County, WI, Pierce County, WI, Polk County, WI, Price County, WI, Rusk County, WI, Saint Croix County, WI, Sawyer County, WI, Taylor County, WI, Trempealeau County, WI, Washburn County, WI, Wood County, WI

The radar

The Minneapolis radar (KMPX), 153 km from the middle of the area, began a volume at 23:43 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
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
50%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
80%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jul 6, 6:40 PM CDTSevere Thunderstorm WarningMPXSaint Croix65 min
Jul 6, 6:48 PM CDTSevere Thunderstorm WarningMPXBarron, Rusk42 min
Jul 6, 6:52 PM CDTSevere Thunderstorm WarningMPXCarver, Scott, Sibley23 min
Jul 6, 7:05 PM CDTSevere Thunderstorm WarningGRBOneida, Vilas40 min
Jul 6, 7:40 PM CDTTornado WarningGRBOneida35 min
Jul 6, 8:04 PM CDTSevere Thunderstorm WarningDLHSawyer13 min
Jul 6, 9:11 PM CDTSevere Thunderstorm WarningGRBForest, Oneida, Vilas35 min
Jul 6, 9:39 PM CDTSevere Thunderstorm WarningMPXMeeker, Wright36 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 12:00Z, 11.7 hours before the alert went out and 156 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 12:00Z on 2012-07-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2912 joules per kilogram.LCLLFCEL10008507005003002001001 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 12:00Z on 2012-07-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 120 square meters per square second.1939Sfc1 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
2912 J/kg
Mixed-layer CIN
-98 J/kg
Mixed-layer LCL
925 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
120 m²/s²
0-3 km storm-relative helicity
137 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 6, 6:02 PM CDTMesoscale DiscussionSPCAnoka, Benton, Brown, Carlton, Carver, Chippewa and 32 more28 min

Nearby

Severe Thunderstorm Watches in Minnesota, 2012Severe Thunderstorm Watches in Wisconsin, 2012Every 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.