Alert archive / Minnesota / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 108, NWS Grand Forks, ND

September 6, 2021Mahnomen County, Norman County, Minnesota

NWS Grand Forks, ND issued this severe thunderstorm warning at Sep 6, 2021, 9:50 PM CDT for Mahnomen County, Norman County, Minnesota. It was in force for 20 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Sep 6, 2021, 9:50 PM CDT (02:50 UTC)
Expired: Sep 6, 2021, 10:10 PM CDT
In force: 20 min
Issued by: NWS Grand Forks, ND
Area: Storm-based polygon
Hail: 1.0 in
Wind: 50.0 mph

Counties Mahnomen County, MN, Norman County, MN

The radar

The Fargo/Grand Forks radar (KMVX), 94 km from the middle of the area, began a volume at 02:52 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.

The nearest sounding before it

International Fa, MN (KINL), launched 00:00Z, 2.8 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: 133 J/kg
Mixed-layer CIN: -170 J/kg
Mixed-layer LCL: 1566 m above ground
0-6 km bulk shear: 64 kt
0-1 km storm-relative helicity: 364 m²/s²
0-3 km storm-relative helicity: 441 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted.

996 
WUUS53 KFGF 070250
SVRFGF
MNC087-107-070330-
/O.NEW.KFGF.SV.W.0108.210907T0250Z-210907T0330Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Grand Forks ND
950 PM CDT Mon Sep 6 2021

The National Weather Service in Grand Forks has issued a

* Severe Thunderstorm Warning for...
  Northeastern Norman County in northwestern Minnesota...
  Central Mahnomen County in northwestern Minnesota...

* Until 1030 PM CDT.

* At 949 PM CDT, a severe thunderstorm was located near Gary, or 40
  miles northeast of Fargo, moving east at 45 mph.

  HAZARD...Quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Damage to vehicles is expected.

* This severe thunderstorm will be near...
  Gary around 955 PM CDT.
  Waukon and Faith around 1005 PM CDT.

Other locations in the path of this severe thunderstorm include
Mahnomen, Bejou, Beaulieu, Island Lake in Mahnomen County, Pine Bend
and Mahkonce.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Large hail and damaging winds and 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.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4725 9645 4742 9647 4749 9557 4727 9557
TIME...MOT...LOC 0249Z 264DEG 40KT 4735 9635 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH

$$

BH

1 follow-up statement

809 
WWUS53 KFGF 070310
SVSFGF

Severe Weather Statement
National Weather Service Grand Forks ND
1010 PM CDT Mon Sep 6 2021

MNC087-107-070320-
/O.CAN.KFGF.SV.W.0108.000000T0000Z-210907T0330Z/
Norman MN-Mahnomen MN-
1010 PM CDT Mon Sep 6 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN NORMAN AND
CENTRAL MAHNOMEN 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 small hail and
heavy rain are still possible with this thunderstorm.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Grand Forks.

LAT...LON 4725 9645 4742 9647 4749 9557 4727 9557
TIME...MOT...LOC 0309Z 264DEG 40KT 4737 9600 

$$

BH

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 6, 9:06 PM CDT	Special Weather Statement	FGF	Beltrami	24 min
Sep 6, 9:17 PM CDT	Severe Thunderstorm Warning	FGF	Beltrami	18 min
Sep 6, 10:32 PM CDT	Special Weather Statement	FGF	Hubbard	43 min
Sep 6, 11:19 PM CDT	Special Weather Statement	FGF	Mahnomen	41 min
Sep 6, 11:30 PM CDT	Severe Thunderstorm Warning	FGF	Becker, Clearwater, Mahnomen	45 min
Sep 7, 12:07 AM CDT	Severe Thunderstorm Warning	FGF	Becker, Hubbard, Wadena	38 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.