Alert archive / Georgia / Mesoscale Discussions in 2011

Mesoscale Discussion 501

April 21, 201111 counties in Georgia; 5 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at Apr 21, 2011, 4:09 AM EDT for 11 counties in Georgia; 5 counties in South Carolina. It was in force for 96 min.

The area

The outline as issued.

The facts

Issued: Apr 21, 2011, 4:09 AM EDT (08:09 UTC)
Expired: Apr 21, 2011, 5:45 AM EDT
In force: 96 min
Issued by: the Storm Prediction Center

Counties Clarke County, GA, Elbert County, GA, Franklin County, GA, Greene County, GA, Hart County, GA, Lincoln County, GA, Madison County, GA, Oglethorpe County, GA, Stephens County, GA, Taliaferro County, GA, Wilkes County, GA, Abbeville County, SC, Anderson County, SC, Greenwood County, SC, Laurens County, SC, McCormick County, SC

The radar

The Greer radar (KGSP), 103 km from the middle of the area, began a volume at 08:09 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

Peachtre/Fal Fld, GA (KFFC), launched 00:00Z, 8.2 hours before the alert went out and 173 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: 316 J/kg
Mixed-layer CIN: -171 J/kg
Mixed-layer LCL: 1406 m above ground
0-6 km bulk shear: 17 kt
0-1 km storm-relative helicity: 76 m²/s²
0-3 km storm-relative helicity: 108 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 21, 2:05 AM EDT	Mesoscale Discussion	SPC	Baldwin, Barrow, Bartow, Bibb, Butts, Carroll and 39 more	85 min
Apr 21, 2:32 AM EDT	Severe Thunderstorm Watch	SPC	Baldwin, Banks, Barrow, Bartow, Butts, Carroll and 51 more	2 hr
Apr 21, 5:40 PM EDT	Mesoscale Discussion	SPC	Appling, Bacon, Brantley, Bryan, Bulloch, Burke and 22 more	3 hr

Nearby

Mesoscale Discussions in Georgia, 2011 Mesoscale Discussions in South Carolina, 2011 Every mesoscale discussion in 2011

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.