Alert archive / Nebraska / Mesoscale Discussions in 2015

Mesoscale Discussion 1455

July 17, 20154 states

The Storm Prediction Center issued this mesoscale discussion at Jul 17, 2015, 8:57 PM CDT for 4 states. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Jul 17, 2015, 8:57 PM CDT (01:57 UTC)
Expired
Jul 17, 2015, 11:30 PM CDT
In force
3 hr
Issued by
the Storm Prediction Center
Chance of a watch
95%
All 65 counties

Audubon County, IA, Buena Vista County, IA, Calhoun County, IA, Carroll County, IA, Cherokee County, IA, Clay County, IA, Crawford County, IA, Dickinson County, IA, Harrison County, IA, Ida County, IA, Lyon County, IA, Monona County, IA, O'Brien County, IA, Osceola County, IA, Palo Alto County, IA, Plymouth County, IA, Pocahontas County, IA, Sac County, IA, Shelby County, IA, Sioux County, IA, Woodbury County, IA, Nobles County, MN, Antelope County, NE, Boone County, NE, Boyd County, NE, Burt County, NE, Butler County, NE, Cedar County, NE, Colfax County, NE, Cuming County, NE, Custer County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Douglas County, NE, Garfield County, NE, Greeley County, NE, Hall County, NE, Hamilton County, NE, Holt County, NE, Howard County, NE, Knox County, NE, Loup County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Pierce County, NE, Platte County, NE, Polk County, NE, Rock County, NE, Saunders County, NE, Sherman County, NE, Stanton County, NE, Thurston County, NE, Valley County, NE, Washington County, NE, Wayne County, NE, Wheeler County, NE, York County, NE, Bon Homme County, SD, Clay County, SD, Lincoln County, SD, Turner County, SD, Union County, SD, Yankton County, SD

The radar

The Omaha radar (KOAX), 122 km from the middle of the area, began a volume at 02:01 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 00:00Z, 2.0 hours before the alert went out and 122 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, Omaha, NE at 00:00Z on 2015-07-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3350 joules per kilogram.LCLLFCEL10008507005003002001001 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, Omaha, NE at 00:00Z on 2015-07-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 76 square meters per square second.19395878Sfc1 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
3350 J/kg
Mixed-layer CIN
-84 J/kg
Mixed-layer LCL
1845 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
76 m²/s²
0-3 km storm-relative helicity
131 m²/s²
Significant tornado parameter
0.1
Supercell composite
9.7

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.

IssuedProductOfficeCountiesLasted
Jul 17, 8:55 PM CDTSevere Thunderstorm WatchSPCBuena Vista, Cherokee, Clay, Dickinson, Ida, Lyon and 5 more5 hr
Jul 17, 11:26 PM CDTMesoscale DiscussionSPCBuena Vista, Cherokee, Clay, Dickinson, Emmet, Ida and 12 more2 hr
Jul 18, 2:05 AM CDTMesoscale DiscussionSPCHoward, Mitchell, Winneshiek, Worth85 min
Jul 18, 3:06 AM CDTMesoscale DiscussionSPCAllamakee, Winneshiek84 min
Jul 18, 12:31 PM CDTMesoscale DiscussionSPCAllamakee, Benton, Black Hawk, Buchanan, Cedar, Clayton and 21 more119 min
Jul 18, 1:31 PM CDTTornado WatchSPCClinton, Dubuque, Jackson, Scott5 hr
Jul 17, 7:18 PM CDTMesoscale DiscussionSPCBenton, Brown, Carver, Chippewa, Cottonwood, Douglas and 29 more117 min
Jul 17, 8:39 PM CDTSevere Thunderstorm WatchSPCAnoka, Blue Earth, Brown, Carver, Chippewa, Dakota and 27 more5 hr
Jul 17, 9:55 PM CDTMesoscale DiscussionSPCBig Stone, Grant, Traverse65 min
Jul 18, 12:23 AM CDTMesoscale DiscussionSPCAnoka, Dakota, Dodge, Goodhue, Hennepin, Houston and 7 more67 min
Jul 18, 12:41 AM CDTSevere Thunderstorm WatchSPCDodge, Fillmore, Houston, Mower, Olmsted, Wabasha and 1 more5 hr
Jul 18, 4:29 PM CDTMesoscale DiscussionSPCArthur, Banner, Chase, Cheyenne, Deuel, Garden and 5 more2 hr

Nearby

Mesoscale Discussions in Nebraska, 2015Mesoscale Discussions in Iowa, 2015Mesoscale Discussions in South Dakota, 2015Every mesoscale discussion in 2015

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.