Alert archive / Alabama / Severe Thunderstorm Watches in 2015

Severe Thunderstorm Watch 25

April 3, 201519 counties in Alabama; Franklin County, Lincoln County, Moore County, Tennessee

The Storm Prediction Center issued this severe thunderstorm watch at Apr 3, 2015, 6:48 PM CDT for 19 counties in Alabama; Franklin County, Lincoln County, Moore County, Tennessee. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Apr 3, 2015, 6:48 PM CDT (23:48 UTC)
Expired
Apr 3, 2015, 10:36 PM CDT
In force
4 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 22 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, Franklin County, TN, Lincoln County, TN, Moore County, TN

The radar

The Northeast Alabama radar (KHTX), 76 km from the middle of the area, began a volume at 23:50 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
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
60%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 3, 6:54 PM CDTSevere Thunderstorm WarningHUNFranklin51 min
Apr 3, 7:11 PM CDTSevere Thunderstorm WarningBMXMarion53 min
Apr 3, 7:11 PM CDTSevere Thunderstorm WarningHUNLimestone, Madison34 min
Apr 3, 7:17 PM CDTSevere Thunderstorm WarningHUNFranklin, Lincoln, Moore28 min
Apr 3, 7:27 PM CDTTornado WarningHUNMadison33 min
Apr 3, 7:29 PM CDTSevere Thunderstorm WarningHUNLimestone, Madison46 min
Apr 3, 7:41 PM CDTSevere Thunderstorm WarningHUNFranklin, Lawrence34 min
Apr 3, 7:54 PM CDTTornado WarningHUNMadison36 min
Apr 3, 7:59 PM CDTSevere Thunderstorm WarningHUNJackson, Madison31 min
Apr 3, 8:02 PM CDTSevere Thunderstorm WarningHUNFranklin28 min
Apr 3, 8:20 PM CDTSevere Thunderstorm WarningHUNJackson, Madison40 min
Apr 3, 8:26 PM CDTTornado WarningHUNJackson34 min
Apr 3, 8:29 PM CDTSevere Thunderstorm WarningHUNMadison, Marshall, Morgan31 min
Apr 3, 8:52 PM CDTSevere Thunderstorm WarningHUNDeKalb, Jackson23 min
Apr 3, 8:52 PM CDTSevere Thunderstorm WarningHUNCullman53 min
Apr 3, 8:54 PM CDTSevere Thunderstorm WarningHUNDeKalb, Jackson, Madison, Marshall36 min
Apr 3, 9:10 PM CDTTornado WarningHUNDeKalb11 min
Apr 3, 9:12 PM CDTSevere Thunderstorm WarningBMXBlount48 min
Apr 3, 9:26 PM CDTSevere Thunderstorm WarningHUNDeKalb34 min
Apr 3, 9:32 PM CDTTornado WarningHUNDeKalb28 min
Apr 3, 9:38 PM CDTSevere Thunderstorm WarningBMXCherokee37 min
Apr 3, 9:43 PM CDTTornado WarningHUNDeKalb12 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 12:00Z, 11.8 hours before the alert went out and 148 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 12:00Z on 2015-04-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 135 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 12:00Z on 2015-04-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 274 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
135 J/kg
Mixed-layer CIN
-75 J/kg
Mixed-layer LCL
990 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
274 m²/s²
0-3 km storm-relative helicity
325 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.6

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 3, 3:57 PM CDTMesoscale DiscussionSPCBlount, Colbert, Cullman, Fayette, Franklin, Lamar and 11 more93 min
Apr 3, 5:43 AM CDTMesoscale DiscussionSPCLake2 hr
Apr 3, 11:56 AM CDTMesoscale DiscussionSPCBenton, Cannon, Carroll, Cheatham, Clay, Crockett and 24 more94 min
Apr 3, 12:14 PM CDTTornado WatchSPCBenton, Carroll, Cheatham, Chester, Crockett, Davidson and 30 more8 hr
Apr 3, 2:23 PM CDTMesoscale DiscussionSPCCampbell, Cheatham, Claiborne, Clay, Davidson, DeKalb and 22 more97 min
Apr 3, 3:10 PM CDTTornado WatchSPCAnderson, Bedford, Bledsoe, Blount, Bradley, Campbell and 37 more6 hr
Apr 3, 5:54 PM CDTMesoscale DiscussionSPCCannon, Cumberland, DeKalb, Fentress, Jackson, Morgan and 9 more66 min

Nearby

Severe Thunderstorm Watches in Alabama, 2015Severe Thunderstorm Watches in Tennessee, 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.