Alert archive / Minnesota / Tornado Warnings in 2009

Tornado Warning 42, NWS Twin Cities, MN

August 19, 2009Polk County, Saint Croix County, Wisconsin; Anoka County, Ramsey County, Washington County, Minnesota

NWS Twin Cities, MN issued this tornado warning at Aug 19, 2009, 3:16 PM CDT for Polk County, Saint Croix County, Wisconsin; Anoka County, Ramsey County, Washington County, Minnesota. It was in force for 29 min. 2 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 19, 2009, 3:16 PM CDT (20:16 UTC)
Expired
Aug 19, 2009, 3:45 PM CDT
In force
29 min
Issued by
NWS Twin Cities, MN
Area
Storm-based polygon

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

The radar

The Minneapolis radar (KMPX), 72 km from the middle of the area, began a volume at 20:16 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 19, 3:25 PM CDTTORNADOS Marine On St Croix, MNDAMAGE SURVEY REVEALED AN EF-0 TORNADO MOVED 0.7 MILE THROUGH THE WESTERN SECTION OF MARINE ON ST CROIX. SCATTERED TREES AND LARGE LIMBS WERE DOWNED.
Aug 19, 3:30 PM CDTTSTM WND DMG1 E Hudson, WI4 INCH BRANCHES IN ROAD AND WHOLE TREES DOWN ON HWY 12 ONE HALF TO ONE MILE EAST OF HUDSON.

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, 8.3 hours before the alert went out and 74 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 192016
TORMPX
MNC003-123-163-WIC095-109-192045-
/O.NEW.KMPX.TO.W.0042.090819T2016Z-090819T2045Z/

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

THE NATIONAL WEATHER SERVICE IN THE TWIN CITIES HAS ISSUED A

* TORNADO WARNING FOR...
  EASTERN ANOKA COUNTY IN EAST CENTRAL MINNESOTA...
  NORTHERN WASHINGTON COUNTY IN EAST CENTRAL MINNESOTA...
  NORTHERN RAMSEY COUNTY IN EAST CENTRAL MINNESOTA...
  SOUTHWESTERN POLK COUNTY IN NORTHWEST WISCONSIN...
  NORTHWESTERN ST. CROIX COUNTY IN WEST CENTRAL WISCONSIN...

* UNTIL 345 PM CDT

* AT 315 PM CDT...RADAR INDICATED A LINE OF STORMS CAPABLE OF        
  PRODUCING BRIEF TORNADOS. THE MOST DANGEROUS PART OF THE           
  STORM WAS SHOREVIEW TO BURKHARDT...AND MOVING NORTH AT 35 MPH.

* LOCATIONS IN THE WARNING INCLUDE...
  WILLERNIE...
  VADNAIS HEIGHTS...
  MAHTOMEDI...
  STILLWATER...
  NEW BRIGHTON...
  WHITE BEAR LAKE...
  ARDEN HILLS...
  SHOREVIEW...
  MOUNDS VIEW...
  NORTH OAKS...
  SOMERSET...
  CIRCLE PINES...

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 4530 9301 4530 9274 4533 9269 4535 9269
      4538 9267 4537 9240 4497 9261 4495 9299
      4504 9321 4539 9321 4538 9302
TIME...MOT...LOC 2015Z 181DEG 32KT 4502 9270

$$
1 follow-up statement
000 
WWUS53 KMPX 192029
SVSMPX

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

MNC003-123-163-WIC095-109-192045-
/O.CON.KMPX.TO.W.0042.000000T0000Z-090819T2045Z/
ANOKA MN-WASHINGTON MN-RAMSEY MN-POLK WI-ST. CROIX WI-
329 PM CDT WED AUG 19 2009

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 345 PM CDT FOR
NORTHWESTERN ST. CROIX...SOUTHWESTERN POLK...NORTHERN RAMSEY...
NORTHERN WASHINGTON AND EASTERN ANOKA COUNTIES...

AT 327 PM CDT...RADAR CONTINUED TO INDICATE A NUMBER OF 
THUNDERSTORMS LOCATED FROM NEAR BLAINE EAST THROUGH HUGO TO STAR 
PRAIRIE. THESE STORMS COULD PRODUCE BRIEF TORNADOES AS THEY MOVE 
NORTH AT 40 MPH.

LOCATIONS IN THE WARNING INCLUDE...
MARINE ON ST CROIX...STAR PRAIRIE...OTISVILLE...HAM LAKE...SCANDIA...
FOREST LAKE...WANDEROOS...OSCEOLA...DRESSER...EAST BETHEL...
HUNTINGTON AND 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.

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 4538 9304 4534 9301 4530 9302 4530 9274
      4533 9269 4538 9266 4537 9240 4501 9259
      4505 9296 4510 9321 4539 9321
TIME...MOT...LOC 2027Z 182DEG 33KT 4516 9275

$$

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, 2:57 PM CDTTornado WarningMPXPierce, Saint Croix48 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
Aug 18, 11:39 PM CDTSevere Thunderstorm WarningMPXChippewa, Lac qui Parle, Stevens, Swift36 min
Aug 19, 12:20 AM CDTSpecial Weather StatementMPXSwift40 min
Aug 19, 12:41 AM CDTSevere Thunderstorm WarningMPXChippewa, Kandiyohi, Swift34 min
Aug 19, 12:59 AM CDTSpecial Weather StatementMPXSwift46 min
Aug 19, 1:18 AM CDTSpecial Weather StatementMPXKandiyohi42 min
Aug 19, 2:16 AM CDTAreal Flood AdvisoryMPXChippewa, Kandiyohi, Lac qui Parle, Meeker, Swift5 hr
Aug 19, 1:04 PM CDTAreal Flood AdvisoryMPXAnoka, Carver, Chisago, Hennepin, Isanti, Kanabec and 7 more6 hr
Aug 19, 2:11 PM CDTTornado WarningMPXAnoka, Hennepin, Ramsey34 min
Aug 19, 2:16 PM CDTTornado WarningMPXDakota29 min
Aug 19, 3:46 PM CDTTornado WarningMPXAnoka, Chisago, Washington29 min
Aug 19, 4:49 PM CDTSevere Thunderstorm WarningMPXRedwood, Yellow Medicine41 min
Aug 19, 5:18 PM CDTSevere Thunderstorm WarningMPXRedwood21 min
Aug 19, 5:24 PM CDTSpecial Weather StatementMPXChippewa, Swift51 min
Aug 19, 6:02 PM CDTSevere Thunderstorm WarningMPXBrown, Redwood58 min
Aug 19, 6:19 PM CDTTornado WarningMPXBrown26 min
Aug 19, 6:29 PM CDTTornado WarningMPXBrown31 min
Aug 19, 6:39 PM CDTTornado WarningMPXBrown36 min
Aug 19, 6:44 PM CDTSevere Thunderstorm WarningMPXChippewa, Renville44 min

Nearby

Tornado Warnings in Minnesota, 2009Tornado 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.