Alert archive / Louisiana / Severe Thunderstorm Watches in 2020
Severe Thunderstorm Watch 155
The Storm Prediction Center issued this severe thunderstorm watch at Apr 29, 2020, 12:48 AM CDT for Ashley County, Chicot County, Arkansas; 18 parishes in Louisiana; 15 counties in Mississippi. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 29, 2020, 12:48 AM CDT (05:48 UTC)
- Expired
- Apr 29, 2020, 4:47 AM CDT
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 0.5 in
- Strongest gust expected
- 60 kt
All 35 counties
Ashley County, AR, Chicot County, AR, Caldwell Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Carroll Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Richland Parish, LA, Tensas Parish, LA, Union Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Adams County, MS, Bolivar County, MS, Carroll County, MS, Claiborne County, MS, Grenada County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Jefferson County, MS, Leflore County, MS, Sharkey County, MS, Sunflower County, MS, Warren County, MS, Washington County, MS, Yazoo County, MS
The radar
The Jackson/Brandon,MS radar (KDGX), 107 km from the middle of the area, began a volume at 05:51 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
- 10%
- One or more EF2 to EF5 tornadoes
- 5%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 5%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
4 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 29, 12:51 AM CDT | Severe Thunderstorm Warning | SHV | Claiborne, Lincoln, Union | 54 min |
| Apr 29, 1:34 AM CDT | Severe Thunderstorm Warning | SHV | Bienville, De Soto, Jackson, Natchitoches, Red River, Sabine and 1 more | 56 min |
| Apr 29, 1:37 AM CDT | Severe Thunderstorm Warning | SHV | Caldwell, Jackson, LaSalle, Ouachita, Union, Winn | 68 min |
| Apr 29, 2:19 AM CDT | Severe Thunderstorm Warning | SHV | Caldwell, De Soto, Grant, LaSalle, Natchitoches, Sabine and 1 more | 56 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
Shreveport, LA (KSHV), launched 00:00Z, 5.8 hours before the alert went out and 254 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
- 733 J/kg
- Mixed-layer CIN
- -250 J/kg
- Mixed-layer LCL
- 1058 m above ground
- 0-6 km bulk shear
- 43 kt
- 0-1 km storm-relative helicity
- 119 m²/s²
- 0-3 km storm-relative helicity
- 217 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 28, 7:35 PM CDT | Severe Thunderstorm Watch | SPC | Arkansas, Baxter, Boone, Bradley, Calhoun, Clark and 51 more | 7 hr |
| Apr 28, 8:06 PM CDT | Mesoscale Discussion | SPC | Lafayette, Little River, Miller, Sevier | 54 min |
| Apr 28, 8:25 PM CDT | Severe Thunderstorm Watch | SPC | Columbia, Hempstead, Howard, Lafayette, Little River, Miller and 3 more | 9 hr |
| Apr 28, 10:08 PM CDT | Mesoscale Discussion | SPC | Clark, Cleburne, Conway, Craighead, Faulkner, Garland and 15 more | 97 min |
| Apr 28, 11:12 PM CDT | Mesoscale Discussion | SPC | Arkansas, Bradley, Calhoun, Cleveland, Crittenden, Cross and 11 more | 63 min |
| Apr 28, 11:57 PM CDT | Mesoscale Discussion | SPC | Ashley, Chicot | 63 min |
| Apr 29, 1:56 AM CDT | Mesoscale Discussion | SPC | Allen, Avoyelles, Beauregard, Bienville, Caldwell, Catahoula and 19 more | 2 hr |
| Apr 29, 2:40 AM CDT | Severe Thunderstorm Watch | SPC | Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 23 more | 6 hr |
| Apr 29, 5:05 AM CDT | Mesoscale Discussion | SPC | Calcasieu, Cameron | 115 min |
Nearby
Severe Thunderstorm Watches in Louisiana, 2020Severe Thunderstorm Watches in Mississippi, 2020Severe Thunderstorm Watches in Arkansas, 2020Every severe thunderstorm watch in 2020
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.