Alert archive / Wisconsin / Tornado Warnings in 2009

Tornado Warning 33, NWS Twin Cities, MN

August 8, 2009Polk County, Saint Croix County, Wisconsin; Washington County, Minnesota

NWS Twin Cities, MN issued this tornado warning at Aug 8, 2009, 10:14 PM CDT for Polk County, Saint Croix County, Wisconsin; Washington County, Minnesota. It was in force for 31 min. 3 reports 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 8, 2009, 10:14 PM CDT (03:14 UTC)
Expired
Aug 8, 2009, 10:45 PM CDT
In force
31 min
Issued by
NWS Twin Cities, MN
Area
Storm-based polygon

Counties Washington County, MN, Polk County, WI, Saint Croix County, WI

The radar

The Minneapolis radar (KMPX), 85 km from the middle of the area, began a volume at 03:16 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 8, 10:20 PM CDTTSTM WND DMG2 Ssw East Farmington, WITREE DOWN ACROSS ROAD.
Aug 8, 10:25 PM CDTTSTM WND DMG4 E East Farmington, WIABOUT SIX TREES DOWNED FROM A DOWNBURST.
Aug 8, 10:37 PM CDTHAIL 0.5New Richmond, WIREPORTED BY AIRPORT MANAGER.

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
Aug 8, 3:46 PM CDTTornado WatchSPC8 hr

The nearest sounding before it

Minneapolis, MN (KMPX), launched 00:00Z, 3.2 hours before the alert went out and 88 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 00:00Z on 2009-08-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3715 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 00:00Z on 2009-08-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 190 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
3715 J/kg
Mixed-layer CIN
-17 J/kg
Mixed-layer LCL
841 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
190 m²/s²
0-3 km storm-relative helicity
163 m²/s²
Significant tornado parameter
3.8
Supercell composite
16.8

Open this sounding in Storm Lab

The text

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

000 
WFUS53 KMPX 090314
TORMPX
MNC163-WIC095-109-090345-
/O.NEW.KMPX.TO.W.0033.090809T0314Z-090809T0345Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1014 PM CDT SAT AUG 8 2009

THE NATIONAL WEATHER SERVICE IN THE TWIN CITIES HAS ISSUED A

* TORNADO WARNING FOR...
  NORTHEAST WASHINGTON COUNTY IN EAST CENTRAL MINNESOTA...
  SOUTHWESTERN POLK COUNTY IN NORTHWEST WISCONSIN...
  NORTHWESTERN ST. CROIX COUNTY IN WEST CENTRAL WISCONSIN...

* UNTIL 1045 PM CDT

* AT 1013 PM CDT...RADAR WAS TRACKING A SEVERE STORM WITH STRONG
  ROTATION. THE MOST DANGEROUS PART OF THE STORM WAS NEAR MARINE
  ON ST CROIX...AND MOVING EAST AT 25 MPH.

* LOCATIONS IN THE WARNING INCLUDE...
  NEW RICHMOND...
  SOMERSET...
  STAR PRAIRIE...
  HUNTINGTON...
  MARINE ON ST CROIX...
  AREAS EAST OF EAST FARMINGTON...

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.

&&

LAT...LON 4528 9247 4511 9241 4510 9279 4521 9284
TIME...MOT...LOC 0313Z 253DEG 22KT 4517 9277

$$
1 follow-up statement
000 
WWUS53 KMPX 090326
SVSMPX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1026 PM CDT SAT AUG 8 2009

MNC163-090334-
/O.CAN.KMPX.TO.W.0033.000000T0000Z-090809T0345Z/
WASHINGTON MN-
1026 PM CDT SAT AUG 8 2009

...THE TORNADO WARNING FOR NORTHEAST WASHINGTON COUNTY IS 
CANCELLED...

RADAR INDICATED THAT THE SEVERE STORM HAD WEAKENED OR MOVED OUT OF
THE WARNED AREA. THEREFORE...THE TORNADO WARNING HAS BEEN CANCELLED.

THERE ARE NO MORE TORNADO WARNINGS FOR ANY PART OF WASHINGTON COUNTY 
AT THIS TIME. 

A TORNADO WATCH REMAINS IN EFFECT UNTIL MIDNIGHT CDT SUNDAY MORNING
FOR EAST CENTRAL MINNESOTA AND NORTHWESTERN WISCONSIN.

LAT...LON 4510 9270 4523 9274 4528 9247 4511 9241
TIME...MOT...LOC 0324Z 253DEG 22KT 4519 9267

$$

WIC095-109-090345-
/O.CON.KMPX.TO.W.0033.000000T0000Z-090809T0345Z/
POLK WI-ST. CROIX WI-
1026 PM CDT SAT AUG 8 2009

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1045 PM CDT FOR
NORTHWESTERN ST. CROIX AND SOUTHWESTERN POLK COUNTIES...

AT 1023 PM CDT...RADAR INDICATED A SEVERE THUNDERSTORM WITH STRONG
ROTATION.  THE MOST DANGEROUS PART OF THE STORM WAS LOCATED 4 MILES
NORTH OF SOMERSET...AND MOVING EAST AT 25 MPH.

LOCATIONS IN THE WARNING INCLUDE...
NEW RICHMOND...STAR PRAIRIE...HUNTINGTON AND AREAS EAST OF EAST 
FARMINGTON.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS STORM HAS A HISTORY OR PRODUCING TORNADOES AND LARGE DAMAGING
HAIL.

&&

LAT...LON 4510 9270 4523 9274 4528 9247 4511 9241
TIME...MOT...LOC 0324Z 253DEG 22KT 4519 9267

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 8, 9:43 PM CDTTornado WarningMPXPolk, Saint Croix32 min
Aug 8, 10:01 PM CDTTornado WarningMPXSaint Croix29 min
Aug 8, 10:29 PM CDTTornado WarningMPXSaint Croix46 min
Aug 8, 11:14 PM CDTTornado WarningMPXDunn, Saint Croix46 min
Aug 9, 12:00 AM CDTTornado WarningMPXDunn30 min
Aug 9, 12:36 AM CDTSpecial Weather StatementMPXChippewa, Eau Claire54 min
Aug 9, 1:27 AM CDTSpecial Weather StatementMPXChippewa33 min
Aug 8, 8:31 PM CDTTornado WarningMPXHennepin29 min
Aug 8, 8:49 PM CDTTornado WarningMPXAnoka, Hennepin, Ramsey26 min
Aug 8, 9:13 PM CDTTornado WarningMPXAnoka, Ramsey, Washington32 min

Nearby

Tornado Warnings in Wisconsin, 2009Tornado Warnings in Minnesota, 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.