Alert archive / North Carolina / Mesoscale Discussions in 2009

Mesoscale Discussion 749

May 7, 200938 counties in North Carolina; 6 counties in South Carolina; 8 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at May 7, 2009, 7:33 PM EDT for 38 counties in North Carolina; 6 counties in South Carolina; 8 counties in Virginia. It was in force for 57 min.

The area

The outline as issued.

The facts

Issued
May 7, 2009, 7:33 PM EDT (23:33 UTC)
Expired
May 7, 2009, 8:30 PM EDT
In force
57 min
Issued by
the Storm Prediction Center
All 52 counties

Beaufort County, NC, Bertie County, NC, Bladen County, NC, Brunswick County, NC, Camden County, NC, Carteret County, NC, Chowan County, NC, Columbus County, NC, Craven County, NC, Cumberland County, NC, Currituck County, NC, Dare County, NC, Duplin County, NC, Edgecombe County, NC, Gates County, NC, Greene County, NC, Hertford County, NC, Hoke County, NC, Hyde County, NC, Johnston County, NC, Jones County, NC, Lenoir County, NC, Martin County, NC, New Hanover County, NC, Northampton County, NC, Onslow County, NC, Pamlico County, NC, Pasquotank County, NC, Pender County, NC, Perquimans County, NC, Pitt County, NC, Robeson County, NC, Sampson County, NC, Scotland County, NC, Tyrrell County, NC, Washington County, NC, Wayne County, NC, Wilson County, NC, Dillon County, SC, Florence County, SC, Georgetown County, SC, Horry County, SC, Marion County, SC, Marlboro County, SC, City of Chesapeake, VA, City of Franklin, VA, City of Norfolk, VA, City of Portsmouth, VA, City of Suffolk, VA, City of Virginia Beach, VA, Isle of Wight County, VA, Southampton County, VA

The radar

The Raleigh/Durham radar (KRAX), 77 km from the middle of the area, began a volume at 23:34 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 12:00Z, 11.6 hours before the alert went out and 104 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-pSkew-T log-p diagram, Newport, NC at 12:00Z on 2009-05-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1243 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Newport, NC at 12:00Z on 2009-05-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 143 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
1243 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
583 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
143 m²/s²
0-3 km storm-relative helicity
126 m²/s²
Significant tornado parameter
0.8
Supercell composite
6.6

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.

IssuedProductOfficeCountiesLasted
May 6, 8:26 PM EDTTornado WatchSPCAlamance, Anson, Bertie, Camden, Caswell, Chatham and 30 more8 hr
May 6, 10:50 PM EDTMesoscale DiscussionSPCAlamance, Caswell, Durham, Franklin, Granville, Halifax and 8 more55 min
May 6, 11:44 PM EDTMesoscale DiscussionSPCBuncombe, Burke, Cherokee, Clay, Graham, Haywood and 11 more91 min
May 7, 12:10 AM EDTMesoscale DiscussionSPCAlamance, Caswell, Chatham, Durham, Franklin, Granville and 9 more95 min
May 7, 5:17 AM EDTMesoscale DiscussionSPCAlamance, Anson, Beaufort, Bertie, Bladen, Brunswick and 58 more118 min
May 7, 3:03 PM EDTMesoscale DiscussionSPCAlamance, Anson, Bertie, Cabarrus, Caswell, Chatham and 38 more117 min
May 7, 6:10 PM EDTSevere Thunderstorm WatchSPCBeaufort, Bladen, Brunswick, Carteret, Columbus, Craven and 21 more6 hr

Nearby

Mesoscale Discussions in North Carolina, 2009Mesoscale Discussions in Virginia, 2009Mesoscale Discussions in South Carolina, 2009Every mesoscale discussion in 2009

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.