Alert archive / Tennessee / Mesoscale Discussions in 2011
Mesoscale Discussion 409
The Storm Prediction Center issued this mesoscale discussion at Apr 11, 2011, 8:58 AM CDT for 4 states. It was in force for 62 min.
The area
The outline as issued.
The facts
- Issued
- Apr 11, 2011, 8:58 AM CDT (13:58 UTC)
- Expired
- Apr 11, 2011, 10:00 AM CDT
- In force
- 62 min
- Issued by
- the Storm Prediction Center
All 133 counties
Colbert County, AL, Cullman County, AL, Fayette County, AL, Franklin County, AL, Lamar County, AL, Lauderdale County, AL, Lawrence County, AL, Limestone County, AL, Madison County, AL, Marion County, AL, Morgan County, AL, Walker County, AL, Winston County, AL, Adair County, KY, Allen County, KY, Anderson County, KY, Barren County, KY, Bourbon County, KY, Boyle County, KY, Butler County, KY, Casey County, KY, Christian County, KY, Clark County, KY, Clinton County, KY, Cumberland County, KY, Edmonson County, KY, Estill County, KY, Fayette County, KY, Garrard County, KY, Grayson County, KY, Green County, KY, Hardin County, KY, Hart County, KY, Jackson County, KY, Jessamine County, KY, Larue County, KY, Lincoln County, KY, Logan County, KY, Madison County, KY, Marion County, KY, McCreary County, KY, Mercer County, KY, Metcalfe County, KY, Monroe County, KY, Nelson County, KY, Pulaski County, KY, Rockcastle County, KY, Russell County, KY, Simpson County, KY, Spencer County, KY, Taylor County, KY, Todd County, KY, Warren County, KY, Washington County, KY, Wayne County, KY, Woodford County, KY, Alcorn County, MS, Benton County, MS, Calhoun County, MS, Chickasaw County, MS, Clay County, MS, Grenada County, MS, Itawamba County, MS, Lafayette County, MS, Lee County, MS, Lowndes County, MS, Marshall County, MS, Monroe County, MS, Montgomery County, MS, Oktibbeha County, MS, Panola County, MS, Pontotoc County, MS, Prentiss County, MS, Quitman County, MS, Tallahatchie County, MS, Tate County, MS, Tippah County, MS, Tishomingo County, MS, Union County, MS, Webster County, MS, Yalobusha County, MS, Bedford County, TN, Benton County, TN, Cannon County, TN, Carroll County, TN, Cheatham County, TN, Chester County, TN, Clay County, TN, Coffee County, TN, Cumberland County, TN, Davidson County, TN, Decatur County, TN, DeKalb County, TN, Dickson County, TN, Fayette County, TN, Fentress County, TN, Franklin County, TN, Giles County, TN, Grundy County, TN, Hardeman County, TN, Hardin County, TN, Henderson County, TN, Hickman County, TN, Houston County, TN, Humphreys County, TN, Jackson County, TN, Lawrence County, TN, Lewis County, TN, Lincoln County, TN, Macon County, TN, Madison County, TN, Marion County, TN, Marshall County, TN, Maury County, TN, McNairy County, TN, Montgomery County, TN, Moore County, TN, Overton County, TN, Perry County, TN, Pickett County, TN, Putnam County, TN, Robertson County, TN, Rutherford County, TN, Smith County, TN, Stewart County, TN, Sumner County, TN, Trousdale County, TN, Van Buren County, TN, Warren County, TN, Wayne County, TN, White County, TN, Williamson County, TN, Wilson County, TN
The radar
The Nashville radar (KOHX), 117 km from the middle of the area, began a volume at 14:01 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
Nashville Metro, TN (KBNA), launched 12:00Z, 2.0 hours before the alert went out and 107 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
- 539 J/kg
- Mixed-layer CIN
- -94 J/kg
- Mixed-layer LCL
- 942 m above ground
- 0-6 km bulk shear
- 60 kt
- 0-1 km storm-relative helicity
- 234 m²/s²
- 0-3 km storm-relative helicity
- 233 m²/s²
- Significant tornado parameter
- 0.6
- Supercell composite
- 3.4
The text
As transmitted, in the capitals the NWS used until 2016.
057
ACUS11 KWNS 111359
SWOMCD
SPC MCD 111358
KYZ000-TNZ000-ALZ000-MSZ000-111500-
MESOSCALE DISCUSSION 0409
NWS STORM PREDICTION CENTER NORMAN OK
0858 AM CDT MON APR 11 2011
AREAS AFFECTED...WRN AND CENTRAL KY....WRN AND MIDDLE TN...NRN
MS...AND SERN AR
CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY
VALID 111358Z - 111500Z
A TORNADO WATCH WILL LIKELY BE NEEDED THIS MORNING ACROSS
WRN/CENTRAL KY SWWD THROUGH WRN-MIDDLE TN TO NRN MS/SERN AR.
AT 1340Z...REGIONAL RADAR IMAGERY/LIGHTNING DATA SHOWED TSTMS
EXTENDING FROM FAR SWRN KY SWWD TO THE ARKLATEX REGION. A
LONG-LIVED MCV ATTENDANT TO AN OVERNIGHT/EARLY MORNING CONVECTIVE
COMPLEX WAS SUPPORTING THE NERN EXTENT OF ACTIVITY...CURRENTLY
MOVING INTO FAR WRN TN/FAR SWRN KY. 40-50 KT SWLY LLJ PARALLEL TO
AND LOCATED JUST AHEAD OF THIS ACTIVITY COMBINED WITH LOW LEVEL
DIRECTIONAL SHEAR /0-1 KM SRH 400 M2 PER S2/ AS NOTED ON AREA
WSR-88D VWPS ARE FAVORABLE FOR TORNADOES ALONG WITH DAMAGING WINDS.
OBJECTIVE ANALYSES INDICATED AIR MASS IMMEDIATELY DOWNSTREAM IS
MARGINALLY UNSTABLE AND LIKELY PRECLUDING A GREATER COVERAGE OF
STRONGER TO SEVERE STORMS AT THIS TIME. HOWEVER...12Z LIT SOUNDING
IS LIKELY MOST REPRESENTATIVE OF THE ENVIRONMENT INVOF THE ONGOING
TSTMS...WHICH GIVEN THE THERMODYNAMICS AND KINEMATICS SUPPORTS BOTH
A TORNADO AND DAMAGING WIND THREAT GIVEN ALMOST NON-EXISTENT
INHIBITION.
SWLY LOW LEVEL WINDS ADVECTING 60S SURFACE DEWPOINTS NEWD IN ADVANCE
OF A COMPOSITE OUTFLOW BOUNDARY...WHICH EXTENDED FROM SRN OH TO FAR
WRN KY INTO ERN AR...COMBINED WITH DIABATIC HEATING FILTERED THROUGH
HIGHER CLOUDS WILL AID IN DOWNSTREAM DESTABILIZATION. THIS COMBINED
WITH STRONGER HEIGHT FALLS SPREADING INTO THE MID SOUTH AND TN/OH
VALLEYS AND STRONG WIND FIELDS SUGGESTS A TORNADO WATCH WILL BE
NEEDED THIS MORNING.
..PETERS.. 04/11/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...MRX...JKL...LMK...OHX...BMX...HUN...PAH...MEG...
JAN...
LAT...LON 33739081 34689015 35418938 36498807 37618650 38148531
38358414 37588381 35188555 33438745 33358955 33739081SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 11, 10:41 AM CDT | Mesoscale Discussion | SPC | Colbert, Cullman, Fayette, Franklin, Jackson, Lamar and 9 more | 64 min |
| Apr 11, 3:56 PM CDT | Mesoscale Discussion | SPC | Autauga, Bibb, Blount, Calhoun, Chilton, Choctaw and 32 more | 34 min |
| Apr 11, 4:05 PM CDT | Tornado Watch | SPC | Bibb, Blount, Chilton, Choctaw, Clarke, Dallas and 16 more | 6 hr |
| Apr 11, 5:11 PM CDT | Tornado Watch | SPC | Colbert, Cullman, DeKalb, Franklin, Jackson, Lauderdale and 5 more | 7 hr |
| Apr 11, 5:53 PM CDT | Mesoscale Discussion | SPC | Bibb, Greene, Jefferson, Shelby, Tuscaloosa | 97 min |
| Apr 11, 6:42 PM CDT | Mesoscale Discussion | SPC | Autauga, Bullock, Calhoun, Chambers, Cherokee, Chilton and 12 more | 33 min |
| Apr 11, 10:31 AM CDT | Tornado Watch | SPC | Adair, Allen, Anderson, Barren, Bourbon, Boyle and 26 more | 6 hr |
| Apr 11, 11:24 AM CDT | Mesoscale Discussion | SPC | Boyd, Breathitt, Carter, Clay, Elliott, Estill and 19 more | 36 min |
| Apr 11, 11:47 AM CDT | Tornado Watch | SPC | Bath, Bell, Boyd, Breathitt, Carter, Clay and 31 more | 6 hr |
| Apr 11, 12:37 PM CDT | Mesoscale Discussion | SPC | Adair, Allen, Anderson, Barren, Bourbon, Boyle and 31 more | 53 min |
| Apr 11, 2:44 PM CDT | Mesoscale Discussion | SPC | Bath, Bell, Boyd, Breathitt, Carter, Clay and 31 more | 61 min |
| Apr 11, 9:46 AM CDT | Mesoscale Discussion | SPC | Attala, Benton, Bolivar, Calhoun, Carroll, Chickasaw and 37 more | 29 min |
Nearby
Mesoscale Discussions in Tennessee, 2011Mesoscale Discussions in Kentucky, 2011Mesoscale Discussions in Mississippi, 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.