Alert archive / Virginia / Mesoscale Discussions in 2017

Mesoscale Discussion 876

May 27, 201719 counties in North Carolina; 69 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at May 27, 2017, 6:57 PM EDT for 19 counties in North Carolina; 69 counties in Virginia. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued: May 27, 2017, 6:57 PM EDT (22:57 UTC)
Expired: May 27, 2017, 8:30 PM EDT
In force: 93 min
Issued by: the Storm Prediction Center

All 88 counties

Bertie County, NC, Camden County, NC, Chowan County, NC, Currituck County, NC, Edgecombe County, NC, Franklin County, NC, Gates County, NC, Granville County, NC, Halifax County, NC, Hertford County, NC, Martin County, NC, Northampton County, NC, Pasquotank County, NC, Perquimans County, NC, Person County, NC, Tyrrell County, NC, Vance County, NC, Warren County, NC, Washington County, NC, Albemarle County, VA, Amelia County, VA, Amherst County, VA, Appomattox County, VA, Augusta 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 Charlottesville, VA, City of Chesapeake, VA, City of Colonial Heights, VA, City of Emporia, VA, City of Franklin, VA, City of Fredericksburg, VA, City of Hampton, VA, City of Hopewell, VA, City of Lynchburg, VA, City of Newport News, VA, City of Norfolk, VA, City of Petersburg, VA, City of Poquoson, VA, City of Portsmouth, VA, City of Richmond, VA, City of Staunton, VA, City of Suffolk, VA, City of Virginia Beach, VA, City of Waynesboro, VA, City of Williamsburg, VA, Cumberland County, VA, Dinwiddie County, VA, Essex County, VA, Fluvanna County, VA, Gloucester County, VA, Goochland County, VA, Greene County, VA, Greensville 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 William County, VA, Lancaster County, VA, Louisa County, VA, Lunenburg County, VA, Mathews County, VA, Mecklenburg County, VA, Middlesex County, VA, Nelson County, VA, New Kent County, VA, Northampton County, VA, Northumberland County, VA, Nottoway County, VA, Orange County, VA, Powhatan County, VA, Prince Edward County, VA, Prince George County, VA, Richmond County, VA, Southampton County, VA, Spotsylvania County, VA, Surry County, VA, Sussex County, VA, Westmoreland County, VA, York County, VA

The radar

The Norfolk radar (KAKQ), 62 km from the middle of the area, began a volume at 23:00 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

Roanoke, VA (KRNK), launched 12:00Z, 11.0 hours before the alert went out and 162 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: 32 J/kg
Mixed-layer CIN: -429 J/kg
Mixed-layer LCL: 989 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 165 m²/s²
0-3 km storm-relative helicity: 231 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 27, 4:16 PM EDT	Mesoscale Discussion	SPC	Caswell, Granville, Halifax, Northampton, Person, Rockingham and 2 more	89 min
May 27, 4:43 PM EDT	Severe Thunderstorm Watch	SPC	Bertie, Camden, Chowan, Currituck, Edgecombe, Franklin and 11 more	5 hr
May 27, 6:11 PM EDT	Mesoscale Discussion	SPC	Alexander, Alleghany, Ashe, Avery, Burke, Caldwell and 14 more	64 min
May 27, 6:55 PM EDT	Severe Thunderstorm Watch	SPC	Alexander, Alleghany, Ashe, Avery, Buncombe, Burke and 32 more	9 hr
May 27, 1:50 PM EDT	Mesoscale Discussion	SPC	Dickenson, Lee, Wise, City of Norton	85 min
May 27, 4:11 PM EDT	Severe Thunderstorm Watch	SPC	Buchanan, Dickenson	6 hr

Nearby

Mesoscale Discussions in Virginia, 2017 Mesoscale Discussions in North Carolina, 2017 Every mesoscale discussion in 2017

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.