Alert archive / Nebraska / Mesoscale Discussions in 2005

Mesoscale Discussion 587

April 18, 20054 states

The Storm Prediction Center issued this mesoscale discussion at Apr 18, 2005, 6:26 PM CDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Apr 18, 2005, 6:26 PM CDT (23:26 UTC)
Expired
Apr 18, 2005, 8:30 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 53 counties

Cherokee County, IA, Crawford County, IA, Fremont County, IA, Harrison County, IA, Ida County, IA, Lyon County, IA, Mills County, IA, Monona County, IA, O'Brien County, IA, Osceola County, IA, Plymouth County, IA, Pottawattamie County, IA, Shelby County, IA, Sioux County, IA, Woodbury County, IA, Atchison County, MO, Burt County, NE, Butler County, NE, Cass County, NE, Cedar County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Douglas County, NE, Fillmore County, NE, Gage County, NE, Jefferson County, NE, Johnson County, NE, Lancaster County, NE, Madison County, NE, Nemaha County, NE, Otoe County, NE, Pawnee County, NE, Pierce County, NE, Platte County, NE, Polk County, NE, Richardson County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Stanton County, NE, Thurston County, NE, Washington County, NE, Wayne County, NE, York County, NE, Clay County, SD, Lincoln County, SD, Turner County, SD, Union County, SD, Yankton County, SD

The radar

The Omaha radar (KOAX), 29 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 11.4 hours before the alert went out and 29 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 12:00Z on 2005-04-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 12:00Z on 2005-04-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -109 square meters per square second.193958Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1390 m above ground
0-6 km bulk shear
10 kt
0-1 km storm-relative helicity
-109 m²/s²
0-3 km storm-relative helicity
-95 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

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
Apr 18, 3:30 PM CDTSevere Thunderstorm WatchSPCCherokee, Crawford, Fremont, Harrison, Ida, Lyon and 9 more7 hr
Apr 18, 12:08 PM CDTMesoscale DiscussionSPCBurt, Butler, Cass, Colfax, Cuming, Dodge and 22 more2 hr
Apr 18, 5:56 PM CDTMesoscale DiscussionSPCArthur, Chase, Cheyenne, Deuel, Dundy, Garden and 5 more3 hr

Nearby

Mesoscale Discussions in Nebraska, 2005Mesoscale Discussions in Iowa, 2005Mesoscale Discussions in South Dakota, 2005Every mesoscale discussion in 2005

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.