Alert archive / South Carolina / Mesoscale Discussions in 2017

Mesoscale Discussion 307

March 21, 20174 counties in Georgia; 17 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at Mar 21, 2017, 11:18 PM EDT for 4 counties in Georgia; 17 counties in South Carolina. It was in force for 57 min.

The area

The outline as issued.

The facts

Issued
Mar 21, 2017, 11:18 PM EDT (03:18 UTC)
Expired
Mar 22, 2017, 12:15 AM EDT
In force
57 min
Issued by
the Storm Prediction Center
All 21 counties

Burke County, GA, Jenkins County, GA, Richmond County, GA, Screven County, GA, Aiken County, SC, Allendale County, SC, Bamberg County, SC, Barnwell County, SC, Berkeley County, SC, Calhoun County, SC, Charleston County, SC, Clarendon County, SC, Colleton County, SC, Dorchester County, SC, Florence County, SC, Georgetown County, SC, Hampton County, SC, Lee County, SC, Orangeburg County, SC, Sumter County, SC, Williamsburg County, SC

The radar

The Columbia radar (KCAE), 79 km from the middle of the area, began a volume at 03:19 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, 3.3 hours before the alert went out and 79 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-pSkew-T log-p diagram, Charleston AFB, SC at 00:00Z on 2017-03-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 130 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Charleston AFB, SC at 00:00Z on 2017-03-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 139 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
130 J/kg
Mixed-layer CIN
-258 J/kg
Mixed-layer LCL
2122 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
139 m²/s²
0-3 km storm-relative helicity
162 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

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.

IssuedProductOfficeCountiesLasted
Mar 21, 8:35 PM EDTSevere Thunderstorm WatchSPCBurke, Butts, Columbia, Glascock, Hancock, Jasper and 9 more5 hr

Nearby

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