Alert archive / Missouri / Mesoscale Discussions in 2011
Mesoscale Discussion 2010
The Storm Prediction Center issued this mesoscale discussion at Aug 18, 2011, 6:00 PM CDT for 11 counties in Kansas; 27 counties in Missouri; 4 counties in Nebraska. It was in force for 60 min.
The area
The outline as issued.
The facts
- Issued
- Aug 18, 2011, 6:00 PM CDT (23:00 UTC)
- Expired
- Aug 18, 2011, 7:00 PM CDT
- In force
- 60 min
- Issued by
- the Storm Prediction Center
All 42 counties
Atchison County, KS, Brown County, KS, Doniphan County, KS, Douglas County, KS, Jackson County, KS, Jefferson County, KS, Johnson County, KS, Leavenworth County, KS, Miami County, KS, Nemaha County, KS, Wyandotte County, KS, Andrew County, MO, Atchison County, MO, Bates County, MO, Benton County, MO, Buchanan County, MO, Caldwell County, MO, Carroll County, MO, Cass County, MO, Clay County, MO, Clinton County, MO, Daviess County, MO, DeKalb County, MO, Gentry County, MO, Harrison County, MO, Henry County, MO, Holt County, MO, Jackson County, MO, Johnson County, MO, Lafayette County, MO, Livingston County, MO, Nodaway County, MO, Pettis County, MO, Platte County, MO, Ray County, MO, Saline County, MO, St. Clair County, MO, Worth County, MO, Johnson County, NE, Nemaha County, NE, Pawnee County, NE, Richardson County, NE
The radar
The Pleasant Hill radar (KEAX), 55 km from the middle of the area, began a volume at 23:01 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
Topeka, KS (KTOP), launched 12:00Z, 11.0 hours before the alert went out and 100 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
- 717 J/kg
- Mixed-layer CIN
- -277 J/kg
- Mixed-layer LCL
- 1077 m above ground
- 0-6 km bulk shear
- 30 kt
- 0-1 km storm-relative helicity
- 85 m²/s²
- 0-3 km storm-relative helicity
- 106 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.0
The text
As transmitted, in the capitals the NWS used until 2016.
641
ACUS11 KWNS 182300
SWOMCD
SPC MCD 182300
MOZ000-KSZ000-NEZ000-190000-
MESOSCALE DISCUSSION 2010
NWS STORM PREDICTION CENTER NORMAN OK
0600 PM CDT THU AUG 18 2011
AREAS AFFECTED...NWRN-WRN MO / FAR NERN KS / EXTREME SERN NEB
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 182300Z - 190000Z
A NEW SEVERE THUNDERSTORM WATCH WILL LIKELY BE NEEDED WITHIN THE
NEXT HOUR OR SO DOWNSTREAM OF WW 785 ACROSS THE NWRN PORTION OF MO
AND ADJACENT PARTS OF KS AND NEB. LARGE TO VERY LARGE HAIL WILL BE
LIKELY INITIALLY THIS EVENING BEFORE STORM MERGERS LEAD TO SOME
CONSOLIDATION AND SEVERE WIND GUSTS GRADUALLY BECOMING A LARGER
THREAT LATER THIS EVENING.
RADAR MOSAIC ACROSS THE LOWER MO RIVER VALLEY SHOWS A CLUSTER OF
SEMI-DISCRETE SUPERCELLS WITH VERY LARGE HAIL /AOA 2 INCHES IN
DIAMETER/ BEING REPORTED. A RADAR FINE LINE SHOWING CONVECTIVE
OUTFLOW FROM THE STORMS NEAR OMA AND WRN IA IS SLOWLY PUSHING WWD
INTO ERN NEB. SEVERAL DISTURBANCES ANALYZED BY THE RUC ARE MOVING
ACROSS THE SD/NEB/WRN IA...AND SHOULD CONTINUE TO SUPPORT BACKGROUND
LARGE SCALE ASCENT ACROSS THE REGION WELL INTO THE OVERNIGHT HOURS
AS THESE FEATURES/STORM MOTIONS PROGRESS TOWARDS THE DISCUSSION AREA
AND AS A 30+ KT LLJ TERMINUS OVERSPREADS THE REGION.
STRONG VENTING HIGH LEVEL FLOW IS CONTRIBUTING TO 40-60 KTS
EFFECTIVE SHEAR...AND WILL MAINTAIN STORM ORGANIZATION AS STORMS
GRADUALLY MERGE AND GROW UPSCALE LATER THIS EVENING. STEEP MID
LEVEL LAPSE RATES /NEAR 9 DEG C PER KM/ PER THE 18Z OAX RAOB ATOP A
MOISTURE RICH BOUNDARY LAYER ARE RESULTING IN STRONG POTENTIAL
INSTABILITY WITH MLCAPE 1500-3000 J/KG---WITH A LARGE TO VERY LARGE
HAIL AND DMGG WIND THREAT DEVELOPING THIS EVENING AND LASTING WELL
INTO THE LATE EVENING/OVERNIGHT HOURS.
..SMITH.. 08/18/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...SGF...EAX...OAX...TOP...
LAT...LON 39059556 40389649 40479552 40549398 39909345 38999292
38099308 37839387 38319485 39059556SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 17, 7:19 PM CDT | Mesoscale Discussion | SPC | Morton, Stanton | 56 min |
| Aug 17, 9:18 PM CDT | Mesoscale Discussion | SPC | Cheyenne | 57 min |
| Aug 18, 5:26 PM CDT | Mesoscale Discussion | SPC | Barton, Edwards, Ellis, Ellsworth, Lincoln, Ness and 6 more | 64 min |
| 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, 2:51 PM CDT | Mesoscale Discussion | SPC | Atchison, Holt, Nodaway, Worth | 84 min |
| Aug 18, 6:18 PM CDT | Mesoscale Discussion | SPC | Atchison, Holt | 27 min |
| Aug 18, 6:38 PM CDT | Tornado Watch | SPC | Andrew, Atchison, Daviess, DeKalb, Gentry, Harrison and 3 more | 5 hr |
| Aug 18, 12:31 PM CDT | Mesoscale Discussion | SPC | Antelope, Boone, Burt, Butler, Cass, Cedar and 21 more | 89 min |
| Aug 18, 1:27 PM CDT | Severe Thunderstorm Watch | SPC | Antelope, Boone, Burt, Cass, Cedar, Colfax and 17 more | 8 hr |
Nearby
Mesoscale Discussions in Missouri, 2011Mesoscale Discussions in Kansas, 2011Mesoscale Discussions in Nebraska, 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.