Alert archive / Pennsylvania / Mesoscale Discussions in 2003

Mesoscale Discussion 946

May 11, 20035 states

The Storm Prediction Center issued this mesoscale discussion at May 11, 2003, 2:52 PM EDT for 5 states. It was in force for 113 min.

The area

The outline as issued.

The facts

Issued
May 11, 2003, 2:52 PM EDT (18:52 UTC)
Expired
May 11, 2003, 4:45 PM EDT
In force
113 min
Issued by
the Storm Prediction Center
All 51 counties

Garrett County, MD, Allegany County, NY, Cattaraugus County, NY, Chautauqua County, NY, Erie County, NY, Genesee County, NY, Livingston County, NY, Monroe County, NY, Niagara County, NY, Wyoming County, NY, Ashtabula County, OH, Belmont County, OH, Carroll County, OH, Columbiana County, OH, Guernsey County, OH, Harrison County, OH, Jefferson County, OH, Mahoning County, OH, Monroe County, OH, Noble 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, Brooke County, WV, Hancock County, WV, Marshall County, WV, Monongalia County, WV, Ohio County, WV, Wetzel County, WV

The radar

The Pittsburgh radar (KPBZ), 59 km from the middle of the area, began a volume at 18:56 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, 6.9 hours before the alert went out and 70 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, Pittsburgh, PA at 12:00Z on 2003-05-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1410 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, Pittsburgh, PA at 12:00Z on 2003-05-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 188 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
1410 J/kg
Mixed-layer CIN
-36 J/kg
Mixed-layer LCL
703 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
188 m²/s²
0-3 km storm-relative helicity
137 m²/s²
Significant tornado parameter
0.6
Supercell composite
4.0

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
May 11, 11:45 AM EDTTornado WatchSPCGarrett5 hr
May 11, 3:18 PM EDTMesoscale DiscussionSPCAnne Arundel, Baltimore, Calvert, Caroline, Carroll, Charles and 14 more117 min
May 11, 10:07 AM EDTMesoscale DiscussionSPCAllegany, Broome, Cayuga, Chemung, Chenango, Cortland and 19 more113 min
May 11, 10:30 AM EDTMesoscale DiscussionSPCAllegany, Cattaraugus, Chautauqua, Erie, Genesee, Orleans and 1 more2 hr
May 11, 12:32 PM EDTMesoscale DiscussionSPCBroome, Cayuga, Chemung, Chenango, Cortland, Jefferson and 13 more118 min
May 11, 1:50 PM EDTTornado WatchSPCBroome, Cayuga, Chemung, Chenango, Cortland, Herkimer and 14 more5 hr
May 11, 3:54 PM EDTMesoscale DiscussionSPCBroome, Cayuga, Chemung, Chenango, Cortland, Herkimer and 14 more2 hr
May 10, 11:40 PM EDTMesoscale DiscussionSPCWilliams2 hr
May 11, 12:00 AM EDTTornado WatchSPCDefiance, Paulding, Van Wert, Williams6 hr
May 11, 12:28 AM EDTMesoscale DiscussionSPCAdams, Allen, Ashland, Auglaize, Brown, Butler and 44 more2 hr
May 10, 9:28 PM EDTMesoscale DiscussionSPCBoone, Clay, Fayette, Kanawha, Lincoln, Logan and 6 more62 min
May 11, 5:16 AM EDTMesoscale DiscussionSPCWayne59 min
May 11, 6:05 AM EDTSevere Thunderstorm WatchSPCWayne4 hr

Nearby

Mesoscale Discussions in Pennsylvania, 2003Mesoscale Discussions in Ohio, 2003Mesoscale Discussions in New York, 2003Every mesoscale discussion in 2003

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.