Alert archive / Oklahoma / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 852
The Storm Prediction Center issued this severe thunderstorm watch at Sep 18, 2011, 3:30 PM CDT for 7 counties in Arkansas; 6 counties in Missouri; 30 counties in Oklahoma. It was in force for 8 hr.
The area
The outline as issued.
The facts
- Issued
- Sep 18, 2011, 3:30 PM CDT (20:30 UTC)
- Expired
- Sep 18, 2011, 11:00 PM CDT
- In force
- 8 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 43 counties
Benton County, AR, Carroll County, AR, Crawford County, AR, Franklin County, AR, Madison County, AR, Sebastian County, AR, Washington County, AR, Barry County, MO, Christian County, MO, McDonald County, MO, Newton County, MO, Stone County, MO, Taney County, MO, Adair County, OK, Atoka County, OK, Bryan County, OK, Carter County, OK, Cherokee County, OK, Choctaw County, OK, Coal County, OK, Craig County, OK, Delaware County, OK, Haskell County, OK, Hughes County, OK, Johnston County, OK, Latimer County, OK, LeFlore County, OK, Love County, OK, Marshall County, OK, Mayes County, OK, McIntosh County, OK, Murray County, OK, Muskogee County, OK, Okfuskee County, OK, Okmulgee County, OK, Ottawa County, OK, Pittsburg County, OK, Pontotoc County, OK, Pushmataha County, OK, Rogers County, OK, Seminole County, OK, Sequoyah County, OK, Wagoner County, OK
The radar
The Tulsa radar (KINX), 57 km from the middle of the area, began a volume at 20:32 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
- 50%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 70%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 95%
Warnings issued inside it
15 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 18, 4:08 PM CDT | Severe Thunderstorm Warning | TSA | Benton | 67 min |
| Sep 18, 4:24 PM CDT | Severe Thunderstorm Warning | TSA | Haskell, Latimer, LeFlore, Muskogee, Sequoyah | 66 min |
| Sep 18, 4:28 PM CDT | Severe Thunderstorm Warning | TSA | Cherokee, Muskogee, Okmulgee, Wagoner | 62 min |
| Sep 18, 4:53 PM CDT | Severe Thunderstorm Warning | OUN | Bryan, Marshall | 52 min |
| Sep 18, 5:02 PM CDT | Severe Thunderstorm Warning | SGF | Barry, McDonald | 43 min |
| Sep 18, 5:17 PM CDT | Severe Thunderstorm Warning | OUN | Atoka, Bryan, Johnston, Marshall | 43 min |
| Sep 18, 5:19 PM CDT | Tornado Warning | SGF | Barry | 26 min |
| Sep 18, 5:25 PM CDT | Severe Thunderstorm Warning | TSA | Cherokee, Muskogee, Sequoyah, Wagoner | 65 min |
| Sep 18, 5:28 PM CDT | Severe Thunderstorm Warning | TSA | Crawford, Franklin, Sebastian | 62 min |
| Sep 18, 5:33 PM CDT | Severe Thunderstorm Warning | TSA | Latimer, Pittsburg, Pushmataha | 57 min |
| Sep 18, 5:34 PM CDT | Severe Thunderstorm Warning | OUN | Atoka | 56 min |
| Sep 18, 5:40 PM CDT | Tornado Warning | SGF | Barry | 23 min |
| Sep 18, 5:42 PM CDT | Tornado Warning | TSA | Benton, Washington | 48 min |
| Sep 18, 6:03 PM CDT | Severe Thunderstorm Warning | OUN | Bryan | 57 min |
| Sep 18, 6:25 PM CDT | Severe Thunderstorm Warning | OUN | Coal, Hughes | 51 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
Springfield, MO (KSGF), launched 12:00Z, 8.5 hours before the alert went out and 184 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1001 m above ground
- 0-6 km bulk shear
- 20 kt
- 0-1 km storm-relative helicity
- 228 m²/s²
- 0-3 km storm-relative helicity
- 350 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 18, 2:45 PM CDT | Mesoscale Discussion | SPC | Benton, Crawford, Sebastian, Washington | 2 hr |
| Sep 18, 5:41 PM CDT | Severe Thunderstorm Watch | SPC | Boone, Clark, Columbia, Conway, Garland, Hempstead and 19 more | 7 hr |
| Sep 18, 6:48 PM CDT | Mesoscale Discussion | SPC | Benton, Carroll, Conway, Crawford, Garland, Howard and 11 more | 57 min |
| Sep 17, 10:17 PM CDT | Mesoscale Discussion | SPC | Atoka, Bryan, Carter, Cherokee, Cleveland, Coal and 28 more | 88 min |
| Sep 18, 3:59 PM CDT | Mesoscale Discussion | SPC | Love | 31 min |
Nearby
Severe Thunderstorm Watches in Oklahoma, 2011Severe Thunderstorm Watches in Arkansas, 2011Severe Thunderstorm Watches in Missouri, 2011Every severe thunderstorm watch in 2011
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.