Alert archive / Nebraska / Mesoscale Discussions in 2011
Mesoscale Discussion 2012
The Storm Prediction Center issued this mesoscale discussion at Aug 18, 2011, 8:29 PM CDT for 8 counties in Iowa; 7 counties in Missouri; 23 counties in Nebraska. It was in force for 61 min.
The area
The outline as issued.
The facts
- Issued
- Aug 18, 2011, 8:29 PM CDT (01:29 UTC)
- Expired
- Aug 18, 2011, 9:30 PM CDT
- In force
- 61 min
- Issued by
- the Storm Prediction Center
All 38 counties
Adams County, IA, Cass County, IA, Fremont County, IA, Mills County, IA, Montgomery County, IA, Page County, IA, Pottawattamie County, IA, Taylor County, IA, Andrew County, MO, Atchison County, MO, DeKalb County, MO, Gentry County, MO, Holt County, MO, Nodaway County, MO, Worth County, MO, Antelope County, NE, Boone County, NE, Butler County, NE, Cass County, NE, Colfax County, NE, Cuming County, NE, Dodge County, NE, Douglas County, NE, Johnson County, NE, Lancaster County, NE, Madison County, NE, Nemaha County, NE, Otoe County, NE, Pawnee County, NE, Pierce County, NE, Platte County, NE, Polk County, NE, Richardson County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Stanton County, NE, Washington County, NE
The radar
The Omaha radar (KOAX), 35 km from the middle of the area, began a volume at 01:30 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 nearest sounding before it
Omaha, NE (KOAX), launched 00:00Z, 1.5 hours before the alert went out and 35 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
- 1385 J/kg
- Mixed-layer CIN
- -135 J/kg
- Mixed-layer LCL
- 582 m above ground
- 0-6 km bulk shear
- 66 kt
- 0-1 km storm-relative helicity
- 289 m²/s²
- 0-3 km storm-relative helicity
- 636 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 47.4
The text
As transmitted, in the capitals the NWS used until 2016.
640
ACUS11 KWNS 190129
SWOMCD
SPC MCD 190129
MOZ000-IAZ000-KSZ000-NEZ000-190230-
MESOSCALE DISCUSSION 2012
NWS STORM PREDICTION CENTER NORMAN OK
0829 PM CDT THU AUG 18 2011
AREAS AFFECTED...ERN NEB / SWRN IA / NWRN MO
CONCERNING...TORNADO WATCH 787...
VALID 190129Z - 190230Z
THE SEVERE WEATHER THREAT FOR TORNADO WATCH 787 CONTINUES.
ISOLD TORNADO RISK CONTINUES...WITH THE GREATEST THREAT OVER E-CNTRL
NEB ON THE WRN PERIPHERY OF DEVELOPING MCS. FARTHER E INVOF THE MO
RIVER VALLEY IN FAR ERN/SERN NEB INTO SWRN IA AND NWRN MO...SEVERE
STRAIGHT-LINE WINDS WILL INCREASINGLY BECOME A GREATER CONCERN.
SEVERE 785 WILL BE ALLOWED TO EXPIRE ACROSS WRN-SWRN IA.
RADAR MOSAIC TRENDS OVER THE PAST FEW HOURS HAVE SHOWN CONSIDERABLE
TRENDS TOWARDS STORM CONGLOMERATION DUE TO CONTINUED STORM
DEVELOPMENT/MERGERS OCCURRING ON THE NE-SIDE OF A NW-SE ORIENTED
OUTFLOW BOUNDARY ACROSS E-CNTRL NEB. THE AIRMASS CONTINUES TO
CONVECTIVELY OVERTURN NEAR THE MO RIVER...LEADING TO COLD POOL
MATURATION FOR A SSEWD MOVING STORM CLUSTER/MCS THE NEXT FEW HOURS.
THE FIRST SIGNS OF AN INCREASING LLJ ARE BECOMING APPARENT WITH 30
KTS SAMPLED RECENTLY BY THE KTWX VAD...FAVORING INCREASED MASS
FLUX/ASCENT IN THE REGION WITH TIME. VERY STEEP H7-H5 LAPSE RATES
/9 DEG C PER KM/ SAMPLED BY THE 00Z TOP RAOB WILL SUPPORT A
CONTINUED LARGE-VERY LARGE HAIL THREAT...ESPECIALLY WITH THE MORE
DISCRETE UPDRAFTS. HP SUPERCELLS ALONG THE MO RIVER AS OF 0125Z
WILL LIKELY CONTINUE TO EVOLVE INTO A LINEAR MODE...WITH BOWING
STRUCTURES LIKELY EVOLVING AND PROMOTING SWATHS OF SEVERE
STRAIGHT-LINE WINDS. FARTHER W ALONG THE WRN PERIPHERY OF THE STORM
COMPLEX...A DISCRETE SUPERCELL MOVING SWD ALONG THE OUTFLOW BOUNDARY
SHOULD MAINTAIN SURFACE-BASED INFLOW PARCELS FOR THE NEXT FEW HOURS
AND PERHAPS MAINTAIN AT LEAST SOME ISOLD TORNADO POTENTIAL INTO THE
MID-EVENING HOURS.
..SMITH.. 08/19/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...DMX...EAX...OAX...TOP...GID...
LAT...LON 40079626 41699816 42359822 42399752 41639603 41419468
40139386 39779424 40079626SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 18, 9:52 PM CDT | Mesoscale Discussion | SPC | Fremont, Page | 53 min |
| Aug 18, 8:09 PM CDT | Severe Thunderstorm Watch | SPC | Bates, Benton, Buchanan, Caldwell, Camden, Carroll and 18 more | 7 hr |
| Aug 18, 11:46 PM CDT | Mesoscale Discussion | SPC | Barry, Barton, Bates, Benton, Buchanan, Caldwell and 40 more | 59 min |
| Aug 19, 12:02 AM CDT | Severe Thunderstorm Watch | SPC | Barry, Barton, Benton, Camden, Cedar, Christian and 28 more | 5 hr |
| Aug 19, 1:08 AM CDT | Severe Thunderstorm Watch | SPC | Cole, Crawford, Franklin, Gasconade, Iron, Madison and 5 more | 4 hr |
| Aug 19, 1:38 AM CDT | Mesoscale Discussion | SPC | Barry, Barton, Benton, Camden, Cedar, Christian and 36 more | 67 min |
| Aug 19, 4:08 AM CDT | Mesoscale Discussion | SPC | Barry, Camden, Christian, Crawford, Dallas, Dent and 22 more | 67 min |
| Aug 19, 5:01 PM CDT | Mesoscale Discussion | SPC | Banner, Cheyenne, Kimball, Scotts Bluff, Sioux | 59 min |
Nearby
Mesoscale Discussions in Nebraska, 2011Mesoscale Discussions in Iowa, 2011Mesoscale Discussions in Missouri, 2011Every mesoscale discussion in 2011
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.