Alert archive / Tennessee / Mesoscale Discussions in 2012

Mesoscale Discussion 204

March 2, 20127 counties in Alabama; 6 counties in Georgia; 34 counties in Tennessee

The Storm Prediction Center issued this mesoscale discussion at Mar 2, 2012, 9:07 AM CST for 7 counties in Alabama; 6 counties in Georgia; 34 counties in Tennessee. It was in force for 53 min.

The area

The outline as issued.

The facts

Issued
Mar 2, 2012, 9:07 AM CST (15:07 UTC)
Expired
Mar 2, 2012, 10:00 AM CST
In force
53 min
Issued by
the Storm Prediction Center
All 47 counties

DeKalb County, AL, Jackson County, AL, Lawrence County, AL, Limestone County, AL, Madison County, AL, Marshall County, AL, Morgan County, AL, Catoosa County, GA, Chattooga County, GA, Dade County, GA, Murray County, GA, Walker County, GA, Whitfield County, GA, Bedford County, TN, Bledsoe County, TN, Bradley County, TN, Cannon County, TN, Coffee County, TN, Cumberland County, TN, DeKalb County, TN, Fentress County, TN, Franklin County, TN, Giles County, TN, Grundy County, TN, Hamilton County, TN, Jackson County, TN, Lincoln County, TN, Loudon County, TN, Marion County, TN, Marshall County, TN, McMinn County, TN, Meigs County, TN, Moore County, TN, Morgan County, TN, Overton County, TN, Polk County, TN, Putnam County, TN, Rhea County, TN, Roane County, TN, Rutherford County, TN, Scott County, TN, Sequatchie County, TN, Smith County, TN, Van Buren County, TN, Warren County, TN, White County, TN, Wilson County, TN

The radar

The Northeast Alabama radar (KHTX), 54 km from the middle of the area, began a volume at 15:10 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, 3.1 hours before the alert went out and 123 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 2012-03-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1667 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 2012-03-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 175 square meters per square second.1939587897117136Sfc1 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
1667 J/kg
Mixed-layer CIN
-25 J/kg
Mixed-layer LCL
523 m above ground
0-6 km bulk shear
68 kt
0-1 km storm-relative helicity
175 m²/s²
0-3 km storm-relative helicity
169 m²/s²
Significant tornado parameter
0.0
Supercell composite
6.1

Open this sounding in Storm Lab

The text

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

671 
ACUS11 KWNS 021508
SWOMCD
SPC MCD 021507
TNZ000-NCZ000-GAZ000-ALZ000-021600-

MESOSCALE DISCUSSION 0204
NWS STORM PREDICTION CENTER NORMAN OK
0907 AM CST FRI MAR 02 2012

AREAS AFFECTED...NRN AL...MIDDLE/ERN TN...FAR NWRN GA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 021507Z - 021600Z

RADAR TRENDS INDICATE AN INCREASE IN AREAL COVERAGE AND INTENSITY OF
TSTMS ACROSS NRN AL AND MIDDLE TN. THE AREA IS BEING MONITORED FOR A
POSSIBLE TORNADO WATCH.

LOOSELY ORGANIZED TSTMS HAVE INCREASED IN AREAL COVERAGE WITHIN A
WEAK WAA ADVECTION REGIME ACROSS NRN AL INTO PARTS OF MIDDLE TN. 12Z
QAG/BMX SOUNDINGS INDICATE A WEAK STABLE LAYER NEAR 1 KM AGL...BUT
WITH CONTINUED HEATING THE ENVIRONMENT SHOULD BECOME MORE FAVORABLE
FOR SFC BASED PARCELS WITHIN THE NEXT 1-2 HRS. GWX VWP DATA ALSO
SHOW A STRONG/CYCLONICALLY CURVED LOW-LEVEL HODOGRAPH...WITH 0-1 KM
BULK SHEAR NEAR 35 KTS. PRIMARY UNCERTAINTY ATTM IS WITH THE
EVOLUTION OF TSTMS...GIVEN LACK OF ROBUST FORCING
MECHANISMS/MESOSCALE BOUNDARIES...BUT WITH A STRONGLY SHEARED AND
MODERATELY UNSTABLE BACKGROUND ENVIRONMENT...THE POTENTIAL FOR LARGE
HAIL...DMGG WINDS...AND A TORNADO OR TWO WILL EXIST. CONVECTIVE
TRENDS WILL BE MONITORED OVER THE NEXT FEW HRS FOR A POSSIBLE
TORNADO WATCH.

..ROGERS.. 03/02/2012

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

ATTN...WFO...MRX...FFC...OHX...BMX...HUN...

LAT...LON   35888425 35038426 34308550 34158620 34168757 34568792
            35998670 36478586 36548448 35888425

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 2, 9:25 AM CSTTornado WatchSPCDeKalb, Jackson, Lawrence, Limestone, Madison, Marshall and 1 more5 hr
Mar 2, 11:46 AM CSTMesoscale DiscussionSPCDeKalb, Jackson, Madison, Marshall, Morgan29 min
Mar 2, 12:57 PM CSTMesoscale DiscussionSPCColbert, Fayette, Franklin, Lamar, Lauderdale, Lawrence and 2 more63 min
Mar 2, 1:20 PM CSTTornado WatchSPCBlount, Colbert, Cullman, DeKalb, Fayette, Franklin and 14 more9 hr
Mar 2, 2:42 PM CSTMesoscale DiscussionSPCAutauga, Baldwin, Bullock, Butler, Choctaw, Clarke and 18 more63 min
Mar 2, 3:25 PM CSTMesoscale DiscussionSPCColbert, Cullman, Fayette, Franklin, Lamar, Lauderdale and 9 more65 min
Mar 2, 4:37 PM CSTTornado WatchSPCAutauga, Baldwin, Barbour, Bibb, Blount, Bullock and 50 more7 hr
Mar 2, 5:41 PM CSTMesoscale DiscussionSPCAutauga, Barbour, Bibb, Blount, Bullock, Butler and 36 more2 hr
Mar 2, 2:30 AM CSTMesoscale DiscussionSPCBanks, Dawson, Fannin, Franklin, Gilmer, Habersham and 8 more90 min
Mar 2, 1:58 PM CSTMesoscale DiscussionSPCBartow, Catoosa, Cherokee, Dawson, Fannin, Forsyth and 14 more62 min
Mar 2, 2:19 PM CSTTornado WatchSPCBanks, Bartow, Catoosa, Chattooga, Cherokee, Dade and 23 more8 hr
Mar 2, 3:40 AM CSTMesoscale DiscussionSPCClay, Fentress, Overton, Pickett, Scott65 min
Mar 2, 9:22 AM CSTMesoscale DiscussionSPCBenton, Carroll, Cheatham, Chester, Crockett, Davidson and 28 more113 min
Mar 2, 10:28 AM CSTMesoscale DiscussionSPCCrockett, Dyer, Fayette, Gibson, Haywood, Lake and 5 more62 min
Mar 2, 12:05 PM CSTMesoscale DiscussionSPCBenton, Carroll, Cheatham, Chester, Crockett, Davidson and 28 more85 min
Mar 2, 2:35 PM CSTMesoscale DiscussionSPCClay, Macon, Pickett, Sumner85 min

Nearby

Mesoscale Discussions in Tennessee, 2012Mesoscale Discussions in Alabama, 2012Mesoscale Discussions in Georgia, 2012Every mesoscale discussion in 2012

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.