Alert archive / Tennessee / Mesoscale Discussions in 2011
Mesoscale Discussion 482
The Storm Prediction Center issued this mesoscale discussion at Apr 19, 2011, 9:39 PM CDT for Colbert County, Franklin County, Lauderdale County, Alabama; 17 counties in Mississippi; 29 counties in Tennessee. It was in force for 66 min.
The area
The outline as issued.
The facts
- Issued
- Apr 19, 2011, 9:39 PM CDT (02:39 UTC)
- Expired
- Apr 19, 2011, 10:45 PM CDT
- In force
- 66 min
- Issued by
- the Storm Prediction Center
All 49 counties
Colbert County, AL, Franklin County, AL, Lauderdale County, AL, Alcorn County, MS, Benton County, MS, Calhoun County, MS, Chickasaw County, MS, Grenada County, MS, Itawamba County, MS, Lafayette County, MS, Lee County, MS, Marshall County, MS, Panola County, MS, Pontotoc County, MS, Prentiss County, MS, Tallahatchie County, MS, Tippah County, MS, Tishomingo County, MS, Union County, MS, Yalobusha County, MS, Bedford County, TN, Benton County, TN, Cannon County, TN, Carroll County, TN, Cheatham County, TN, Chester County, TN, Davidson County, TN, Decatur County, TN, Dickson County, TN, Giles County, TN, Hardeman County, TN, Hardin County, TN, Henderson County, TN, Hickman County, TN, Houston County, TN, Humphreys County, TN, Lawrence County, TN, Lewis County, TN, Madison County, TN, Marshall County, TN, Maury County, TN, McNairy County, TN, Perry County, TN, Rutherford County, TN, Sumner County, TN, Trousdale County, TN, Wayne County, TN, Williamson County, TN, Wilson County, TN
The watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Little Rock, AR (KLZK), launched 00:00Z, 2.7 hours before the alert went out and 138 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
- 1605 J/kg
- Mixed-layer CIN
- -56 J/kg
- Mixed-layer LCL
- 2015 m above ground
- 0-6 km bulk shear
- 41 kt
- 0-1 km storm-relative helicity
- 173 m²/s²
- 0-3 km storm-relative helicity
- 208 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 10.6
The text
As transmitted, in the capitals the NWS used until 2016.
487
ACUS11 KWNS 200240
SWOMCD
SPC MCD 200239
TNZ000-ALZ000-MSZ000-200345-
MESOSCALE DISCUSSION 0482
NWS STORM PREDICTION CENTER NORMAN OK
0939 PM CDT TUE APR 19 2011
AREAS AFFECTED...NRN MS THROUGH NRN AL AND MIDDLE TN
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 200239Z - 200345Z
A WW WILL LIKELY BE NEEDED BY 03Z FOR PORTIONS OF NRN MS...EXTREME
NWRN AL INTO MIDDLE TN. THREAT WILL EXIST FOR DAMAGING WIND...LARGE
HAIL AND ISOLATED TORNADOES.
EXPANSIVE QLCS EXTENDS FROM NRN IND SWWD THROUGH ERN AR WITH SRN END
MOVING EAST AT 40 KT. THE ATMOSPHERE REMAINS MODERATELY UNSTABLE
EAST OF THE LINE. DESPITE PRESENCE OF A CAPPING INVERSION...DEEPER
FORCING FOR ASCENT WITH PROGRESSIVE SHORTWAVE TROUGH WILL LIKELY
WEAKEN THE CAP ENOUGH FOR STORMS TO CONTINUE DEVELOPING ALONG THE
ADVANCING CONVECTIVE OUTFLOW BOUNDARY. A PREDOMINANT LINEAR MODE
WILL SUPPORT DAMAGING WIND AS PRIMARY THREAT. HOWEVER...SRN
EXTENSION OF A STRONG SLY LLJ WILL MAINTAIN 0-1 KM HODOGRAPHS
SUFFICIENT FOR A LINGERING THREAT OF MESOCYCLONES AND ISOLATED
TORNADOES EMBEDDED WITHIN THE QLCS.
..DIAL.. 04/20/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...OHX...BMX...HUN...MEG...JAN...
LAT...LON 33799073 36418817 36568603 35628606 34428775 33538958
33799073SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 19, 11:56 PM CDT | Mesoscale Discussion | SPC | Colbert, Franklin, Lamar, Lauderdale, Lawrence, Limestone and 4 more | 94 min |
| Apr 20, 3:19 AM CDT | Mesoscale Discussion | SPC | Blount, Calhoun, Cherokee, Cullman, DeKalb, Etowah and 16 more | 86 min |
| Apr 20, 3:37 AM CDT | Severe Thunderstorm Watch | SPC | Bibb, Blount, Calhoun, Chambers, Cherokee, Chilton and 33 more | 8 hr |
| Apr 20, 5:39 AM CDT | Mesoscale Discussion | SPC | Calhoun, Cherokee, Cleburne, St. Clair | 66 min |
| Apr 20, 8:42 AM CDT | Mesoscale Discussion | SPC | Autauga, Bibb, Chilton, Clay, Coosa, Elmore and 11 more | 63 min |
| Apr 20, 1:16 PM CDT | Mesoscale Discussion | SPC | Autauga, Barbour, Bibb, Blount, Bullock, Chambers and 28 more | 89 min |
| Apr 20, 1:33 PM CDT | Severe Thunderstorm Watch | SPC | Autauga, Barbour, Bibb, Bullock, Butler, Chambers and 33 more | 6 hr |
| Apr 20, 5:24 PM CDT | Mesoscale Discussion | SPC | Autauga, Bibb, Chilton, Coosa, Elmore, Fayette and 10 more | 96 min |
| Apr 20, 6:51 PM CDT | Mesoscale Discussion | SPC | Fayette, Greene, Lamar, Marion, Pickens, Tuscaloosa and 2 more | 84 min |
| Apr 19, 10:14 PM CDT | Tornado Watch | SPC | Alcorn, Benton, Bolivar, Calhoun, Carroll, Chickasaw and 24 more | 7 hr |
| Apr 20, 12:46 PM CDT | Mesoscale Discussion | SPC | Bolivar, Carroll, Grenada, Holmes, Humphreys, Issaquena and 6 more | 89 min |
| Apr 20, 1:02 PM CDT | Severe Thunderstorm Watch | SPC | Alcorn, Attala, Benton, Bolivar, Calhoun, Carroll and 52 more | 7 hr |
| Apr 20, 5:56 PM CDT | Mesoscale Discussion | SPC | Bolivar, Calhoun, Chickasaw, Clay, Coahoma, Grenada and 13 more | 2 hr |
| Apr 19, 8:07 PM CDT | Mesoscale Discussion | SPC | Dyer, Lake, Lauderdale, Obion, Tipton | 83 min |
| Apr 20, 1:42 AM CDT | Tornado Watch | SPC | Anderson, Bledsoe, Blount, Bradley, Campbell, Cannon and 42 more | 5 hr |
| Apr 20, 2:20 AM CDT | Mesoscale Discussion | SPC | Anderson, Bledsoe, Campbell, Claiborne, Clay, Cumberland and 23 more | 85 min |
Nearby
Mesoscale Discussions in Tennessee, 2011Mesoscale Discussions in Mississippi, 2011Mesoscale Discussions in Alabama, 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.