Alert archive / Nebraska / Mesoscale Discussions in 2012
Mesoscale Discussion 714
The Storm Prediction Center issued this mesoscale discussion at May 5, 2012, 2:09 PM CDT for 14 counties in Iowa; 28 counties in Nebraska; Union County, South Dakota. It was in force for 96 min.
The area
The outline as issued.
The facts
- Issued
- May 5, 2012, 2:09 PM CDT (19:09 UTC)
- Expired
- May 5, 2012, 3:45 PM CDT
- In force
- 96 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 95%
All 43 counties
Buena Vista County, IA, Calhoun County, IA, Carroll County, IA, Cherokee County, IA, Clay County, IA, Crawford County, IA, Harrison County, IA, Ida County, IA, Monona County, IA, Plymouth County, IA, Pocahontas County, IA, Sac County, IA, Webster County, IA, Woodbury County, IA, Antelope County, NE, Boone County, NE, Burt County, NE, Butler County, NE, Cedar County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Greeley County, NE, Hall County, NE, Hamilton County, NE, Howard County, NE, Knox County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Pierce County, NE, Platte County, NE, Polk County, NE, Sherman County, NE, Stanton County, NE, Thurston County, NE, Valley County, NE, Washington County, NE, Wayne County, NE, Wheeler County, NE, Union County, SD
The radar
The Omaha radar (KOAX), 94 km from the middle of the area, began a volume at 19:10 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, 7.2 hours before the alert went out and 94 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
- 2817 J/kg
- Mixed-layer CIN
- -106 J/kg
- Mixed-layer LCL
- 783 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 65 m²/s²
- 0-3 km storm-relative helicity
- 21 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
As transmitted, in the capitals the NWS used until 2016.
029
ACUS11 KWNS 051910
SWOMCD
SPC MCD 051909
IAZ000-NEZ000-SDZ000-052045-
MESOSCALE DISCUSSION 0714
NWS STORM PREDICTION CENTER NORMAN OK
0209 PM CDT SAT MAY 05 2012
AREAS AFFECTED...CNTRL/NERN NEB...SERN SD...NWRN IA
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 051909Z - 052045Z
PROBABILITY OF WATCH ISSUANCE...95 PERCENT
SUMMARY...TORNADO WATCH WILL BE NEEDED TO ADDRESS THE DEVELOPING
SEVERE THREAT FROM CNTRL/NERN NEB...NEWD INTO NWRN IA. THIS WATCH
WILL LIKELY BE ISSUED BY 21Z.
DISCUSSION...EARLY MORNING MCS ACTIVITY THAT SPREAD ACROSS SD INTO
MN HAS REINFORCED A BOUNDARY THAT CURRENTLY EXTENDS FROM CNTRL NEB
INTO THE NWRN CORNER OF IA. WHILE THIS BOUNDARY MAY CONTINUE TO SAG
SWD ACROSS PARTS OF NRN IA...STRONG HEATING OVER NEB WILL LIKELY
PREVENT ANY FURTHER SWD PUSH ACROSS THE CNTRL PLAINS. WARM SECTOR
CU FIELD APPEARS TO BE EXPANDING AND CHANGING CHARACTER ACROSS NERN
NEB INTO NWRN IA PER DEEPENING BOUNDARY LAYER. IN ALL LIKELIHOOD
THUNDERSTORMS WILL EVOLVE ALONG THE WIND SHIFT INITIALLY ACROSS NEB
AS LOW LEVEL LAPSE RATES ARE SOMEWHAT STEEPER ACROSS THIS REGION.
NEEDLESS TO SAY EXTREME INSTABILITY...SBCAPE IN EXCESS OF 4000
J/KG...AND DEEP LAYER SHEAR MORE THAN ADEQUATE TO SUPPORT ROTATING
UPDRAFTS...WILL PROVE CONDUCIVE FOR SUPERCELLS...POTENTIALLY
TORNADIC. VERY LARGE HAIL IS ALSO POSSIBLE WITH THIS ACTIVITY AND A
WATCH WILL BE ISSUED BY 21Z.
..DARROW.. 05/05/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...DMX...FSD...OAX...GID...LBF...
LAT...LON 41259972 42769775 43189498 42339381 41469641 40599852
41259972SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 4, 8:30 PM CDT | Mesoscale Discussion | SPC | Allamakee, Benton, Black Hawk, Bremer, Buchanan, Butler and 10 more | 60 min |
| May 4, 9:54 PM CDT | Mesoscale Discussion | SPC | Buena Vista, Cherokee, Crawford, Harrison, Ida, Monona and 5 more | 96 min |
| May 5, 6:49 AM CDT | Severe Thunderstorm Watch | SPC | Cherokee, Lyon, O'Brien, Osceola, Plymouth, Sioux | 7 hr |
| May 5, 11:38 AM CDT | Severe Thunderstorm Watch | SPC | Allamakee, Cerro Gordo, Chickasaw, Clayton, Emmet, Fayette and 8 more | 6 hr |
| May 5, 2:58 PM CDT | Mesoscale Discussion | SPC | Allamakee, Dickinson, Emmet, Howard, Kossuth, Mitchell and 3 more | 62 min |
| May 5, 3:52 PM CDT | Mesoscale Discussion | SPC | Buena Vista, Calhoun, Carroll, Cherokee, Clay, Crawford and 8 more | 83 min |
| May 5, 4:56 PM CDT | Mesoscale Discussion | SPC | Bremer, Buchanan, Clayton, Delaware, Dubuque, Fayette and 1 more | 94 min |
| May 5, 5:31 PM CDT | Tornado Watch | SPC | Plymouth, Sioux, Woodbury | 5 hr |
| May 5, 6:46 PM CDT | Severe Thunderstorm Watch | SPC | Lyon | 6 hr |
| May 4, 10:55 PM CDT | Mesoscale Discussion | SPC | Adams, Antelope, Boone, Buffalo, Burt, Butler and 34 more | 35 min |
| May 4, 11:00 PM CDT | Severe Thunderstorm Watch | SPC | Adams, Boone, Buffalo, Burt, Butler, Cass and 34 more | 3 hr |
| May 5, 6:21 PM CDT | Mesoscale Discussion | SPC | Boyd, Brown, Keya Paha, Rock, Thomas | 84 min |
| May 5, 6:44 PM CDT | Mesoscale Discussion | SPC | Banner, Cheyenne, Kimball | 61 min |
| May 5, 3:06 AM CDT | Mesoscale Discussion | SPC | Custer, Fall River, Haakon, Hughes, Hyde, Jackson and 9 more | 84 min |
| May 5, 3:19 AM CDT | Severe Thunderstorm Watch | SPC | Bennett, Buffalo, Butte, Custer, Dewey, Fall River and 17 more | 9 hr |
| May 5, 9:50 AM CDT | Mesoscale Discussion | SPC | Aurora, Beadle, Brookings, Brule, Buffalo, Davison and 13 more | 55 min |
Nearby
Mesoscale Discussions in Nebraska, 2012Mesoscale Discussions in Iowa, 2012Mesoscale Discussions in South Dakota, 2012Every mesoscale discussion in 2012
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.