Alert archive / Virginia / Mesoscale Discussions in 2012

Mesoscale Discussion 1935

September 8, 20124 states

The Storm Prediction Center issued this mesoscale discussion at Sep 8, 2012, 3:25 PM EDT for 4 states. It was in force for 65 min.

The area

The outline as issued.

The facts

Issued
Sep 8, 2012, 3:25 PM EDT (19:25 UTC)
Expired
Sep 8, 2012, 4:30 PM EDT
In force
65 min
Issued by
the Storm Prediction Center
All 108 counties

Saint Mary's County, MD, Somerset County, MD, Alamance County, NC, Alexander County, NC, Cabarrus County, NC, Caswell County, NC, Catawba County, NC, Chatham County, NC, Cleveland County, NC, Cumberland County, NC, Davidson County, NC, Davie County, NC, Durham County, NC, Forsyth County, NC, Franklin County, NC, Gaston County, NC, Granville County, NC, Guilford County, NC, Halifax County, NC, Harnett County, NC, Iredell County, NC, Johnston County, NC, Lee County, NC, Lincoln County, NC, Mecklenburg 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, Yadkin County, NC, Cherokee County, SC, Albemarle County, VA, Amelia County, VA, Amherst County, VA, Appomattox County, VA, Augusta County, VA, Bedford County, VA, Brunswick County, VA, Buckingham County, VA, Campbell County, VA, Caroline County, VA, Charles City County, VA, Charlotte County, VA, Chesterfield County, VA, City of Buena Vista, VA, City of Charlottesville, VA, City of Colonial Heights, VA, City of Danville, VA, City of Emporia, VA, City of Hopewell, VA, City of Lexington, VA, City of Lynchburg, VA, City of Martinsville, VA, City of Petersburg, VA, City of Richmond, VA, City of Roanoke, VA, City of Staunton, VA, City of Waynesboro, VA, City of Williamsburg, VA, Cumberland County, VA, Dinwiddie County, VA, Essex County, VA, Fluvanna County, VA, Franklin County, VA, Gloucester County, VA, Goochland County, VA, Greensville County, VA, Halifax County, VA, Hanover County, VA, Henrico County, VA, Henry County, VA, James City County, VA, King and Queen County, VA, King George County, VA, King William County, VA, Lancaster County, VA, Louisa County, VA, Lunenburg County, VA, Mecklenburg County, VA, Middlesex County, VA, Nelson County, VA, New Kent County, VA, Northumberland County, VA, Nottoway County, VA, Orange County, VA, Patrick County, VA, Pittsylvania County, VA, Powhatan County, VA, Prince Edward County, VA, Prince George County, VA, Richmond County, VA, Rockbridge County, VA, Southampton County, VA, Spotsylvania County, VA, Surry County, VA, Sussex County, VA, Westmoreland County, VA

The radar

The Roanoke radar (KFCX), 121 km from the middle of the area, began a volume at 19:27 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, 7.4 hours before the alert went out and 134 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 2012-09-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 305 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 2012-09-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 68 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
305 J/kg
Mixed-layer CIN
-62 J/kg
Mixed-layer LCL
814 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
68 m²/s²
0-3 km storm-relative helicity
44 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 8, 5:00 AM EDTMesoscale DiscussionSPCAllegany, Garrett60 min
Sep 8, 11:38 AM EDTMesoscale DiscussionSPCAllegany, Baltimore, Carroll, Frederick, Howard, Montgomery and 2 more97 min
Sep 8, 12:15 PM EDTSevere Thunderstorm WatchSPCAllegany, Anne Arundel, Baltimore, Calvert, Caroline, Carroll and 13 more9 hr
Sep 8, 1:48 PM EDTSevere Thunderstorm WatchSPCDorchester, Somerset, Wicomico, Worcester7 hr
Sep 8, 2:12 PM EDTMesoscale DiscussionSPCAnne Arundel, Baltimore, Calvert, Caroline, Carroll, Cecil and 9 more93 min
Sep 8, 4:22 PM EDTMesoscale DiscussionSPCAnne Arundel, Calvert, Caroline, Cecil, Charles, Dorchester and 6 more53 min
Sep 8, 12:20 PM EDTMesoscale DiscussionSPCAlamance, Alexander, Alleghany, Caswell, Davidson, Davie and 10 more115 min
Sep 8, 1:14 PM EDTMesoscale DiscussionSPCCabarrus, Catawba, Cleveland, Gaston, Iredell, Lincoln and 6 more2 hr
Sep 8, 7:10 PM EDTMesoscale DiscussionSPCBeaufort, Bertie, Bladen, Chowan, Craven, Cumberland and 23 more65 min

Nearby

Mesoscale Discussions in Virginia, 2012Mesoscale Discussions in North Carolina, 2012Mesoscale Discussions in Maryland, 2012Every mesoscale discussion in 2012

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.