Alert archive / Minnesota / Tornado Watches in 2017

Tornado Watch 306

June 7, 201713 counties in Minnesota; Cass County, Grand Forks County, Traill County, North Dakota

The Storm Prediction Center issued this tornado watch at Jun 7, 2017, 2:11 PM CDT for 13 counties in Minnesota; Cass County, Grand Forks County, Traill County, North Dakota. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued: Jun 7, 2017, 2:11 PM CDT (19:11 UTC)
Expired: Jun 7, 2017, 6:00 PM CDT
In force: 4 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1.5 in
Strongest gust expected: 60 kt

Counties Becker County, MN, Clay County, MN, Clearwater County, MN, Hubbard County, MN, Mahnomen County, MN, Marshall County, MN, Norman County, MN, Otter Tail County, MN, Pennington County, MN, Polk County, MN, Red Lake County, MN, Wadena County, MN, Wilkin County, MN, Cass County, ND, Grand Forks County, ND, Traill County, ND

The radar

The Fargo/Grand Forks radar (KMVX), 73 km from the middle of the area, began a volume at 19:15 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 SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes: 30%
One or more EF2 to EF5 tornadoes: 10%
Ten or more severe wind reports: 10%
One or more gusts of 65 knots or more: 10%
Ten or more severe hail reports: 20%
One or more hailstones of 2 inches or more: 10%
Six or more combined severe hail and wind reports: 60%

Warnings issued inside it

2 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Jun 7, 2:13 PM CDT	Tornado Warning	FGF	Norman, Polk	47 min
Jun 7, 2:39 PM CDT	Severe Thunderstorm Warning	FGF	Marshall	20 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

International Fa, MN (KINL), launched 12:00Z, 7.2 hours before the alert went out and 265 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2122 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 77 m²/s²
0-3 km storm-relative helicity: 118 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

494 
WWUS20 KWNS 071906
SEL6  
SPC WW 071906
MNZ000-NDZ000-072300-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 306
NWS Storm Prediction Center Norman OK
210 PM CDT Wed Jun 7 2017

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Northwest Minnesota
  Far eastern North Dakota

* Effective this Wednesday afternoon and evening from 210 PM
  until 600 PM CDT.

* Primary threats include...
  A couple tornadoes possible
  Isolated large hail events to 1.5 inches in diameter possible

SUMMARY...A weak upper low and surface boundary in conjunction with
adequate moisture and steep lapse rates will continue to support the
possibility of brief tornadoes as storms develop east/southeastward
into northwest Minnesota.

The tornado watch area is approximately along and 60 statute miles
north and south of a line from 35 miles northwest of Fargo ND to 30
miles south of Bemidji MN. For a complete depiction of the watch see
the associated watch outline update (WOUS64 KWNS WOU6).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.

&&

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 1.5 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 400. Mean
storm motion vector 28010.

...Guyer

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 7, 1:36 PM CDT	Mesoscale Discussion	SPC	Becker, Beltrami, Clay, Clearwater, Hubbard, Mahnomen and 5 more	2 hr
Jun 7, 5:30 PM CDT	Mesoscale Discussion	SPC	Becker, Clearwater, Hubbard, Mahnomen, Norman, Otter Tail and 4 more	60 min

Nearby

Tornado Watches in Minnesota, 2017 Tornado Watches in North Dakota, 2017 Every tornado watch 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.