Alert archive / North Carolina / Mesoscale Discussions in 2017

Mesoscale Discussion 892

May 28, 201715 counties in North Carolina

The Storm Prediction Center issued this mesoscale discussion at May 28, 2017, 2:17 AM EDT for 15 counties in North Carolina. It was in force for 58 min.

The area

The outline as issued.

The facts

Issued: May 28, 2017, 2:17 AM EDT (06:17 UTC)
Expired: May 28, 2017, 3:15 AM EDT
In force: 58 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

Counties Cabarrus County, NC, Chatham County, NC, Davidson County, NC, Davie County, NC, Harnett County, NC, Hoke County, NC, Iredell County, NC, Lee County, NC, Mecklenburg County, NC, Montgomery County, NC, Moore County, NC, Randolph County, NC, Richmond County, NC, Rowan County, NC, Stanly County, NC

The radar

The Raleigh/Durham radar (KRAX), 139 km from the middle of the area, began a volume at 06:18 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 00:00Z, 6.3 hours before the alert went out and 60 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: 1002 J/kg
Mixed-layer CIN: -6 J/kg
Mixed-layer LCL: 1611 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 28 m²/s²
0-3 km storm-relative helicity: 28 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.1

Open this sounding in Storm Lab

The text

As transmitted.

449 
ACUS11 KWNS 280618
SWOMCD
SPC MCD 280617 
NCZ000-SCZ000-280715-

Mesoscale Discussion 0892
NWS Storm Prediction Center Norman OK
0117 AM CDT Sun May 28 2017

Areas affected...central NC

Concerning...Severe potential...Watch possible 

Valid 280617Z - 280715Z

Probability of Watch Issuance...40 percent

SUMMARY...The risk for isolated 50-60 mph gusts with a thunderstorm
cluster within the remnants of a long-lived squall line may continue
east of severe thunderstorm watch 288.  It appears the need for an
additional watch is relatively low given the concentrated/isolated
nature of the overall threat.

DISCUSSION...Radar imagery shows a strong to locally severe
thunderstorm cluster over west-central NC with a MCV located near
the VA/NC/TN border.  The larger-scale convective complex will
continue to move east aided by unidirectional westerly flow and 50
kt at 500 mb per KRAX VAD data.  A corridor of modestly steep
700-500 mb lapse rates still resides across central NC and will
likely assist in storm sustenance despite gradual cooling of the
boundary layer.  Surface analysis indicates low to middle 60s
degrees F dewpoints are in the Piedmont whereas farther east towards
the I-95 corridor slightly richer moisture resides (upper 60s).  It
remains unclear how far east a wind-damage risk will occur. 
Convective trends will be monitored.

..Smith/Edwards.. 05/28/2017

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

ATTN...WFO...RAH...ILM...GSP...

LAT...LON   36028108 35957907 35337858 34827915 35168114 36028108

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 27, 9:00 PM EDT	Mesoscale Discussion	SPC	Beaufort, Bertie, Camden, Chowan, Dare, Edgecombe and 11 more	30 min
May 27, 10:46 PM EDT	Mesoscale Discussion	SPC	Alexander, Alleghany, Ashe, Avery, Buncombe, Burke and 33 more	89 min
May 28, 12:13 AM EDT	Severe Thunderstorm Watch	SPC	Union	3 hr
May 28, 2:27 PM EDT	Mesoscale Discussion	SPC	Bertie, Camden, Chowan, Currituck, Gates, Hertford and 5 more	63 min
May 28, 4:56 PM EDT	Mesoscale Discussion	SPC	Bladen, Brunswick, Columbus, Robeson	2 hr
May 28, 7:06 PM EDT	Severe Thunderstorm Watch	SPC	Bladen, Brunswick, Columbus, New Hanover, Pender, Robeson	4 hr

Nearby

Mesoscale Discussions in North Carolina, 2017 Every mesoscale discussion in 2017

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.