Alert archive / Virginia / Mesoscale Discussions in 2016

Mesoscale Discussion 1740

September 28, 20164 states

The Storm Prediction Center issued this mesoscale discussion at Sep 28, 2016, 4:41 PM EDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Sep 28, 2016, 4:41 PM EDT (20:41 UTC)
Expired
Sep 28, 2016, 6:45 PM EDT
In force
2 hr
Issued by
the Storm Prediction Center
All 149 counties

Calvert County, MD, Charles County, MD, Dorchester County, MD, Saint Mary's County, MD, Talbot County, MD, Alamance County, NC, Alexander County, NC, Alleghany County, NC, Anson County, NC, Ashe County, NC, Avery County, NC, Bladen County, NC, Burke County, NC, Cabarrus County, NC, Caldwell 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, Edgecombe County, NC, Forsyth County, NC, Franklin County, NC, Gaston County, NC, Granville County, NC, Greene County, NC, Guilford County, NC, Halifax County, NC, Harnett County, NC, Hertford County, NC, Hoke County, NC, Iredell County, NC, Johnston County, NC, Lee County, NC, Lincoln County, NC, McDowell County, NC, Mecklenburg County, NC, Montgomery County, NC, Moore County, NC, Nash County, NC, Northampton County, NC, Orange County, NC, Person County, NC, Polk County, NC, Randolph County, NC, Richmond County, NC, Robeson County, NC, Rockingham County, NC, Rowan County, NC, Rutherford County, NC, Sampson County, NC, Scotland County, NC, Stanly County, NC, Stokes County, NC, Surry County, NC, Union County, NC, Vance County, NC, Wake County, NC, Warren County, NC, Watauga County, NC, Wayne County, NC, Wilkes County, NC, Wilson County, NC, Yadkin County, NC, Cherokee County, SC, Chester County, SC, Chesterfield County, SC, Darlington County, SC, Kershaw County, SC, Lancaster County, SC, Marlboro County, SC, York County, SC, Albemarle County, VA, Amelia County, VA, Amherst County, VA, Appomattox County, VA, Bedford County, VA, Brunswick County, VA, Buckingham County, VA, Campbell County, VA, Caroline County, VA, Carroll 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 Franklin, VA, City of Fredericksburg, VA, City of Galax, VA, City of Hampton, VA, City of Hopewell, VA, City of Lynchburg, VA, City of Martinsville, VA, City of Newport News, VA, City of Petersburg, VA, City of Poquoson, VA, City of Richmond, VA, City of Roanoke, VA, City of Salem, VA, City of Suffolk, VA, City of Williamsburg, VA, Cumberland County, VA, Dinwiddie County, VA, Essex County, VA, Floyd County, VA, Fluvanna 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 George County, VA, King William County, VA, Lancaster County, VA, Louisa County, VA, Lunenburg County, VA, Mathews County, VA, Mecklenburg County, VA, Middlesex County, VA, Nelson 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, Richmond County, VA, Southampton County, VA, Spotsylvania County, VA, Surry County, VA, Sussex County, VA, Westmoreland County, VA, York County, VA

The radar

The Raleigh/Durham radar (KRAX), 118 km from the middle of the area, began a volume at 20:43 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, 8.7 hours before the alert went out and 83 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 2016-09-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2016-09-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 13 square meters per square second.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2684 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
13 m²/s²
0-3 km storm-relative helicity
19 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 28, 3:13 PM EDTSevere Thunderstorm WatchSPCCalvert, Charles, Saint Mary's7 hr
Sep 28, 7:02 PM EDTMesoscale DiscussionSPCCalvert, Saint Mary's, Talbot88 min
Sep 28, 12:09 PM EDTMesoscale DiscussionSPCCaswell, Durham, Franklin, Granville, Halifax, Nash and 5 more66 min
Sep 28, 2:44 PM EDTMesoscale DiscussionSPCAlamance, Caswell, Chatham, Davidson, Davie, Durham and 24 more91 min

Nearby

Mesoscale Discussions in Virginia, 2016Mesoscale Discussions in North Carolina, 2016Mesoscale Discussions in South Carolina, 2016Every mesoscale discussion in 2016

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.