Alert archive / Tennessee / Mesoscale Discussions in 2016

Mesoscale Discussion 83

February 2, 201628 counties in Alabama; Lowndes County, Mississippi; 32 counties in Tennessee

The Storm Prediction Center issued this mesoscale discussion at Feb 2, 2016, 8:50 PM CST for 28 counties in Alabama; Lowndes County, Mississippi; 32 counties in Tennessee. It was in force for 55 min.

The area

The outline as issued.

The facts

Issued
Feb 2, 2016, 8:50 PM CST (02:50 UTC)
Expired
Feb 2, 2016, 9:45 PM CST
In force
55 min
Issued by
the Storm Prediction Center
All 61 counties

Bibb County, AL, Blount County, AL, Chilton County, AL, Colbert County, AL, Cullman County, AL, Fayette County, AL, Franklin County, AL, Greene County, AL, Hale County, AL, Jackson County, AL, Jefferson County, AL, Lamar County, AL, Lauderdale County, AL, Lawrence County, AL, Limestone County, AL, Madison County, AL, Marengo County, AL, Marion County, AL, Marshall County, AL, Morgan County, AL, Perry County, AL, Pickens County, AL, Shelby County, AL, St. Clair County, AL, Sumter County, AL, Tuscaloosa County, AL, Walker County, AL, Winston County, AL, Lowndes County, MS, Bedford County, TN, Cannon County, TN, Cheatham County, TN, Coffee County, TN, Davidson County, TN, DeKalb County, TN, Dickson County, TN, Franklin County, TN, Giles County, TN, Grundy County, TN, Hickman County, TN, Jackson County, TN, Lawrence County, TN, Lewis County, TN, Lincoln County, TN, Macon County, TN, Marion County, TN, Marshall County, TN, Maury County, TN, Moore County, TN, Putnam County, TN, Robertson County, TN, Rutherford County, TN, Smith 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 Northeast Alabama radar (KHTX), 115 km from the middle of the area, began a volume at 02:50 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

Birmingham, AL (KBMX), launched 00:00Z, 2.8 hours before the alert went out and 126 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, Birmingham, AL at 00:00Z on 2016-02-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 313 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, Birmingham, AL at 00:00Z on 2016-02-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 371 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
313 J/kg
Mixed-layer CIN
-40 J/kg
Mixed-layer LCL
765 m above ground
0-6 km bulk shear
58 kt
0-1 km storm-relative helicity
371 m²/s²
0-3 km storm-relative helicity
518 m²/s²
Significant tornado parameter
0.9
Supercell composite
5.2

Open this sounding in Storm Lab

The text

As transmitted.

379 
ACUS11 KWNS 030251
SWOMCD
SPC MCD 030250 
TNZ000-ALZ000-MSZ000-030345-

MESOSCALE DISCUSSION 0083
NWS STORM PREDICTION CENTER NORMAN OK
0850 PM CST TUE FEB 02 2016

AREAS AFFECTED...MIDDLE TENNESSEE SOUTHWARD INTO WESTERN/CENTRAL
ALABAMA

CONCERNING...TORNADO WATCH 11...

VALID 030250Z - 030345Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 11 CONTINUES.

SUMMARY...ISOLATED WIND DAMAGE/TORNADO THREAT CONTINUES ACROSS WW
11...ESPECIALLY ACROSS WESTERN/CENTRAL ALABAMA.

DISCUSSION...CONTINUE WW 11.  SCATTERED THUNDERSTORMS WITH
OCCASIONAL STRONG LOW-LEVEL ROTATION CONTINUE TO MOVE INTO WESTERN
PARTS OF THE WATCH AREA FROM EASTERN MISSISSIPPI.  OTHER
SHOWERS/ISOLATED THUNDERSTORMS SOUTH OF WW 11 /ACROSS SOUTHWESTERN
ALABAMA/ ALSO CONTINUE TO PERSIST WITHIN CONFLUENT/UNSTABLE WARM
SECTOR FLOW... AND MAY ALSO POSE AN ISOLATED TORNADO THREAT GIVEN
FAVORABLE STORM MODE AND STRONG LOW- AND DEEP-SHEAR.  PORTIONS OF
WESTERN/CENTRAL ALABAMA MAY NEED A NEW WW AS THE TORNADO THREAT IN
THESE AREAS WILL LIKELY PERSIST BEYOND THE 04Z EXPIRATION TIME.

FARTHER NORTH INTO MIDDLE TENNESSEE...WEAKER SURFACE-BASED BUOYANCY
IS LIMITING THE SEVERE THREAT.  HOWEVER...PERSISTENT CONVECTION
CONTAINING LEWP-TYPE STRUCTURES SUGGEST AN ISOLATED WIND GUST OR
BRIEF TORNADO CANNOT BE COMPLETELY RULED AS STORMS ENTER WESTERN
PORTIONS OF WW 11.  THE EXPECTED PERSISTENCE OF THIS CONVECTION
REMAINS IN QUESTION DUE TO MORE MARGINAL THERMODYNAMIC PROFILES. 
TRENDS WILL BE MONITORED...AND IS IT LIKELY THAT MUCH OF WW 11 MAY
BE ALLOWED TO EXPIRE AS CURRENTLY SCHEDULED.

..COOK/THOMPSON.. 02/03/2016

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

ATTN...WFO...MRX...OHX...BMX...HUN...MOB...MEG...JAN...

LAT...LON   32538845 33348857 34618815 36018750 36558702 36648639
            36578576 36468536 35948517 34788570 33278645 32578686
            32268728 32188769 32348823 32538845

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 2, 6:52 PM CSTTornado WatchSPCBaldwin, Choctaw, Clarke, Mobile, Monroe, Washington and 1 more8 hr
Feb 2, 9:59 PM CSTTornado WatchSPCAutauga, Bibb, Chilton, Clay, Coosa, Dallas and 14 more6 hr
Feb 2, 10:23 PM CSTMesoscale DiscussionSPCBaldwin, Choctaw, Clarke, Mobile, Monroe, Washington and 1 more2 hr
Feb 3, 1:30 AM CSTMesoscale DiscussionSPCCalhoun, Clay, Coosa, Elmore, Macon, Talladega and 1 more60 min
Feb 2, 6:13 PM CSTMesoscale DiscussionSPCAlcorn, Attala, Benton, Bolivar, Calhoun, Carroll and 30 more2 hr
Feb 3, 3:58 AM CSTMesoscale DiscussionSPCBlount, Cocke, Grainger, Greene, Hamblen, Hancock and 5 more92 min

Nearby

Mesoscale Discussions in Tennessee, 2016Mesoscale Discussions in Alabama, 2016Mesoscale Discussions in Mississippi, 2016Every mesoscale discussion in 2016

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.