Alert archive / Georgia / Tornado Watches in 2009
Tornado Watch 811
The Storm Prediction Center issued this tornado watch at Dec 25, 2009, 5:01 AM EST for 26 counties in Georgia; 14 counties in South Carolina. It was in force for 9 hr.
The area
The outline as issued.
The facts
- Issued
- Dec 25, 2009, 5:01 AM EST (10:01 UTC)
- Expired
- Dec 25, 2009, 2:00 PM EST
- In force
- 9 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 0.5 in
- Strongest gust expected
- 60 kt
All 40 counties
Bryan County, GA, Bulloch County, GA, Burke County, GA, Candler County, GA, Chatham County, GA, Dodge County, GA, Effingham County, GA, Emanuel County, GA, Evans County, GA, Glascock County, GA, Jefferson County, GA, Jenkins County, GA, Johnson County, GA, Laurens County, GA, Liberty County, GA, Long County, GA, McIntosh County, GA, Montgomery County, GA, Richmond County, GA, Screven County, GA, Tattnall County, GA, Telfair County, GA, Toombs County, GA, Treutlen County, GA, Washington County, GA, Wheeler County, GA, Aiken County, SC, Allendale County, SC, Bamberg County, SC, Barnwell County, SC, Beaufort County, SC, Berkeley County, SC, Calhoun County, SC, Charleston County, SC, Clarendon County, SC, Colleton County, SC, Dorchester County, SC, Hampton County, SC, Jasper County, SC, Orangeburg County, SC
The radar
The Charleston,SC radar (KCLX), 55 km from the middle of the area, began a volume at 10:02 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
- 50%
- One or more EF2 to EF5 tornadoes
- 40%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 10%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
1 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 25, 5:29 AM EST | Severe Thunderstorm Warning | FFC | Laurens, Montgomery, Telfair, Treutlen, Wheeler | 46 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
Jacksonville, FL (KJAX), launched 00:00Z, 10.0 hours before the alert went out and 218 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
- 103 J/kg
- Mixed-layer CIN
- -12 J/kg
- Mixed-layer LCL
- 860 m above ground
- 0-6 km bulk shear
- 47 kt
- 0-1 km storm-relative helicity
- 102 m²/s²
- 0-3 km storm-relative helicity
- 215 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 24, 10:45 PM EST | Mesoscale Discussion | SPC | Decatur, Seminole | 2 hr |
| Dec 25, 3:27 AM EST | Mesoscale Discussion | SPC | Atkinson, Berrien, Brooks, Clinch, Coffee, Cook and 5 more | 63 min |
| Dec 25, 3:46 AM EST | Tornado Watch | SPC | Appling, Atkinson, Bacon, Berrien, Brantley, Brooks and 13 more | 7 hr |
| Dec 25, 4:41 AM EST | Mesoscale Discussion | SPC | Appling, Bryan, Bulloch, Burke, Camden, Candler and 24 more | 64 min |
| Dec 25, 7:27 AM EST | Mesoscale Discussion | SPC | Appling, Atkinson, Bacon, Brantley, Bryan, Bulloch and 27 more | 93 min |
| Dec 25, 10:26 AM EST | Mesoscale Discussion | SPC | Appling, Bacon, Brantley, Camden, Charlton, Glynn and 3 more | 64 min |
| Dec 25, 11:39 AM EST | Mesoscale Discussion | SPC | Bryan, Chatham, Effingham, Liberty, McIntosh | 66 min |
Nearby
Tornado Watches in Georgia, 2009Tornado Watches in South Carolina, 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.