Alert archive / Tennessee / Mesoscale Discussions in 2011
Mesoscale Discussion 780
The Storm Prediction Center issued this mesoscale discussion at May 13, 2011, 5:03 PM CDT for 14 counties in Alabama; 6 counties in Kentucky; 17 counties in Tennessee. It was in force for 57 min.
The area
The outline as issued.
The facts
- Issued
- May 13, 2011, 5:03 PM CDT (22:03 UTC)
- Expired
- May 13, 2011, 6:00 PM CDT
- In force
- 57 min
- Issued by
- the Storm Prediction Center
All 37 counties
Colbert County, AL, Cullman County, AL, Fayette County, AL, Franklin County, AL, Lamar County, AL, Lauderdale County, AL, Lawrence County, AL, Limestone County, AL, Marion County, AL, Morgan County, AL, Pickens County, AL, Tuscaloosa County, AL, Walker County, AL, Winston County, AL, Christian County, KY, Hopkins County, KY, Logan County, KY, Muhlenberg County, KY, Todd County, KY, Trigg County, KY, Cheatham County, TN, Davidson County, TN, Dickson County, TN, Giles County, TN, Hickman County, TN, Houston County, TN, Humphreys County, TN, Lawrence County, TN, Lewis County, TN, Marshall County, TN, Maury County, TN, Montgomery County, TN, Perry County, TN, Robertson County, TN, Stewart County, TN, Wayne County, TN, Williamson County, TN
The radar
The Northeast Alabama radar (KHTX), 130 km from the middle of the area, began a volume at 22:06 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, 10.1 hours before the alert went out and 153 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
- 1225 J/kg
- Mixed-layer CIN
- -55 J/kg
- Mixed-layer LCL
- 983 m above ground
- 0-6 km bulk shear
- 32 kt
- 0-1 km storm-relative helicity
- 40 m²/s²
- 0-3 km storm-relative helicity
- 35 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.1
The text
As transmitted, in the capitals the NWS used until 2016.
356
ACUS11 KWNS 132204
SWOMCD
SPC MCD 132203
TNZ000-ALZ000-KYZ000-MSZ000-132300-
MESOSCALE DISCUSSION 0780
NWS STORM PREDICTION CENTER NORMAN OK
0503 PM CDT FRI MAY 13 2011
AREAS AFFECTED...LOWER TN VALLEY / NWRN AL
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 132203Z - 132300Z
SOME SEVERE THREAT MAY CONTINUE E OF ONGOING SEVERE WATCH 298 AS THE
AIR MASS OVER THE LOWER TN VALLEY AND NWRN AL SLOWLY RECOVERS IN
WAKE OF THE EARLIER MCS. A WW IS POSSIBLE.
21Z SURFACE ANALYSIS PLACES AN OUTFLOW BOUNDARY DRAPED FROM CNTRL AL
INTO E-CNTRL MS AND THEN EXTENDING NWD TOWARDS THE TN/MS/AL BORDER
REGION. VISIBLE SATELLITE IMAGERY SHOWS AN ABSENCE OF CU OVER NWRN
AL AND WRN MIDDLE TN OWING TO THE STABILIZING INFLUENCE OF THE
EARLIER MCS. THE UPPER LOW OVER MO IS SHIFTING EWD FOCUSING LARGE
SCALE FORCING FOR ASCENT TOWARDS THE REGION.
INCREASING FORCING FOR ASCENT AND AN IMPROVING TROPOSPHERIC WIND
PROFILE /SUPPORTIVE OF ORGANIZED STORMS INCLUDING SUPERCELLS/ MAY
ACT TO IMPROVE STRONG-SEVERE POTENTIAL ACROSS THE AREA. DESPITE
THESE POSITIVES...SUBSTANTIAL SURFACE-BASED CINH /TEMPS ONLY IN THE
UPPER 60S-LOWER 70S/ SHOULD FAVOR A TENDENCY FOR STORMS TO BECOME
ELEVATED AND ROOTED ABOVE THE RELATIVELY COOL/STABLE BOUNDARY LAYER
AS THEY MOVE INTO THE DISCUSSION AREA. THEREFORE...DMGG WIND
POTENTIAL SHOULD LESSEN AS STORMS MOVE EWD FROM WW 298 INTO THE WRN
PARTS OF THE DISCUSSION AREA...WITH LARGE HAIL BECOMING THE PRIMARY
THREAT WITH TIME FOR STORMS THAT ARE ABLE TO REMAIN ROBUST INTO THE
EARLY EVENING HOURS.
..SMITH.. 05/13/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...LMK...OHX...BMX...HUN...PAH...MEG...
LAT...LON 33378827 35168809 36298803 37088791 37368747 37198682
36398651 35108663 33708694 33388719 33098759 33098795
33378827SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 13, 11:22 AM CDT | Mesoscale Discussion | SPC | Cherokee, Etowah | 113 min |
| May 13, 5:54 PM CDT | Severe Thunderstorm Watch | SPC | Colbert, Fayette, Franklin, Greene, Lamar, Lauderdale and 5 more | 6 hr |
| May 13, 12:01 PM CDT | Mesoscale Discussion | SPC | Carlisle, Fulton, Graves, Hickman | 89 min |
| May 13, 12:31 PM CDT | Severe Thunderstorm Watch | SPC | Ballard, Calloway, Carlisle, Fulton, Graves, Hickman and 3 more | 6 hr |
| May 13, 2:44 PM CDT | Mesoscale Discussion | SPC | Ballard, Carlisle, Fulton, Graves, Hickman | 2 hr |
| May 13, 2:47 PM CDT | Mesoscale Discussion | SPC | Harlan, Letcher | 58 min |
| May 13, 12:10 PM CDT | Severe Thunderstorm Watch | SPC | Anderson, Blount, Bradley, Campbell, Carter, Claiborne and 24 more | 6 hr |
Nearby
Mesoscale Discussions in Tennessee, 2011Mesoscale Discussions in Alabama, 2011Mesoscale Discussions in Kentucky, 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.