Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 355
The Storm Prediction Center issued this mesoscale discussion at Apr 9, 2021, 10:47 PM CDT for 5 parishes in Louisiana; 31 counties in Texas. It was in force for 118 min.
The area
The outline as issued.
The facts
- Issued
- Apr 9, 2021, 10:47 PM CDT (03:47 UTC)
- Expired
- Apr 10, 2021, 12:45 AM CDT
- In force
- 118 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 82...83...84
All 36 counties
De Soto Parish, LA, Natchitoches Parish, LA, Red River Parish, LA, Sabine Parish, LA, Vernon Parish, LA, Anderson County, TX, Angelina County, TX, Camp County, TX, Cass County, TX, Cherokee County, TX, Delta County, TX, Franklin County, TX, Gregg County, TX, Harrison County, TX, Henderson County, TX, Hopkins County, TX, Hunt County, TX, Jasper County, TX, Lamar County, TX, Marion County, TX, Morris County, TX, Nacogdoches County, TX, Newton County, TX, Panola County, TX, Rains County, TX, Red River County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX, Smith County, TX, Titus County, TX, Tyler County, TX, Upshur County, TX, Van Zandt County, TX, Wood County, TX
The radar
The Shreveport radar (KSHV), 72 km from the middle of the area, began a volume at 03:49 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 00:00Z, 3.8 hours before the alert went out and 81 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
- 148 J/kg
- Mixed-layer CIN
- -321 J/kg
- Mixed-layer LCL
- 2441 m above ground
- 0-6 km bulk shear
- 52 kt
- 0-1 km storm-relative helicity
- 329 m²/s²
- 0-3 km storm-relative helicity
- 421 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
871
ACUS11 KWNS 100347
SWOMCD
SPC MCD 100347
LAZ000-TXZ000-OKZ000-100545-
Mesoscale Discussion 0355
NWS Storm Prediction Center Norman OK
1047 PM CDT Fri Apr 09 2021
Areas affected...eastern Texas into western Louisiana
Concerning...Severe Thunderstorm Watch 82...83...84...
Valid 100347Z - 100545Z
The severe weather threat for Severe Thunderstorm Watch 82, 83, 84
continues.
SUMMARY...Severe hail and wind remain possible across parts of east
Texas into western Louisiana.
DISCUSSION...A cold front continues to surge southeast toward the
Arklatex and through the Metroplex. Meanwhile, outflow-cooled air
remains over much of AR, northeast TX, and northern LA. Strong
instability remains along the I-35 corridor, and though surface
temperatures are cooling, strong elevated instability exists across
the region, including atop the rain-cooled air mass.
Isolated cells over east-central TX may persist for some time given
the favorable downstream air mass, with large hail and perhaps
damaging gusts. To the north, the squall line along the front has
struggled to grow further, but potential remains given the strength
of the lift. Elevated hail is possible north of the outflow
boundary, with severe wind gusts more likely into the warmer air
farther west.
..Jewell.. 04/10/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LCH...SHV...TSA...HGX...FWD...
LAT...LON 32249626 33239629 33619587 33939526 33899487 33239428
32449382 32059315 31749283 31329276 31249276 31159302
30699379 30709445 31549565 31559563 32249626SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 9, 10:25 PM CDT | Severe Thunderstorm Watch | SPC | Avoyelles, Catahoula, Concordia, East Baton Rouge, East Feliciana, Evangeline and 10 more | 6 hr |
| Apr 9, 11:00 PM CDT | Mesoscale Discussion | SPC | Acadia, Allen, Ascension, Avoyelles, Concordia, East Baton Rouge and 16 more | 2 hr |
| Apr 10, 12:16 AM CDT | Tornado Watch | SPC | Acadia, Allen, Ascension, Assumption, Avoyelles, East Baton Rouge and 19 more | 7 hr |
| Apr 10, 12:52 AM CDT | Severe Thunderstorm Watch | SPC | Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 11 more | 3 hr |
| Apr 9, 8:21 PM CDT | Mesoscale Discussion | SPC | Bosque, Collin, Coryell, Dallas, Delta, Ellis and 17 more | 3 hr |
| Apr 9, 8:44 PM CDT | Severe Thunderstorm Watch | SPC | Bowie, Camp, Cass, Franklin, Morris, Red River and 3 more | 5 hr |
Nearby
Mesoscale Discussions in Texas, 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.