Alert archive / Louisiana / Severe Thunderstorm Watches in 2021
Severe Thunderstorm Watch 160
The Storm Prediction Center issued this severe thunderstorm watch at May 9, 2021, 5:45 PM CDT for 13 parishes in Louisiana; Jasper County, Newton County, Tyler County, Texas. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- May 9, 2021, 5:45 PM CDT (22:45 UTC)
- Expired
- May 10, 2021, 1:00 AM CDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
Counties Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Caldwell Parish, LA, Evangeline Parish, LA, Grant Parish, LA, LaSalle Parish, LA, Natchitoches Parish, LA, Rapides Parish, LA, Sabine Parish, LA, Saint Landry Parish, LA, Vernon Parish, LA, Winn Parish, LA, Jasper County, TX, Newton County, TX, Tyler County, TX
The radar
The Ft Polk radar (KPOE), 35 km from the middle of the area, began a volume at 22:45 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.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 20%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 60%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 60%
- One or more hailstones of 2 inches or more
- 60%
- Six or more combined severe hail and wind reports
- 95%
Warnings issued inside it
5 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 9, 6:23 PM CDT | Severe Thunderstorm Warning | SHV | Sabine | 67 min |
| May 9, 6:31 PM CDT | Severe Thunderstorm Warning | LCH | Jasper, Newton, Tyler | 59 min |
| May 9, 6:58 PM CDT | Flash Flood Warning | SHV | Sabine | 10 hr |
| May 9, 7:22 PM CDT | Severe Thunderstorm Warning | LCH | Beauregard, Vernon | 53 min |
| May 9, 7:22 PM CDT | Severe Thunderstorm Warning | SHV | Grant, Natchitoches, Sabine | 53 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Lake Charles Mun, LA (KLCH), launched 12:00Z, 10.8 hours before the alert went out and 135 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
- 1028 J/kg
- Mixed-layer CIN
- -148 J/kg
- Mixed-layer LCL
- 575 m above ground
- 0-6 km bulk shear
- 29 kt
- 0-1 km storm-relative helicity
- 105 m²/s²
- 0-3 km storm-relative helicity
- 304 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 1.4
The text
As transmitted.
270
WWUS20 KWNS 092240
SEL0
SPC WW 092240
LAZ000-TXZ000-100600-
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 160
NWS Storm Prediction Center Norman OK
545 PM CDT Sun May 9 2021
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Central Louisiana
Southeast Texas
* Effective this Sunday afternoon and Monday morning from 545 PM
until 100 AM CDT.
* Primary threats include...
Scattered large hail and isolated very large hail events to 2
inches in diameter likely
Scattered damaging wind gusts to 70 mph likely
A tornado or two possible
SUMMARY...A cluster of intense thunderstorms over eastern Texas will
move eastward this evening across the watch area. The stronger
cores will pose a risk of hail and damaging wind gusts.
The severe thunderstorm watch area is approximately along and 50
statute miles north and south of a line from 65 miles west of Fort
Polk LA to 30 miles east of Alexandria LA. For a complete depiction
of the watch see the associated watch outline update (WOUS64 KWNS
WOU0).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 157...WW 158...WW 159...
AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
27030.
...HartSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 9, 12:14 PM CDT | Mesoscale Discussion | SPC | Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 13 more | 91 min |
| May 9, 1:14 PM CDT | Severe Thunderstorm Watch | SPC | Bienville, Bossier, Caddo, Claiborne, De Soto, East Carroll and 9 more | 8 hr |
| May 9, 3:42 PM CDT | Mesoscale Discussion | SPC | Bossier, Caddo, Claiborne, Webster | 93 min |
| May 9, 3:53 PM CDT | Mesoscale Discussion | SPC | Madison, Tensas | 2 hr |
| May 9, 5:41 PM CDT | Mesoscale Discussion | SPC | Bienville, Bossier, Caddo, Caldwell, Catahoula, Claiborne and 22 more | 2 hr |
| May 9, 1:41 PM CDT | Mesoscale Discussion | SPC | Anderson, Bell, Blanco, Brazos, Burleson, Burnet and 27 more | 94 min |
| May 9, 3:01 PM CDT | Severe Thunderstorm Watch | SPC | Anderson, Bell, Blanco, Bosque, Burnet, Comal and 32 more | 7 hr |
Nearby
Severe Thunderstorm Watches in Louisiana, 2021Severe Thunderstorm Watches in Texas, 2021Every severe thunderstorm watch 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.