Alert archive / Minnesota / Severe Thunderstorm Warnings in 2007

Severe Thunderstorm Warning 17, NWS Twin Cities, MN

April 21, 2007Stevens County, Minnesota

NWS Twin Cities, MN issued this severe thunderstorm warning at Apr 21, 2007, 10:14 PM CDT for Stevens 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
Apr 21, 2007, 10:14 PM CDT (03:14 UTC)
Expired
Apr 21, 2007, 10:45 PM CDT
In force
31 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), 182 km from the middle of the area, began a volume at 03:13 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
Apr 21, 10:34 PM CDTHAIL 0.882 W Morris, MN

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.

IssuedProductOfficeLasted
Apr 21, 9:31 PM CDTSevere Thunderstorm WatchSPC4 hr

The nearest sounding before it

Aberdeen, SD (KABR), launched 00:00Z, 3.2 hours before the alert went out and 194 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, Aberdeen, SD at 00:00Z on 2007-04-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1323 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, Aberdeen, SD at 00:00Z on 2007-04-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 1 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
1323 J/kg
Mixed-layer CIN
-6 J/kg
Mixed-layer LCL
965 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
1 m²/s²
0-3 km storm-relative helicity
265 m²/s²
Significant tornado parameter
0.8
Supercell composite
4.6

Open this sounding in Storm Lab

The text

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

000 
WUUS53 KMPX 220316
SVRMPX
MNC149-220345-
/O.NEW.KMPX.SV.W.0017.070422T0314Z-070422T0345Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1014 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 1045 PM CDT

* AT 1013 PM CDT...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM...
  CAPABLE OF PRODUCING LARGE HAIL.  THIS STORM WAS LOCATED 6 MILES
  SOUTH OF CHOKIO...OR ABOUT 13 MILES SOUTHWEST OF MORRIS...AND
  MOVING NORTHEAST AT 45 MPH.

* LOCATIONS IMPACTED INCLUDE...
  CHOKIO...
  MORRIS...
  DONNELLY...

HAIL UP TO ONE INCH IN DIAMETER HAS BEEN REPORTED SIX MILES WEST OF 
BELLINGHAM 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.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 200 AM CDT SUNDAY
MORNING FOR WEST CENTRAL MINNESOTA. 

LAT...LON 4544 9621 4542 9608 4555 9575 4575 9602 4557 9625

$$

LS
2 follow-up statements
000 
WWUS53 KMPX 220328
SVSMPX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1028 PM CDT SAT APR 21 2007

MNC149-220345-
/O.CON.KMPX.SV.W.0017.000000T0000Z-070422T0345Z/
STEVENS MN-
1028 PM CDT SAT APR 21 2007

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1045 PM CDT
FOR STEVENS COUNTY...

AT 1025 PM CDT...DOPPLER RADAR CONTINUED TO INDICATE A SEVERE
THUNDERSTORM...CAPABLE OF PRODUCING LARGE HAIL.  THIS STORM WAS
LOCATED 3 MILES SOUTH OF ALBERTA...OR ABOUT 6 MILES SOUTHEAST OF
CHOKIO...AND MOVING NORTHEAST AT 45 MPH.

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

THIS STORM HAS A HISTORY OF PRODUCING LARGE HAIL. SEEK SHELTER NOW 
INSIDE A STURDY STRUCTURE AND STAY AWAY FROM WINDOWS

LAT...LON 4551 9624 4542 9608 4565 9575 4572 9582
      4575 9602

$$

LS
000 
WWUS53 KMPX 220344
SVSMPX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1044 PM CDT SAT APR 21 2007

MNC149-220354-
/O.EXP.KMPX.SV.W.0017.000000T0000Z-070422T0345Z/
STEVENS MN-
1044 PM CDT SAT APR 21 2007

...THE SEVERE THUNDERSTORM WARNING FOR STEVENS COUNTY EXPIRES AT 1045
PM CDT...

AT 1034 PM CDT...HAIL UP TO THE SIZE OF A NICKEL WAS REPORTED TWO 
MILES WEST OF MORRIS WITH THE STORM.

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

LAT...LON 4551 9624 4542 9608 4565 9575 4572 9582
      4575 9602

$$

LS

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 21, 9:27 PM CDTSevere Thunderstorm WarningMPXStevens33 min
Apr 21, 9:51 PM CDTSevere Thunderstorm WarningMPXLac qui Parle24 min
Apr 21, 9:51 PM CDTSevere Thunderstorm WarningMPXLac qui Parle24 min
Apr 21, 10:52 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.