Alert archive / Indiana / Mesoscale Discussions in 2021

Mesoscale Discussion 1199

July 8, 202144 counties in Indiana; 18 counties in Kentucky; Butler County, Hamilton County, Ohio

The Storm Prediction Center issued this mesoscale discussion at Jul 8, 2021, 1:51 PM EDT for 44 counties in Indiana; 18 counties in Kentucky; Butler County, Hamilton County, Ohio. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued: Jul 8, 2021, 1:51 PM EDT (17:51 UTC)
Expired: Jul 8, 2021, 3:15 PM EDT
In force: 84 min
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch possible
Chance of a watch: 40%

All 64 counties

Bartholomew County, IN, Brown County, IN, Clark County, IN, Clay County, IN, Crawford County, IN, Daviess County, IN, Dearborn County, IN, Decatur County, IN, Dubois County, IN, Fayette County, IN, Floyd County, IN, Franklin County, IN, Gibson County, IN, Greene County, IN, Hancock County, IN, Harrison County, IN, Hendricks County, IN, Jackson County, IN, Jefferson County, IN, Jennings County, IN, Johnson County, IN, Knox 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, Perry County, IN, Pike County, IN, Putnam County, IN, Ripley County, IN, Rush County, IN, Scott County, IN, Shelby County, IN, Spencer County, IN, Sullivan County, IN, Switzerland County, IN, Union County, IN, Vigo County, IN, Warrick County, IN, Washington County, IN, Boone County, KY, Breckinridge County, KY, Bullitt County, KY, Campbell County, KY, Carroll County, KY, Gallatin County, KY, Grant County, KY, Hancock County, KY, Hardin County, KY, Henry County, KY, Jefferson County, KY, Kenton County, KY, Meade County, KY, Oldham County, KY, Owen County, KY, Shelby County, KY, Spencer County, KY, Trimble County, KY, Butler County, OH, Hamilton County, OH

The radar

The Indianapolis radar (KIND), 90 km from the middle of the area, began a volume at 17:50 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

Cncnati-Daytn, OH (KILN), launched 12:00Z, 5.9 hours before the alert went out and 186 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: 187 J/kg
Mixed-layer CIN: -29 J/kg
Mixed-layer LCL: 768 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 36 m²/s²
0-3 km storm-relative helicity: 34 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

270 
ACUS11 KWNS 081751
SWOMCD
SPC MCD 081751 
OHZ000-KYZ000-INZ000-ILZ000-081915-

Mesoscale Discussion 1199
NWS Storm Prediction Center Norman OK
1251 PM CDT Thu Jul 08 2021

Areas affected...portions of the Ohio River Valley and central
Indiana.

Concerning...Severe potential...Watch possible 

Valid 081751Z - 081915Z

Probability of Watch Issuance...40 percent

SUMMARY...Several clusters of strong thunderstorms will pose a risk
mainly for damaging wind gusts as they track southeastward this
afternoon. Convective trends are being monitored for a possible
weather watch.

DISCUSSION...Over the last hour, regional radar mosaics and visible
imagery have shown thunderstorms increasing in intensity and
coverage across portions of south-central Indiana and eastern
Illinois. Located along a cold front front beneath the western
portions of a mid-level trough, these storms are ongoing in a
moderately unstable/sheared environment. Obs and SPC mesoanalysis
indicate dewpoints in the 70s F are contributing to around 1500-2000
J/kg of MLCAPE despite modest mid-level lapse rates. Mid-level flow
behind the trough is not overly strong, but is supporting 25-30 kts
of effective shear. This should act to organize storms into
multicell clusters and short line segments capable of damaging wind
gusts. 

As additional storm development takes place this afternoon, some
upscale growth into a more organized linear segment appears
possible. As such, an additional risk for damaging winds may develop
near and immediately south of the Ohio River across portions of
northern Kentucky and southwestern Ohio. Uncertainty on the nature
of the severe threat remains, but convective trends suggest a watch
could be needed this afternoon.

..Lyons/Guyer.. 07/08/2021

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

ATTN...WFO...ILN...LMK...IND...PAH...ILX...

LAT...LON   39718473 39608450 39278426 39118424 38728457 38498471
            37998525 37628604 37578675 37818717 38268758 38658761
            39058762 39438751 39788715 39908655 39888561 39798508
            39718473

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 8, 1:31 PM EDT	Mesoscale Discussion	SPC	Ashland, Ashtabula, Carroll, Columbiana, Cuyahoga, Geauga and 11 more	2 hr

Nearby

Mesoscale Discussions in Indiana, 2021 Mesoscale Discussions in Kentucky, 2021 Mesoscale Discussions in Ohio, 2021 Every mesoscale discussion in 2021

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.