Alert archive / North Dakota / Tornado Warnings in 2017

Tornado Warning 36, NWS Grand Forks, ND

July 21, 2017Benson County, North Dakota

NWS Grand Forks, ND issued this tornado warning at Jul 21, 2017, 10:49 PM CDT for Benson County, North Dakota. It was in force for 26 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 21, 2017, 10:49 PM CDT (03:49 UTC)
Expired: Jul 21, 2017, 11:15 PM CDT
In force: 26 min
Issued by: NWS Grand Forks, ND
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 1.5 in

County Benson County, ND

The radar

The Minot AFB radar (KMBX), 97 km from the middle of the area, began a volume at 03:51 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 21, 11:00 PM CDT	HAIL 1	6 S Pleasant Lake, ND
Jul 21, 11:06 PM CDT	TSTM WND GST 48	1 N Baker, ND	PEAK WINDS MEASURED AT AN NDAWN STATION.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Bismarck Municip, ND (KBIS), launched 00:00Z, 3.8 hours before the alert went out and 162 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: 2130 J/kg
Mixed-layer CIN: -32 J/kg
Mixed-layer LCL: 1710 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 59 m²/s²
0-3 km storm-relative helicity: 83 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 3.7

Open this sounding in Storm Lab

The text

As transmitted.

169 
WFUS53 KFGF 220349
TORFGF
NDC005-220430-
/O.NEW.KFGF.TO.W.0036.170722T0349Z-170722T0430Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Eastern ND/Grand Forks ND
1049 PM CDT FRI JUL 21 2017

The National Weather Service in Grand Forks has issued a

* Tornado Warning for...
  Southwestern Benson County in northeastern North Dakota...

* Until 1130 PM CDT.

* At 1048 PM CDT, a severe thunderstorm capable of producing a
  tornado was located near Silva, or 46 miles southeast of Bottineau,
  moving southeast at 25 mph.

  HAZARD...Tornado and ping pong ball size hail. 

  SOURCE...Radar indicated rotation. 

  IMPACT...Expect damage to mobile homes, roofs, and vehicles. 

* This dangerous storm will be near...
  Fillmore around 1055 PM CDT. 
  Esmond and Baker around 1105 PM CDT. 
  Maddock around 1120 PM CDT. 
  Flora around 1125 PM CDT. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4834 9985 4791 9910 4785 9933 4785 9981
      4802 9981 4802 9985
TIME...MOT...LOC 0348Z 314DEG 42KT 4826 9991 

TORNADO...RADAR INDICATED
HAIL...1.50IN

$$

VG

1 follow-up statement

406 
WWUS53 KFGF 220415
SVSFGF

Severe Weather Statement
National Weather Service Eastern ND/Grand Forks ND
1115 PM CDT FRI JUL 21 2017

NDC005-220424-
/O.CAN.KFGF.TO.W.0036.000000T0000Z-170722T0430Z/
Benson ND-
1115 PM CDT FRI JUL 21 2017

...THE TORNADO WARNING FOR SOUTHWESTERN BENSON COUNTY IS CANCELLED...
        
The storm which prompted the warning has moved out of the area.
Therefore the warning has been cancelled.

LAT...LON 4834 9985 4791 9910 4785 9933 4785 9981
      4802 9981 4802 9985
TIME...MOT...LOC 0412Z 314DEG 42KT 4804 9957 

$$

vg

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 21, 10:31 PM CDT	Special Weather Statement	FGF	Barnes	44 min
Jul 21, 11:07 PM CDT	Special Weather Statement	FGF	Ransom	38 min
Jul 21, 11:14 PM CDT	Severe Thunderstorm Warning	FGF	Benson, Ramsey	46 min
Jul 22, 12:25 AM CDT	Severe Thunderstorm Warning	FGF	Eddy	27 min
Jul 22, 12:36 AM CDT	Special Weather Statement	FGF	Nelson	24 min
Jul 22, 2:18 AM CDT	Special Weather Statement	FGF	Cass, Traill	27 min
Jul 22, 2:37 AM CDT	Severe Thunderstorm Warning	FGF	Cass, Traill	38 min
Jul 22, 3:07 AM CDT	Severe Thunderstorm Warning	FGF	Cass, Ransom, Richland, Sargent	53 min

Nearby

Tornado Warnings in North Dakota, 2017 Every tornado warning in 2017 Tornadoes in 2017

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.