Alert archive / South Carolina / Mesoscale Discussions in 2017

Mesoscale Discussion 1643

September 11, 201714 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at Sep 11, 2017, 9:11 PM EDT for 14 counties in South Carolina. It was in force for 64 min.

The area

The outline as issued.

The facts

Issued
Sep 11, 2017, 9:11 PM EDT (01:11 UTC)
Expired
Sep 11, 2017, 10:15 PM EDT
In force
64 min
Issued by
the Storm Prediction Center

Counties Allendale County, SC, Bamberg County, SC, Barnwell County, SC, Beaufort County, SC, Berkeley County, SC, Charleston County, SC, Clarendon County, SC, Colleton County, SC, Dorchester County, SC, Georgetown County, SC, Hampton County, SC, Jasper County, SC, Orangeburg County, SC, Williamsburg County, SC

The radar

The Charleston,SC radar (KCLX), 112 km from the middle of the area, began a volume at 01:12 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, 1.2 hours before the alert went out and 27 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 2017-09-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 458 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 2017-09-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 334 square meters per square second.19395878Sfc1 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
458 J/kg
Mixed-layer CIN
-17 J/kg
Mixed-layer LCL
652 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
334 m²/s²
0-3 km storm-relative helicity
383 m²/s²
Significant tornado parameter
0.8
Supercell composite
6.7

Open this sounding in Storm Lab

The text

As transmitted.

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Nearby

Mesoscale Discussions in South Carolina, 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.