Alert archive / Virginia / Mesoscale Discussions in 2016

Mesoscale Discussion 1738

September 28, 201611 counties in North Carolina; 50 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Sep 28, 2016, 12:09 PM EDT for 11 counties in North Carolina; 50 counties in Virginia. It was in force for 66 min.

The area

The outline as issued.

The facts

Issued
Sep 28, 2016, 12:09 PM EDT (16:09 UTC)
Expired
Sep 28, 2016, 1:15 PM EDT
In force
66 min
Issued by
the Storm Prediction Center
Chance of a watch
60%
All 61 counties

Caswell County, NC, Durham County, NC, Franklin County, NC, Granville County, NC, Halifax County, NC, Nash County, NC, Northampton County, NC, Orange County, NC, Person County, NC, Vance County, NC, Warren County, NC, Amelia County, VA, Appomattox 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 Colonial Heights, VA, City of Danville, VA, City of Emporia, VA, City of Franklin, VA, City of Hopewell, VA, City of Petersburg, VA, City of Richmond, VA, City of Williamsburg, VA, Cumberland County, VA, Dinwiddie County, VA, Essex County, VA, Fluvanna County, VA, Gloucester County, VA, Goochland County, VA, Greensville County, VA, Halifax County, VA, Hanover County, VA, Henrico 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, Mecklenburg County, VA, Middlesex County, VA, New Kent County, VA, Northumberland County, VA, Nottoway 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

The radar

The Norfolk radar (KAKQ), 81 km from the middle of the area, began a volume at 16:11 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

Roanoke, VA (KRNK), launched 12:00Z, 4.2 hours before the alert went out and 142 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, 2:44 PM EDTMesoscale DiscussionSPCAlamance, Caswell, Chatham, Davidson, Davie, Durham and 24 more91 min
Sep 28, 3:13 PM EDTSevere Thunderstorm WatchSPCAlamance, Alexander, Alleghany, Anson, Ashe, Avery and 52 more7 hr
Sep 28, 4:41 PM EDTMesoscale DiscussionSPCAlamance, Alexander, Alleghany, Anson, Ashe, Avery and 56 more2 hr
Sep 28, 7:02 PM EDTMesoscale DiscussionSPCAlamance, Alexander, Alleghany, Ashe, Cabarrus, Caldwell and 32 more88 min

Nearby

Mesoscale Discussions in Virginia, 2016Mesoscale Discussions in North 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.