Alert archive / Ohio / Mesoscale Discussions in 2004

Mesoscale Discussion 406

April 21, 20044 states

The Storm Prediction Center issued this mesoscale discussion at Apr 21, 2004, 12:48 PM EDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Apr 21, 2004, 12:48 PM EDT (16:48 UTC)
Expired: Apr 21, 2004, 3:15 PM EDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 43 counties

Allegany County, NY, Cattaraugus County, NY, Chautauqua County, NY, Erie County, NY, Genesee County, NY, Livingston County, NY, Monroe County, NY, Niagara County, NY, Ontario County, NY, Orleans County, NY, Wayne County, NY, Wyoming County, NY, Ashland County, OH, Ashtabula County, OH, Carroll County, OH, Columbiana County, OH, Coshocton County, OH, Geauga County, OH, Harrison County, OH, Holmes County, OH, Jefferson County, OH, Knox County, OH, Lake County, OH, Mahoning County, OH, Medina County, OH, Portage County, OH, Stark County, OH, Summit County, OH, Trumbull County, OH, Tuscarawas County, OH, Wayne County, OH, Beaver County, PA, Butler County, PA, Clarion County, PA, Crawford County, PA, Erie County, PA, Forest County, PA, Lawrence County, PA, McKean County, PA, Mercer County, PA, Venango County, PA, Warren County, PA, Hancock County, WV

The radar

The Buffalo radar (KBUF), 87 km from the middle of the area, began a volume at 16:50 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

Pittsburgh, PA (KPIT), launched 12:00Z, 4.8 hours before the alert went out and 218 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: 2 J/kg
Mixed-layer CIN: -88 J/kg
Mixed-layer LCL: 1357 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 178 m²/s²
0-3 km storm-relative helicity: 283 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
Apr 20, 9:55 PM EDT	Mesoscale Discussion	SPC	Defiance, Paulding, Williams	65 min
Apr 21, 2:16 PM EDT	Mesoscale Discussion	SPC	Allen, Defiance, Fulton, Henry, Lucas, Mercer and 5 more	2 hr

Nearby

Mesoscale Discussions in Ohio, 2004 Mesoscale Discussions in New York, 2004 Mesoscale Discussions in Pennsylvania, 2004 Every mesoscale discussion in 2004

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.