Alert archive / Virginia / Mesoscale Discussions in 2008

Mesoscale Discussion 2239

September 9, 200847 counties in North Carolina; 56 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Sep 9, 2008, 1:41 PM EDT for 47 counties in North Carolina; 56 counties in Virginia. It was in force for 64 min.

The area

The outline as issued.

The facts

Issued
Sep 9, 2008, 1:41 PM EDT (17:41 UTC)
Expired
Sep 9, 2008, 2:45 PM EDT
In force
64 min
Issued by
the Storm Prediction Center
All 103 counties

Alamance County, NC, Alexander County, NC, Alleghany County, NC, Ashe County, NC, Bertie County, NC, Burke County, NC, Cabarrus County, NC, Caldwell County, NC, Caswell County, NC, Catawba County, NC, Chatham County, NC, Davidson County, NC, Davie County, NC, Durham County, NC, Edgecombe County, NC, Forsyth County, NC, Franklin County, NC, Gates County, NC, Granville County, NC, Guilford County, NC, Halifax County, NC, Harnett County, NC, Hertford County, NC, Iredell County, NC, Johnston County, NC, Lee County, NC, Lincoln County, NC, McDowell County, NC, Montgomery County, NC, Moore County, NC, Nash County, NC, Northampton County, NC, Orange County, NC, Person County, NC, Randolph County, NC, Rockingham County, NC, Rowan County, NC, Stanly County, NC, Stokes County, NC, Surry County, NC, Vance County, NC, Wake County, NC, Warren County, NC, Wayne County, NC, Wilkes County, NC, Wilson County, NC, Yadkin County, NC, Amelia County, VA, Appomattox County, VA, Bedford County, VA, Brunswick County, VA, Buckingham County, VA, Campbell County, VA, Carroll County, VA, Charles City County, VA, Charlotte County, VA, Chesterfield County, VA, City of Colonial Heights, VA, City of Danville, VA, City of Emporia, VA, City of Franklin, VA, City of Galax, VA, City of Hopewell, VA, City of Lynchburg, VA, City of Martinsville, VA, City of Newport News, VA, City of Petersburg, VA, City of Richmond, VA, City of Suffolk, VA, City of Williamsburg, VA, Cumberland County, VA, Dinwiddie County, VA, Floyd County, VA, Franklin County, VA, Gloucester County, VA, Goochland County, VA, Grayson County, VA, Greensville County, VA, Halifax County, VA, Hanover County, VA, Henrico County, VA, Henry County, VA, Isle of Wight County, VA, James City County, VA, King and Queen County, VA, King William County, VA, Lancaster County, VA, Lunenburg County, VA, Mecklenburg County, VA, Middlesex County, VA, New Kent County, VA, Northumberland County, VA, Nottoway County, VA, Patrick County, VA, Pittsylvania County, VA, Powhatan County, VA, Prince Edward County, VA, Prince George County, VA, Southampton County, VA, Surry County, VA, Sussex County, VA, Wythe County, VA, York County, VA

The radar

The Raleigh/Durham radar (KRAX), 105 km from the middle of the area, began a volume at 17:41 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 5.7 hours before the alert went out and 140 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, Greensboro/Hi Pt, NC at 12:00Z on 2008-09-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 983 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, Greensboro/Hi Pt, NC at 12:00Z on 2008-09-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 31 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
983 J/kg
Mixed-layer CIN
-12 J/kg
Mixed-layer LCL
573 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
31 m²/s²
0-3 km storm-relative helicity
46 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.

IssuedProductOfficeCountiesLasted
Sep 9, 2:05 PM EDTSevere Thunderstorm WatchSPCAlamance, Anson, Bertie, Cabarrus, Camden, Caswell and 49 more6 hr
Sep 9, 4:49 PM EDTMesoscale DiscussionSPCAlamance, Beaufort, Bertie, Cabarrus, Camden, Caswell and 49 more86 min
Sep 9, 8:35 AM EDTMesoscale DiscussionSPCAccomack, Arlington, Caroline, Culpeper, Essex, Fairfax and 23 more115 min
Sep 9, 9:33 AM EDTSevere Thunderstorm WatchSPCArlington, Fairfax, King George, Prince William, Spotsylvania, Stafford and 6 more6 hr

Nearby

Mesoscale Discussions in Virginia, 2008Mesoscale Discussions in North Carolina, 2008Every 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.