Alert archive / Wisconsin / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 116, NWS Milwaukee, WI

July 21, 1998Rock County, Walworth County, Wisconsin

NWS Milwaukee, WI issued this severe thunderstorm warning at Jul 21, 1998, 1:01 PM CDT for Rock County, Walworth County, Wisconsin. It was in force for 64 min. 3 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Jul 21, 1998, 1:01 PM CDT (18:01 UTC)
Expired
Jul 21, 1998, 2:05 PM CDT
In force
64 min
Issued by
NWS Milwaukee, WI
Area
Whole counties

Counties Rock County, WI, Walworth County, WI

The radar

The Milwaukee radar (KMKX), 39 km from the middle of the area, began a volume at 18:01 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 was reported inside it

TimeReportWhereRemark
Jul 21, 1:10 PM CDTThunderstorm Wind 87Elkhorn, WI
Jul 21, 1:20 PM CDTThunderstorm WindBeloit, WI
Jul 21, 1:20 PM CDTThunderstorm WindSharon, WI

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The nearest sounding before it

Green Bay/Straub, WI (KGRB), launched 12:00Z, 6.0 hours before the alert went out and 209 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 1998-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2271 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 1998-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 155 square meters per square second.193958Sfc1 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
2271 J/kg
Mixed-layer CIN
-168 J/kg
Mixed-layer LCL
608 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
155 m²/s²
0-3 km storm-relative helicity
185 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

In the hours before

Special weather statement, Jul 21, 11:00 AM CDT, 2 hours 1 minute before
WIZ046-047-051-052-056>060-062>072-220200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
11 AM CDT TUE JUL 21 1998

...SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND TONIGHT...
...FOR SOUTH CENTRAL AND SOUTHEAST WISCONSIN...

THREAT...DAMAGING WINDS...LARGE HAIL...HEAVY RAINFALL

DISCUSSION...
A CLUSTER OF STRONG THUNDERSTORMS MOVING INTO SOUTHWEST WISCONSIN
MAY INTENSIFY AS THEY MOVE INTO THE VERY UNSTABLE AIRp OVER THE SOUTHERN
THIRD OF THE STATE. ENOUGH MOISTURE IS AVAILABLE TO THE STORMS TO
PRODUCE LOCALIZED FLOODING FROM HEAVY RAINFALL.

SPOTTER ACTION...
STORM SPOTTER GROUPS MAY NEED TO BE ACTIVATED THIS AFTERNOON AND INTO
TONIGHT.

GARCIA
Special weather statement, Jul 21, 11:00 AM CDT, 2 hours 1 minute before
WIZ046-047-051-052-056>060-062>072-220200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
11 AM CDT TUE JUL 21 1998

...SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND TONIGHT...
...FOR SOUTH CENTRAL AND SOUTHEAST WISCONSIN...

THREAT...DAMAGING WINDS...LARGE HAIL...HEAVY RAINFALL

DISCUSSION...
A CLUSTER OF STRONG THUNDERSTORMS MOVING INTO SOUTHWEST WISCONSIN
MAY INTENSIFY AS THEY MOVE INTO THE VERY UNSTABLE AIRp OVER THE SOUTHERN
THIRD OF THE STATE. ENOUGH MOISTURE IS AVAILABLE TO THE STORMS TO
PRODUCE LOCALIZED FLOODING FROM HEAVY RAINFALL.

SPOTTER ACTION...
STORM SPOTTER GROUPS MAY NEED TO BE ACTIVATED THIS AFTERNOON AND INTO
TONIGHT.

GARCIA

The office that day

Everything else NWS Milwaukee, WI issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 20, 10:22 PM CDTSevere Thunderstorm WarningMKXGreen Lake53 min
Jul 20, 10:39 PM CDTSevere Thunderstorm WarningMKXFond du Lac, Green Lake61 min
Jul 20, 11:21 PM CDTSevere Thunderstorm WarningMKXDodge64 min
Jul 20, 11:49 PM CDTSevere Thunderstorm WarningMKXWashington61 min
Jul 21, 12:18 AM CDTSevere Thunderstorm WarningMKXOzaukee42 min
Jul 21, 1:32 PM CDTSevere Thunderstorm WarningMKXKenosha, Racine63 min

Nearby

Severe Thunderstorm Warnings in Wisconsin, 1998Every severe thunderstorm warning in 1998

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.