Alert archive / South Carolina / Mesoscale Discussions in 2017

Mesoscale Discussion 551

April 23, 20178 counties in Georgia; 18 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at Apr 23, 2017, 2:24 PM EDT for 8 counties in Georgia; 18 counties in South Carolina. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: Apr 23, 2017, 2:24 PM EDT (18:24 UTC)
Expired: Apr 23, 2017, 5:00 PM EDT
In force: 3 hr
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 26 counties

Columbia County, GA, Elbert County, GA, Lincoln County, GA, McDuffie County, GA, Richmond County, GA, Taliaferro County, GA, Warren County, GA, Wilkes County, GA, Abbeville County, SC, Aiken County, SC, Bamberg County, SC, Barnwell County, SC, Berkeley County, SC, Calhoun County, SC, Clarendon County, SC, Dorchester County, SC, Edgefield County, SC, Georgetown County, SC, Greenwood County, SC, Lexington County, SC, McCormick County, SC, Orangeburg County, SC, Richland County, SC, Saluda County, SC, Sumter County, SC, Williamsburg County, SC

The radar

The Columbia radar (KCAE), 43 km from the middle of the area, began a volume at 18:28 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, 6.4 hours before the alert went out and 119 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: 373 J/kg
Mixed-layer CIN: -44 J/kg
Mixed-layer LCL: 922 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 94 m²/s²
0-3 km storm-relative helicity: 99 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.8

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
Apr 23, 12:02 PM EDT	Mesoscale Discussion	SPC	Baker, Bibb, Bleckley, Butts, Calhoun, Chattahoochee and 38 more	118 min

Nearby

Mesoscale Discussions in South Carolina, 2017 Mesoscale Discussions in Georgia, 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.