Alert archive / Minnesota / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 98, NWS Grand Forks, ND

August 20, 2021Pennington County, Polk County, Red Lake County, Minnesota; Grand Forks County, Traill County, North Dakota

NWS Grand Forks, ND issued this severe thunderstorm warning at Aug 20, 2021, 5:13 PM CDT for Pennington County, Polk County, Red Lake County, Minnesota; Grand Forks County, Traill County, North Dakota. It was in force for 39 min. 2 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: Aug 20, 2021, 5:13 PM CDT (22:13 UTC)
Expired: Aug 20, 2021, 5:52 PM CDT
In force: 39 min
Issued by: NWS Grand Forks, ND
Area: Storm-based polygon
Damage threat: Considerable
Hail: 0.75 in
Wind: 70.0 mph

Counties Pennington County, MN, Polk County, MN, Red Lake County, MN, Grand Forks County, ND, Traill County, ND

The radar

The Fargo/Grand Forks radar (KMVX), 50 km from the middle of the area, began a volume at 22:15 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 20, 5:30 PM CDT	TSTM WND DMG	5 W Eldred, MN	LARGE ASH AND COTTONWOOD BRANCHES BLOWN DOWN IN A SHELTER BELT. TIME ESTIMATED BASED ON RADAR.
Aug 20, 5:30 PM CDT	TSTM WND DMG	5 W Eldred, MN	LARGE ASH AND COTTONWOOD BRANCHES BLOWN DOWN IN SHELTERBELT. TIME ESTIMATED BASED ON RADAR.

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.

Issued	Product	Office	Lasted
Aug 20, 2:24 PM CDT	Severe Thunderstorm Watch	SPC	8 hr

The nearest sounding before it

International Fa, MN (KINL), launched 12:00Z, 10.2 hours before the alert went out and 271 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: 347 J/kg
Mixed-layer CIN: -74 J/kg
Mixed-layer LCL: 1086 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 22 m²/s²
0-3 km storm-relative helicity: 13 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

300 
WUUS53 KFGF 202213
SVRFGF
MNC113-119-125-NDC035-097-202315-
/O.NEW.KFGF.SV.W.0098.210820T2213Z-210820T2315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Grand Forks ND
513 PM CDT Fri Aug 20 2021

The National Weather Service in Grand Forks has issued a

* Severe Thunderstorm Warning for...
  Northwestern Red Lake County in northwestern Minnesota...
  Western Polk County in northwestern Minnesota...
  Southwestern Pennington County in northwestern Minnesota...
  Southeastern Grand Forks County in northeastern North Dakota...
  Northeastern Traill County in southeastern North Dakota...

* Until 615 PM CDT.

* At 512 PM CDT, a severe thunderstorm was located near Climax, or 19
  miles south of Grand Forks, moving northeast at 45 mph.

  HAZARD...70 mph wind gusts.

  SOURCE...Trained weather spotters.

  IMPACT...Expect considerable tree damage. Damage is likely to 
           mobile homes, roofs, and outbuildings.

* This severe thunderstorm will be near...
  Climax around 515 PM CDT.
  Eldred around 520 PM CDT.
  Fisher and Bygland around 530 PM CDT.

Other locations in the path of this severe thunderstorm include
Davidson, Mallory and Key West.

This includes Interstate 29 between mile markers 106 and 126.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare immediately for damaging winds. People outside should move 
immediately to shelter inside a strong building. Stay away from 
windows.

&&

LAT...LON 4775 9640 4750 9682 4749 9686 4747 9686
      4736 9704 4763 9717 4817 9664 4806 9617
TIME...MOT...LOC 2212Z 210DEG 38KT 4763 9696 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH

$$

CJ

2 follow-up statements

687 
WWUS53 KFGF 202226
SVSFGF

Severe Weather Statement
National Weather Service Grand Forks ND
526 PM CDT Fri Aug 20 2021

MNC113-119-125-NDC035-097-202315-
/O.CON.KFGF.SV.W.0098.000000T0000Z-210820T2315Z/
Red Lake MN-Polk MN-Pennington MN-Grand Forks ND-Traill ND-
526 PM CDT Fri Aug 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 615 PM CDT
FOR NORTHWESTERN RED LAKE...WESTERN POLK...SOUTHWESTERN PENNINGTON...
SOUTHEASTERN GRAND FORKS AND NORTHEASTERN TRAILL COUNTIES...

At 526 PM CDT, a severe thunderstorm was located near Fisher, or 13
miles southeast of Grand Forks, moving northeast at 45 mph.

HAZARD...70 mph wind gusts.

SOURCE...Trained weather spotters.

IMPACT...Expect considerable tree damage. Damage is likely to mobile 
         homes, roofs, and outbuildings.

This severe storm will be near...
  Fisher around 530 PM CDT.

Other locations in the path of this severe thunderstorm include
Davidson, Mallory, Key West, Euclid, Sherack and Angus.

This includes Interstate 29 between mile markers 123 and 126.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

Intense thunderstorm lines can produce brief tornadoes and widespread
significant wind damage. Although a tornado is not immediately
likely, it is best to move to an interior room on the lowest floor of
a building. This storm may cause serious injury and significant
property damage.

&&

LAT...LON 4775 9640 4750 9682 4749 9686 4747 9686
      4744 9691 4770 9710 4817 9664 4806 9617
TIME...MOT...LOC 2226Z 210DEG 38KT 4776 9685 

TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH

$$

CJ

218 
WWUS53 KFGF 202252
SVSFGF

Severe Weather Statement
National Weather Service Grand Forks ND
552 PM CDT Fri Aug 20 2021

MNC113-119-125-NDC035-097-202302-
/O.CAN.KFGF.SV.W.0098.000000T0000Z-210820T2315Z/
Red Lake MN-Polk MN-Pennington MN-Grand Forks ND-Traill ND-
552 PM CDT Fri Aug 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN RED LAKE...
WESTERN POLK...SOUTHWESTERN PENNINGTON...SOUTHEASTERN GRAND FORKS AND
NORTHEASTERN TRAILL COUNTIES IS CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been cancelled.  However gusty winds are
still possible with this thunderstorm.

A Severe Thunderstorm Watch remains in effect until 1000 PM CDT for
northwestern Minnesota...and southeastern and northeastern North
Dakota.

LAT...LON 4775 9640 4750 9682 4749 9686 4747 9686
      4744 9691 4770 9710 4817 9664 4806 9617
TIME...MOT...LOC 2251Z 210DEG 38KT 4800 9664 

$$

CJ

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 20, 9:47 AM CDT	Special Weather Statement	FGF	Marshall, Pennington, Polk, Red Lake	28 min
Aug 20, 11:04 AM CDT	Areal Flood Advisory	FGF	Polk	4 hr
Aug 20, 12:28 PM CDT	Special Weather Statement	FGF	Norman, Polk	32 min
Aug 20, 1:02 PM CDT	Special Weather Statement	FGF	Pennington, Red Lake	28 min
Aug 20, 1:09 PM CDT	Severe Thunderstorm Warning	FGF	Pennington, Polk, Red Lake	51 min
Aug 20, 1:53 PM CDT	Severe Thunderstorm Warning	FGF	Beltrami, Clearwater, Lake of the Woods, Marshall, Pennington	67 min
Aug 20, 2:00 PM CDT	Special Weather Statement	FGF	Roseau	60 min
Aug 20, 2:52 PM CDT	Special Weather Statement	FGF	Lake of the Woods	53 min
Aug 20, 3:31 PM CDT	Special Weather Statement	FGF	Grant	59 min
Aug 20, 4:12 PM CDT	Special Weather Statement	FGF	Wadena	33 min
Aug 20, 4:19 PM CDT	Special Weather Statement	FGF	Beltrami	26 min
Aug 20, 4:20 PM CDT	Special Weather Statement	FGF	Beltrami	25 min
Aug 20, 4:22 PM CDT	Special Weather Statement	FGF	Clay	53 min
Aug 20, 4:43 PM CDT	Special Weather Statement	FGF	Beltrami	32 min
Aug 20, 4:49 PM CDT	Severe Thunderstorm Warning	FGF	Norman, Polk	26 min
Aug 20, 5:07 PM CDT	Severe Thunderstorm Warning	FGF	Otter Tail, Wadena	38 min
Aug 20, 11:12 AM CDT	Special Weather Statement	FGF	Cass	33 min
Aug 20, 2:43 PM CDT	Tornado Warning	FGF	Barnes, Cass	47 min
Aug 20, 3:24 PM CDT	Special Weather Statement	FGF	Cass	36 min
Aug 20, 3:49 PM CDT	Special Weather Statement	FGF	Griggs	56 min
Aug 20, 4:00 PM CDT	Special Weather Statement	FGF	Traill	60 min
Aug 20, 4:11 PM CDT	Tornado Warning	FGF	Barnes, Griggs, Steele	49 min
Aug 20, 4:13 PM CDT	Tornado Warning	FGF	Cass, Traill	47 min
Aug 20, 4:51 PM CDT	Special Weather Statement	FGF	Steele	54 min
Aug 20, 5:11 PM CDT	Special Weather Statement	FGF	Ramsey	49 min
Aug 20, 6:24 PM CDT	Special Weather Statement	FGF	Walsh	51 min

Nearby

Severe Thunderstorm Warnings in Minnesota, 2021 Severe Thunderstorm Warnings in North Dakota, 2021 Every severe thunderstorm warning 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.