Alert archive / Texas / Tornado Watches in 2009

Tornado Watch 805

December 23, 20094 states

The Storm Prediction Center issued this tornado watch at Dec 23, 2009, 1:59 PM CST for 4 states. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Dec 23, 2009, 1:59 PM CST (19:59 UTC)
Expired
Dec 23, 2009, 9:00 PM CST
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt
All 69 counties

Miller County, AR, Beauregard Parish, LA, Bossier Parish, LA, Caddo Parish, LA, De Soto Parish, LA, Natchitoches Parish, LA, Red River Parish, LA, Sabine Parish, LA, Vernon Parish, LA, Atoka County, OK, Bryan County, OK, Choctaw County, OK, Latimer County, OK, McCurtain County, OK, Pittsburg County, OK, Pushmataha County, OK, Anderson County, TX, Angelina County, TX, Austin County, TX, Bowie County, TX, Brazos County, TX, Burleson County, TX, Camp County, TX, Cass County, TX, Cherokee County, TX, Delta County, TX, Fannin County, TX, Franklin County, TX, Freestone County, TX, Gregg County, TX, Grimes County, TX, Harrison County, TX, Henderson County, TX, Hopkins County, TX, Houston County, TX, Hunt County, TX, Jasper County, TX, Kaufman County, TX, Lamar County, TX, Leon County, TX, Limestone County, TX, Madison County, TX, Marion County, TX, Montgomery County, TX, Morris County, TX, Nacogdoches County, TX, Navarro County, TX, Newton County, TX, Panola County, TX, Polk County, TX, Rains County, TX, Red River County, TX, Robertson County, TX, Rockwall 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, Van Zandt County, TX, Walker County, TX, Waller County, TX, Washington County, TX, Wood County, TX

The radar

The Shreveport radar (KSHV), 124 km from the middle of the area, began a volume at 19:59 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
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
10%
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
90%

Warnings issued inside it

19 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Dec 23, 2:31 PM CSTSevere Thunderstorm WarningTSAPittsburg33 min
Dec 23, 2:42 PM CSTTornado WarningSHVCherokee, Rusk, Smith48 min
Dec 23, 3:39 PM CSTSevere Thunderstorm WarningSHVRed River40 min
Dec 23, 4:24 PM CSTTornado WarningSHVGregg, Harrison51 min
Dec 23, 5:10 PM CSTTornado WarningSHVHarrison, Marion35 min
Dec 23, 5:13 PM CSTTornado WarningHGXHouston, Trinity, Walker47 min
Dec 23, 5:15 PM CSTTornado WarningSHVRusk30 min
Dec 23, 5:49 PM CSTTornado WarningSHVCass, Marion26 min
Dec 23, 6:01 PM CSTSevere Thunderstorm WarningHGXHouston44 min
Dec 23, 6:12 PM CSTTornado WarningSHVCass33 min
Dec 23, 6:36 PM CSTSevere Thunderstorm WarningSHVCherokee, Nacogdoches, Rusk24 min
Dec 23, 6:40 PM CSTTornado WarningSHVBowie, Cass50 min
Dec 23, 6:58 PM CSTTornado WarningSHVCass, Marion32 min
Dec 23, 7:12 PM CSTTornado WarningSHVRusk48 min
Dec 23, 7:25 PM CSTTornado WarningSHVMiller35 min
Dec 23, 7:28 PM CSTFlash Flood WarningSHVMiller4 hr
Dec 23, 7:45 PM CSTTornado WarningSHVRusk35 min
Dec 23, 8:31 PM CSTSevere Thunderstorm WarningSHVLafayette, Miller44 min
Dec 23, 8:45 PM CSTTornado WarningSHVHarrison, Marion45 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, 8.0 hours before the alert went out and 132 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.

Skew-T log-pSkew-T log-p diagram, Shreveport, LA at 12:00Z on 2009-12-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 12 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Shreveport, LA at 12:00Z on 2009-12-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 377 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
12 J/kg
Mixed-layer CIN
-129 J/kg
Mixed-layer LCL
489 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
377 m²/s²
0-3 km storm-relative helicity
435 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 23, 2:37 AM CSTMesoscale DiscussionSPCCrawford, Howard, Little River, Miller, Polk, Scott and 2 more2 hr
Dec 23, 10:31 AM CSTMesoscale DiscussionSPCBenton89 min
Dec 23, 5:21 PM CSTMesoscale DiscussionSPCLafayette, Miller114 min
Dec 23, 12:18 PM CSTMesoscale DiscussionSPCAtoka, Bryan, Carter, Choctaw, Coal, Creek and 17 more57 min
Dec 23, 1:03 PM CSTMesoscale DiscussionSPCChoctaw57 min
Dec 23, 3:00 PM CSTMesoscale DiscussionSPCBosque, Comanche, Cooke, Dallas, Denton, Erath and 8 more60 min

Nearby

Tornado Watches in Texas, 2009Tornado Watches in Louisiana, 2009Tornado Watches in Oklahoma, 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.