Alert archive / Nebraska / Mesoscale Discussions in 2017

Mesoscale Discussion 520

April 19, 20179 counties in Iowa; Atchison County, Holt County, Missouri; 15 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Apr 19, 2017, 5:30 PM CDT for 9 counties in Iowa; Atchison County, Holt County, Missouri; 15 counties in Nebraska. It was in force for 60 min.

The area

The outline as issued.

The facts

Issued: Apr 19, 2017, 5:30 PM CDT (22:30 UTC)
Expired: Apr 19, 2017, 6:30 PM CDT
In force: 60 min
Issued by: the Storm Prediction Center

All 26 counties

Audubon County, IA, Cass County, IA, Fremont County, IA, Harrison County, IA, Mills County, IA, Montgomery County, IA, Page County, IA, Pottawattamie County, IA, Shelby County, IA, Atchison County, MO, Holt County, MO, Cass County, NE, Dodge County, NE, Douglas County, NE, Gage County, NE, Jefferson County, NE, Johnson County, NE, Lancaster County, NE, Nemaha County, NE, Otoe County, NE, Pawnee County, NE, Richardson County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE, Washington County, NE

The radar

The Omaha radar (KOAX), 33 km from the middle of the area, began a volume at 22:28 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, 10.5 hours before the alert went out and 33 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: 1072 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 194 m²/s²
0-3 km storm-relative helicity: 314 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

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 19, 2:29 PM CDT	Mesoscale Discussion	SPC	Crawford, Fremont, Harrison, Ida, Mills, Monona and 4 more	3 hr
Apr 19, 3:23 PM CDT	Tornado Watch	SPC	Adair, Adams, Audubon, Carroll, Cass, Crawford and 11 more	7 hr
Apr 19, 6:55 PM CDT	Mesoscale Discussion	SPC	Boone, Calhoun, Carroll, Cerro Gordo, Crawford, Floyd and 15 more	95 min
Apr 19, 3:49 PM CDT	Severe Thunderstorm Watch	SPC	Fillmore, Nuckolls, Thayer	7 hr

Nearby

Mesoscale Discussions in Nebraska, 2017 Mesoscale Discussions in Iowa, 2017 Mesoscale Discussions in Missouri, 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.