Alert archive / Minnesota / Tornado Watches in 2011

Tornado Watch 651

July 17, 20119 counties in Minnesota; 7 counties in North Dakota

The Storm Prediction Center issued this tornado watch at Jul 17, 2011, 12:49 PM CDT for 9 counties in Minnesota; 7 counties in North Dakota. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: Jul 17, 2011, 12:49 PM CDT (17:49 UTC)
Expired: Jul 17, 2011, 3:41 PM CDT
In force: 3 hr
Issued by: the Storm Prediction Center
Largest hail expected: 3 in
Strongest gust expected: 70 kt

Counties Becker County, MN, Clay County, MN, Clearwater County, MN, Hubbard County, MN, Mahnomen County, MN, Norman County, MN, Pennington County, MN, Polk County, MN, Red Lake County, MN, Barnes County, ND, Cass County, ND, Grand Forks County, ND, Griggs County, ND, Nelson County, ND, Steele County, ND, Traill County, ND

The radar

The Fargo/Grand Forks radar (KMVX), 34 km from the middle of the area, began a volume at 17:50 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: 50%
One or more EF2 to EF5 tornadoes: 30%
Ten or more severe wind reports: 70%
One or more gusts of 65 knots or more: 60%
Ten or more severe hail reports: 80%
One or more hailstones of 2 inches or more: 70%
Six or more combined severe hail and wind reports: 95%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Jul 17, 2:24 PM CDT	Tornado Warning	FGF	Barnes, Griggs	36 min
Jul 17, 2:57 PM CDT	Tornado Warning	FGF	Barnes, Griggs	48 min
Jul 17, 3:34 PM CDT	Tornado Warning	FGF	Barnes, Griggs, Steele	41 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, 5.8 hours before the alert went out and 286 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: 1146 J/kg
Mixed-layer CIN: -217 J/kg
Mixed-layer LCL: 1112 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 167 m²/s²
0-3 km storm-relative helicity: 135 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.0

Open this sounding in Storm Lab

The text

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

428 
WWUS20 KWNS 171750
SEL1  
SPC WW 171750
MNZ000-NDZ000-172200-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 651
NWS STORM PREDICTION CENTER NORMAN OK
1250 PM CDT SUN JUL 17 2011

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

       NORTHWEST MINNESOTA
       EAST CENTRAL NORTH DAKOTA

EFFECTIVE THIS SUNDAY AFTERNOON FROM 1250 PM UNTIL 500 PM CDT.

TORNADOES...HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 45 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 60 MILES WEST SOUTHWEST OF
GRAND FORKS NORTH DAKOTA TO 15 MILES SOUTHEAST OF BEMIDJI
MINNESOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).

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 650...

DISCUSSION...LONG-LIVED SUPERCELL CONTINUES TO MOVE EWD/ESEWD ALONG
A WEAK SURFACE BOUNDARY INTO E CENTRAL ND.  THE LOW LEVELS HAVE
CONTINUED TO DESTABILIZE...WITH MLCAPE NOW IN EXCESS OF 5000 J/KG
WITH DIMINISHING CONVECTIVE INHIBITION.  THE INSTABILITY/DEEP-LAYER
SHEAR COMBINATION WILL CONTINUE TO SUPPORT SUPERCELLS...WHILE THE
EXTREME INSTABILITY/RICH MOISTURE AND CORRIDOR OF ENHANCED LOW-LEVEL
SHEAR NEAR THE BOUNDARY WILL SUPPORT A RISK FOR A FEW TORNADOES THIS
AFTERNOON.  ALSO...THERE WILL STILL BE THE POTENTIAL FOR THE
CONVECTION TO GROW UPSCALE INTO A BOWING MCS...WITH AN ACCOMPANYING
RISK FOR DAMAGING WINDS.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
650. MEAN STORM MOTION VECTOR 28035.


...THOMPSON

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 16, 9:25 PM CDT	Mesoscale Discussion	SPC	Becker, Beltrami, Clay, Clearwater, Kittson, Lake of the Woods and 7 more	95 min
Jul 16, 11:37 PM CDT	Mesoscale Discussion	SPC	Becker, Beltrami, Clay, Clearwater, Hubbard, Kittson and 9 more	23 min
Jul 17, 9:15 AM CDT	Mesoscale Discussion	SPC	Becker, Clay, Clearwater, Kittson, Mahnomen, Marshall and 4 more	2 hr
Jul 17, 9:58 AM CDT	Severe Thunderstorm Watch	SPC	Becker, Beltrami, Clay, Clearwater, Hubbard, Kittson and 8 more	7 hr
Jul 17, 10:24 AM CDT	Mesoscale Discussion	SPC	Becker, Clay, Clearwater, Hubbard, Mahnomen, Norman and 5 more	66 min
Jul 17, 1:42 PM CDT	Mesoscale Discussion	SPC	Aitkin, Becker, Beltrami, Benton, Cass, Clay and 18 more	93 min
Jul 17, 3:37 PM CDT	Tornado Watch	SPC	Becker, Clay, Grant, Otter Tail, Wadena, Wilkin	6 hr
Jul 17, 4:34 PM CDT	Severe Thunderstorm Watch	SPC	Aitkin, Benton, Carlton, Cass, Chippewa, Cook and 19 more	7 hr
Jul 17, 6:34 PM CDT	Mesoscale Discussion	SPC	Big Stone, Traverse	56 min
Jul 17, 11:01 AM CDT	Mesoscale Discussion	SPC	Benson, Eddy, Foster, Grand Forks, Nelson, Ramsey	89 min

Nearby

Tornado Watches in Minnesota, 2011 Tornado Watches in North 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.