Alert archive / Texas / Severe Thunderstorm Watches in 2017
Severe Thunderstorm Watch 505
The Storm Prediction Center issued this severe thunderstorm watch at Oct 21, 2017, 7:53 PM CDT for 34 counties in Texas. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Oct 21, 2017, 7:53 PM CDT (00:53 UTC)
- Expired
- Oct 22, 2017, 2:00 AM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 34 counties
Brown County, TX, Callahan County, TX, Coleman County, TX, Collin County, TX, Comanche County, TX, Cooke County, TX, Dallas County, TX, Delta County, TX, Denton County, TX, Eastland County, TX, Erath County, TX, Fannin County, TX, Grayson County, TX, Hood County, TX, Hopkins County, TX, Hunt County, TX, Jack County, TX, Johnson County, TX, Jones County, TX, Lamar County, TX, Montague County, TX, Palo Pinto County, TX, Parker County, TX, Rains County, TX, Rockwall County, TX, Runnels County, TX, Shackelford County, TX, Somervell County, TX, Stephens County, TX, Tarrant County, TX, Taylor County, TX, Throckmorton County, TX, Wise County, TX, Young County, TX
The radar
The Dallas/Ft Worth radar (KFWS), 95 km from the middle of the area, began a volume at 00:53 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
- 2%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
5 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 21, 8:29 PM CDT | Severe Thunderstorm Warning | SJT | Throckmorton | 46 min |
| Oct 21, 8:49 PM CDT | Severe Thunderstorm Warning | SJT | Jones, Shackelford, Throckmorton | 41 min |
| Oct 21, 8:52 PM CDT | Severe Thunderstorm Warning | SJT | Haskell, Throckmorton | 38 min |
| Oct 21, 9:29 PM CDT | Severe Thunderstorm Warning | SJT | Haskell, Jones, Shackelford, Throckmorton | 46 min |
| Oct 21, 10:59 PM CDT | Severe Thunderstorm Warning | SJT | Callahan, Jones, Shackelford, Taylor | 46 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 00:00Z, 0.9 hours before the alert went out and 91 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
- 1142 J/kg
- Mixed-layer CIN
- -102 J/kg
- Mixed-layer LCL
- 1889 m above ground
- 0-6 km bulk shear
- 36 kt
- 0-1 km storm-relative helicity
- 124 m²/s²
- 0-3 km storm-relative helicity
- 180 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 3.9
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 21, 8:34 PM CDT | Mesoscale Discussion | SPC | Archer, Baylor, Clay, Cooke, Denton, Fannin and 10 more | 86 min |
| Oct 21, 10:09 PM CDT | Mesoscale Discussion | SPC | Callahan, Collin, Cooke, Dallas, Denton, Eastland and 14 more | 96 min |
| Oct 21, 10:42 PM CDT | Mesoscale Discussion | SPC | Bowie, Franklin, Lamar, Red River, Titus | 93 min |
| Oct 21, 11:56 PM CDT | Severe Thunderstorm Watch | SPC | Bowie, Camp, Cass, Franklin, Marion, Morris and 4 more | 7 hr |
| Oct 22, 1:44 AM CDT | Mesoscale Discussion | SPC | Bowie, Camp, Cass, Franklin, Morris, Red River and 1 more | 91 min |
| Oct 22, 4:57 AM CDT | Mesoscale Discussion | SPC | Harrison, Panola, Rusk, Shelby | 93 min |
Nearby
Severe Thunderstorm Watches in Texas, 2017Every severe thunderstorm watch in 2017
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.