Alert archive / Alabama / Mesoscale Discussions in 2021
Mesoscale Discussion 308
The Storm Prediction Center issued this mesoscale discussion at Mar 31, 2021, 10:57 AM CDT for 23 counties in Alabama; 15 counties in Georgia; 10 counties in Mississippi. It was in force for 93 min.
The area
The outline as issued.
The facts
- Issued
- Mar 31, 2021, 10:57 AM CDT (15:57 UTC)
- Expired
- Mar 31, 2021, 12:30 PM CDT
- In force
- 93 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 60%
All 48 counties
Autauga County, AL, Barbour County, AL, Bullock County, AL, Butler County, AL, Chambers County, AL, Choctaw County, AL, Clarke County, AL, Conecuh County, AL, Crenshaw County, AL, Dallas County, AL, Elmore County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Marengo County, AL, Monroe County, AL, Montgomery County, AL, Perry County, AL, Pike County, AL, Russell County, AL, Tallapoosa County, AL, Washington County, AL, Wilcox County, AL, Chattahoochee County, GA, Coweta County, GA, Fayette County, GA, Harris County, GA, Lamar County, GA, Marion County, GA, Meriwether County, GA, Muscogee County, GA, Pike County, GA, Spalding County, GA, Stewart County, GA, Talbot County, GA, Taylor County, GA, Troup County, GA, Upson County, GA, Clarke County, MS, Covington County, MS, Forrest County, MS, Greene County, MS, Jasper County, MS, Jefferson Davis County, MS, Jones County, MS, Lamar County, MS, Perry County, MS, Wayne County, MS
The radar
The Maxwell AFB radar (KMXX), 92 km from the middle of the area, began a volume at 15:58 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, 4.0 hours before the alert went out and 102 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
- 455 J/kg
- Mixed-layer CIN
- -3 J/kg
- Mixed-layer LCL
- 527 m above ground
- 0-6 km bulk shear
- 44 kt
- 0-1 km storm-relative helicity
- 273 m²/s²
- 0-3 km storm-relative helicity
- 283 m²/s²
- Significant tornado parameter
- 0.6
- Supercell composite
- 3.5
The text
As transmitted.
573
ACUS11 KWNS 311558
SWOMCD
SPC MCD 311557
GAZ000-ALZ000-MSZ000-311730-
Mesoscale Discussion 0308
NWS Storm Prediction Center Norman OK
1057 AM CDT Wed Mar 31 2021
Areas affected...southeast Mississippi through south central Alabama
and central Georgia
Concerning...Severe potential...Watch possible
Valid 311557Z - 311730Z
Probability of Watch Issuance...60 percent
SUMMARY...Thunderstorms may become capable of producing mainly
isolated damaging wind and hail this afternoon. A brief tornado also
cannot be ruled out.
DISCUSSION...As of mid day thunderstorms continue developing along a
convective outflow boundary that extends from northern GA southwest
through central AL and into southern MS. This boundary will continue
moving slowly southeast the remainder of the afternoon. Satellite
imagery indicates partial clearing in the warm sector where
dewpoints are generally in the mid to upper 60s F but with low 60s
with eastward extent into GA. The 12Z RAOB data show weak mid level
lapse rates, but as the moist boundary layer destabilizes, MLCAPE
will increase to around 500 J/kg across central GA and up to 1500
J/kg along southern portions of the Gulf Coast states. While winds
in the surface to 700 mb layer will remain weak to modest, mid-upper
flow will gradually increase as the upstream trough amplifies,
supporting effective bulk shear from 50 to 55 kt. This suggests a
few organized storms may occur including bowing segments and
possibly some supercell structures with isolated damaging wind the
primary threat, though some hail will also accompany the stronger
updrafts.
..Dial/Grams.. 03/31/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FFC...TAE...BMX...MOB...JAN...
LAT...LON 31469020 32038914 32718762 32868653 33088543 33458477
33528428 32928391 32328426 31968501 31618618 31318734
31058918 31469020SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 31, 1:55 AM CDT | Mesoscale Discussion | SPC | Blount, Cullman, Fayette, Franklin, Lamar, Lawrence and 5 more | 2 hr |
| Mar 31, 11:19 AM CDT | Severe Thunderstorm Watch | SPC | Autauga, Barbour, Bibb, Bullock, Butler, Chambers and 23 more | 6 hr |
| Mar 31, 2:15 PM CDT | Mesoscale Discussion | SPC | Barbour, Bullock, Butler, Clarke, Conecuh, Crenshaw and 4 more | 90 min |
| Mar 31, 2:52 PM CDT | Mesoscale Discussion | SPC | Baldwin, Coffee, Covington, Dale, Escambia, Geneva and 2 more | 53 min |
| Mar 31, 3:12 PM CDT | Severe Thunderstorm Watch | SPC | Baldwin, Coffee, Covington, Dale, Escambia, Geneva and 3 more | 4 hr |
| Mar 31, 4:50 PM CDT | Mesoscale Discussion | SPC | Coffee, Dale, Houston | 115 min |
| Mar 31, 5:24 PM CDT | Mesoscale Discussion | SPC | Bryan, Bulloch, Burke, Candler, Chatham, Effingham and 11 more | 2 hr |
| Mar 30, 9:55 PM CDT | Mesoscale Discussion | SPC | Bolivar, Calhoun, Carroll, Grenada, Humphreys, Lafayette and 11 more | 2 hr |
Nearby
Mesoscale Discussions in Alabama, 2021Mesoscale Discussions in Georgia, 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.