Alert archive / Nebraska / Mesoscale Discussions in 2011
Mesoscale Discussion 2005
The Storm Prediction Center issued this mesoscale discussion at Aug 18, 2011, 2:51 PM CDT for 15 counties in Iowa; 4 counties in Missouri; 30 counties in Nebraska. It was in force for 84 min.
The area
The outline as issued.
The facts
- Issued
- Aug 18, 2011, 2:51 PM CDT (19:51 UTC)
- Expired
- Aug 18, 2011, 4:15 PM CDT
- In force
- 84 min
- Issued by
- the Storm Prediction Center
All 49 counties
Adair County, IA, Adams County, IA, Audubon County, IA, Cass County, IA, Fremont County, IA, Guthrie County, IA, Harrison County, IA, Mills County, IA, Montgomery County, IA, Page County, IA, Pottawattamie County, IA, Ringgold County, IA, Shelby County, IA, Taylor County, IA, Union County, IA, Atchison County, MO, Holt County, MO, Nodaway County, MO, Worth County, MO, Antelope County, NE, Boone County, NE, Burt County, NE, Butler County, NE, Cass County, NE, Colfax County, NE, Cuming County, NE, Dodge County, NE, Douglas County, NE, Gage County, NE, Johnson County, NE, Knox County, NE, Lancaster County, NE, Madison County, NE, Nance County, NE, Nemaha County, NE, Otoe County, NE, Pawnee County, NE, Pierce 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, Washington County, NE, Wayne County, NE, York County, NE
The radar
The Omaha radar (KOAX), 30 km from the middle of the area, began a volume at 19:50 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, 7.9 hours before the alert went out and 30 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
- 1181 J/kg
- Mixed-layer CIN
- -126 J/kg
- Mixed-layer LCL
- 683 m above ground
- 0-6 km bulk shear
- 47 kt
- 0-1 km storm-relative helicity
- 234 m²/s²
- 0-3 km storm-relative helicity
- 385 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 11.7
The text
As transmitted, in the capitals the NWS used until 2016.
999
ACUS11 KWNS 181952
SWOMCD
SPC MCD 181951
MOZ000-IAZ000-NEZ000-SDZ000-182115-
MESOSCALE DISCUSSION 2005
NWS STORM PREDICTION CENTER NORMAN OK
0251 PM CDT THU AUG 18 2011
AREAS AFFECTED...PARTS ERN NEB INTO WRN IA...NRN MO
CONCERNING...SEVERE THUNDERSTORM WATCH 785...
VALID 181951Z - 182115Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 785
CONTINUES.
AREAS WEST AND SOUTH OF WW 785 ARE BEING MONITORED FOR THE
POSSIBILITY OF AN ADDITIONAL WW OR TWO LATE THIS AFTERNOON.
STRONGEST LOWER/MID TROPOSPHERIC WARM ADVECTION REMAINS FOCUSED ON
THE SOUTHERN AND WESTERN FLANK OF ONGOING CONVECTIVE ACTIVITY ACROSS
THE MID MISSOURI VALLEY. NEW STORMS BEGINNING TO FORM WITHIN THIS
ZONE DURING THE NEXT FEW HOURS WILL PRODUCE OUTFLOW THAT SHOULD
BEGIN TO CONSOLIDATE AND SURGE SOUTHWARD ACROSS EASTERN NEBRASKA AND
SOUTHWESTERN IOWA...AIDED BY MODEST SOUTH SOUTHWESTERLY LOW-LEVEL
FLOW /AROUND 20 KT AT 850 MB/. INHIBITION FOR MOIST BOUNDARY LAYER
PARCELS CHARACTERIZED BY LOWER/MID 70S SURFACE DEW POINTS IS
BECOMING INCREASINGLY NEGLIGIBLE ACROSS THIS REGION...WITH MIXED
LAYER CAPE NOW ON THE ORDER OF 3000-4000 J/KG. THIS SHOULD SUPPORT
SIGNIFICANT FURTHER CONVECTIVE INTENSIFICATION AND UPSCALE GROWTH
INTO AN INCREASINGLY ORGANIZED MESOSCALE CONVECTIVE SYSTEM THAT
COULD IMPACT THE OMAHA/LINCOLN AREA BY 22/23Z. THIS WILL BE
ACCOMPANIED BY AN INCREASING RISK FOR STRONG DAMAGING WIND
GUSTS...PERHAPS ISOLATED BRIEF TORNADOES.
..KERR.. 08/18/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...DMX...EAX...FSD...OAX...GID...LBF...
LAT...LON 41909464 41299423 40729413 40319439 40079482 40019568
40109691 40779765 41529813 42649855 42809785 42129670
41909464SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 18, 12:31 PM CDT | Mesoscale Discussion | SPC | Crawford, Harrison, Ida, Mills, Monona, Plymouth and 3 more | 89 min |
| Aug 18, 1:27 PM CDT | Severe Thunderstorm Watch | SPC | Adair, Adams, Audubon, Carroll, Cass, Cherokee and 17 more | 8 hr |
| Aug 18, 6:18 PM CDT | Mesoscale Discussion | SPC | Fremont, Harrison, Mills, Monona, Montgomery, Page and 2 more | 27 min |
| Aug 18, 6:38 PM CDT | Tornado Watch | SPC | Fremont, Mills, Page | 5 hr |
| Aug 18, 7:41 AM CDT | Mesoscale Discussion | SPC | Douglas, Howell, Oregon, Ozark, Ripley | 3 hr |
| Aug 18, 2:40 PM CDT | Mesoscale Discussion | SPC | Bollinger, Cape Girardeau, Madison, Mississippi, Perry, Scott and 2 more | 2 hr |
| Aug 18, 6:00 PM CDT | Mesoscale Discussion | SPC | Andrew, Atchison, Bates, Benton, Buchanan, Caldwell and 21 more | 60 min |
| Aug 17, 9:18 PM CDT | Mesoscale Discussion | SPC | Blaine, Brown, Chase, Cherry, Dundy, Frontier and 10 more | 57 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.