Alert archive / Virginia / Mesoscale Discussions in 2020

Mesoscale Discussion 49

January 11, 20204 states

The Storm Prediction Center issued this mesoscale discussion at Jan 11, 2020, 10:59 PM EST for 4 states. It was in force for 91 min.

The area

The outline as issued.

The facts

Issued
Jan 11, 2020, 10:59 PM EST (03:59 UTC)
Expired
Jan 12, 2020, 12:30 AM EST
In force
91 min
Issued by
the Storm Prediction Center
All 83 counties

Richmond County, GA, Alamance County, NC, Anson County, NC, Caswell County, NC, Chatham County, NC, Cumberland County, NC, Davidson County, NC, Durham County, NC, Franklin County, NC, Granville County, NC, Guilford County, NC, Harnett County, NC, Hoke County, NC, Johnston County, NC, Lee County, NC, Montgomery County, NC, Moore County, NC, Nash County, NC, Orange County, NC, Person County, NC, Randolph County, NC, Richmond County, NC, Robeson County, NC, Rockingham County, NC, Scotland County, NC, Stanly County, NC, Vance County, NC, Wake County, NC, Warren County, NC, Aiken County, SC, Bamberg County, SC, Barnwell County, SC, Calhoun County, SC, Chesterfield County, SC, Clarendon County, SC, Darlington County, SC, Dillon County, SC, Florence County, SC, Kershaw County, SC, Lee County, SC, Lexington County, SC, Marlboro County, SC, Orangeburg County, SC, Richland County, SC, Sumter 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, 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 Lexington, VA, City of Lynchburg, VA, City of Martinsville, VA, City of Petersburg, VA, City of Richmond, VA, Cumberland County, VA, Dinwiddie County, VA, Fluvanna County, VA, Goochland County, VA, Greensville County, VA, Halifax County, VA, Hanover County, VA, Henry County, VA, Louisa County, VA, Lunenburg County, VA, Mecklenburg County, VA, Nelson County, VA, Nottoway County, VA, Orange County, VA, Pittsylvania County, VA, Powhatan County, VA, Prince Edward County, VA, Spotsylvania County, VA

The radar

The Raleigh/Durham radar (KRAX), 110 km from the middle of the area, began a volume at 03:58 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 00:00Z, 4.0 hours before the alert went out and 31 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 00:00Z on 2020-01-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 16 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 00:00Z on 2020-01-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 426 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
16 J/kg
Mixed-layer CIN
-83 J/kg
Mixed-layer LCL
734 m above ground
0-6 km bulk shear
59 kt
0-1 km storm-relative helicity
426 m²/s²
0-3 km storm-relative helicity
489 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

459 
ACUS11 KWNS 120359
SWOMCD
SPC MCD 120359 
VAZ000-NCZ000-SCZ000-GAZ000-120530-

Mesoscale Discussion 0049
NWS Storm Prediction Center Norman OK
0959 PM CST Sat Jan 11 2020

Areas affected...central VA/NC/SC

Concerning...Severe Thunderstorm Watch 18...19...

Valid 120359Z - 120530Z

The severe weather threat for Severe Thunderstorm Watch 18, 19
continues.

SUMMARY...Sporadic strong, damaging wind gusts continue across WW 18
and 19.

DISCUSSION...A segmented squall line continues to track
east/northeast into the VA/NC/SC Piedmont vicinity. Sporadic reports
of wind damage and gusts to around 45 kt have been received over the
last 1-2 hours as portions of the line continue to maintain
organization. While nocturnal stabilization of the low levels may be
inhibiting more widespread severe, temperatures and dewpoints are
holding steady in the mid to upper 60s ahead of the line.  This is
resulting in a few hundred J/kg MLCAPE in conjunction with intense
vertical shear. As such, damaging winds will continue to be possible
with eastward extent over the next few hours. Some severe threat
could extend east of WW 18 into central/eastern VA and a downstream
watch will be considered based on short-term trends.

..Leitman.. 01/12/2020

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...AKQ...LWX...RAH...ILM...RNK...CHS...CAE...GSP...

LAT...LON   37937912 38347809 38127742 37677729 36907739 35787807
            33318026 33158116 33308225 34098121 34558073 35148040
            35718034 36248018 37017985 37557969 37767956 37937912

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jan 11, 8:40 PM ESTMesoscale DiscussionSPCBaker, Ben Hill, Berrien, Bleckley, Burke, Candler and 35 more95 min
Jan 11, 7:37 PM ESTSevere Thunderstorm WatchSPCAlleghany, Ashe, Caswell, Rockingham, Stokes, Surry and 3 more5 hr
Jan 11, 9:35 PM ESTSevere Thunderstorm WatchSPCAlamance, Anson, Bladen, Chatham, Cumberland, Davidson and 19 more4 hr
Jan 11, 11:25 PM ESTSevere Thunderstorm WatchSPCBertie, Camden, Chowan, Edgecombe, Gates, Greene and 13 more4 hr
Jan 12, 1:49 AM ESTMesoscale DiscussionSPCBeaufort, Bladen, Brunswick, Columbus, Craven, Duplin and 10 more86 min

Nearby

Mesoscale Discussions in Virginia, 2020Mesoscale Discussions in North Carolina, 2020Mesoscale Discussions in South Carolina, 2020Every mesoscale discussion in 2020

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.