Alert archive / Ohio / Mesoscale Discussions in 2012

Mesoscale Discussion 1912

September 7, 20125 states

The Storm Prediction Center issued this mesoscale discussion at Sep 7, 2012, 2:16 PM EDT for 5 states. It was in force for 59 min.

The area

The outline as issued.

The facts

Issued: Sep 7, 2012, 2:16 PM EDT (18:16 UTC)
Expired: Sep 7, 2012, 3:15 PM EDT
In force: 59 min
Issued by: the Storm Prediction Center

All 60 counties

Fayette County, IN, Henry County, IN, Randolph County, IN, Rush County, IN, Union County, IN, Wayne County, IN, Cattaraugus County, NY, Chautauqua County, NY, Allen County, OH, Ashland County, OH, Auglaize County, OH, Carroll County, OH, Champaign County, OH, Clark County, OH, Columbiana County, OH, Coshocton County, OH, Crawford County, OH, Darke County, OH, Delaware County, OH, Franklin County, OH, Geauga County, OH, Hancock County, OH, Hardin County, OH, Holmes County, OH, Huron County, OH, Knox County, OH, Licking County, OH, Logan County, OH, Madison County, OH, Mahoning County, OH, Marion County, OH, Medina County, OH, Mercer County, OH, Miami County, OH, Montgomery County, OH, Morrow County, OH, Portage County, OH, Preble County, OH, Putnam County, OH, Richland County, OH, Seneca County, OH, Shelby County, OH, Stark County, OH, Summit County, OH, Trumbull County, OH, Tuscarawas County, OH, Union County, OH, Wayne County, OH, Wyandot County, OH, Beaver County, PA, Butler County, PA, Clarion County, PA, Crawford County, PA, Erie County, PA, Forest County, PA, Lawrence County, PA, Mercer County, PA, Venango County, PA, Warren County, PA, Hancock County, WV

The radar

The Cleveland radar (KCLE), 69 km from the middle of the area, began a volume at 18:16 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.

The nearest sounding before it

Pittsburgh, PA (KPIT), launched 12:00Z, 6.3 hours before the alert went out and 192 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: 1010 J/kg
Mixed-layer CIN: -40 J/kg
Mixed-layer LCL: 1160 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 28 m²/s²
0-3 km storm-relative helicity: 41 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 3.3

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
Sep 7, 11:09 AM EDT	Mesoscale Discussion	SPC	Adams, Allen, Bartholomew, Blackford, Boone, Brown and 44 more	2 hr
Sep 7, 11:36 AM EDT	Severe Thunderstorm Watch	SPC	Adams, Allen, Blackford, Boone, Carroll, Cass and 38 more	6 hr
Sep 7, 1:16 PM EDT	Mesoscale Discussion	SPC	Adams, Delaware, Fayette, Hancock, Henry, Jay and 4 more	59 min
Sep 7, 3:39 PM EDT	Mesoscale Discussion	SPC	Dearborn, Franklin, Union	66 min
Sep 7, 4:22 PM EDT	Mesoscale Discussion	SPC	Bartholomew, Boone, Brown, Clay, Dearborn, Decatur and 27 more	53 min
Sep 7, 4:41 PM EDT	Severe Thunderstorm Watch	SPC	Bartholomew, Brown, Clay, Daviess, Dearborn, Decatur and 25 more	6 hr
Sep 7, 4:44 PM EDT	Mesoscale Discussion	SPC	Posey, Vanderburgh	2 hr
Sep 7, 6:15 PM EDT	Severe Thunderstorm Watch	SPC	Gibson, Pike, Posey, Spencer, Vanderburgh, Warrick	7 hr
Sep 7, 6:38 PM EDT	Mesoscale Discussion	SPC	Allegany, Cattaraugus, Chautauqua, Livingston, Steuben, Wyoming	97 min
Sep 7, 3:22 PM EDT	Severe Thunderstorm Watch	SPC	Ashland, Ashtabula, Carroll, Columbiana, Coshocton, Crawford and 18 more	4 hr

Nearby

Mesoscale Discussions in Ohio, 2012 Mesoscale Discussions in Pennsylvania, 2012 Mesoscale Discussions in Indiana, 2012 Every 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.