Alert archive / Wisconsin / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 155, NWS Twin Cities, MN

September 20, 20185 counties in Wisconsin

NWS Twin Cities, MN issued this severe thunderstorm warning at Sep 20, 2018, 7:37 PM CDT for 5 counties in Wisconsin. It was in force for 38 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Sep 20, 2018, 7:37 PM CDT (00:37 UTC)
Expired
Sep 20, 2018, 8:15 PM CDT
In force
38 min
Issued by
NWS Twin Cities, MN
Area
Storm-based polygon
Tornado
Possible
Hail
0.75 in
Wind
70.0 mph

Counties Chippewa County, WI, Dunn County, WI, Eau Claire County, WI, Pepin County, WI, Saint Croix County, WI

The radar

The Minneapolis radar (KMPX), 128 km from the middle of the area, began a volume at 00:36 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
Sep 20, 8:13 PM CDTTSTM WND DMGAltoona, WIMULTIPLE TREES AND POWER LINES DOWN.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

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

IssuedProductOfficeLasted
Sep 20, 6:23 PM CDTTornado WatchSPC5 hr

The nearest sounding before it

Green Bay/Straub, WI (KGRB), launched 00:00Z, 0.6 hours before the alert went out and 307 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 00:00Z on 2018-09-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3 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, Green Bay/Straub, WI at 00:00Z on 2018-09-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 340 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
3 J/kg
Mixed-layer CIN
-76 J/kg
Mixed-layer LCL
512 m above ground
0-6 km bulk shear
58 kt
0-1 km storm-relative helicity
340 m²/s²
0-3 km storm-relative helicity
454 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.5

Open this sounding in Storm Lab

The text

As transmitted.

133 
WUUS53 KMPX 210037
SVRMPX
WIC017-033-035-091-109-210115-
/O.NEW.KMPX.SV.W.0155.180921T0037Z-180921T0115Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Twin Cities/Chanhassen MN
737 PM CDT THU SEP 20 2018

The National Weather Service in The Twin Cities has issued a

* Severe Thunderstorm Warning for...
  Northeastern Pepin County in west central Wisconsin...
  Dunn County in west central Wisconsin...
  Eastern St. Croix County in west central Wisconsin...
  Southwestern Chippewa County in west central Wisconsin...
  Western Eau Claire County in west central Wisconsin...

* Until 815 PM CDT.

* At 737 PM CDT, severe thunderstorms were located along a line
  extending from near Woodville to near Weston to Pepin, moving
  northeast at 75 mph.

  HAZARD...70 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect considerable tree damage. Damage is likely to 
           mobile homes, roofs, and outbuildings.

* Severe thunderstorms will be near...
  Menomonie and Knapp around 745 PM CDT.
  Glenwood City and Boyceville around 750 PM CDT.
  Colfax and Wheeler around 755 PM CDT.
  Ridgeland around 800 PM CDT.
  Bloomer and New Auburn around 805 PM CDT.
  Altoona and Lake Hallie around 810 PM CDT.
  Eau Claire and Chippewa Falls around 815 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This is a DANGEROUS SITUATION. These storms are producing widespread 
wind damage. SEEK SHELTER NOW inside a sturdy structure and stay 
away from windows! 

Intense thunderstorm lines can produce brief tornadoes and 
widespread significant wind damage. Although a tornado is not 
immediately likely, it is best to move to an interior room on the 
lowest floor of a building. These storms may cause serious injury 
and significant property damage.

&&

A Tornado Watch remains in effect until midnight CDT for west central
Wisconsin.

LAT...LON 4460 9189 4486 9211 4486 9239 4521 9259
      4521 9138 4459 9138
TIME...MOT...LOC 0037Z 233DEG 66KT 4487 9229 4486 9210 4443 9215 

TORNADO...POSSIBLE
HAIL...<.75IN
WIND...70MPH
 
$$

BORGHOFF
2 follow-up statements
711 
WWUS53 KMPX 210050
SVSMPX

Severe Weather Statement
National Weather Service Twin Cities/Chanhassen MN
750 PM CDT THU SEP 20 2018

WIC017-033-035-091-109-210115-
/O.CON.KMPX.SV.W.0155.000000T0000Z-180921T0115Z/
Pepin WI-Dunn WI-St. Croix WI-Chippewa WI-Eau Claire WI-
750 PM CDT THU SEP 20 2018

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 PM CDT
FOR NORTHEASTERN PEPIN...DUNN...NORTHEASTERN ST. CROIX...SOUTHWESTERN
CHIPPEWA AND WESTERN EAU CLAIRE COUNTIES...

At 750 PM CDT, severe thunderstorms were located along a line
extending from near Reeve to Tainter Lake to near The Big Swamp Area,
moving northeast at 70 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

These severe storms will be near...
  Colfax and Ridgeland around 755 PM CDT.
  Bloomer and New Auburn around 805 PM CDT.
  Altoona around 810 PM CDT.
  Eau Claire around 815 PM CDT.

Other locations impacted by these severe thunderstorms include Cedar
Falls, Caryville, Tainter Lake, Tilden, Wilson, Sand Creek, Downing,
Hersey, Downsville and Emerald.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Intense thunderstorm lines can produce brief tornadoes and 
widespread significant wind damage. Although a tornado is not 
immediately likely, it is best to move to an interior room on the 
lowest floor of a building. These storms may cause serious injury 
and significant property damage.

&&

A Tornado Watch remains in effect until midnight CDT for west central
Wisconsin.

LAT...LON 4460 9189 4486 9211 4486 9215 4521 9238
      4521 9138 4459 9138
TIME...MOT...LOC 0050Z 240DEG 61KT 4520 9208 4497 9183 4455 9184 

TORNADO...POSSIBLE
HAIL...<.75IN
WIND...60MPH
 
$$

BORGHOFF
484 
WWUS53 KMPX 210056
SVSMPX

Severe Weather Statement
National Weather Service Twin Cities/Chanhassen MN
756 PM CDT THU SEP 20 2018

WIC109-210106-
/O.CAN.KMPX.SV.W.0155.000000T0000Z-180921T0115Z/
St. Croix WI-
756 PM CDT THU SEP 20 2018

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN ST. CROIX COUNTY
IS CANCELLED...

The storms which prompted the warning have moved out of the warned 
area. Therefore, the warning has been cancelled.

A Tornado Watch remains in effect until midnight CDT for west central
Wisconsin.

LAT...LON 4460 9189 4489 9203 4521 9213 4521 9138
      4459 9138
TIME...MOT...LOC 0056Z 240DEG 61KT 4525 9198 4501 9173 4459 9174 

$$

WIC017-033-035-091-210115-
/O.CON.KMPX.SV.W.0155.000000T0000Z-180921T0115Z/
Pepin WI-Dunn WI-Chippewa WI-Eau Claire WI-
756 PM CDT THU SEP 20 2018

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 PM CDT
FOR NORTHEASTERN PEPIN...DUNN...SOUTHWESTERN CHIPPEWA AND WESTERN EAU
CLAIRE COUNTIES...

At 756 PM CDT, severe thunderstorms were located along a line
extending from Prairie Farm to Colfax to near Mondovi, moving
northeast at 70 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

These severe storms will be near...
  Colfax around 800 PM CDT.
  Bloomer around 805 PM CDT.
  New Auburn around 810 PM CDT.
  Eau Claire and Altoona around 815 PM CDT.

Other locations impacted by these severe thunderstorms include Cedar
Falls, Caryville, Tainter Lake, Tilden, Sand Creek, Downsville,
Menomonie Airport, Rock Falls, Hoffman Hills Rec Area and Eau Claire
Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A tornado watch remains in effect for the warned area. Tornadoes can
develop quickly from severe thunderstorms. Although a tornado is not
immediately likely, if one is spotted act quickly and move to a place
of safety inside a sturdy structure, such as a basement or small
interior room.

&&

LAT...LON 4460 9189 4489 9203 4521 9213 4521 9138
      4459 9138
TIME...MOT...LOC 0056Z 240DEG 61KT 4525 9198 4501 9173 4459 9174 

HAIL...<.75IN
WIND...60MPH
 
$$

BORGHOFF

The office that day

Everything else NWS Twin Cities, MN issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 20, 7:05 PM CDTSpecial Weather StatementMPXBarron, Polk3 hr
Sep 20, 7:13 PM CDTTornado WarningMPXDunn, Pepin, Pierce36 min
Sep 20, 8:08 PM CDTSevere Thunderstorm WarningMPXChippewa, Eau Claire37 min

Nearby

Severe Thunderstorm Warnings in Wisconsin, 2018Every severe thunderstorm warning in 2018

Sources

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