Alert archive / Minnesota / Tornado Warnings in 2011

Tornado Warning 14, NWS Twin Cities, MN

May 21, 2011Anoka County, Minnesota

NWS Twin Cities, MN issued this tornado warning at May 21, 2011, 7:25 PM CDT for Anoka County, Minnesota. It was in force for 35 min. 3 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
May 21, 2011, 7:25 PM CDT (00:25 UTC)
Expired
May 21, 2011, 8:00 PM CDT
In force
35 min
Issued by
NWS Twin Cities, MN
Area
Storm-based polygon

County Anoka County, MN

The radar

The Minneapolis radar (KMPX), 54 km from the middle of the area, began a volume at 00:26 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
May 21, 7:27 PM CDTHAIL 0.25Anoka, MNDIME SIZE
May 21, 7:47 PM CDTFUNNEL CLOUDEast Bethel, MNROTATING WALL CLOUD
May 21, 7:48 PM CDTFUNNEL CLOUDHam Lake, MNROTATING WALL CLOUD

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 00:00Z, 0.4 hours before the alert went out and 55 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 2011-05-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1091 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 2011-05-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 348 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
1091 J/kg
Mixed-layer CIN
-11 J/kg
Mixed-layer LCL
922 m above ground
0-6 km bulk shear
55 kt
0-1 km storm-relative helicity
348 m²/s²
0-3 km storm-relative helicity
424 m²/s²
Significant tornado parameter
2.3
Supercell composite
12.8

Open this sounding in Storm Lab

The text

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

577 
WFUS53 KMPX 220025
TORMPX
MNC003-220100-
/O.NEW.KMPX.TO.W.0014.110522T0025Z-110522T0100Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
725 PM CDT SAT MAY 21 2011

THE NATIONAL WEATHER SERVICE IN THE TWIN CITIES HAS ISSUED A

* TORNADO WARNING FOR...
  ANOKA COUNTY IN EAST CENTRAL MINNESOTA...

* UNTIL 800 PM CDT

* AT 723 PM CDT...RADAR WAS TRACKING A SEVERE STORM WITH STRONG
  ROTATION. THE MOST DANGEROUS PART OF THE STORM WAS 2 MILES NORTH OF
  COON RAPIDS...AND MOVING NORTH AT 20 MPH. IN ADDITION...TRAINED 
  SPOTTERS AROUND THE ANDOVER HAVE BEEN OBSERVING A ROTATING WALL 
  CLOUD...WHICH PRODUCED A BRIEF TORNADO NEAR MEDINA EARLIER  
  TONIGHT. 

* LOCATIONS IN THE WARNING INCLUDE...
  ANDOVER...
  HAM LAKE...
  CEDAR...
  EAST BETHEL...

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 4540 9334 4532 9302 4513 9326 4521 9341
TIME...MOT...LOC 0024Z 198DEG 17KT 4521 9330

$$

JLT
3 follow-up statements
361 
WWUS53 KMPX 220035
SVSMPX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
735 PM CDT SAT MAY 21 2011

MNC003-220100-
/O.CON.KMPX.TO.W.0014.000000T0000Z-110522T0100Z/
ANOKA MN-
735 PM CDT SAT MAY 21 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR ANOKA COUNTY UNTIL 800 PM
CDT...

AT 732 PM CDT...NATIONAL WEATHER SERVICE RADAR INDICATED A SEVERE
THUNDERSTORM CAPABLE OF PRODUCING A TORNADO.  THIS DANGEROUS STORM
WAS LOCATED NEAR HAM LAKE...OR 14 MILES WEST OF FOREST LAKE...MOVING 
NORTHEAST AT 20 MPH. IN ADDITION...TRAINED SPOTTERS HAVE BEEN 
REPORTING UP TO QUARTER SIZE HAIL FROM THIS SEVERE STORM NEAR 
ANOKA...ANDOVER AND COON RAPIDS. 

LOCATIONS IMPACTED INCLUDE...
  CEDAR...HAM LAKE AND EAST BETHEL.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TO REPORT SEVERE WEATHER...CONTACT YOUR NEAREST LAW ENFORCEMENT
AGENCY. THEY WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE
IN THE TWIN CITIES.

&&

LAT...LON 4540 9334 4532 9302 4513 9326 4521 9341
TIME...MOT...LOC 0034Z 216DEG 18KT 4525 9325

$$

JLT
872 
WWUS53 KMPX 220048
SVSMPX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
748 PM CDT SAT MAY 21 2011

MNC003-220100-
/O.CON.KMPX.TO.W.0014.000000T0000Z-110522T0100Z/
ANOKA MN-
748 PM CDT SAT MAY 21 2011

...A TORNADO WARNING REMAINS IN EFFECT FOR ANOKA COUNTY UNTIL 800 PM
CDT...

AT 746 PM CDT...TRAINED WEATHER SPOTTERS REPORTED A ROTATING WALL 
CLOUD NEAR HAM LAKE AND EAST BETHEL...OR 11 MILES WEST OF FOREST 
LAKE...MOVING NORTHEAST AT 20 MPH.

LOCATIONS IMPACTED INCLUDE...
  EAST BETHEL.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOTORISTS SHOULD NOT TAKE SHELTER UNDER HIGHWAY OVERPASSES. AS A LAST
RESORT... EITHER PARK YOUR VEHICLE AND STAY PUT...OR ABANDON YOUR
VEHICLE AND LIE DOWN IN A LOW LYING AREA.

TO REPORT SEVERE WEATHER...CONTACT YOUR NEAREST LAW ENFORCEMENT
AGENCY. THEY WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE
IN THE TWIN CITIES.

&&

LAT...LON 4540 9334 4532 9302 4513 9326 4521 9341
TIME...MOT...LOC 0047Z 216DEG 18KT 4530 9320

$$

JLT
748 
WWUS53 KMPX 220059
SVSMPX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
759 PM CDT SAT MAY 21 2011

MNC003-220114-
/O.EXP.KMPX.TO.W.0014.000000T0000Z-110522T0100Z/
ANOKA MN-
759 PM CDT SAT MAY 21 2011

...THE TORNADO WARNING FOR ANOKA COUNTY WILL EXPIRE AT 800 PM CDT...

THE STORM WHICH PROMPTED THE WARNING HAS MOVED OUT OF THE WARNED
AREA...HOWEVER SMALL HAIL IS STILL POSSIBLE WITH THIS THUNDERSTORM.

TO REPORT SEVERE WEATHER...CONTACT YOUR NEAREST LAW ENFORCEMENT
AGENCY. THEY WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE
IN THE TWIN CITIES.

LAT...LON 4540 9334 4532 9302 4513 9326 4521 9341
TIME...MOT...LOC 0059Z 216DEG 18KT 4535 9315

$$

The office that day

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

IssuedProductOfficeCountiesLasted
May 21, 7:00 PM CDTTornado WarningMPXAnoka, Hennepin45 min
May 21, 7:24 PM CDTSevere Thunderstorm WarningMPXHennepin, Wright51 min
May 21, 7:46 PM CDTSpecial Weather StatementMPXPope44 min
May 21, 8:00 PM CDTAreal Flood AdvisoryMPXAnoka, Hennepin, Wright3 hr
May 21, 8:06 PM CDTSevere Thunderstorm WarningMPXMartin39 min
May 21, 8:44 PM CDTSevere Thunderstorm WarningMPXMartin61 min
May 21, 8:59 PM CDTSpecial Weather StatementMPXTodd61 min
May 21, 9:11 PM CDTSevere Thunderstorm WarningMPXTodd64 min
May 21, 9:25 PM CDTSevere Thunderstorm WarningMPXWatonwan50 min
May 21, 9:42 PM CDTSevere Thunderstorm WarningMPXRedwood48 min
May 21, 10:12 PM CDTSpecial Weather StatementMPXYellow Medicine48 min
May 21, 10:26 PM CDTSpecial Weather StatementMPXRedwood34 min
May 21, 10:43 PM CDTSevere Thunderstorm WarningMPXBrown, Martin, Redwood, Watonwan62 min
May 21, 10:43 PM CDTSevere Thunderstorm WarningMPXChippewa, Pope, Renville, Stevens, Swift47 min
May 22, 12:46 AM CDTSpecial Weather StatementMPXLe Sueur, Rice, Steele, Waseca44 min
May 22, 10:57 AM CDTSpecial Weather StatementMPXDakota, Goodhue, Rice48 min
May 22, 11:02 AM CDTSpecial Weather StatementMPXAnoka, Hennepin, Ramsey43 min
May 22, 12:38 PM CDTSevere Thunderstorm WarningMPXLe Sueur, Rice, Steele, Waseca52 min
May 22, 12:53 PM CDTSevere Thunderstorm WarningMPXCarver, Le Sueur, Scott52 min
May 22, 1:23 PM CDTSevere Thunderstorm WarningMPXDakota, Goodhue, Rice, Steele67 min
May 22, 1:35 PM CDTSpecial Weather StatementMPXHennepin40 min
May 22, 2:05 PM CDTSevere Thunderstorm WarningMPXGoodhue40 min
May 22, 2:10 PM CDTTornado WarningMPXAnoka, Hennepin, Ramsey35 min
May 22, 2:24 PM CDTTornado WarningMPXAnoka, Hennepin, Ramsey36 min
May 22, 2:45 PM CDTTornado WarningMPXAnoka, Ramsey, Washington30 min
May 22, 3:10 PM CDTTornado WarningMPXChisago, Washington35 min
May 22, 3:34 PM CDTTornado WarningMPXChisago41 min

Nearby

Tornado Warnings in Minnesota, 2011Every tornado warning in 2011Tornadoes 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.