Alert archive / South Carolina / Mesoscale Discussions in 2017

Mesoscale Discussion 910

May 28, 20175 counties in North Carolina; 14 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at May 28, 2017, 8:20 PM EDT for 5 counties in North Carolina; 14 counties in South Carolina. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued: May 28, 2017, 8:20 PM EDT (00:20 UTC)
Expired: May 28, 2017, 9:45 PM EDT
In force: 85 min
Issued by: the Storm Prediction Center

Counties Bladen County, NC, Brunswick County, NC, Columbus County, NC, New Hanover County, NC, Pender County, NC, Bamberg County, SC, Berkeley County, SC, Calhoun County, SC, Charleston County, SC, Clarendon County, SC, Dillon County, SC, Dorchester County, SC, Florence County, SC, Georgetown County, SC, Horry County, SC, Marion County, SC, Orangeburg County, SC, Sumter County, SC, Williamsburg County, SC

The radar

The Wilmington radar (KLTX), 115 km from the middle of the area, began a volume at 00:24 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

Charleston AFB, SC (KCHS), launched 00:00Z, 0.3 hours before the alert went out and 89 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: 1857 J/kg
Mixed-layer CIN: -54 J/kg
Mixed-layer LCL: 1157 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 152 m²/s²
0-3 km storm-relative helicity: 213 m²/s²
Significant tornado parameter: 0.9
Supercell composite: 12.4

Open this sounding in Storm Lab

The text

As transmitted.

782 
ACUS11 KWNS 290020
SWOMCD
SPC MCD 290020 
NCZ000-SCZ000-290145-

Mesoscale Discussion 0910
NWS Storm Prediction Center Norman OK
0720 PM CDT Sun May 28 2017

Areas affected...Central/eastern SC...Southeast NC

Concerning...Severe Thunderstorm Watch 295...

Valid 290020Z - 290145Z

The severe weather threat for Severe Thunderstorm Watch 295
continues.

SUMMARY...A corridor of damaging wind appears possible ahead of
evolving convective line across central/eastern SC. Isolated
instances of large hail are possible as well.

DISCUSSION...A small QLCS has evolved across central into northeast
SC, with more isolated strong to locally severe cells south of
Columbia, SC and west of Wilmington, NC. The 00Z CHS sounding
depicts moderate-to-strong instability, steep midlevel lapse rates,
and relatively strong westerly mid-level flow. This environment will
favor the potential for a corridor of damaging wind associated with
the small QLCS that will move into northeast SC and southeast NC in
the next 1-2 hours. The other isolated cells across WW 295 will also
be capable of producing localized damaging wind, along with some
hail potential as well.

..Dean.. 05/29/2017

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

ATTN...WFO...MHX...RAH...ILM...CHS...CAE...

LAT...LON   33518134 33818111 34098040 34407946 34597888 34747816
            34647763 34407747 33917773 33247880 32857921 32627948
            32537973 32588017 33018090 33308136 33518134

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 29, 3:15 PM EDT	Severe Thunderstorm Watch	SPC	Cabarrus, Cleveland, Gaston, Lincoln, Mecklenburg, Union	7 hr
May 29, 4:59 PM EDT	Mesoscale Discussion	SPC	Cabarrus, Cleveland, Gaston, Lincoln, Mecklenburg, Union	2 hr
May 29, 7:30 PM EDT	Mesoscale Discussion	SPC	Cabarrus, Mecklenburg, Union	60 min
May 29, 2:27 PM EDT	Mesoscale Discussion	SPC	Abbeville, Aiken, Allendale, Bamberg, Barnwell, Calhoun and 6 more	3 hr

Nearby

Mesoscale Discussions in South Carolina, 2017 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.