Alert archive / Alabama / Tornado Watches in 2007

Tornado Watch 730

October 22, 20078 counties in Alabama

The Storm Prediction Center issued this tornado watch at Oct 22, 2007, 11:14 PM CDT for 8 counties in Alabama. It was in force for 89 min.

The area

The outline as issued.

The facts

Issued
Oct 22, 2007, 11:14 PM CDT (04:14 UTC)
Expired
Oct 23, 2007, 12:43 AM CDT
In force
89 min
Issued by
the Storm Prediction Center
Largest hail expected
0.5 in
Strongest gust expected
60 kt

Counties Autauga County, AL, Bibb County, AL, Chilton County, AL, Coosa County, AL, Dallas County, AL, Elmore County, AL, Lowndes County, AL, Perry County, AL

The radar

The Birmingham radar (KBMX), 73 km from the middle of the area, began a volume at 04:13 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
20%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
5%
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.

IssuedProductOfficeCountiesLasted
Oct 22, 11:16 PM CDTTornado WarningBMXBibb, Hale, Perry29 min
Oct 22, 11:25 PM CDTTornado WarningBMXDallas, Perry35 min
Oct 23, 12:00 AM CDTTornado WarningBMXBibb, Chilton, Dallas, Perry45 min
Oct 23, 12:27 AM CDTSevere Thunderstorm WarningBMXAutauga, Chilton, Dallas33 min

The nearest sounding before it

Birmingham, AL (KBMX), launched 00:00Z, 4.2 hours before the alert went out and 74 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 2007-10-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 464 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 2007-10-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 201 square meters per square second.193958Sfc1 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
464 J/kg
Mixed-layer CIN
-1 J/kg
Mixed-layer LCL
563 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
201 m²/s²
0-3 km storm-relative helicity
241 m²/s²
Significant tornado parameter
0.3
Supercell composite
2.6

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000
WWUS20 KWNS 230411
SEL0  
SPC WW 230411
ALZ000-230900-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 730
NWS STORM PREDICTION CENTER NORMAN OK
1110 PM CDT MON OCT 22 2007

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF 

       CENTRAL ALABAMA

EFFECTIVE THIS MONDAY NIGHT AND TUESDAY MORNING FROM 1110 PM
UNTIL 400 AM CDT.

TORNADOES...HAIL TO 0.5 INCH IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 35 STATUTE
MILES EAST AND WEST OF A LINE FROM 35 MILES EAST NORTHEAST OF
CENTREVILLE ALABAMA TO 45 MILES SOUTH SOUTHWEST OF SELMA ALABAMA.
 FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU0).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

DISCUSSION...CLUSTER OF SUPERCELL THUNDERSTORMS CONTINUES TO POSE
OCCASIONAL TORNADO RISK...IN ENVIRONMENT CHARACTERIZED BY MOIST LOW
LEVEL PROFILE AND VERY STRONG VERTICAL SHEAR.  MOB/BMX VAD PROFILES
INDICATE 3KM SRH VALUES OF 300-500 M2/S2 SUGGESTING THAT THREAT OF
ISOLATED TORNADOES MAY PERSIST FOR A FEW MORE HOURS OVER A SMALL
PART OF CENTRAL AL.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 21030.


...HART

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 22, 7:29 PM CDTMesoscale DiscussionSPCMobile91 min
Oct 23, 12:43 AM CDTTornado WatchSPCAutauga, Barbour, Blount, Bullock, Butler, Calhoun and 23 more6 hr
Oct 23, 2:15 AM CDTMesoscale DiscussionSPCBarbour, Chambers, Lee, Russell90 min
Oct 23, 4:24 AM CDTMesoscale DiscussionSPCBarbour, Bullock, Calhoun, Chambers, Cherokee, Clay and 13 more96 min
Oct 23, 1:45 PM CDTMesoscale DiscussionSPCLee, Russell60 min

Nearby

Tornado Watches in Alabama, 2007Every tornado watch in 2007

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.