Alert archive / Alabama / Mesoscale Discussions in 2012

Mesoscale Discussion 466

April 5, 201229 counties in Alabama; Heard County, Georgia

The Storm Prediction Center issued this mesoscale discussion at Apr 5, 2012, 6:15 PM CDT for 29 counties in Alabama; Heard County, Georgia. It was in force for 45 min.

The area

The outline as issued.

The facts

Issued
Apr 5, 2012, 6:15 PM CDT (23:15 UTC)
Expired
Apr 5, 2012, 7:00 PM CDT
In force
45 min
Issued by
the Storm Prediction Center
Concerning
Severe potential...watch likely
All 30 counties

Autauga County, AL, Bibb County, AL, Blount 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, Cullman County, AL, Dallas County, AL, DeKalb County, AL, Elmore County, AL, Etowah County, AL, Jefferson County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Marshall County, AL, Montgomery County, AL, Morgan County, AL, Randolph County, AL, Russell County, AL, Shelby County, AL, St. Clair County, AL, Talladega County, AL, Tallapoosa County, AL, Heard County, GA

The radar

The Birmingham radar (KBMX), 71 km from the middle of the area, began a volume at 23:14 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, 11.3 hours before the alert went out and 72 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 2012-04-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 315 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 2012-04-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -91 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
315 J/kg
Mixed-layer CIN
-31 J/kg
Mixed-layer LCL
754 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
-91 m²/s²
0-3 km storm-relative helicity
-43 m²/s²
Significant tornado parameter
0.0
Supercell composite
-1.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

713 
ACUS11 KWNS 052315
SWOMCD
SPC MCD 052315 COR
GAZ000-ALZ000-060000-

MESOSCALE DISCUSSION 0466
NWS STORM PREDICTION CENTER NORMAN OK
0615 PM CDT THU APR 05 2012

AREAS AFFECTED...CNTRL AND ERN AL...FAR WRN GA

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 

VALID 052315Z - 060000Z

CORRECTED TO UPDATE GRAPHIC

AN ISOLATED WIND DAMAGE AND LARGE HAIL THREAT SHOULD EXIST AS STORMS
MOVE EWD ACROSS ECNTRL AL OVER THE NEXT COUPLE HOURS. WW ISSUANCE IS
BEING CONSIDERED ACROSS THE REGION.

THUNDERSTORMS ARE INCREASING IN COVERAGE ACROSS WCNTRL AL ALONG A
NARROW AXIS OF MODERATE INSTABILITY WHERE SBCAPE IS ESTIMATED TO BE
AROUND 1000 J/KG. THIS COMBINED WITH 50 KT OF DEEP LAYER SHEAR
EVIDENT ON THE BIRMINGHAM AL WSR-88D VWP SHOULD SUPPORT A SUPERCELL
THREAT EARLY THIS EVENING. ISOLATED LARGE HAIL WILL BE POSSIBLE. IF
THE STORMS CAN DEVELOP INTO A LINE...THEN A WIND DAMAGE THREAT MAY
ALSO DEVELOP ACROSS THE REGION.

..BROYLES.. 04/05/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...FFC...BMX...HUN...MOB...

LAT...LON   34318533 34738583 34598692 33788725 32208719 31818636
            32058521 32578496 34318533

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 5, 7:36 AM CDTMesoscale DiscussionSPCChoctaw, Greene, Hale, Marengo, Perry, Pickens and 2 more54 min
Apr 5, 9:14 AM CDTSevere Thunderstorm WatchSPCAutauga, Barbour, Bibb, Bullock, Butler, Chambers and 34 more8 hr
Apr 5, 10:41 AM CDTMesoscale DiscussionSPCAutauga, Bibb, Butler, Chilton, Choctaw, Clarke and 15 more94 min
Apr 5, 12:09 PM CDTMesoscale DiscussionSPCColbert, Cullman, Franklin, Lauderdale, Lawrence, Limestone and 4 more96 min
Apr 5, 1:12 PM CDTMesoscale DiscussionSPCBarbour, Bullock, Chambers, Clay, Coffee, Covington and 11 more93 min
Apr 5, 1:21 PM CDTSevere Thunderstorm WatchSPCColbert, DeKalb, Franklin, Jackson, Lauderdale, Lawrence and 4 more8 hr
Apr 5, 1:58 PM CDTSevere Thunderstorm WatchSPCCoffee, Dale, Geneva, Henry, Houston6 hr
Apr 5, 3:06 PM CDTMesoscale DiscussionSPCColbert, DeKalb, Franklin, Jackson, Lauderdale, Lawrence and 4 more54 min
Apr 5, 3:46 PM CDTMesoscale DiscussionSPCBlount, Calhoun, Cullman, Etowah, Fayette, Jefferson and 7 more59 min
Apr 5, 3:49 PM CDTMesoscale DiscussionSPCGeneva, Henry, Houston86 min
Apr 5, 6:14 PM CDTSevere Thunderstorm WatchSPCAutauga, Bibb, Blount, Bullock, Calhoun, Chambers and 21 more3 hr
Apr 5, 12:03 PM CDTMesoscale DiscussionSPCBanks, Burke, Clarke, Columbia, Effingham, Elbert and 24 more87 min
Apr 5, 12:47 PM CDTSevere Thunderstorm WatchSPCBryan, Bulloch, Burke, Candler, Chatham, Columbia and 17 more7 hr
Apr 5, 12:54 PM CDTMesoscale DiscussionSPCBartow, Catoosa, Chattooga, Cherokee, Dade, Dawson and 11 more96 min
Apr 5, 2:37 PM CDTMesoscale DiscussionSPCBurke, Chatham, Columbia, Effingham, Elbert, Franklin and 11 more53 min
Apr 5, 5:35 PM CDTMesoscale DiscussionSPCBryan, Bulloch, Burke, Candler, Chatham, Columbia and 12 more85 min

Nearby

Mesoscale Discussions in Alabama, 2012Mesoscale Discussions in Georgia, 2012Every mesoscale discussion in 2012

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.