Alert archive / Texas / Tornado Watches in 2009

Tornado Watch 198

April 27, 200939 counties in Texas

The Storm Prediction Center issued this tornado watch at Apr 27, 2009, 6:08 AM CDT for 39 counties in Texas. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Apr 27, 2009, 6:08 AM CDT (11:08 UTC)
Expired
Apr 27, 2009, 1:00 PM CDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
60 kt
All 39 counties

Anderson County, TX, Bastrop County, TX, Bell County, TX, Blanco County, TX, Bosque County, TX, Brazos County, TX, Burleson County, TX, Burnet County, TX, Caldwell County, TX, Coryell County, TX, Ellis County, TX, Falls County, TX, Freestone County, TX, Gillespie County, TX, Grimes County, TX, Hamilton County, TX, Hays County, TX, Henderson County, TX, Hill County, TX, Houston County, TX, Johnson County, TX, Kaufman County, TX, Lampasas County, TX, Lee County, TX, Leon County, TX, Limestone County, TX, Llano County, TX, Madison County, TX, McLennan County, TX, Milam County, TX, Mills County, TX, Navarro County, TX, Robertson County, TX, Somervell County, TX, Travis County, TX, Van Zandt County, TX, Walker County, TX, Washington County, TX, Williamson County, TX

The radar

The Dallas/Ft Worth radar (KFWS), 105 km from the middle of the area, began a volume at 11:10 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
30%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
50%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
10%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 27, 6:21 AM CDTSevere Thunderstorm WarningFWDBosque54 min
Apr 27, 6:30 AM CDTSevere Thunderstorm WarningFWDEllis60 min
Apr 27, 6:45 AM CDTSevere Thunderstorm WarningFWDCoryell, Lampasas75 min
Apr 27, 6:58 AM CDTSevere Thunderstorm WarningFWDBosque, Hill62 min
Apr 27, 6:59 AM CDTTornado WarningFWDLampasas46 min
Apr 27, 7:21 AM CDTFlash Flood WarningFWDCoryell, Hamilton, Lampasas, Mills114 min
Apr 27, 7:43 AM CDTSevere Thunderstorm WarningFWDMcLennan62 min
Apr 27, 7:57 AM CDTSevere Thunderstorm WarningFWDLimestone, Navarro78 min
Apr 27, 7:59 AM CDTSevere Thunderstorm WarningFWDHill33 min
Apr 27, 8:38 AM CDTTornado WarningFWDHenderson, Navarro52 min
Apr 27, 8:50 AM CDTSevere Thunderstorm WarningFWDKaufman, Van Zandt55 min
Apr 27, 9:10 AM CDTTornado WarningFWDKaufman, Van Zandt50 min
Apr 27, 9:42 AM CDTFlash Flood WarningFWDBosque, Coryell, Hamilton, Lampasas, Mills108 min
Apr 27, 9:47 AM CDTSevere Thunderstorm WarningFWDVan Zandt39 min
Apr 27, 11:32 AM CDTFlash Flood WarningFWDBosque, Coryell, Hamilton, Lampasas, McLennan, Mills3 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

Fort Worth, TX (KFWD), launched 00:00Z, 11.1 hours before the alert went out and 133 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, Fort Worth, TX at 00:00Z on 2009-04-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 479 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, Fort Worth, TX at 00:00Z on 2009-04-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 228 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
479 J/kg
Mixed-layer CIN
-125 J/kg
Mixed-layer LCL
1254 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
228 m²/s²
0-3 km storm-relative helicity
360 m²/s²
Significant tornado parameter
0.3
Supercell composite
3.3

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 26, 8:04 PM CDTTornado WatchSPCBlanco, Brown, Burnet, Callahan, Coke, Coleman and 30 more7 hr
Apr 26, 8:42 PM CDTMesoscale DiscussionSPCArcher, Baylor, Childress, Clay, Collingsworth, Cottle and 14 more2 hr
Apr 26, 10:46 PM CDTMesoscale DiscussionSPCBlanco, Brown, Callahan, Coke, Coleman, Concho and 22 more119 min
Apr 27, 1:49 AM CDTMesoscale DiscussionSPCBrown, Callahan, Coke, Coleman, Concho, Crockett and 24 more86 min
Apr 27, 2:44 AM CDTSevere Thunderstorm WatchSPCBrown, Callahan, Coke, Coleman, Concho, Crockett and 23 more7 hr
Apr 27, 5:36 AM CDTMesoscale DiscussionSPCBosque, Brown, Coke, Comanche, Concho, Coryell and 17 more84 min
Apr 27, 7:43 AM CDTMesoscale DiscussionSPCCoke, Concho, Crockett, Irion, Kimble, McCulloch and 8 more92 min
Apr 27, 7:55 AM CDTSevere Thunderstorm WatchSPCBandera, Bexar, Comal, Edwards, Frio, Guadalupe and 9 more5 hr
Apr 27, 8:59 AM CDTMesoscale DiscussionSPCAnderson, Angelina, Bell, Brazos, Burleson, Burnet and 38 more91 min
Apr 27, 9:28 AM CDTSevere Thunderstorm WatchSPCBowie, Camp, Cass, Cherokee, Franklin, Gregg and 12 more12 hr
Apr 27, 11:42 AM CDTMesoscale DiscussionSPCAnderson, Bastrop, Bell, Blanco, Brazos, Burleson and 19 more63 min
Apr 27, 12:00 PM CDTMesoscale DiscussionSPCAtascosa, Bandera, Bexar, Comal, Edwards, Kendall and 6 more60 min
Apr 27, 1:14 PM CDTMesoscale DiscussionSPCBowie, Camp, Cass, Gregg, Harrison, Marion and 8 more91 min
Apr 27, 2:24 PM CDTMesoscale DiscussionSPCAngelina, Bowie, Cass, Cherokee, Gregg, Harrison and 10 more66 min
Apr 27, 2:57 PM CDTSevere Thunderstorm WatchSPCBowie, Cass, Harrison, Marion, Panola, Shelby6 hr
Apr 27, 3:50 PM CDTMesoscale DiscussionSPCAransas, Austin, Bee, Brazoria, Calhoun, Chambers and 20 more85 min
Apr 27, 3:58 PM CDTTornado WatchSPCBrazoria, Calhoun, Chambers, Colorado, DeWitt, Fort Bend and 10 more5 hr
Apr 27, 5:59 PM CDTMesoscale DiscussionSPCBorden, Dawson, Fisher, Garza, Kent, Lynn and 4 more2 hr
Apr 27, 6:30 PM CDTMesoscale DiscussionSPCAransas, Brazoria, Calhoun, Chambers, Galveston, Hardin and 4 more2 hr

Nearby

Tornado Watches in Texas, 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.