Alert archive / Louisiana / Mesoscale Discussions in 2021
Mesoscale Discussion 1914
The Storm Prediction Center issued this mesoscale discussion at Oct 27, 2021, 10:59 AM CDT for Beauregard Parish, Vernon Parish, Louisiana; Newton County, Texas. It was in force for 91 min.
The area
The outline as issued.
The facts
- Issued
- Oct 27, 2021, 10:59 AM CDT (15:59 UTC)
- Expired
- Oct 27, 2021, 12:30 PM CDT
- In force
- 91 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 540
Counties Beauregard Parish, LA, Vernon Parish, LA, Newton County, TX
The radar
The Ft Polk radar (KPOE), 39 km from the middle of the area, began a volume at 16:02 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 nearest sounding before it
Lake Charles Mun, LA (KLCH), launched 12:00Z, 4.0 hours before the alert went out and 86 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
- 1422 J/kg
- Mixed-layer CIN
- -5 J/kg
- Mixed-layer LCL
- 604 m above ground
- 0-6 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- 160 m²/s²
- 0-3 km storm-relative helicity
- 255 m²/s²
- Significant tornado parameter
- 1.1
- Supercell composite
- 7.1
The text
As transmitted.
840 ACUS11 KWNS 271600 SWOMCD SPC MCD 271559 LAZ000-TXZ000-271730- Mesoscale Discussion 1914 NWS Storm Prediction Center Norman OK 1059 AM CDT Wed Oct 27 2021 Areas affected...southeast Texas through southwest Louisiana Concerning...Tornado Watch 540... Valid 271559Z - 271730Z The severe weather threat for Tornado Watch 540 continues. SUMMARY...Threat for a few tornadoes (a couple of which could be strong) remains relatively high across southeast TX into southwest LA through at least 18Z. DISCUSSION...Supercell with a history of tornadoes has crossed into southwest LA and will remain in a favorable environment for additional tornadoes next couple hours. Other semi-discrete storms farther west in southeast TX might also become better organized, but some of this activity is being overtaken by the squall line. A couple storms are developing in closer proximity to the warm front over southwest LA, and might evolve into supercells as they continue northeast. Low-level hodographs remain large within a low LCL and moderately unstable environment, suggesting the threat for tornadoes will persist next couple hours, especially with discrete or semi-discrete storms in warm sector and in proximity to the warm front. Otherwise, isolated strong to damaging wind gusts and brief QLCS tornadoes remain possible with embedded organized structures in the squall line. ..Dial.. 10/27/2021 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LCH...SHV... LAT...LON 31319310 31019262 30349302 30159390 31219375 31319310
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 27, 7:36 AM CDT | Mesoscale Discussion | SPC | Acadia, Beauregard, Calcasieu, Cameron, Iberia, Jefferson Davis and 4 more | 84 min |
| Oct 27, 7:55 AM CDT | Tornado Watch | SPC | Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 13 more | 9 hr |
| Oct 27, 9:44 AM CDT | Mesoscale Discussion | SPC | Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 7 more | 2 hr |
| Oct 27, 10:08 AM CDT | Tornado Watch | SPC | Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 6 more | 5 hr |
| Oct 27, 12:50 PM CDT | Mesoscale Discussion | SPC | Acadia, Ascension, Assumption, Avoyelles, Concordia, East Baton Rouge and 24 more | 85 min |
| Oct 27, 12:52 PM CDT | Mesoscale Discussion | SPC | Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 7 more | 83 min |
| Oct 27, 1:53 PM CDT | Tornado Watch | SPC | Ascension, Assumption, Catahoula, Concordia, East Baton Rouge, East Feliciana and 18 more | 8 hr |
| Oct 27, 3:25 PM CDT | Mesoscale Discussion | SPC | Ascension, Assumption, East Baton Rouge, East Feliciana, Iberville, Jefferson and 13 more | 95 min |
| Oct 27, 5:13 PM CDT | Mesoscale Discussion | SPC | Orleans, Saint Bernard, Saint John the Baptist, Saint Tammany, Tangipahoa, Washington | 2 hr |
| Oct 26, 7:23 PM CDT | Severe Thunderstorm Watch | SPC | Archer, Baylor, Brown, Callahan, Clay, Coke and 45 more | 8 hr |
| Oct 26, 9:37 PM CDT | Mesoscale Discussion | SPC | Archer, Baylor, Callahan, Clay, Coke, Coleman and 26 more | 83 min |
| Oct 27, 1:32 AM CDT | Severe Thunderstorm Watch | SPC | Anderson, Bastrop, Bell, Bexar, Blanco, Bosque and 48 more | 6 hr |
| Oct 27, 1:59 AM CDT | Mesoscale Discussion | SPC | Collin, Cooke, Dallas, Denton, Ellis, Grayson and 8 more | 91 min |
| Oct 27, 5:13 AM CDT | Mesoscale Discussion | SPC | Atascosa, Austin, Bastrop, Bexar, Brazos, Burleson and 22 more | 2 hr |
| Oct 27, 9:08 AM CDT | Mesoscale Discussion | SPC | Hardin, Jasper, Jefferson, Newton, Orange, Tyler | 97 min |
Nearby
Mesoscale Discussions in Louisiana, 2021Mesoscale Discussions in Texas, 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.