Alert archive / Alabama / Mesoscale Discussions in 2013

Mesoscale Discussion 445

April 11, 201318 counties in Alabama; Lincoln County, Tennessee

The Storm Prediction Center issued this mesoscale discussion at Apr 11, 2013, 2:21 PM CDT for 18 counties in Alabama; Lincoln County, Tennessee. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued
Apr 11, 2013, 2:21 PM CDT (19:21 UTC)
Expired
Apr 11, 2013, 3:45 PM CDT
In force
84 min
Issued by
the Storm Prediction Center

Counties Autauga County, AL, Bibb County, AL, Blount County, AL, Chilton County, AL, Coosa County, AL, Cullman County, AL, Dallas County, AL, Elmore County, AL, Hale County, AL, Jefferson County, AL, Madison County, AL, Marengo County, AL, Marshall County, AL, Morgan County, AL, Perry County, AL, Shelby County, AL, St. Clair County, AL, Talladega County, AL, Lincoln County, TN

The radar

The Birmingham radar (KBMX), 43 km from the middle of the area, began a volume at 19:22 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, 7.4 hours before the alert went out and 42 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 2013-04-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 35 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 2013-04-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 143 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
35 J/kg
Mixed-layer CIN
-291 J/kg
Mixed-layer LCL
635 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
143 m²/s²
0-3 km storm-relative helicity
169 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, 10:41 AM CDTMesoscale DiscussionSPCColbert, Cullman, Fayette, Franklin, Greene, Hale and 12 more2 hr
Apr 11, 11:56 AM CDTTornado WatchSPCAutauga, Bibb, Blount, Chilton, Colbert, Coosa and 31 more7 hr
Apr 11, 12:59 PM CDTMesoscale DiscussionSPCBaldwin, Butler, Choctaw, Clarke, Conecuh, Covington and 5 more91 min
Apr 11, 1:30 PM CDTTornado WatchSPCBaldwin, Butler, Choctaw, Clarke, Conecuh, Covington and 6 more8 hr
Apr 11, 3:26 PM CDTMesoscale DiscussionSPCChambers, Cleburne, Lee, Randolph, Russell94 min
Apr 11, 3:45 PM CDTTornado WatchSPCBarbour, Bullock, Calhoun, Chambers, Cherokee, Clay and 9 more6 hr
Apr 11, 5:03 PM CDTMesoscale DiscussionSPCCoffee, Dale, Geneva, Henry, Houston2 hr
Apr 11, 5:35 PM CDTMesoscale DiscussionSPCBaldwin, Butler, Conecuh, Covington, Crenshaw, Escambia and 2 more115 min
Apr 11, 5:54 PM CDTMesoscale DiscussionSPCAutauga, Bullock, Calhoun, Chambers, Cherokee, Clay and 11 more96 min
Apr 10, 7:55 PM CDTMesoscale DiscussionSPCDyer, Lake, Lauderdale, Obion, Weakley95 min
Apr 10, 8:28 PM CDTTornado WatchSPCCarroll, Chester, Crockett, Dyer, Fayette, Gibson and 11 more7 hr
Apr 10, 11:08 PM CDTMesoscale DiscussionSPCCrockett, Dyer, Fayette, Gibson, Hardeman, Haywood and 7 more97 min
Apr 11, 12:34 PM CDTSevere Thunderstorm WatchSPCBedford, Cannon, Clay, Coffee, Cumberland, DeKalb and 17 more6 hr
Apr 11, 2:59 PM CDTMesoscale DiscussionSPCBedford, Bledsoe, Cannon, Clay, Coffee, Cumberland and 26 more91 min
Apr 11, 5:06 PM CDTMesoscale DiscussionSPCAnderson, Bledsoe, Blount, Bradley, Campbell, Claiborne and 25 more84 min
Apr 11, 5:36 PM CDTTornado WatchSPCAnderson, Bledsoe, Blount, Bradley, Campbell, Carter and 30 more7 hr

Nearby

Mesoscale Discussions in Alabama, 2013Mesoscale Discussions in Tennessee, 2013Every mesoscale discussion in 2013

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.