Alert archive / Louisiana / Mesoscale Discussions in 2021
Mesoscale Discussion 348
The Storm Prediction Center issued this mesoscale discussion at Apr 9, 2021, 5:19 PM CDT for Ashley County, Arkansas; 16 parishes in Louisiana; 6 counties in Texas. It was in force for 116 min.
The area
The outline as issued.
The facts
- Issued
- Apr 9, 2021, 5:19 PM CDT (22:19 UTC)
- Expired
- Apr 9, 2021, 7:15 PM CDT
- In force
- 116 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 76
All 23 counties
Ashley County, AR, Bienville Parish, LA, Caldwell Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, Lincoln Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Union Parish, LA, Winn Parish, LA, Angelina County, TX, Cherokee County, TX, Nacogdoches County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX
The radar
The Shreveport radar (KSHV), 51 km from the middle of the area, began a volume at 22:22 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
Shreveport, LA (KSHV), launched 12:00Z, 10.3 hours before the alert went out and 48 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
- 928 J/kg
- Mixed-layer CIN
- -310 J/kg
- Mixed-layer LCL
- 1043 m above ground
- 0-6 km bulk shear
- 37 kt
- 0-1 km storm-relative helicity
- 6 m²/s²
- 0-3 km storm-relative helicity
- 61 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
209
ACUS11 KWNS 092219
SWOMCD
SPC MCD 092219
LAZ000-ARZ000-TXZ000-100015-
Mesoscale Discussion 0348
NWS Storm Prediction Center Norman OK
0519 PM CDT Fri Apr 09 2021
Areas affected...eastern Texas...northern Louisiana
Concerning...Severe Thunderstorm Watch 76...
Valid 092219Z - 100015Z
The severe weather threat for Severe Thunderstorm Watch 76
continues.
SUMMARY...A threat of large hail will continue this evening, with
tornado or damaging wind potential late. A new severe thunderstorm
watch coordinated with WFO Shreveport will replace parts of watch 76
shortly.
DISCUSSION...An MCS continues to move east across southeast AR, with
an outflow boundary trailing southwestward into northern LA and into
northeast TX. Scattered storms persist mainly on the cool side of
this outflow, though storms over east TX are close to the warm side
of the boundary.
Despite somewhat disorganized storm structure as of 22Z, all these
cells will have large hail potential due to steep lapse rates aloft.
As the outflow modifies over the next several hours, a better
tornado risk is expected along and on the warm side of the outflow
boundary, where surface observations show winds gusting out of the
south.
..Jewell.. 04/09/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...JAN...LCH...SHV...HGX...FWD...
LAT...LON 31749558 32029455 32829311 33239190 33179159 32969150
32749145 32039157 31529246 31079442 31279535 31509565
31749558SPC 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, 3:10 PM CDT | Mesoscale Discussion | SPC | Arkansas, Ashley, Bradley, Chicot, Cleveland, Desha and 5 more | 95 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, 5:32 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 8, 9:58 PM CDT | Mesoscale Discussion | SPC | Anderson, Brazos, Cherokee, Freestone, Grimes, Henderson and 7 more | 2 hr |
| Apr 9, 3:59 PM CDT | Mesoscale Discussion | SPC | Bastrop, Bell, Blanco, Bosque, Burnet, Caldwell and 14 more | 2 hr |
| Apr 9, 4:27 PM CDT | Severe Thunderstorm Watch | SPC | Anderson, Bell, Bosque, Collin, Cooke, Coryell and 26 more | 9 hr |
Nearby
Mesoscale Discussions in Louisiana, 2021Mesoscale Discussions in Texas, 2021Mesoscale Discussions in Arkansas, 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.