Alert archive / Wisconsin / Severe Thunderstorm Watches in 2012

Severe Thunderstorm Watch 230

May 3, 201211 counties in Illinois; 13 counties in Wisconsin

The Storm Prediction Center issued this severe thunderstorm watch at May 3, 2012, 1:07 PM CDT for 11 counties in Illinois; 13 counties in Wisconsin. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
May 3, 2012, 1:07 PM CDT (18:07 UTC)
Expired
May 3, 2012, 7:00 PM CDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 24 counties

Boone County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Kane County, IL, Kendall County, IL, Lake County, IL, McHenry County, IL, Ogle County, IL, Will County, IL, Winnebago County, IL, Columbia County, WI, Dane County, WI, Dodge County, WI, Green County, WI, Jefferson County, WI, Kenosha County, WI, Milwaukee County, WI, Ozaukee County, WI, Racine County, WI, Rock County, WI, Walworth County, WI, Washington County, WI, Waukesha County, WI

The radar

The Milwaukee radar (KMKX), 25 km from the middle of the area, began a volume at 18:08 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
30%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
60%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
May 3, 1:29 PM CDTSevere Thunderstorm WarningMKXJefferson46 min
May 3, 1:41 PM CDTSevere Thunderstorm WarningMKXDodge, Washington49 min
May 3, 2:15 PM CDTSevere Thunderstorm WarningMKXMilwaukee, Ozaukee, Washington, Waukesha30 min
May 3, 2:59 PM CDTSevere Thunderstorm WarningMKXColumbia, Dodge46 min
May 3, 3:21 PM CDTSevere Thunderstorm WarningMKXDane39 min
May 3, 3:52 PM CDTSevere Thunderstorm WarningMKXDodge23 min
May 3, 3:52 PM CDTSevere Thunderstorm WarningMKXDane, Jefferson23 min
May 3, 4:10 PM CDTSevere Thunderstorm WarningMKXJefferson, Waukesha35 min
May 3, 6:20 PM CDTSevere Thunderstorm WarningLOTCook43 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

Green Bay/Straub, WI (KGRB), launched 12:00Z, 6.1 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, Green Bay/Straub, WI at 12:00Z on 2012-05-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 321 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, Green Bay/Straub, WI at 12:00Z on 2012-05-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 160 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
321 J/kg
Mixed-layer CIN
-146 J/kg
Mixed-layer LCL
565 m above ground
0-6 km bulk shear
58 kt
0-1 km storm-relative helicity
160 m²/s²
0-3 km storm-relative helicity
220 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.8

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 3, 2:53 PM CDTMesoscale DiscussionSPCBoone, Cook, DeKalb, DuPage, Kane, Lake and 3 more67 min
May 3, 3:53 PM CDTMesoscale DiscussionSPCBrown, Bureau, Cass, DeWitt, Fulton, Greene and 22 more37 min
May 3, 4:20 PM CDTTornado WatchSPCBureau, Cass, Champaign, DeWitt, Ford, Fulton and 26 more8 hr
May 3, 6:22 PM CDTMesoscale DiscussionSPCCook, DeKalb, DuPage, Kane, Kendall, Lake and 1 more23 min
May 3, 6:41 PM CDTSevere Thunderstorm WatchSPCBoone, Cook, DeKalb, DuPage, Ford, Grundy and 12 more5 hr
May 3, 6:42 PM CDTMesoscale DiscussionSPCAdams, Brown, Cass, DeWitt, Fulton, Greene and 17 more63 min
May 2, 11:51 PM CDTMesoscale DiscussionSPCManistee, Mason, Oceana54 min
May 3, 10:34 AM CDTMesoscale DiscussionSPCArenac, Bay, Clare, Clinton, Genesee, Gladwin and 28 more86 min
May 3, 11:41 AM CDTSevere Thunderstorm WatchSPCAlcona, Alpena, Antrim, Arenac, Bay, Benzie and 23 more5 hr
May 3, 1:35 PM CDTSevere Thunderstorm WatchSPCAllegan, Barry, Berrien, Branch, Calhoun, Cass and 27 more8 hr
May 3, 1:39 PM CDTMesoscale DiscussionSPCAntrim, Arenac, Bay, Benzie, Clare, Crawford and 18 more66 min
May 3, 3:33 PM CDTMesoscale DiscussionSPCAllegan, Barry, Bay, Calhoun, Cass, Clinton and 15 more57 min
May 3, 5:57 PM CDTMesoscale DiscussionSPCAllegan, Barry, Berrien, Branch, Calhoun, Cass and 28 more63 min
May 2, 7:38 PM CDTMesoscale DiscussionSPCAdams, Buffalo, Jackson, Juneau, La Crosse, Monroe and 4 more37 min
May 2, 7:47 PM CDTSevere Thunderstorm WatchSPCAdams, Buffalo, Clark, Jackson, Juneau, La Crosse and 3 more5 hr
May 3, 8:43 AM CDTMesoscale DiscussionSPCAdams, Brown, Buffalo, Calumet, Clark, Columbia and 26 more92 min

Nearby

Severe Thunderstorm Watches in Wisconsin, 2012Severe Thunderstorm Watches in Illinois, 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.