Alert archive / Minnesota / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 55, NWS Grand Forks, ND

July 19, 2021Marshall County, Polk County, Minnesota

NWS Grand Forks, ND issued this severe thunderstorm warning at Jul 19, 2021, 8:58 PM CDT for Marshall County, Polk County, Minnesota. It was in force for 32 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: Jul 19, 2021, 8:58 PM CDT (01:58 UTC)
Expired: Jul 19, 2021, 9:30 PM CDT
In force: 32 min
Issued by: NWS Grand Forks, ND
Area: Storm-based polygon
Hail: 1.5 in
Wind: 50.0 mph

Counties Marshall County, MN, Polk County, MN

The radar

The Fargo/Grand Forks radar (KMVX), 71 km from the middle of the area, began a volume at 02:01 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
Jul 19, 8:58 PM CDT	HAIL 1.75	2 Ne Alvarado, MN	QUARTER TO GOLF BALL SIZED HAIL.
Jul 19, 8:58 PM CDT	HAIL 1.75	2 Ne Alvarado, MN	QUARTER TO GOLF BALL SIZED HAIL REPORTED BY THE PUBLIC.

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 00:00Z, 2.0 hours before the alert went out and 269 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: 873 J/kg
Mixed-layer CIN: -129 J/kg
Mixed-layer LCL: 1160 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 57 m²/s²
0-3 km storm-relative helicity: 112 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.2

Open this sounding in Storm Lab

The text

As transmitted.

084 
WUUS53 KFGF 200158
SVRFGF
MNC089-119-200230-
/O.NEW.KFGF.SV.W.0055.210720T0158Z-210720T0230Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Grand Forks ND
858 PM CDT Mon Jul 19 2021

The National Weather Service in Grand Forks has issued a

* Severe Thunderstorm Warning for...
  Southwestern Marshall County in northwestern Minnesota...
  Northwestern Polk County in northwestern Minnesota...

* Until 930 PM CDT.

* At 856 PM CDT, a severe thunderstorm was located over Alvarado, or 
  19 miles northeast of Grand Forks, moving southeast at 55 mph.

  HAZARD...Ping pong ball size hail.

  SOURCE...Radar indicated.

  IMPACT...People and animals outdoors will be injured. Expect 
           damage to roofs, siding, windows, and vehicles.

* This severe thunderstorm will be near...
  Warren around 900 PM CDT.
  Tabor around 905 PM CDT.
  Sherack and Angus around 910 PM CDT.
  Euclid and Key West around 915 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4817 9708 4828 9687 4796 9650 4783 9678
TIME...MOT...LOC 0156Z 322DEG 49KT 4817 9691 

HAIL...1.50IN
WIND...<50MPH
 
$$

Riddle

1 follow-up statement

781 
WWUS53 KFGF 200221
SVSFGF

Severe Weather Statement
National Weather Service Grand Forks ND
921 PM CDT Mon Jul 19 2021

MNC089-119-200231-
/O.EXP.KFGF.SV.W.0055.000000T0000Z-210720T0230Z/
Marshall MN-Polk MN-
921 PM CDT Mon Jul 19 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN MARSHALL AND
NORTHWESTERN POLK COUNTIES WILL EXPIRE AT 930 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.

LAT...LON 4817 9708 4828 9687 4796 9650 4783 9678
TIME...MOT...LOC 0221Z 326DEG 33KT 4808 9688 

$$

Riddle

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 20, 3:08 AM CDT	Dense Fog Advisory	FGF	Becker, Beltrami, Clearwater, Hubbard, Kittson, Lake of the Woods and 8 more	7 hr
Jul 20, 5:37 AM CDT	Special Weather Statement	FGF	Lake of the Woods, Roseau	53 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.