Alert archive / Indiana / Mesoscale Discussions in 2012

Mesoscale Discussion 1980

September 21, 201216 counties in Illinois; 30 counties in Indiana; 7 counties in Ohio

The Storm Prediction Center issued this mesoscale discussion at Sep 21, 2012, 6:30 PM CDT for 16 counties in Illinois; 30 counties in Indiana; 7 counties in Ohio. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Sep 21, 2012, 6:30 PM CDT (23:30 UTC)
Expired
Sep 21, 2012, 9:00 PM CDT
In force
3 hr
Issued by
the Storm Prediction Center
Chance of a watch
20%
All 53 counties

Clark County, IL, Clay County, IL, Coles County, IL, Crawford County, IL, Cumberland County, IL, Douglas County, IL, Edgar County, IL, Edwards County, IL, Effingham County, IL, Jasper County, IL, Lawrence County, IL, Moultrie County, IL, Richland County, IL, Shelby County, IL, Wabash County, IL, Wayne County, IL, Bartholomew County, IN, Boone County, IN, Brown County, IN, Clay County, IN, Dearborn County, IN, Decatur County, IN, Fayette County, IN, Franklin County, IN, Greene County, IN, Hamilton County, IN, Hancock County, IN, Hendricks County, IN, Henry County, IN, Johnson County, IN, Knox County, IN, Marion County, IN, Monroe County, IN, Montgomery County, IN, Morgan County, IN, Owen County, IN, Parke County, IN, Putnam County, IN, Ripley County, IN, Rush County, IN, Shelby County, IN, Sullivan County, IN, Union County, IN, Vermillion County, IN, Vigo County, IN, Wayne County, IN, Butler County, OH, Clinton County, OH, Greene County, OH, Hamilton County, OH, Montgomery County, OH, Preble County, OH, Warren County, OH

The radar

The Indianapolis radar (KIND), 70 km from the middle of the area, began a volume at 23:30 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, 11.5 hours before the alert went out and 193 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 2012-09-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2012-09-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 120 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2528 m above ground
0-6 km bulk shear
63 kt
0-1 km storm-relative helicity
120 m²/s²
0-3 km storm-relative helicity
152 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.

IssuedProductOfficeCountiesLasted
Sep 21, 1:36 PM CDTMesoscale DiscussionSPCBureau, Cass, Champaign, Christian, Clark, Clay and 40 more84 min
Sep 21, 4:59 PM CDTMesoscale DiscussionSPCBond, Clay, Clinton, Crawford, Cumberland, Edwards and 23 more91 min

Nearby

Mesoscale Discussions in Indiana, 2012Mesoscale Discussions in Illinois, 2012Mesoscale Discussions in Ohio, 2012Every mesoscale discussion in 2012

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.