Alert archive / Indiana / Mesoscale Discussions in 2017

Mesoscale Discussion 1541

August 21, 20179 counties in Illinois; 38 counties in Indiana

The Storm Prediction Center issued this mesoscale discussion at Aug 21, 2017, 12:41 PM CDT for 9 counties in Illinois; 38 counties in Indiana. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued: Aug 21, 2017, 12:41 PM CDT (17:41 UTC)
Expired: Aug 21, 2017, 2:15 PM CDT
In force: 94 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 47 counties

Clark County, IL, Coles County, IL, Crawford County, IL, Cumberland County, IL, Edgar County, IL, Effingham County, IL, Jasper County, IL, Lawrence County, IL, Richland County, IL, Blackford County, IN, Boone County, IN, Carroll County, IN, Cass County, IN, Clay County, IN, Clinton County, IN, Delaware County, IN, Fountain County, IN, Grant County, IN, Greene County, IN, Hamilton County, IN, Hancock County, IN, Hendricks County, IN, Henry County, IN, Howard County, IN, Huntington County, IN, Jay County, IN, Johnson County, IN, Madison County, IN, Marion County, IN, Miami County, IN, Monroe County, IN, Montgomery County, IN, Morgan County, IN, Owen County, IN, Parke County, IN, Putnam County, IN, Randolph County, IN, Rush County, IN, Shelby County, IN, Sullivan County, IN, Tippecanoe County, IN, Tipton County, IN, Vermillion County, IN, Vigo County, IN, Wabash County, IN, Wayne County, IN, Wells County, IN

The radar

The Indianapolis radar (KIND), 61 km from the middle of the area, began a volume at 17:45 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

Lincoln, IL (KILX), launched 12:00Z, 5.7 hours before the alert went out and 145 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: 1645 J/kg
Mixed-layer CIN: -103 J/kg
Mixed-layer LCL: 992 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: 85 m²/s²
0-3 km storm-relative helicity: 117 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 21, 3:29 PM CDT	Mesoscale Discussion	SPC	Bond, Calhoun, Clark, Clay, Clinton, Crawford and 22 more	91 min

Nearby

Mesoscale Discussions in Indiana, 2017 Mesoscale Discussions in Illinois, 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.