Alert archive / Wisconsin / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 79, NWS Twin Cities, MN

August 8, 2009Polk County, Saint Croix County, Wisconsin

NWS Twin Cities, MN issued this severe thunderstorm warning at Aug 8, 2009, 8:37 AM CDT for Polk County, Saint Croix County, 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
Aug 8, 2009, 8:37 AM CDT (13:37 UTC)
Expired
Aug 8, 2009, 9:15 AM CDT
In force
38 min
Issued by
NWS Twin Cities, MN
Area
Storm-based polygon

Counties Polk County, WI, Saint Croix County, WI

The radar

The Minneapolis radar (KMPX), 108 km from the middle of the area, began a volume at 13:37 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, 8:40 AM CDTHAIL 0.755 N New Richmond, WI

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, 1.6 hours before the alert went out and 110 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 2009-08-08Temperature 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 2009-08-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 237 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
-296 J/kg
Mixed-layer LCL
896 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
237 m²/s²
0-3 km storm-relative helicity
260 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.2

Open this sounding in Storm Lab

The text

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

000 
WUUS53 KMPX 081337
SVRMPX
WIC095-109-081415-
/O.NEW.KMPX.SV.W.0079.090808T1337Z-090808T1415Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
837 AM CDT SAT AUG 8 2009

THE NATIONAL WEATHER SERVICE IN THE TWIN CITIES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHEASTERN POLK COUNTY IN NORTHWEST WISCONSIN...
  NORTHEASTERN ST. CROIX COUNTY IN WEST CENTRAL WISCONSIN...

* UNTIL 915 AM CDT

* AT 837 AM CDT...RADAR INDICATED A SEVERE THUNDERSTORM...CAPABLE OF
  PRODUCING LARGE DAMAGING HAIL UP TO GOLF BALL SIZE AND DAMAGING
  WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED NEAR STAR
  PRAIRIE...OR ABOUT 6 MILES NORTH OF NEW RICHMOND...AND MOVING EAST
  AT 20 MPH.

LOCATIONS IN THE WARNING INCLUDE...
  AMERY...
  WANDEROOS...
  DERONDA...
  DEER PARK...
  CLEAR LAKE...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS SITUATION. IF YOU ARE IN THE PATH OF THIS
STORM...PREPARE IMMEDIATELY FOR DESTRUCTIVE HAIL...WHICH CAN
SIGNIFICANTLY DAMAGE WINDOWS...SIDING AND VEHICLES. DAMAGING WINDS
ARE ALSO EXPECTED...WHICH WILL UPROOT TREES AND DOWN POWER LINES.
SEEK SHELTER NOW INSIDE A STURDY STRUCTURE AND STAY AWAY FROM
WINDOWS.

&&

LAT...LON 4538 9216 4513 9216 4515 9255 4529 9261
TIME...MOT...LOC 1337Z 268DEG 19KT 4521 9251

$$

MDB
1 follow-up statement
000 
WWUS53 KMPX 081401
SVSMPX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
901 AM CDT SAT AUG 8 2009

WIC095-109-081415-
/O.CON.KMPX.SV.W.0079.000000T0000Z-090808T1415Z/
POLK WI-ST. CROIX WI-
901 AM CDT SAT AUG 8 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 915 AM CDT
FOR NORTHEASTERN ST. CROIX AND SOUTHEASTERN POLK COUNTIES...

AT 849 AM CDT...TREES WERE REPORTED DOWN IN STAR PRAIRIE.

AT 901 AM CDT...RADAR CONTINUED TO INDICATE A SEVERE THUNDERSTORM...
CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS OF 60 MPH. THE SEVERE
STORM WAS LOCATED 3 MILES SOUTHEAST OF CLEAR LAKE...AND MOVING EAST
AT 30 MPH.

LOCATIONS IN THE WARNING INCLUDE...
  MAINLY RURAL AREAS OF EXTREME SOUTHEASTERN POLK AND NORTHEASTERN
  ST. CROIX COUNTIES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU ARE IN THE PATH OF THIS STORM...PREPARE IMMEDIATELY FOR
DAMAGING WINDS. SEEK SHELTER NOW INSIDE A STURDY STRUCTURE AND STAY
AWAY FROM WINDOWS.

&&

LAT...LON 4529 9216 4513 9216 4516 9236 4528 9236
TIME...MOT...LOC 1401Z 269DEG 26KT 4521 9223

$$

MDB

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 8, 12:24 AM CDTAreal Flood AdvisoryMPXPierce, Saint Croix3 hr
Aug 8, 12:28 AM CDTAreal Flood AdvisoryMPXPierce, Saint Croix3 hr
Aug 8, 2:03 AM CDTFlash Flood WarningMPXDunn, Eau Claire, Pepin, Pierce4 hr
Aug 8, 4:06 AM CDTFlash Flood WatchMPXChippewa, Dunn, Eau Claire, Pepin, Pierce, Saint Croix19 hr
Aug 8, 8:11 AM CDTSpecial Weather StatementMPXPolk49 min
Aug 8, 9:05 AM CDTSpecial Weather StatementMPXBarron40 min
Aug 8, 10:18 AM CDTSpecial Weather StatementMPXChippewa42 min
Aug 8, 10:33 AM CDTSpecial Weather StatementMPXSaint Croix57 min
Aug 8, 10:59 AM CDTSevere Thunderstorm WarningMPXDunn, Saint Croix46 min
Aug 8, 11:58 AM CDTSpecial Weather StatementMPXChippewa47 min

Nearby

Severe Thunderstorm Warnings in Wisconsin, 2009Every severe thunderstorm warning 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.