Alert archive / Nebraska / Mesoscale Discussions in 2017

Mesoscale Discussion 499

April 15, 20174 counties in Iowa; 14 counties in Nebraska; Clay County, Union County, South Dakota

The Storm Prediction Center issued this mesoscale discussion at Apr 15, 2017, 6:22 PM CDT for 4 counties in Iowa; 14 counties in Nebraska; Clay County, Union County, South Dakota. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued: Apr 15, 2017, 6:22 PM CDT (23:22 UTC)
Expired: Apr 15, 2017, 7:45 PM CDT
In force: 83 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

Counties Cherokee County, IA, Monona County, IA, Plymouth County, IA, Woodbury County, IA, Burt County, NE, Cedar County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Madison County, NE, Pierce County, NE, Platte County, NE, Stanton County, NE, Thurston County, NE, Washington County, NE, Wayne County, NE, Clay County, SD, Union County, SD

The radar

The Omaha radar (KOAX), 96 km from the middle of the area, began a volume at 23:26 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

Omaha, NE (KOAX), launched 12:00Z, 11.4 hours before the alert went out and 96 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: 1748 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: -29 m²/s²
0-3 km storm-relative helicity: -118 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.0

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 15, 4:01 PM CDT	Mesoscale Discussion	SPC	Adair, Adams, Audubon, Boone, Buena Vista, Calhoun and 46 more	119 min
Apr 15, 5:05 PM CDT	Severe Thunderstorm Watch	SPC	Adair, Adams, Audubon, Boone, Calhoun, Carroll and 35 more	7 hr
Apr 15, 5:06 PM CDT	Mesoscale Discussion	SPC	Cedar, Clayton, Clinton, Delaware, Dubuque, Henry and 10 more	84 min
Apr 14, 8:37 PM CDT	Mesoscale Discussion	SPC	Arthur, Banner, Cheyenne, Deuel, Garden, Keith and 3 more	113 min
Apr 14, 9:17 PM CDT	Mesoscale Discussion	SPC	Adams, Boone, Buffalo, Butler, Clay, Colfax and 31 more	88 min

Nearby

Mesoscale Discussions in Nebraska, 2017 Mesoscale Discussions in Iowa, 2017 Mesoscale Discussions in South Dakota, 2017 Every mesoscale discussion in 2017

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.