Alert archive / Indiana / Mesoscale Discussions in 2015

Mesoscale Discussion 1467

July 18, 201522 counties in Indiana; 17 counties in Michigan

The Storm Prediction Center issued this mesoscale discussion at Jul 18, 2015, 4:21 PM EDT for 22 counties in Indiana; 17 counties in Michigan. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued: Jul 18, 2015, 4:21 PM EDT (20:21 UTC)
Expired: Jul 18, 2015, 5:45 PM EDT
In force: 84 min
Issued by: the Storm Prediction Center
Chance of a watch: 60%

All 39 counties

Allen County, IN, Carroll County, IN, Cass County, IN, DeKalb County, IN, Elkhart County, IN, Fulton County, IN, Grant County, IN, Howard County, IN, Huntington County, IN, Kosciusko County, IN, LaGrange County, IN, LaPorte County, IN, Marshall County, IN, Miami County, IN, Noble County, IN, Pulaski County, IN, Saint Joseph County, IN, Starke County, IN, Steuben County, IN, Wabash County, IN, White County, IN, Whitley County, IN, Allegan County, MI, Barry County, MI, Branch County, MI, Calhoun County, MI, Cass County, MI, Clinton County, MI, Eaton County, MI, Gratiot County, MI, Ionia County, MI, Kalamazoo County, MI, Kent County, MI, Mecosta County, MI, Montcalm County, MI, Newaygo County, MI, Ottawa County, MI, Saint Joseph County, MI, Van Buren County, MI

The radar

The Grand Rapids radar (KGRR), 53 km from the middle of the area, began a volume at 20:22 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.

Tornado Watch 438Jul 18, 5:00 PM EDT

The nearest sounding before it

Detroit, MI (KDTX), launched 12:00Z, 8.4 hours before the alert went out and 185 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: 1342 J/kg
Mixed-layer CIN: -42 J/kg
Mixed-layer LCL: 793 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: 26 m²/s²
0-3 km storm-relative helicity: 71 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 18, 1:26 PM EDT	Mesoscale Discussion	SPC	Adams, Allen, Blackford, Carroll, Cass, Clinton and 20 more	2 hr
Jul 18, 2:31 PM EDT	Tornado Watch	SPC	Benton, Jasper, Lake, Newton, Porter	5 hr
Jul 18, 4:59 PM EDT	Tornado Watch	SPC	Adams, Allen, Blackford, Cass, DeKalb, Elkhart and 18 more	5 hr
Jul 18, 6:43 PM EDT	Mesoscale Discussion	SPC	Allen, Cass, DeKalb, Elkhart, Fulton, Huntington and 17 more	92 min
Jul 18, 7:37 AM EDT	Mesoscale Discussion	SPC	Benzie, Lake, Manistee, Mason, Muskegon, Newaygo and 3 more	53 min

Nearby

Mesoscale Discussions in Indiana, 2015 Mesoscale Discussions in Michigan, 2015 Every mesoscale discussion in 2015

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.