Alert archive / Tennessee / Mesoscale Discussions in 2012
Mesoscale Discussion 2069
The Storm Prediction Center issued this mesoscale discussion at Oct 17, 2012, 8:07 PM CDT for Calloway County, Kentucky; Alcorn County, Mississippi; 21 counties in Tennessee. It was in force for 53 min.
The area
The outline as issued.
The facts
- Issued
- Oct 17, 2012, 8:07 PM CDT (01:07 UTC)
- Expired
- Oct 17, 2012, 9:00 PM CDT
- In force
- 53 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 80%
All 23 counties
Calloway County, KY, Alcorn County, MS, Benton County, TN, Carroll County, TN, Chester County, TN, Decatur County, TN, Dickson County, TN, Gibson County, TN, Hardeman County, TN, Hardin County, TN, Henderson County, TN, Henry County, TN, Hickman County, TN, Houston County, TN, Humphreys County, TN, Lewis County, TN, Madison County, TN, McNairy County, TN, Montgomery County, TN, Perry County, TN, Stewart County, TN, Wayne County, TN, Weakley County, TN
The radar
The Memphis radar (KNQA), 150 km from the middle of the area, began a volume at 01:09 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 00:00Z, 1.1 hours before the alert went out and 161 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1963 m above ground
- 0-6 km bulk shear
- 37 kt
- 0-1 km storm-relative helicity
- 169 m²/s²
- 0-3 km storm-relative helicity
- 300 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
344 ACUS11 KWNS 180108 SWOMCD SPC MCD 180107 TNZ000-KYZ000-ALZ000-MSZ000-180200- MESOSCALE DISCUSSION 2069 NWS STORM PREDICTION CENTER NORMAN OK 0807 PM CDT WED OCT 17 2012 AREAS AFFECTED...PARTS OF WRN AND MIDDLE TN CONCERNING...SEVERE POTENTIAL...WATCH LIKELY VALID 180107Z - 180200Z PROBABILITY OF WATCH ISSUANCE...80 PERCENT SUMMARY...STORMS NOW CROSSING THE MS VALLEY WILL LIKELY POSE DAMAGING WIND POTENTIAL INTO THE TN VALLEY REGION. NEW WW WILL BE NEEDED SHORTLY. DISCUSSION...ONGOING STORMS ARE CROSSING THE MS RIVER ATTM...WITH EMBEDDED ROTATING CELLS ALONG THE LINE OF CONVECTION POSING TORNADO RISK ATTM. AS THE LINE OF STORMS MOVES INTO AN ENVIRONMENT FEATURING AN INCREASINGLY STABLE BOUNDARY LAYER...TORNADO THREAT WILL DIMINISH WITH ERN EXTENT. HOWEVER...GIVEN STRONG FORCING -- INDICATED BY PRONOUNCED PRESSURE RISE/FALL COUPLET ALONG AND JUST E OF THE MS VALLEY -- EXPECT ORGANIZED STORMS TO CONTINUE INTO THIS MORE STABLE AIRMASS...POSING A THREAT FOR LOCALLY DAMAGING WINDS OVER THE NEXT FEW HOURS. ..GOSS/CORFIDI.. 10/18/2012 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...LMK...OHX...HUN...PAH...MEG... LAT...LON 34818770 34918906 35298941 36668855 36718695 34818770
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 17, 7:35 PM CDT | Mesoscale Discussion | SPC | Ballard, Carlisle, Fulton, Hickman | 85 min |
| Oct 17, 7:47 PM CDT | Severe Thunderstorm Watch | SPC | Caldwell, Calloway, Christian, Crittenden, Daviess, Henderson and 10 more | 75 min |
| Oct 18, 2:07 PM CDT | Mesoscale Discussion | SPC | Pike | 83 min |
| Oct 17, 7:01 PM CDT | Tornado Watch | SPC | Adams, Attala, Bolivar, Carroll, Choctaw, Claiborne and 35 more | 8 hr |
| Oct 17, 8:23 PM CDT | Tornado Watch | SPC | Alcorn, Benton, Calhoun, Chickasaw, Itawamba, Lafayette and 8 more | 5 hr |
| Oct 17, 9:28 PM CDT | Mesoscale Discussion | SPC | Alcorn, Attala, Benton, Bolivar, Calhoun, Carroll and 42 more | 92 min |
| Oct 17, 11:49 PM CDT | Mesoscale Discussion | SPC | Attala, Calhoun, Carroll, Chickasaw, Choctaw, Claiborne and 31 more | 86 min |
| Oct 18, 1:09 AM CDT | Mesoscale Discussion | SPC | George, Greene, Perry, Stone | 96 min |
| Oct 18, 2:40 AM CDT | Mesoscale Discussion | SPC | Amite, Clarke, Covington, Forrest, George, Greene and 12 more | 65 min |
| Oct 17, 8:43 PM CDT | Severe Thunderstorm Watch | SPC | Benton, Carroll, Cheatham, Chester, Decatur, Dickson and 14 more | 4 hr |
Nearby
Mesoscale Discussions in Tennessee, 2012Mesoscale Discussions in Kentucky, 2012Mesoscale Discussions in Mississippi, 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.