Alert archive / Oklahoma / Severe Thunderstorm Watches in 2007
Severe Thunderstorm Watch 121
The Storm Prediction Center issued this severe thunderstorm watch at Apr 10, 2007, 3:40 PM CDT for 21 counties in Oklahoma; 11 counties in Texas. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 10, 2007, 3:40 PM CDT (20:40 UTC)
- Expired
- Apr 10, 2007, 10:00 PM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 32 counties
Beckham County, OK, Caddo County, OK, Carter County, OK, Comanche County, OK, Cotton County, OK, Garvin County, OK, Grady County, OK, Greer County, OK, Harmon County, OK, Jackson County, OK, Jefferson County, OK, Johnston County, OK, Kiowa County, OK, Love County, OK, Marshall County, OK, McClain County, OK, Murray County, OK, Pontotoc County, OK, Stephens County, OK, Tillman County, OK, Washita County, OK, Archer County, TX, Baylor County, TX, Clay County, TX, Cooke County, TX, Foard County, TX, Grayson County, TX, Hardeman County, TX, Knox County, TX, Montague County, TX, Wichita County, TX, Wilbarger County, TX
The radar
The Altus AFB radar (KFDR), 45 km from the middle of the area, began a volume at 20:40 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
- 30%
- Ten or more severe hail reports
- 60%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 80%
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 |
|---|---|---|---|---|
| Apr 10, 6:26 PM CDT | Severe Thunderstorm Warning | OUN | Caddo, Comanche | 34 min |
| Apr 10, 6:42 PM CDT | Tornado Warning | OUN | Grady | 33 min |
| Apr 10, 6:56 PM CDT | Tornado Warning | OUN | Stephens | 34 min |
| Apr 10, 7:11 PM CDT | Severe Thunderstorm Warning | OUN | Grady | 34 min |
| Apr 10, 7:24 PM CDT | Severe Thunderstorm Warning | OUN | Garvin, McClain | 51 min |
| Apr 10, 7:33 PM CDT | Tornado Warning | OUN | Carter, Garvin | 27 min |
| Apr 10, 7:46 PM CDT | Severe Thunderstorm Warning | OUN | Murray | 44 min |
| Apr 10, 8:03 PM CDT | Severe Thunderstorm Warning | OUN | Pontotoc | 42 min |
| Apr 10, 8:20 PM CDT | Severe Thunderstorm Warning | OUN | Cleveland, McClain | 25 min |
| Apr 10, 8:27 PM CDT | Severe Thunderstorm Warning | OUN | Johnston | 36 min |
| Apr 10, 8:43 PM CDT | Severe Thunderstorm Warning | OUN | Atoka, Coal, Hughes, Pontotoc | 47 min |
| Apr 10, 9:28 PM CDT | Severe Thunderstorm Warning | OUN | Hughes, Pontotoc | 47 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
Norman, OK (KOUN), launched 12:00Z, 8.7 hours before the alert went out and 128 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
- 480 m above ground
- 0-6 km bulk shear
- 27 kt
- 0-1 km storm-relative helicity
- 312 m²/s²
- 0-3 km storm-relative helicity
- 341 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 |
|---|---|---|---|---|
| Apr 10, 2:52 PM CDT | Mesoscale Discussion | SPC | Beckham, Caddo, Comanche, Cotton, Greer, Harmon and 5 more | 83 min |
| Apr 10, 6:02 PM CDT | Mesoscale Discussion | SPC | Carter, Comanche, Cotton, Garvin, Jefferson, Stephens | 88 min |
| Apr 10, 9:46 AM CDT | Mesoscale Discussion | SPC | Hardin, Jasper, Jefferson, Newton, Orange, Sabine | 119 min |
Nearby
Severe Thunderstorm Watches in Oklahoma, 2007Severe Thunderstorm Watches in Texas, 2007Every severe thunderstorm watch in 2007
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.