Alert archive / Tennessee / Mesoscale Discussions in 2012
Mesoscale Discussion 458
The Storm Prediction Center issued this mesoscale discussion at Apr 5, 2012, 1:54 PM EDT for 17 counties in Georgia; 7 counties in North Carolina; 29 counties in Tennessee. It was in force for 96 min.
The area
The outline as issued.
The facts
- Issued
- Apr 5, 2012, 1:54 PM EDT (17:54 UTC)
- Expired
- Apr 5, 2012, 3:30 PM EDT
- In force
- 96 min
- Issued by
- the Storm Prediction Center
All 53 counties
Bartow County, GA, Catoosa County, GA, Chattooga County, GA, Cherokee County, GA, Dade County, GA, Dawson County, GA, Fannin County, GA, Floyd County, GA, Gilmer County, GA, Gordon County, GA, Lumpkin County, GA, Murray County, GA, Pickens County, GA, Towns County, GA, Union County, GA, Walker County, GA, Whitfield County, GA, Cherokee County, NC, Clay County, NC, Graham County, NC, Haywood County, NC, Macon County, NC, Madison County, NC, Swain County, NC, Anderson County, TN, Bledsoe County, TN, Blount County, TN, Bradley County, TN, Campbell County, TN, Claiborne County, TN, Cocke County, TN, Cumberland County, TN, Grainger County, TN, Greene County, TN, Hamblen County, TN, Hamilton County, TN, Hancock County, TN, Hawkins County, TN, Jefferson County, TN, Knox County, TN, Loudon County, TN, Marion County, TN, McMinn County, TN, Meigs County, TN, Monroe County, TN, Morgan County, TN, Polk County, TN, Rhea County, TN, Roane County, TN, Scott County, TN, Sequatchie County, TN, Sevier County, TN, Union County, TN
The radar
The Knoxville radar (KMRX), 134 km from the middle of the area, began a volume at 17:57 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, 5.9 hours before the alert went out and 206 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
- 670 J/kg
- Mixed-layer CIN
- -22 J/kg
- Mixed-layer LCL
- 805 m above ground
- 0-6 km bulk shear
- 25 kt
- 0-1 km storm-relative helicity
- -15 m²/s²
- 0-3 km storm-relative helicity
- 57 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 0.6
The text
As transmitted, in the capitals the NWS used until 2016.
040
ACUS11 KWNS 051754
SWOMCD
SPC MCD 051754
TNZ000-NCZ000-VAZ000-GAZ000-KYZ000-ALZ000-051930-
MESOSCALE DISCUSSION 0458
NWS STORM PREDICTION CENTER NORMAN OK
1254 PM CDT THU APR 05 2012
AREAS AFFECTED...ERN TN...NRN GA
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 051754Z - 051930Z
CONVECTIVE TRENDS WILL BE MONITORED DURING THE AFTERNOON FOR
POSSIBLE WW OVER PORTIONS OF ERN TN AND NRN GA.
COLD CORE MIDLEVEL LOW WAS LOCATED OVER NERN AR AT 17-18Z...AND IS
FORECAST TO MOVE INTO MIDDLE TN AND NRN AL BY EVENING. AT THE
SURFACE...LOW PRESSURE WAS POSITIONED OVER WRN TN...WITH A
QUASI-STATIONARY FRONTAL BOUNDARY EXTENDING EWD INTO ERN TN...WRN NC
AND NRN SC. AS THE MIDLEVEL LOW ADVANCES EWD DURING THE DAY...THE
SURFACE FRONT MAY SAG SWD TOWARD SERN TN/NRN GA AS SURFACE LOW
PRESSURE REDEVELOPS NEAR COASTAL SC/GA. LATEST OBJECTIVE ANALYSIS
GUIDANCE INDICATES AIRMASS OVER MIDDLE/ERN TN IS EXPERIENCING MODEST
DESTABILIZATION AS TEMPERATURES SLOWLY WARM INTO THE 70S. AS A
RESULT...MLCAPE VALUES HAVE INCREASED TO AROUND 500-1000
J/KG...WHICH IS SUPPORTING SCATTERED THUNDERSTORM DEVELOPMENT INVOF
THE SURFACE FRONT. IN ADDITION...MIDLEVEL SWLYS AHEAD OF THE CLOSED
LOW ARE AROUND 30-40 KT...WHICH WILL AID IN MARGINAL STORM
ORGANIZATION. SOME OF THIS ACTIVITY WILL LIKELY POSE A RISK OF
DAMAGING WIND GUSTS AND LARGE HAIL...WITH THE THREAT POSSIBLY
SPREADING SWD LATER IN THE AFTERNOON TOWARD NRN GA WITH THE
ADVANCING FRONT.
..GARNER.. 04/05/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...GSP...MRX...JKL...FFC...OHX...BMX...HUN...
LAT...LON 35018583 36608474 36598301 35988258 34258417 34158543
35018583SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 5, 1:03 PM EDT | Mesoscale Discussion | SPC | Banks, Burke, Clarke, Columbia, Effingham, Elbert and 24 more | 87 min |
| Apr 5, 1:47 PM EDT | Severe Thunderstorm Watch | SPC | Bryan, Bulloch, Burke, Candler, Chatham, Columbia and 17 more | 7 hr |
| Apr 5, 2:12 PM EDT | Mesoscale Discussion | SPC | Baker, Calhoun, Chattahoochee, Clay, Coweta, Crawford and 30 more | 93 min |
| Apr 5, 2:58 PM EDT | Severe Thunderstorm Watch | SPC | Baker, Ben Hill, Calhoun, Chattahoochee, Clay, Colquitt and 36 more | 6 hr |
| Apr 5, 3:37 PM EDT | Mesoscale Discussion | SPC | Burke, Chatham, Columbia, Effingham, Elbert, Franklin and 11 more | 53 min |
| Apr 5, 4:49 PM EDT | Mesoscale Discussion | SPC | Atkinson, Baker, Ben Hill, Berrien, Brooks, Calhoun and 33 more | 86 min |
| Apr 5, 6:35 PM EDT | Mesoscale Discussion | SPC | Bryan, Bulloch, Burke, Candler, Chatham, Columbia and 12 more | 85 min |
| Apr 5, 7:15 PM EDT | Mesoscale Discussion | SPC | Heard | 45 min |
| Apr 5, 2:21 PM EDT | Severe Thunderstorm Watch | SPC | Cherokee, Clay | 8 hr |
| Apr 5, 4:06 PM EDT | Mesoscale Discussion | SPC | Cherokee, Clay | 54 min |
| Apr 5, 1:09 PM EDT | Mesoscale Discussion | SPC | Bedford, Benton, Cannon, Carroll, Cheatham, Chester and 40 more | 96 min |
| Apr 5, 1:18 PM EDT | Severe Thunderstorm Watch | SPC | Carroll, Chester, Crockett, Decatur, Dyer, Fayette and 14 more | 5 hr |
| Apr 5, 3:22 PM EDT | Mesoscale Discussion | SPC | Benton, Carroll, Chester, Crockett, Decatur, Dyer and 16 more | 53 min |
Nearby
Mesoscale Discussions in Tennessee, 2012Mesoscale Discussions in Georgia, 2012Mesoscale Discussions in North Carolina, 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.