Alert archive / Texas / Severe Thunderstorm Watches in 2015
Severe Thunderstorm Watch 496
The Storm Prediction Center issued this severe thunderstorm watch at Aug 18, 2015, 11:03 PM CDT for 10 counties in Oklahoma; 29 counties in Texas. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 18, 2015, 11:03 PM CDT (04:03 UTC)
- Expired
- Aug 19, 2015, 5:00 AM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2.5 in
- Strongest gust expected
- 60 kt
All 39 counties
Beckham County, OK, Custer County, OK, Dewey County, OK, Ellis County, OK, Greer County, OK, Harmon County, OK, Kiowa County, OK, Roger Mills County, OK, Washita County, OK, Woodward County, OK, Armstrong County, TX, Briscoe County, TX, Carson County, TX, Castro County, TX, Childress County, TX, Collingsworth County, TX, Dallam County, TX, Deaf Smith County, TX, Donley County, TX, Floyd County, TX, Gray County, TX, Hale County, TX, Hall County, TX, Hansford County, TX, Hartley County, TX, Hemphill County, TX, Hutchinson County, TX, Lamb County, TX, Lipscomb County, TX, Moore County, TX, Motley County, TX, Ochiltree County, TX, Oldham County, TX, Potter County, TX, Randall County, TX, Roberts County, TX, Sherman County, TX, Swisher County, TX, Wheeler County, TX
The radar
The Amarillo radar (KAMA), 38 km from the middle of the area, began a volume at 04:05 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
- 5%
- 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
- 60%
Warnings issued inside it
20 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 18, 11:14 PM CDT | Severe Thunderstorm Warning | AMA | Gray | 46 min |
| Aug 18, 11:18 PM CDT | Severe Thunderstorm Warning | AMA | Lipscomb, Ochiltree | 31 min |
| Aug 18, 11:30 PM CDT | Severe Thunderstorm Warning | LUB | Castro, Swisher | 31 min |
| Aug 18, 11:37 PM CDT | Severe Thunderstorm Warning | AMA | Hemphill, Lipscomb, Roberts | 50 min |
| Aug 18, 11:41 PM CDT | Severe Thunderstorm Warning | AMA | Hartley, Oldham | 49 min |
| Aug 18, 11:54 PM CDT | Severe Thunderstorm Warning | AMA | Collingsworth, Donley, Gray, Wheeler | 59 min |
| Aug 18, 11:59 PM CDT | Severe Thunderstorm Warning | AMA | Hartley, Oldham | 46 min |
| Aug 19, 12:12 AM CDT | Severe Thunderstorm Warning | AMA | Hartley, Oldham | 47 min |
| Aug 19, 12:16 AM CDT | Severe Thunderstorm Warning | OUN | Roger Mills | 44 min |
| Aug 19, 12:21 AM CDT | Severe Thunderstorm Warning | AMA | Donley, Gray | 37 min |
| Aug 19, 12:40 AM CDT | Severe Thunderstorm Warning | AMA | Deaf Smith, Oldham, Potter | 65 min |
| Aug 19, 12:54 AM CDT | Severe Thunderstorm Warning | OUN | Roger Mills | 36 min |
| Aug 19, 1:00 AM CDT | Severe Thunderstorm Warning | OUN | Beckham, Greer | 60 min |
| Aug 19, 1:25 AM CDT | Severe Thunderstorm Warning | AMA | Deaf Smith, Oldham, Randall | 65 min |
| Aug 19, 1:37 AM CDT | Severe Thunderstorm Warning | LUB | Castro, Swisher | 53 min |
| Aug 19, 1:54 AM CDT | Severe Thunderstorm Warning | OUN | Beckham, Greer | 51 min |
| Aug 19, 1:58 AM CDT | Severe Thunderstorm Warning | AMA | Potter, Randall | 32 min |
| Aug 19, 2:23 AM CDT | Severe Thunderstorm Warning | LUB | Briscoe, Floyd, Hale, Swisher | 37 min |
| Aug 19, 2:24 AM CDT | Severe Thunderstorm Warning | AMA | Armstrong, Carson, Donley, Gray, Potter, Randall | 50 min |
| Aug 19, 2:57 AM CDT | Severe Thunderstorm Warning | LUB | Briscoe, Floyd, Hale, Swisher | 48 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
Amarillo Airport, TX (KAMA), launched 00:00Z, 4.1 hours before the alert went out and 37 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
- 2335 J/kg
- Mixed-layer CIN
- -99 J/kg
- Mixed-layer LCL
- 1537 m above ground
- 0-6 km bulk shear
- 31 kt
- 0-1 km storm-relative helicity
- 45 m²/s²
- 0-3 km storm-relative helicity
- 337 m²/s²
- Significant tornado parameter
- 0.7
- Supercell composite
- 16.5
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 18, 7:17 PM CDT | Mesoscale Discussion | SPC | Adair, Cherokee, Craig, Delaware, Mayes, Ottawa and 3 more | 88 min |
| Aug 19, 3:57 AM CDT | Mesoscale Discussion | SPC | Caddo, Canadian, Carter, Cherokee, Cleveland, Coal and 36 more | 63 min |
| Aug 18, 8:24 PM CDT | Mesoscale Discussion | SPC | Armstrong, Briscoe, Carson, Castro, Collingsworth, Deaf Smith and 9 more | 3 hr |
| Aug 19, 2:45 PM CDT | Mesoscale Discussion | SPC | Anderson, Bell, Bosque, Burnet, Cherokee, Coryell and 28 more | 3 hr |
| Aug 19, 3:25 PM CDT | Mesoscale Discussion | SPC | Bandera, Brewster, Concho, Crockett, Edwards, Gillespie and 14 more | 2 hr |
Nearby
Severe Thunderstorm Watches in Texas, 2015Severe Thunderstorm Watches in Oklahoma, 2015Every severe thunderstorm watch in 2015
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.