Alert archive / Mississippi / Mesoscale Discussions in 2021
Mesoscale Discussion 293
The Storm Prediction Center issued this mesoscale discussion at Mar 27, 2021, 10:45 PM CDT for 4 states. It was in force for 90 min.
The area
The outline as issued.
The facts
- Issued
- Mar 27, 2021, 10:45 PM CDT (03:45 UTC)
- Expired
- Mar 28, 2021, 12:15 AM CDT
- In force
- 90 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 64
All 48 counties
Colbert County, AL, Franklin County, AL, Lauderdale County, AL, Lawrence County, AL, Limestone County, AL, Madison County, AL, Marion County, AL, Morgan County, AL, Winston County, AL, Ashley County, AR, Chicot County, AR, Desha County, AR, Alcorn County, MS, Benton County, MS, Bolivar County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Coahoma County, MS, DeSoto County, MS, Grenada County, MS, Humphreys County, MS, Itawamba County, MS, Lafayette County, MS, Lee County, MS, Leflore County, MS, Marshall County, MS, Montgomery County, MS, Panola County, MS, Pontotoc County, MS, Prentiss County, MS, Quitman County, MS, Sunflower County, MS, Tallahatchie County, MS, Tate County, MS, Tippah County, MS, Tishomingo County, MS, Union County, MS, Washington County, MS, Webster County, MS, Yalobusha County, MS, Fayette County, TN, Giles County, TN, Hardeman County, TN, Hardin County, TN, Lawrence County, TN, McNairy County, TN, Wayne County, TN
The radar
The Columbus AFB radar (KGWX), 87 km from the middle of the area, began a volume at 03:45 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
Little Rock, AR (KLZK), launched 00:00Z, 3.8 hours before the alert went out and 98 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
- 894 J/kg
- Mixed-layer CIN
- -17 J/kg
- Mixed-layer LCL
- 1261 m above ground
- 0-6 km bulk shear
- 79 kt
- 0-1 km storm-relative helicity
- 64 m²/s²
- 0-3 km storm-relative helicity
- 209 m²/s²
- Significant tornado parameter
- 0.7
- Supercell composite
- 8.7
The text
As transmitted.
254
ACUS11 KWNS 280345
SWOMCD
SPC MCD 280345
ALZ000-TNZ000-MSZ000-ARZ000-LAZ000-280515-
Mesoscale Discussion 0293
NWS Storm Prediction Center Norman OK
1045 PM CDT Sat Mar 27 2021
Areas affected...northern Mississippi into northern Alabama and
southern Middle Tennessee
Concerning...Tornado Watch 64...
Valid 280345Z - 280515Z
The severe weather threat for Tornado Watch 64 continues.
SUMMARY...Storms moving across northern Mississippi may affect parts
of northern Alabama and southern Middle Tennessee later tonight,
with damaging wind threat. A brief tornado is also possible.
DISCUSSION...Several organized clusters of storms stretch from
southwest TN and northern MS into southeast AR and northern LA. Some
of these storms are moving east/northeast around 40 kt, and will
approach the AL border by around 06Z. Strong deep-layer shear and
1000-1500 J/kg MLCAPE will support a continued severe threat.
Damaging gusts are most likely given currently observed storm mode,
but veering winds with height and strong southwest winds off the
surface will also support a threat of brief tornadoes associated
with the bows.
..Jewell.. 03/28/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...OHX...BMX...HUN...MEG...JAN...LZK...
LAT...LON 34198647 34098805 33758898 33179025 32869146 33029181
33469186 33779151 34059117 34319046 34709011 34969003
35278927 35338811 35288690 34958633 34438628 34198647SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 27, 11:27 PM CDT | Tornado Watch | SPC | Blount, Colbert, Cullman, DeKalb, Fayette, Franklin and 11 more | 8 hr |
| Mar 28, 1:25 AM CDT | Mesoscale Discussion | SPC | Jackson | 2 hr |
| Mar 28, 1:57 AM CDT | Mesoscale Discussion | SPC | Blount, Colbert, Cullman, DeKalb, Etowah, Fayette and 11 more | 93 min |
| Mar 28, 4:56 AM CDT | Mesoscale Discussion | SPC | Blount, Cullman, DeKalb, Etowah, Marshall, Walker | 94 min |
| Mar 28, 5:10 AM CDT | Severe Thunderstorm Watch | SPC | Bibb, Blount, Calhoun, Cherokee, Clay, Cleburne and 12 more | 5 hr |
| Mar 28, 7:29 AM CDT | Mesoscale Discussion | SPC | Calhoun, Cleburne, Talladega | 91 min |
| Mar 28, 9:14 AM CDT | Mesoscale Discussion | SPC | Autauga, Chambers, Chilton, Clay, Coosa, Dallas and 6 more | 61 min |
| Mar 27, 9:01 PM CDT | Tornado Watch | SPC | Ashley, Chicot, Crittenden, Lee, Phillips, St. Francis | 7 hr |
| Mar 27, 10:30 PM CDT | Mesoscale Discussion | SPC | Union | 2 hr |
| Mar 27, 8:42 PM CDT | Mesoscale Discussion | SPC | Alcorn, Benton, Calhoun, Carroll, Chickasaw, Coahoma and 26 more | 93 min |
| Mar 28, 2:07 AM CDT | Severe Thunderstorm Watch | SPC | Anderson, Bledsoe, Blount, Bradley, Cumberland, Hamilton and 14 more | 6 hr |
Nearby
Mesoscale Discussions in Mississippi, 2021Mesoscale Discussions in Alabama, 2021Mesoscale Discussions in Tennessee, 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.