Alert archive / Pennsylvania / Mesoscale Discussions in 2003

Mesoscale Discussion 2423

September 27, 20035 states

The Storm Prediction Center issued this mesoscale discussion at Sep 27, 2003, 2:22 PM EDT for 5 states. It was in force for 113 min.

The area

The outline as issued.

The facts

Issued
Sep 27, 2003, 2:22 PM EDT (18:22 UTC)
Expired
Sep 27, 2003, 4:15 PM EDT
In force
113 min
Issued by
the Storm Prediction Center
All 45 counties

Frederick County, MD, Washington County, MD, Broome County, NY, Cayuga County, NY, Chemung County, NY, Ontario County, NY, Schuyler County, NY, Seneca County, NY, Steuben County, NY, Tioga County, NY, Tompkins County, NY, Yates County, NY, Adams County, PA, Bedford County, PA, Bradford County, PA, Centre County, PA, Clinton County, PA, Columbia County, PA, Cumberland County, PA, Dauphin County, PA, Franklin County, PA, Fulton County, PA, Huntingdon County, PA, Juniata County, PA, Lycoming County, PA, Mifflin County, PA, Montour County, PA, Northumberland County, PA, Perry County, PA, Potter County, PA, Snyder County, PA, Sullivan County, PA, Tioga County, PA, Union County, PA, City of Winchester, VA, Clarke County, VA, Frederick County, VA, Loudoun County, VA, Shenandoah County, VA, Warren County, VA, Berkeley County, WV, Hampshire County, WV, Hardy County, WV, Jefferson County, WV, Morgan County, WV

The radar

The State College radar (KCCX), 34 km from the middle of the area, began a volume at 18:21 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, 6.4 hours before the alert went out and 196 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 2003-09-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 24 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 2003-09-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 40 square meters per square second.193958Sfc1 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
24 J/kg
Mixed-layer CIN
-336 J/kg
Mixed-layer LCL
757 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
40 m²/s²
0-3 km storm-relative helicity
81 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.

IssuedProductOfficeCountiesLasted
Sep 27, 4:05 PM EDTSevere Thunderstorm WatchSPCAllegany, Garrett, Washington5 hr
Sep 27, 6:52 PM EDTMesoscale DiscussionSPCAllegany, Washington53 min
Sep 27, 1:58 AM EDTMesoscale DiscussionSPCAllegany, Cattaraugus, Cayuga, Erie, Genesee, Livingston and 9 more62 min
Sep 27, 2:35 AM EDTTornado WatchSPCAllegany, Cattaraugus, Chautauqua, Erie, Genesee, Livingston and 6 more5 hr
Sep 27, 6:39 AM EDTMesoscale DiscussionSPCAllegany, Cattaraugus, Chautauqua, Erie, Livingston, Wyoming96 min
Sep 27, 12:06 AM EDTMesoscale DiscussionSPCAllegheny, Armstrong, Beaver, Butler, Crawford, Lawrence and 3 more84 min
Sep 27, 12:40 AM EDTTornado WatchSPCBeaver, Butler, Crawford, Forest, Lawrence, Mercer and 2 more5 hr
Sep 27, 3:37 AM EDTMesoscale DiscussionSPCAllegheny, Armstrong, Beaver, Butler, Cambria, Cameron and 17 more113 min
Sep 27, 5:15 AM EDTMesoscale DiscussionSPCBeaver, Crawford, Lawrence, Mercer, Venango, Warren60 min
Sep 27, 11:42 AM EDTMesoscale DiscussionSPCDickenson, Lee, Russell, Scott, Wise, City of Norton108 min
Sep 27, 2:41 PM EDTMesoscale DiscussionSPCAlleghany, Bedford, Bland, Botetourt, Carroll, Craig and 17 more2 hr

Nearby

Mesoscale Discussions in Pennsylvania, 2003Mesoscale Discussions in New York, 2003Mesoscale Discussions in Virginia, 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.