Alert archive / Iowa / Mesoscale Discussions in 2017
Mesoscale Discussion 741
The Storm Prediction Center issued this mesoscale discussion at May 16, 2017, 7:31 PM CDT for 5 states. It was in force for 59 min.
The area
The outline as issued.
The facts
- Issued
- May 16, 2017, 7:31 PM CDT (00:31 UTC)
- Expired
- May 16, 2017, 8:30 PM CDT
- In force
- 59 min
- Issued by
- the Storm Prediction Center
All 144 counties
Adair County, IA, Adams County, IA, Audubon County, IA, Benton County, IA, Black Hawk County, IA, Boone County, IA, Bremer County, IA, Buena Vista County, IA, Butler County, IA, Calhoun County, IA, Carroll County, IA, Cass County, IA, Cerro Gordo County, IA, Cherokee County, IA, Chickasaw County, IA, Clarke County, IA, Clay County, IA, Crawford County, IA, Dallas County, IA, Dickinson County, IA, Emmet County, IA, Floyd County, IA, Franklin County, IA, Fremont County, IA, Greene County, IA, Grundy County, IA, Guthrie County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Harrison County, IA, Humboldt County, IA, Ida County, IA, Jasper County, IA, Kossuth County, IA, Madison County, IA, Marion County, IA, Marshall County, IA, Mills County, IA, Mitchell County, IA, Monona County, IA, Montgomery County, IA, O'Brien County, IA, Osceola County, IA, Page County, IA, Palo Alto County, IA, Plymouth County, IA, Pocahontas County, IA, Polk County, IA, Pottawattamie County, IA, Poweshiek County, IA, Ringgold County, IA, Sac County, IA, Shelby County, IA, Sioux County, IA, Story County, IA, Tama County, IA, Taylor County, IA, Union County, IA, Warren County, IA, Webster County, IA, Winnebago County, IA, Woodbury County, IA, Worth County, IA, Wright County, IA, Brown County, KS, Clay County, KS, Cloud County, KS, Dickinson County, KS, Ellis County, KS, Ellsworth County, KS, Geary County, KS, Gove County, KS, Graham County, KS, Jackson County, KS, Jewell County, KS, Lincoln County, KS, Marshall County, KS, McPherson County, KS, Mitchell County, KS, Nemaha County, KS, Norton County, KS, Osborne County, KS, Ottawa County, KS, Phillips County, KS, Pottawatomie County, KS, Republic County, KS, Riley County, KS, Rooks County, KS, Russell County, KS, Saline County, KS, Sheridan County, KS, Smith County, KS, Trego County, KS, Washington County, KS, Atchison County, MO, Holt County, MO, Nodaway County, MO, Adams County, NE, Burt County, NE, Butler County, NE, Cass County, NE, Clay County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Douglas County, NE, Fillmore County, NE, Franklin County, NE, Furnas County, NE, Gage County, NE, Hall County, NE, Hamilton County, NE, Harlan County, NE, Howard County, NE, Jefferson County, NE, Johnson County, NE, Kearney County, NE, Lancaster County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Nemaha County, NE, Nuckolls County, NE, Otoe County, NE, Pawnee County, NE, Phelps 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, Thayer County, NE, Thurston County, NE, Washington County, NE, Wayne County, NE, Webster County, NE, York County, NE, Union County, SD
The radar
The Omaha radar (KOAX), 67 km from the middle of the area, began a volume at 00:34 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
Topeka, KS (KFOE), launched 00:00Z, 0.5 hours before the alert went out and 203 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
- 388 J/kg
- Mixed-layer CIN
- -468 J/kg
- Mixed-layer LCL
- 1371 m above ground
- 0-6 km bulk shear
- 32 kt
- 0-1 km storm-relative helicity
- 66 m²/s²
- 0-3 km storm-relative helicity
- 163 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.2
The text
As transmitted.
246
ACUS11 KWNS 170032
SWOMCD
SPC MCD 170031
IAZ000-MNZ000-MOZ000-KSZ000-NEZ000-SDZ000-170130-
Mesoscale Discussion 0741
NWS Storm Prediction Center Norman OK
0731 PM CDT Tue May 16 2017
Areas affected...Much of Iowa...southern/eastern Nebraska...and
northern Kansas
Concerning...Severe Thunderstorm Watch 224...
Valid 170031Z - 170130Z
The severe weather threat for Severe Thunderstorm Watch 224
continues.
SUMMARY...The severe threat continues across WW 224. A new WW
downstream of 224 in portions of Iowa may be needed over the next
couple of hours.
DISCUSSION...Scattered, primarily hail and wind producing
thunderstorms continue across many areas in WW 224 at this time.
Over the past hour, a bow echo has organized over eastern Nebraska
that produced significant severe wind gusts near the Omaha area.
That bow echo has organized further and accelerated into western
Iowa into an airmass sufficiently unstable to sustain a severe wind
and hail threat. Convective trends in this region suggest that a
new, downstream severe thunderstorm watch may be needed in portions
of Iowa after about 01Z.
Farther southwest, multiple linear segments have evolved across
southern Nebraska and north-central Kansas. These storms will
continue to propagate north/northeastward in a pre-convective
airmass characterized by moderate instability and 40-50 knots of
deep shear, suggesting that a hail and severe wind threat will
continue for several more hours. More isolated, cellular convection
that can organize ahead of or separate from linear clusters may
exhibit an isolated tornado threat, although most recent trends
suggest that hail/wind will be the dominant severe threat.
..Cook/Guyer.. 05/17/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...DVN...ARX...MPX...DMX...EAX...FSD...OAX...TOP...
ICT...GID...DDC...GLD...
LAT...LON 42869670 43349584 43639462 43669348 43479242 42999199
42709186 42089203 41399263 40889387 40489467 39709527
38999647 38359720 38259768 38319808 38669865 38799931
38799996 38790053 38980080 39400078 40060015 40549940
42869670SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 16, 8:46 PM CDT | Severe Thunderstorm Watch | SPC | Allamakee, Black Hawk, Boone, Bremer, Butler, Cerro Gordo and 29 more | 5 hr |
| May 16, 9:43 PM CDT | Mesoscale Discussion | SPC | Adair, Adams, Audubon, Calhoun, Carroll, Cass and 16 more | 62 min |
| May 16, 11:48 PM CDT | Mesoscale Discussion | SPC | Adair, Allamakee, Black Hawk, Boone, Bremer, Butler and 28 more | 117 min |
| May 17, 11:39 AM CDT | Mesoscale Discussion | SPC | Adair, Adams, Appanoose, Audubon, Boone, Carroll and 28 more | 66 min |
| May 17, 12:08 PM CDT | Tornado Watch | SPC | Adair, Adams, Appanoose, Audubon, Black Hawk, Boone and 64 more | 7 hr |
| May 17, 12:23 PM CDT | Mesoscale Discussion | SPC | Allamakee, Clayton | 97 min |
| May 17, 2:25 PM CDT | Mesoscale Discussion | SPC | Adair, Adams, Audubon, Boone, Calhoun, Carroll and 32 more | 65 min |
| May 17, 2:38 PM CDT | Mesoscale Discussion | SPC | Allamakee, Benton, Black Hawk, Bremer, Buchanan, Butler and 15 more | 97 min |
| May 17, 3:13 PM CDT | Tornado Watch | SPC | Allamakee, Chickasaw, Clayton, Fayette, Floyd, Howard and 2 more | 9 hr |
| May 17, 3:24 PM CDT | Mesoscale Discussion | SPC | Benton, Buchanan, Cedar, Clinton, Davis, Delaware and 17 more | 66 min |
| May 17, 3:44 PM CDT | Tornado Watch | SPC | Benton, Buchanan, Cedar, Clinton, Delaware, Des Moines and 15 more | 9 hr |
| May 17, 6:05 PM CDT | Mesoscale Discussion | SPC | Allamakee, Benton, Black Hawk, Bremer, Buchanan, Cedar and 18 more | 55 min |
| May 16, 7:03 PM CDT | Severe Thunderstorm Watch | SPC | Cheyenne, Decatur, Rawlins | 5 hr |
| May 16, 9:53 PM CDT | Mesoscale Discussion | SPC | Cowley, Harper, Sumner | 37 min |
| May 16, 10:07 PM CDT | Severe Thunderstorm Watch | SPC | Barber, Cowley, Harper, Sumner | 6 hr |
| May 16, 10:45 PM CDT | Severe Thunderstorm Watch | SPC | Barton, Butler, Chase, Comanche, Dickinson, Edwards and 17 more | 5 hr |
| May 17, 1:49 AM CDT | Mesoscale Discussion | SPC | Butler, Chase, Chautauqua, Cowley, Elk, Geary and 4 more | 56 min |
Nearby
Mesoscale Discussions in Iowa, 2017Mesoscale Discussions in Nebraska, 2017Mesoscale Discussions in Kansas, 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.