Alert archive / Louisiana / Severe Thunderstorm Watches in 2007
Severe Thunderstorm Watch 735
The Storm Prediction Center issued this severe thunderstorm watch at Nov 21, 2007, 2:29 PM CST for 6 counties in Arkansas; 23 parishes in Louisiana; 20 counties in Texas. It was in force for 8 hr.
The area
The outline as issued.
The facts
- Issued
- Nov 21, 2007, 2:29 PM CST (20:29 UTC)
- Expired
- Nov 21, 2007, 10:00 PM CST
- In force
- 8 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 49 counties
Ashley County, AR, Chicot County, AR, Columbia County, AR, Lafayette County, AR, Miller County, AR, Union County, AR, Beauregard Parish, LA, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Caldwell Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Union Parish, LA, Vernon Parish, LA, Webster Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Angelina County, TX, Cherokee County, TX, Gregg County, TX, Hardin County, TX, Harrison County, TX, Jasper County, TX, Liberty County, TX, Marion County, TX, Nacogdoches County, TX, Newton County, TX, Panola County, TX, Polk County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Shelby County, TX, Trinity County, TX, Tyler County, TX, Walker County, TX
The radar
The Shreveport radar (KSHV), 48 km from the middle of the area, began a volume at 20:29 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
- 30%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 40%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
27 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Nov 21, 2:38 PM CST | Severe Thunderstorm Warning | SHV | San Augustine | 52 min |
| Nov 21, 3:06 PM CST | Severe Thunderstorm Warning | SHV | Columbia, Lafayette, Nevada | 54 min |
| Nov 21, 3:09 PM CST | Severe Thunderstorm Warning | SHV | Harrison | 66 min |
| Nov 21, 3:14 PM CST | Severe Thunderstorm Warning | SHV | Sabine | 61 min |
| Nov 21, 3:18 PM CST | Severe Thunderstorm Warning | LCH | Jasper, Newton | 27 min |
| Nov 21, 3:25 PM CST | Severe Thunderstorm Warning | SHV | Sabine | 65 min |
| Nov 21, 3:36 PM CST | Severe Thunderstorm Warning | SHV | Lafayette | 24 min |
| Nov 21, 3:39 PM CST | Severe Thunderstorm Warning | SHV | Caddo | 66 min |
| Nov 21, 3:43 PM CST | Severe Thunderstorm Warning | SHV | Panola, Rusk | 53 min |
| Nov 21, 3:53 PM CST | Severe Thunderstorm Warning | SHV | Columbia | 67 min |
| Nov 21, 4:04 PM CST | Severe Thunderstorm Warning | SHV | Natchitoches | 56 min |
| Nov 21, 4:19 PM CST | Severe Thunderstorm Warning | LCH | Vernon | 56 min |
| Nov 21, 4:23 PM CST | Severe Thunderstorm Warning | LCH | Beauregard | 67 min |
| Nov 21, 4:26 PM CST | Severe Thunderstorm Warning | HGX | Liberty | 34 min |
| Nov 21, 4:43 PM CST | Severe Thunderstorm Warning | LCH | Beauregard, Calcasieu | 62 min |
| Nov 21, 4:50 PM CST | Severe Thunderstorm Warning | SHV | Columbia, Union | 55 min |
| Nov 21, 5:10 PM CST | Severe Thunderstorm Warning | SHV | Grant | 65 min |
| Nov 21, 5:17 PM CST | Severe Thunderstorm Warning | LCH | Beauregard, Vernon | 58 min |
| Nov 21, 5:29 PM CST | Severe Thunderstorm Warning | SHV | Union | 31 min |
| Nov 21, 5:46 PM CST | Severe Thunderstorm Warning | LCH | Allen, Beauregard, Calcasieu, Jefferson Davis, Rapides, Vernon | 59 min |
| Nov 21, 6:21 PM CST | Severe Thunderstorm Warning | SHV | Lincoln, Union | 39 min |
| Nov 21, 6:33 PM CST | Severe Thunderstorm Warning | JAN | Morehouse | 57 min |
| Nov 21, 7:06 PM CST | Severe Thunderstorm Warning | LCH | Hardin, Jasper, Tyler | 39 min |
| Nov 21, 7:10 PM CST | Severe Thunderstorm Warning | JAN | Franklin, Richland, West Carroll | 35 min |
| Nov 21, 7:20 PM CST | Severe Thunderstorm Warning | LCH | Hardin, Jasper, Orange | 25 min |
| Nov 21, 7:39 PM CST | Severe Thunderstorm Warning | LCH | Beauregard, Calcasieu, Cameron | 51 min |
| Nov 21, 7:44 PM CST | Severe Thunderstorm Warning | JAN | Chicot | 31 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, 8.5 hours before the alert went out and 47 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
- 642 J/kg
- Mixed-layer CIN
- -45 J/kg
- Mixed-layer LCL
- 615 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- 143 m²/s²
- 0-3 km storm-relative helicity
- 171 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.3
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Nov 21, 11:17 AM CST | Mesoscale Discussion | SPC | Arkansas, Ashley, Baxter, Bradley, Calhoun, Chicot and 58 more | 118 min |
| Nov 21, 12:47 PM CST | Tornado Watch | SPC | Arkansas, Bradley, Calhoun, Clark, Clay, Cleburne and 43 more | 6 hr |
| Nov 21, 3:18 PM CST | Mesoscale Discussion | SPC | Arkansas, Clark, Clay, Cleburne, Cleveland, Conway and 34 more | 87 min |
| Nov 21, 5:10 PM CST | Mesoscale Discussion | SPC | Ashley, Chicot, Columbia, Union | 65 min |
| Nov 21, 12:24 PM CST | Mesoscale Discussion | SPC | Ascension, East Baton Rouge, East Feliciana, Iberville, Lafayette, Livingston and 13 more | 2 hr |
| Nov 21, 1:32 PM CST | Mesoscale Discussion | SPC | Beauregard, Bienville, Bossier, Caddo, Claiborne, De Soto and 9 more | 118 min |
| Nov 21, 5:29 PM CST | Severe Thunderstorm Watch | SPC | Acadia, Allen, Ascension, Avoyelles, Calcasieu, Catahoula and 19 more | 6 hr |
Nearby
Severe Thunderstorm Watches in Louisiana, 2007Severe Thunderstorm Watches in Texas, 2007Severe Thunderstorm Watches in Arkansas, 2007Every severe thunderstorm watch in 2007
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.