Alert archive / Alabama / Mesoscale Discussions in 2011

Mesoscale Discussion 626

April 27, 201133 counties in Alabama; Chattooga County, Dade County, Walker County, Georgia; 7 counties in Tennessee

The Storm Prediction Center issued this mesoscale discussion at Apr 27, 2011, 1:05 PM CDT for 33 counties in Alabama; Chattooga County, Dade County, Walker County, Georgia; 7 counties in Tennessee. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued
Apr 27, 2011, 1:05 PM CDT (18:05 UTC)
Expired
Apr 27, 2011, 2:30 PM CDT
In force
85 min
Issued by
the Storm Prediction Center
All 43 counties

Bibb County, AL, Blount County, AL, Calhoun County, AL, Cherokee County, AL, Chilton County, AL, Choctaw County, AL, Clarke County, AL, Cullman County, AL, Dallas County, AL, DeKalb County, AL, Etowah County, AL, Fayette County, AL, Greene County, AL, Hale County, AL, Jackson County, AL, Jefferson County, AL, Lawrence County, AL, Limestone County, AL, Madison County, AL, Marengo County, AL, Marion County, AL, Marshall County, AL, Morgan County, AL, Perry County, AL, Pickens County, AL, Shelby County, AL, St. Clair County, AL, Sumter County, AL, Talladega County, AL, Tuscaloosa County, AL, Walker County, AL, Wilcox County, AL, Winston County, AL, Chattooga County, GA, Dade County, GA, Walker County, GA, Franklin County, TN, Giles County, TN, Lawrence County, TN, Lincoln County, TN, Marshall County, TN, Maury County, TN, Moore County, TN

The radar

The Birmingham radar (KBMX), 42 km from the middle of the area, began a volume at 18:06 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, 6.1 hours before the alert went out and 41 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 2011-04-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 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 2011-04-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -359 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
587 m above ground
0-6 km bulk shear
60 kt
0-1 km storm-relative helicity
-359 m²/s²
0-3 km storm-relative helicity
-197 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

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, 1:42 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, 5:41 PM CDTMesoscale DiscussionSPCBarbour, Bullock, Chambers, Crenshaw, Elmore, Lee and 6 more34 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 26, 9:13 PM CDTMesoscale DiscussionSPCBenton, Carroll, Chester, Crockett, Dyer, Fayette and 16 more62 min
Apr 26, 9:58 PM CDTTornado WatchSPCBedford, Benton, Cannon, Carroll, Cheatham, Chester and 40 more7 hr
Apr 27, 4:33 AM CDTMesoscale DiscussionSPCBedford, Cannon, Clay, Coffee, Cumberland, DeKalb and 15 more57 min
Apr 27, 5:07 AM CDTTornado WatchSPCBedford, Bledsoe, Cannon, Clay, Coffee, Cumberland and 27 more5 hr
Apr 27, 6:25 AM CDTMesoscale DiscussionSPCFayette, Hardeman, Shelby, Tipton65 min
Apr 27, 7:34 AM CDTTornado WatchSPCAnderson, Blount, Bradley, Campbell, Claiborne, Grainger and 13 more4 hr
Apr 27, 10:27 AM CDTTornado WatchSPCAnderson, Bedford, Bledsoe, Blount, Bradley, Cannon and 29 more6 hr
Apr 27, 11:02 AM CDTTornado Watch PDSSPCHardin, McNairy8 hr
Apr 27, 12:08 PM CDTMesoscale DiscussionSPCBenton, Carroll, Cheatham, Chester, Crockett, Decatur and 21 more67 min
Apr 27, 12:42 PM CDTSevere Thunderstorm WatchSPCBenton, Carroll, Cheatham, Chester, Crockett, Davidson and 27 more5 hr
Apr 27, 1:03 PM CDTMesoscale DiscussionSPCBledsoe, Blount, Bradley, Grundy, Hamilton, Loudon and 10 more57 min
Apr 27, 2:22 PM CDTMesoscale DiscussionSPCAnderson, Blount, Campbell, Carter, Claiborne, Cocke and 17 more83 min
Apr 27, 3:06 PM CDTMesoscale DiscussionSPCBenton, Carroll, Cheatham, Chester, Crockett, Davidson and 22 more54 min
Apr 27, 3:29 PM CDTTornado WatchSPCCarroll, Chester, Crockett, Decatur, Dyer, Fayette and 13 more5 hr
Apr 27, 3:36 PM CDTTornado Watch PDSSPCAnderson, Bedford, Benton, Bledsoe, Blount, Bradley and 66 more8 hr
Apr 27, 5:38 PM CDTMesoscale DiscussionSPCAnderson, Bedford, Bledsoe, Blount, Bradley, Cannon and 36 more97 min

Nearby

Mesoscale Discussions in Alabama, 2011Mesoscale Discussions in Tennessee, 2011Mesoscale Discussions in Georgia, 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.