Alert archive / Kentucky / Mesoscale Discussions in 2018

Mesoscale Discussion 1435

September 8, 20186 counties in Indiana; 11 counties in Kentucky

The Storm Prediction Center issued this mesoscale discussion at Sep 8, 2018, 5:39 PM EDT for 6 counties in Indiana; 11 counties in Kentucky. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Sep 8, 2018, 5:39 PM EDT (21:39 UTC)
Expired: Sep 8, 2018, 7:45 PM EDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 40%

Counties Crawford County, IN, Floyd County, IN, Harrison County, IN, Perry County, IN, Spencer County, IN, Warrick County, IN, Breckinridge County, KY, Bullitt County, KY, Daviess County, KY, Hancock County, KY, Hardin County, KY, Jefferson County, KY, Meade County, KY, Nelson County, KY, Oldham County, KY, Shelby County, KY, Spencer County, KY

The radar

The Louisville radar (KLVX), 46 km from the middle of the area, began a volume at 21:38 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 370Sep 8, 6:05 PM EDT

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 12:00Z, 9.7 hours before the alert went out and 208 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: 613 J/kg
Mixed-layer CIN: -66 J/kg
Mixed-layer LCL: 1106 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: 42 m²/s²
0-3 km storm-relative helicity: 62 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
Sep 8, 2:56 PM EDT	Mesoscale Discussion	SPC	Harrison	3 hr
Sep 8, 7:38 PM EDT	Tornado Watch	SPC	Crawford, Floyd, Harrison, Perry	3 hr

Nearby

Mesoscale Discussions in Kentucky, 2018 Mesoscale Discussions in Indiana, 2018 Every mesoscale discussion in 2018

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.