Alert archive / South Carolina / Mesoscale Discussions in 2018

Mesoscale Discussion 1509

September 27, 20184 counties in North Carolina; 8 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at Sep 27, 2018, 7:34 PM EDT for 4 counties in North Carolina; 8 counties in South Carolina. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued: Sep 27, 2018, 7:34 PM EDT (23:34 UTC)
Expired: Sep 27, 2018, 8:30 PM EDT
In force: 56 min
Issued by: the Storm Prediction Center

Counties Cleveland County, NC, Gaston County, NC, Polk County, NC, Rutherford County, NC, Cherokee County, SC, Greenville County, SC, Greenwood County, SC, Laurens County, SC, Newberry County, SC, Spartanburg County, SC, Union County, SC, York County, SC

The radar

The Greer radar (KGSP), 42 km from the middle of the area, began a volume at 23:37 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, 11.6 hours before the alert went out and 208 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: 363 J/kg
Mixed-layer CIN: -31 J/kg
Mixed-layer LCL: 616 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 39 m²/s²
0-3 km storm-relative helicity: 73 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 27, 2:20 PM EDT	Mesoscale Discussion	SPC	Alamance, Anson, Cabarrus, Chatham, Cumberland, Davidson and 16 more	2 hr
Sep 27, 5:47 PM EDT	Mesoscale Discussion	SPC	Alamance, Anson, Chatham, Cumberland, Durham, Franklin and 17 more	88 min
Sep 27, 6:06 PM EDT	Severe Thunderstorm Watch	SPC	Alexander, Cabarrus, Catawba, Cleveland, Davie, Gaston and 6 more	4 hr
Sep 27, 5:34 PM EDT	Mesoscale Discussion	SPC	Abbeville, Anderson, Chester, Edgefield, Fairfield, Greenwood and 5 more	116 min

Nearby

Mesoscale Discussions in South Carolina, 2018 Mesoscale Discussions in North Carolina, 2018 Every mesoscale discussion in 2018

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.