Alert archive / Nebraska / Mesoscale Discussions in 2007

Mesoscale Discussion 1837

August 21, 2007Prowers County, Colorado; 9 counties in Kansas; 11 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Aug 21, 2007, 4:53 PM MDT for Prowers County, Colorado; 9 counties in Kansas; 11 counties in Nebraska. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued: Aug 21, 2007, 4:53 PM MDT (22:53 UTC)
Expired: Aug 21, 2007, 6:30 PM MDT
In force: 97 min
Issued by: the Storm Prediction Center

All 21 counties

Prowers County, CO, Decatur County, KS, Greeley County, KS, Logan County, KS, Norton County, KS, Rawlins County, KS, Sheridan County, KS, Sherman County, KS, Thomas County, KS, Wallace County, KS, Buffalo County, NE, Dawson County, NE, Frontier County, NE, Furnas County, NE, Gosper County, NE, Harlan County, NE, Hitchcock County, NE, Kearney County, NE, Phelps County, NE, Red Willow County, NE, Sherman County, NE

The radar

The Goodland radar (KGLD), 67 km from the middle of the area, began a volume at 22:53 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.

The nearest sounding before it

N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 10.9 hours before the alert went out and 174 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: 2298 J/kg
Mixed-layer CIN: -210 J/kg
Mixed-layer LCL: 1059 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 82 m²/s²
0-3 km storm-relative helicity: 168 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -1.6

Open this sounding in Storm Lab

The text

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

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 21, 2:50 PM MDT	Severe Thunderstorm Watch	SPC	Cheyenne, Kit Carson	6 hr
Aug 20, 7:01 PM MDT	Mesoscale Discussion	SPC	Barber, Clark, Comanche, Edwards, Finney, Ford and 15 more	89 min
Aug 20, 8:13 PM MDT	Mesoscale Discussion	SPC	Barber, Barton, Butler, Chase, Clark, Coffey and 40 more	32 min
Aug 20, 8:45 PM MDT	Severe Thunderstorm Watch	SPC	Barber, Barton, Butler, Chase, Clark, Comanche and 25 more	3 hr
Aug 20, 10:11 PM MDT	Mesoscale Discussion	SPC	Barber, Harper, Kingman	64 min
Aug 21, 1:47 PM MDT	Mesoscale Discussion	SPC	Cheyenne, Decatur, Rawlins, Sherman	118 min
Aug 20, 6:03 PM MDT	Mesoscale Discussion	SPC	Cedar	117 min
Aug 20, 6:35 PM MDT	Mesoscale Discussion	SPC	Burt, Butler, Cass, Clay, Colfax, Cuming and 27 more	85 min
Aug 21, 2:45 PM MDT	Tornado Watch	SPC	Antelope, Boone, Boyd, Cedar, Colfax, Cuming and 14 more	6 hr
Aug 21, 5:17 PM MDT	Mesoscale Discussion	SPC	Antelope, Boone, Burt, Cedar, Colfax, Cuming and 11 more	88 min
Aug 21, 5:47 PM MDT	Tornado Watch	SPC	Burt, Dodge, Washington	7 hr

Nearby

Mesoscale Discussions in Nebraska, 2007 Mesoscale Discussions in Kansas, 2007 Mesoscale Discussions in Colorado, 2007 Every mesoscale discussion 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.