Alert archive / Indiana / Mesoscale Discussions in 2021

Mesoscale Discussion 1298

July 16, 20214 states

The Storm Prediction Center issued this mesoscale discussion at Jul 16, 2021, 12:10 PM CDT for 4 states. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued: Jul 16, 2021, 12:10 PM CDT (17:10 UTC)
Expired: Jul 16, 2021, 4:15 PM CDT
In force: 4 hr
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch unlikely
Chance of a watch: 20%

All 74 counties

Edwards County, IL, Wabash County, IL, Clark County, IN, Crawford County, IN, Daviess County, IN, Dearborn County, IN, Decatur County, IN, Dubois County, IN, Floyd County, IN, Franklin County, IN, Gibson County, IN, Harrison County, IN, Jackson County, IN, Jefferson County, IN, Jennings County, IN, Knox County, IN, Lawrence County, IN, Martin County, IN, Ohio County, IN, Orange County, IN, Perry County, IN, Pike County, IN, Posey County, IN, Ripley County, IN, Scott County, IN, Spencer County, IN, Switzerland County, IN, Vanderburgh County, IN, Warrick County, IN, Washington County, IN, Boone County, KY, Bracken County, KY, Campbell County, KY, Carroll County, KY, Fleming County, KY, Franklin County, KY, Gallatin County, KY, Grant County, KY, Hancock County, KY, Harrison County, KY, Henderson County, KY, Henry County, KY, Jefferson County, KY, Kenton County, KY, Mason County, KY, Meade County, KY, Nicholas County, KY, Oldham County, KY, Owen County, KY, Pendleton County, KY, Robertson County, KY, Scott County, KY, Shelby County, KY, Trimble 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, Madison County, OH, Montgomery County, OH, Pickaway County, OH, Pike County, OH, Preble County, OH, Ross County, OH, Scioto County, OH, Warren County, OH

The radar

The Cincinnati radar (KILN), 81 km from the middle of the area, began a volume at 17:11 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, 5.2 hours before the alert went out and 84 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: 291 J/kg
Mixed-layer CIN: -68 J/kg
Mixed-layer LCL: 941 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 99 m²/s²
0-3 km storm-relative helicity: 92 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

Open this sounding in Storm Lab

The text

As transmitted.

782 
ACUS11 KWNS 161711
SWOMCD
SPC MCD 161710 
OHZ000-KYZ000-INZ000-ILZ000-162115-

Mesoscale Discussion 1298
NWS Storm Prediction Center Norman OK
1210 PM CDT Fri Jul 16 2021

Areas affected...southern Indiana and Ohio...northern Kentucky

Concerning...Severe potential...Watch unlikely 

Valid 161710Z - 162115Z

Probability of Watch Issuance...20 percent

SUMMARY...A gradual increase of storms is expected through the
afternoon, and a few could produce locally strong wind gusts across
southern Illinois, Indiana, Ohio and northern Kentucky.

DISCUSSION...A belt of 30-40 kt midlevel southwesterlies currently
exists across the region, with an instability gradient situated
across southern IL and IN and into central OH. Visible imagery shows
good heating across much of the region, and southwesterly surface
winds will maintain higher theta-e across the OH Valley this
afternoon.

Isolated storms are currently developing over southern IL ahead of
an MCV, and over southeast IN where low-level warm/moist advection
is maximized. Continued heating and sufficient surface convergence
should support more storm development over the next several hours.
Aforementioned midlevel wind speeds may allow for a few fast moving,
forward propagating storms capable of strong outflow winds, mainly
along the instability gradient. Poor lapse rates aloft as well as
the weak shear should limit severe coverage and organization, with a
watch unlikely as a result.

..Jewell/Dial.. 07/16/2021

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

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

LAT...LON   38358366 37658778 37888811 38518813 39368538 39958425
            40158325 40018266 39628254 39208273 38878291 38358366

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.