Alert archive / Minnesota / Severe Thunderstorm Warnings in 2007

Severe Thunderstorm Warning 14, NWS Twin Cities, MN

April 21, 2007Stevens County, Minnesota

NWS Twin Cities, MN issued this severe thunderstorm warning at Apr 21, 2007, 9:27 PM CDT for Stevens County, Minnesota. It was in force for 33 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
Apr 21, 2007, 9:27 PM CDT (02:27 UTC)
Expired
Apr 21, 2007, 10:00 PM CDT
In force
33 min
Issued by
NWS Twin Cities, MN
Area
Counties, with a storm outline in the text

County Stevens County, MN

The radar

The Aberdeen radar (KABR), 192 km from the middle of the area, began a volume at 02:29 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 nearest sounding before it

Minneapolis, MN (KMPX), launched 00:00Z, 2.5 hours before the alert went out and 204 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 2007-04-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 16 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Minneapolis, MN at 00:00Z on 2007-04-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 146 square meters per square second.193958Sfc1 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
16 J/kg
Mixed-layer CIN
-307 J/kg
Mixed-layer LCL
2804 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
146 m²/s²
0-3 km storm-relative helicity
290 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.4

Open this sounding in Storm Lab

The text

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

000 
WUUS53 KMPX 220229
SVRMPX
MNC149-220300-
/O.NEW.KMPX.SV.W.0014.070422T0227Z-070422T0300Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
927 PM CDT SAT APR 21 2007

THE NATIONAL WEATHER SERVICE IN THE TWIN CITIES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  STEVENS COUNTY IN WEST CENTRAL MINNESOTA...

* UNTIL 1000 PM CDT

* AT 923 PM CDT...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM...   
  CAPABLE OF PRODUCING NICKEL SIZED HAIL. THIS STORM WAS LOCATED 3   
  MILES SOUTHWEST OF MORRIS...OR ABOUT OVER MORRIS...AND MOVING      
  NORTHEAST AT 25 MPH.

* LOCATIONS IMPACTED INCLUDE...
  DONNELLY...

HAIL UP TO THE SIZE OF A DIME HAS BEEN REPORTED WEST OF MORRIS WITH 
THIS STORM.

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 4554 9611 4546 9588 4566 9576 4573 9585
      4575 9607

$$

LS
2 follow-up statements
000 
WWUS53 KMPX 220237
SVSMPX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
937 PM CDT SAT APR 21 2007

MNC149-220300-
/O.CON.KMPX.SV.W.0014.000000T0000Z-070422T0300Z/
STEVENS MN-
937 PM CDT SAT APR 21 2007

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1000 PM CDT
FOR STEVENS COUNTY...

AT 925 PM...DIME SIZE HAIL WAS REPORTED IN MORRIS WITH THIS STORM.

AT 935 PM CDT...DOPPLER RADAR CONTINUED TO INDICATE A SEVERE
THUNDERSTORM...CAPABLE OF PRODUCING LARGE HAIL.  THIS STORM WAS
LOCATED NEAR MORRIS...OR ABOUT 8 MILES WEST OF CYRUS...AND MOVING
NORTHEAST AT 25 MPH.

OTHER LOCATIONS IN THE WARNING INCLUDE DONNELLY...CHOKIO AND ALBERTA.

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD
TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

LAT...LON 4555 9623 4546 9588 4566 9576 4573 9585
      4575 9622

$$

LS
000 
WWUS53 KMPX 220259
SVSMPX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
958 PM CDT SAT APR 21 2007

MNC149-220308-
/O.EXP.KMPX.SV.W.0014.000000T0000Z-070422T0300Z/
STEVENS MN-
958 PM CDT SAT APR 21 2007

...THE SEVERE THUNDERSTORM WARNING FOR STEVENS COUNTY EXPIRES AT 1000
PM CDT...

SEVERE STORMS WERE ABOUT TO MOVE OUT OF THE COUNTY. HOWEVER...MORE
THUNDERSTORMS WERE DEVELOPING IN THE AREA...REMAIN ALERT FOR POSSIBLE
ADDITIONAL WARNINGS.

HAIL UP TO THE SIZE OF A DIME WAS REPORTED WEST OF MORRIS AT 925 PM 
CDT WITH THIS STORM.

LAT...LON 4555 9623 4546 9588 4566 9576 4573 9585
      4575 9622

$$

LS

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 21, 9:51 PM CDTSevere Thunderstorm WarningMPXLac qui Parle24 min
Apr 21, 9:51 PM CDTSevere Thunderstorm WarningMPXLac qui Parle24 min
Apr 21, 10:14 PM CDTSevere Thunderstorm WarningMPXStevens31 min
Apr 21, 10:52 PM CDTSevere Thunderstorm WarningMPXDouglas23 min
Apr 21, 10:58 PM CDTSevere Thunderstorm WarningMPXLac qui Parle19 min

Nearby

Severe Thunderstorm Warnings in Minnesota, 2007Every severe thunderstorm warning in 2007

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.