Alert archive / Louisiana / Severe Thunderstorm Watches in 2003
Severe Thunderstorm Watch 879
The Storm Prediction Center issued this severe thunderstorm watch at Aug 21, 2003, 3:10 PM CDT for 5 counties in Arkansas; 18 parishes in Louisiana; 18 counties in Texas. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 21, 2003, 3:10 PM CDT (20:10 UTC)
- Expired
- Aug 21, 2003, 8:00 PM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
All 41 counties
Ashley County, AR, Columbia County, AR, Lafayette County, AR, Miller County, AR, Union County, AR, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Caldwell Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Grant Parish, LA, Jackson Parish, LA, Lincoln Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Rapides Parish, LA, Red River Parish, LA, Sabine Parish, LA, Union Parish, LA, Vernon Parish, LA, Webster Parish, LA, Winn Parish, LA, Angelina County, TX, Camp County, TX, Cass County, TX, Cherokee County, TX, Gregg County, TX, Harrison County, TX, Houston County, TX, Marion County, TX, Morris County, TX, Nacogdoches County, TX, Panola County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX, Titus County, TX, Trinity County, TX, Upshur County, TX
The radar
The Shreveport radar (KSHV), 60 km from the middle of the area, began a volume at 20:12 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.
Warnings issued inside it
10 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 21, 5:05 PM CDT | Severe Thunderstorm Warning | SHV | De Soto, Sabine | 55 min |
| Aug 21, 5:24 PM CDT | Severe Thunderstorm Warning | SHV | Red River | 66 min |
| Aug 21, 5:58 PM CDT | Severe Thunderstorm Warning | SHV | Webster | 62 min |
| Aug 21, 6:03 PM CDT | Severe Thunderstorm Warning | SHV | Caddo | 42 min |
| Aug 21, 6:33 PM CDT | Severe Thunderstorm Warning | SHV | Panola | 42 min |
| Aug 21, 6:33 PM CDT | Severe Thunderstorm Warning | SHV | Nacogdoches | 57 min |
| Aug 21, 6:59 PM CDT | Severe Thunderstorm Warning | HGX | Trinity | 46 min |
| Aug 21, 7:06 PM CDT | Severe Thunderstorm Warning | SHV | Columbia | 54 min |
| Aug 21, 7:46 PM CDT | Severe Thunderstorm Warning | SHV | Webster | 59 min |
| Aug 21, 7:50 PM CDT | Severe Thunderstorm Warning | SHV | Cherokee, Smith | 55 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 12:00Z, 8.2 hours before the alert went out and 67 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
- 1653 J/kg
- Mixed-layer CIN
- -79 J/kg
- Mixed-layer LCL
- 1095 m above ground
- 0-6 km bulk shear
- 18 kt
- 0-1 km storm-relative helicity
- -22 m²/s²
- 0-3 km storm-relative helicity
- -6 m²/s²
- Significant tornado parameter
- -0.1
- Supercell composite
- -0.2
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 21, 12:39 PM CDT | Mesoscale Discussion | SPC | Ashley, Bradley, Calhoun, Chicot, Cleveland, Desha and 3 more | 3 hr |
| Aug 21, 5:54 PM CDT | Mesoscale Discussion | SPC | Columbia, Lafayette, Miller, Union | 66 min |
Nearby
Severe Thunderstorm Watches in Louisiana, 2003Severe Thunderstorm Watches in Texas, 2003Severe Thunderstorm Watches in Arkansas, 2003Every severe thunderstorm watch in 2003
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.