Alert archive / Texas / Severe Thunderstorm Watches in 2018

Severe Thunderstorm Watch 11

March 18, 201874 counties in Texas

The Storm Prediction Center issued this severe thunderstorm watch at Mar 18, 2018, 4:06 PM CDT for 74 counties in Texas. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Mar 18, 2018, 4:06 PM CDT (21:06 UTC)
Expired: Mar 18, 2018, 9:57 PM CDT
In force: 6 hr
Issued by: the Storm Prediction Center
Largest hail expected: 3 in
Strongest gust expected: 60 kt

All 74 counties

Anderson County, TX, Angelina County, TX, Austin County, TX, Bastrop County, TX, Bell County, TX, Bosque County, TX, Brazos County, TX, Burleson County, TX, Caldwell County, TX, Cherokee County, TX, Collin County, TX, Colorado County, TX, Coryell County, TX, Dallas County, TX, Denton County, TX, Ellis County, TX, Erath County, TX, Falls County, TX, Fayette County, TX, Freestone County, TX, Gonzales County, TX, Gregg County, TX, Grimes County, TX, Guadalupe County, TX, Hamilton County, TX, Harrison County, TX, Henderson County, TX, Hill County, TX, Hood County, TX, Houston County, TX, Hunt County, TX, Jack County, TX, Jackson County, TX, Jasper County, TX, Johnson County, TX, Kaufman County, TX, Lavaca County, TX, Lee County, TX, Leon County, TX, Limestone County, TX, Madison County, TX, McLennan County, TX, Milam County, TX, Montgomery County, TX, Nacogdoches County, TX, Navarro County, TX, Newton County, TX, Palo Pinto County, TX, Panola County, TX, Parker County, TX, Polk County, TX, Rains 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, Somervell County, TX, Tarrant County, TX, Trinity County, TX, Tyler County, TX, Upshur County, TX, Van Zandt County, TX, Walker County, TX, Waller County, TX, Washington County, TX, Wharton County, TX, Williamson County, TX, Wilson County, TX, Wise County, TX, Wood County, TX

The radar

The Dallas/Ft Worth radar (KFWS), 119 km from the middle of the area, began a volume at 21:06 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: 20%
One or more gusts of 65 knots or more: 10%
Ten or more severe hail reports: 40%
One or more hailstones of 2 inches or more: 40%
Six or more combined severe hail and wind reports: 80%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Mar 18, 4:39 PM CDT	Severe Thunderstorm Warning	FWD	Bosque	51 min
Mar 18, 4:42 PM CDT	Severe Thunderstorm Warning	EWX	Lee	18 min
Mar 18, 4:44 PM CDT	Severe Thunderstorm Warning	HGX	Brazos, Burleson	46 min
Mar 18, 4:54 PM CDT	Severe Thunderstorm Warning	FWD	Robertson	36 min
Mar 18, 5:03 PM CDT	Severe Thunderstorm Warning	HGX	Brazos, Grimes, Madison	42 min
Mar 18, 5:14 PM CDT	Severe Thunderstorm Warning	FWD	Hill, Johnson	61 min
Mar 18, 5:23 PM CDT	Severe Thunderstorm Warning	FWD	Bosque, Hill, McLennan	67 min
Mar 18, 5:27 PM CDT	Tornado Warning	FWD	Bosque, Hill	33 min
Mar 18, 5:29 PM CDT	Severe Thunderstorm Warning	HGX	Brazos, Burleson, Grimes, Washington	31 min
Mar 18, 5:36 PM CDT	Severe Thunderstorm Warning	EWX	Lee	39 min
Mar 18, 5:39 PM CDT	Severe Thunderstorm Warning	FWD	Milam, Robertson	66 min
Mar 18, 5:46 PM CDT	Severe Thunderstorm Warning	HGX	Brazos, Grimes, Houston, Madison, Walker	44 min
Mar 18, 5:49 PM CDT	Severe Thunderstorm Warning	HGX	Burleson	26 min
Mar 18, 6:01 PM CDT	Severe Thunderstorm Warning	HGX	Brazos, Burleson, Grimes	29 min
Mar 18, 6:15 PM CDT	Severe Thunderstorm Warning	EWX	Bastrop, Caldwell, Fayette, Gonzales	45 min
Mar 18, 6:18 PM CDT	Severe Thunderstorm Warning	EWX	Fayette, Gonzales, Lavaca	42 min
Mar 18, 6:24 PM CDT	Severe Thunderstorm Warning	FWD	Hill, Limestone, McLennan, Navarro	66 min
Mar 18, 6:29 PM CDT	Severe Thunderstorm Warning	HGX	Houston, Madison, Polk, San Jacinto, Trinity, Walker	46 min
Mar 18, 6:33 PM CDT	Severe Thunderstorm Warning	HGX	Brazos, Burleson, Grimes, Washington	42 min
Mar 18, 6:53 PM CDT	Severe Thunderstorm Warning	EWX	Bastrop, Fayette, Lee	52 min
Mar 18, 7:03 PM CDT	Severe Thunderstorm Warning	HGX	Polk, San Jacinto, Trinity	57 min
Mar 18, 7:14 PM CDT	Severe Thunderstorm Warning	HGX	Brazos, Grimes, Montgomery, Waller, Washington	46 min
Mar 18, 7:28 PM CDT	Severe Thunderstorm Warning	LCH	Jasper, Tyler	47 min
Mar 18, 7:35 PM CDT	Severe Thunderstorm Warning	HGX	Burleson, Washington	40 min
Mar 18, 8:01 PM CDT	Severe Thunderstorm Warning	SHV	Nacogdoches, San Augustine, Shelby	59 min
Mar 18, 8:02 PM CDT	Severe Thunderstorm Warning	HGX	Brazos, Burleson, Grimes	43 min
Mar 18, 8:08 PM CDT	Severe Thunderstorm Warning	HGX	Liberty, Montgomery, San Jacinto	8 min
Mar 18, 8:14 PM CDT	Severe Thunderstorm Warning	HGX	Polk	46 min
Mar 18, 8:16 PM CDT	Severe Thunderstorm Warning	LCH	Jasper, Tyler	44 min
Mar 18, 8:28 PM CDT	Tornado Warning	SHV	San Augustine, Shelby	18 min
Mar 18, 8:31 PM CDT	Severe Thunderstorm Warning	HGX	Montgomery, Polk, San Jacinto, Walker	26 min
Mar 18, 8:36 PM CDT	Severe Thunderstorm Warning	LCH	Tyler	24 min
Mar 18, 8:37 PM CDT	Tornado Warning	SHV	San Augustine, Shelby	26 min
Mar 18, 8:44 PM CDT	Severe Thunderstorm Warning	SHV	Panola, Shelby	46 min
Mar 18, 8:44 PM CDT	Severe Thunderstorm Warning	SHV	Angelina, Sabine, San Augustine	61 min
Mar 18, 8:56 PM CDT	Severe Thunderstorm Warning	LCH	Hardin, Jasper, Tyler	49 min
Mar 18, 8:57 PM CDT	Severe Thunderstorm Warning	LCH	Jasper, Newton	48 min
Mar 18, 9:08 PM CDT	Severe Thunderstorm Warning	LCH	Newton	52 min
Mar 18, 9:22 PM CDT	Severe Thunderstorm Warning	SHV	Sabine	15 min
Mar 18, 9:45 PM CDT	Severe Thunderstorm Warning	LCH	Jasper, Newton, Tyler	45 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

Fort Worth, TX (KFWD), launched 12:00Z, 9.1 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 177 J/kg
Mixed-layer CIN: -144 J/kg
Mixed-layer LCL: 537 m above ground
0-6 km bulk shear: 65 kt
0-1 km storm-relative helicity: 182 m²/s²
0-3 km storm-relative helicity: 63 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.2

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 17, 8:35 PM CDT	Mesoscale Discussion	SPC	Bell, Brazos, Falls, Houston, Leon, Madison and 2 more	55 min
Mar 18, 2:33 PM CDT	Mesoscale Discussion	SPC	Archer, Baylor, Bosque, Brown, Callahan, Clay and 27 more	117 min
Mar 18, 3:31 PM CDT	Mesoscale Discussion	SPC	Anderson, Angelina, Austin, Bastrop, Bell, Brazos and 29 more	119 min
Mar 18, 5:30 PM CDT	Mesoscale Discussion	SPC	Austin, Bastrop, Caldwell, Colorado, Fayette, Travis and 2 more	2 hr
Mar 18, 6:27 PM CDT	Mesoscale Discussion	SPC	Hemphill, Lipscomb, Wheeler	3 hr

Nearby

Severe Thunderstorm Watches in Texas, 2018 Every severe thunderstorm watch in 2018

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.