Alert archive / West Virginia / Mesoscale Discussions in 2004

Mesoscale Discussion 1501

July 4, 20045 states

The Storm Prediction Center issued this mesoscale discussion at Jul 4, 2004, 3:00 PM EDT for 5 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Jul 4, 2004, 3:00 PM EDT (19:00 UTC)
Expired
Jul 4, 2004, 5:00 PM EDT
In force
2 hr
Issued by
the Storm Prediction Center
All 61 counties

Garrett County, MD, Allegany County, NY, Cattaraugus County, NY, Chautauqua County, NY, Erie County, NY, Genesee County, NY, Wyoming County, NY, Ashtabula County, OH, Columbiana County, OH, Jefferson County, OH, Mahoning County, OH, Trumbull County, OH, Allegheny County, PA, Armstrong County, PA, Beaver County, PA, Butler County, PA, Cambria County, PA, Cameron County, PA, Clarion County, PA, Clearfield County, PA, Crawford County, PA, Elk County, PA, Erie County, PA, Fayette County, PA, Forest County, PA, Greene County, PA, Indiana County, PA, Jefferson County, PA, Lawrence County, PA, McKean County, PA, Mercer County, PA, Somerset County, PA, Venango County, PA, Warren County, PA, Washington County, PA, Westmoreland County, PA, Barbour County, WV, Braxton County, WV, Brooke County, WV, Calhoun County, WV, Clay County, WV, Doddridge County, WV, Fayette County, WV, Gilmer County, WV, Hancock County, WV, Harrison County, WV, Lewis County, WV, Marion County, WV, Marshall County, WV, Monongalia County, WV, Nicholas County, WV, Ohio County, WV, Preston County, WV, Randolph County, WV, Ritchie County, WV, Taylor County, WV, Tucker County, WV, Tyler County, WV, Upshur County, WV, Webster County, WV, Wetzel County, WV

The radar

The Pittsburgh radar (KPBZ), 43 km from the middle of the area, began a volume at 19:00 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

Washington/Dulle, VA (KIAD), launched 12:00Z, 7.0 hours before the alert went out and 268 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, Washington/Dulle, VA at 12:00Z on 2004-07-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1158 joules per kilogram.LCLLFCEL10008507005003002001001 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, Washington/Dulle, VA at 12:00Z on 2004-07-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 90 square meters per square second.1939Sfc1 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
1158 J/kg
Mixed-layer CIN
-3 J/kg
Mixed-layer LCL
547 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
90 m²/s²
0-3 km storm-relative helicity
64 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.2

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
Jul 4, 4:55 PM EDTMesoscale DiscussionSPCAllegany, Garrett65 min
Jul 4, 11:08 AM EDTMesoscale DiscussionSPCAllegany, Cattaraugus, Chautauqua, Erie, Genesee, Wyoming3 hr
Jul 4, 3:55 PM EDTSevere Thunderstorm WatchSPCAllegany, Cattaraugus, Cayuga, Chautauqua, Chemung, Erie and 12 more6 hr
Jul 4, 7:29 PM EDTMesoscale DiscussionSPCAllegany, Genesee, Livingston, Monroe, Ontario, Orleans and 3 more61 min
Jul 4, 12:50 PM EDTSevere Thunderstorm WatchSPCAshtabula, Athens, Belmont, Carroll, Columbiana, Coshocton and 23 more5 hr

Nearby

Mesoscale Discussions in West Virginia, 2004Mesoscale Discussions in Pennsylvania, 2004Mesoscale Discussions in New York, 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.