Alert archive / South Carolina / Mesoscale Discussions in 2018

Mesoscale Discussion 285

April 23, 2018Chatham County, Georgia; Beaufort County, Charleston County, South Carolina

The Storm Prediction Center issued this mesoscale discussion at Apr 23, 2018, 11:09 AM EDT for Chatham County, Georgia; Beaufort County, Charleston County, South Carolina. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Apr 23, 2018, 11:09 AM EDT (15:09 UTC)
Expired
Apr 23, 2018, 1:15 PM EDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
5%

Counties Chatham County, GA, Beaufort County, SC, Charleston County, SC

The radar

The Charleston,SC radar (KCLX), 56 km from the middle of the area, began a volume at 15:10 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, 3.2 hours before the alert went out and 68 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 12:00Z on 2018-04-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 6 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 12:00Z on 2018-04-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 121 square meters per square second.193958Sfc1 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
6 J/kg
Mixed-layer CIN
-6 J/kg
Mixed-layer LCL
558 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
121 m²/s²
0-3 km storm-relative helicity
277 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
Apr 22, 8:11 PM EDTMesoscale DiscussionSPCDecatur, Early, Miller, Seminole64 min
Apr 23, 3:59 PM EDTMesoscale DiscussionSPCAppling, Bacon, Baldwin, Ben Hill, Bibb, Bleckley and 61 more61 min

Nearby

Mesoscale Discussions in South Carolina, 2018Mesoscale Discussions in Georgia, 2018Every 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.