Alert archive / Wisconsin / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 93, NWS Milwaukee, WI

September 17, 2012Rock County, Walworth County, Wisconsin

NWS Milwaukee, WI issued this severe thunderstorm warning at Sep 17, 2012, 2:55 PM CDT for Rock County, Walworth County, Wisconsin. It was in force for 26 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Sep 17, 2012, 2:55 PM CDT (19:55 UTC)
Expired
Sep 17, 2012, 3:21 PM CDT
In force
26 min
Issued by
NWS Milwaukee, WI
Area
Storm-based polygon
Hail
1.25 in
Wind
60.0 mph

Counties Rock County, WI, Walworth County, WI

The radar

The Milwaukee radar (KMKX), 57 km from the middle of the area, began a volume at 19:59 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.

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 7.9 hours before the alert went out and 164 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 2012-09-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 452 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Davenport, at 12:00Z on 2012-09-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 15 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
452 J/kg
Mixed-layer CIN
-118 J/kg
Mixed-layer LCL
683 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
15 m²/s²
0-3 km storm-relative helicity
-13 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

673 
WUUS53 KMKX 171955
SVRMKX
WIC105-127-172100-
/O.NEW.KMKX.SV.W.0093.120917T1955Z-120917T2100Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
255 PM CDT MON SEP 17 2012

THE NATIONAL WEATHER SERVICE IN SULLIVAN HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHERN ROCK COUNTY IN SOUTH CENTRAL WISCONSIN...
  WESTERN WALWORTH COUNTY IN SOUTHEAST WISCONSIN...

* UNTIL 400 PM CDT

* AT 254 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING HALF DOLLAR SIZE HAIL...
  AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED 7
  MILES NORTHEAST OF DURAND...OR 9 MILES NORTHWEST OF ROCKTON...AND
  MOVING EAST AT 40 MPH.

* LOCATIONS IMPACTED INCLUDE...
  BELOIT...DELAVAN LAKE...WILLIAMS BAY...ELKHORN...JANESVILLE
  AIRPORT...CLINTON...SHARON...DARIEN...WALWORTH...FONTANA-ON-GENEVA
  LAKE...COMO...AFTON...SHOPIERE...TIFFANY...EMERALD GROVE...
  AVALON...ALLENS GROVE...DELAVAN...FONTANA AND ABELLS CORNERS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 60 MILES PER
HOUR...DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN. FOR
YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR
HOME OR BUSINESS. HEAVY RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE
INTO AREAS WHERE WATER COVERS THE ROAD.

&&

LAT...LON 4250 8932 4255 8934 4276 8847 4249 8843
TIME...MOT...LOC 1955Z 251DEG 35KT 4251 8921
WIND...HAIL 60MPH 1.25IN

$$
COLLAR
2 follow-up statements
807 
WWUS53 KMKX 172003
SVSMKX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
303 PM CDT MON SEP 17 2012

WIC105-127-172100-
/O.CON.KMKX.SV.W.0093.000000T0000Z-120917T2100Z/
WALWORTH WI-ROCK WI-
303 PM CDT MON SEP 17 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR SOUTHERN ROCK
AND WESTERN WALWORTH COUNTIES UNTIL 400 PM CDT...

AT 259 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING HALF DOLLAR SIZE HAIL...AND
DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED 7 MILES
NORTHWEST OF ROCKTON...MOVING EAST AT 30 MPH.

LOCATIONS IMPACTED INCLUDE...
  BELOIT...DELAVAN LAKE...WILLIAMS BAY...ELKHORN...JANESVILLE
  AIRPORT...CLINTON...SHARON...DARIEN...WALWORTH...FONTANA-ON-GENEVA
  LAKE...COMO...AFTON...SHOPIERE...TIFFANY...EMERALD GROVE...
  AVALON...ALLENS GROVE...DELAVAN...FONTANA AND ABELLS CORNERS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 60 MILES PER
HOUR...DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN. FOR
YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR
HOME OR BUSINESS. HEAVY RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE
INTO AREAS WHERE WATER COVERS THE ROAD.

&&

LAT...LON 4250 8932 4255 8934 4276 8847 4249 8843
TIME...MOT...LOC 2003Z 259DEG 25KT 4251 8915
WIND...HAIL 60MPH 1.25IN

$$
COLLAR
301 
WWUS53 KMKX 172021
SVSMKX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
321 PM CDT MON SEP 17 2012

WIC105-127-172031-
/O.CAN.KMKX.SV.W.0093.000000T0000Z-120917T2100Z/
WALWORTH WI-ROCK WI-
321 PM CDT MON SEP 17 2012

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN ROCK AND WESTERN
WALWORTH COUNTIES IS CANCELLED...

THE STORM WHICH PROMPTED THE WARNING HAS WEAKENED BELOW SEVERE
LIMITS...AND NO LONGER POSES AN IMMEDIATE THREAT TO LIFE OR PROPERTY.
 HOWEVER GUSTY WINDS AND HEAVY RAIN ARE STILL POSSIBLE WITH THIS
THUNDERSTORM.

LAT...LON 4250 8932 4255 8934 4276 8847 4249 8843
TIME...MOT...LOC 2021Z 259DEG 25KT 4253 8898

$$
COLLAR

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 17, 3:46 AM CDTSmall Craft AdvisoryMKX42 hr
Sep 17, 2:58 PM CDTSevere Thunderstorm WarningMKXMilwaukee, Waukesha62 min
Sep 17, 3:06 PM CDTSpecial Marine WarningMKX84 min

Nearby

Severe Thunderstorm Warnings in Wisconsin, 2012Every severe thunderstorm warning 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.