Alert archive / Virginia / Mesoscale Discussions in 2014

Mesoscale Discussion 182

March 12, 20145 states

The Storm Prediction Center issued this mesoscale discussion at Mar 12, 2014, 7:08 PM EDT for 5 states. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued: Mar 12, 2014, 7:08 PM EDT (23:08 UTC)
Expired: Mar 12, 2014, 8:45 PM EDT
In force: 97 min
Issued by: the Storm Prediction Center

All 80 counties

Kent County, DE, Sussex County, DE, Anne Arundel County, MD, Calvert County, MD, Caroline County, MD, Charles County, MD, City of Baltimore, MD, Dorchester County, MD, Harford County, MD, Kent County, MD, Prince George's County, MD, Queen Anne's County, MD, Saint Mary's County, MD, Somerset County, MD, Talbot County, MD, Wicomico County, MD, Bertie County, NC, Chatham County, NC, Chowan County, NC, Durham County, NC, Edgecombe County, NC, Franklin County, NC, Gates County, NC, Granville County, NC, Greene County, NC, Halifax County, NC, Harnett County, NC, Hertford County, NC, Johnston County, NC, Lee County, NC, Martin County, NC, Nash County, NC, Northampton County, NC, Perquimans County, NC, Vance County, NC, Wake County, NC, Warren County, NC, Wayne County, NC, Wilson County, NC, Cumberland County, NJ, Accomack County, VA, Brunswick County, VA, Charles City County, VA, Chesterfield County, VA, City of Chesapeake, VA, City of Colonial Heights, VA, City of Emporia, VA, City of Franklin, VA, City of Hampton, VA, City of Hopewell, VA, City of Newport News, VA, City of Norfolk, VA, City of Petersburg, VA, City of Poquoson, VA, City of Portsmouth, VA, City of Richmond, VA, City of Suffolk, VA, City of Williamsburg, VA, Dinwiddie County, VA, Essex County, VA, Gloucester County, VA, Greensville 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, Mathews County, VA, Middlesex County, VA, New Kent County, VA, Northumberland County, VA, Prince George County, VA, Richmond County, VA, Southampton County, VA, Surry County, VA, Sussex County, VA, Westmoreland County, VA, York County, VA

The radar

The Norfolk radar (KAKQ), 43 km from the middle of the area, began a volume at 23:07 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

Wallops Is Stn, VA (KWAL), launched 12:00Z, 11.1 hours before the alert went out and 173 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 2621 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 71 m²/s²
0-3 km storm-relative helicity: 124 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.

647 
ACUS11 KWNS 122309
SWOMCD
SPC MCD 122308 
NJZ000-MDZ000-DEZ000-VAZ000-NCZ000-DCZ000-130045-

MESOSCALE DISCUSSION 0182
NWS STORM PREDICTION CENTER NORMAN OK
0608 PM CDT WED MAR 12 2014

AREAS AFFECTED...PORTIONS OF VA/NC AND EASTERN MD TO DE/SOUTHERN NJ

CONCERNING...SEVERE THUNDERSTORM WATCH 28...

VALID 122308Z - 130045Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 28
CONTINUES.

SUMMARY...SEVERE THUNDERSTORM WATCH 28 CONTINUES UNTIL 02Z /10PM
EDT/. AS A LINE OF CONVECTION SPREADS EASTWARD THIS
EVENING...DAMAGING WINDS REMAIN A POSSIBILITY ACROSS THE NC
PIEDMONT/NORTHEAST NC AND EASTERN VA/MD...ALONG WITH DE/SOUTHERN NJ.

DISCUSSION...A RELATIVELY WELL-ORGANIZED LINE OF CONVECTION WILL
CONTINUE TO MAKE A STEADY EASTWARD PROGRESSION ACROSS EASTERN
PORTIONS OF NC/VA/MD INTO DE/SOUTHERN NJ...WITH PARTICULARLY
WELL-ORGANIZED STRUCTURES INCLUDING EMBEDDED BOWS/LEWP ORGANIZATION
AND CLOUD-GROUND LIGHTNING ACROSS THE NORTH-CENTRAL NC PIEDMONT/FAR
SOUTH-CENTRAL VA AS OF 2300Z. A 53 KT WIND GUST WAS MEASURED AT
GREENSBORO NC EARLIER /AROUND 2121Z/ WITH THIS CONVECTION. 

CONVECTIVE LINE-PRECEDING INSTABILITY WILL REMAIN QUITE
MARGINAL...ESPECIALLY WITH NORTHWARD EXTENT NEAR THE STEADILY
DEEPENING SURFACE LOW ACROSS SOUTHEAST PA AND NJ AND THE STRONG
PRIMARY PRESSURE FALL-RISE COUPLET. REGARDLESS...60S F SURFACE
TEMPERATURES AND MIDDLE 50S F SURFACE DEWPOINTS WILL REMAIN ADEQUATE
FOR AN ISOLATED DAMAGING WIND RISK...EVEN IN THE RELATIVE ABSENCE OF
CLOUD-GROUND LIGHTNING...GIVEN THE STRENGTH OF THE DEEP-LAYER WIND
FIELD. THIS IS ESPECIALLY THE CASE WITH AS MUCH AS 40-50 KT WINDS
WITHIN THE LOWEST 2-3 KM PER REGIONAL WSR-88D VWP DATA.

..GUYER.. 03/12/2014

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...PHI...AKQ...MHX...LWX...RAH...

LAT...LON   35597963 36467853 37547754 38957695 39597646 39457497
            38757494 37497597 36087637 35177831 35597963

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 12, 4:58 PM EDT	Severe Thunderstorm Watch	SPC	Kent, New Castle, Sussex	5 hr
Mar 12, 11:43 AM EDT	Mesoscale Discussion	SPC	Allegany, Garrett	3 hr
Mar 12, 4:21 PM EDT	Mesoscale Discussion	SPC	Anne Arundel, Baltimore, Calvert, Caroline, Carroll, Cecil and 12 more	114 min

Nearby

Mesoscale Discussions in Virginia, 2014 Mesoscale Discussions in North Carolina, 2014 Mesoscale Discussions in Maryland, 2014 Every mesoscale discussion in 2014

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.