Alert archive / Tennessee / Mesoscale Discussions in 2011

Mesoscale Discussion 413

April 11, 20114 states

The Storm Prediction Center issued this mesoscale discussion at Apr 11, 2011, 12:37 PM CDT for 4 states. It was in force for 53 min.

The area

The outline as issued.

The facts

Issued
Apr 11, 2011, 12:37 PM CDT (17:37 UTC)
Expired
Apr 11, 2011, 1:30 PM CDT
In force
53 min
Issued by
the Storm Prediction Center
All 121 counties

Arkansas County, AR, Bradley County, AR, Cleveland County, AR, Crittenden County, AR, Desha County, AR, Drew County, AR, Jefferson County, AR, Lee County, AR, Lincoln County, AR, Monroe County, AR, Phillips County, AR, St. Francis County, AR, Adair County, KY, Allen County, KY, Anderson County, KY, Barren County, KY, Bourbon County, KY, Boyle County, KY, Casey County, KY, Clark County, KY, Clinton County, KY, Cumberland County, KY, Edmonson County, KY, Fayette County, KY, Franklin County, KY, Garrard County, KY, Green County, KY, Hart County, KY, Jessamine County, KY, Larue County, KY, Lincoln County, KY, Logan County, KY, Madison County, KY, Marion County, KY, Mercer County, KY, Metcalfe County, KY, Monroe County, KY, Nelson County, KY, Nicholas County, KY, Pulaski County, KY, Russell County, KY, Scott County, KY, Simpson 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, Bolivar County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Clay County, MS, Coahoma County, MS, DeSoto County, MS, Grenada County, MS, Itawamba County, MS, Lafayette County, MS, Lee County, MS, Leflore County, MS, Marshall County, MS, Monroe County, MS, Montgomery County, MS, Panola County, MS, Pontotoc County, MS, Prentiss County, MS, Quitman County, MS, Sunflower County, MS, Tallahatchie County, MS, Tate County, MS, Tippah County, MS, Tishomingo County, MS, Tunica County, MS, Union County, MS, Washington County, MS, Webster County, MS, Yalobusha County, MS, Benton County, TN, Carroll County, TN, Cheatham County, TN, Chester County, TN, Clay County, TN, Crockett County, TN, Davidson County, TN, Decatur County, TN, Dickson County, TN, Fayette County, TN, Gibson County, TN, Hardeman County, TN, Hardin County, TN, Haywood County, TN, Henderson County, TN, Henry County, TN, Hickman County, TN, Houston County, TN, Humphreys County, TN, Jackson County, TN, Lawrence County, TN, Lewis County, TN, Macon County, TN, Madison County, TN, Maury County, TN, McNairy County, TN, Montgomery County, TN, Overton County, TN, Perry County, TN, Pickett County, TN, Robertson County, TN, Rutherford County, TN, Shelby County, TN, Smith County, TN, Stewart County, TN, Sumner County, TN, Tipton 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

Nashville Metro, TN (KBNA), launched 12:00Z, 5.6 hours before the alert went out and 157 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.

Skew-T log-pSkew-T log-p diagram, Nashville Metro, TN at 12:00Z on 2011-04-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 539 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Nashville Metro, TN at 12:00Z on 2011-04-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 234 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
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

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

694 
ACUS11 KWNS 111738
SWOMCD
SPC MCD 111737
KYZ000-TNZ000-ALZ000-MSZ000-ARZ000-111830-

MESOSCALE DISCUSSION 0413
NWS STORM PREDICTION CENTER NORMAN OK
1237 PM CDT MON APR 11 2011

AREAS AFFECTED...SWRN TN AND FAR NRN MS

CONCERNING...TORNADO WATCH 128...

VALID 111737Z - 111830Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 128 CONTINUES.

INCREASED POTENTIAL FOR A TORNADO EXISTS ACROSS SWRN TN AND FAR NRN
MS DURING THE EARLY AFTERNOON...INCLUDING THE MEMPHIS METRO AREA BY
18Z.

RECENT SURFACE ANALYSIS SHOWED A WIND SHIFT ATTENDANT TO A
CONVECTIVE OUTFLOW BOUNDARY EXTENDING FROM SRN KY SWWD THROUGH
MIDDLE TN AND WSWWD INTO FAR SWRN TN...ALONG AND S OF MEM.  ELY
SURFACE WINDS OVER WRN TN ARE ENHANCING LOW LEVEL SHEAR WITH THE MEM
WSR-88D VWP INDICATING SURFACE-1 KM VALUE CLOSE TO 40 KT AND 0-1 KM
SRH AROUND 375 M2/S2.  AT 1730Z...REGIONAL RADAR IMAGERY SHOWED A
WELL ORGANIZED STORM OVER FAR EAST CENTRAL AR APPROACHING MEM AT 45
KT FROM THE WSW.  AS THIS STORM REACHES THE MEM AREA...THE
AFOREMENTIONED ENHANCED LOW LEVEL SHEAR SUGGESTS A GREATER POTENTIAL
FOR LOW LEVEL STORM ROTATION AND A TORNADO THREAT.

OTHERWISE...EFFECTIVE SRH 200-300 M2/S2 EXTENDS ACROSS WW 128.
LIGHTNING DATA SHOWED TSTMS EXTENDING FROM FAR WRN TN SSWWD THROUGH
ERN TN TO FAR NRN LA.  THIS ACTIVITY WILL PERSIST EWD INTO WW 128
POSING A THREAT FOR DAMAGING WINDS AND A TORNADO THREAT.

..PETERS.. 04/11/2011

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...MRX...JKL...ILN...LMK...OHX...HUN...PAH...MEG...
JAN...LZK...

LAT...LON   33339239 34549208 36258843 36658779 37458595 38388470
            38498397 36708457 34918783 33638859 33198971 33339239

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 10, 7:28 PM CDTTornado WatchSPCBaxter, Benton, Boone, Carroll, Crawford, Franklin and 7 more8 hr
Apr 10, 8:52 PM CDTMesoscale DiscussionSPCBenton, Boone, Carroll, Crawford, Madison, Washington53 min
Apr 11, 1:49 AM CDTTornado WatchSPCHempstead, Howard, Lafayette, Little River, Miller, Nevada and 1 more4 hr
Apr 11, 2:04 AM CDTMesoscale DiscussionSPCBaxter, Benton, Boone, Carroll, Conway, Crawford and 17 more56 min
Apr 11, 4:19 AM CDTMesoscale DiscussionSPCCalhoun, Clark, Cleburne, Cleveland, Columbia, Conway and 28 more56 min
Apr 11, 9:46 AM CDTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Cleveland and 10 more29 min
Apr 11, 10:31 AM CDTTornado WatchSPCArkansas, Bradley, Cleveland, Crittenden, Desha, Drew and 6 more6 hr
Apr 11, 8:58 AM CDTMesoscale DiscussionSPCAdair, Allen, Anderson, Barren, Bourbon, Boyle and 37 more62 min
Apr 11, 10:41 AM CDTMesoscale DiscussionSPCAdair, Allen, Barren, Casey, Clinton, Cumberland and 8 more64 min
Apr 11, 11:24 AM CDTMesoscale DiscussionSPCBoyd, Breathitt, Carter, Clay, Elliott, Estill and 19 more36 min
Apr 11, 11:47 AM CDTTornado WatchSPCBath, Bell, Boyd, Breathitt, Carter, Clay and 31 more6 hr
Apr 11, 2:44 PM CDTMesoscale DiscussionSPCBath, Bell, Boyd, Breathitt, Carter, Clay and 31 more61 min
Apr 11, 5:11 PM CDTTornado WatchSPCAdair, Bell, Breathitt, Casey, Clay, Clinton and 18 more7 hr
Apr 11, 3:56 PM CDTMesoscale DiscussionSPCAlcorn, Attala, Chickasaw, Choctaw, Clarke, Clay and 29 more34 min
Apr 11, 4:05 PM CDTTornado WatchSPCClarke, Covington, Forrest, Greene, Jasper, Jefferson Davis and 20 more6 hr
Apr 11, 6:42 PM CDTMesoscale DiscussionSPCBlount, Bradley, Carter, Cocke, Grainger, Greene and 14 more33 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.