Alert archive / Georgia / Severe Thunderstorm Watches in 2015
Severe Thunderstorm Watch 86
The Storm Prediction Center issued this severe thunderstorm watch at Apr 20, 2015, 11:04 AM EDT for 28 counties in Florida; 31 counties in Georgia. It was in force for 8 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 20, 2015, 11:04 AM EDT (15:04 UTC)
- Expired
- Apr 20, 2015, 7:00 PM EDT
- In force
- 8 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 59 counties
Alachua County, FL, Baker County, FL, Bradford County, FL, Citrus County, FL, Clay County, FL, Columbia County, FL, Dixie County, FL, Duval County, FL, Flagler County, FL, Gilchrist County, FL, Hamilton County, FL, Hernando County, FL, Hillsborough County, FL, Jefferson County, FL, Lafayette County, FL, Levy County, FL, Madison County, FL, Manatee County, FL, Marion County, FL, Nassau County, FL, Pasco County, FL, Polk County, FL, Putnam County, FL, Saint Johns County, FL, Sumter County, FL, Suwannee County, FL, Taylor County, FL, Union County, FL, Appling County, GA, Atkinson County, GA, Bacon County, GA, Baker County, GA, Ben Hill County, GA, Berrien County, GA, Brantley County, GA, Brooks County, GA, Camden County, GA, Charlton County, GA, Clinch County, GA, Coffee County, GA, Colquitt County, GA, Cook County, GA, Dougherty County, GA, Echols County, GA, Glynn County, GA, Grady County, GA, Irwin County, GA, Jeff Davis County, GA, Lanier County, GA, Lee County, GA, Lowndes County, GA, Mitchell County, GA, Pierce County, GA, Thomas County, GA, Tift County, GA, Turner County, GA, Ware County, GA, Wayne County, GA, Worth County, GA
The radar
The Moody AFB radar (KVAX), 26 km from the middle of the area, began a volume at 15:06 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
- 2%
- Ten or more severe wind reports
- 50%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 50%
- One or more hailstones of 2 inches or more
- 10%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
6 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 20, 12:32 PM EDT | Severe Thunderstorm Warning | TAE | Dixie, Lafayette, Taylor | 28 min |
| Apr 20, 12:58 PM EDT | Severe Thunderstorm Warning | TAE | Dixie, Lafayette | 28 min |
| Apr 20, 3:24 PM EDT | Severe Thunderstorm Warning | JAX | Putnam | 36 min |
| Apr 20, 3:31 PM EDT | Severe Thunderstorm Warning | JAX | Marion | 44 min |
| Apr 20, 3:43 PM EDT | Severe Thunderstorm Warning | JAX | Flagler, Saint Johns | 62 min |
| Apr 20, 4:25 PM EDT | Severe Thunderstorm Warning | TBW | Hillsborough, Manatee, Pinellas | 50 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 12:00Z, 3.1 hours before the alert went out and 115 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
- 204 J/kg
- Mixed-layer CIN
- -147 J/kg
- Mixed-layer LCL
- 973 m above ground
- 0-6 km bulk shear
- 33 kt
- 0-1 km storm-relative helicity
- 56 m²/s²
- 0-3 km storm-relative helicity
- 68 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 20, 8:35 AM EDT | Mesoscale Discussion | SPC | Alachua, Baker, Bay, Bradford, Calhoun, Columbia and 16 more | 2 hr |
| Apr 20, 12:13 PM EDT | Mesoscale Discussion | SPC | Brevard, Broward, Indian River, Lake, Martin, Okeechobee and 7 more | 2 hr |
| Apr 20, 1:03 PM EDT | Severe Thunderstorm Watch | SPC | Brevard, Broward, Indian River, Lake, Martin, Miami-Dade and 7 more | 6 hr |
| Apr 20, 2:44 PM EDT | Mesoscale Discussion | SPC | Alachua, Bradford, Citrus, Clay, Duval, Flagler and 12 more | 91 min |
| Apr 20, 4:29 PM EDT | Mesoscale Discussion | SPC | Brevard, Broward, Indian River, Lake, Martin, Miami-Dade and 7 more | 2 hr |
| Apr 20, 5:24 PM EDT | Mesoscale Discussion | SPC | Broward, Hillsborough, Indian River, Manatee, Martin, Okeechobee and 4 more | 96 min |
| Apr 20, 2:09 AM EDT | Severe Thunderstorm Watch | SPC | Catoosa, Chattooga, Dade, Floyd, Gordon, Walker and 1 more | 4 hr |
| Apr 20, 3:36 AM EDT | Mesoscale Discussion | SPC | Catoosa, Chattooga, Dade, Floyd, Gordon, Murray and 2 more | 84 min |
| Apr 20, 1:03 PM EDT | Mesoscale Discussion | SPC | Banks, Clarke, Elbert, Franklin, Habersham, Hall and 7 more | 57 min |
| Apr 20, 1:23 PM EDT | Tornado Watch | SPC | Banks, Barrow, Clarke, Clayton, Cobb, Coweta and 22 more | 7 hr |
| Apr 20, 4:18 PM EDT | Mesoscale Discussion | SPC | Banks, Barrow, Clarke, Elbert, Franklin, Habersham and 9 more | 57 min |
| Apr 20, 4:36 PM EDT | Tornado Watch | SPC | Lincoln | 5 hr |
| Apr 20, 6:45 PM EDT | Mesoscale Discussion | SPC | Banks, Barrow, Clarke, DeKalb, Elbert, Forsyth and 17 more | 60 min |
Nearby
Severe Thunderstorm Watches in Georgia, 2015Severe Thunderstorm Watches in Florida, 2015Every severe thunderstorm watch in 2015
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.