Alert archive / Nebraska / Mesoscale Discussions in 2017
Mesoscale Discussion 1015
The Storm Prediction Center issued this mesoscale discussion at Jun 13, 2017, 3:46 PM CDT for 4 states. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 13, 2017, 3:46 PM CDT (20:46 UTC)
- Expired
- Jun 13, 2017, 6:15 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 80%
All 47 counties
Cherokee County, IA, Lyon County, IA, Monona County, IA, O'Brien County, IA, Plymouth County, IA, Sioux County, IA, Woodbury County, IA, Rock County, MN, Adams County, NE, Antelope County, NE, Boone County, NE, Buffalo County, NE, Burt County, NE, Butler County, NE, Cedar County, NE, Clay County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Fillmore County, NE, Greeley County, NE, Hall County, NE, Hamilton County, NE, Howard County, NE, Kearney County, NE, Knox County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Pierce County, NE, Platte County, NE, Polk County, NE, Saline County, NE, Saunders County, NE, Seward County, NE, Stanton County, NE, Thurston County, NE, Wayne County, NE, York County, NE, Clay County, SD, Lincoln County, SD, Minnehaha County, SD, Turner County, SD, Union County, SD, Yankton County, SD
The radar
The Omaha radar (KOAX), 127 km from the middle of the area, began a volume at 20:47 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, 8.8 hours before the alert went out and 127 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.
- Mixed-layer CAPE
- 490 J/kg
- Mixed-layer CIN
- -541 J/kg
- Mixed-layer LCL
- 1199 m above ground
- 0-6 km bulk shear
- 18 kt
- 0-1 km storm-relative helicity
- 238 m²/s²
- 0-3 km storm-relative helicity
- 224 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
514
ACUS11 KWNS 132047
SWOMCD
SPC MCD 132046
IAZ000-MNZ000-NEZ000-SDZ000-132315-
Mesoscale Discussion 1015
NWS Storm Prediction Center Norman OK
0346 PM CDT Tue Jun 13 2017
Areas affected...ofk
Concerning...Severe potential...Watch likely
Valid 132046Z - 132315Z
Probability of Watch Issuance...80 percent
SUMMARY...A severe threat is expected to develop late this afternoon
from southern Nebraska northeastward into far southeastern South
Dakota and northwest Iowa. An isolated tornado threat along with a
potential for large hail and wind damage will be possible as cells
initiate and increase in coverage over the next couple of hours.
Weather watch issuance will likely be needed.
DISCUSSION...The latest surface analysis shows a 999 mb low over
central Nebraska with a moist airmass in place to the east of the
low. Surface dewpoints are in the mid 60s to lower 70s F across
southern and eastern Nebraska into western Iowa. This is
contributing to a corridor of strong instability with MLCAPE values
estimated by the RAP to be in the 2000 to 4000 J/kg range across the
MCD area. In addition, a belt of strong low-level flow is analyzed
by the RAP across eastern Nebraska extending north-northeastward
into far southeastern North Dakota and northwestern Iowa. As this
feature strengthens over the next few hours, new surface-based cells
are forecast to initiate from near Norfolk south-southwestward to
near Grand Island. Forecast soundings across this area late this
afternoon show moderate deep-layer shear with some directional shear
in the low-levels. This is creating 0-6 km shear in the 30 to 40 kt
range according to the RAP which will support supercell development.
The shear along with strong instability and steep low to mid-level
lapse will be favorable for large hail and wind damage with
supercells and short line segments. Hail greater than 2 inches in
diameter along with a tornado threat may accompany the more dominant
supercells.
..Broyles/Hart.. 06/13/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FSD...OAX...GID...LBF...
LAT...LON 43829647 43649729 42329826 40829922 40199892 40259729
42399557 43199540 43829647SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 13, 5:25 PM CDT | Severe Thunderstorm Watch | SPC | Harrison, Monona | 8 hr |
| Jun 13, 2:32 PM CDT | Mesoscale Discussion | SPC | Big Stone, Clay, Grant, Otter Tail, Stevens, Traverse and 1 more | 58 min |
| Jun 13, 3:13 PM CDT | Tornado Watch | SPC | Big Stone, Traverse | 7 hr |
| Jun 13, 5:43 PM CDT | Mesoscale Discussion | SPC | Big Stone, Chippewa, Clay, Grant, Lac qui Parle, Lincoln and 6 more | 2 hr |
| Jun 13, 5:56 PM CDT | Severe Thunderstorm Watch | SPC | Becker, Beltrami, Clay, Clearwater, Grant, Hubbard and 12 more | 7 hr |
| Jun 12, 9:02 PM CDT | Mesoscale Discussion | SPC | Arthur, Box Butte, Cherry, Cheyenne, Dawes, Garden and 5 more | 58 min |
| Jun 12, 11:14 PM CDT | Mesoscale Discussion | SPC | Box Butte, Cherry, Dawes, Grant, Hooker, Sheridan and 1 more | 91 min |
| Jun 12, 11:28 PM CDT | Severe Thunderstorm Watch | SPC | Beadle, Brown, Brule, Buffalo, Clark, Day and 16 more | 6 hr |
| Jun 13, 2:33 AM CDT | Mesoscale Discussion | SPC | Beadle, Brown, Campbell, Clark, Codington, Day and 11 more | 57 min |
Nearby
Mesoscale Discussions in Nebraska, 2017Mesoscale Discussions in Iowa, 2017Mesoscale Discussions in South Dakota, 2017Every 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.