Alert archive / Virginia / Mesoscale Discussions in 2013

Mesoscale Discussion 459

April 12, 201312 counties in North Carolina; 16 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Apr 12, 2013, 7:25 AM EDT for 12 counties in North Carolina; 16 counties in Virginia. It was in force for 65 min.

The area

The outline as issued.

The facts

Issued: Apr 12, 2013, 7:25 AM EDT (11:25 UTC)
Expired: Apr 12, 2013, 8:30 AM EDT
In force: 65 min
Issued by: the Storm Prediction Center

All 28 counties

Edgecombe County, NC, Franklin County, NC, Greene County, NC, Halifax County, NC, Johnston County, NC, Nash County, NC, Northampton County, NC, Sampson County, NC, Vance County, NC, Warren County, NC, Wayne County, NC, Wilson County, NC, Brunswick County, VA, Charles City County, VA, Chesterfield County, VA, City of Colonial Heights, VA, City of Emporia, VA, City of Hopewell, VA, City of Petersburg, VA, City of Richmond, VA, Dinwiddie County, VA, Greensville County, VA, Henrico County, VA, New Kent County, VA, Nottoway County, VA, Prince George County, VA, Southampton County, VA, Sussex County, VA

The radar

The Raleigh/Durham radar (KRAX), 98 km from the middle of the area, began a volume at 11:24 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 00:00Z, 11.4 hours before the alert went out and 187 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: 1699 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 81 m²/s²
0-3 km storm-relative helicity: 85 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
Apr 11, 8:24 PM EDT	Tornado Watch	SPC	Alexander, Burke, Cabarrus, Caldwell, Catawba, Cleveland and 10 more	8 hr
Apr 11, 9:19 PM EDT	Mesoscale Discussion	SPC	Cherokee, Graham, Haywood, Jackson, Macon, Madison and 1 more	86 min
Apr 11, 10:52 PM EDT	Mesoscale Discussion	SPC	Cleveland, Henderson, Polk, Rutherford, Transylvania	83 min
Apr 12, 12:46 AM EDT	Mesoscale Discussion	SPC	Columbus	89 min
Apr 12, 1:06 AM EDT	Tornado Watch	SPC	Bladen, Brunswick, Columbus, New Hanover, Pender, Robeson	6 hr
Apr 12, 1:58 AM EDT	Mesoscale Discussion	SPC	Alamance, Bertie, Caswell, Chatham, Cumberland, Davidson and 34 more	92 min
Apr 12, 2:57 AM EDT	Tornado Watch	SPC	Alamance, Anson, Chatham, Cumberland, Davidson, Durham and 25 more	6 hr
Apr 12, 4:00 AM EDT	Mesoscale Discussion	SPC	Bladen, Brunswick, Columbus, New Hanover, Pender, Robeson and 1 more	90 min
Apr 12, 5:21 AM EDT	Tornado Watch	SPC	Northampton	3 hr
Apr 12, 2:34 PM EDT	Mesoscale Discussion	SPC	Beaufort, Bertie, Bladen, Camden, Chowan, Columbus and 15 more	116 min
Apr 12, 5:05 AM EDT	Mesoscale Discussion	SPC	Albemarle, Amelia, Amherst, Appomattox, Brunswick, Buckingham and 34 more	85 min

Nearby

Mesoscale Discussions in Virginia, 2013 Mesoscale Discussions in North Carolina, 2013 Every mesoscale discussion in 2013

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.