Alert archive / Texas / Severe Thunderstorm Watches in 2020
Severe Thunderstorm Watch 482
The Storm Prediction Center issued this severe thunderstorm watch at Sep 1, 2020, 3:46 PM CDT for 8 counties in Oklahoma; 23 counties in Texas. It took effect at Sep 1, 2020, 3:51 PM CDT. It was in force for 8 hr.
The area
The outline as issued.
The facts
- Issued
- Sep 1, 2020, 3:46 PM CDT (20:46 UTC)
- In effect from
- Sep 1, 2020, 3:51 PM CDT
- Expired
- Sep 2, 2020, 12:00 AM CDT
- In force
- 8 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 31 counties
Beaver County, OK, Beckham County, OK, Ellis County, OK, Greer County, OK, Harmon County, OK, Harper County, OK, Roger Mills County, OK, Woodward County, OK, Armstrong County, TX, Briscoe County, TX, Carson County, TX, Childress County, TX, Collingsworth County, TX, Cottle County, TX, Crosby County, TX, Dickens County, TX, Donley County, TX, Floyd County, TX, Gray County, TX, Hall County, TX, Hemphill County, TX, Hutchinson County, TX, King County, TX, Lipscomb County, TX, Motley County, TX, Ochiltree County, TX, Potter County, TX, Randall County, TX, Roberts County, TX, Swisher County, TX, Wheeler County, TX
The radar
The Amarillo radar (KAMA), 136 km from the middle of the area, began a volume at 20:50 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
- 30%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 50%
- One or more hailstones of 2 inches or more
- 40%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
12 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 1, 5:09 PM CDT | Severe Thunderstorm Warning | AMA | Deaf Smith, Oldham, Potter, Randall | 37 min |
| Sep 1, 5:12 PM CDT | Severe Thunderstorm Warning | AMA | Armstrong, Donley, Randall | 78 min |
| Sep 1, 5:14 PM CDT | Severe Thunderstorm Warning | OUN | Ellis, Harper, Woodward | 46 min |
| Sep 1, 5:30 PM CDT | Flash Flood Warning | AMA | Roberts | 5 hr |
| Sep 1, 6:03 PM CDT | Severe Thunderstorm Warning | AMA | Hutchinson, Roberts | 57 min |
| Sep 1, 6:05 PM CDT | Severe Thunderstorm Warning | AMA | Potter | 55 min |
| Sep 1, 6:14 PM CDT | Severe Thunderstorm Warning | LUB | Briscoe, Childress, Hall | 61 min |
| Sep 1, 6:18 PM CDT | Severe Thunderstorm Warning | AMA | Armstrong, Collingsworth, Donley | 57 min |
| Sep 1, 6:49 PM CDT | Tornado Warning | LUB | Briscoe, Hall | 26 min |
| Sep 1, 7:08 PM CDT | Severe Thunderstorm Warning | LUB | Briscoe, Hall | 67 min |
| Sep 1, 7:51 PM CDT | Severe Thunderstorm Warning | LUB | Childress, Cottle, Hall, Motley | 54 min |
| Sep 1, 7:53 PM CDT | Severe Thunderstorm Warning | AMA | Carson, Gray, Hutchinson, Roberts | 53 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 12:00Z, 8.8 hours before the alert went out and 135 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
- 100 J/kg
- Mixed-layer CIN
- -136 J/kg
- Mixed-layer LCL
- 1063 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 8 m²/s²
- 0-3 km storm-relative helicity
- 17 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.2
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 31, 8:37 PM CDT | Mesoscale Discussion | SPC | Caddo, Canadian, Cleveland, Comanche, Cotton, Craig and 17 more | 83 min |
| Aug 31, 11:39 PM CDT | Mesoscale Discussion | SPC | Atoka, Bryan, Carter, Cleveland, Coal, Garvin and 12 more | 96 min |
| Sep 1, 2:35 PM CDT | Mesoscale Discussion | SPC | Ellis, Harmon, Roger Mills | 2 hr |
| Sep 1, 6:29 PM CDT | Mesoscale Discussion | SPC | Beaver, Beckham, Dewey, Ellis, Harper, Roger Mills and 1 more | 91 min |
Nearby
Severe Thunderstorm Watches in Texas, 2020Severe Thunderstorm Watches in Oklahoma, 2020Every severe thunderstorm watch in 2020
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.