Alert archive / Minnesota / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 21, NWS Twin Cities, MN

May 1, 2012Polk County, Wisconsin; Anoka County, Chisago County, Isanti County, Minnesota

NWS Twin Cities, MN issued this severe thunderstorm warning at May 1, 2012, 8:08 PM CDT for Polk County, Wisconsin; Anoka County, Chisago County, Isanti County, Minnesota. It was in force for 37 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
May 1, 2012, 8:08 PM CDT (01:08 UTC)
Expired
May 1, 2012, 8:45 PM CDT
In force
37 min
Issued by
NWS Twin Cities, MN
Area
Storm-based polygon
Hail
0.88 in
Wind
60.0 mph

Counties Anoka County, MN, Chisago County, MN, Isanti County, MN, Polk County, WI

The radar

The Minneapolis radar (KMPX), 99 km from the middle of the area, began a volume at 01:08 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.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
May 1, 6:10 PM CDTTornado WatchSPC6 hr

The nearest sounding before it

Minneapolis, MN (KMPX), launched 00:00Z, 1.1 hours before the alert went out and 101 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 2012-05-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 279 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 2012-05-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 227 square meters per square second.1939587897Sfc1 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
279 J/kg
Mixed-layer CIN
-111 J/kg
Mixed-layer LCL
1279 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
227 m²/s²
0-3 km storm-relative helicity
393 m²/s²
Significant tornado parameter
0.2
Supercell composite
4.9

Open this sounding in Storm Lab

The text

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

696 
WUUS53 KMPX 020108
SVRMPX
MNC003-025-059-WIC095-020145-
/O.NEW.KMPX.SV.W.0021.120502T0108Z-120502T0145Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
808 PM CDT TUE MAY 1 2012

THE NATIONAL WEATHER SERVICE IN THE TWIN CITIES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHEAST ANOKA COUNTY IN EAST CENTRAL MINNESOTA...
  CHISAGO COUNTY IN EAST CENTRAL MINNESOTA...
  EASTERN ISANTI COUNTY IN EAST CENTRAL MINNESOTA...
  NORTHWESTERN POLK COUNTY IN NORTHWEST WISCONSIN...

* UNTIL 845 PM CDT

* AT 803 PM CDT...RADAR INDICATED A LINE OF SEVERE THUNDERSTORMS...
  CAPABLE OF PRODUCING DAMAGING WINDS OF 60 MPH. THESE STORMS WERE
  LOCATED ALONG A LINE EXTENDING FROM 5 MILES EAST OF STANCHFIELD TO
  BODUM TO ST FRANCIS...AND MOVING EAST AT 35 MPH.  NICKEL SIZE HAIL
  MAY ALSO ACCOMPANY THESE DAMAGING WINDS.

LOCATIONS IN THE WARNING INCLUDE...
  NORTH BRANCH...
  BODUM...
  ISANTI...
  ST FRANCIS...
  RUSH CITY...
  EAST BETHEL...
  HARRIS...
  BRANCH...
  WYOMING...
  STACY...
  WOLF CREEK...
  CHISAGO CITY...
  LINDSTROM...
  CUSHING...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU ARE IN THE PATH OF THIS STORM...PREPARE IMMEDIATELY FOR
DAMAGING WINDS IN EXCESS OF 60 MPH AND HAIL. SEEK SHELTER NOW INSIDE
A STURDY STRUCTURE AND STAY AWAY FROM WINDOWS.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 1000 PM CDT TUESDAY EVENING
FOR SOUTHERN MINNESOTA. A TORNADO WATCH ALSO REMAINS IN EFFECT UNTIL
100 AM CDT WEDNESDAY MORNING FOR SOUTHEASTERN MINNESOTA AND
NORTHWESTERN WISCONSIN.

&&

LAT...LON 4549 9261 4532 9287 4535 9350 4552 9324
      4574 9312 4573 9286 4565 9287 4565 9254
      4573 9254 4573 9248
TIME...MOT...LOC 0108Z 273DEG 29KT 4567 9302 4551 9311
          4540 9327
WIND...HAIL 60MPH 0.88IN

$$

The office that day

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

IssuedProductOfficeCountiesLasted
May 1, 7:08 PM CDTSevere Thunderstorm WarningMPXSherburne, Stearns, Wright52 min
May 1, 7:23 PM CDTSpecial Weather StatementMPXIsanti, Kanabec52 min
May 1, 7:24 PM CDTSevere Thunderstorm WarningMPXCarver, McLeod, Sibley51 min
May 1, 7:30 PM CDTSevere Thunderstorm WarningMPXChisago, Isanti, Kanabec45 min
May 1, 7:55 PM CDTSpecial Weather StatementMPXAnoka50 min
May 1, 8:09 PM CDTSevere Thunderstorm WarningMPXBrown, Nicollet, Sibley66 min
May 1, 8:13 PM CDTSevere Thunderstorm WarningMPXBrown, Redwood25 min
May 1, 9:24 PM CDTSpecial Weather StatementMPXNicollet, Sibley51 min
May 1, 10:11 PM CDTSpecial Weather StatementMPXBlue Earth, Faribault, Le Sueur, Martin, Nicollet49 min
May 1, 11:12 PM CDTSpecial Weather StatementMPXFreeborn, Rice, Steele, Waseca48 min
May 2, 5:22 PM CDTSevere Thunderstorm WarningMPXBlue Earth, Brown, Watonwan53 min
May 2, 5:50 PM CDTTornado WarningMPXBlue Earth, Brown, Nicollet, Watonwan40 min
May 2, 6:20 PM CDTSevere Thunderstorm WarningMPXBlue Earth, Le Sueur, Nicollet, Waseca55 min
May 2, 6:45 PM CDTSevere Thunderstorm WarningMPXGoodhue, Rice, Steele60 min
May 2, 6:45 PM CDTSevere Thunderstorm WarningMPXBrown, Redwood60 min
May 2, 6:58 PM CDTSevere Thunderstorm WarningMPXLe Sueur, Rice, Steele, Waseca47 min

Nearby

Severe Thunderstorm Warnings in Minnesota, 2012Severe Thunderstorm Warnings in Wisconsin, 2012Every severe thunderstorm warning in 2012

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.