Alert archive / North Dakota / Tornado Watches in 2007

Tornado Watch 303

May 28, 20079 counties in Minnesota; 13 counties in North Dakota

The Storm Prediction Center issued this tornado watch at May 28, 2007, 5:35 PM CDT for 9 counties in Minnesota; 13 counties in North Dakota. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued: May 28, 2007, 5:35 PM CDT (22:35 UTC)
Expired: May 28, 2007, 10:03 PM CDT
In force: 4 hr
Issued by: the Storm Prediction Center
Largest hail expected: 2.5 in
Strongest gust expected: 60 kt

All 22 counties

Clay County, MN, Kittson County, MN, Mahnomen County, MN, Marshall County, MN, Norman County, MN, Pennington County, MN, Polk County, MN, Red Lake County, MN, Roseau County, MN, Barnes County, ND, Benson County, ND, Cass County, ND, Cavalier County, ND, Eddy County, ND, Grand Forks County, ND, Griggs County, ND, Nelson County, ND, Pembina County, ND, Ramsey County, ND, Steele County, ND, Traill County, ND, Walsh County, ND

The radar

The Fargo/Grand Forks radar (KMVX), 59 km from the middle of the area, began a volume at 22:36 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

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

Issued	Product	Office	Counties	Lasted
May 28, 6:38 PM CDT	Severe Thunderstorm Warning	FGF	Kittson	67 min
May 28, 7:30 PM CDT	Tornado Warning	FGF	Kittson	36 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, 10.6 hours before the alert went out and 281 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: 562 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 135 m²/s²
0-3 km storm-relative helicity: 218 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.

000
WWUS20 KWNS 282232
SEL3  
SPC WW 282232
MNZ000-NDZ000-290500-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 303
NWS STORM PREDICTION CENTER NORMAN OK
530 PM CDT MON MAY 28 2007

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

       NORTHWEST MINNESOTA
       NORTHEAST INTO EAST CENTRAL NORTH DAKOTA

EFFECTIVE THIS MONDAY AFTERNOON FROM 530 PM UNTIL MIDNIGHT CDT.

TORNADOES...HAIL TO 2.5 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 80 STATUTE
MILES EAST AND WEST OF A LINE FROM 15 MILES NORTH NORTHEAST OF
HALLOCK MINNESOTA TO 40 MILES WEST SOUTHWEST OF FARGO NORTH
DAKOTA.  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 302...

DISCUSSION...CAP CONTINUES TO WEAKEN INVOF SURFACE LOW NEAR DVL
EARLY THIS EVENING...WHERE AIR MASS IS MODERATELY UNSTABLE AND
STRONGLY SHEARED.  THUNDERSTORMS ARE EXPECTED TO FORM DURING THE
NEXT HOUR OR SO NEAR THE LOW CENTER AND SURFACE FRONT EXTENDING INTO
CENTRAL ND.  STORMS SHOULD FORM AS SUPERCELLS WITH ATTENDANT
ISOLATED TORNADO THREAT AS THEY MOVE EWD BEFORE EVOLVING INTO A
CLUSTER/MCS LATER THIS EVENING.  LARGE HAIL AND DAMAGING WINDS ARE
ALSO EXPECTED.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 24025.


...EVANS

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 28, 3:17 PM CDT	Mesoscale Discussion	SPC	Polk	118 min
May 28, 7:27 AM CDT	Mesoscale Discussion	SPC	Benson, Bottineau, McHenry, McLean, Pierce, Rolette and 3 more	93 min
May 28, 4:35 PM CDT	Severe Thunderstorm Watch	SPC	Adams, Burleigh, Dickey, Emmons, Foster, Grant and 7 more	9 hr

Nearby

Tornado Watches in North Dakota, 2007 Tornado Watches in Minnesota, 2007 Every tornado watch in 2007

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.