Alert archive / Minnesota / Tornado Warnings in 2021

Tornado Warning 7, NWS Grand Forks, ND

August 9, 2021Polk County, Minnesota

NWS Grand Forks, ND issued this tornado warning at Aug 9, 2021, 11:05 PM CDT for Polk County, Minnesota. It was in force for 25 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 9, 2021, 11:05 PM CDT (04:05 UTC)
Expired: Aug 9, 2021, 11:30 PM CDT
In force: 25 min
Issued by: NWS Grand Forks, ND
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 1.0 in

County Polk County, MN

The radar

The Fargo/Grand Forks radar (KMVX), 77 km from the middle of the area, began a volume at 04:07 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 9, 11:05 PM CDT	TORNADO 0	4 Se Key West, MN	A TORNADO TRACKED INTERMITTENTLY TO THE EAST-NORTHEAST FOR ROUGHLY 2 MILES TO AROUND 5SE KEY WEST BY 1109 PM CDT. THE TORNADO SNAPPED THE TOPS OFF OF SEVERAL ASH AND COTTONWOOD TREES AT TWO FARMSTEADS ALONG ITS PATH AND CRACKED A POWER POLE. PEAK WINDS ESTIMAT

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

International Fa, MN (KINL), launched 00:00Z, 4.1 hours before the alert went out and 250 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: 1281 J/kg
Mixed-layer CIN: -95 J/kg
Mixed-layer LCL: 1326 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 109 m²/s²
0-3 km storm-relative helicity: 220 m²/s²
Significant tornado parameter: 0.5
Supercell composite: 5.0

Open this sounding in Storm Lab

The text

As transmitted.

608 
WFUS53 KFGF 100405
TORFGF
MNC119-100430-
/O.NEW.KFGF.TO.W.0007.210810T0405Z-210810T0430Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Grand Forks ND
1105 PM CDT Mon Aug 9 2021

The National Weather Service in Grand Forks has issued a

* Tornado Warning for...
  Northwestern Polk County in northwestern Minnesota...

* Until 1130 PM CDT.
    
* At 1104 PM CDT, a severe thunderstorm capable of producing a
  tornado was located over Key West, or 15 miles east of Grand Forks,
  moving northeast at 35 mph.

  HAZARD...Tornado and quarter size hail.

  SOURCE...Radar indicated rotation.

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely.

* This dangerous storm will be near...
  Euclid around 1115 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 4810 9653 4805 9650 4803 9650 4802 9648
      4791 9648 4784 9675 4795 9683
TIME...MOT...LOC 0404Z 243DEG 30KT 4792 9673 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...1.00 IN

$$

Lynch

1 follow-up statement

701 
WWUS53 KFGF 100423
SVSFGF

Severe Weather Statement
National Weather Service Grand Forks ND
1123 PM CDT Mon Aug 9 2021

MNC119-100433-
/O.EXP.KFGF.TO.W.0007.000000T0000Z-210810T0430Z/
Polk MN-
1123 PM CDT Mon Aug 9 2021

...THE TORNADO WARNING FOR NORTHWESTERN POLK COUNTY WILL EXPIRE AT
1130 PM CDT...
    
The tornado threat has diminished and the Tornado Warning has been
cancelled. However, large hail and damaging winds remain likely and a
Severe Thunderstorm Warning remains in effect for the area.  However
gusty winds are still possible with this thunderstorm.

Remember, a Severe Thunderstorm Warning still remains in effect for
portions of Polk County.

LAT...LON 4810 9653 4805 9650 4803 9650 4802 9648
      4791 9648 4784 9675 4795 9683
TIME...MOT...LOC 0423Z 243DEG 30KT 4799 9653 

$$

Lynch

The office that day

Everything else NWS Grand Forks, ND issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 9, 9:54 PM CDT	Severe Thunderstorm Warning Considerable damage threat	FGF	Polk	66 min
Aug 9, 10:42 PM CDT	Severe Thunderstorm Warning Considerable damage threat	FGF	Norman, Pennington, Polk, Red Lake	63 min
Aug 9, 11:29 PM CDT	Severe Thunderstorm Warning Considerable damage threat	FGF	Marshall, Pennington, Polk, Red Lake	61 min
Aug 10, 2:20 AM CDT	Special Weather Statement	FGF	Lake of the Woods	25 min
Aug 10, 2:55 AM CDT	Special Weather Statement	FGF	Lake of the Woods	35 min

Nearby

Tornado Warnings in Minnesota, 2021 Every tornado warning in 2021 Tornadoes in 2021

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.