Alert archive / Minnesota / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 123, NWS Grand Forks, ND

October 8, 2021Mahnomen County, Norman County, Polk County, Minnesota

NWS Grand Forks, ND issued this severe thunderstorm warning at Oct 8, 2021, 8:45 PM CDT for Mahnomen County, Norman County, Polk County, Minnesota. It was in force for 30 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
Oct 8, 2021, 8:45 PM CDT (01:45 UTC)
Expired
Oct 8, 2021, 9:15 PM CDT
In force
30 min
Issued by
NWS Grand Forks, ND
Area
Storm-based polygon
Hail
1.25 in
Wind
60.0 mph

Counties Mahnomen County, MN, Norman County, MN, Polk County, MN

The radar

The Fargo/Grand Forks radar (KMVX), 107 km from the middle of the area, began a volume at 01:46 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, 1.8 hours before the alert went out and 235 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-pSkew-T log-p diagram, International Fa, MN at 00:00Z on 2021-10-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 61 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, International Fa, MN at 00:00Z on 2021-10-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 20 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
61 J/kg
Mixed-layer CIN
-29 J/kg
Mixed-layer LCL
1063 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
20 m²/s²
0-3 km storm-relative helicity
35 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

459 
WUUS53 KFGF 090145
SVRFGF
MNC087-107-119-090245-
/O.NEW.KFGF.SV.W.0123.211009T0145Z-211009T0245Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Grand Forks ND
845 PM CDT Fri Oct 8 2021

The National Weather Service in Grand Forks has issued a

* Severe Thunderstorm Warning for...
  East central Norman County in northwestern Minnesota...
  Southeastern Polk County in northwestern Minnesota...
  Northern Mahnomen County in northwestern Minnesota...

* Until 945 PM CDT.

* At 844 PM CDT, a severe thunderstorm was located over northwestern
  White Earth Nation, or 39 miles north of Detroit Lakes, moving east
  at 25 mph.

  HAZARD...60 mph wind gusts and half dollar size hail.

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees.

* Locations impacted include...
  Beaulieu, Island Lake in Mahnomen County, Mahkonce and Lengby.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4732 9611 4746 9613 4754 9564 4729 9559
TIME...MOT...LOC 0144Z 263DEG 20KT 4738 9600 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.25 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Perroux
2 follow-up statements
948 
WWUS53 KFGF 090159
SVSFGF

Severe Weather Statement
National Weather Service Grand Forks ND
859 PM CDT Fri Oct 8 2021

MNC107-090209-
/O.CAN.KFGF.SV.W.0123.000000T0000Z-211009T0245Z/
Norman MN-
859 PM CDT Fri Oct 8 2021

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL NORMAN COUNTY IS
CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 4731 9601 4747 9602 4754 9564 4729 9559
TIME...MOT...LOC 0159Z 263DEG 20KT 4739 9588 

$$

MNC087-119-090245-
/O.CON.KFGF.SV.W.0123.000000T0000Z-211009T0245Z/
Polk MN-Mahnomen MN-
859 PM CDT Fri Oct 8 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 945 PM CDT
FOR SOUTHEASTERN POLK AND NORTHERN MAHNOMEN COUNTIES...

At 859 PM CDT, a severe thunderstorm was located over northwestern
White Earth Nation, or 39 miles north of Detroit Lakes, moving east
at 25 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees.

Locations impacted include...
Mahnomen, Island Lake in Mahnomen County, Bejou, Beaulieu, Mahkonce,
Lengby and northern White Earth Nation.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4731 9601 4747 9602 4754 9564 4729 9559
TIME...MOT...LOC 0159Z 263DEG 20KT 4739 9588 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Perroux
894 
WWUS53 KFGF 090215
SVSFGF

Severe Weather Statement
National Weather Service Grand Forks ND
915 PM CDT Fri Oct 8 2021

MNC087-119-090224-
/O.CAN.KFGF.SV.W.0123.000000T0000Z-211009T0245Z/
Polk MN-Mahnomen MN-
915 PM CDT Fri Oct 8 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN POLK AND NORTHERN
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
gusty winds are still possible with this thunderstorm.

LAT...LON 4731 9601 4747 9602 4754 9564 4729 9559
TIME...MOT...LOC 0213Z 263DEG 20KT 4740 9575 

$$

Perroux

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 8, 7:07 PM CDTSpecial Weather StatementFGFNorman23 min
Oct 8, 7:13 PM CDTSpecial Weather StatementFGFRed Lake32 min
Oct 8, 7:26 PM CDTSpecial Weather StatementFGFNorman34 min
Oct 8, 7:51 PM CDTSpecial Weather StatementFGFNorman24 min
Oct 8, 8:12 PM CDTSpecial Weather StatementFGFMahnomen33 min
Oct 8, 8:41 PM CDTSpecial Weather StatementFGFMahnomen34 min
Oct 8, 8:58 PM CDTSpecial Weather StatementFGFMahnomen32 min
Oct 8, 9:13 PM CDTSpecial Weather StatementFGFMahnomen32 min
Oct 8, 9:38 PM CDTSpecial Weather StatementFGFClearwater37 min
Oct 8, 10:02 PM CDTSpecial Weather StatementFGFClearwater28 min
Oct 9, 6:43 PM CDTSevere Thunderstorm WarningFGFWilkin62 min

Nearby

Severe Thunderstorm Warnings in Minnesota, 2021Every 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.