Alert archive / Wisconsin / Tornado Warnings in 2009

Tornado Warning 41, NWS Twin Cities, MN

August 19, 2009Pierce County, Saint Croix County, Wisconsin

NWS Twin Cities, MN issued this tornado warning at Aug 19, 2009, 2:57 PM CDT for Pierce County, Saint Croix County, Wisconsin. It was in force for 48 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
Aug 19, 2009, 2:57 PM CDT (19:57 UTC)
Expired
Aug 19, 2009, 3:45 PM CDT
In force
48 min
Issued by
NWS Twin Cities, MN
Area
Storm-based polygon

Counties Pierce County, WI, Saint Croix County, WI

The radar

The Minneapolis radar (KMPX), 88 km from the middle of the area, began a volume at 19:58 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
Aug 19, 2:57 PM CDTTORNADO5 Se Ellsworth, WIDAMAGE SURVEY DETERMINED AN EF-0 TORNADO TOUCHED DOWN BRIEFLY JUST NORTH OF THE INTERSECTION OF COUNTY ROADS DD AND V. THE TORNADO KNOCKED DOWN A NARROW STRIP OF CORN FOR 0.2 MILE.

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

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 8.0 hours before the alert went out and 91 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 2009-08-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 368 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, Minneapolis, MN at 12:00Z on 2009-08-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 121 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
368 J/kg
Mixed-layer CIN
-49 J/kg
Mixed-layer LCL
615 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
121 m²/s²
0-3 km storm-relative helicity
68 m²/s²
Significant tornado parameter
0.2
Supercell composite
3.0

Open this sounding in Storm Lab

The text

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

000 
WFUS53 KMPX 191957
TORMPX
WIC093-109-192045-
/O.NEW.KMPX.TO.W.0041.090819T1957Z-090819T2045Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
257 PM CDT WED AUG 19 2009

THE NATIONAL WEATHER SERVICE IN THE TWIN CITIES HAS ISSUED A

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

* UNTIL 345 PM CDT

* AT 257 PM CDT...RADAR INDICATED A STORM CAPABLE OF PRODUCING A
  TORNADO. THE MOST DANGEROUS PART OF THE STORM WAS 3 MILES SOUTHEAST
  OF ELLSWORTH...OR ABOUT 6 MILES SOUTHEAST OF BELDENVILLE...AND
  MOVING NORTH AT 30 MPH.

* LOCATIONS IN THE WARNING INCLUDE...
  ELLSWORTH...
  BELDENVILLE...
  MARTEL...
  SPRING VALLEY...
  ROBERTS...
  HAMMOND...
  BALDWIN...
  WOODVILLE...
  HERSEY...
  WILSON...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

WHEN A TORNADO WARNING IS ISSUED BASED ON RADAR...IT MEANS THAT
STRONG ROTATION HAS BEEN DETECTED IN THE STORM. A TORNADO MAY ALREADY
BE ON THE GROUND...OR IS EXPECTED TO DEVELOP SHORTLY.

IF YOU ARE CAUGHT OUTSIDE...SEEK SHELTER IN A NEARBY REINFORCED
BUILDING. AS A LAST RESORT...SEEK SHELTER IN A CULVERT...DITCH OR LOW
SPOT AND COVER YOUR HEAD WITH YOUR HANDS.

&&

LAT...LON 4486 9252 4487 9267 4506 9256 4501 9214
      4486 9214 4458 9237 4464 9263
TIME...MOT...LOC 1957Z 202DEG 28KT 4471 9244

$$
1 follow-up statement
000 
WWUS53 KMPX 192020
SVSMPX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
320 PM CDT WED AUG 19 2009

WIC093-109-192045-
/O.CON.KMPX.TO.W.0041.000000T0000Z-090819T2045Z/
ST. CROIX WI-PIERCE WI-
320 PM CDT WED AUG 19 2009

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 345 PM CDT FOR PIERCE
AND SOUTHERN ST. CROIX COUNTIES...

AT 319 PM CDT...RADAR CONTINUED TO INDICATE A SEVERE THUNDERSTORM
CAPABLE OF PRODUCING A TORNADO.  THE MOST DANGEROUS PART OF THE STORM
WAS LOCATED NEAR MARTEL...AND MOVING NORTH AT 30 MPH.  ADDITIONAL 
STRONG THUNDERSTORMS WERE LOCATED IN THE AREA...AND THEY COULD 
PRODUCE A BRIEF TORNADO.  

LOCATIONS IN THE WARNING INCLUDE...
SPRING VALLEY...ROBERTS...HAMMOND...BALDWIN...WOODVILLE...HERSEY AND
WILSON.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

WHEN A TORNADO WARNING IS ISSUED BASED ON RADAR...IT MEANS THAT
STRONG ROTATION HAS BEEN DETECTED IN THE STORM. A TORNADO MAY ALREADY
BE ON THE GROUND...OR IS EXPECTED TO DEVELOP SHORTLY.

IF YOU ARE CAUGHT OUTSIDE...SEEK SHELTER IN A NEARBY REINFORCED
BUILDING. AS A LAST RESORT...SEEK SHELTER IN A CULVERT...DITCH OR LOW
SPOT AND COVER YOUR HEAD WITH YOUR HANDS.

&&

LAT...LON 4458 9237 4464 9263 4486 9252 4492 9249
      4497 9261 4506 9256 4501 9214 4486 9214
TIME...MOT...LOC 2019Z 198DEG 25KT 4484 9237

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 19, 2:43 PM CDTTornado WarningMPXPierce32 min
Aug 19, 2:53 PM CDTTornado WarningMPXSaint Croix22 min
Aug 19, 3:16 PM CDTTornado WarningMPXPolk, Saint Croix29 min
Aug 19, 4:04 PM CDTTornado WarningMPXDunn, Saint Croix26 min
Aug 19, 4:06 PM CDTTornado WarningMPXPierce, Saint Croix39 min
Aug 19, 4:14 PM CDTTornado WarningMPXBarron, Polk46 min
Aug 19, 4:21 PM CDTTornado WarningMPXPolk39 min
Aug 19, 4:33 PM CDTTornado WarningMPXSaint Croix27 min
Aug 19, 4:43 PM CDTTornado WarningMPXDunn, Pierce, Saint Croix47 min
Aug 19, 5:13 PM CDTTornado WarningMPXBarron, Dunn, Polk, Saint Croix47 min

Nearby

Tornado Warnings in Wisconsin, 2009Every tornado warning in 2009Tornadoes in 2009

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.