Alert archive / Tennessee / Mesoscale Discussions in 2011
Mesoscale Discussion 918
The Storm Prediction Center issued this mesoscale discussion at May 24, 2011, 5:24 AM CDT for 24 counties in Kentucky; 33 counties in Tennessee. It was in force for 96 min.
The area
The outline as issued.
The facts
- Issued
- May 24, 2011, 5:24 AM CDT (10:24 UTC)
- Expired
- May 24, 2011, 7:00 AM CDT
- In force
- 96 min
- Issued by
- the Storm Prediction Center
All 57 counties
Adair County, KY, Allen County, KY, Barren County, KY, Bell County, KY, Casey County, KY, Clay County, KY, Clinton County, KY, Cumberland County, KY, Harlan County, KY, Jackson County, KY, Knox County, KY, Laurel County, KY, Leslie County, KY, Lincoln County, KY, McCreary County, KY, Metcalfe County, KY, Monroe County, KY, Owsley County, KY, Perry County, KY, Pulaski County, KY, Rockcastle County, KY, Russell County, KY, Wayne County, KY, Whitley County, KY, Anderson County, TN, Bledsoe County, TN, Campbell County, TN, Cannon County, TN, Claiborne County, TN, Clay County, TN, Coffee County, TN, Cumberland County, TN, Davidson County, TN, DeKalb County, TN, Fentress County, TN, Grainger County, TN, Grundy County, TN, Jackson County, TN, Knox County, TN, Macon County, TN, Morgan County, TN, Overton County, TN, Pickett County, TN, Putnam County, TN, Rhea County, TN, Roane County, TN, Rutherford County, TN, Scott County, TN, Smith County, TN, Sumner County, TN, Trousdale County, TN, Union County, TN, Van Buren County, TN, Warren County, TN, White County, TN, Williamson County, TN, Wilson County, TN
The radar
The Nashville radar (KOHX), 113 km from the middle of the area, began a volume at 10:26 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
Nashville Metro, TN (KBNA), launched 00:00Z, 10.4 hours before the alert went out and 120 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
- 1402 J/kg
- Mixed-layer CIN
- -74 J/kg
- Mixed-layer LCL
- 1214 m above ground
- 0-6 km bulk shear
- 56 kt
- 0-1 km storm-relative helicity
- 181 m²/s²
- 0-3 km storm-relative helicity
- 213 m²/s²
- Significant tornado parameter
- 1.1
- Supercell composite
- 7.3
The text
As transmitted, in the capitals the NWS used until 2016.
612
ACUS11 KWNS 241025
SWOMCD
SPC MCD 241024
KYZ000-VAZ000-TNZ000-241200-
MESOSCALE DISCUSSION 0918
NWS STORM PREDICTION CENTER NORMAN OK
0524 AM CDT TUE MAY 24 2011
AREAS AFFECTED...MIDDLE/EASTERN TN INTO SOUTHERN/EASTERN KY
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 241024Z - 241200Z
A SEVERE THREAT IN THE FORM OF HAIL/PERHAPS DAMAGING WINDS...AT
LEAST ON AN ISOLATED BASIS...WILL CONTINUE TO SPREAD
EAST-NORTHEASTWARD THIS MORNING ACROSS MIDDLE/EASTERN TN INTO
SOUTHERN/EASTERN KY.
A FORWARD PROPAGATING/NORTHEASTWARD MOVING CLUSTER OF TSTMS HAS
EVOLVED INTO MIDDLE TN OVER THE PAST 1-2 HOURS. THIS ACTIVITY IS
OCCURRING ON THE NORTHERN EDGE OF STRONG MIXED LAYER ALOFT/CORRIDOR
OF MODERATE ELEVATED INSTABILITY...AS PER REGIONAL 00Z OBSERVED
RAOBS AND MORE CONTEMPORARY RUC SOUNDINGS. WITH SOURCE REGION MUCAPE
ESTIMATED TO BE ON THE ORDER OF 1500-2500 J/KG...MARGINALLY SEVERE
HAIL WILL LIKELY BE THE DOMINANT CONCERN. A RELATIVELY STABLE
BOUNDARY LAYER AND MODEST POTENTIAL FOR EVAPORATIVE COOLING /PER RUC
SOUNDINGS/ SHOULD LIMIT THE SEVERE WIND THREAT...ALTHOUGH MODERATELY
STRONG MEAN SOUTHWESTERLY FLOW/RELATIVELY STEEP LAPSE RATES ALOFT
MAY CONTRIBUTE TO SOME STRONGER DOWNDRAFTS TO THE SURFACE.
..GUYER.. 05/24/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...MRX...JKL...LMK...OHX...HUN...
LAT...LON 35968721 37038625 37618435 37298294 36118339 35238591
35968721SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 23, 7:31 PM CDT | Severe Thunderstorm Watch | SPC | Bath, Boyd, Carter, Elliott, Fleming, Greenup and 6 more | 3 hr |
| May 23, 7:47 PM CDT | Mesoscale Discussion | SPC | Adair, Allen, Barren, Butler, Caldwell, Christian and 21 more | 58 min |
| May 24, 6:01 AM CDT | Severe Thunderstorm Watch | SPC | Adair, Allen, Barren, Bell, Breathitt, Casey and 38 more | 8 hr |
| May 24, 7:34 AM CDT | Mesoscale Discussion | SPC | Bell, Breathitt, Clay, Floyd, Harlan, Jackson and 13 more | 116 min |
| May 24, 11:55 AM CDT | Mesoscale Discussion | SPC | Adair, Allen, Barren, Bell, Clay, Clinton and 15 more | 65 min |
| May 24, 12:57 PM CDT | Severe Thunderstorm Watch | SPC | Adair, Allen, Barren, Bell, Clay, Clinton and 14 more | 6 hr |
| May 24, 2:33 PM CDT | Mesoscale Discussion | SPC | Harlan | 87 min |
| May 24, 3:27 PM CDT | Mesoscale Discussion | SPC | Bell, Harlan, Letcher, Whitley | 63 min |
| May 24, 6:46 PM CDT | Mesoscale Discussion | SPC | Anderson, Bledsoe, Blount, Campbell, Carter, Claiborne and 26 more | 59 min |
Nearby
Mesoscale Discussions in Tennessee, 2011Mesoscale Discussions in Kentucky, 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.