Alert archive / Texas / Mesoscale Discussions in 2009

Mesoscale Discussion 497

April 17, 200969 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 17, 2009, 9:56 AM CDT for 69 counties in Texas. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued
Apr 17, 2009, 9:56 AM CDT (14:56 UTC)
Expired
Apr 17, 2009, 11:30 AM CDT
In force
94 min
Issued by
the Storm Prediction Center
All 69 counties

Anderson County, TX, Angelina County, TX, Atascosa County, TX, Austin County, TX, Bastrop County, TX, Bee County, TX, Bell County, TX, Bexar County, TX, Brazoria County, TX, Brazos County, TX, Burleson County, TX, Caldwell County, TX, Calhoun County, TX, Chambers County, TX, Colorado County, TX, Comal County, TX, DeWitt County, TX, Dimmit County, TX, Falls County, TX, Fayette County, TX, Fort Bend County, TX, Freestone County, TX, Frio County, TX, Galveston County, TX, Goliad County, TX, Gonzales County, TX, Grimes County, TX, Guadalupe County, TX, Hardin County, TX, Harris County, TX, Hays County, TX, Houston County, TX, Jackson County, TX, Jasper County, TX, Jefferson County, TX, Karnes County, TX, La Salle County, TX, Lavaca County, TX, Lee County, TX, Leon County, TX, Liberty County, TX, Limestone County, TX, Live Oak County, TX, Madison County, TX, Matagorda County, TX, Maverick County, TX, McLennan County, TX, McMullen County, TX, Medina County, TX, Milam County, TX, Montgomery County, TX, Newton County, TX, Orange County, TX, Polk County, TX, Refugio County, TX, Robertson County, TX, San Jacinto County, TX, Travis County, TX, Trinity County, TX, Tyler County, TX, Uvalde County, TX, Victoria County, TX, Walker County, TX, Waller County, TX, Washington County, TX, Wharton County, TX, Williamson County, TX, Wilson County, TX, Zavala County, TX

The radar

The Houston radar (KHGX), 141 km from the middle of the area, began a volume at 14:55 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.

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Corpus Christi, TX (KCRP), launched 12:00Z, 2.9 hours before the alert went out and 229 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, Corpus Christi, TX at 12:00Z on 2009-04-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2605 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, Corpus Christi, TX at 12:00Z on 2009-04-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 79 square meters per square second.193958Sfc1 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
2605 J/kg
Mixed-layer CIN
-15 J/kg
Mixed-layer LCL
468 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
79 m²/s²
0-3 km storm-relative helicity
186 m²/s²
Significant tornado parameter
1.4
Supercell composite
7.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 16, 7:31 PM CDTMesoscale DiscussionSPCBrewster, Kinney, Pecos, Terrell, Val Verde89 min
Apr 16, 7:43 PM CDTMesoscale DiscussionSPCAnderson, Angelina, Cherokee, Dallas, Ellis, Freestone and 23 more62 min
Apr 16, 8:36 PM CDTMesoscale DiscussionSPCAndrews, Borden, Briscoe, Castro, Childress, Coke and 34 more84 min
Apr 16, 9:20 PM CDTMesoscale DiscussionSPCArmstrong, Carson, Collingsworth, Dallam, Deaf Smith, Donley and 14 more55 min
Apr 16, 10:56 PM CDTMesoscale DiscussionSPCCoke, Concho, Crockett, Fisher, Irion, Jones and 11 more94 min
Apr 16, 11:35 PM CDTSevere Thunderstorm WatchSPCBandera, Brown, Callahan, Coleman, Comanche, Concho and 26 more6 hr
Apr 17, 2:32 AM CDTMesoscale DiscussionSPCBrown, Callahan, Coleman, Comanche, Concho, Eastland and 20 more118 min
Apr 17, 5:16 AM CDTMesoscale DiscussionSPCBlanco, Burnet, Edwards, Gillespie, Kendall, Kerr and 8 more59 min
Apr 17, 7:28 AM CDTMesoscale DiscussionSPCAtascosa, Bandera, Bastrop, Bell, Bexar, Blanco and 23 more92 min
Apr 17, 7:48 AM CDTSevere Thunderstorm WatchSPCAtascosa, Bandera, Bastrop, Bell, Bexar, Blanco and 35 more5 hr
Apr 17, 10:24 AM CDTTornado WatchSPCAustin, Brazoria, Brazos, Burleson, Chambers, Colorado and 17 more7 hr
Apr 17, 12:10 PM CDTMesoscale DiscussionSPCAnderson, Angelina, Austin, Brazos, Cherokee, Colorado and 19 more3 hr
Apr 17, 12:38 PM CDTMesoscale DiscussionSPCAtascosa, Bee, DeWitt, Goliad, Gonzales, Karnes and 7 more37 min
Apr 17, 12:51 PM CDTSevere Thunderstorm WatchSPCAtascosa, Bee, Calhoun, DeWitt, Fayette, Frio and 10 more5 hr
Apr 17, 1:45 PM CDTMesoscale DiscussionSPCBrazoria, Chambers, Colorado, Fort Bend, Galveston, Hardin and 11 more2 hr
Apr 17, 3:19 PM CDTMesoscale DiscussionSPCAransas, Atascosa, Bastrop, Bee, Bell, Bexar and 31 more56 min
Apr 17, 3:24 PM CDTMesoscale DiscussionSPCChildress, Collingsworth, Cottle, Foard, Gray, Hansford and 13 more96 min
Apr 17, 3:44 PM CDTTornado WatchSPCAransas, Austin, Bee, Brazoria, Calhoun, Chambers and 22 more6 hr
Apr 17, 5:00 PM CDTSevere Thunderstorm WatchSPCBaylor, Childress, Collingsworth, Cottle, Foard, Hardeman and 13 more5 hr
Apr 17, 6:50 PM CDTMesoscale DiscussionSPCAransas, Bee, Brazoria, Calhoun, Chambers, Colorado and 18 more85 min

Nearby

Mesoscale Discussions in Texas, 2009Every mesoscale discussion 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.