Alert archive / Georgia / Severe Thunderstorm Watches in 2017
Severe Thunderstorm Watch 291
The Storm Prediction Center issued this severe thunderstorm watch at May 28, 2017, 2:53 AM CDT for 12 counties in Alabama; 22 counties in Georgia. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- May 28, 2017, 2:53 AM CDT (07:53 UTC)
- Expired
- May 28, 2017, 6:50 AM CDT
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 60 kt
All 34 counties
Calhoun County, AL, Chambers County, AL, Chilton County, AL, Clay County, AL, Cleburne County, AL, Coosa County, AL, Jefferson County, AL, Randolph County, AL, Shelby County, AL, St. Clair County, AL, Talladega County, AL, Tallapoosa County, AL, Butts County, GA, Carroll County, GA, Clayton County, GA, Cobb County, GA, Coweta County, GA, DeKalb County, GA, Douglas County, GA, Fayette County, GA, Fulton County, GA, Haralson County, GA, Heard County, GA, Henry County, GA, Lamar County, GA, Meriwether County, GA, Newton County, GA, Paulding County, GA, Pike County, GA, Polk County, GA, Rockdale County, GA, Spalding County, GA, Troup County, GA, Upson County, GA
The radar
The Birmingham radar (KBMX), 104 km from the middle of the area, began a volume at 07:58 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
- 10%
- One or more EF2 to EF5 tornadoes
- 5%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 10%
- 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
- 60%
Warnings issued inside it
4 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 28, 3:19 AM CDT | Severe Thunderstorm Warning | BMX | Calhoun, Cherokee | 56 min |
| May 28, 3:40 AM CDT | Severe Thunderstorm Warning | BMX | Cleburne | 50 min |
| May 28, 3:58 AM CDT | Severe Thunderstorm Warning | FFC | Floyd, Haralson, Polk | 37 min |
| May 28, 4:24 AM CDT | Severe Thunderstorm Warning | FFC | Carroll, Cobb, Douglas, Paulding | 51 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
Birmingham, AL (KBMX), launched 00:00Z, 7.9 hours before the alert went out and 104 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
- 1881 J/kg
- Mixed-layer CIN
- -85 J/kg
- Mixed-layer LCL
- 1085 m above ground
- 0-6 km bulk shear
- 39 kt
- 0-1 km storm-relative helicity
- 104 m²/s²
- 0-3 km storm-relative helicity
- 183 m²/s²
- Significant tornado parameter
- 0.9
- Supercell composite
- 10.1
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 27, 9:07 PM CDT | Severe Thunderstorm Watch | SPC | Blount, Cherokee, Colbert, Cullman, DeKalb, Etowah and 13 more | 8 hr |
| May 27, 11:46 PM CDT | Mesoscale Discussion | SPC | Bibb, Calhoun, Clay, Cleburne, Fayette, Jefferson and 8 more | 59 min |
| May 28, 2:11 AM CDT | Mesoscale Discussion | SPC | Bibb, Blount, Calhoun, Cherokee, Clay, Cleburne and 23 more | 2 hr |
| May 28, 10:59 AM CDT | Mesoscale Discussion | SPC | Baldwin, Covington, Escambia, Geneva, Mobile | 2 hr |
| May 27, 10:16 PM CDT | Mesoscale Discussion | SPC | Elbert, Franklin, Habersham, Hart, Rabun, Stephens | 89 min |
| May 27, 11:13 PM CDT | Severe Thunderstorm Watch | SPC | Elbert, Franklin, Habersham, Hart, Rabun, Stephens | 3 hr |
| May 28, 5:29 AM CDT | Mesoscale Discussion | SPC | Baldwin, Bibb, Butts, Clayton, Cobb, Coweta and 21 more | 2 hr |
Nearby
Severe Thunderstorm Watches in Georgia, 2017Severe Thunderstorm Watches in Alabama, 2017Every severe thunderstorm watch in 2017
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.