Alert archive / Wisconsin / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 104, NWS Milwaukee, WI

July 20, 1998Iowa County, Sauk County, Wisconsin

NWS Milwaukee, WI issued this severe thunderstorm warning at Jul 20, 1998, 5:18 PM CDT for Iowa County, Sauk County, Wisconsin. It was in force for 72 min. 2 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 20, 1998, 5:18 PM CDT (22:18 UTC)
Expired
Jul 20, 1998, 6:30 PM CDT
In force
72 min
Issued by
NWS Milwaukee, WI
Area
Whole counties

Counties Iowa County, WI, Sauk County, WI

What was reported inside it

TimeReportWhereRemark
Jul 20, 5:40 PM CDTThunderstorm WindPlain, WI
Jul 20, 6:10 PM CDTThunderstorm WindLake Delton, 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jul 20, 4:00 PM CDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 10.3 hours before the alert went out and 181 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, Davenport, at 12:00Z on 1998-07-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1102 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, Davenport, at 12:00Z on 1998-07-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 9 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
1102 J/kg
Mixed-layer CIN
-200 J/kg
Mixed-layer LCL
1216 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
9 m²/s²
0-3 km storm-relative helicity
95 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

044 
WUUS1 KMKE 202220 RRA
SVRMKE
WIC049-111-202330-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
518 PM CDT MON JUL 20 1998

THE NATIONAL WEATHER SERVICE IN MILWAUKEE/SULLIVAN WI HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  IOWA COUNTY IN SOUTH CENTRAL WISCONSIN
  SAUK COUNTY IN SOUTH CENTRAL WISCONSIN

* UNTIL 630 PM CDT

* AT 515 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  A LINE OF SEVERE THUNDERSTORMS EXTENDING FROM VIROQUA IN VERNON
  COUNTY TO STEUBEN IN CRAWFORD COUNTY... MOVING SOUTHEAST AT 40
  MPH.

THE LINE OF SEVERE THUNDERSTORMS HAS PRODUCED HURRICANE WINDS OF
92 MPH IN MOUNT STERLING IN CRAWFORD COUNTY

IF YOU ARE IN THESE AREAS... SEEK SAFETY IN A SMALL INTERIOR ROOM
AWAY FROM WINDOWS. A BASEMENT OFFERS THE BEST PROTECTION. SEVERE
THUNDERSTORMS WILL OCCASIONALLY PRODUCE TORNADOES.

JH/KRR

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 20, 12:30 PM CDT, 4 hours 48 minutes before
WIZ046-047-051-052-056>060-062>072-211000-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1230 PM CDT MON JUL 20 1998

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

THREAT...DAMAGING WINDS AND LARGE HAIL

DISCUSSION...
A WARM FRONT LIFTING NORTH FROM IOWA IS EXPECTED TO INTERACT WITH A
FAST WEST-EAST JET STREAM ALOFT AND A COOL FRONT TO PRODUCE A LINE
OF STRONG TO SEVERE THUNDERSTORMS TONIGHT.

SPOTTER ACTION...
STORM SPOTTER GROUPS MAY NEED TO BE ACTIVATED TOWARDS EVENING AND
DURING THE OVERNIGHT HOURS.
Special weather statement, Jul 20, 12:30 PM CDT, 4 hours 48 minutes before
WIZ046-047-051-052-056>060-062>072-211000-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1230 PM CDT MON JUL 20 1998

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

THREAT...DAMAGING WINDS AND LARGE HAIL

DISCUSSION...
A WARM FRONT LIFTING NORTH FROM IOWA IS EXPECTED TO INTERACT WITH A
FAST WEST-EAST JET STREAM ALOFT AND A COOL FRONT TO PRODUCE A LINE
OF STRONG TO SEVERE THUNDERSTORMS TONIGHT.

SPOTTER ACTION...
STORM SPOTTER GROUPS MAY NEED TO BE ACTIVATED TOWARDS EVENING AND
DURING THE OVERNIGHT HOURS.

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 20, 5:55 PM CDTSevere Thunderstorm WarningMKXDane65 min
Jul 20, 5:55 PM CDTSevere Thunderstorm WarningMKXLafayette65 min
Jul 20, 6:29 PM CDTSevere Thunderstorm WarningMKXJefferson, Waukesha61 min
Jul 20, 6:33 PM CDTSevere Thunderstorm WarningMKXRock62 min
Jul 20, 6:42 PM CDTSevere Thunderstorm WarningMKXMilwaukee48 min
Jul 20, 6:48 PM CDTSevere Thunderstorm WarningMKXKenosha, Racine, Walworth72 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.