Alert archive / Nebraska / Mesoscale Discussions in 2012
Mesoscale Discussion 669
The Storm Prediction Center issued this mesoscale discussion at May 2, 2012, 10:43 PM CDT for 5 counties in Iowa; 38 counties in Nebraska; Clay County, Union County, South Dakota. It was in force for 62 min.
The area
The outline as issued.
The facts
- Issued
- May 2, 2012, 10:43 PM CDT (03:43 UTC)
- Expired
- May 2, 2012, 11:45 PM CDT
- In force
- 62 min
- Issued by
- the Storm Prediction Center
All 45 counties
Harrison County, IA, Monona County, IA, Plymouth County, IA, Sioux County, IA, Woodbury County, IA, Adams County, NE, Boone 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, Douglas County, NE, Fillmore County, NE, Franklin County, NE, Hall County, NE, Hamilton County, NE, Howard County, NE, Jefferson County, NE, Kearney County, NE, Lancaster County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Nuckolls County, NE, Pierce County, NE, Platte County, NE, Polk 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, Clay County, SD, Union County, SD
The radar
The Omaha radar (KOAX), 66 km from the middle of the area, began a volume at 03:46 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, 3.7 hours before the alert went out and 66 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
- 2533 J/kg
- Mixed-layer CIN
- -7 J/kg
- Mixed-layer LCL
- 1223 m above ground
- 0-6 km bulk shear
- 37 kt
- 0-1 km storm-relative helicity
- 46 m²/s²
- 0-3 km storm-relative helicity
- 102 m²/s²
- Significant tornado parameter
- 0.2
- Supercell composite
- 1.4
The text
As transmitted, in the capitals the NWS used until 2016.
709
ACUS11 KWNS 030343
SWOMCD
SPC MCD 030343
IAZ000-NEZ000-SDZ000-030445-
MESOSCALE DISCUSSION 0669
NWS STORM PREDICTION CENTER NORMAN OK
1043 PM CDT WED MAY 02 2012
AREAS AFFECTED...SRN TO ERN NEB
CONCERNING...SEVERE THUNDERSTORM WATCH 226...
VALID 030343Z - 030445Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 226
CONTINUES.
SUMMARY...STRONGEST STORMS WITH AN ATTENDANT THREAT TO PRODUCE LARGE
HAIL AND DAMAGING WINDS ARE EXPECTED TO REMAIN WITHIN THE SOUTH
CENTRAL TO ERN NEB PORTIONS OF WW 226 THROUGH THE LATE EVENING/EARLY
OVERNIGHT PERIOD.
DISCUSSION...AT 0330Z...REGIONAL RADAR IMAGERY INDICATED THE MOST
INTENSE TSTMS HAD REMAINED OVER SERN NEB /SERN HALL AND NERN ADAMS
COUNTIES INTO CLAY COUNTY/. TRENDS WITH THE STORM IN FILLMORE COUNTY
SUGGEST SOME WEAKENING...POTENTIALLY DUE TO A STRENGTHENING CAP NWD
FROM KS INTO SRN NEB GIVEN THE LOSS OF DAYTIME HEATING.
OTHERWISE...THE STRONGER STORMS FROM CLAY COUNTY TO INVOF HSI MAY BE
JUST FAR ENOUGH N THAT THE STRENGTHENING SLY LLJ FROM OK TO ERN NEB
IS OFFSETTING THE CAP WITH A FEED OF MODERATE TO STRONG MUCAPE.
THE CORRIDOR OF STRONGEST INSTABILITY EXTENDED FROM THE MID MO
VALLEY SWD TO CENTRAL KS...WHILE EFFECTIVE BULK SHEAR OF 35-55 KT
OVER ERN NEB INTO SERN SD/WRN IA/SWRN MN IS MORE THAN SUFFICIENT FOR
ORGANIZED STORMS INCLUDING SUPERCELLS. HOWEVER...THE OVERALL THREAT
FOR SEVERE STORMS WITH NWD EXTENT /INTO NERN NEB AND ADJACENT SERN
SD/NWRN IA/SWRN MN/ APPEARS LIMITED GIVEN ITS DISTANCE AWAY FROM
STRONGER LOW LEVEL INFLOW OVER SRN/SERN NEB. THIS REASONING WOULD
PRECLUDE A NEW WW TO THE N/NE OF WW 226 AT THIS TIME.
..PETERS.. 05/03/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...DMX...FSD...OAX...GID...
LAT...LON 40019737 40099929 41129873 42189784 42889712 43209669
43179579 42489558 41429581 40479654 40019737SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 3, 12:50 AM CDT | Severe Thunderstorm Watch | SPC | Adams, Cass, Fremont, Mills, Montgomery, Page and 2 more | 4 hr |
| May 3, 3:05 AM CDT | Mesoscale Discussion | SPC | Adair, Adams, Cass, Clarke, Decatur, Montgomery and 4 more | 85 min |
| May 3, 2:12 PM CDT | Mesoscale Discussion | SPC | Buena Vista, Calhoun, Cerro Gordo, Cherokee, Clay, Dickinson and 18 more | 2 hr |
| May 3, 3:41 PM CDT | Mesoscale Discussion | SPC | Adair, Adams, Cass, Clarke, Fremont, Madison and 7 more | 2 hr |
| May 3, 6:42 PM CDT | Mesoscale Discussion | SPC | Appanoose, Davis, Decatur, Des Moines, Henry, Lee and 5 more | 63 min |
| May 2, 7:32 PM CDT | Severe Thunderstorm Watch | SPC | Adams, Antelope, Boone, Buffalo, Burt, Butler and 36 more | 6 hr |
| May 2, 7:20 PM CDT | Mesoscale Discussion | SPC | Brown, Campbell, Corson, Day, Dewey, Edmunds and 11 more | 55 min |
| May 2, 11:06 PM CDT | Mesoscale Discussion | SPC | Codington, Day, Grant, Roberts | 24 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.