Alert archive / Mississippi / Mesoscale Discussions in 2021
Mesoscale Discussion 344
The Storm Prediction Center issued this mesoscale discussion at Apr 9, 2021, 3:10 PM CDT for 11 counties in Arkansas; 8 parishes in Louisiana; 18 counties in Mississippi. It was in force for 95 min.
The area
The outline as issued.
The facts
- Issued
- Apr 9, 2021, 3:10 PM CDT (20:10 UTC)
- Expired
- Apr 9, 2021, 4:45 PM CDT
- In force
- 95 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 76
All 37 counties
Arkansas County, AR, Ashley County, AR, Bradley County, AR, Chicot County, AR, Cleveland County, AR, Desha County, AR, Drew County, AR, Lee County, AR, Lincoln County, AR, Phillips County, AR, Union County, AR, Claiborne Parish, LA, East Carroll Parish, LA, Lincoln Parish, LA, Morehouse Parish, LA, Ouachita Parish, LA, Richland Parish, LA, Union Parish, LA, West Carroll Parish, LA, Bolivar County, MS, Carroll County, MS, Coahoma County, MS, DeSoto County, MS, Grenada County, MS, Humphreys County, MS, Issaquena County, MS, Lafayette County, MS, Leflore County, MS, Panola County, MS, Quitman County, MS, Sharkey County, MS, Sunflower County, MS, Tallahatchie County, MS, Tate County, MS, Tunica County, MS, Washington County, MS, Yalobusha County, MS
The radar
The Little Rock radar (KLZK), 162 km from the middle of the area, began a volume at 20:12 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, 8.2 hours before the alert went out and 186 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
- 1659 J/kg
- Mixed-layer CIN
- -54 J/kg
- Mixed-layer LCL
- 787 m above ground
- 0-6 km bulk shear
- 41 kt
- 0-1 km storm-relative helicity
- 127 m²/s²
- 0-3 km storm-relative helicity
- 150 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 4.4
The text
As transmitted.
717
ACUS11 KWNS 092011
SWOMCD
SPC MCD 092010
MSZ000-TNZ000-ARZ000-LAZ000-092145-
Mesoscale Discussion 0344
NWS Storm Prediction Center Norman OK
0310 PM CDT Fri Apr 09 2021
Areas affected...Parts of southern/eastern Arkansas...northern
Louisiana...northwestern Mississippi and adjacent western Tennessee
Concerning...Severe Thunderstorm Watch 76...
Valid 092010Z - 092145Z
The severe weather threat for Severe Thunderstorm Watch 76
continues.
SUMMARY...An increasingly organized cluster of severe thunderstorms
is expected to continue to evolve while propagating
east-northeastward into the lower Mississippi Valley/Mid South
region through 4-6 PM. A new severe weather watch will be needed
downstream with the next hour or so.
DISCUSSION...Convection has taken root within the moderate to
strongly unstable boundary layer east of Texarkana, with rapid
intensification ongoing. Further upscale growth and organization
seems likely through the next few hours, given the downstream
environment and continuing southeasterly inflow, within favorably
sheared, 30-40 kt deep-layer ambient mean flow. Based on a
continuing 35 kt forward propagation, this activity appears likely
to spread east of the Mississippi River into the Mississippi Delta
region by 22Z, likely accompanied by continuing potential for
frequent cloud to ground lightning, large, possibly damaging, hail
and increasing potential for a developing swath of severe wind
gusts.
..Kerr.. 04/09/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MEG...JAN...LZK...SHV...
LAT...LON 33509233 33879223 34659105 35079020 34568940 33698962
32599061 32379179 32349319 32919307 33509233SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 9, 9:49 AM CDT | Mesoscale Discussion | SPC | Hempstead, Howard, Lafayette, Little River, Miller, Pike and 1 more | 116 min |
| Apr 9, 12:07 PM CDT | Severe Thunderstorm Watch | SPC | Arkansas, Bradley, Calhoun, Clark, Cleveland, Columbia and 20 more | 6 hr |
| Apr 9, 1:25 PM CDT | Mesoscale Discussion | SPC | Arkansas, Ashley, Bradley, Chicot, Desha, Drew and 5 more | 95 min |
| Apr 9, 2:50 PM CDT | Mesoscale Discussion | SPC | Baxter, Benton, Boone, Carroll, Clay, Cleburne and 18 more | 85 min |
| Apr 9, 3:13 PM CDT | Severe Thunderstorm Watch | SPC | Baxter, Fulton, Izard, Lawrence, Marion, Randolph and 1 more | 7 hr |
| Apr 9, 3:14 PM CDT | Mesoscale Discussion | SPC | Benton, Crawford, Franklin, Polk, Scott, Sebastian and 2 more | 61 min |
| Apr 9, 3:42 PM CDT | Severe Thunderstorm Watch | SPC | Ashley, Chicot, Clay, Craighead, Crittenden, Cross and 6 more | 7 hr |
| Apr 9, 5:19 PM CDT | Mesoscale Discussion | SPC | Ashley | 116 min |
| Apr 9, 5:32 PM CDT | Severe Thunderstorm Watch | SPC | Columbia, Union | 7 hr |
| Apr 9, 6:34 PM CDT | Mesoscale Discussion | SPC | Benton, Carroll, Crawford, Madison, Washington | 116 min |
| Apr 9, 2:49 AM CDT | Mesoscale Discussion | SPC | Jefferson, Plaquemines, Saint Bernard | 2 hr |
| Apr 9, 6:14 PM CDT | Mesoscale Discussion | SPC | Caldwell, East Carroll, Franklin, Madison, Morehouse, Ouachita and 2 more | 3 hr |
| Apr 9, 11:44 AM CDT | Mesoscale Discussion | SPC | Clay, Kemper, Lauderdale, Lowndes, Monroe, Neshoba and 3 more | 2 hr |
| Apr 9, 5:54 PM CDT | Mesoscale Discussion | SPC | Kemper, Lauderdale, Lowndes, Noxubee | 96 min |
Nearby
Mesoscale Discussions in Mississippi, 2021Mesoscale Discussions in Arkansas, 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.