Alert archive / Virginia / Mesoscale Discussions in 2007

Mesoscale Discussion 1492

July 16, 2007Sussex County, Delaware; 12 counties in Maryland; 103 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Jul 16, 2007, 12:40 PM EDT for Sussex County, Delaware; 12 counties in Maryland; 103 counties in Virginia. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jul 16, 2007, 12:40 PM EDT (16:40 UTC)
Expired: Jul 16, 2007, 2:45 PM EDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 116 counties

Sussex County, DE, Anne Arundel County, MD, Calvert County, MD, Caroline County, MD, Charles County, MD, Dorchester County, MD, Prince George's County, MD, Queen Anne's County, MD, Saint Mary's County, MD, Somerset County, MD, Talbot County, MD, Wicomico County, MD, Worcester County, MD, Accomack County, VA, Albemarle County, VA, Amelia County, VA, Amherst County, VA, Appomattox County, VA, Arlington County, VA, Augusta County, VA, Bedford County, VA, Botetourt County, VA, Brunswick County, VA, Buckingham County, VA, Campbell County, VA, Caroline County, VA, Carroll County, VA, Charles City County, VA, Charlotte County, VA, Chesterfield County, VA, City of Alexandria, VA, City of Buena Vista, VA, City of Charlottesville, VA, City of Chesapeake, VA, City of Colonial Heights, VA, City of Fairfax, VA, City of Falls Church, VA, City of Fredericksburg, VA, City of Galax, VA, City of Hampton, VA, City of Harrisonburg, VA, City of Hopewell, VA, City of Lexington, VA, City of Lynchburg, VA, City of Manassas, VA, City of Manassas Park, VA, City of Martinsville, VA, City of Newport News, VA, City of Norfolk, VA, City of Petersburg, VA, City of Poquoson, VA, City of Portsmouth, VA, City of Radford, VA, City of Richmond, VA, City of Roanoke, VA, City of Salem, VA, City of Staunton, VA, City of Suffolk, VA, City of Virginia Beach, VA, City of Waynesboro, VA, City of Williamsburg, VA, Culpeper County, VA, Cumberland County, VA, Dinwiddie County, VA, Essex County, VA, Fairfax County, VA, Fauquier County, VA, Floyd County, VA, Fluvanna County, VA, Franklin County, VA, Gloucester County, VA, Goochland County, VA, Greene County, VA, Halifax County, VA, Hanover County, VA, Henrico County, VA, Isle of Wight County, VA, James City County, VA, King and Queen County, VA, King George County, VA, King William County, VA, Lancaster County, VA, Louisa County, VA, Lunenburg County, VA, Madison County, VA, Mathews County, VA, Middlesex County, VA, Montgomery County, VA, Nelson County, VA, New Kent County, VA, Northampton County, VA, Northumberland County, VA, Nottoway County, VA, Orange County, VA, Page County, VA, Patrick County, VA, Pittsylvania County, VA, Powhatan County, VA, Prince Edward County, VA, Prince George County, VA, Prince William County, VA, Pulaski County, VA, Rappahannock County, VA, Richmond County, VA, Roanoke County, VA, Rockbridge County, VA, Smyth County, VA, Southampton County, VA, Spotsylvania County, VA, Stafford County, VA, Surry County, VA, Sussex County, VA, Warren County, VA, Westmoreland County, VA, Wythe County, VA, York County, VA

The radar

The Norfolk radar (KAKQ), 141 km from the middle of the area, began a volume at 16:40 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 523Jul 16, 2:00 PM EDT

The nearest sounding before it

Roanoke, VA (KRNK), launched 12:00Z, 4.7 hours before the alert went out and 132 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: 638 J/kg
Mixed-layer CIN: -77 J/kg
Mixed-layer LCL: 930 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: 5 m²/s²
0-3 km storm-relative helicity: 8 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.

Issued	Product	Office	Counties	Lasted
Jul 16, 1:58 PM EDT	Severe Thunderstorm Watch	SPC	Kent, New Castle, Sussex	7 hr
Jul 16, 3:51 PM EDT	Mesoscale Discussion	SPC	Kent, New Castle, Sussex	84 min
Jul 16, 7:53 PM EDT	Mesoscale Discussion	SPC	Kent, New Castle, Sussex	97 min

Nearby

Mesoscale Discussions in Virginia, 2007 Mesoscale Discussions in Maryland, 2007 Mesoscale Discussions in Delaware, 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.