Alert archive / Virginia / Mesoscale Discussions in 2007

Mesoscale Discussion 1775

August 16, 2007Charles County, Saint Mary's County, Maryland; 75 counties in Virginia; 18 counties in West Virginia

The Storm Prediction Center issued this mesoscale discussion at Aug 16, 2007, 10:04 PM EDT for Charles County, Saint Mary's County, Maryland; 75 counties in Virginia; 18 counties in West Virginia. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued: Aug 16, 2007, 10:04 PM EDT (02:04 UTC)
Expired: Aug 16, 2007, 11:00 PM EDT
In force: 56 min
Issued by: the Storm Prediction Center

All 95 counties

Charles County, MD, Saint Mary's County, MD, Albemarle County, VA, Alleghany County, VA, Amelia County, VA, Amherst County, VA, Appomattox County, VA, Augusta County, VA, Bath County, VA, Bedford County, VA, Botetourt County, VA, Brunswick County, VA, Buckingham County, VA, Campbell County, VA, Caroline County, VA, Charles City County, VA, Charlotte County, VA, Chesterfield County, VA, City of Buena Vista, VA, City of Charlottesville, VA, City of Colonial Heights, VA, City of Covington, VA, City of Emporia, VA, City of Fredericksburg, VA, City of Harrisonburg, VA, City of Hopewell, VA, City of Lexington, VA, City of Lynchburg, VA, City of Petersburg, VA, City of Richmond, VA, City of Roanoke, VA, City of Salem, VA, City of Staunton, VA, City of Waynesboro, VA, Craig County, VA, Culpeper County, VA, Cumberland County, VA, Dinwiddie County, VA, Essex County, VA, Fauquier County, VA, Fluvanna County, VA, Franklin County, VA, Goochland County, VA, Greene County, VA, Greensville County, VA, Halifax County, VA, Hanover County, VA, Henrico County, VA, Highland County, VA, James City County, VA, King and Queen County, VA, King George County, VA, King William County, VA, Louisa County, VA, Lunenburg County, VA, Madison County, VA, Mecklenburg County, VA, Nelson County, VA, New Kent County, VA, Nottoway County, VA, Orange County, VA, Page County, VA, Pittsylvania County, VA, Powhatan County, VA, Prince Edward County, VA, Prince George County, VA, Prince William County, VA, Rappahannock County, VA, Richmond County, VA, Roanoke County, VA, Rockbridge County, VA, Rockingham County, VA, Spotsylvania County, VA, Stafford County, VA, Surry County, VA, Sussex County, VA, Westmoreland County, VA, Boone County, WV, Braxton County, WV, Clay County, WV, Fayette County, WV, Gilmer County, WV, Greenbrier County, WV, Kanawha County, WV, Logan County, WV, Monroe County, WV, Nicholas County, WV, Pendleton County, WV, Pocahontas County, WV, Raleigh County, WV, Randolph County, WV, Summers County, WV, Upshur County, WV, Webster County, WV, Wyoming County, WV

The radar

The Roanoke radar (KFCX), 128 km from the middle of the area, began a volume at 02:04 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.

Severe Thunderstorm Watch 611Aug 16, 11:05 PM EDT

The nearest sounding before it

Roanoke, VA (KRNK), launched 00:00Z, 2.1 hours before the alert went out and 74 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: 622 J/kg
Mixed-layer CIN: -56 J/kg
Mixed-layer LCL: 2274 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 49 m²/s²
0-3 km storm-relative helicity: 56 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

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
Aug 16, 11:07 PM EDT	Severe Thunderstorm Watch	SPC	Allegany, Anne Arundel, Baltimore, Calvert, Caroline, Carroll and 17 more	4 hr
Aug 17, 2:39 PM EDT	Mesoscale Discussion	SPC	Albemarle, Buckingham, Caroline, Clarke, Culpeper, Fairfax and 21 more	66 min

Nearby

Mesoscale Discussions in Virginia, 2007 Mesoscale Discussions in West Virginia, 2007 Mesoscale Discussions in Maryland, 2007 Every mesoscale discussion in 2007

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.