Alert archive / Minnesota / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 20, NWS Twin Cities, MN

May 1, 2012Chisago County, Isanti County, Kanabec County, Minnesota

NWS Twin Cities, MN issued this severe thunderstorm warning at May 1, 2012, 7:30 PM CDT for Chisago County, Isanti County, Kanabec County, Minnesota. It was in force for 45 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: May 1, 2012, 7:30 PM CDT (00:30 UTC)
Expired: May 1, 2012, 8:15 PM CDT
In force: 45 min
Issued by: NWS Twin Cities, MN
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Chisago County, MN, Isanti County, MN, Kanabec County, MN

The radar

The Minneapolis radar (KMPX), 100 km from the middle of the area, began a volume at 00:31 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

Time	Report	Where	Remark
May 1, 7:42 PM CDT	TSTM WND GST 75	Spencer Brook, MN	DELAYED REPORT FROM MAY 1ST. 3 LARGE TREES BLOW OVER AND ROOF DAMAGE NOTED.

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.

Issued	Product	Office	Lasted
May 1, 6:10 PM CDT	Tornado Watch	SPC	6 hr

The nearest sounding before it

Minneapolis, MN (KMPX), launched 00:00Z, 0.5 hours before the alert went out and 100 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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.

180 
WUUS53 KMPX 020030
SVRMPX
MNC025-059-065-020115-
/O.NEW.KMPX.SV.W.0020.120502T0030Z-120502T0115Z/

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

THE NATIONAL WEATHER SERVICE IN THE TWIN CITIES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHWESTERN CHISAGO COUNTY IN EAST CENTRAL MINNESOTA...
  ISANTI COUNTY IN EAST CENTRAL MINNESOTA...
  SOUTHERN KANABEC COUNTY IN EAST CENTRAL MINNESOTA...

* UNTIL 815 PM CDT

* AT 727 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 OGILVIE TO DALBO TO
  ZIMMERMAN...AND MOVING EAST AT 20 MPH.  PENNY SIZE HAIL MAY ALSO
  ACCOMPANY THESE DAMAGING WINDS.

LOCATIONS IN THE WARNING INCLUDE...
  MORA...
  CAMBRIDGE...
  DALBO...
  OGILVIE...
  LEWIS LAKE...
  QUAMBA...
  GRASSTON...
  BRAHAM...
  STANCHFIELD...
  GRANDY...
  ISANTI...
  BODUM...

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 4593 9314 4574 9314 4574 9300 4560 9300
      4541 9320 4542 9351 4573 9352 4593 9346
TIME...MOT...LOC 0031Z 269DEG 17KT 4584 9335 4565 9341
          4548 9352
WIND...HAIL 60MPH 0.75IN

$$

1 follow-up statement

653 
WWUS53 KMPX 020103
SVSMPX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
803 PM CDT TUE MAY 1 2012

MNC065-020118-
/O.CAN.KMPX.SV.W.0020.000000T0000Z-120502T0115Z/
KANABEC MN-
803 PM CDT TUE MAY 1 2012

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN KANABEC COUNTY IS
CANCELLED...

THE LINE OF STORMS WHICH PROMPTED THE WARNING HAVE MOVED OUT OF
THE WARNED AREA.

LAT...LON 4560 9300 4541 9320 4542 9351 4573 9330
      4573 9300
TIME...MOT...LOC 0103Z 269DEG 17KT 4584 9313 4565 9319
          4548 9330

$$

MNC025-059-020115-
/O.CON.KMPX.SV.W.0020.000000T0000Z-120502T0115Z/
CHISAGO MN-ISANTI MN-
803 PM CDT TUE MAY 1 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR ISANTI AND
NORTHWESTERN CHISAGO COUNTIES UNTIL 815 PM CDT...

AT 759 PM CDT...NATIONAL WEATHER SERVICE RADAR INDICATED A LINE OF
SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS OF 60 MPH. 
THESE STORMS WERE LOCATED ALONG A LINE EXTENDING FROM GRASSTON TO
GRANDY TO ISANTI...MOVING EAST AT 20 MPH. PENNY SIZE HAIL MAY ALSO
ACCOMPANY THESE DAMAGING WINDS.

LOCATIONS IMPACTED INCLUDE...
  CAMBRIDGE...STANCHFIELD...GRANDY...ISANTI...BODUM AND ATHENS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 60 MILES PER
HOUR...HAIL...AND DEADLY LIGHTNING. FOR YOUR PROTECTION MOVE TO AN
INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR HOME OR BUSINESS.

A TORNADO WATCH REMAINS IN EFFECT FOR THE WARNED AREA. TORNADOES CAN
DEVELOP QUICKLY FROM SEVERE THUNDERSTORMS. ALTHOUGH NOT IMMEDIATELY
LIKELY...IF A TORNADO IS SPOTTED ACT QUICKLY AND MOVE TO A PLACE OF
SAFETY INSIDE A STURDY STRUCTURE...SUCH AS A BASEMENT OR SMALL
INTERIOR ROOM.

&&

LAT...LON 4560 9300 4541 9320 4542 9351 4573 9330
      4573 9300
TIME...MOT...LOC 0103Z 269DEG 17KT 4584 9313 4565 9319
          4548 9330
WIND...HAIL 60MPH 0.75IN

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
May 1, 7:08 PM CDT	Severe Thunderstorm Warning	MPX	Sherburne, Stearns, Wright	52 min
May 1, 7:23 PM CDT	Special Weather Statement	MPX	Isanti, Kanabec	52 min
May 1, 7:24 PM CDT	Severe Thunderstorm Warning	MPX	Carver, McLeod, Sibley	51 min
May 1, 7:55 PM CDT	Special Weather Statement	MPX	Anoka	50 min
May 1, 8:08 PM CDT	Severe Thunderstorm Warning	MPX	Anoka, Chisago, Isanti	37 min
May 1, 8:09 PM CDT	Severe Thunderstorm Warning	MPX	Brown, Nicollet, Sibley	66 min
May 1, 8:13 PM CDT	Severe Thunderstorm Warning	MPX	Brown, Redwood	25 min
May 1, 9:24 PM CDT	Special Weather Statement	MPX	Nicollet, Sibley	51 min
May 1, 10:11 PM CDT	Special Weather Statement	MPX	Blue Earth, Faribault, Le Sueur, Martin, Nicollet	49 min
May 1, 11:12 PM CDT	Special Weather Statement	MPX	Freeborn, Rice, Steele, Waseca	48 min
May 2, 5:22 PM CDT	Severe Thunderstorm Warning	MPX	Blue Earth, Brown, Watonwan	53 min
May 2, 5:50 PM CDT	Tornado Warning	MPX	Blue Earth, Brown, Nicollet, Watonwan	40 min
May 2, 6:20 PM CDT	Severe Thunderstorm Warning	MPX	Blue Earth, Le Sueur, Nicollet, Waseca	55 min
May 2, 6:45 PM CDT	Severe Thunderstorm Warning	MPX	Goodhue, Rice, Steele	60 min
May 2, 6:45 PM CDT	Severe Thunderstorm Warning	MPX	Brown, Redwood	60 min
May 2, 6:58 PM CDT	Severe Thunderstorm Warning	MPX	Le Sueur, Rice, Steele, Waseca	47 min

Nearby

Severe Thunderstorm Warnings in Minnesota, 2012 Every 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.