Alert archive / North Dakota / Tornado Warnings in 2020

Tornado Warning 31, NWS Grand Forks, ND

August 9, 2020Cass County, North Dakota

NWS Grand Forks, ND issued this tornado warning at Aug 9, 2020, 2:25 PM CDT for Cass County, North Dakota. 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
Aug 9, 2020, 2:25 PM CDT (19:25 UTC)
Expired
Aug 9, 2020, 2:55 PM CDT
In force
30 min
Issued by
NWS Grand Forks, ND
Area
Storm-based polygon
Tornado
Radar indicated
Hail
0.75 in

County Cass County, ND

The radar

The Fargo/Grand Forks radar (KMVX), 50 km from the middle of the area, began a volume at 19:26 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Aug 9, 12:18 PM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Aberdeen, SD (KABR), launched 12:00Z, 7.4 hours before the alert went out and 255 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, Aberdeen, SD at 12:00Z on 2020-08-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Aberdeen, SD at 12:00Z on 2020-08-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -35 square meters per square second.1939Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1862 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
-35 m²/s²
0-3 km storm-relative helicity
79 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

852 
WFUS53 KFGF 091925
TORFGF
NDC017-092015-
/O.NEW.KFGF.TO.W.0031.200809T1925Z-200809T2015Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Grand Forks ND
225 PM CDT Sun Aug 9 2020

The National Weather Service in Grand Forks has issued a

* Tornado Warning for...
  Northwestern Cass County in southeastern North Dakota...

* Until 315 PM CDT.
    
* At 225 PM CDT, a severe thunderstorm capable of producing a tornado
  was located over Ayr, or 27 miles east of Valley City, moving east
  at 20 mph.

  HAZARD...Tornado.

  SOURCE...Radar indicated rotation.

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

* This dangerous storm will be near...
  Erie around 235 PM CDT.
  Arthur around 255 PM CDT.
  Amenia around 300 PM CDT.

This includes Interstate 29 between mile markers 88 and 89.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 4703 9758 4717 9753 4720 9697 4695 9707
TIME...MOT...LOC 1925Z 281DEG 19KT 4707 9747 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

DJR
2 follow-up statements
024 
WWUS53 KFGF 091937
SVSFGF

Severe Weather Statement
National Weather Service Grand Forks ND
237 PM CDT Sun Aug 9 2020

NDC017-092015-
/O.CON.KFGF.TO.W.0031.000000T0000Z-200809T2015Z/
Cass ND-
237 PM CDT Sun Aug 9 2020

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 315 PM CDT FOR
NORTHWESTERN CASS COUNTY...
    
At 237 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Erie, or 29 miles northwest of Fargo, moving east at
20 mph.

HAZARD...TORNADO.

SOURCE...Radar indicated rotation.

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

This dangerous storm will be near...
  Arthur around 255 PM CDT.
  Amenia around 300 PM CDT.

This includes Interstate 29 between mile markers 88 and 89.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 4702 9750 4715 9743 4720 9697 4695 9707
TIME...MOT...LOC 1937Z 281DEG 19KT 4706 9737 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

DJR
852 
WWUS53 KFGF 091955
SVSFGF

Severe Weather Statement
National Weather Service Grand Forks ND
255 PM CDT Sun Aug 9 2020

NDC017-092005-
/O.CAN.KFGF.TO.W.0031.000000T0000Z-200809T2015Z/
Cass ND-
255 PM CDT Sun Aug 9 2020

...THE TORNADO WARNING FOR NORTHWESTERN CASS COUNTY IS CANCELLED...
    
The tornado threat has diminished and the Tornado Warning has been
cancelled. However, large hail and damaging winds remain likely and a
Severe Thunderstorm Warning remains in effect for the area.

A Severe Thunderstorm Watch remains in effect until 700 PM CDT for
southeastern North Dakota.

LAT...LON 4702 9750 4715 9743 4720 9697 4695 9707
TIME...MOT...LOC 1954Z 281DEG 19KT 4704 9723 

$$

DJR

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 9, 4:29 AM CDTSpecial Weather StatementFGFRichland61 min
Aug 9, 5:31 AM CDTSpecial Weather StatementFGFRansom59 min
Aug 9, 6:01 AM CDTSevere Thunderstorm WarningFGFBenson, Ramsey59 min
Aug 9, 6:57 AM CDTSpecial Weather StatementFGFBenson, Ramsey48 min
Aug 9, 9:09 AM CDTSpecial Weather StatementFGFGrand Forks66 min
Aug 9, 9:51 AM CDTSpecial Weather StatementFGFWalsh54 min
Aug 9, 10:12 AM CDTSevere Thunderstorm WarningFGFGrand Forks, Nelson, Ramsey, Walsh63 min
Aug 9, 10:24 AM CDTSpecial Weather StatementFGFCavalier, Towner66 min
Aug 9, 11:05 AM CDTSpecial Weather StatementFGFWalsh55 min
Aug 9, 11:24 AM CDTSpecial Weather StatementFGFCavalier, Pembina66 min
Aug 9, 11:28 AM CDTSevere Thunderstorm WarningFGFCavalier, Pembina, Walsh62 min
Aug 9, 11:42 AM CDTTornado WarningFGFCavalier, Pembina, Walsh36 min
Aug 9, 12:21 PM CDTSevere Thunderstorm WarningFGFCavalier, Pembina, Walsh54 min
Aug 9, 12:27 PM CDTSpecial Weather StatementFGFGrand Forks, Nelson, Walsh63 min
Aug 9, 1:29 PM CDTSpecial Weather StatementFGFGrand Forks61 min
Aug 9, 1:39 PM CDTSevere Thunderstorm WarningFGFGrand Forks, Walsh66 min
Aug 9, 2:10 PM CDTSevere Thunderstorm WarningFGFGrand Forks, Traill65 min
Aug 9, 2:14 PM CDTTornado WarningFGFBarnes, Cass18 min
Aug 9, 2:36 PM CDTTornado Warning Tornado observedFGFTraill28 min
Aug 9, 2:52 PM CDTSevere Thunderstorm WarningFGFCass, Traill53 min
Aug 9, 3:12 PM CDTSevere Thunderstorm WarningFGFTraill63 min
Aug 9, 3:20 PM CDTSevere Thunderstorm WarningFGFCass22 min
Aug 9, 3:35 PM CDTTornado WarningFGFCass18 min
Aug 9, 3:38 PM CDTSevere Thunderstorm WarningFGFRansom, Sargent25 min
Aug 9, 3:53 PM CDTSevere Thunderstorm WarningFGFCass, Traill48 min
Aug 9, 3:55 PM CDTSevere Thunderstorm WarningFGFSargent28 min
Aug 9, 4:24 PM CDTSpecial Weather StatementFGFSargent36 min

Nearby

Tornado Warnings in North Dakota, 2020Every tornado warning in 2020Tornadoes in 2020

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.