Alert archive / Minnesota / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 94, NWS Grand Forks, ND

August 20, 2021Pennington County, Polk County, Red Lake County, Minnesota

NWS Grand Forks, ND issued this severe thunderstorm warning at Aug 20, 2021, 1:09 PM CDT for Pennington County, Polk County, Red Lake County, Minnesota. It was in force for 51 min. 4 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, 1:09 PM CDT (18:09 UTC)
Expired: Aug 20, 2021, 2:00 PM CDT
In force: 51 min
Issued by: NWS Grand Forks, ND
Area: Storm-based polygon
Tornado: Possible
Hail: 0.75 in
Wind: 60.0 mph

Counties Pennington County, MN, Polk County, MN, Red Lake County, MN

The radar

The Fargo/Grand Forks radar (KMVX), 111 km from the middle of the area, began a volume at 18:10 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, 1:16 PM CDT	TSTM WND DMG	4 E Hazel, MN	FAUL ASK AND PINE TREES BROKEN DOWN IN A SHELTER BELT. PHOTO AND REPORT POSTED VIA SOCIAL MEDIA. TIME ESTIMATED BASED ON RADAR
Aug 20, 1:16 PM CDT	TSTM WND DMG	4 E Hazel, MN	FOUR ASH AND PINE TREES BROKEN DOWN IN A SHELTER BELT. PHOTO AND REPORT POSTED VIA SOCIAL MEDIA. TIME ESTIMATED BASED ON RADAR
Aug 20, 1:16 PM CDT	TSTM WND DMG	4 E Hazel, MN	PICTURE RECEIVED OF TREES DOWN VIA SOCIAL MEDIA. TIME ESTIMATED FROM RADAR.
Aug 20, 1:55 PM CDT	TSTM WND DMG	5 Ese High Landing, MN	TIN ROOF PANEL BLOWN OFF A SHED.

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 12:00Z, 6.2 hours before the alert went out and 213 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.

325 
WUUS53 KFGF 201809
SVRFGF
MNC113-119-125-201900-
/O.NEW.KFGF.SV.W.0094.210820T1809Z-210820T1900Z/

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

The National Weather Service in Grand Forks has issued a

* Severe Thunderstorm Warning for...
  Eastern Red Lake County in northwestern Minnesota...
  Southeastern Polk County in northwestern Minnesota...
  Eastern Pennington County in northwestern Minnesota...

* Until 200 PM CDT.

* At 108 PM CDT, a severe thunderstorm was located near Mentor, or 32
  miles south of Thief River Falls, moving northeast at 40 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* This severe thunderstorm will be near...
  Mentor around 110 PM CDT.
  Erskine around 115 PM CDT.

Other locations in the path of this severe thunderstorm include
Brooks, Oklee, Plummer and Roland.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4750 9600 4750 9613 4762 9624 4817 9603
      4803 9567 4775 9558 4767 9558 4767 9555
TIME...MOT...LOC 1808Z 213DEG 34KT 4764 9611 

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

$$

CJ

1 follow-up statement

797 
WWUS53 KFGF 201833
SVSFGF

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

MNC113-119-125-201900-
/O.CON.KFGF.SV.W.0094.000000T0000Z-210820T1900Z/
Red Lake MN-Polk MN-Pennington MN-
133 PM CDT Fri Aug 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 200 PM CDT
FOR EASTERN RED LAKE...SOUTHEASTERN POLK AND EASTERN PENNINGTON
COUNTIES...

At 132 PM CDT, a severe thunderstorm was located near Oklee, or 22
miles southeast of Thief River Falls, moving northeast at 40 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
  Oklee, Roland and High Landing.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

&&

LAT...LON 4754 9599 4796 9611 4817 9603 4803 9567
      4775 9558 4767 9558 4767 9555 4756 9583
TIME...MOT...LOC 1832Z 213DEG 34KT 4783 9592 

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	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, 1:53 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, 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.