Alert archive / North Carolina / Mesoscale Discussions in 2011

Mesoscale Discussion 458

April 16, 201155 counties in North Carolina; 19 counties in South Carolina; 49 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Apr 16, 2011, 2:28 PM EDT for 55 counties in North Carolina; 19 counties in South Carolina; 49 counties in Virginia. It was in force for 92 min.

The area

The outline as issued.

The facts

Issued: Apr 16, 2011, 2:28 PM EDT (18:28 UTC)
Expired: Apr 16, 2011, 4:00 PM EDT
In force: 92 min
Issued by: the Storm Prediction Center

All 123 counties

Alamance County, NC, Beaufort County, NC, Bertie County, NC, Bladen County, NC, Brunswick County, NC, Camden County, NC, Carteret County, NC, Caswell County, NC, Chatham County, NC, Chowan County, NC, Columbus County, NC, Craven County, NC, Cumberland County, NC, Currituck County, NC, Dare County, NC, Duplin 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, Hoke County, NC, Hyde County, NC, Johnston County, NC, Jones County, NC, Lee County, NC, Lenoir County, NC, Martin County, NC, Moore County, NC, Nash County, NC, New Hanover County, NC, Northampton County, NC, Onslow County, NC, Orange County, NC, Pamlico County, NC, Pasquotank County, NC, Pender County, NC, Perquimans County, NC, Person County, NC, Pitt County, NC, Richmond County, NC, Robeson County, NC, Sampson County, NC, Scotland County, NC, Tyrrell County, NC, Vance County, NC, Wake County, NC, Warren County, NC, Washington County, NC, Wayne County, NC, Wilson County, NC, Beaufort County, SC, Berkeley County, SC, Calhoun County, SC, Charleston County, SC, Clarendon County, SC, Colleton County, SC, Darlington County, SC, Dillon County, SC, Dorchester County, SC, Florence County, SC, Georgetown County, SC, Horry County, SC, Jasper County, SC, Lee County, SC, Marion County, SC, Marlboro County, SC, Orangeburg County, SC, Sumter County, SC, Williamsburg County, SC, Amelia County, VA, Brunswick County, VA, Charles City County, VA, Charlotte County, VA, Chesterfield County, VA, City of Chesapeake, VA, City of Colonial Heights, VA, City of Danville, 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 Virginia Beach, VA, City of Williamsburg, VA, Cumberland County, VA, Dinwiddie County, VA, Essex 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 William County, VA, Lancaster County, VA, Lunenburg County, VA, Mathews County, VA, Mecklenburg County, VA, Middlesex County, VA, New Kent County, VA, Nottoway County, VA, Powhatan County, VA, Prince Edward County, VA, Prince George County, VA, Richmond County, VA, Southampton County, VA, Surry County, VA, Sussex County, VA, York County, VA

The radar

The Morehead City radar (KMHX), 91 km from the middle of the area, began a volume at 18:30 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

Newport, NC (KMHX), launched 12:00Z, 6.5 hours before the alert went out and 91 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: 7 J/kg
Mixed-layer CIN: -6 J/kg
Mixed-layer LCL: 824 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 201 m²/s²
0-3 km storm-relative helicity: 308 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.

609 
ACUS11 KWNS 161829
SWOMCD
SPC MCD 161828
NCZ000-VAZ000-SCZ000-162000-

MESOSCALE DISCUSSION 0458
NWS STORM PREDICTION CENTER NORMAN OK
0128 PM CDT SAT APR 16 2011

AREAS AFFECTED...PORTIONS S-CENTRAL/SERN VA...CENTRAL/ERN NC...ERN
SC.

CONCERNING...TORNADO WATCH 150...

VALID 161828Z - 162000Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 150 CONTINUES.

THREAT FOR SUPERCELLS AND TORNADOES...SOME WITH POTENTIAL FOR
SIGNIFICANT DAMAGE...CONTINUES OVER WW.

LATEST/18Z SFC MESOANALYSIS SHOWS RAPIDLY DEVELOPING MESOLOW NEAR
ALAMANCE COUNTY ALONG PRIMARY CONVECTIVE BAND...PRECEDED BY SMALL
BUT PRONOUNCED AREA OF BACKED FLOW AND PRESSURE FALLS AT RATE OF 5-8
MB PER 2 HOURS.  RELATED ISALLOBARIC FORCING SHOULD HELP TO
MAINTAIN...AND PERHAPS LOCALLY INCREASE...ALREADY EXPANSIVE
HODOGRAPH SIZE FROM RDU AREA ENEWD AND NEWD ACROSS N-CENTRAL NC INTO
S-CENTRAL VA.  RDU VWP SHOWS 500 J/KG OF 0-1 KM AGL SRH...AND 900
J/KG IN 0-3 KM LAYER...WHICH ALREADY IS EXTREME AND LIKELY
UNDER-REPRESENTS VALUES NEARER TO THE MESOLOW.  0-1 KM SRH NEAR 300
J/KG IS EVIDENT AS FAR S AS ERN SC.  CONTINUED
HEATING/DESTABILIZATION OF AIR MASS OVER THIS REGION...COMBINED WITH
BOUNDARY-LAYER THETAE ADVECTION...WILL JUXTAPOSE CORRIDOR OF
500-1500 J/KG MLCAPE OVER THESE FAVORABLE KINEMATIC PROFILES IN
PRE-STORM SECTOR.

..EDWARDS.. 04/16/2011

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

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

LAT...LON   33428097 35057987 37007935 37997786 37987648 37487610
            36967597 36307580 35717547 35357549 35157553 35207567
            35017608 34657650 34507650 34627661 34627709 34237775
            33677800 33897806 33727884 33177922 32807982 32438044
            32148100 32608114 33428097

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 16, 5:57 AM EDT	Tornado Watch	SPC	Alexander, Cabarrus, Catawba, Cleveland, Davie, Gaston and 9 more	8 hr
Apr 16, 10:39 AM EDT	Mesoscale Discussion	SPC	Alamance, Anson, Bertie, Bladen, Brunswick, Cabarrus and 52 more	2 hr
Apr 16, 12:02 PM EDT	Tornado Watch PDS	SPC	Alamance, Anson, Beaufort, Bertie, Bladen, Brunswick and 60 more	11 hr
Apr 16, 12:16 PM EDT	Mesoscale Discussion	SPC	Beaufort, Bertie, Bladen, Brunswick, Chowan, Columbus and 25 more	59 min
Apr 16, 4:49 PM EDT	Mesoscale Discussion	SPC	Beaufort, Bertie, Bladen, Brunswick, Camden, Carteret and 34 more	86 min
Apr 16, 6:59 PM EDT	Mesoscale Discussion	SPC	Beaufort, Bertie, Bladen, Brunswick, Camden, Carteret and 28 more	91 min
Apr 16, 5:09 AM EDT	Mesoscale Discussion	SPC	Abbeville, Aiken, Anderson, Chester, Edgefield, Fairfield and 10 more	96 min
Apr 16, 12:52 PM EDT	Mesoscale Discussion	SPC	Accomack, Albemarle, Amherst, Arlington, Augusta, Botetourt and 51 more	113 min
Apr 16, 1:29 PM EDT	Tornado Watch	SPC	Albemarle, Arlington, Augusta, Clarke, Culpeper, Fairfax and 28 more	8 hr
Apr 16, 4:29 PM EDT	Mesoscale Discussion	SPC	Arlington, Clarke, Culpeper, Fairfax, Fauquier, Frederick and 20 more	31 min
Apr 16, 6:38 PM EDT	Mesoscale Discussion	SPC	Albemarle, Arlington, Augusta, Clarke, Culpeper, Fairfax and 28 more	97 min

Nearby

Mesoscale Discussions in North Carolina, 2011 Mesoscale Discussions in Virginia, 2011 Mesoscale Discussions in South Carolina, 2011 Every mesoscale discussion in 2011

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.