Alert archive / North Carolina / Mesoscale Discussions in 2007

Mesoscale Discussion 1839

August 21, 200722 counties in North Carolina; 4 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Aug 21, 2007, 8:40 PM EDT for 22 counties in North Carolina; 4 counties in Virginia. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Aug 21, 2007, 8:40 PM EDT (00:40 UTC)
Expired: Aug 21, 2007, 10:45 PM EDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 26 counties

Beaufort County, NC, Bertie County, NC, Camden County, NC, Carteret County, NC, Chowan County, NC, Craven County, NC, Currituck County, NC, Dare County, NC, Duplin County, NC, Gates County, NC, Greene County, NC, Hyde County, NC, Jones County, NC, Lenoir County, NC, Martin County, NC, Onslow County, NC, Pamlico County, NC, Pasquotank County, NC, Perquimans County, NC, Pitt County, NC, Tyrrell County, NC, Washington County, NC, City of Chesapeake, VA, City of Portsmouth, VA, City of Suffolk, VA, City of Virginia Beach, VA

The radar

The Morehead City radar (KMHX), 99 km from the middle of the area, began a volume at 00:42 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

Newport, NC (KMHX), launched 00:00Z, 0.7 hours before the alert went out and 98 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: 2885 J/kg
Mixed-layer CIN: -85 J/kg
Mixed-layer LCL: 1160 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 42 m²/s²
0-3 km storm-relative helicity: 78 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
Aug 22, 1:43 PM EDT	Mesoscale Discussion	SPC	Alamance, Alexander, Anson, Bladen, Buncombe, Burke and 57 more	3 hr

Nearby

Mesoscale Discussions in North Carolina, 2007 Mesoscale Discussions in Virginia, 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.