Alert archive / North Dakota / Severe Thunderstorm Watches in 2007

Severe Thunderstorm Watch 686

September 23, 20074 counties in Minnesota; 13 counties in North Dakota

The Storm Prediction Center issued this severe thunderstorm watch at Sep 23, 2007, 7:53 PM CDT for 4 counties in Minnesota; 13 counties in North Dakota. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Sep 23, 2007, 7:53 PM CDT (00:53 UTC)
Expired
Sep 23, 2007, 11:06 PM CDT
In force
3 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt

Counties Kittson County, MN, Marshall County, MN, Polk 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), 91 km from the middle of the area, began a volume at 00:52 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
20%
One or more EF2 to EF5 tornadoes
5%
Ten or more severe wind reports
50%
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
70%

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 00:00Z, 0.9 hours before the alert went out and 252 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-pSkew-T log-p diagram, Bismarck Municip, ND at 00:00Z on 2007-09-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Bismarck Municip, ND at 00:00Z on 2007-09-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -63 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
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
2707 m above ground
0-6 km bulk shear
67 kt
0-1 km storm-relative helicity
-63 m²/s²
0-3 km storm-relative helicity
66 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 23, 9:57 PM CDTMesoscale DiscussionSPCKittson, Marshall, Pennington, Polk, Red Lake, Roseau63 min
Sep 24, 3:54 PM CDTMesoscale DiscussionSPCBlue Earth, Carver, Dakota, Dodge, Faribault, Freeborn and 14 more2 hr
Sep 24, 4:57 PM CDTSevere Thunderstorm WatchSPCAnoka, Blue Earth, Carlton, Carver, Chisago, Cook and 23 more5 hr

Nearby

Severe Thunderstorm Watches in North Dakota, 2007Severe Thunderstorm Watches in Minnesota, 2007Every severe thunderstorm 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.