Alert archive / South Carolina / Mesoscale Discussions in 2020

Mesoscale Discussion 1739

October 11, 202011 counties in North Carolina; 13 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at Oct 11, 2020, 1:31 PM EDT for 11 counties in North Carolina; 13 counties in South Carolina. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: Oct 11, 2020, 1:31 PM EDT (17:31 UTC)
Expired: Oct 11, 2020, 4:30 PM EDT
In force: 3 hr
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch unlikely
Chance of a watch: 20%

All 24 counties

Anson County, NC, Bladen County, NC, Brunswick County, NC, Columbus County, NC, Cumberland County, NC, Hoke County, NC, New Hanover County, NC, Pender County, NC, Richmond County, NC, Robeson County, NC, Scotland County, NC, Chesterfield County, SC, Clarendon County, SC, Darlington County, SC, Dillon County, SC, Florence County, SC, Georgetown County, SC, Horry County, SC, Kershaw County, SC, Lee County, SC, Marion County, SC, Marlboro County, SC, Sumter County, SC, Williamsburg County, SC

The radar

The Wilmington radar (KLTX), 97 km from the middle of the area, began a volume at 17:35 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 12:00Z, 5.5 hours before the alert went out and 161 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: 228 J/kg
Mixed-layer CIN: -41 J/kg
Mixed-layer LCL: 753 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 86 m²/s²
0-3 km storm-relative helicity: 126 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.9

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
Oct 11, 7:26 AM EDT	Mesoscale Discussion	SPC	Union	94 min
Oct 11, 4:42 PM EDT	Mesoscale Discussion	SPC	Bladen, Brunswick, Columbus, Cumberland, Duplin, Harnett and 9 more	2 hr

Nearby

Mesoscale Discussions in South Carolina, 2020 Mesoscale Discussions in North Carolina, 2020 Every mesoscale discussion in 2020

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.