Alert archive / North Carolina / Mesoscale Discussions in 2009

Mesoscale Discussion 1876

August 12, 20094 states

The Storm Prediction Center issued this mesoscale discussion at Aug 12, 2009, 4:13 PM EDT for 4 states. It was in force for 92 min.

The area

The outline as issued.

The facts

Issued
Aug 12, 2009, 4:13 PM EDT (20:13 UTC)
Expired
Aug 12, 2009, 5:45 PM EDT
In force
92 min
Issued by
the Storm Prediction Center
All 79 counties

Bryan County, GA, Bulloch County, GA, Candler County, GA, Chatham County, GA, Effingham County, GA, Emanuel County, GA, Jenkins County, GA, Screven County, GA, Beaufort County, NC, Bertie County, NC, Bladen County, NC, Brunswick County, NC, Camden County, NC, Chowan County, NC, Columbus County, NC, Craven County, NC, Currituck County, NC, Duplin County, NC, Edgecombe County, NC, Gates County, NC, Greene County, NC, Halifax County, NC, Hertford County, NC, Hyde County, NC, Jones County, NC, Lenoir County, NC, Martin County, NC, Nash 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, Tyrrell County, NC, Warren County, NC, Washington County, NC, Wilson County, NC, Allendale County, SC, Bamberg County, SC, Barnwell County, SC, Beaufort County, SC, Berkeley County, SC, Calhoun County, SC, Charleston County, SC, Clarendon County, SC, Colleton County, SC, Dorchester County, SC, Florence County, SC, Georgetown County, SC, Hampton County, SC, Horry County, SC, Jasper County, SC, Marion County, SC, Orangeburg County, SC, Sumter County, SC, Williamsburg County, SC, Brunswick County, VA, City of Chesapeake, VA, City of Emporia, VA, City of Franklin, VA, City of Hampton, VA, City of Newport News, VA, City of Norfolk, VA, City of Poquoson, VA, City of Portsmouth, VA, City of Suffolk, VA, City of Virginia Beach, VA, City of Williamsburg, VA, Gloucester County, VA, Greensville County, VA, Isle of Wight County, VA, James City County, VA, Southampton County, VA, Surry County, VA, Sussex County, VA, York County, VA

The radar

The Raleigh/Durham radar (KRAX), 79 km from the middle of the area, began a volume at 20:16 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 12:00Z, 8.2 hours before the alert went out and 257 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, Roanoke, VA at 12:00Z on 2009-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 33 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, Roanoke, VA at 12:00Z on 2009-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -53 square meters per square second.1939Sfc1 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
33 J/kg
Mixed-layer CIN
-59 J/kg
Mixed-layer LCL
699 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
-53 m²/s²
0-3 km storm-relative helicity
-84 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
Aug 12, 11:25 AM EDTMesoscale DiscussionSPCAppling, Bacon, Brantley, Bryan, Bulloch, Burke and 21 more2 hr
Aug 12, 12:23 PM EDTSevere Thunderstorm WatchSPCBryan, Bulloch, Candler, Chatham, Effingham, Evans and 6 more9 hr
Aug 12, 1:32 PM EDTMesoscale DiscussionSPCAtkinson, Bacon, Berrien, Brantley, Brooks, Camden and 12 more118 min

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.