Alert archive / Kentucky / Mesoscale Discussions in 2012

Mesoscale Discussion 256

March 15, 20127 states

The Storm Prediction Center issued this mesoscale discussion at Mar 15, 2012, 1:08 PM CDT for 7 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Mar 15, 2012, 1:08 PM CDT (18:08 UTC)
Expired
Mar 15, 2012, 3:15 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 217 counties

Alexander County, IL, Clay County, IL, Crawford County, IL, Edwards County, IL, Franklin County, IL, Gallatin County, IL, Hamilton County, IL, Hardin County, IL, Jasper County, IL, Johnson County, IL, Lawrence County, IL, Massac County, IL, Pope County, IL, Pulaski County, IL, Richland County, IL, Saline County, IL, Union County, IL, Wabash County, IL, Wayne County, IL, White County, IL, Williamson County, IL, Brown County, IN, Clark County, IN, Crawford County, IN, Daviess County, IN, Dubois County, IN, Floyd County, IN, Gibson County, IN, Greene County, IN, Harrison County, IN, Jackson County, IN, Jefferson County, IN, Jennings County, IN, Knox County, IN, Lawrence County, IN, Martin County, IN, Monroe County, IN, Orange County, IN, Perry County, IN, Pike County, IN, Posey County, IN, Scott County, IN, Spencer County, IN, Sullivan County, IN, Vanderburgh County, IN, Warrick County, IN, Washington County, IN, Adair County, KY, Allen County, KY, Anderson County, KY, Ballard County, KY, Barren County, KY, Bell County, KY, Boyle County, KY, Breathitt County, KY, Breckinridge County, KY, Bullitt County, KY, Butler County, KY, Caldwell County, KY, Calloway County, KY, Carlisle County, KY, Carroll County, KY, Casey County, KY, Christian County, KY, Clark County, KY, Clay County, KY, Clinton County, KY, Crittenden County, KY, Cumberland County, KY, Daviess County, KY, Edmonson County, KY, Estill County, KY, Fayette County, KY, Floyd County, KY, Franklin County, KY, Fulton County, KY, Garrard County, KY, Graves County, KY, Grayson County, KY, Green County, KY, Hancock County, KY, Hardin County, KY, Harlan County, KY, Hart County, KY, Henderson County, KY, Henry County, KY, Hickman County, KY, Hopkins County, KY, Jackson County, KY, Jefferson County, KY, Jessamine County, KY, Knott County, KY, Knox County, KY, Larue County, KY, Laurel County, KY, Lee County, KY, Leslie County, KY, Letcher County, KY, Lincoln County, KY, Livingston County, KY, Logan County, KY, Lyon County, KY, Madison County, KY, Magoffin County, KY, Marion County, KY, Marshall County, KY, McCracken County, KY, McCreary County, KY, McLean County, KY, Meade County, KY, Menifee County, KY, Mercer County, KY, Metcalfe County, KY, Monroe County, KY, Montgomery County, KY, Muhlenberg County, KY, Nelson County, KY, Ohio County, KY, Oldham County, KY, Owen County, KY, Owsley County, KY, Perry County, KY, Pike County, KY, Powell County, KY, Pulaski 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, Trimble County, KY, Union County, KY, Warren County, KY, Washington County, KY, Wayne County, KY, Webster County, KY, Whitley County, KY, Wolfe County, KY, Woodford County, KY, Mississippi County, MO, Scott County, MO, Madison County, NC, Anderson County, TN, Bedford County, TN, Benton County, TN, Bledsoe County, TN, Blount County, TN, Campbell County, TN, Cannon County, TN, Carter County, TN, Cheatham County, TN, Claiborne County, TN, Clay County, TN, Cocke County, TN, Coffee County, TN, Cumberland County, TN, Davidson County, TN, DeKalb County, TN, Dickson County, TN, Fentress County, TN, Grainger County, TN, Greene County, TN, Hamblen County, TN, Hancock County, TN, Hawkins County, TN, Henry County, TN, Hickman County, TN, Houston County, TN, Humphreys County, TN, Jackson County, TN, Jefferson County, TN, Knox County, TN, Loudon County, TN, Macon County, TN, Maury County, TN, McMinn County, TN, Meigs County, TN, Monroe County, TN, Montgomery County, TN, Morgan County, TN, Obion County, TN, Overton County, TN, Pickett County, TN, Putnam County, TN, Rhea County, TN, Roane County, TN, Robertson County, TN, Rutherford County, TN, Scott County, TN, Sevier County, TN, Smith County, TN, Stewart County, TN, Sullivan County, TN, Sumner County, TN, Trousdale County, TN, Unicoi County, TN, Union County, TN, Van Buren County, TN, Warren County, TN, Washington County, TN, Weakley County, TN, White County, TN, Williamson County, TN, Wilson County, TN, Buchanan County, VA, City of Bristol, VA, City of Norton, VA, Dickenson County, VA, Lee County, VA, Russell County, VA, Scott County, VA, Washington County, VA, Wise County, VA

The radar

The Louisville radar (KLVX), 92 km from the middle of the area, began a volume at 18:10 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, 6.1 hours before the alert went out and 162 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 2012-03-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1726 joules per kilogram.LCLLFCEL10008507005003002001001 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 2012-03-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 90 square meters per square second.1939Sfc1 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
1726 J/kg
Mixed-layer CIN
-46 J/kg
Mixed-layer LCL
820 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
90 m²/s²
0-3 km storm-relative helicity
108 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.

549 
ACUS11 KWNS 151809
SWOMCD
SPC MCD 151808
VAZ000-WVZ000-TNZ000-KYZ000-NCZ000-INZ000-ILZ000-MOZ000-152015-

MESOSCALE DISCUSSION 0256
NWS STORM PREDICTION CENTER NORMAN OK
0108 PM CDT THU MAR 15 2012

AREAS AFFECTED...TN/LOWER OH VALLEYS TOWARDS THE SRN APPALACHIANS

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 151808Z - 152015Z

PULSE TSTMS WITH A FEW MULTICELL CLUSTERS WILL BECOME INCREASINGLY
PREVALENT THIS AFTERNOON. GIVEN A STEEP LAPSE RATE BUT WEAKLY
SHEARED ENVIRONMENT...RISKS WILL PRIMARILY BE SPORADIC SEVERE HAIL
WITH LOCALLY GUSTY WINDS. THE DISORGANIZED NATURE OF THE TSTMS
SHOULD PRECLUDE THE NEED FOR A WW ISSUANCE.

CONVECTION HAS INCREASED IN BETWEEN TWO SLOW-MOVING TSTM CLUSTERS
THAT HAD PERSISTED FOR THE PAST SEVERAL HOURS ACROSS THE MID-MS AND
PARTS OF THE CNTRL OH VALLEY. VWP/UPSTREAM PROFILER DATA INDICATE
WEAK DEEP-LAYER FLOW WHICH HAS LIMITED EFFECTIVE SHEAR LARGELY TO
AROUND 10-20 KT. THIS SHOULD RESULT IN RATHER DISORGANIZED
STRUCTURES CONSISTING OF PULSE TO OCCASIONAL MULTICELL CONVECTIVE
MODES. WITH 700-500 MB LAPSE RATES OF 7.5 TO 8.0 DEG C/KM SAMPLED IN
12Z AREA RAOBS...MLCAPE OF 1500 TO 2500 J/KG WILL BE FAVORABLE FOR
SPORADIC SEVERE HAIL PRODUCTION UNTIL THE AIR MASS IS OVERTURNED.

..GRAMS.. 03/15/2012

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

ATTN...WFO...RNK...RLX...GSP...MRX...JKL...ILN...LMK...OHX...
IND...PAH...ILX...MEG...LSX...

LAT...LON   37058966 38918855 39268717 39168560 38638481 38148416
            37808312 37538204 37128162 37108164 36498182 35728285
            35368456 35538720 36128868 36388932 37058966

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 15, 5:02 PM CDTMesoscale DiscussionSPCBrown, Cass, DeWitt, Ford, Fulton, Greene and 19 more2 hr
Mar 15, 2:06 PM CDTSevere Thunderstorm WatchSPCClark, Crawford, Dubois, Floyd, Harrison, Jefferson and 4 more6 hr
Mar 15, 3:44 PM CDTMesoscale DiscussionSPCBartholomew, Clark, Dearborn, Decatur, Fayette, Floyd and 17 more61 min
Mar 15, 4:28 PM CDTSevere Thunderstorm WatchSPCDearborn, Fayette, Franklin, Ohio, Ripley, Switzerland and 2 more3 hr
Mar 15, 6:23 PM CDTMesoscale DiscussionSPCBath, Bell, Bourbon, Bracken, Breathitt, Campbell and 36 more97 min
Mar 15, 2:47 PM CDTMesoscale DiscussionSPCButler, Carter, Crawford, Dent, Douglas, Franklin and 22 more118 min

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.