Alert archive / Mississippi / Mesoscale Discussions in 2021
Mesoscale Discussion 253
The Storm Prediction Center issued this mesoscale discussion at Mar 25, 2021, 10:58 AM CDT for 8 counties in Alabama; Madison Parish, Louisiana; 41 counties in Mississippi. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- Mar 25, 2021, 10:58 AM CDT (15:58 UTC)
- Expired
- Mar 25, 2021, 1:30 PM CDT
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...tornado watch likely
- Chance of a watch
- 95%
All 50 counties
Colbert County, AL, Fayette County, AL, Franklin County, AL, Lamar County, AL, Lawrence County, AL, Marion County, AL, Pickens County, AL, Winston County, AL, Madison Parish, LA, Alcorn County, MS, Attala County, MS, Benton County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Claiborne County, MS, Clay County, MS, Grenada County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Itawamba County, MS, Kemper County, MS, Lafayette County, MS, Leake County, MS, Lee County, MS, Leflore County, MS, Lowndes County, MS, Madison County, MS, Monroe County, MS, Montgomery County, MS, Neshoba County, MS, Noxubee County, MS, Oktibbeha County, MS, Pontotoc County, MS, Prentiss County, MS, Rankin County, MS, Scott County, MS, Sharkey County, MS, Tallahatchie County, MS, Tippah County, MS, Tishomingo County, MS, Union County, MS, Warren County, MS, Webster County, MS, Winston County, MS, Yalobusha County, MS, Yazoo County, MS
The radar
The Columbus AFB radar (KGWX), 100 km from the middle of the area, began a volume at 15:59 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
Jackson, MS (KJAN), launched 12:00Z, 4.0 hours before the alert went out and 150 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
- 1775 J/kg
- Mixed-layer CIN
- -31 J/kg
- Mixed-layer LCL
- 506 m above ground
- 0-6 km bulk shear
- 51 kt
- 0-1 km storm-relative helicity
- 352 m²/s²
- 0-3 km storm-relative helicity
- 473 m²/s²
- Significant tornado parameter
- 4.6
- Supercell composite
- 21.9
The text
As transmitted.
042
ACUS11 KWNS 251559
SWOMCD
SPC MCD 251558
ALZ000-MSZ000-LAZ000-251830-
Mesoscale Discussion 0253
NWS Storm Prediction Center Norman OK
1058 AM CDT Thu Mar 25 2021
Areas affected...central and northern Mississippi...parts of
southwest Tennessee...northwest Alabama
Concerning...Severe potential...Tornado Watch likely
Valid 251558Z - 251830Z
Probability of Watch Issuance...95 percent
SUMMARY...Storms are expected to form over the next couple hours
over central and western Mississippi. Supercells are likely, with
tornado threat increasing as cells mature and move northeast toward
Alabama. Watch will be issues soon.
DISCUSSION...Visible imagery and surface obs indicate the air mass
continues to destabilize with areas of heating, as temperatures rise
into the mid 70s F over the warm sector. This is sufficiently warm
for surface-based parcels. Indications are that cells may develop
both ahead of the cold front due to a very moist warm sector, and
along the front itself. Deep-layer shear is expected to strengthen
storms, which will gain intensity and tornado potential as they
mature and continue northeastward across MS and into AL. The threat
may extend into southern TN as well, once the warm front lifts
there.
..Jewell/Hart.. 03/25/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BMX...HUN...MEG...JAN...
LAT...LON 34518723 33648755 32818831 32098988 31999016 31929073
31999125 32249135 32749119 33559059 34488978 34818934
34908869 34928788 34798752 34518723SPC 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, 10:12 AM CDT | Mesoscale Discussion | SPC | Bibb, Blount, Colbert, Cullman, DeKalb, Etowah and 22 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, 11:00 AM CDT | Mesoscale Discussion | SPC | Ascension, Assumption, East Baton Rouge, Livingston, Orleans, Saint Charles and 6 more | 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 |
Nearby
Mesoscale Discussions in Mississippi, 2021Mesoscale Discussions in Alabama, 2021Mesoscale Discussions in Louisiana, 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.