Alert archive / Georgia / Mesoscale Discussions in 2011

Mesoscale Discussion 354

April 4, 201112 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Apr 4, 2011, 9:18 PM EDT for 12 counties in Georgia. It was in force for 87 min.

The area

The outline as issued.

The facts

Issued: Apr 4, 2011, 9:18 PM EDT (01:18 UTC)
Expired: Apr 4, 2011, 10:45 PM EDT
In force: 87 min
Issued by: the Storm Prediction Center

Counties Bartow County, GA, Carroll County, GA, Cherokee County, GA, Cobb County, GA, DeKalb County, GA, Douglas County, GA, Floyd County, GA, Forsyth County, GA, Fulton County, GA, Gwinnett County, GA, Paulding County, GA, Polk County, GA

The radar

The Atlanta radar (KFFC), 66 km from the middle of the area, began a volume at 01:20 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.

Severe Thunderstorm Watch 97Apr 4, 9:45 PM EDT

The nearest sounding before it

Peachtre/Fal Fld, GA (KFFC), launched 00:00Z, 1.3 hours before the alert went out and 66 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: 176 J/kg
Mixed-layer CIN: -41 J/kg
Mixed-layer LCL: 1790 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 158 m²/s²
0-3 km storm-relative helicity: 251 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.0

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 4, 9:45 PM EDT	Severe Thunderstorm Watch	SPC	Elbert, Franklin, Habersham, Hart, Rabun, Stephens	5 hr
Apr 4, 10:05 PM EDT	Mesoscale Discussion	SPC	Baker, Baldwin, Ben Hill, Bibb, Bleckley, Butts and 61 more	55 min
Apr 4, 10:28 PM EDT	Tornado Watch	SPC	Baker, Baldwin, Ben Hill, Bibb, Bleckley, Butts and 73 more	6 hr
Apr 5, 12:21 AM EDT	Mesoscale Discussion	SPC	Baker, Baldwin, Bibb, Bleckley, Butts, Calhoun and 62 more	84 min
Apr 5, 12:48 AM EDT	Tornado Watch	SPC	Burke, Columbia, Lincoln, McDuffie, Richmond	5 hr
Apr 5, 2:41 AM EDT	Tornado Watch	SPC	Appling, Atkinson, Bacon, Berrien, Brantley, Brooks and 25 more	6 hr
Apr 5, 2:55 AM EDT	Mesoscale Discussion	SPC	Appling, Atkinson, Bacon, Ben Hill, Berrien, Bleckley and 55 more	2 hr
Apr 5, 3:34 AM EDT	Mesoscale Discussion	SPC	Burke	116 min
Apr 5, 5:39 AM EDT	Mesoscale Discussion	SPC	Brantley, Camden, Charlton, Chatham, Glynn, Liberty and 1 more	2 hr

Nearby

Mesoscale Discussions in Georgia, 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.