Alert archive / Ohio / Mesoscale Discussions in 2004

Mesoscale Discussion 797

May 21, 20046 states

The Storm Prediction Center issued this mesoscale discussion at May 21, 2004, 1:19 PM EST for 6 states. It was in force for 116 min.

The area

The outline as issued.

The facts

Issued
May 21, 2004, 1:19 PM EST (18:19 UTC)
Expired
May 21, 2004, 3:15 PM EST
In force
116 min
Issued by
the Storm Prediction Center
All 51 counties

Allen County, IN, DeKalb County, IN, Fulton County, IN, Kosciusko County, IN, Marshall County, IN, Noble County, IN, Steuben County, IN, Whitley County, IN, Macomb County, MI, Monroe County, MI, Wayne County, MI, Chautauqua County, NY, Ashland County, OH, Ashtabula County, OH, Carroll County, OH, Columbiana County, OH, Crawford County, OH, Cuyahoga County, OH, Defiance County, OH, Erie County, OH, Fulton County, OH, Geauga County, OH, Hancock County, OH, Henry County, OH, Holmes County, OH, Huron County, OH, Lake County, OH, Lorain County, OH, Lucas County, OH, Mahoning County, OH, Medina County, OH, Ottawa County, OH, Paulding County, OH, Portage County, OH, Putnam County, OH, Richland County, OH, Sandusky County, OH, Seneca County, OH, Stark County, OH, Summit County, OH, Trumbull County, OH, Tuscarawas County, OH, Wayne County, OH, Williams County, OH, Wood County, OH, Beaver County, PA, Crawford County, PA, Erie County, PA, Lawrence County, PA, Mercer County, PA, Hancock County, WV

The radar

The Cleveland radar (KCLE), 61 km from the middle of the area, began a volume at 18:22 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

Detroit, MI (KDTX), launched 12:00Z, 6.3 hours before the alert went out and 141 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, Detroit, MI at 12:00Z on 2004-05-21Temperature 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, Detroit, MI at 12:00Z on 2004-05-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 81 square meters per square second.19395878Sfc1 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
899 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
81 m²/s²
0-3 km storm-relative helicity
217 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

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.

IssuedProductOfficeCountiesLasted
May 20, 9:05 PM ESTSevere Thunderstorm WatchSPCDeKalb, Elkhart, Fulton, Jasper, Kosciusko, LaGrange and 11 more5 hr
May 21, 9:40 AM ESTMesoscale DiscussionSPCAllen, DeKalb, Elkhart, Kosciusko, LaGrange, Lake and 8 more2 hr
May 21, 12:05 PM ESTSevere Thunderstorm WatchSPCAdams, Allen, Blackford, DeKalb, Grant, Huntington and 7 more4 hr
May 21, 5:35 PM ESTTornado WatchSPCBenton, Jasper, Lake, Newton, Porter5 hr
May 21, 10:55 AM ESTSevere Thunderstorm WatchSPCBarry, Bay, Calhoun, Clinton, Eaton, Genesee and 21 more5 hr
May 21, 2:15 PM ESTSevere Thunderstorm WatchSPCAllegany, Cattaraugus6 hr
May 21, 1:40 AM ESTMesoscale DiscussionSPCAshland, Carroll, Columbiana, Coshocton, Crawford, Cuyahoga and 20 more65 min
May 21, 3:45 AM ESTMesoscale DiscussionSPCBelmont, Carroll, Columbiana, Coshocton, Fairfield, Franklin and 12 more60 min
May 21, 3:25 PM ESTSevere Thunderstorm WatchSPCAthens, Auglaize, Champaign, Clark, Clinton, Darke and 21 more6 hr
May 21, 5:35 PM ESTSevere Thunderstorm WatchSPCGallia, Meigs4 hr
May 21, 5:53 PM ESTMesoscale DiscussionSPCAdams, Allegheny, Armstrong, Bedford, Berks, Blair and 47 more97 min
May 21, 7:34 AM ESTMesoscale DiscussionSPCJefferson86 min
May 21, 4:31 PM ESTMesoscale DiscussionSPCBarbour, Berkeley, Boone, Braxton, Calhoun, Clay and 30 more89 min

Nearby

Mesoscale Discussions in Ohio, 2004Mesoscale Discussions in Indiana, 2004Mesoscale Discussions in Pennsylvania, 2004Every 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.