Alert archive / Mississippi / Tornado Watches in 2009
Tornado Watch 799
The Storm Prediction Center issued this tornado watch at Dec 8, 2009, 8:33 PM CST for 8 parishes in Louisiana; 33 counties in Mississippi. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Dec 8, 2009, 8:33 PM CST (02:33 UTC)
- Expired
- Dec 9, 2009, 2:00 AM CST
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 41 counties
Catahoula Parish, LA, Concordia Parish, LA, East Carroll Parish, LA, Franklin Parish, LA, Madison Parish, LA, Richland Parish, LA, Tensas Parish, LA, West Carroll Parish, LA, Adams County, MS, Amite County, MS, Attala County, MS, Carroll County, MS, Choctaw County, MS, Claiborne County, MS, Copiah County, MS, Franklin County, MS, Grenada County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Jefferson County, MS, Lawrence County, MS, Leake County, MS, Leflore County, MS, Lincoln County, MS, Madison County, MS, Montgomery County, MS, Pike County, MS, Rankin County, MS, Scott County, MS, Sharkey County, MS, Simpson County, MS, Sunflower County, MS, Walthall County, MS, Warren County, MS, Washington County, MS, Webster County, MS, Wilkinson County, MS, Winston County, MS, Yazoo County, MS
The radar
The Jackson/Brandon,MS radar (KDGX), 60 km from the middle of the area, began a volume at 02:33 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
- 30%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 20%
- 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
5 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 8, 8:41 PM CST | Tornado Warning | JAN | Attala, Leake, Neshoba, Winston | 34 min |
| Dec 8, 9:12 PM CST | Tornado Warning | JAN | Noxubee, Winston | 33 min |
| Dec 8, 9:28 PM CST | Severe Thunderstorm Warning | JAN | Holmes, Humphreys | 34 min |
| Dec 8, 10:21 PM CST | Severe Thunderstorm Warning | JAN | Choctaw, Clay, Oktibbeha, Webster | 36 min |
| Dec 9, 12:36 AM CST | Severe Thunderstorm Warning | JAN | Leake, Madison, Neshoba, Rankin, Scott | 31 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
Jackson, MS (KJAN), launched 00:00Z, 2.6 hours before the alert went out and 51 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
- 1613 J/kg
- Mixed-layer CIN
- -7 J/kg
- Mixed-layer LCL
- 554 m above ground
- 0-6 km bulk shear
- 66 kt
- 0-1 km storm-relative helicity
- 437 m²/s²
- 0-3 km storm-relative helicity
- 459 m²/s²
- Significant tornado parameter
- 4.9
- Supercell composite
- 18.6
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 8, 6:12 PM CST | Tornado Watch | SPC | Clarke, Clay, Covington, Forrest, Greene, Jasper and 14 more | 8 hr |
| Dec 8, 8:08 PM CST | Mesoscale Discussion | SPC | Attala, Choctaw, Copiah, Hinds, Lawrence, Leake and 7 more | 97 min |
| Dec 8, 9:47 PM CST | Mesoscale Discussion | SPC | Clarke, Covington, Forrest, Greene, Jasper, Jones and 12 more | 88 min |
Nearby
Tornado Watches in Mississippi, 2009Tornado Watches in Louisiana, 2009Every tornado watch in 2009
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.