Alert archive / Georgia / Mesoscale Discussions in 2011

Mesoscale Discussion 637

April 27, 20114 states

The Storm Prediction Center issued this mesoscale discussion at Apr 27, 2011, 5:41 PM CDT for 4 states. It was in force for 34 min.

The area

The outline as issued.

The facts

Issued
Apr 27, 2011, 5:41 PM CDT (22:41 UTC)
Expired
Apr 27, 2011, 6:15 PM CDT
In force
34 min
Issued by
the Storm Prediction Center
All 137 counties

Barbour County, AL, Bullock County, AL, Chambers County, AL, Crenshaw County, AL, Elmore County, AL, Lee County, AL, Macon County, AL, Montgomery County, AL, Pike County, AL, Randolph County, AL, Russell County, AL, Tallapoosa County, AL, Baldwin County, GA, Banks County, GA, Barrow County, GA, Bartow County, GA, Bibb County, GA, Bleckley County, GA, Butts County, GA, Carroll County, GA, Chattahoochee County, GA, Cherokee County, GA, Clarke County, GA, Clay County, GA, Clayton County, GA, Cobb County, GA, Coweta County, GA, Crawford County, GA, Crisp County, GA, Dawson County, GA, DeKalb County, GA, Dodge County, GA, Dooly County, GA, Douglas County, GA, Elbert County, GA, Fannin County, GA, Fayette County, GA, Forsyth County, GA, Franklin County, GA, Fulton County, GA, Gilmer County, GA, Glascock 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, Houston County, GA, Jackson County, GA, Jasper County, GA, Jones County, GA, Lamar County, GA, Lee County, GA, Lincoln County, GA, Lumpkin County, GA, Macon County, GA, Madison County, GA, Marion County, GA, McDuffie County, GA, Meriwether County, GA, Monroe County, GA, Morgan County, GA, Muscogee County, GA, Newton County, GA, Oconee County, GA, Oglethorpe County, GA, Paulding County, GA, Peach County, GA, Pickens County, GA, Pike County, GA, Polk County, GA, Pulaski County, GA, Putnam County, GA, Quitman County, GA, Rabun County, GA, Randolph County, GA, Rockdale County, GA, Schley County, GA, Spalding County, GA, Stephens County, GA, Stewart County, GA, Sumter County, GA, Talbot County, GA, Taliaferro County, GA, Taylor County, GA, Terrell County, GA, Towns County, GA, Troup County, GA, Twiggs County, GA, Union County, GA, Upson County, GA, Walton County, GA, Warren County, GA, Washington County, GA, Webster County, GA, White County, GA, Wilcox County, GA, Wilkes County, GA, Wilkinson County, GA, Alexander County, NC, Avery County, NC, Buncombe County, NC, Burke County, NC, Caldwell County, NC, Catawba County, NC, Cherokee County, NC, Clay County, NC, Cleveland County, NC, Gaston County, NC, Haywood County, NC, Henderson County, NC, Iredell County, NC, Jackson County, NC, Lincoln County, NC, Macon County, NC, McDowell County, NC, Mitchell County, NC, Polk County, NC, Rutherford County, NC, Transylvania 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, Union County, SC

The radar

The Atlanta radar (KFFC), 59 km from the middle of the area, began a volume at 22:41 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, 10.7 hours before the alert went out and 53 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 2011-04-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 748 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 2011-04-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 345 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
748 J/kg
Mixed-layer CIN
-41 J/kg
Mixed-layer LCL
501 m above ground
0-6 km bulk shear
51 kt
0-1 km storm-relative helicity
345 m²/s²
0-3 km storm-relative helicity
460 m²/s²
Significant tornado parameter
1.5
Supercell composite
5.4

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 26, 7:59 PM CDTMesoscale DiscussionSPCColbert, Franklin, Lamar, Lauderdale, Lawrence, Limestone and 1 more2 hr
Apr 26, 9:33 PM CDTTornado Watch PDSSPCColbert, Franklin, Lauderdale7 hr
Apr 26, 11:33 PM CDTMesoscale DiscussionSPCColbert, Franklin, Lamar, Lauderdale, Marion117 min
Apr 27, 1:56 AM CDTMesoscale DiscussionSPCBibb, Blount, Cullman, Fayette, Greene, Hale and 12 more64 min
Apr 27, 2:26 AM CDTTornado WatchSPCBibb, Blount, Calhoun, Cherokee, Chilton, Clay and 29 more6 hr
Apr 27, 8:08 AM CDTTornado WatchSPCColbert, Cullman, DeKalb, Fayette, Franklin, Jackson and 10 more6 hr
Apr 27, 10:45 AM CDTMesoscale DiscussionSPCGreene, Lamar, Marion, Pickens, Sumter90 min
Apr 27, 11:39 AM CDTMesoscale DiscussionSPCCullman, DeKalb, Jackson, Madison, Marshall, Morgan66 min
Apr 27, 1:05 PM CDTMesoscale DiscussionSPCBibb, Blount, Calhoun, Cherokee, Chilton, Choctaw and 27 more85 min
Apr 27, 1:42 PM CDTTornado Watch PDSSPCAutauga, Bibb, Blount, Butler, Calhoun, Cherokee and 41 more8 hr
Apr 27, 2:56 PM CDTMesoscale DiscussionSPCBibb, Blount, Calhoun, Cherokee, Chilton, Choctaw and 33 more2 hr
Apr 27, 5:01 PM CDTMesoscale DiscussionSPCAutauga, Bibb, Blount, Butler, Calhoun, Cherokee and 38 more89 min
Apr 27, 5:52 PM CDTTornado Watch PDSSPCBarbour, Bullock, Chambers, Elmore, Lee, Macon and 5 more9 hr
Apr 27, 6:39 PM CDTMesoscale DiscussionSPCAutauga, Bibb, Blount, Calhoun, Cherokee, Chilton and 26 more66 min
Apr 27, 6:19 AM CDTMesoscale DiscussionSPCBartow, Carroll, Chattooga, Cherokee, Clayton, Cobb and 22 more56 min
Apr 27, 6:48 AM CDTTornado WatchSPCBartow, Butts, Carroll, Catoosa, Chattooga, Cherokee and 36 more2 hr
Apr 27, 7:34 AM CDTTornado WatchSPCCherokee, Clay4 hr
Apr 27, 10:27 AM CDTTornado WatchSPCCherokee, Clay6 hr
Apr 27, 11:51 AM CDTMesoscale DiscussionSPCAlamance, Anson, Bertie, Bladen, Cabarrus, Caswell and 47 more84 min
Apr 27, 12:23 PM CDTTornado WatchSPCAlamance, Anson, Caswell, Chatham, Cumberland, Davidson and 28 more5 hr
Apr 27, 1:03 PM CDTMesoscale DiscussionSPCCherokee, Clay, Graham57 min
Apr 27, 2:22 PM CDTMesoscale DiscussionSPCAlleghany, Ashe, Avery, Buncombe, Caldwell, Haywood and 6 more83 min
Apr 27, 3:36 PM CDTTornado Watch PDSSPCCherokee, Clay8 hr
Apr 27, 5:00 PM CDTMesoscale DiscussionSPCAlamance, Caswell, Durham, Franklin, Granville, Guilford and 5 more60 min
Apr 27, 5:15 PM CDTTornado WatchSPCAlamance, Alleghany, Ashe, Caswell, Davidson, Durham and 15 more6 hr
Apr 27, 6:55 PM CDTMesoscale DiscussionSPCAlamance, Caswell, Granville, Orange, Person, Rockingham65 min

Nearby

Mesoscale Discussions in Georgia, 2011Mesoscale Discussions in North Carolina, 2011Mesoscale Discussions in Alabama, 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.