Alert archive / Georgia / Severe Thunderstorm Watches in 2017

Severe Thunderstorm Watch 285

May 27, 201719 counties in Alabama; 23 counties in Georgia; 6 counties in Tennessee

The Storm Prediction Center issued this severe thunderstorm watch at May 27, 2017, 9:07 PM CDT for 19 counties in Alabama; 23 counties in Georgia; 6 counties in Tennessee. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued
May 27, 2017, 9:07 PM CDT (02:07 UTC)
Expired
May 28, 2017, 4:58 AM CDT
In force
8 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 48 counties

Blount County, AL, Cherokee County, AL, Colbert County, AL, Cullman County, AL, DeKalb County, AL, Etowah County, AL, Fayette County, AL, Franklin County, AL, Jackson County, AL, Lamar County, AL, Lauderdale County, AL, Lawrence County, AL, Limestone County, AL, Madison County, AL, Marion County, AL, Marshall County, AL, Morgan County, AL, Walker County, AL, Winston County, AL, Banks County, GA, Bartow County, GA, Catoosa County, GA, Chattooga County, GA, Cherokee County, GA, Dade County, GA, Dawson County, GA, Fannin County, GA, Floyd County, GA, Forsyth County, GA, Gilmer County, GA, Gordon County, GA, Hall County, GA, Jackson County, GA, Lumpkin County, GA, Madison County, GA, Murray County, GA, Pickens County, GA, Towns County, GA, Union County, GA, Walker County, GA, White County, GA, Whitfield County, GA, Franklin County, TN, Giles County, TN, Lawrence County, TN, Lincoln County, TN, Moore County, TN, Wayne County, TN

The radar

The Northeast Alabama radar (KHTX), 17 km from the middle of the area, began a volume at 02:06 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
5%
Ten or more severe wind reports
40%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

23 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
May 27, 9:14 PM CDTSevere Thunderstorm WarningOHXBedford, Giles, Marshall31 min
May 27, 9:23 PM CDTSevere Thunderstorm WarningHUNFranklin, Lincoln, Moore37 min
May 27, 9:33 PM CDTSevere Thunderstorm WarningHUNFranklin, Moore27 min
May 27, 9:47 PM CDTSevere Thunderstorm WarningFFCCatoosa, Dade, Murray, Walker, Whitfield58 min
May 27, 9:55 PM CDTSevere Thunderstorm WarningHUNJackson, Madison35 min
May 27, 10:26 PM CDTSevere Thunderstorm WarningHUNDeKalb, Jackson, Madison34 min
May 28, 12:33 AM CDTSevere Thunderstorm WarningHUNColbert, Franklin, Lauderdale42 min
May 28, 12:50 AM CDTSevere Thunderstorm WarningBMXMarion70 min
May 28, 1:02 AM CDTSevere Thunderstorm WarningHUNColbert, Franklin, Lauderdale, Lawrence, Limestone28 min
May 28, 1:09 AM CDTSevere Thunderstorm WarningBMXFayette, Lamar81 min
May 28, 1:15 AM CDTSevere Thunderstorm WarningHUNDeKalb, Jackson30 min
May 28, 1:21 AM CDTSevere Thunderstorm WarningBMXWalker, Winston69 min
May 28, 1:30 AM CDTSevere Thunderstorm WarningHUNFranklin, Lawrence, Limestone, Morgan30 min
May 28, 1:51 AM CDTSevere Thunderstorm WarningHUNCullman, Lawrence, Limestone, Marshall, Morgan24 min
May 28, 2:02 AM CDTSevere Thunderstorm WarningFFCChattooga, Floyd43 min
May 28, 2:15 AM CDTSevere Thunderstorm WarningHUNCullman, Marshall, Morgan30 min
May 28, 2:22 AM CDTSevere Thunderstorm WarningBMXBlount53 min
May 28, 2:28 AM CDTSevere Thunderstorm WarningBMXJefferson, Walker77 min
May 28, 2:44 AM CDTSevere Thunderstorm WarningHUNDeKalb, Marshall31 min
May 28, 2:47 AM CDTSevere Thunderstorm WarningBMXEtowah, St. Clair58 min
May 28, 3:15 AM CDTSevere Thunderstorm WarningHUNDeKalb18 min
May 28, 3:19 AM CDTSevere Thunderstorm WarningBMXCalhoun, Cherokee56 min
May 28, 3:58 AM CDTSevere Thunderstorm WarningFFCFloyd, Haralson, Polk37 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

Nashville Metro, TN (KBNA), launched 00:00Z, 2.1 hours before the alert went out and 141 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.

Skew-T log-pSkew-T log-p diagram, Nashville Metro, TN at 00:00Z on 2017-05-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2109 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Nashville Metro, TN at 00:00Z on 2017-05-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 179 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
2109 J/kg
Mixed-layer CIN
-21 J/kg
Mixed-layer LCL
841 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
179 m²/s²
0-3 km storm-relative helicity
175 m²/s²
Significant tornado parameter
2.0
Supercell composite
12.3

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 27, 11:46 PM CDTMesoscale DiscussionSPCBibb, Calhoun, Clay, Cleburne, Fayette, Jefferson and 8 more59 min
May 28, 2:11 AM CDTMesoscale DiscussionSPCBibb, Blount, Calhoun, Cherokee, Clay, Cleburne and 23 more2 hr
May 28, 2:53 AM CDTSevere Thunderstorm WatchSPCCalhoun, Chambers, Chilton, Clay, Cleburne, Coosa and 6 more4 hr
May 28, 10:59 AM CDTMesoscale DiscussionSPCBaldwin, Covington, Escambia, Geneva, Mobile2 hr
May 27, 10:16 PM CDTMesoscale DiscussionSPCElbert, Franklin, Habersham, Hart, Rabun, Stephens89 min
May 27, 11:13 PM CDTSevere Thunderstorm WatchSPCElbert, Franklin, Habersham, Hart, Rabun, Stephens3 hr
May 28, 5:29 AM CDTMesoscale DiscussionSPCBaldwin, Bibb, Butts, Clayton, Cobb, Coweta and 21 more2 hr
May 27, 8:00 PM CDTMesoscale DiscussionSPCBeaufort, Bertie, Camden, Chowan, Dare, Edgecombe and 11 more30 min
May 27, 9:46 PM CDTMesoscale DiscussionSPCAlexander, Alleghany, Ashe, Avery, Buncombe, Burke and 33 more89 min
May 28, 1:17 AM CDTMesoscale DiscussionSPCCabarrus, Chatham, Davidson, Davie, Harnett, Hoke and 9 more58 min
May 28, 1:27 PM CDTMesoscale DiscussionSPCBertie, Camden, Chowan, Currituck, Gates, Hertford and 5 more63 min
May 28, 3:56 PM CDTMesoscale DiscussionSPCBladen, Brunswick, Columbus, Robeson2 hr
May 28, 6:06 PM CDTSevere Thunderstorm WatchSPCBladen, Brunswick, Columbus, New Hanover, Pender, Robeson4 hr
May 27, 7:02 PM CDTMesoscale DiscussionSPCBedford, Cannon, Cheatham, Coffee, Davidson, DeKalb and 18 more58 min
May 27, 9:26 PM CDTMesoscale DiscussionSPCFayette, Haywood, Lauderdale, Shelby, Tipton94 min
May 27, 9:59 PM CDTTornado WatchSPCChester, Crockett, Decatur, Fayette, Hardeman, Hardin and 7 more2 hr

Nearby

Severe Thunderstorm Watches in Georgia, 2017Severe Thunderstorm Watches in Alabama, 2017Severe Thunderstorm Watches in Tennessee, 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.