Alert archive / Indiana / Mesoscale Discussions in 2021

Mesoscale Discussion 1124

June 29, 20214 states

The Storm Prediction Center issued this mesoscale discussion at Jun 29, 2021, 11:54 AM CDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jun 29, 2021, 11:54 AM CDT (16:54 UTC)
Expired: Jun 29, 2021, 2:00 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch unlikely
Chance of a watch: 20%

All 82 counties

Champaign County, IL, DeWitt County, IL, Douglas County, IL, Edgar County, IL, Ford County, IL, Iroquois County, IL, Kankakee County, IL, Macon County, IL, Piatt County, IL, Vermilion County, IL, Adams County, IN, Allen County, IN, Benton County, IN, Blackford County, IN, Boone County, IN, Carroll County, IN, Cass County, IN, Clinton County, IN, DeKalb County, IN, Elkhart County, IN, Fountain County, IN, Fulton County, IN, Grant County, IN, Hamilton County, IN, Howard County, IN, Huntington County, IN, Jasper County, IN, Kosciusko County, IN, LaGrange County, IN, Lake County, IN, LaPorte County, IN, Madison County, IN, Marshall County, IN, Miami County, IN, Montgomery County, IN, Newton County, IN, Noble County, IN, Parke County, IN, Porter County, IN, Pulaski County, IN, Saint Joseph County, IN, Starke County, IN, Steuben County, IN, Tippecanoe County, IN, Tipton County, IN, Vermillion County, IN, Wabash County, IN, Warren County, IN, Wells County, IN, White County, IN, Whitley County, IN, Barry County, MI, Berrien County, MI, Branch County, MI, Calhoun County, MI, Cass County, MI, Eaton County, MI, Genesee County, MI, Hillsdale County, MI, Ingham County, MI, Jackson County, MI, Kalamazoo County, MI, Lapeer County, MI, Lenawee County, MI, Livingston County, MI, Macomb County, MI, Monroe County, MI, Oakland County, MI, Saint Clair County, MI, Saint Joseph County, MI, Shiawassee County, MI, Washtenaw County, MI, Wayne County, MI, Defiance County, OH, Fulton County, OH, Henry County, OH, Lucas County, OH, Paulding County, OH, Putnam County, OH, Van Wert County, OH, Williams County, OH, Wood County, OH

The radar

The Northern Indiana radar (KIWX), 11 km from the middle of the area, began a volume at 16:53 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

Detroit, MI (KDTX), launched 12:00Z, 4.9 hours before the alert went out and 237 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: 681 J/kg
Mixed-layer CIN: -55 J/kg
Mixed-layer LCL: 1064 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 108 m²/s²
0-3 km storm-relative helicity: 105 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 2.3

Open this sounding in Storm Lab

The text

As transmitted.

565 
ACUS11 KWNS 291655
SWOMCD
SPC MCD 291654 
MIZ000-OHZ000-INZ000-ILZ000-291900-

Mesoscale Discussion 1124
NWS Storm Prediction Center Norman OK
1154 AM CDT Tue Jun 29 2021

Areas affected...Illinois...northwest Indiana...southern
Michigan...and far northwest Ohio

Concerning...Severe potential...Watch unlikely 

Valid 291654Z - 291900Z

Probability of Watch Issuance...20 percent

SUMMARY...Sporadic wind damage will be possible as storms develop
during the late morning/early afternoon hours. Severe coverage
should be limited, so a watch is not expected.

DISCUSSION...GOES visible imagery shows a couple of developing
thunderstorms and agitated cumulus along two outflow boundaries
south/southeast of the Grand Rapids, MI area and across central to
northeast IL. Ahead of these boundaries, a growing cumulus field has
developed across eastern IL into IN and southern MI, indicative of
diurnal destabilization. Further destabilization is expected through
the afternoon as temperatures continue to rise in to the upper 80s
low 90s amid dewpoints in the low 70s. Moderate instability (near
2000 J/kg MLCAPE) will be in place along/ahead of these boundaries
by early afternoon, and deep-layer shear over the region should
remain sufficient for some organized convection. Regional VWP
observations sampled 20 (35) knots of 0-3 km (0-6 km) shear, which
will likely favor thunderstorm clusters along the boundaries through
the early/mid afternoon. Sporadic wind damage will be possible,
especially if cold pools can align orthogonal to the mean
southwesterly flow/low-level shear vectors. Severe storms will
likely be limited in coverage owing to the limited spatial overlap
of favorable buoyancy and stronger winds aloft, so a watch is not
likely.

..Moore/Thompson.. 06/29/2021

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

ATTN...WFO...CLE...ILN...DTX...IWX...GRR...IND...LOT...ILX...

LAT...LON   40188896 41138791 41868687 42398616 42628525 43328363
            43188264 42928229 42378261 41808308 41418347 40948414
            40458505 40018603 39628697 39508756 39788898 40188896

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 29, 1:33 PM CDT	Mesoscale Discussion	SPC	Ashland, Ashtabula, Carroll, Columbiana, Crawford, Cuyahoga and 17 more	117 min

Nearby

Mesoscale Discussions in Indiana, 2021 Mesoscale Discussions in Michigan, 2021 Mesoscale Discussions in Illinois, 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.