Alert archive / Alabama / Mesoscale Discussions in 2021
Mesoscale Discussion 252
The Storm Prediction Center issued this mesoscale discussion at Mar 25, 2021, 10:12 AM CDT for 4 states. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- Mar 25, 2021, 10:12 AM CDT (15:12 UTC)
- Expired
- Mar 25, 2021, 12:45 PM CDT
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...tornado watch likely
- Chance of a watch
- 95%
All 38 counties
Bibb County, AL, Blount County, AL, Colbert County, AL, Cullman County, AL, DeKalb County, AL, Etowah County, AL, Fayette County, AL, Franklin County, AL, Greene County, AL, Hale County, AL, Jackson County, AL, Jefferson County, AL, Lamar County, AL, Lauderdale County, AL, Lawrence County, AL, Limestone County, AL, Madison 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, Tuscaloosa County, AL, Walker County, AL, Winston County, AL, Dade County, GA, Kemper County, MS, Lauderdale County, MS, Lowndes County, MS, Noxubee County, MS, Franklin County, TN, Giles County, TN, Lincoln County, TN, Marion County, TN, Moore County, TN
The radar
The Birmingham radar (KBMX), 90 km from the middle of the area, began a volume at 15:11 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, 3.2 hours before the alert went out and 89 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.
- Mixed-layer CAPE
- 54 J/kg
- Mixed-layer CIN
- -239 J/kg
- Mixed-layer LCL
- 507 m above ground
- 0-6 km bulk shear
- 65 kt
- 0-1 km storm-relative helicity
- 613 m²/s²
- 0-3 km storm-relative helicity
- 713 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 5.6
The text
As transmitted.
747
ACUS11 KWNS 251513
SWOMCD
SPC MCD 251512
TNZ000-GAZ000-ALZ000-MSZ000-251745-
Mesoscale Discussion 0252
NWS Storm Prediction Center Norman OK
1012 AM CDT Thu Mar 25 2021
Areas affected...central and northern Mississippi and
Alabama...parts of southern Tennessee
Concerning...Severe potential...Tornado Watch likely
Valid 251512Z - 251745Z
Probability of Watch Issuance...95 percent
SUMMARY...Ongoing storms from Mississippi into Alabama may
consolidate into supercells through midday with developing tornado
threat. A tornado watch is likely by early afternoon.
DISCUSSION...Ongoing activity over eastern MS and into AL has been
elevated for much of the morning, but cells now extend southwest of
the warm front which is situated from from northern MS into central
AL. Radar trends show that cells within these areas have acquired
rotation as they attempt to transition from elevated to surface
based. This may happen over the next couple hours as temperatures
warm into the 70s F with the warm front lifting north, maximizing
effective SRH. Therefore, it is possible that these cells develop a
tornado threat over the next few hours. 0-1 km SRH of 300-400 m2/s2
along the warm front will favor strong tornadoes as the stronger
instability develops into the warm advection zone.
..Jewell/Hart.. 03/25/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MRX...FFC...OHX...BMX...HUN...MOB...MEG...JAN...
LAT...LON 34558543 33158671 32708716 32228802 32168845 32328874
32788873 33558850 34138830 34958767 35408680 35488638
35318581 35118545 34828537 34558543SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 24, 9:25 PM CDT | Mesoscale Discussion | SPC | Baldwin, Mobile, Washington | 65 min |
| Mar 25, 9:02 AM CDT | Mesoscale Discussion | SPC | Blount, Calhoun, Cherokee, Cleburne, Colbert, Cullman and 21 more | 118 min |
| Mar 25, 10:58 AM CDT | Mesoscale Discussion | SPC | Colbert, Fayette, Franklin, Lamar, Lawrence, Marion and 2 more | 3 hr |
| Mar 25, 11:26 AM CDT | Tornado Watch | SPC | Autauga, Bibb, Blount, Calhoun, Chambers, Cherokee and 39 more | 9 hr |
| Mar 25, 12:28 PM CDT | Mesoscale Discussion | SPC | Bibb, Calhoun, Clay, Cleburne, Shelby, Talladega | 2 hr |
| Mar 25, 1:24 PM CDT | Mesoscale Discussion | SPC | Colbert, Fayette, Franklin, Greene, Lamar, Lawrence and 4 more | 2 hr |
| Mar 25, 3:45 PM CDT | Mesoscale Discussion | SPC | Bibb, Chilton, Choctaw, Dallas, Greene, Hale and 8 more | 2 hr |
| Mar 25, 4:45 PM CDT | Mesoscale Discussion | SPC | Bibb, Chilton, Coosa, Perry, Shelby, Talladega | 60 min |
| Mar 25, 5:45 PM CDT | Mesoscale Discussion | SPC | Clay, Randolph | 60 min |
| Mar 25, 4:31 PM CDT | Mesoscale Discussion | SPC | Banks, Catoosa, Cherokee, Dawson, Fannin, Forsyth and 13 more | 119 min |
| Mar 25, 6:46 PM CDT | Tornado Watch | SPC | Banks, Barrow, Bartow, Carroll, Catoosa, Chattooga and 41 more | 8 hr |
| Mar 25, 11:00 AM CDT | Mesoscale Discussion | SPC | Hancock, Harrison, Pearl River, Stone | 2 hr |
| Mar 25, 2:29 PM CDT | Mesoscale Discussion | SPC | Alcorn | 2 hr |
| Mar 25, 3:48 PM CDT | Tornado Watch | SPC | Alcorn | 7 hr |
| Mar 25, 2:33 PM CDT | Mesoscale Discussion | SPC | Dyer, Henry, Lake, Obion, Weakley | 117 min |
| Mar 25, 5:52 PM CDT | Mesoscale Discussion | SPC | Benton, Carroll, Cheatham, Chester, Crockett, Davidson and 24 more | 83 min |
Nearby
Mesoscale Discussions in Alabama, 2021Mesoscale Discussions in Tennessee, 2021Mesoscale Discussions in Mississippi, 2021Every mesoscale discussion in 2021
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.