Alert archive / Georgia / Mesoscale Discussions in 2011

Mesoscale Discussion 776

May 13, 20116 states

The Storm Prediction Center issued this mesoscale discussion at May 13, 2011, 3:47 PM EDT for 6 states. It was in force for 58 min.

The area

The outline as issued.

The facts

Issued
May 13, 2011, 3:47 PM EDT (19:47 UTC)
Expired
May 13, 2011, 4:45 PM EDT
In force
58 min
Issued by
the Storm Prediction Center
All 79 counties

Banks County, GA, Barrow County, GA, Bartow County, GA, Cherokee County, GA, Cobb County, GA, Dawson County, GA, DeKalb County, GA, Fannin County, GA, Forsyth County, GA, Franklin County, GA, Fulton County, GA, Gilmer County, GA, Gordon County, GA, Gwinnett County, GA, Habersham County, GA, Hall County, GA, Haralson County, GA, Jackson County, GA, Lumpkin County, GA, Paulding County, GA, Pickens County, GA, Polk County, GA, Rabun County, GA, Stephens County, GA, Towns County, GA, Union County, GA, Walton County, GA, White County, GA, Harlan County, KY, Letcher County, KY, Ashe County, NC, Avery County, NC, Buncombe County, NC, Cherokee County, NC, Clay County, NC, Graham County, NC, Haywood County, NC, Henderson County, NC, Jackson County, NC, Macon County, NC, Madison County, NC, McDowell County, NC, Mitchell County, NC, Swain County, NC, Transylvania County, NC, Watauga County, NC, Yancey County, NC, Oconee County, SC, Pickens County, SC, Blount County, TN, Carter County, TN, Cocke County, TN, Grainger County, TN, Greene County, TN, Hamblen County, TN, Hancock County, TN, Hawkins County, TN, Jefferson County, TN, Johnson County, TN, Monroe County, TN, Sevier County, TN, Sullivan County, TN, Unicoi County, TN, Washington County, TN, Bland County, VA, Buchanan County, VA, City of Bristol, VA, City of Norton, VA, Dickenson County, VA, Grayson County, VA, Lee County, VA, Pulaski County, VA, Russell County, VA, Scott County, VA, Smyth County, VA, Tazewell County, VA, Washington County, VA, Wise County, VA, Wythe County, VA

The radar

The Greer radar (KGSP), 101 km from the middle of the area, began a volume at 19:49 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Peachtre/Fal Fld, GA (KFFC), launched 12:00Z, 7.8 hours before the alert went out and 227 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, Peachtre/Fal Fld, GA at 12:00Z on 2011-05-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 696 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, Peachtre/Fal Fld, GA at 12:00Z on 2011-05-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -33 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
696 J/kg
Mixed-layer CIN
-88 J/kg
Mixed-layer LCL
1122 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
-33 m²/s²
0-3 km storm-relative helicity
32 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.

IssuedProductOfficeCountiesLasted
May 13, 12:22 PM EDTMesoscale DiscussionSPCCatoosa, Chattooga, Fannin, Floyd, Gilmer, Gordon and 4 more113 min
May 13, 1:10 PM EDTSevere Thunderstorm WatchSPCBartow, Catoosa, Chattooga, Cherokee, Dade, Dawson and 18 more6 hr
May 13, 4:44 PM EDTSevere Thunderstorm WatchSPCElbert, Franklin, Hart, Stephens8 hr
May 13, 1:01 PM EDTMesoscale DiscussionSPCCarlisle, Fulton, Graves, Hickman89 min
May 13, 1:31 PM EDTSevere Thunderstorm WatchSPCBallard, Calloway, Carlisle, Fulton, Graves, Hickman and 3 more6 hr
May 13, 3:44 PM EDTMesoscale DiscussionSPCBallard, Carlisle, Fulton, Graves, Hickman2 hr
May 13, 6:03 PM EDTMesoscale DiscussionSPCChristian, Hopkins, Logan, Muhlenberg, Todd, Trigg57 min
May 13, 6:54 PM EDTSevere Thunderstorm WatchSPCAllen, Butler, Caldwell, Calloway, Christian, Crittenden and 17 more6 hr
May 13, 4:36 PM EDTMesoscale DiscussionSPCAlamance, Alexander, Alleghany, Anson, Ashe, Avery and 28 more24 min
May 13, 7:21 PM EDTSevere Thunderstorm WatchSPCBladen, Cumberland, Duplin, Edgecombe, Franklin, Greene and 11 more6 hr

Nearby

Mesoscale Discussions in Georgia, 2011Mesoscale Discussions in North Carolina, 2011Mesoscale Discussions in Tennessee, 2011Every 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.