Alert archive / North Dakota / Tornado Watches in 2012

Tornado Watch 486

July 15, 201216 counties in North Dakota

The Storm Prediction Center issued this tornado watch at Jul 15, 2012, 5:31 PM CDT for 16 counties in North Dakota. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Jul 15, 2012, 5:31 PM CDT (22:31 UTC)
Expired: Jul 16, 2012, 12:00 AM CDT
In force: 6 hr
Issued by: the Storm Prediction Center
Largest hail expected: 2 in
Strongest gust expected: 60 kt

Counties Benson County, ND, Bottineau County, ND, Burke County, ND, Cavalier County, ND, Eddy County, ND, McHenry County, ND, McLean County, ND, Mountrail County, ND, Pierce County, ND, Ramsey County, ND, Renville County, ND, Rolette County, ND, Sheridan County, ND, Towner County, ND, Ward County, ND, Wells County, ND

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: 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

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

Issued	Product	Office	Counties	Lasted
Jul 15, 6:31 PM CDT	Severe Thunderstorm Warning	BIS	Burke	59 min
Jul 15, 7:28 PM CDT	Severe Thunderstorm Warning	BIS	Burke	62 min
Jul 15, 8:05 PM CDT	Tornado Warning	BIS	Burke, Renville	25 min
Jul 15, 8:28 PM CDT	Tornado Warning	BIS	Burke, Renville	32 min
Jul 15, 8:59 PM CDT	Tornado Warning	BIS	Renville	15 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, 10.5 hours before the alert went out and 185 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: 312 J/kg
Mixed-layer CIN: -301 J/kg
Mixed-layer LCL: 1428 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 339 m²/s²
0-3 km storm-relative helicity: 822 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

Open this sounding in Storm Lab

The text

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

524 
WWUS20 KWNS 152231
SEL6
SPC WW 152231
NDZ000-160500-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 486
NWS STORM PREDICTION CENTER NORMAN OK
530 PM CDT SUN JUL 15 2012

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

       NORTHERN NORTH DAKOTA

EFFECTIVE THIS SUNDAY AFTERNOON FROM 530 PM UNTIL MIDNIGHT 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 50 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 75 MILES WEST OF MINOT NORTH
DAKOTA TO 25 MILES EAST NORTHEAST OF DEVILS LAKE NORTH DAKOTA.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU6).

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.

DISCUSSION...VISIBLE IMAGERY SHOWS DEEPENING CONVECTION ALONG A N-S
SURFACE TROUGH ACROSS WRN ND...AS WELL AS NEAR THE SURFACE LOW IN NW
ND.  IT APPEARS THAT CONVECTIVE INHIBITION HAS WEAKENED ENOUGH TO
SUPPORT THUNDERSTORM DEVELOPMENT BY 23-00Z...WITH STORMS EXPECTED TO
MOVE GENERALLY EWD NEAR THE INTERNATIONAL BORDER.  BOUNDARY LAYER
MOISTURE AND LOW-LEVEL SHEAR ARE MAXIMIZED NEAR THE SURFACE WARM
FRONT...WHERE DEEP-LAYER SHEAR AND CAPE FAVOR SUPERCELLS.  THERE
WILL BE A RISK FOR A TORNADO OR TWO WITH DISCRETE STORMS INTERACTING
WITH THE WARM FRONT THIS EVENING...AND THE THREAT FOR LARGE
HAIL/DAMAGING WINDS WILL PERSIST INTO TONIGHT.

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
550. MEAN STORM MOTION VECTOR 26025.


...THOMPSON

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 15, 4:00 PM CDT	Mesoscale Discussion	SPC	Bottineau, Burke, McHenry, McLean, Mountrail, Pierce and 2 more	90 min

Nearby

Tornado Watches in North Dakota, 2012 Every tornado watch in 2012

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.