Alert archive / Nebraska / Mesoscale Discussions in 2017

Mesoscale Discussion 1499

August 15, 201721 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Aug 15, 2017, 12:33 PM CDT for 21 counties in Nebraska. It was in force for 87 min.

The area

The outline as issued.

The facts

Issued: Aug 15, 2017, 12:33 PM CDT (17:33 UTC)
Expired: Aug 15, 2017, 2:00 PM CDT
In force: 87 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 21 counties

Antelope County, NE, Blaine County, NE, Boyd County, NE, Burt County, NE, Cedar County, NE, Cuming County, NE, Custer County, NE, Dakota County, NE, Dixon County, NE, Garfield County, NE, Holt County, NE, Knox County, NE, Logan County, NE, Loup County, NE, Pierce County, NE, Rock County, NE, Stanton County, NE, Thurston County, NE, Valley County, NE, Wayne County, NE, Wheeler County, NE

The radar

The Omaha radar (KOAX), 178 km from the middle of the area, began a volume at 17:37 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, 5.6 hours before the alert went out and 178 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: 609 J/kg
Mixed-layer CIN: -170 J/kg
Mixed-layer LCL: 814 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 153 m²/s²
0-3 km storm-relative helicity: 205 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
Aug 15, 3:52 PM CDT	Mesoscale Discussion	SPC	Arthur, Banner, Box Butte, Chase, Cherry, Cheyenne and 11 more	113 min
Aug 15, 5:03 PM CDT	Severe Thunderstorm Watch	SPC	Arthur, Banner, Blaine, Box Butte, Buffalo, Chase and 29 more	7 hr

Nearby

Mesoscale Discussions in Nebraska, 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.