Alert archive / Kentucky / Mesoscale Discussions in 2012
Mesoscale Discussion 2170
The Storm Prediction Center issued this mesoscale discussion at Dec 17, 2012, 12:03 PM EST for Floyd County, Harrison County, Perry County, Indiana; 68 counties in Kentucky; 25 counties in Tennessee. It was in force for 117 min.
The area
The outline as issued.
The facts
- Issued
- Dec 17, 2012, 12:03 PM EST (17:03 UTC)
- Expired
- Dec 17, 2012, 2:00 PM EST
- In force
- 117 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 95%
All 96 counties
Floyd County, IN, Harrison County, IN, Perry County, IN, Adair County, KY, Allen County, KY, Anderson County, KY, Barren County, KY, Bourbon County, KY, Boyle County, KY, Breckinridge County, KY, Bullitt County, KY, Butler County, KY, Caldwell County, KY, Calloway County, KY, Carroll County, KY, Casey County, KY, Christian County, KY, Clark County, KY, Clinton County, KY, Cumberland County, KY, Daviess County, KY, Edmonson County, KY, Fayette County, KY, Franklin County, KY, Garrard County, KY, Grant County, KY, Grayson County, KY, Green County, KY, Hancock County, KY, Hardin County, KY, Harrison County, KY, Hart County, KY, Henry County, KY, Hopkins County, KY, Jefferson County, KY, Jessamine County, KY, Larue County, KY, Lincoln County, KY, Logan County, KY, Lyon County, KY, Madison County, KY, Marion County, KY, McLean County, KY, Meade County, KY, Mercer County, KY, Metcalfe County, KY, Monroe County, KY, Montgomery County, KY, Muhlenberg County, KY, Nelson County, KY, Nicholas County, KY, Ohio County, KY, Oldham County, KY, Owen County, KY, Pendleton County, KY, Pulaski County, KY, Robertson County, KY, Rockcastle County, KY, Russell County, KY, Scott County, KY, Shelby County, KY, Simpson County, KY, Spencer County, KY, Taylor County, KY, Todd County, KY, Trigg County, KY, Warren County, KY, Washington County, KY, Wayne County, KY, Webster County, KY, Woodford County, KY, Benton County, TN, Cannon County, TN, Cheatham County, TN, Clay County, TN, Davidson County, TN, DeKalb County, TN, Dickson County, TN, Hickman County, TN, Houston County, TN, Humphreys County, TN, Jackson County, TN, Macon County, TN, Maury County, TN, Montgomery County, TN, Overton County, TN, Pickett County, TN, Putnam County, TN, Robertson County, TN, Rutherford County, TN, Smith County, TN, Stewart County, TN, Sumner County, TN, Trousdale County, TN, Williamson County, TN, Wilson County, TN
The radar
The Louisville radar (KLVX), 60 km from the middle of the area, began a volume at 17:06 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, 5.1 hours before the alert went out and 158 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
- 100 J/kg
- Mixed-layer CIN
- -5 J/kg
- Mixed-layer LCL
- 447 m above ground
- 0-6 km bulk shear
- 78 kt
- 0-1 km storm-relative helicity
- 91 m²/s²
- 0-3 km storm-relative helicity
- 185 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
265
ACUS11 KWNS 171703
SWOMCD
SPC MCD 171703
KYZ000-TNZ000-INZ000-171900-
MESOSCALE DISCUSSION 2170
NWS STORM PREDICTION CENTER NORMAN OK
1103 AM CST MON DEC 17 2012
AREAS AFFECTED...CNTRL/WRN KY...PARTS OF WRN/MIDDLE TN...FAR SRN IND
CONCERNING...SEVERE POTENTIAL...SEVERE THUNDERSTORM WATCH LIKELY
VALID 171703Z - 171900Z
PROBABILITY OF WATCH ISSUANCE...95 PERCENT
SUMMARY...SVR THUNDERSTORMS...INCLUDING SUPERCELLS...ARE EXPECTED TO
DEVELOP ACROSS PARTS OF THE LOWER OH AND TN VALLEY BETWEEN 18Z AND
20Z. SVR HAIL...POTENTIALLY TO GOLFBALL SIZE...ALONG WITH SVR WIND
GUSTS WILL BE POSSIBLE. A SEVERE THUNDERSTORM WATCH WILL LIKELY BE
ISSUED EARLY THIS AFTERNOON.
DISCUSSION...WATER VAPOR LOOPS REVEAL A MID-LEVEL DRY SLOT IN
ADVANCE OF A MID-LEVEL VORT MAX CURRENTLY ENTERING WRN MO. THE VORT
MAX WILL CONTINUE TO TRACK ENEWD IN TANDEM WITH A LEADING ASCENT
MAX -- EVIDENT OVER THE INTERSECTION OF THE OH AND MS RIVERS PER
WATER VAPOR IMAGERY. THIS DRY SLOT IS ALLOWING TEMPS TO CLIMB INTO
THE UPPER 50S TO LOWER 60S AMIDST A CORRIDOR OF PARTIAL SUNSHINE
SOUTH OF A STATIONARY FRONT THAT LIES APPROXIMATELY ALONG THE OHIO
RIVER. MODIFIED FORECAST SOUNDINGS SUGGEST THAT THESE TEMPS COMBINED
WITH ANOMALOUSLY HIGH DEWPOINTS IN THE 50S ARE CONTRIBUTING TO
MLCAPE VALUES OF 400-800 J/KG. STORMS WILL LIKELY DEVELOP BETWEEN
18Z AND 20Z ALONG AN EWD-MOVING CONFLUENCE AXIS CURRENTLY EXTENDING
FROM OWB TO SW OF HOP. DESPITE THE MARGINAL INSTABILITY...LARGE
NORMALIZED CAPE VALUES -- PARTLY OWING TO THE INFLUX OF 7-8 C/KM
MID-LEVEL LAPSE RATES -- WILL YIELD INTENSE UPDRAFT ACCELERATIONS
GIVEN 30-45 KT OF DEEP SHEAR. NEARLY UNIDIRECTIONAL WSWLY FLOW
THROUGH THE CAPE LAYER FEATURING LONG HODOGRAPHS WILL SUPPORT
SUPERCELL STRUCTURES AND QUASI-LINEAR SEGMENTS WITH HAIL POTENTIALLY
REACHING GOLFBALL SIZE...ALONG WITH STRONG TO MARGINALLY SVR WIND
GUSTS.
..COHEN/CORFIDI.. 12/17/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...JKL...ILN...LMK...OHX...PAH...MEG...
LAT...LON 37488407 35838562 35518708 35988824 36768833 37228813
37788747 38178650 38728500 38848442 38628403 38248382
37488407SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 17, 12:26 PM EST | Severe Thunderstorm Watch | SPC | Clark, Crawford, Dubois, Floyd, Harrison, Jefferson and 7 more | 6 hr |
| Dec 17, 1:58 PM EST | Mesoscale Discussion | SPC | Clark, Crawford, Floyd, Harrison, Jefferson, Perry and 2 more | 92 min |
| Dec 17, 4:42 PM EST | Mesoscale Discussion | SPC | Adair, Allen, Anderson, Barren, Bath, Bourbon and 49 more | 93 min |
| Dec 17, 2:24 PM EST | Mesoscale Discussion | SPC | Bedford, Chester, Coffee, Decatur, Giles, Grundy and 12 more | 2 hr |
Nearby
Mesoscale Discussions in Kentucky, 2012Mesoscale Discussions in Tennessee, 2012Mesoscale Discussions in Indiana, 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.