Alert archive / Minnesota / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 97, NWS Grand Forks, ND

August 20, 2021Otter Tail County, Wadena County, Minnesota

NWS Grand Forks, ND issued this severe thunderstorm warning at Aug 20, 2021, 5:07 PM CDT for Otter Tail County, Wadena County, Minnesota. It was in force for 38 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, 5:07 PM CDT (22:07 UTC)
Expired: Aug 20, 2021, 5:45 PM CDT
In force: 38 min
Issued by: NWS Grand Forks, ND
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Otter Tail County, MN, Wadena County, MN

The radar

The Fargo/Grand Forks radar (KMVX), 199 km from the middle of the area, began a volume at 22:08 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, 5:25 PM CDT	TSTM WND DMG	2 N Almora, MN	LARGE TREE BLOWN DOWN. TIME ESTIMATED ASED ON RADAR.
Aug 20, 5:25 PM CDT	TSTM WND DMG	2 N Almora, MN	LARGE TREE BLOWN DOWN. 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

Minneapolis, MN (KMPX), launched 12:00Z, 10.1 hours before the alert went out and 217 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: 48 J/kg
Mixed-layer CIN: -139 J/kg
Mixed-layer LCL: 999 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 62 m²/s²
0-3 km storm-relative helicity: 37 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

505 
WUUS53 KFGF 202207
SVRFGF
MNC111-159-202245-
/O.NEW.KFGF.SV.W.0097.210820T2207Z-210820T2245Z/

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

The National Weather Service in Grand Forks has issued a

* Severe Thunderstorm Warning for...
  Southwestern Wadena County in central Minnesota...
  Eastern Otter Tail County in west central Minnesota...

* Until 545 PM CDT.

* At 506 PM CDT, a severe thunderstorm was located over Parkers
  Prairie, or 36 miles east of Fergus Falls, moving north 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...
  Almora around 520 PM CDT.
  Wrightstown and Henning around 525 PM CDT.

Other locations in the path of this severe thunderstorm include Deer
Creek, Bluffton, Wadena and New York Mills.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4671 9540 4671 9504 4637 9514 4637 9516
      4633 9515 4611 9522 4611 9551
TIME...MOT...LOC 2206Z 190DEG 37KT 4612 9535 

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

$$

Lee

2 follow-up statements

873 
WWUS53 KFGF 202228
SVSFGF

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

MNC111-159-202245-
/O.CON.KFGF.SV.W.0097.000000T0000Z-210820T2245Z/
Wadena MN-Otter Tail MN-
528 PM CDT Fri Aug 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 545 PM CDT
FOR SOUTHWESTERN WADENA AND EASTERN OTTER TAIL COUNTIES...

At 528 PM CDT, a severe thunderstorm was located near Almora, or 35
miles east of Fergus Falls, moving north at 35 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
  Deer Creek, Wadena, Bluffton and New York Mills.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4671 9540 4671 9504 4637 9514 4637 9516
      4633 9515 4611 9522 4611 9551
TIME...MOT...LOC 2228Z 193DEG 30KT 4630 9532 

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

$$

Lee

742 
WWUS53 KFGF 202242
SVSFGF

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

MNC111-159-202251-
/O.EXP.KFGF.SV.W.0097.000000T0000Z-210820T2245Z/
Wadena MN-Otter Tail MN-
542 PM CDT Fri Aug 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN WADENA AND
EASTERN OTTER TAIL COUNTIES WILL EXPIRE AT 545 PM CDT...
                
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 will be allowed to expire.

A Severe Thunderstorm Watch remains in effect until 1000 PM CDT for
central and west central Minnesota.

LAT...LON 4671 9540 4671 9504 4637 9514 4637 9516
      4633 9515 4611 9522 4611 9551
TIME...MOT...LOC 2241Z 190DEG 37KT 4641 9529 

$$

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, 5:13 PM CDT	Severe Thunderstorm Warning Considerable damage threat	FGF	Pennington, Polk, Red Lake	39 min

Nearby

Severe Thunderstorm Warnings in Minnesota, 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.