Alert archive / Minnesota / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 96, NWS Grand Forks, ND

August 20, 2021Traill County, North Dakota; Norman County, Polk County, Minnesota

NWS Grand Forks, ND issued this severe thunderstorm warning at Aug 20, 2021, 4:49 PM CDT for Traill County, North Dakota; Norman County, Polk County, Minnesota. It was in force for 26 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, 4:49 PM CDT (21:49 UTC)
Expired: Aug 20, 2021, 5:15 PM CDT
In force: 26 min
Issued by: NWS Grand Forks, ND
Area: Storm-based polygon
Tornado: Possible
Hail: 0.75 in
Wind: 60.0 mph

Counties Norman County, MN, Polk County, MN, Traill County, ND

The radar

The Fargo/Grand Forks radar (KMVX), 21 km from the middle of the area, began a volume at 21:50 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, 5:05 PM CDT	TSTM WND GST 70	1 S Cummings, ND	SPOTTER ESTIMATED WIND GUST OF 70 MPH ON I-29 SOUTH OF CUMMINGS ND. SPOTTERS CAR OSCILLATING/VIBRATING AND NEARBY SEMI STRUGGLED TO REMAIN UPRIGHT.
Aug 20, 5:05 PM CDT	TSTM WND GST 70	1 W Cummings, ND

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

Bismarck Municip, ND (KBIS), launched 12:00Z, 9.8 hours before the alert went out and 287 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: 306 J/kg
Mixed-layer CIN: -14 J/kg
Mixed-layer LCL: 609 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 163 m²/s²
0-3 km storm-relative helicity: 141 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.6

Open this sounding in Storm Lab

The text

As transmitted.

256 
WUUS53 KFGF 202149
SVRFGF
MNC107-119-NDC097-202215-
/O.NEW.KFGF.SV.W.0096.210820T2149Z-210820T2215Z/

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

The National Weather Service in Grand Forks has issued a

* Severe Thunderstorm Warning for...
  Northwestern Norman County in northwestern Minnesota...
  Southwestern Polk County in northwestern Minnesota...
  Central Traill County in southeastern North Dakota...

* Until 515 PM CDT.

* At 449 PM CDT, a severe thunderstorm was located near Kelso, or 35
  miles north of Fargo, moving northeast at 45 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* This severe thunderstorm will be near...
  Kelso around 450 PM CDT.
  Hillsboro around 455 PM CDT.
  Cummings and Caledonia around 505 PM CDT.

Other locations in the path of this severe thunderstorm include
Shelly and Nielsville.

This includes Interstate 29 between mile markers 93 and 122.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4767 9715 4767 9689 4750 9677 4724 9701
      4724 9735
TIME...MOT...LOC 2149Z 209DEG 38KT 4734 9711 

TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

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	Grand Forks	28 min
Aug 20, 11:04 AM CDT	Areal Flood Advisory	FGF	Grand Forks	4 hr
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, 5:13 PM CDT	Severe Thunderstorm Warning Considerable damage threat	FGF	Grand Forks, Traill	39 min
Aug 20, 6:24 PM CDT	Special Weather Statement	FGF	Walsh	51 min
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, 5:07 PM CDT	Severe Thunderstorm Warning	FGF	Otter Tail, Wadena	38 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.