Alert archive / Tennessee / Mesoscale Discussions in 2011
Mesoscale Discussion 939
The Storm Prediction Center issued this mesoscale discussion at May 24, 2011, 7:46 PM EDT for 32 counties in Tennessee; 7 counties in Virginia. It was in force for 59 min.
The area
The outline as issued.
The facts
- Issued
- May 24, 2011, 7:46 PM EDT (23:46 UTC)
- Expired
- May 24, 2011, 8:45 PM EDT
- In force
- 59 min
- Issued by
- the Storm Prediction Center
All 39 counties
Anderson County, TN, Bledsoe County, TN, Blount County, TN, Campbell County, TN, Carter County, TN, Claiborne County, TN, Cocke County, TN, Cumberland County, TN, Fentress County, TN, Grainger County, TN, Greene County, TN, Hamblen County, TN, Hancock County, TN, Hawkins County, TN, Jefferson County, TN, Johnson County, TN, Knox County, TN, Loudon County, TN, Morgan County, TN, Overton County, TN, Pickett County, TN, Putnam County, TN, Rhea County, TN, Roane County, TN, Scott County, TN, Sevier County, TN, Sullivan County, TN, Unicoi County, TN, Union County, TN, Van Buren County, TN, Washington County, TN, White County, TN, City of Bristol, VA, City of Norton, VA, Lee County, VA, Russell County, VA, Scott County, VA, Washington County, VA, Wise County, VA
The radar
The Knoxville radar (KMRX), 57 km from the middle of the area, began a volume at 23:47 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 nearest sounding before it
Nashville Metro, TN (KBNA), launched 12:00Z, 11.8 hours before the alert went out and 231 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
- 739 J/kg
- Mixed-layer CIN
- -100 J/kg
- Mixed-layer LCL
- 768 m above ground
- 0-6 km bulk shear
- 46 kt
- 0-1 km storm-relative helicity
- 181 m²/s²
- 0-3 km storm-relative helicity
- 196 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 3.5
The text
As transmitted, in the capitals the NWS used until 2016.
831
ACUS11 KWNS 242346
SWOMCD
SPC MCD 242346
VAZ000-NCZ000-TNZ000-KYZ000-250045-
MESOSCALE DISCUSSION 0939
NWS STORM PREDICTION CENTER NORMAN OK
0646 PM CDT TUE MAY 24 2011
AREAS AFFECTED...PORTIONS OF NERN/MIDDLE TN AND FAR SWRN VA
CONCERNING...SEVERE THUNDERSTORM WATCH 357...
VALID 242346Z - 250045Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 357
CONTINUES.
AN OUTFLOW BOUNDARY EXTENDS E-W ACROSS PORTIONS OF ERN/MIDDLE
TN...WHERE ISOLATED TO SCATTERED THUNDERSTORMS ARE ONGOING.
OBJECTIVE ANALYSIS AND RECENT SURFACE OBSERVATIONS INDICATE NERN TN
AND FAR SWRN VA ARE QUICKLY STABILIZING IN THE WAKE OF AFTERNOON
STORM ACTIVITY. FARTHER W OVER MIDDLE TN...TEMPERATURES REMAIN IN
THE UPPER 70S/LOW 80S...WITH DEWPOINTS IN THE UPPER 60S CONTRIBUTING
TOWARD MLCAPE VALUES FROM 1000-2000 J/KG. HOWEVER...WITH SHORTWAVE
RIDGING BEGINNING TO OCCUR ACROSS TN...ADDITIONAL THUNDERSTORM
DEVELOPMENT ALONG THE OUTFLOW BOUNDARY IS QUESTIONABLE.
THEREFORE...MARGINAL SVR WEATHER THREAT /MAINLY LARGE HAIL AND
DAMAGING WINDS/ WILL CONTINUE IN THE SHORT TERM...BEFORE STORMS
WEAKEN DURING THE NEXT FEW HRS AS THE BOUNDARY LAYER COOLS.
..GARNER.. 05/24/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...RNK...RLX...GSP...MRX...JKL...OHX...
LAT...LON 36618525 36578372 37178257 36968233 37208176 36338176
35768298 35488393 35698470 35368521 35528543 35848569
36208581 36618525SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 23, 8:47 PM EDT | Mesoscale Discussion | SPC | Bedford, Benton, Cannon, Cheatham, Chester, Clay and 32 more | 58 min |
| May 24, 6:24 AM EDT | Mesoscale Discussion | SPC | Anderson, Bledsoe, Campbell, Cannon, Claiborne, Clay and 27 more | 96 min |
| May 24, 7:01 AM EDT | Severe Thunderstorm Watch | SPC | Anderson, Bledsoe, Blount, Campbell, Cannon, Carter and 40 more | 8 hr |
| May 24, 8:34 AM EDT | Mesoscale Discussion | SPC | Anderson, Bledsoe, Blount, Campbell, Carter, Claiborne and 23 more | 116 min |
| May 24, 12:55 PM EDT | Mesoscale Discussion | SPC | Anderson, Campbell, Claiborne, Clay, Cumberland, Davidson and 25 more | 65 min |
| May 24, 1:57 PM EDT | Severe Thunderstorm Watch | SPC | Anderson, Bedford, Bledsoe, Blount, Campbell, Cannon and 44 more | 6 hr |
| May 24, 3:33 PM EDT | Mesoscale Discussion | SPC | Carter, Greene, Hancock, Hawkins, Johnson, Sullivan and 2 more | 87 min |
| May 24, 4:27 PM EDT | Mesoscale Discussion | SPC | Anderson, Campbell, Carter, Claiborne, Fentress, Grainger and 14 more | 63 min |
| May 24, 10:00 AM EDT | Severe Thunderstorm Watch | SPC | Alleghany, Amherst, Appomattox, Bath, Bedford, Bland and 31 more | 7 hr |
| May 24, 12:15 PM EDT | Mesoscale Discussion | SPC | Amelia, Amherst, Appomattox, Bedford, Botetourt, Brunswick and 41 more | 90 min |
| May 24, 12:42 PM EDT | Severe Thunderstorm Watch | SPC | Accomack, Albemarle, Amelia, Augusta, Brunswick, Caroline and 66 more | 5 hr |
| May 24, 4:43 PM EDT | Tornado Watch | SPC | Bland, Carroll, Floyd, Franklin, Giles, Grayson and 13 more | 5 hr |
| May 24, 7:33 PM EDT | Mesoscale Discussion | SPC | Bland, Carroll, Charlotte, Floyd, Franklin, Grayson and 13 more | 57 min |
Nearby
Mesoscale Discussions in Tennessee, 2011Mesoscale Discussions in Virginia, 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.