Alert archive / Iowa / Mesoscale Discussions in 2015
Mesoscale Discussion 921
The Storm Prediction Center issued this mesoscale discussion at Jun 6, 2015, 11:00 PM CDT for 4 states. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 6, 2015, 11:00 PM CDT (04:00 UTC)
- Expired
- Jun 7, 2015, 1:00 AM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
All 41 counties
Buena Vista County, IA, Calhoun County, IA, Carroll County, IA, Cherokee County, IA, Clay County, IA, Crawford County, IA, Dickinson County, IA, Emmet 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, Sioux County, IA, Woodbury County, IA, Cottonwood County, MN, Jackson County, MN, Murray County, MN, Nobles County, MN, Pipestone County, MN, Rock County, MN, Burt County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Madison County, NE, Platte County, NE, Stanton County, NE, Thurston County, NE, Washington County, NE, Wayne County, NE, Clay County, SD, Lincoln County, SD, Union County, SD
The radar
The Sioux Falls radar (KFSD), 107 km from the middle of the area, began a volume at 04:00 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 00:00Z, 4.0 hours before the alert went out and 161 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
- 1554 J/kg
- Mixed-layer CIN
- -63 J/kg
- Mixed-layer LCL
- 1214 m above ground
- 0-6 km bulk shear
- 25 kt
- 0-1 km storm-relative helicity
- 184 m²/s²
- 0-3 km storm-relative helicity
- 388 m²/s²
- Significant tornado parameter
- 0.9
- Supercell composite
- 13.1
The text
As transmitted, in the capitals the NWS used until 2016.
435
ACUS11 KWNS 070400
SWOMCD
SPC MCD 070400
IAZ000-MNZ000-NEZ000-SDZ000-070600-
MESOSCALE DISCUSSION 0921
NWS STORM PREDICTION CENTER NORMAN OK
1100 PM CDT SAT JUN 06 2015
AREAS AFFECTED...PORTIONS OF SWRN MN...SERN SD...NERN NEB...NWRN IA
CONCERNING...TORNADO WATCH 265...
VALID 070400Z - 070600Z
THE SEVERE WEATHER THREAT FOR TORNADO WATCH 265 CONTINUES.
SUMMARY...THE SEVERE WEATHER THREAT WILL BE GREATEST OVER THE
SOUTHERN HALF OF THE WATCH AREA...WHERE DAMAGING WINDS...LARGE HAIL
AND A COUPLE TORNADOES REMAIN POSSIBLE. THE SEVERE RISK HAS LESSENED
OVER NORTHERN PORTIONS OF THE WATCH AREA. A NEW WATCH IS LIKELY
ACROSS PORTIONS OF WESTERN/CENTRAL IOWA BY 05Z.
DISCUSSION...TSTMS HAVE TRANSITIONED INTO A PRONOUNCED LINEAR
STRUCTURE WITH A WELL DEVELOPED COLD POOL ACROSS NERN NEB/NWRN IA
LATE THIS EVENING...AND LATEST RADAR DATA SUGGESTS A RISK OF
DAMAGING WINDS AND POSSIBLY A TORNADO WITH BRIEF LEADING-EDGE
CIRCULATIONS. AS THE LINE OF TSTMS CONTINUES TO MOVE EAST...THE
DOWNSTREAM ENVIRONMENT WILL REMAIN FAVORABLE FOR A CONTINUED SVR
RISK GIVEN MUCAPE OF 1000 TO 2000 J/KG AND A 40-50 KT LOW-LEVEL JET.
THE PRIMARY RISK IS FOR DAMAGING WINDS AND PERHAPS A BRIEF LOW-LEVEL
CIRCULATION. WITH TIME THE THREAT WILL INCREASE TO THE E OF WW...AND
THUS A NEW WATCH IS LIKELY PRIOR TO 05Z INTO PORTIONS OF CENTRAL IA.
ACROSS ROUGHLY THE NRN HALF OF THE WW AREA...WIDESPREAD
PRECIPITATION/COOLING HAS SUBSTANTIALLY STABILIZED THE ENVIRONMENT.
LOCALLY HEAVY RAINFALL/FLASH FLOODING REMAINS A THREAT THERE AND
FARTHER SOUTH ACROSS NERN NEB/NWRN IA...REFERENCE WPC MESOSCALE
PRECIPITATION DISCUSSION 180 FOR DETAILS.
..BUNTING.. 06/07/2015
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...MPX...DMX...FSD...OAX...
LAT...LON 41479684 41559777 41889785 42519726 43739656 44189638
44359590 44369549 43969491 42939446 42539427 42049472
41589565 41479684SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 6, 8:11 PM CDT | Mesoscale Discussion | SPC | Cherokee, Ida, Lyon, Monona, O'Brien, Osceola and 3 more | 64 min |
| Jun 6, 8:45 PM CDT | Tornado Watch | SPC | Buena Vista, Cherokee, Clay, Dickinson, Ida, Lyon and 6 more | 4 hr |
| Jun 6, 11:23 PM CDT | Severe Thunderstorm Watch | SPC | Adair, Audubon, Black Hawk, Boone, Bremer, Butler and 32 more | 6 hr |
| Jun 7, 1:56 AM CDT | Mesoscale Discussion | SPC | Adair, Adams, Benton, Black Hawk, Bremer, Buchanan and 29 more | 2 hr |
| Jun 7, 1:52 PM CDT | Mesoscale Discussion | SPC | Appanoose, Davis, Des Moines, Henry, Jefferson, Keokuk and 9 more | 53 min |
| Jun 7, 3:33 PM CDT | Severe Thunderstorm Watch | SPC | Appanoose, Clarke, Davis, Decatur, Des Moines, Henry and 10 more | 4 hr |
| Jun 7, 6:21 PM CDT | Mesoscale Discussion | SPC | Davis, Des Moines, Henry, Jefferson, Lee, Van Buren | 84 min |
| Jun 6, 7:44 PM CDT | Mesoscale Discussion | SPC | Becker, Big Stone, Chippewa, Clay, Douglas, Grant and 11 more | 91 min |
| Jun 6, 10:24 PM CDT | Mesoscale Discussion | SPC | Chippewa, Kandiyohi, Lac qui Parle, Meeker, Morrison, Pope and 3 more | 66 min |
| Jun 6, 7:55 PM CDT | Mesoscale Discussion | SPC | Chase, Dundy, Frontier, Hayes, Hitchcock, Perkins and 1 more | 95 min |
| Jun 6, 10:33 PM CDT | Mesoscale Discussion | SPC | Chase, Dawson, Dundy, Frontier, Furnas, Gosper and 5 more | 57 min |
| Jun 7, 2:36 PM CDT | Mesoscale Discussion | SPC | Chase, Dundy, Hayes, Hitchcock, Perkins | 114 min |
| Jun 7, 5:31 PM CDT | Mesoscale Discussion | SPC | Richardson | 89 min |
Nearby
Mesoscale Discussions in Iowa, 2015Mesoscale Discussions in Nebraska, 2015Mesoscale Discussions in Minnesota, 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.