Alert archive / North Carolina / Mesoscale Discussions in 2016

Mesoscale Discussion 486

April 28, 201640 counties in North Carolina; 9 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Apr 28, 2016, 7:03 PM EDT for 40 counties in North Carolina; 9 counties in Virginia. It was in force for 87 min.

The area

The outline as issued.

The facts

Issued: Apr 28, 2016, 7:03 PM EDT (23:03 UTC)
Expired: Apr 28, 2016, 8:30 PM EDT
In force: 87 min
Issued by: the Storm Prediction Center

All 49 counties

Alamance County, NC, Beaufort County, NC, Bertie County, NC, Camden County, NC, Caswell County, NC, Chatham County, NC, Chowan County, NC, Craven County, NC, Dare 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, Hyde County, NC, Johnston County, NC, Jones County, NC, Lee County, NC, Lenoir County, NC, Martin County, NC, Nash County, NC, Northampton County, NC, Orange County, NC, Pamlico County, NC, Pasquotank County, NC, Perquimans County, NC, Person County, NC, Pitt County, NC, Randolph County, NC, Tyrrell County, NC, Vance County, NC, Wake County, NC, Warren County, NC, Washington County, NC, Wayne County, NC, Wilson County, NC, Brunswick County, VA, City of Danville, VA, City of Emporia, VA, City of Franklin, VA, City of Suffolk, VA, Greensville County, VA, Halifax County, VA, Mecklenburg County, VA, Southampton County, VA

The radar

The Raleigh/Durham radar (KRAX), 64 km from the middle of the area, began a volume at 23:02 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, 11.1 hours before the alert went out and 141 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: 609 J/kg
Mixed-layer CIN: -41 J/kg
Mixed-layer LCL: 624 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 169 m²/s²
0-3 km storm-relative helicity: 131 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

976 
ACUS11 KWNS 282304
SWOMCD
SPC MCD 282303 
NCZ000-VAZ000-290030-

MESOSCALE DISCUSSION 0486
NWS STORM PREDICTION CENTER NORMAN OK
0603 PM CDT THU APR 28 2016

AREAS AFFECTED...PORTIONS OF EASTERN NC AND SOUTHEASTERN VA

CONCERNING...SEVERE THUNDERSTORM WATCH 119...

VALID 282303Z - 290030Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 119
CONTINUES.

SUMMARY...THE THREAT FOR A FEW DAMAGING WIND GUSTS AND LARGE HAIL
REPORTS WILL PERSIST FOR A FEW MORE HOURS THIS EVENING...GENERALLY
OVER EAST-CENTRAL NC. A SEVERE CELL OR TWO MAY MOVE OUTSIDE THE
EASTERN BOUND OF THE WATCH...BUT THE THREAT WILL BE TOO LIMITED IN
SPACE AND TIME FOR NEW WATCH ISSUANCE.

DISCUSSION...CLUSTERS OF STRONG/SEVERE THUNDERSTORMS CONTINUE ACROSS
PORTIONS OF WW 119 THIS EVENING...WITH MULTIPLE LARGE HAIL REPORTS
NOTED OVER THE LAST SEVERAL HOURS. KRAX VWP AND MESOANALYSIS DATA
SUGGEST AROUND 30-40 KT OF DEEP-LAYER SHEAR IS AVAILABLE FOR SOME
UPDRAFT ORGANIZATION...AND A MIXTURE OF SUPERCELL/MULTICELL MODES
HAS BEEN OBSERVED SO FAR. WHILE THE ONSET OF BOUNDARY-LAYER
STABILIZATION THIS EVENING WILL GRADUALLY REDUCE THE HAIL/WIND
THREAT OVER THE NEXT SEVERAL HOURS...SOME THREAT WILL PERSIST ACROSS
SOUTHEASTERN PORTIONS OF THE WATCH.

OVERALL STORM MOTION SHOULD BE GENERALLY EASTWARD...MODULATED
LOCALLY BY PROPAGATION FROM MERGING COLD POOLS/UPSCALE GROWTH AND/OR
NON-LINEAR EFFECTS IN SPLITTING CELLS. SATELLITE AND SURFACE
OBSERVATIONS INDICATE A NARROWING WEDGE OF REMAINING SURFACE
BUOYANCY WITH EASTWARD EXTENT THOUGH...DUE TO A SEA BREEZE OVER
SOUTHEASTERN NC AND A SFC FRONT OVER NORTHERN NC. THEREFORE...THE
LIMITED SPATIAL EXTENT OF THE THREAT SHOULD PRECLUDE NEW WATCH
ISSUANCE EAST OF WW 119.

..PICCA.. 04/28/2016

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

ATTN...WFO...AKQ...MHX...RAH...RNK...

LAT...LON   35877983 36937921 36907698 36587632 35777566 35437567
            35007634 34987783 35037828 35467982 35877983

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 28, 3:56 PM EDT	Mesoscale Discussion	SPC	Alamance, Alleghany, Ashe, Caswell, Chatham, Davidson and 14 more	64 min
Apr 28, 4:21 PM EDT	Severe Thunderstorm Watch	SPC	Alamance, Alexander, Alleghany, Ashe, Burke, Caldwell and 32 more	7 hr

Nearby

Mesoscale Discussions in North Carolina, 2016 Mesoscale Discussions in Virginia, 2016 Every 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.