Alert archive / Texas / Tornado Watches in 2009
Tornado Watch 278
The Storm Prediction Center issued this tornado watch at May 8, 2009, 11:48 PM CDT for 34 counties in Texas. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- May 8, 2009, 11:48 PM CDT (04:48 UTC)
- Expired
- May 9, 2009, 5:00 AM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 3 in
- Strongest gust expected
- 60 kt
All 34 counties
Camp County, TX, Collin County, TX, Cooke County, TX, Dallas County, TX, Delta County, TX, Denton County, TX, Ellis County, TX, Fannin County, TX, Franklin County, TX, Grayson County, TX, Gregg County, TX, Henderson County, TX, Hill County, TX, Hood County, TX, Hopkins County, TX, Hunt County, TX, Johnson County, TX, Kaufman County, TX, Lamar County, TX, Montague County, TX, Morris County, TX, Navarro County, TX, Parker County, TX, Rains County, TX, Red River County, TX, Rockwall County, TX, Smith County, TX, Somervell County, TX, Tarrant County, TX, Titus County, TX, Upshur County, TX, Van Zandt County, TX, Wise County, TX, Wood County, TX
The radar
The Dallas/Ft Worth radar (KFWS), 88 km from the middle of the area, began a volume at 04:49 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
- 30%
- One or more EF2 to EF5 tornadoes
- 20%
- Ten or more severe wind reports
- 40%
- 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
- 30%
- Six or more combined severe hail and wind reports
- 95%
Warnings issued inside it
8 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 9, 12:00 AM CDT | Severe Thunderstorm Warning | FWD | Cooke | 60 min |
| May 9, 12:34 AM CDT | Severe Thunderstorm Warning | FWD | Denton | 26 min |
| May 9, 12:43 AM CDT | Severe Thunderstorm Warning | FWD | Fannin, Hunt | 62 min |
| May 9, 12:44 AM CDT | Severe Thunderstorm Warning | FWD | Collin, Grayson | 61 min |
| May 9, 1:44 AM CDT | Severe Thunderstorm Warning | FWD | Fannin, Grayson | 61 min |
| May 9, 2:22 AM CDT | Severe Thunderstorm Warning | FWD | Delta, Lamar | 53 min |
| May 9, 2:33 AM CDT | Severe Thunderstorm Warning | SHV | Red River | 42 min |
| May 9, 2:45 AM CDT | Severe Thunderstorm Warning | FWD | Fannin, Hunt | 18 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
Fort Worth, TX (KFWD), launched 00:00Z, 4.8 hours before the alert went out and 68 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
- 4727 J/kg
- Mixed-layer CIN
- -57 J/kg
- Mixed-layer LCL
- 993 m above ground
- 0-6 km bulk shear
- 31 kt
- 0-1 km storm-relative helicity
- 139 m²/s²
- 0-3 km storm-relative helicity
- 189 m²/s²
- Significant tornado parameter
- 3.5
- Supercell composite
- 16.7
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 8, 9:03 PM CDT | Mesoscale Discussion | SPC | Bosque, Brown, Callahan, Clay, Coleman, Comanche and 26 more | 117 min |
| May 8, 11:19 PM CDT | Mesoscale Discussion | SPC | Bowie, Camp, Cass, Collin, Cooke, Dallas and 23 more | 86 min |
| May 9, 3:20 AM CDT | Mesoscale Discussion | SPC | Camp, Collin, Cooke, Dallas, Delta, Denton and 28 more | 55 min |
| May 9, 12:33 PM CDT | Mesoscale Discussion | SPC | Bowie, Camp, Cass, Harrison, Marion, Morris and 2 more | 57 min |
| May 9, 12:51 PM CDT | Severe Thunderstorm Watch | SPC | Bowie, Camp, Cass, Franklin, Gregg, Harrison and 6 more | 7 hr |
| May 9, 3:25 PM CDT | Mesoscale Discussion | SPC | Bowie, Cass, Marion, Morris, Red River, Titus | 65 min |
Nearby
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.