Alert archive / North Carolina / Mesoscale Discussions in 2017

Mesoscale Discussion 455

April 6, 201721 counties in North Carolina; 14 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Apr 6, 2017, 12:51 AM EDT for 21 counties in North Carolina; 14 counties in Virginia. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued: Apr 6, 2017, 12:51 AM EDT (04:51 UTC)
Expired: Apr 6, 2017, 2:45 AM EDT
In force: 114 min
Issued by: the Storm Prediction Center
Chance of a watch: 60%

All 35 counties

Alamance County, NC, Anson County, NC, Caswell County, NC, Chatham County, NC, Davidson County, NC, Durham County, NC, Forsyth County, NC, Granville County, NC, Guilford County, NC, Lee County, NC, Montgomery County, NC, Moore County, NC, Orange County, NC, Person County, NC, Randolph County, NC, Richmond County, NC, Rockingham County, NC, Stokes County, NC, Surry County, NC, Vance County, NC, Yadkin County, NC, Appomattox County, VA, Bedford County, VA, Campbell County, VA, Charlotte County, VA, City of Danville, VA, City of Lynchburg, VA, City of Martinsville, VA, Floyd County, VA, Franklin County, VA, Halifax County, VA, Henry County, VA, Mecklenburg County, VA, Patrick County, VA, Pittsylvania County, VA

The radar

The Roanoke radar (KFCX), 88 km from the middle of the area, began a volume at 04:51 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

Greensboro/Hi Pt, NC (KGSO), launched 00:00Z, 4.9 hours before the alert went out and 22 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1433 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 339 m²/s²
0-3 km storm-relative helicity: 396 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
Apr 5, 11:50 PM EDT	Severe Thunderstorm Watch	SPC	Alexander, Cabarrus, Catawba, Cleveland, Davie, Gaston and 5 more	6 hr
Apr 6, 2:54 AM EDT	Mesoscale Discussion	SPC	Alamance, Anson, Cabarrus, Davidson, Guilford, Montgomery and 4 more	96 min
Apr 6, 5:59 AM EDT	Mesoscale Discussion	SPC	Alamance, Bertie, Camden, Caswell, Chatham, Chowan and 32 more	91 min
Apr 6, 7:06 AM EDT	Tornado Watch	SPC	Alamance, Bertie, Camden, Chatham, Chowan, Cumberland and 31 more	8 hr
Apr 6, 10:38 AM EDT	Mesoscale Discussion	SPC	Bertie, Chowan, Edgecombe, Gates, Greene, Halifax and 8 more	67 min
Apr 6, 12:18 PM EDT	Mesoscale Discussion	SPC	Arlington, Caroline, Charles City, Chesterfield, Essex, Fairfax and 28 more	57 min
Apr 6, 12:45 PM EDT	Severe Thunderstorm Watch	SPC	Arlington, Culpeper, Fairfax, Fauquier, King George, Loudoun and 10 more	4 hr

Nearby

Mesoscale Discussions in North Carolina, 2017 Mesoscale Discussions in Virginia, 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.