Alert archive / Kentucky / Mesoscale Discussions in 2017

Mesoscale Discussion 779

May 19, 201732 counties in Indiana; 37 counties in Kentucky; 26 counties in Ohio

The Storm Prediction Center issued this mesoscale discussion at May 19, 2017, 1:38 PM EDT for 32 counties in Indiana; 37 counties in Kentucky; 26 counties in Ohio. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: May 19, 2017, 1:38 PM EDT (17:38 UTC)
Expired: May 19, 2017, 3:45 PM EDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 60%

All 95 counties

Bartholomew County, IN, Brown County, IN, Clark County, IN, Crawford County, IN, Dearborn County, IN, Decatur County, IN, Fayette County, IN, Floyd County, IN, Franklin County, IN, Hancock County, IN, Harrison County, IN, Henry County, IN, Jackson County, IN, Jefferson County, IN, Jennings County, IN, Johnson County, IN, Lawrence County, IN, Marion County, IN, Martin County, IN, Monroe County, IN, Morgan County, IN, Ohio County, IN, Orange County, IN, Owen County, IN, Ripley County, IN, Rush County, IN, Scott County, IN, Shelby County, IN, Switzerland County, IN, Union County, IN, Washington County, IN, Wayne County, IN, Anderson County, KY, Bath County, KY, Boone County, KY, Bourbon County, KY, Boyd County, KY, Bracken County, KY, Bullitt County, KY, Campbell County, KY, Carroll County, KY, Carter County, KY, Clark County, KY, Elliott County, KY, Fayette County, KY, Fleming County, KY, Franklin County, KY, Gallatin County, KY, Grant County, KY, Greenup County, KY, Harrison County, KY, Henry County, KY, Jefferson County, KY, Kenton County, KY, Lewis County, KY, Mason County, KY, Meade County, KY, Montgomery County, KY, Nicholas County, KY, Oldham County, KY, Owen County, KY, Pendleton County, KY, Robertson County, KY, Rowan County, KY, Scott County, KY, Shelby County, KY, Spencer County, KY, Trimble County, KY, Woodford County, KY, Adams County, OH, Brown County, OH, Butler County, OH, Clark County, OH, Clermont County, OH, Clinton County, OH, Fairfield County, OH, Fayette County, OH, Franklin County, OH, Greene County, OH, Hamilton County, OH, Highland County, OH, Hocking County, OH, Jackson County, OH, Lawrence County, OH, Madison County, OH, Miami County, OH, Montgomery County, OH, Perry County, OH, Pickaway County, OH, Pike County, OH, Preble County, OH, Ross County, OH, Scioto County, OH, Vinton County, OH, Warren County, OH

The radar

The Cincinnati radar (KILN), 67 km from the middle of the area, began a volume at 17:38 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.

Severe Thunderstorm Watch 247May 19, 3:10 PM EDT

The nearest sounding before it

Cncnati-Daytn, OH (KILN), launched 12:00Z, 5.6 hours before the alert went out and 69 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 387 J/kg
Mixed-layer CIN: -64 J/kg
Mixed-layer LCL: 1118 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 51 m²/s²
0-3 km storm-relative helicity: 70 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.6

Open this sounding in Storm Lab

The text

As transmitted.

024 
ACUS11 KWNS 191739
SWOMCD
SPC MCD 191738 
OHZ000-KYZ000-INZ000-191945-

Mesoscale Discussion 0779
NWS Storm Prediction Center Norman OK
1238 PM CDT Fri May 19 2017

Areas affected...Portions of southern IN...northern KY...and
southern OH

Concerning...Severe potential...Watch possible 

Valid 191738Z - 191945Z

Probability of Watch Issuance...60 percent

SUMMARY...An increasing damaging wind threat with thunderstorms
intensifying across southern IN may warrant watch issuance in the
next several hours. Isolated large hail may also occur.

DISCUSSION...A nearly stationary front extends across central IN/OH
this afternoon. Diurnal heating along and south of the front has
encouraged surface temperatures to warm into the upper 70s to lower
80s, and MLCAPE has increased into the 1000-1500 J/kg range in the
warm sector. A moist low-level airmass was sampled by the 12Z ILN
sounding, although mid-level lapse rates were modest around 6.5 C/km
in the 700-500 mb layer. Semi-discrete convection has recently
strengthened across southern IN as outflow associated with prior
overnight convection across MO/IL has encountered the unstable
airmass south of the front. With 0-6 km shear vectors oriented
nearly perpendicular to the strengthening convection, upscale growth
into one or more bowing line segments seems likely over the next
several hours. The damaging wind threat associated with this
activity should likewise increase this afternoon with 30-40 kt of
effective bulk shear present to support thunderstorm organization,
and at least some damaging wind threat may continue into the early
evening hours across parts of southern OH and northern KY per 14Z
experimental HRRR. Isolated large hail may also occur for the next
several hours if storms remain semi-discrete. Watch issuance is
possible pending signs of greater convective organization.

..Gleason/Kerr.. 05/19/2017

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...RLX...JKL...ILN...LMK...IND...

LAT...LON   37988298 37868597 37988647 38848695 39168697 39718658
            40138512 40128308 39988237 39548212 38948222 38458257
            37988298

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 19, 3:13 PM EDT	Severe Thunderstorm Watch	SPC	Dearborn, Fayette, Franklin, Ohio, Ripley, Switzerland and 2 more	6 hr
May 19, 5:50 PM EDT	Mesoscale Discussion	SPC	Bracken, Campbell, Grant, Mason, Pendleton	55 min
May 19, 6:03 PM EDT	Mesoscale Discussion	SPC	Carlisle, Fulton, Hickman	117 min

Nearby

Mesoscale Discussions in Kentucky, 2017 Mesoscale Discussions in Indiana, 2017 Mesoscale Discussions in Ohio, 2017 Every mesoscale discussion in 2017

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.