Alert archive / Virginia / Mesoscale Discussions in 2003

Mesoscale Discussion 1684

July 7, 20036 states

The Storm Prediction Center issued this mesoscale discussion at Jul 7, 2003, 6:29 PM EDT for 6 states. It was in force for 61 min.

The area

The outline as issued.

The facts

Issued
Jul 7, 2003, 6:29 PM EDT (22:29 UTC)
Expired
Jul 7, 2003, 7:30 PM EDT
In force
61 min
Issued by
the Storm Prediction Center
All 94 counties

Kent County, DE, New Castle County, DE, Anne Arundel County, MD, Baltimore County, MD, Calvert County, MD, Caroline County, MD, Carroll County, MD, Cecil County, MD, Charles County, MD, City of Baltimore, MD, Dorchester County, MD, Harford County, MD, Howard County, MD, Kent County, MD, Montgomery County, MD, Prince George's County, MD, Queen Anne's County, MD, Saint Mary's County, MD, Talbot County, MD, Bergen County, NJ, Camden County, NJ, Essex County, NJ, Gloucester County, NJ, Hudson County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Morris County, NJ, Passaic County, NJ, Salem County, NJ, Somerset County, NJ, Sussex County, NJ, Union County, NJ, Warren County, NJ, Bronx County, NY, New York County, NY, Orange County, NY, Putnam County, NY, Richmond County, NY, Rockland County, NY, Westchester County, NY, Berks County, PA, Bucks County, PA, Carbon County, PA, Chester County, PA, Delaware County, PA, Lancaster County, PA, Lehigh County, PA, Monroe County, PA, Montgomery County, PA, Northampton County, PA, Philadelphia County, PA, Pike County, PA, York County, PA, Albemarle County, VA, Amherst County, VA, Arlington County, VA, Augusta County, VA, Bedford County, VA, Botetourt County, VA, Buckingham County, VA, Caroline County, VA, City of Alexandria, VA, City of Buena Vista, VA, City of Charlottesville, VA, City of Fairfax, VA, City of Falls Church, VA, City of Fredericksburg, VA, City of Lexington, VA, City of Lynchburg, VA, City of Manassas, VA, City of Manassas Park, VA, City of Roanoke, VA, City of Staunton, VA, City of Waynesboro, VA, Culpeper County, VA, Cumberland County, VA, Essex County, VA, Fairfax County, VA, Fauquier County, VA, Fluvanna County, VA, Goochland County, VA, Greene County, VA, Hanover County, VA, King George County, VA, Louisa County, VA, Madison County, VA, Nelson County, VA, Orange County, VA, Prince William County, VA, Rockbridge County, VA, Spotsylvania County, VA, Stafford County, VA, Westmoreland County, VA

The radar

The Sterling radar (KLWX), 31 km from the middle of the area, began a volume at 22:31 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

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 10.5 hours before the alert went out and 104 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, Phillips Aaf/Abe, MD at 12:00Z on 2003-07-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 38 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Phillips Aaf/Abe, MD at 12:00Z on 2003-07-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 30 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
38 J/kg
Mixed-layer CIN
-216 J/kg
Mixed-layer LCL
1117 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
30 m²/s²
0-3 km storm-relative helicity
49 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
Jul 7, 2:55 PM EDTSevere Thunderstorm WatchSPC5 hr
Jul 7, 2:23 PM EDTMesoscale DiscussionSPCKent, New Castle, Sussex67 min
Jul 7, 12:10 PM EDTMesoscale DiscussionSPCEssex, Hunterdon, Morris, Passaic, Somerset, Sussex and 1 more65 min
Jul 7, 2:56 PM EDTMesoscale DiscussionSPCAllegheny, Beaver, Butler, Crawford, Greene, Lawrence and 3 more94 min
Jul 7, 3:10 PM EDTSevere Thunderstorm WatchSPCAllegheny, Armstrong, Beaver, Butler, Cambria, Cameron and 14 more6 hr
Jul 7, 6:52 PM EDTMesoscale DiscussionSPCAllegheny, Armstrong, Beaver, Butler, Cameron, Clarion and 12 more53 min

Nearby

Mesoscale Discussions in Virginia, 2003Mesoscale Discussions in Maryland, 2003Mesoscale Discussions in New Jersey, 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.