Alert archive / Indiana / Mesoscale Discussions in 2018

Mesoscale Discussion 1326

August 20, 201827 counties in Indiana

The Storm Prediction Center issued this mesoscale discussion at Aug 20, 2018, 2:27 PM EDT for 27 counties in Indiana. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Aug 20, 2018, 2:27 PM EDT (18:27 UTC)
Expired
Aug 20, 2018, 4:30 PM EDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
20%
All 27 counties

Blackford County, IN, Boone County, IN, Carroll County, IN, Cass County, IN, Clinton County, IN, Delaware County, IN, Fulton County, IN, Grant County, IN, Hamilton County, IN, Hancock County, IN, Hendricks County, IN, Henry County, IN, Howard County, IN, Jasper County, IN, Johnson County, IN, Madison County, IN, Marion County, IN, Miami County, IN, Montgomery County, IN, Newton County, IN, Pulaski County, IN, Shelby County, IN, Starke County, IN, Tippecanoe County, IN, Tipton County, IN, Wabash County, IN, White County, IN

The radar

The Indianapolis radar (KIND), 88 km from the middle of the area, began a volume at 18:30 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, 6.5 hours before the alert went out and 197 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-pSkew-T log-p diagram, Lincoln, IL at 12:00Z on 2018-08-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 367 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 12:00Z on 2018-08-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 166 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
367 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
470 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
166 m²/s²
0-3 km storm-relative helicity
158 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.4

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.

IssuedProductOfficeCountiesLasted
Aug 20, 5:45 PM EDTSevere Thunderstorm WatchSPCCrawford, Dubois, Gibson, Perry, Pike, Posey and 3 more6 hr

Nearby

Mesoscale Discussions in Indiana, 2018Every 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.