Alert archive / Tennessee / Mesoscale Discussions in 2012

Mesoscale Discussion 2059

October 14, 20124 counties in Kentucky; 4 counties in Mississippi; 12 counties in Tennessee

The Storm Prediction Center issued this mesoscale discussion at Oct 14, 2012, 7:22 AM CDT for 4 counties in Kentucky; 4 counties in Mississippi; 12 counties in Tennessee. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued
Oct 14, 2012, 7:22 AM CDT (12:22 UTC)
Expired
Oct 14, 2012, 8:45 AM CDT
In force
83 min
Issued by
the Storm Prediction Center
Chance of a watch
20%

Counties Caldwell County, KY, Christian County, KY, Lyon County, KY, Trigg County, KY, Alcorn County, MS, Prentiss County, MS, Tippah County, MS, Union County, MS, Benton County, TN, Chester County, TN, Decatur County, TN, Dickson County, TN, Hardin County, TN, Henderson County, TN, Houston County, TN, Humphreys County, TN, McNairy County, TN, Montgomery County, TN, Perry County, TN, Stewart County, TN

The radar

The Memphis radar (KNQA), 144 km from the middle of the area, began a volume at 12:21 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, 0.4 hours before the alert went out and 164 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 2012-10-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2012-10-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 437 square meters per square second.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
761 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
437 m²/s²
0-3 km storm-relative helicity
506 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

743 
ACUS11 KWNS 141222
SWOMCD
SPC MCD 141222 
TNZ000-KYZ000-ALZ000-MSZ000-141345-

MESOSCALE DISCUSSION 2059
NWS STORM PREDICTION CENTER NORMAN OK
0722 AM CDT SUN OCT 14 2012

AREAS AFFECTED...WRN KY THROUGH WRN MIDDLE TN INTO NERN MS

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 141222Z - 141345Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...LINE OF SHALLOW CONVECTION WILL CONTINUE THROUGH WRN
KY...WRN MIDDLE TN AND NERN MS EARLY THIS MORNING. SOME OF THE
ACTIVITY APPEARS TO HAVE UNDERGONE A SLIGHT BUT LIKELY TEMPORARY
INCREASE IN INTENSITY...AND A FEW ORGANIZED STRUCTURES HAVE RECENTLY
BEEN OBSERVED. AN ISOLATED STRONG TO DAMAGING WIND GUST OR TWO
CANNOT BE RULED OUT...BUT A WW IS NOT ANTICIPATED AT THIS TIME.

DISCUSSION...PRE-FRONTAL BAND OF CONVECTION DEVELOPING ALONG THE
WARM CONVEYOR BELT CONTINUES FROM NRN MS INTO WRN MIDDLE TN AND SWRN
KY. ACTIVITY IS SHALLOW WITH NO LIGHTNING INDICATED AND IS
DEVELOPING WITHIN AN ENVIRONMENT CHARACTERIZED BY MEAGER
INSTABILITY. RAPID REFRESH PFCS MODIFIED FOR CURRENT CONDITIONS
INDICATE MUCAPE AOB 200 J/KG. THE CONVECTION IS EMBEDDED WITHIN A
STRONG KINEMATIC ENVIRONMENT WITH 50+ KT LLJ SUPPORTING LARGE
HODOGRAPHS. LEWP STRUCTURES AND ROTATION HAVE BEEN OBSERVED IN LINE
SEGMENT MOVING THROUGH SWRN KY AND ISOLATED STRONG WIND GUSTS CANNOT
BE RULED OUT. INSTABILITY IS PROGRESSIVELY WEAKER WITH ERN EXTENT
TOWARD MIDDLE TN AND CNTRL KY WHERE SELY TRAJECTORIES FROM HIGH
PRESSURE CENTERED OFF THE U.S. SEABOARD HAVE MAINTAINED SFC
DEWPOINTS IN THE UPPER 50S. NASHVILLE 12Z RAOB INDICATED VIRTUALLY
NO CAPE AND FURTHER STRENGTHENING APPEARS UNLIKELY AT THIS TIME.

..DIAL/MEAD.. 10/14/2012

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

ATTN...WFO...OHX...HUN...PAH...MEG...

LAT...LON   35248895 36128830 37088821 37348736 36328724 34358863
            34488934 35248895

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.