Alert archive / Texas / Severe Thunderstorm Watches in 2012
Severe Thunderstorm Watch 687
The Storm Prediction Center issued this severe thunderstorm watch at Dec 19, 2012, 9:56 PM CST for Bossier Parish, Caddo Parish, De Soto Parish, Louisiana; 26 counties in Texas. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Dec 19, 2012, 9:56 PM CST (03:56 UTC)
- Expired
- Dec 20, 2012, 3:00 AM CST
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 60 kt
All 29 counties
Bossier Parish, LA, Caddo Parish, LA, De Soto Parish, LA, Anderson County, TX, Camp County, TX, Cass County, TX, Cherokee County, TX, Delta County, TX, Franklin County, TX, Freestone County, TX, Gregg County, TX, Harrison County, TX, Henderson County, TX, Hopkins County, TX, Hunt County, TX, Kaufman County, TX, Marion County, TX, Morris County, TX, Nacogdoches County, TX, Navarro County, TX, Panola County, TX, Rains County, TX, Rusk County, TX, Shelby County, TX, Smith County, TX, Titus County, TX, Upshur County, TX, Van Zandt County, TX, Wood County, TX
The radar
The Shreveport radar (KSHV), 135 km from the middle of the area, began a volume at 03:59 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
- 5%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 10%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
11 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 19, 10:06 PM CST | Severe Thunderstorm Warning | FWD | Henderson, Kaufman, Navarro, Van Zandt | 54 min |
| Dec 19, 10:07 PM CST | Severe Thunderstorm Warning | FWD | Rains, Van Zandt | 43 min |
| Dec 19, 10:29 PM CST | Severe Thunderstorm Warning | SHV | Camp, Franklin, Morris, Smith, Titus, Upshur and 1 more | 61 min |
| Dec 19, 11:05 PM CST | Severe Thunderstorm Warning | FWD | Henderson | 40 min |
| Dec 19, 11:12 PM CST | Severe Thunderstorm Warning | FWD | Anderson, Freestone | 63 min |
| Dec 19, 11:29 PM CST | Severe Thunderstorm Warning | SHV | Bowie, Cass, Gregg, Harrison, Marion, Morris and 3 more | 61 min |
| Dec 19, 11:32 PM CST | Severe Thunderstorm Warning | SHV | Cherokee, Nacogdoches, Panola, Rusk, Smith | 58 min |
| Dec 20, 12:22 AM CST | Severe Thunderstorm Warning | SHV | Bienville, Bossier, Caddo, Claiborne, De Soto, Webster | 53 min |
| Dec 20, 12:29 AM CST | Severe Thunderstorm Warning | SHV | De Soto | 61 min |
| Dec 20, 1:12 AM CST | Severe Thunderstorm Warning | SHV | Bienville, Bossier, Caddo, Claiborne, De Soto, Lincoln and 2 more | 63 min |
| Dec 20, 1:51 AM CST | Severe Thunderstorm Warning | SHV | Bienville, De Soto, Grant, Jackson, Natchitoches, Red River and 2 more | 54 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, 3.9 hours before the alert went out and 143 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
- 237 J/kg
- Mixed-layer CIN
- -56 J/kg
- Mixed-layer LCL
- 943 m above ground
- 0-6 km bulk shear
- 55 kt
- 0-1 km storm-relative helicity
- 385 m²/s²
- 0-3 km storm-relative helicity
- 445 m²/s²
- Significant tornado parameter
- 0.3
- Supercell composite
- 1.5
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 19, 7:07 PM CST | Mesoscale Discussion | SPC | Baxter, Benton, Boone, Carroll, Conway, Crawford and 24 more | 53 min |
| Dec 19, 7:36 PM CST | Tornado Watch | SPC | Baxter, Benton, Boone, Carroll, Clark, Cleburne and 36 more | 6 hr |
| Dec 19, 10:22 PM CST | Mesoscale Discussion | SPC | Baxter, Boone, Carroll, Clark, Cleburne, Conway and 29 more | 83 min |
| Dec 19, 11:55 PM CST | Mesoscale Discussion | SPC | Ashley, Chicot | 95 min |
| Dec 20, 12:50 AM CST | Mesoscale Discussion | SPC | Arkansas, Ashley, Bradley, Calhoun, Chicot, Cleveland and 23 more | 55 min |
| Dec 20, 1:07 AM CST | Severe Thunderstorm Watch | SPC | Arkansas, Ashley, Bradley, Calhoun, Chicot, Cleveland and 18 more | 5 hr |
| Dec 20, 4:08 AM CST | Mesoscale Discussion | SPC | Chicot, Crittenden | 67 min |
| Dec 20, 4:23 AM CST | Tornado Watch | SPC | Ascension, Assumption, East Baton Rouge, East Feliciana, Iberville, Livingston and 9 more | 9 hr |
| Dec 20, 7:09 AM CST | Mesoscale Discussion | SPC | Saint James, Saint John the Baptist, Saint Tammany, Tangipahoa, Washington | 96 min |
| Dec 20, 9:56 AM CST | Mesoscale Discussion | SPC | Ascension, East Baton Rouge, East Feliciana, Iberville, Livingston, Saint Helena and 6 more | 64 min |
| Dec 19, 9:00 PM CST | Mesoscale Discussion | SPC | Anderson, Camp, Cherokee, Dallas, Ellis, Falls and 19 more | 2 hr |
Nearby
Severe Thunderstorm Watches in Texas, 2012Severe Thunderstorm Watches in Louisiana, 2012Every severe thunderstorm watch in 2012
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.