Alert archive / North Dakota / Tornado Watches in 2011

Tornado Watch 613

July 8, 20114 counties in Minnesota; 8 counties in North Dakota; Marshall County, Roberts County, South Dakota

The Storm Prediction Center issued this tornado watch at Jul 8, 2011, 6:02 PM CDT for 4 counties in Minnesota; 8 counties in North Dakota; Marshall County, Roberts County, South Dakota. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued: Jul 8, 2011, 6:02 PM CDT (23:02 UTC)
Expired: Jul 9, 2011, 1:00 AM CDT
In force: 7 hr
Issued by: the Storm Prediction Center
Largest hail expected: 2 in
Strongest gust expected: 60 kt

Counties Big Stone County, MN, Clay County, MN, Traverse County, MN, Wilkin County, MN, Barnes County, ND, Cass County, ND, Eddy County, ND, Griggs County, ND, Ransom County, ND, Richland County, ND, Sargent County, ND, Steele County, ND, Marshall County, SD, Roberts County, SD

The radar

The Fargo/Grand Forks radar (KMVX), 104 km from the middle of the area, began a volume at 23:03 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: 40%
One or more EF2 to EF5 tornadoes: 20%
Ten or more severe wind reports: 30%
One or more gusts of 65 knots or more: 30%
Ten or more severe hail reports: 40%
One or more hailstones of 2 inches or more: 30%
Six or more combined severe hail and wind reports: 70%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Jul 8, 11:35 PM CDT	Severe Thunderstorm Warning	ABR	Brown, McPherson, Marshall	40 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

Bismarck Municip, ND (KBIS), launched 12:00Z, 11.0 hours before the alert went out and 200 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: 57 J/kg
Mixed-layer CIN: -207 J/kg
Mixed-layer LCL: 1101 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 95 m²/s²
0-3 km storm-relative helicity: 209 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.8

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

730 
WWUS20 KWNS 082304
SEL3
SPC WW 082304
MNZ000-NDZ000-SDZ000-090600-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 613
NWS STORM PREDICTION CENTER NORMAN OK
605 PM CDT FRI JUL 8 2011

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

       EAST-CENTRAL MINNESOTA
       SOUTHEAST NORTH DAKOTA
       NORTHEAST SOUTH DAKOTA

EFFECTIVE THIS FRIDAY NIGHT AND SATURDAY MORNING FROM 605 PM
UNTIL 100 AM CDT.

TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 60 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 40 MILES WEST OF JAMESTOWN
NORTH DAKOTA TO 55 MILES SOUTH OF DETROIT LAKES MINNESOTA.  FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU3).

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.

OTHER WATCH INFORMATION...CONTINUE...WW 610...WW 611...WW 612...

DISCUSSION...TSTMS HAVE DEVELOPED SEWD ALONG WARM FRONT FROM NW OF
JMS TO NE ABR WITHIN A NARROW CORRIDOR OF HIGHER BOUNDARY-LAYER
MOISTURE CONTENT AND MLCAPE OF 2000-2500 J/KG.  DEEP-LAYER VERTICAL
SHEAR DECREASES WITH EWD EXTENT ACROSS THE WATCH AREA WHICH MAY TEND
TO LIMIT MORE ROBUST SUPERCELL STRUCTURES.  NONETHELESS...THE
CO-LOCATION OF 200 J/KG 0-3 KM MLCAPE AND AMBIENT VORTICITY INVOF OF
SURFACE BOUNDARY WILL SUPPORT LOW-LEVEL UPDRAFT STRETCHING/ROTATION
WITH AN ATTENDANT RISK FOR A COUPLE TORNADOES.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 29020.


...MEAD

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 8, 5:38 PM CDT	Mesoscale Discussion	SPC	Becker, Big Stone, Clay, Grant, Kittson, Mahnomen and 9 more	2 hr
Jul 8, 2:13 PM CDT	Mesoscale Discussion	SPC	Adams, Billings, Bottineau, Bowman, Burke, Burleigh and 20 more	62 min
Jul 8, 2:32 PM CDT	Tornado Watch	SPC	Adams, Billings, Bottineau, Bowman, Burke, Burleigh and 30 more	9 hr
Jul 8, 4:29 PM CDT	Mesoscale Discussion	SPC	Bennett, Brown, Brule, Buffalo, Butte, Campbell and 31 more	2 hr
Jul 8, 4:48 PM CDT	Severe Thunderstorm Watch	SPC	Bennett, Butte, Campbell, Corson, Custer, Dewey and 14 more	7 hr

Nearby

Tornado Watches in North Dakota, 2011 Tornado Watches in Minnesota, 2011 Tornado Watches in South Dakota, 2011 Every tornado watch in 2011

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.