Alert archive / North Carolina / Mesoscale Discussions in 2011

Mesoscale Discussion 1502

July 4, 20114 states

The Storm Prediction Center issued this mesoscale discussion at Jul 4, 2011, 6:44 PM EDT for 4 states. It was in force for 61 min.

The area

The outline as issued.

The facts

Issued: Jul 4, 2011, 6:44 PM EDT (22:44 UTC)
Expired: Jul 4, 2011, 7:45 PM EDT
In force: 61 min
Issued by: the Storm Prediction Center

All 105 counties

Saint Mary's County, MD, Alamance County, NC, Anson County, NC, Beaufort County, NC, Bertie County, NC, Bladen County, NC, Camden County, NC, Chatham County, NC, Chowan County, NC, Craven County, NC, Cumberland County, NC, Currituck County, NC, Duplin County, NC, Durham County, NC, Edgecombe County, NC, Franklin County, NC, Gates County, NC, Greene County, NC, Halifax County, NC, Harnett County, NC, Hertford County, NC, Hoke County, NC, Johnston County, NC, Jones County, NC, Lee County, NC, Lenoir County, NC, Martin County, NC, Montgomery County, NC, Moore County, NC, Nash County, NC, Northampton County, NC, Orange County, NC, Pasquotank County, NC, Perquimans County, NC, Pitt County, NC, Randolph County, NC, Richmond County, NC, Robeson County, NC, Sampson County, NC, Scotland County, NC, Stanly County, NC, Tyrrell County, NC, Union County, NC, Wake County, NC, Warren County, NC, Washington County, NC, Wayne County, NC, Wilson County, NC, Calhoun County, SC, Chester County, SC, Chesterfield County, SC, Darlington County, SC, Dillon County, SC, Fairfield County, SC, Kershaw County, SC, Lancaster County, SC, Lee County, SC, Lexington County, SC, Marlboro County, SC, Newberry County, SC, Richland County, SC, Sumter County, SC, Accomack County, VA, Caroline 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 Virginia Beach, VA, City of Williamsburg, VA, Essex County, VA, Gloucester County, VA, Goochland County, VA, Greensville 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, Mathews County, VA, Middlesex County, VA, New Kent County, VA, Northampton County, VA, Northumberland County, VA, Powhatan 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 Raleigh/Durham radar (KRAX), 29 km from the middle of the area, began a volume at 22:43 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

Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 10.7 hours before the alert went out and 106 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: 880 J/kg
Mixed-layer CIN: -120 J/kg
Mixed-layer LCL: 1130 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: 22 m²/s²
0-3 km storm-relative helicity: 32 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.

727 
ACUS11 KWNS 042245
SWOMCD
SPC MCD 042244
VAZ000-MDZ000-NCZ000-SCZ000-042345-

MESOSCALE DISCUSSION 1502
NWS STORM PREDICTION CENTER NORMAN OK
0544 PM CDT MON JUL 04 2011

AREAS AFFECTED...CAROLINA PIEDMONT / SERN VA

CONCERNING...SEVERE THUNDERSTORM WATCH 594...595...

VALID 042244Z - 042345Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH
594...595...CONTINUES.

SPORADIC POCKETS OF WIND DAMAGE WILL PERSIST INTO THE EVENING HOURS
ACROSS THE CAROLINA PIEDMONT AND SERN VA.  LOOSE LINEAR CONGLOMERATE
OF STORMS ACROSS THIS REGION WILL CONTINUE TO MOVE EWD BEFORE
CONVECTIVE OVERTURNING THEREBY NEGATES A STRONG TSTM /DMGG WIND/
THREAT.

22Z SURFACE/RADAR MOSAIC ANALYSIS SHOWS 1+ MB/HR RISES IN WAKE OF A
LOOSE CONGLOMERATE OF STORMS ACROSS THE CAROLINA PIEDMONT AND
S-CNTRL VA FROM RIC TO THE UPSTATE OF SC.  THERE WAS A RECENT
MEASURED GUST OF 43 KTS AT KSFQ /SUFFOLK VA/.  STRONG SURFACE
HEATING E OF THE LINEAR STORM CLUSTER HAS RESULTED IN TEMPS RISING
WELL INTO THE 90S IN MOST LOCATIONS WITH SURFACE T/TD SPREADS AROUND
30 DEG F AND A STEEP LOW LEVEL LAPSE RATE ENVIRONMENT.  KRAX VAD
SHOWS WEAK WLY TROPOSPHERIC FLOW FAVORING AN EWD STORM MOTION OF
AROUND 15 KTS.  THE CONSOLIDATED EWD MOVING COLD POOL WITH THE
LINEAR STORM CONGLOMERATE WILL LIKELY CONTINUE TO POSE A
STRONG-PERHAPS SEVERE DOWNDRAFT RISK...WITH POCKETS OF SPORADIC WIND
DAMAGE THE RESULT.  AS SUCH...A LOCAL EXTENSION-IN-AREA MAY BE
WARRANTED FOR PORTIONS OF THE NC PIEDMONT/COASTAL PLAIN OR A NEW WW
MAY BE CONSIDERED.

..SMITH.. 07/04/2011

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

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

LAT...LON   34178178 35218080 36187930 36417805 37127757 37657829
            38317666 37767543 36367567 35247667 34377911 33668060
            33648151 34178178

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 3, 8:41 PM EDT	Mesoscale Discussion	SPC	Calvert, Caroline, Charles, Dorchester, Saint Mary's, Somerset and 2 more	64 min
Jul 4, 1:54 PM EDT	Mesoscale Discussion	SPC	Allegany, Garrett	96 min
Jul 4, 2:34 PM EDT	Severe Thunderstorm Watch	SPC	Calvert, Charles, Dorchester, Saint Mary's, Somerset, Wicomico and 1 more	6 hr
Jul 4, 12:10 PM EDT	Mesoscale Discussion	SPC	Alleghany, Ashe, Avery, Caldwell, Caswell, Madison and 8 more	95 min
Jul 4, 12:50 PM EDT	Severe Thunderstorm Watch	SPC	Alamance, Alexander, Alleghany, Anson, Ashe, Avery and 41 more	7 hr

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.