Alert archive / Georgia / Mesoscale Discussions in 2011

Mesoscale Discussion 418

April 11, 20115 states

The Storm Prediction Center issued this mesoscale discussion at Apr 11, 2011, 6:42 PM CDT for 5 states. It was in force for 33 min.

The area

The outline as issued.

The facts

Issued
Apr 11, 2011, 6:42 PM CDT (23:42 UTC)
Expired
Apr 11, 2011, 7:15 PM CDT
In force
33 min
Issued by
the Storm Prediction Center
All 143 counties

Autauga County, AL, Bullock County, AL, Calhoun County, AL, Chambers County, AL, Cherokee County, AL, Chilton County, AL, Clay County, AL, Cleburne County, AL, Coosa County, AL, Elmore County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Montgomery County, AL, Randolph County, AL, Russell County, AL, Talladega County, AL, Tallapoosa County, AL, Baldwin County, GA, Banks County, GA, Barrow County, GA, Bartow County, GA, Bibb County, GA, Butts County, GA, Carroll County, GA, Catoosa County, GA, Chattahoochee County, GA, Chattooga County, GA, Cherokee County, GA, Clarke County, GA, Clayton County, GA, Cobb County, GA, Coweta County, GA, Crawford County, GA, Dawson County, GA, DeKalb County, GA, Douglas County, GA, Elbert County, GA, Fannin County, GA, Fayette County, GA, Floyd County, GA, Forsyth County, GA, Franklin County, GA, Fulton County, GA, Gilmer County, GA, Gordon County, GA, Greene County, GA, Gwinnett County, GA, Habersham County, GA, Hall County, GA, Hancock County, GA, Haralson County, GA, Harris County, GA, Hart County, GA, Heard County, GA, Henry County, GA, Jackson County, GA, Jasper County, GA, Jones County, GA, Lamar County, GA, Lincoln County, GA, Lumpkin County, GA, Madison County, GA, Marion County, GA, Meriwether County, GA, Monroe County, GA, Morgan County, GA, Murray County, GA, Muscogee County, GA, Newton County, GA, Oconee County, GA, Oglethorpe County, GA, Paulding County, GA, Pickens County, GA, Pike County, GA, Polk County, GA, Putnam County, GA, Rabun County, GA, Rockdale County, GA, Spalding County, GA, Stephens County, GA, Talbot County, GA, Taliaferro County, GA, Taylor County, GA, Towns County, GA, Troup County, GA, Union County, GA, Upson County, GA, Walton County, GA, White County, GA, Whitfield County, GA, Wilkes County, GA, Avery County, NC, Buncombe County, NC, Burke County, NC, Caldwell County, NC, Cherokee County, NC, Clay County, NC, Cleveland 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, Polk County, NC, Rutherford County, NC, Swain County, NC, Transylvania County, NC, Watauga County, NC, Yancey County, NC, Abbeville County, SC, Anderson County, SC, Cherokee County, SC, Greenville County, SC, Greenwood County, SC, Laurens County, SC, McCormick County, SC, Oconee County, SC, Pickens County, SC, Spartanburg County, SC, Blount County, TN, Bradley County, TN, Carter County, TN, Cocke County, TN, Grainger County, TN, Greene County, TN, Hamblen County, TN, Hawkins County, TN, Jefferson County, TN, Johnson County, TN, Knox County, TN, Loudon County, TN, McMinn County, TN, Monroe County, TN, Polk County, TN, Sevier County, TN, Sullivan County, TN, Unicoi County, TN, Union County, TN, Washington County, TN

The radar

The Atlanta radar (KFFC), 141 km from the middle of the area, began a volume at 23:40 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

Birmingham, AL (KBMX), launched 12:00Z, 11.7 hours before the alert went out and 306 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, Birmingham, AL at 12:00Z on 2011-04-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 9 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, Birmingham, AL at 12:00Z on 2011-04-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 109 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
9 J/kg
Mixed-layer CIN
-684 J/kg
Mixed-layer LCL
606 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
109 m²/s²
0-3 km storm-relative helicity
179 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
Apr 11, 8:58 AM CDTMesoscale DiscussionSPCColbert, Cullman, Fayette, Franklin, Lamar, Lauderdale and 7 more62 min
Apr 11, 10:41 AM CDTMesoscale DiscussionSPCColbert, Cullman, Fayette, Franklin, Jackson, Lamar and 9 more64 min
Apr 11, 3:56 PM CDTMesoscale DiscussionSPCAutauga, Bibb, Blount, Calhoun, Chilton, Choctaw and 32 more34 min
Apr 11, 4:05 PM CDTTornado WatchSPCBibb, Blount, Chilton, Choctaw, Clarke, Dallas and 16 more6 hr
Apr 11, 5:11 PM CDTTornado WatchSPCColbert, Cullman, DeKalb, Franklin, Jackson, Lauderdale and 5 more7 hr
Apr 11, 5:53 PM CDTMesoscale DiscussionSPCBibb, Greene, Jefferson, Shelby, Tuscaloosa97 min
Apr 11, 10:31 AM CDTTornado WatchSPCBenton, Carroll, Cheatham, Chester, Clay, Davidson and 30 more6 hr
Apr 11, 12:37 PM CDTMesoscale DiscussionSPCBenton, Carroll, Cheatham, Chester, Clay, Crockett and 35 more53 min

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.