Alert archive / Virginia / Mesoscale Discussions in 2008

Mesoscale Discussion 1641

June 29, 20089 states

The Storm Prediction Center issued this mesoscale discussion at Jun 29, 2008, 9:30 PM EDT for 9 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jun 29, 2008, 9:30 PM EDT (01:30 UTC)
Expired: Jun 29, 2008, 11:30 PM EDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 199 counties

Kent County, DE, New Castle County, DE, Sussex County, DE, Berkshire County, MA, Allegany County, MD, 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, Frederick County, MD, Garrett 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, Washington County, MD, Wicomico County, MD, Worcester County, MD, Atlantic County, NJ, Bergen County, NJ, Burlington County, NJ, Camden County, NJ, Cumberland County, NJ, Essex County, NJ, Gloucester County, NJ, Hudson County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Morris County, NJ, Passaic County, NJ, Salem County, NJ, Somerset County, NJ, Sussex County, NJ, Union County, NJ, Warren County, NJ, Albany County, NY, Bronx County, NY, Clinton County, NY, Columbia County, NY, Delaware County, NY, Dutchess County, NY, Essex County, NY, Franklin County, NY, Fulton County, NY, Greene County, NY, Hamilton County, NY, Herkimer County, NY, Kings County, NY, Montgomery County, NY, New York County, NY, Orange County, NY, Otsego County, NY, Putnam County, NY, Queens County, NY, Rensselaer County, NY, Richmond County, NY, Rockland County, NY, Saratoga County, NY, Schenectady County, NY, Schoharie County, NY, St. Lawrence County, NY, Sullivan County, NY, Ulster County, NY, Warren County, NY, Washington County, NY, Westchester County, NY, Adams County, PA, Bedford County, PA, Berks County, PA, Blair County, PA, Bucks County, PA, Carbon County, PA, Centre County, PA, Chester County, PA, Columbia County, PA, Cumberland County, PA, Dauphin County, PA, Delaware County, PA, Franklin County, PA, Fulton County, PA, Huntingdon County, PA, Juniata County, PA, Lackawanna County, PA, Lancaster County, PA, Lebanon County, PA, Lehigh County, PA, Luzerne County, PA, Mifflin County, PA, Monroe County, PA, Montgomery County, PA, Montour County, PA, Northampton County, PA, Northumberland County, PA, Perry County, PA, Philadelphia County, PA, Pike County, PA, Schuylkill County, PA, Snyder County, PA, Somerset County, PA, Union County, PA, Wayne County, PA, Wyoming County, PA, York County, PA, Albemarle County, VA, Amelia County, VA, Amherst County, VA, Appomattox County, VA, Arlington County, VA, Augusta County, VA, Bath County, VA, Bedford County, VA, Botetourt County, VA, Buckingham County, VA, Campbell County, VA, Caroline County, VA, Charlotte 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 Harrisonburg, VA, City of Lexington, VA, City of Lynchburg, VA, City of Manassas, VA, City of Manassas Park, VA, City of Richmond, VA, City of Roanoke, VA, City of Salem, VA, City of Staunton, VA, City of Waynesboro, VA, City of Winchester, VA, Clarke County, VA, Culpeper County, VA, Cumberland County, VA, Essex County, VA, Fairfax County, VA, Fauquier County, VA, Fluvanna County, VA, Franklin County, VA, Frederick County, VA, Goochland County, VA, Greene County, VA, Hanover County, VA, Highland County, VA, King George County, VA, King William County, VA, Loudoun County, VA, Louisa County, VA, Madison County, VA, Nelson County, VA, Orange County, VA, Page County, VA, Powhatan County, VA, Prince Edward County, VA, Prince William County, VA, Rappahannock County, VA, Richmond County, VA, Rockbridge County, VA, Rockingham County, VA, Shenandoah County, VA, Spotsylvania County, VA, Stafford County, VA, Warren County, VA, Westmoreland County, VA, Addison County, VT, Bennington County, VT, Caledonia County, VT, Chittenden County, VT, Essex County, VT, Franklin County, VT, Grand Isle County, VT, Lamoille County, VT, Orange County, VT, Orleans County, VT, Rutland County, VT, Washington County, VT, Windham County, VT, Windsor County, VT, Berkeley County, WV, Grant County, WV, Hampshire County, WV, Hardy County, WV, Jefferson County, WV, Mineral County, WV, Morgan County, WV, Pendleton County, WV

The radar

The Philadelphia radar (KDIX), 163 km from the middle of the area, began a volume at 01:33 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

Washington/Dulle, VA (KIAD), launched 00:00Z, 1.5 hours before the alert went out and 163 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 662 J/kg
Mixed-layer CIN: -66 J/kg
Mixed-layer LCL: 1285 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 149 m²/s²
0-3 km storm-relative helicity: 168 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 2.7

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.

Issued	Product	Office	Counties	Lasted
Jun 29, 8:09 PM EDT	Severe Thunderstorm Watch	SPC	Greater Bridgeport Planning Region, Northwest Hills Planning Region	7 hr
Jun 29, 11:58 PM EDT	Mesoscale Discussion	SPC		92 min
Jun 30, 12:15 AM EDT	Mesoscale Discussion	SPC		90 min
Jun 30, 11:01 AM EDT	Mesoscale Discussion	SPC	Allegany, Garrett	119 min
Jun 30, 7:52 PM EDT	Mesoscale Discussion	SPC	Anne Arundel, Baltimore, Calvert, Carroll, Cecil, Charles and 11 more	113 min
Jun 30, 2:16 PM EDT	Mesoscale Discussion	SPC	Middlesex	89 min
Jun 29, 8:35 PM EDT	Mesoscale Discussion	SPC	Brunswick, Greensville, Isle of Wight, Southampton, Sussex, City of Chesapeake and 8 more	85 min

Nearby

Mesoscale Discussions in Virginia, 2008 Mesoscale Discussions in Pennsylvania, 2008 Mesoscale Discussions in New York, 2008 Every mesoscale discussion in 2008

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.