Alert archive / Minnesota / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 232, NWS Twin Cities, MN

August 6, 2011Chisago County, Isanti County, Kanabec County, Minnesota

NWS Twin Cities, MN issued this severe thunderstorm warning at Aug 6, 2011, 1:20 PM CDT for Chisago County, Isanti County, Kanabec County, Minnesota. It was in force for 31 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 6, 2011, 1:20 PM CDT (18:20 UTC)
Expired: Aug 6, 2011, 1:51 PM CDT
In force: 31 min
Issued by: NWS Twin Cities, MN
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

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

The radar

The Minneapolis radar (KMPX), 108 km from the middle of the area, began a volume at 18:20 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
Aug 6, 1:29 PM CDT	HAIL 0.75	Ne Braham, MN	DELAYED REPORT. ESTIMATED TIME.

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, 6.3 hours before the alert went out and 109 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: 690 J/kg
Mixed-layer CIN: -28 J/kg
Mixed-layer LCL: 750 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 41 m²/s²
0-3 km storm-relative helicity: 51 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.6

Open this sounding in Storm Lab

The text

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

161 
WUUS53 KMPX 061820
SVRMPX
MNC025-059-065-061915-
/O.NEW.KMPX.SV.W.0232.110806T1820Z-110806T1915Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
120 PM CDT SAT AUG 6 2011

THE NATIONAL WEATHER SERVICE IN THE TWIN CITIES HAS ISSUED A

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

* UNTIL 215 PM CDT

* AT 115 PM CDT...RADAR INDICATED A SEVERE THUNDERSTORM...CAPABLE OF
  PRODUCING QUARTER SIZE HAIL AND DAMAGING WINDS IN EXCESS OF 60 MPH.
  THIS STORM WAS LOCATED 5 MILES WEST OF GRASSTON...OR ABOUT 7 MILES
  SOUTH OF MORA...AND MOVING EAST AT 25 MPH.

LOCATIONS IN THE WARNING INCLUDE...
  BRAHAM...
  GRASSTON...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

SEVERE THUNDERSTORMS CAN PRODUCE TORNADOES WITH LITTLE OR NO ADVANCE
WARNING. PREPARE TO MOVE TO A PLACE OF SAFETY IN A STURDY STRUCTURE
SUCH AS A BASEMENT OR SMALL INTERIOR ROOM IF A TORNADO IS SPOTTED.

&&

LAT...LON 4574 9313 4573 9285 4572 9285 4571 9287
      4567 9332 4574 9335 4576 9316 4591 9325
      4592 9314
TIME...MOT...LOC 1820Z 257DEG 20KT 4578 9322
WIND...HAIL 60MPH 1.00IN

$$

1 follow-up statement

819 
WWUS53 KMPX 061851
SVSMPX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
151 PM CDT SAT AUG 6 2011

MNC025-059-065-061905-
/O.CAN.KMPX.SV.W.0232.000000T0000Z-110806T1915Z/
CHISAGO MN-ISANTI MN-KANABEC MN-
151 PM CDT SAT AUG 6 2011

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL KANABEC...NORTH
CENTRAL ISANTI AND NORTHWESTERN CHISAGO COUNTIES IS CANCELLED...

THE STORM WHICH PROMPTED THE WARNING HAS MOVED OUT OF THE WARNED
AREA.

LAT...LON 4574 9313 4573 9285 4572 9285 4571 9287
      4567 9332 4574 9335 4576 9316 4591 9325
      4592 9314
TIME...MOT...LOC 1850Z 258DEG 20KT 4575 9297

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 5, 10:55 PM CDT	Areal Flood Advisory	MPX	Kandiyohi, Meeker, Sherburne, Wright	3 hr
Aug 6, 10:59 AM CDT	Areal Flood Advisory	MPX	Douglas, Mille Lacs, Morrison, Todd	4 hr
Aug 6, 11:59 AM CDT	Special Weather Statement	MPX	Morrison	61 min
Aug 6, 12:37 PM CDT	Severe Thunderstorm Warning	MPX	Benton, Isanti, Kanabec, Mille Lacs, Morrison	53 min
Aug 6, 2:35 PM CDT	Special Weather Statement	MPX	Anoka	25 min
Aug 6, 3:18 PM CDT	Special Weather Statement	MPX	Washington	27 min
Aug 6, 3:29 PM CDT	Severe Thunderstorm Warning	MPX	Ramsey, Washington	46 min
Aug 6, 5:36 PM CDT	Special Weather Statement	MPX	Douglas	24 min
Aug 6, 6:59 PM CDT	Special Weather Statement	MPX	Stearns	46 min

Nearby

Severe Thunderstorm Warnings in Minnesota, 2011 Every severe thunderstorm warning in 2011

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.