Alert archive / Wisconsin / Tornado Warnings in 2007

Tornado Warning 40, NWS Twin Cities, MN

September 20, 2007Pierce County, Saint Croix County, Wisconsin

NWS Twin Cities, MN issued this tornado warning at Sep 20, 2007, 6:56 PM CDT for Pierce County, Saint Croix County, Wisconsin. It was in force for 34 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, 2007, 6:56 PM CDT (23:56 UTC)
Expired
Sep 20, 2007, 7:30 PM CDT
In force
34 min
Issued by
NWS Twin Cities, MN
Area
Counties, with a storm outline in the text

Counties Pierce County, WI, Saint Croix County, WI

The radar

The Minneapolis radar (KMPX), 92 km from the middle of the area, began a volume at 23:57 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, 7:17 PM CDTFUNNEL CLOUD3 Nw Ellsworth, WI

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, 5:37 PM CDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 11.9 hours before the alert went out and 95 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 2007-09-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Minneapolis, MN at 12:00Z on 2007-09-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 215 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1024 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
215 m²/s²
0-3 km storm-relative helicity
291 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.

000 
WFUS53 KMPX 202356
TORMPX
WIC093-109-210030-
/O.NEW.KMPX.TO.W.0040.070920T2356Z-070921T0030Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
656 PM CDT THU SEP 20 2007

THE NATIONAL WEATHER SERVICE IN THE TWIN CITIES HAS ISSUED A

* TORNADO WARNING FOR...
  ST. CROIX COUNTY IN WEST CENTRAL WISCONSIN...
  PIERCE COUNTY IN WEST CENTRAL WISCONSIN...

* UNTIL 730 PM CDT

* AT 652 PM CDT...TRAINED WEATHER SPOTTERS REPORTED A FUNNEL CLOUD
  NEAR RIVER FALLS...OR ABOUT 11 MILES SOUTHEAST OF HUDSON. RADAR
  SHOWED THE SEVERE STORM ..AND MOVING EAST AT 40 MPH.

  RADAR ALSO INDICATED ROTATION IN THE STORM.

* LOCATIONS IMPACTED INCLUDE...
  BELDENVILLE...
  MARTEL...
  WOODVILLE...
  SPRING VALLEY...
  
THE SAFEST PLACE TO BE DURING A TORNADO IS IN A BASEMENT. GET UNDER A
WORKBENCH OR OTHER PIECE OF STURDY FURNITURE. IF NO BASEMENT IS
AVAILABLE...SEEK SHELTER ON THE LOWEST FLOOR OF THE BUILDING IN AN
INTERIOR HALLWAY OR ROOM SUCH AS A CLOSET. USE BLANKETS OR PILLOWS TO
COVER YOUR BODY AND ALWAYS STAY AWAY FROM WINDOWS.

IF IN MOBILE HOMES OR VEHICLES...EVACUATE THEM AND GET INSIDE A
SUBSTANTIAL SHELTER. IF NO SHELTER IS AVAILABLE...LIE FLAT IN THE
NEAREST DITCH OR OTHER LOW SPOT AND COVER YOUR HEAD WITH YOUR HANDS.

LAT...LON 4496 9217 4475 9219 4476 9273 4492 9274
TIME...MOT...LOC 2356Z 264DEG 37KT 4485 9253

$$

DWE
1 follow-up statement
000 
WWUS53 KMPX 210028
SVSMPX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
724 PM CDT THU SEP 20 2007

WIC093-109-210034-
/O.EXP.KMPX.TO.W.0040.000000T0000Z-070921T0030Z/
ST. CROIX WI-PIERCE WI-
724 PM CDT THU SEP 20 2007

...THE TORNADO WARNING FOR PIERCE AND ST. CROIX COUNTIES EXPIRES AT
730 PM CDT...

AT 715 PM CDT...A FUNNEL CLOUD WAS REPORTED 3 TO 4 MILES NORTHWEST 
OF ELLSWORTH. THE SEVERE STORM HAS WEAKENED...BUT COULD STILL 
PRODUCE HAIL. 

A TORNADO WATCH REMAINS IN EFFECT UNTIL 1000 PM CDT THURSDAY EVENING
FOR SOUTHERN MINNESOTA.

LAT...LON 4496 9217 4475 9219 4476 9273 4492 9274
TIME...MOT...LOC 0024Z 264DEG 37KT 4488 9213

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 20, 1:04 PM CDTFlash Flood WatchMPXPierce, Polk, Saint Croix18 hr
Sep 20, 6:07 PM CDTSevere Thunderstorm WarningMPXPierce, Saint Croix53 min

Nearby

Tornado Warnings in Wisconsin, 2007Every tornado warning in 2007Tornadoes in 2007

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.