Alert archive / Wisconsin / Severe Thunderstorm Watches in 2012

Severe Thunderstorm Watch 614

September 4, 20124 states

The Storm Prediction Center issued this severe thunderstorm watch at Sep 4, 2012, 3:27 PM CDT for 4 states. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued
Sep 4, 2012, 3:27 PM CDT (20:27 UTC)
Expired
Sep 4, 2012, 11:00 PM CDT
In force
8 hr
Issued by
the Storm Prediction Center
Largest hail expected
2.5 in
Strongest gust expected
60 kt
All 91 counties

Allamakee County, IA, Black Hawk County, IA, Bremer County, IA, Buchanan County, IA, Butler County, IA, Chickasaw County, IA, Clayton County, IA, Delaware County, IA, Dubuque County, IA, Fayette County, IA, Floyd County, IA, Grundy County, IA, Howard County, IA, Mitchell County, IA, Winneshiek County, IA, Gogebic County, MI, Ontonagon County, MI, Carlton County, MN, Cook County, MN, Dodge County, MN, Fillmore County, MN, Goodhue County, MN, Houston County, MN, Itasca County, MN, Koochiching County, MN, Lake County, MN, Mower County, MN, Olmsted County, MN, Pine County, MN, Saint Louis County, MN, Wabasha County, MN, Winona County, MN, Adams County, WI, Ashland County, WI, Barron County, WI, Bayfield County, WI, Brown County, WI, Buffalo County, WI, Burnett County, WI, Calumet County, WI, Chippewa County, WI, Clark County, WI, Columbia County, WI, Crawford County, WI, Dane County, WI, Dodge County, WI, Douglas County, WI, Dunn County, WI, Eau Claire County, WI, Grant County, WI, Green County, WI, Iowa County, WI, Iron County, WI, Jackson County, WI, Jefferson County, WI, Juneau County, WI, Kenosha County, WI, La Crosse County, WI, Lafayette County, WI, Lincoln County, WI, Marathon County, WI, Milwaukee County, WI, Monroe County, WI, Oneida County, WI, Outagamie County, WI, Ozaukee County, WI, Pepin County, WI, Pierce County, WI, Polk County, WI, Portage County, WI, Price County, WI, Racine County, WI, Richland County, WI, Rock County, WI, Rusk County, WI, Saint Croix County, WI, Sauk County, WI, Sawyer County, WI, Shawano County, WI, Taylor County, WI, Trempealeau County, WI, Vernon County, WI, Vilas County, WI, Walworth County, WI, Washburn County, WI, Washington County, WI, Waukesha County, WI, Waupaca County, WI, Waushara County, WI, Winnebago County, WI, Wood County, WI

The radar

The Duluth radar (KDLH), 123 km from the middle of the area, began a volume at 20:29 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
2%
Ten or more severe wind reports
50%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
70%
One or more hailstones of 2 inches or more
40%
Six or more combined severe hail and wind reports
95%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Sep 4, 3:48 PM CDTSevere Thunderstorm WarningDLHSaint Louis42 min
Sep 4, 4:00 PM CDTSevere Thunderstorm WarningARXWinona30 min
Sep 4, 4:17 PM CDTSevere Thunderstorm WarningMPXBarron, Chippewa, Rusk43 min
Sep 4, 4:29 PM CDTSevere Thunderstorm WarningARXWinona46 min
Sep 4, 4:29 PM CDTSevere Thunderstorm WarningDLHLake, Saint Louis46 min
Sep 4, 4:39 PM CDTSevere Thunderstorm WarningDLHAshland, Bayfield36 min
Sep 4, 4:55 PM CDTSevere Thunderstorm WarningMPXChippewa50 min
Sep 4, 5:06 PM CDTSevere Thunderstorm WarningMPXEau Claire39 min
Sep 4, 5:14 PM CDTSevere Thunderstorm WarningDLHCook, Lake, Saint Louis31 min
Sep 4, 5:17 PM CDTSevere Thunderstorm WarningARXAllamakee28 min
Sep 4, 5:19 PM CDTSevere Thunderstorm WarningMPXEau Claire26 min
Sep 4, 5:29 PM CDTSevere Thunderstorm WarningARXHouston, Winona46 min
Sep 4, 5:38 PM CDTSevere Thunderstorm WarningARXFillmore28 min
Sep 4, 5:39 PM CDTSevere Thunderstorm WarningMPXChippewa, Eau Claire36 min
Sep 4, 5:41 PM CDTSevere Thunderstorm WarningARXClark64 min
Sep 4, 5:50 PM CDTSevere Thunderstorm WarningARXHouston40 min
Sep 4, 5:56 PM CDTSevere Thunderstorm WarningARXLa Crosse, Vernon64 min
Sep 4, 6:09 PM CDTSevere Thunderstorm WarningARXAllamakee, Clayton36 min
Sep 4, 6:11 PM CDTSevere Thunderstorm WarningMPXEau Claire30 min
Sep 4, 6:14 PM CDTSevere Thunderstorm WarningARXHouston46 min
Sep 4, 6:16 PM CDTSevere Thunderstorm WarningARXClark29 min
Sep 4, 6:26 PM CDTSevere Thunderstorm WarningGRBMarathon, Wood36 min
Sep 4, 6:37 PM CDTSevere Thunderstorm WarningARXAllamakee, Clayton38 min
Sep 4, 6:38 PM CDTSevere Thunderstorm WarningARXAllamakee52 min
Sep 4, 6:48 PM CDTSevere Thunderstorm WarningARXCrawford, Vernon57 min
Sep 4, 6:59 PM CDTSevere Thunderstorm WarningGRBMarathon, Portage, Wood46 min
Sep 4, 7:00 PM CDTSevere Thunderstorm WarningARXGrant60 min
Sep 4, 7:06 PM CDTSevere Thunderstorm WarningARXAllamakee24 min
Sep 4, 7:10 PM CDTSevere Thunderstorm WarningARXRichland65 min
Sep 4, 7:20 PM CDTSevere Thunderstorm WarningMKXIowa, Sauk55 min
Sep 4, 7:35 PM CDTSevere Thunderstorm WarningARXClayton70 min
Sep 4, 7:40 PM CDTSevere Thunderstorm WarningGRBMarathon, Portage, Shawano, Waupaca, Waushara39 min
Sep 4, 7:41 PM CDTTornado WarningARXGrant34 min
Sep 4, 7:42 PM CDTSevere Thunderstorm WarningMQTOntonagon63 min
Sep 4, 7:46 PM CDTSevere Thunderstorm WarningMKXDane, Iowa, Sauk59 min
Sep 4, 7:48 PM CDTSevere Thunderstorm WarningMKXColumbia, Dane, Sauk42 min
Sep 4, 8:09 PM CDTFlash Flood WarningARXAllamakee, Clayton6 hr
Sep 4, 8:12 PM CDTSevere Thunderstorm WarningMKXColumbia, Dane, Dodge, Green, Jefferson, Rock63 min
Sep 4, 8:16 PM CDTSevere Thunderstorm WarningGRBOutagamie, Shawano, Waupaca35 min
Sep 4, 8:16 PM CDTSevere Thunderstorm WarningMKXGreen, Iowa, Lafayette59 min
Sep 4, 8:35 PM CDTSevere Thunderstorm WarningMKXDodge, Jefferson, Rock, Walworth, Washington, Waukesha55 min
Sep 4, 8:51 PM CDTSevere Thunderstorm WarningARXGrant39 min
Sep 4, 9:07 PM CDTSevere Thunderstorm WarningMKXKenosha, Milwaukee, Ozaukee, Racine, Walworth, Washington and 1 more83 min
Sep 4, 10:10 PM CDTSevere Thunderstorm WarningARXClayton, Fayette65 min
Sep 4, 10:42 PM CDTSevere Thunderstorm WarningARXAllamakee, Winneshiek33 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, 8.5 hours before the alert went out and 186 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 2012-09-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1446 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 2012-09-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 172 square meters per square second.19395878Sfc1 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
1446 J/kg
Mixed-layer CIN
-171 J/kg
Mixed-layer LCL
1471 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
172 m²/s²
0-3 km storm-relative helicity
221 m²/s²
Significant tornado parameter
0.0
Supercell composite
7.8

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 4, 1:33 PM CDTMesoscale DiscussionSPCAllamakee, Bremer, Chickasaw, Clayton, Delaware, Fayette and 2 more117 min
Sep 4, 5:08 PM CDTMesoscale DiscussionSPCHarrison, Monona97 min
Sep 4, 6:39 PM CDTMesoscale DiscussionSPCAllamakee, Black Hawk, Bremer, Buchanan, Butler, Chickasaw and 9 more66 min

Nearby

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