Alert archive / Wisconsin / Severe Thunderstorm Watches in 2016

Severe Thunderstorm Watch 451

August 18, 201615 counties in Wisconsin

The Storm Prediction Center issued this severe thunderstorm watch at Aug 18, 2016, 6:04 PM CDT for 15 counties in Wisconsin. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Aug 18, 2016, 6:04 PM CDT (23:04 UTC)
Expired
Aug 18, 2016, 9:40 PM CDT
In force
4 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt

Counties Adams County, WI, Columbia County, WI, Crawford County, WI, Dane County, WI, Grant County, WI, Green County, WI, Iowa County, WI, Juneau County, WI, La Crosse County, WI, Lafayette County, WI, Marquette County, WI, Monroe County, WI, Richland County, WI, Sauk County, WI, Vernon County, WI

The radar

The La Crosse radar (KARX), 79 km from the middle of the area, began a volume at 23:07 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
2%
Ten or more severe wind reports
40%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
5%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
60%

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, 11.1 hours before the alert went out and 302 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 2016-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 133 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 2016-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 67 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
133 J/kg
Mixed-layer CIN
-132 J/kg
Mixed-layer LCL
1165 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
67 m²/s²
0-3 km storm-relative helicity
109 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
Aug 18, 5:48 PM CDTMesoscale DiscussionSPCCrawford, La Crosse, Monroe, Richland, Sauk, Vernon87 min

Nearby

Severe Thunderstorm Watches in Wisconsin, 2016Every severe thunderstorm watch in 2016

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.