Alert archive / Alabama / Tornado Watches in 2009

Tornado Watch 176

April 19, 200928 counties in Alabama

The Storm Prediction Center issued this tornado watch at Apr 19, 2009, 8:45 PM CDT for 28 counties in Alabama. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Apr 19, 2009, 8:45 PM CDT (01:45 UTC)
Expired
Apr 20, 2009, 1:00 AM CDT
In force
4 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 28 counties

Autauga County, AL, Barbour County, AL, Bibb County, AL, Bullock County, AL, Calhoun County, AL, Chambers County, AL, Cherokee County, AL, Chilton County, AL, Clay County, AL, Cleburne County, AL, Coosa County, AL, Dallas County, AL, Elmore County, AL, Etowah County, AL, Jefferson County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Marengo County, AL, Montgomery County, AL, Perry County, AL, Pike County, AL, Randolph County, AL, Russell County, AL, Shelby County, AL, St. Clair County, AL, Talladega County, AL, Tallapoosa County, AL

The radar

The Birmingham radar (KBMX), 60 km from the middle of the area, began a volume at 01:45 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
40%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
40%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 19, 8:48 PM CDTTornado WarningBMXBullock, Macon42 min
Apr 19, 9:01 PM CDTTornado WarningBMXBlount, Calhoun, Etowah, St. Clair29 min
Apr 19, 9:12 PM CDTTornado WarningBMXAutauga, Bibb, Chilton, Dallas, Perry48 min
Apr 19, 9:13 PM CDTSevere Thunderstorm WarningBMXCherokee32 min
Apr 19, 9:21 PM CDTTornado WarningBMXLee, Macon, Russell54 min
Apr 19, 9:28 PM CDTTornado WarningBMXCalhoun, Cherokee, Etowah, St. Clair47 min
Apr 19, 9:51 PM CDTTornado WarningBMXCalhoun, Clay, Cleburne, Randolph, Talladega54 min
Apr 19, 9:51 PM CDTTornado WarningBMXLee, Russell54 min
Apr 19, 10:06 PM CDTSevere Thunderstorm WarningBMXCalhoun, Cherokee, Cleburne, Etowah39 min
Apr 19, 10:31 PM CDTSevere Thunderstorm WarningBMXAutauga, Chilton, Coosa, Elmore, Tallapoosa44 min
Apr 19, 11:13 PM CDTSevere Thunderstorm WarningBMXElmore, Tallapoosa47 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, 1.8 hours before the alert went out and 62 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, Birmingham, AL at 00:00Z on 2009-04-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 225 joules per kilogram.LCLEL10008507005003002001001 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, Birmingham, AL at 00:00Z on 2009-04-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 466 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
225 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
490 m above ground
0-6 km bulk shear
52 kt
0-1 km storm-relative helicity
466 m²/s²
0-3 km storm-relative helicity
529 m²/s²
Significant tornado parameter
0.6
Supercell composite
2.5

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 19, 7:27 PM CDTMesoscale DiscussionSPCBlount, Cullman, DeKalb, Madison, Marshall, Morgan and 1 more63 min
Apr 19, 8:19 PM CDTMesoscale DiscussionSPCAutauga, Bibb, Bullock, Calhoun, Chambers, Cherokee and 18 more56 min
Apr 19, 10:21 PM CDTMesoscale DiscussionSPCAutauga, Bullock, Calhoun, Chambers, Cherokee, Chilton and 12 more84 min
Apr 20, 12:22 AM CDTMesoscale DiscussionSPCBullock, Butler, Chambers, Crenshaw, Elmore, Lee and 6 more53 min
Apr 19, 7:51 PM CDTTornado WatchSPCBarrow, Bartow, Butts, Carroll, Catoosa, Chattooga and 42 more6 hr
Apr 19, 11:20 PM CDTMesoscale DiscussionSPCElbert, Franklin, Greene, Hart, Lincoln, McDuffie and 4 more55 min
Apr 19, 11:42 PM CDTTornado WatchSPCBaldwin, Banks, Clarke, Columbia, Elbert, Franklin and 19 more5 hr
Apr 20, 1:52 PM CDTMesoscale DiscussionSPCChatham83 min
Apr 20, 2:16 PM CDTSevere Thunderstorm WatchSPCBryan, Chatham, Effingham, Liberty, Long, McIntosh6 hr
Apr 20, 3:55 PM CDTMesoscale DiscussionSPCBryan, Bulloch, Chatham, Effingham, Evans, Liberty and 1 more95 min
Apr 20, 6:36 PM CDTMesoscale DiscussionSPCChatham84 min

Nearby

Tornado Watches in Alabama, 2009Every tornado watch in 2009

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.