Alert archive / Oklahoma / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 774
The Storm Prediction Center issued this severe thunderstorm watch at Aug 12, 2011, 9:44 PM CDT for 35 counties in Oklahoma. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 12, 2011, 9:44 PM CDT (02:44 UTC)
- Expired
- Aug 13, 2011, 3:00 AM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 35 counties
Blaine County, OK, Caddo County, OK, Canadian County, OK, Cleveland County, OK, Comanche County, OK, Creek County, OK, Custer County, OK, Garvin County, OK, Grady County, OK, Haskell County, OK, Hughes County, OK, Kingfisher County, OK, Kiowa County, OK, Latimer County, OK, Lincoln County, OK, Logan County, OK, McClain County, OK, McIntosh County, OK, Muskogee County, OK, Nowata County, OK, Okfuskee County, OK, Oklahoma County, OK, Okmulgee County, OK, Osage County, OK, Pawnee County, OK, Payne County, OK, Pittsburg County, OK, Pontotoc County, OK, Pottawatomie County, OK, Rogers County, OK, Seminole County, OK, Tulsa County, OK, Wagoner County, OK, Washington County, OK, Washita County, OK
The radar
The Norman radar (KTLX), 36 km from the middle of the area, began a volume at 02:46 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
- 10%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
3 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 12, 10:12 PM CDT | Severe Thunderstorm Warning | OUN | Beckham, Greer, Kiowa, Washita | 63 min |
| Aug 12, 10:21 PM CDT | Severe Thunderstorm Warning | OUN | Lincoln, Logan, Oklahoma | 32 min |
| Aug 12, 11:32 PM CDT | Flash Flood Warning | TSA | Mayes, Rogers | 4 hr |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Norman, OK (KOUN), launched 00:00Z, 2.7 hours before the alert went out and 34 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
- 34 J/kg
- Mixed-layer CIN
- -393 J/kg
- Mixed-layer LCL
- 2505 m above ground
- 0-6 km bulk shear
- 25 kt
- 0-1 km storm-relative helicity
- -194 m²/s²
- 0-3 km storm-relative helicity
- -181 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 |
|---|---|---|---|---|
| Aug 12, 7:03 PM CDT | Mesoscale Discussion | SPC | Alfalfa, Blaine, Garfield, Grant, Kay, Kingfisher and 8 more | 117 min |
| Aug 12, 11:47 PM CDT | Mesoscale Discussion | SPC | Caddo, Cleveland, Coal, Comanche, Creek, Garvin and 21 more | 88 min |
Nearby
Severe Thunderstorm Watches in Oklahoma, 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.