Alert archive / Texas / Tornado Watches in 2009
Tornado Watch 806
The Storm Prediction Center issued this tornado watch at Dec 23, 2009, 8:48 PM CST for 7 counties in Arkansas; 13 parishes in Louisiana; 49 counties in Texas. It was in force for 9 hr.
The area
The outline as issued.
The facts
- Issued
- Dec 23, 2009, 8:48 PM CST (02:48 UTC)
- Expired
- Dec 24, 2009, 6:00 AM CST
- In force
- 9 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 69 counties
Columbia County, AR, Hempstead County, AR, Howard County, AR, Lafayette County, AR, Little River County, AR, Miller County, AR, Sevier County, AR, Beauregard Parish, LA, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Natchitoches Parish, LA, Red River Parish, LA, Sabine Parish, LA, Vernon Parish, LA, Webster Parish, LA, Angelina County, TX, Austin County, TX, Bowie County, TX, Brazoria County, TX, Brazos County, TX, Burleson County, TX, Camp County, TX, Cass County, TX, Chambers County, TX, Cherokee County, TX, Colorado County, TX, Fort Bend County, TX, Franklin County, TX, Galveston County, TX, Gregg County, TX, Grimes County, TX, Hardin County, TX, Harris County, TX, Harrison County, TX, Houston County, TX, Jasper County, TX, Jefferson County, TX, Liberty County, TX, Madison County, TX, Marion County, TX, Matagorda County, TX, Montgomery County, TX, Morris County, TX, Nacogdoches County, TX, Newton County, TX, Orange County, TX, Panola County, TX, Polk County, TX, Red River County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Shelby County, TX, Smith County, TX, Titus County, TX, Trinity County, TX, Tyler County, TX, Upshur County, TX, Walker County, TX, Waller County, TX, Washington County, TX, Wharton County, TX, Wood County, TX
The radar
The Shreveport radar (KSHV), 95 km from the middle of the area, began a volume at 02:50 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
- 50%
- One or more EF2 to EF5 tornadoes
- 40%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
39 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 23, 9:18 PM CST | Severe Thunderstorm Warning | SHV | Columbia, Hempstead, Lafayette, Miller, Nevada | 42 min |
| Dec 23, 9:25 PM CST | Tornado Warning | SHV | Miller | 50 min |
| Dec 23, 9:29 PM CST | Flash Flood Warning | SHV | Hempstead, Lafayette, Little River, Miller, Nevada | 3 hr |
| Dec 23, 10:03 PM CST | Tornado Warning | SHV | Hempstead, Lafayette, Miller, Nevada | 42 min |
| Dec 23, 10:06 PM CST | Tornado Warning | SHV | Miller | 39 min |
| Dec 23, 10:13 PM CST | Severe Thunderstorm Warning | SHV | Angelina, Nacogdoches | 47 min |
| Dec 23, 10:26 PM CST | Tornado Warning | SHV | Angelina, Nacogdoches | 49 min |
| Dec 23, 10:40 PM CST | Severe Thunderstorm Warning | SHV | Columbia, Lafayette, Nevada, Union | 27 min |
| Dec 23, 10:47 PM CST | Tornado Warning | SHV | Hempstead, Lafayette, Miller | 43 min |
| Dec 23, 10:52 PM CST | Tornado Warning | SHV | Panola, Shelby | 38 min |
| Dec 23, 11:09 PM CST | Tornado Warning | SHV | Nacogdoches, Panola, Rusk, Shelby | 51 min |
| Dec 23, 11:19 PM CST | Severe Thunderstorm Warning | HGX | Houston, Trinity | 21 min |
| Dec 23, 11:39 PM CST | Tornado Warning | SHV | Panola, Shelby | 51 min |
| Dec 23, 11:51 PM CST | Tornado Warning | SHV | Angelina, Nacogdoches, San Augustine | 39 min |
| Dec 24, 12:15 AM CST | Flash Flood Warning | SHV | Caddo, De Soto, Sabine | 3 hr |
| Dec 24, 12:23 AM CST | Tornado Warning | SHV | Caddo, De Soto | 41 min |
| Dec 24, 12:41 AM CST | Flash Flood Warning | SHV | Little River, Miller | 4 hr |
| Dec 24, 1:23 AM CST | Tornado Warning | LCH | Jasper, Tyler | 37 min |
| Dec 24, 1:51 AM CST | Severe Thunderstorm Warning | SHV | De Soto, Sabine | 39 min |
| Dec 24, 2:08 AM CST | Tornado Warning | SHV | Sabine | 37 min |
| Dec 24, 2:35 AM CST | Flash Flood Warning | SHV | Bienville, Bossier, Caddo, De Soto, Natchitoches, Red River and 2 more | 3 hr |
| Dec 24, 2:41 AM CST | Tornado Warning | SHV | Sabine | 49 min |
| Dec 24, 2:48 AM CST | Tornado Warning | SHV | Bossier, Webster | 27 min |
| Dec 24, 2:54 AM CST | Severe Thunderstorm Warning | SHV | De Soto, Natchitoches, Red River, Sabine | 51 min |
| Dec 24, 2:54 AM CST | Tornado Warning | LCH | Jasper, Newton | 36 min |
| Dec 24, 3:03 AM CST | Tornado Warning | SHV | Bienville, De Soto, Natchitoches, Red River, Webster | 42 min |
| Dec 24, 3:18 AM CST | Tornado Warning | SHV | Sabine | 42 min |
| Dec 24, 3:23 AM CST | Tornado Warning | SHV | De Soto, Natchitoches, Red River, Sabine | 37 min |
| Dec 24, 3:37 AM CST | Flash Flood Warning | SHV | Columbia, Union | 4 hr |
| Dec 24, 4:17 AM CST | Tornado Warning | SHV | De Soto, Natchitoches, Sabine | 43 min |
| Dec 24, 4:21 AM CST | Tornado Warning | SHV | Bienville, Claiborne, Lincoln, Webster | 39 min |
| Dec 24, 4:28 AM CST | Severe Thunderstorm Warning | SHV | Bienville, Jackson, Natchitoches, Red River, Winn | 47 min |
| Dec 24, 4:54 AM CST | Severe Thunderstorm Warning | SHV | Bienville, Claiborne, Lincoln, Union | 51 min |
| Dec 24, 4:59 AM CST | Severe Thunderstorm Warning | SHV | De Soto, Sabine | 46 min |
| Dec 24, 5:21 AM CST | Severe Thunderstorm Warning | SHV | Bienville, Natchitoches, Red River | 39 min |
| Dec 24, 5:24 AM CST | Tornado Warning | SHV | Bienville, Natchitoches, Red River | 51 min |
| Dec 24, 5:32 AM CST | Flash Flood Warning | SHV | Columbia, Union | 4 hr |
| Dec 24, 5:40 AM CST | Tornado Warning | SHV | Bienville, Lincoln | 50 min |
| Dec 24, 5:54 AM CST | Flash Flood Warning | SHV | Bienville, De Soto, Natchitoches, Red River, Sabine | 4 hr |
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, 2.8 hours before the alert went out and 104 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
- 649 J/kg
- Mixed-layer CIN
- -5 J/kg
- Mixed-layer LCL
- 446 m above ground
- 0-6 km bulk shear
- 42 kt
- 0-1 km storm-relative helicity
- 329 m²/s²
- 0-3 km storm-relative helicity
- 329 m²/s²
- Significant tornado parameter
- 1.0
- Supercell composite
- 5.8
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 23, 7:50 PM CST | Mesoscale Discussion | SPC | Clark, Columbia, Hempstead, Howard, Lafayette, Little River and 7 more | 85 min |
| Dec 23, 11:06 PM CST | Mesoscale Discussion | SPC | Clark, Columbia, Dallas, Hempstead, Hot Spring, Howard and 7 more | 114 min |
| Dec 24, 3:30 AM CST | Mesoscale Discussion | SPC | Ashley, Bradley, Calhoun, Chicot, Columbia, Lafayette and 2 more | 2 hr |
| Dec 24, 4:50 AM CST | Tornado Watch | SPC | Ashley, Chicot, Union | 7 hr |
| Dec 24, 7:30 AM CST | Mesoscale Discussion | SPC | Ashley | 90 min |
| Dec 24, 10:13 AM CST | Mesoscale Discussion | SPC | Ashley, Chicot, Union | 62 min |
| Dec 24, 9:34 AM CST | Mesoscale Discussion | SPC | Ascension, Assumption, East Baton Rouge, East Feliciana, Iberville, Jefferson and 16 more | 56 min |
| Dec 24, 10:37 AM CST | Tornado Watch | SPC | Jefferson, Orleans, Plaquemines, Saint Bernard, Saint Charles, Saint Tammany and 2 more | 7 hr |
| Dec 24, 1:14 PM CST | Mesoscale Discussion | SPC | Jefferson, Orleans, Plaquemines, Saint Bernard, Saint Tammany, Washington | 61 min |
| Dec 23, 11:43 PM CST | Mesoscale Discussion | SPC | Archer, Baylor, Childress, Cottle, Dickens, Foard and 9 more | 6 hr |
| Dec 24, 7:25 AM CST | Mesoscale Discussion | SPC | Archer, Baylor, Callahan, Childress, Clay, Collingsworth and 23 more | 6 hr |
| Dec 24, 11:23 AM CST | Mesoscale Discussion | SPC | Collin, Delta, Denton, Fannin, Grayson, Hopkins and 3 more | 6 hr |
Nearby
Tornado Watches in Texas, 2009Tornado Watches in Louisiana, 2009Tornado Watches in Arkansas, 2009Every tornado watch in 2009
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.