Alert archive / Wisconsin / Severe Thunderstorm Watches in 2011

Severe Thunderstorm Watch 680

July 23, 201125 counties in Wisconsin

The Storm Prediction Center issued this severe thunderstorm watch at Jul 23, 2011, 6:36 PM CDT for 25 counties in Wisconsin. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Jul 23, 2011, 6:36 PM CDT (23:36 UTC)
Expired
Jul 24, 2011, 2:00 AM CDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt
All 25 counties

Adams County, WI, Clark County, WI, Columbia County, WI, Dane County, WI, Dodge County, WI, Fond du Lac County, WI, Green Lake County, WI, Jackson County, WI, Jefferson County, WI, Juneau County, WI, La Crosse County, WI, Marquette County, WI, Milwaukee County, WI, Monroe County, WI, Ozaukee County, WI, Richland County, WI, Sauk County, WI, Sheboygan County, WI, Trempealeau County, WI, Vernon County, WI, Washington County, WI, Waukesha County, WI, Waushara County, WI, Winnebago County, WI, Wood County, WI

The radar

The La Crosse radar (KARX), 83 km from the middle of the area, began a volume at 23:37 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
30%
One or more gusts of 65 knots or more
5%
Ten or more severe hail reports
20%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
60%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jul 23, 9:18 PM CDTSevere Thunderstorm WarningMKXDodge35 min
Jul 23, 11:53 PM CDTSevere Thunderstorm WarningARXClark53 min
Jul 24, 12:37 AM CDTSevere Thunderstorm WarningARXClark, Jackson, Monroe, Trempealeau38 min
Jul 24, 1:14 AM CDTSevere Thunderstorm WarningARXAdams, Jackson, Juneau, La Crosse, Monroe61 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, 11.6 hours before the alert went out and 175 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 2011-07-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2346 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 2011-07-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -42 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
2346 J/kg
Mixed-layer CIN
-15 J/kg
Mixed-layer LCL
615 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
-42 m²/s²
0-3 km storm-relative helicity
-11 m²/s²
Significant tornado parameter
-0.3
Supercell composite
-1.9

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 22, 7:38 PM CDTMesoscale DiscussionSPCGrant, Green, Lafayette97 min
Jul 23, 4:38 AM CDTMesoscale DiscussionSPCBurnett, Polk67 min
Jul 23, 9:37 AM CDTMesoscale DiscussionSPCAdams, Brown, Buffalo, Calumet, Chippewa, Clark and 25 more53 min
Jul 23, 10:14 AM CDTSevere Thunderstorm WatchSPCAdams, Buffalo, Crawford, Jackson, Juneau, La Crosse and 4 more4 hr
Jul 23, 1:10 PM CDTMesoscale DiscussionSPCCrawford, Jackson, Juneau, La Crosse, Monroe, Richland and 1 more65 min
Jul 23, 5:26 PM CDTMesoscale DiscussionSPCAdams, Clark, Eau Claire, Jackson, Juneau, Marathon and 9 more64 min

Nearby

Severe 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.