Alert archive / North Carolina / Mesoscale Discussions in 2008

Mesoscale Discussion 954

May 20, 200828 counties in North Carolina; City of Chesapeake, City of Suffolk, City of Virginia Beach, Virginia

The Storm Prediction Center issued this mesoscale discussion at May 20, 2008, 4:38 PM EDT for 28 counties in North Carolina; City of Chesapeake, City of Suffolk, City of Virginia Beach, Virginia. It was in force for 67 min.

The area

The outline as issued.

The facts

Issued: May 20, 2008, 4:38 PM EDT (20:38 UTC)
Expired: May 20, 2008, 5:45 PM EDT
In force: 67 min
Issued by: the Storm Prediction Center

All 31 counties

Alamance County, NC, Bertie County, NC, Cabarrus County, NC, Camden County, NC, Chatham County, NC, Chowan County, NC, Currituck County, NC, Durham County, NC, Edgecombe County, NC, Franklin County, NC, Gates County, NC, Halifax County, NC, Harnett County, NC, Hertford County, NC, Johnston County, NC, Lee County, NC, Martin County, NC, Montgomery County, NC, Moore County, NC, Nash County, NC, Northampton County, NC, Orange County, NC, Pasquotank County, NC, Perquimans County, NC, Randolph County, NC, Stanly County, NC, Wake County, NC, Wilson County, NC, City of Chesapeake, VA, City of Suffolk, VA, City of Virginia Beach, VA

The radar

The Raleigh/Durham radar (KRAX), 31 km from the middle of the area, began a volume at 20:40 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 nearest sounding before it

Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 8.6 hours before the alert went out and 138 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: 1458 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: 290 m²/s²
0-3 km storm-relative helicity: 276 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
May 20, 12:34 PM EDT	Mesoscale Discussion	SPC	Caswell, Northampton, Person, Vance, Warren	56 min
May 20, 1:09 PM EDT	Severe Thunderstorm Watch	SPC	Alamance, Alexander, Alleghany, Anson, Bertie, Burke and 54 more	7 hr
May 20, 2:59 PM EDT	Severe Thunderstorm Watch	SPC	Avery, Buncombe, Cherokee, Clay, Graham, Haywood and 11 more	7 hr
May 20, 3:23 PM EDT	Mesoscale Discussion	SPC	Bladen, Brunswick, Columbus, Craven, Duplin, Greene and 7 more	37 min
May 20, 3:39 PM EDT	Tornado Watch	SPC	Beaufort, Bladen, Brunswick, Carteret, Columbus, Craven and 15 more	7 hr
May 20, 7:19 PM EDT	Mesoscale Discussion	SPC	Anson, Hoke, Richmond, Scotland, Union	86 min

Nearby

Mesoscale Discussions in North Carolina, 2008 Mesoscale Discussions in Virginia, 2008 Every mesoscale discussion in 2008

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.