Alert archive / Georgia / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 174
The Storm Prediction Center issued this severe thunderstorm watch at Apr 21, 2011, 2:32 AM EDT for 57 counties in Georgia. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 21, 2011, 2:32 AM EDT (06:32 UTC)
- Expired
- Apr 21, 2011, 4:45 AM EDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 60 kt
All 57 counties
Baldwin County, GA, Banks County, GA, Barrow County, GA, Bartow County, GA, Butts County, GA, Carroll County, GA, Cherokee County, GA, Clarke County, GA, Clayton County, GA, Cobb County, GA, Coweta County, GA, Dawson County, GA, DeKalb County, GA, Douglas County, GA, Fannin County, GA, Fayette County, GA, Floyd County, GA, Forsyth County, GA, Fulton County, GA, Gilmer County, GA, Gordon County, GA, Greene County, GA, Gwinnett County, GA, Hall County, GA, Hancock County, GA, Haralson County, GA, Heard County, GA, Henry County, GA, Jackson County, GA, Jasper County, GA, Jones County, GA, Lamar County, GA, Lumpkin County, GA, Madison County, GA, Meriwether County, GA, Monroe County, GA, Morgan County, GA, Murray County, GA, Newton County, GA, Oconee County, GA, Oglethorpe County, GA, Paulding County, GA, Pickens County, GA, Pike County, GA, Polk County, GA, Putnam County, GA, Rockdale County, GA, Spalding County, GA, Taliaferro County, GA, Towns County, GA, Troup County, GA, Union County, GA, Upson County, GA, Walton County, GA, Warren County, GA, White County, GA, Wilkes County, GA
The radar
The Atlanta radar (KFFC), 96 km from the middle of the area, began a volume at 06:34 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
- 2%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 5%
- 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
- 60%
Warnings issued inside it
2 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 21, 2:46 AM EDT | Severe Thunderstorm Warning | FFC | Cobb, Douglas, Fulton, Paulding | 44 min |
| Apr 21, 3:08 AM EDT | Severe Thunderstorm Warning | FFC | Cherokee, Dawson, DeKalb, Forsyth, Fulton, Gwinnett | 52 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
Peachtre/Fal Fld, GA (KFFC), launched 00:00Z, 6.5 hours before the alert went out and 95 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
- 316 J/kg
- Mixed-layer CIN
- -171 J/kg
- Mixed-layer LCL
- 1406 m above ground
- 0-6 km bulk shear
- 17 kt
- 0-1 km storm-relative helicity
- 76 m²/s²
- 0-3 km storm-relative helicity
- 108 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 21, 2:05 AM EDT | Mesoscale Discussion | SPC | Baldwin, Barrow, Bartow, Bibb, Butts, Carroll and 39 more | 85 min |
| Apr 21, 4:09 AM EDT | Mesoscale Discussion | SPC | Clarke, Elbert, Franklin, Greene, Hart, Lincoln and 5 more | 96 min |
| Apr 21, 5:40 PM EDT | Mesoscale Discussion | SPC | Appling, Bacon, Brantley, Bryan, Bulloch, Burke and 22 more | 3 hr |
Nearby
Severe Thunderstorm Watches in Georgia, 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.