Tornado Watch 141

Issued

Apr 15, 2011, 11:21 AM CDT (16:21 UTC)

Expired

Apr 15, 2011, 7:51 PM CDT

In force

9 hr

Issued by

the Storm Prediction Center

Largest hail expected

2 in

Strongest gust expected

60 kt

The Birmingham radar (KBMX), 119 km from the middle of the area, began a volume at 16:24 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.

Two or more tornadoes

70%

One or more EF2 to EF5 tornadoes

60%

Ten or more severe wind reports

30%

One or more gusts of 65 knots or more

30%

Ten or more severe hail reports

60%

One or more hailstones of 2 inches or more

50%

Six or more combined severe hail and wind reports

90%

• Mesoscale Discussion 436Apr 15, 10:28 AM CDT
• Mesoscale Discussion 438Apr 15, 1:30 PM CDT
• Mesoscale Discussion 440Apr 15, 3:35 PM CDT
• Mesoscale Discussion 442Apr 15, 5:57 PM CDT
• Mesoscale Discussion 443Apr 15, 6:09 PM CDT
• Mesoscale Discussion 444Apr 15, 7:16 PM CDT
• Mesoscale Discussion 445Apr 15, 7:51 PM CDT

967 
WWUS20 KWNS 151627
SEL1
SPC WW 151627
ALZ000-MSZ000-CWZ000-160200-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 141
NWS STORM PREDICTION CENTER NORMAN OK
1120 AM CDT FRI APR 15 2011

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

       CENTRAL AND SOUTHERN ALABAMA
       SOUTHEAST MISSISSIPPI
       COASTAL WATERS

EFFECTIVE THIS FRIDAY MORNING AND EVENING FROM 1120 AM UNTIL 900
PM CDT.

TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 65 STATUTE
MILES EAST AND WEST OF A LINE FROM 70 MILES NORTH OF MONTGOMERY
ALABAMA TO 145 MILES SOUTHWEST OF SELMA ALABAMA.  FOR A COMPLETE
DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE
(WOUS64 KWNS WOU1).

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.

OTHER WATCH INFORMATION...CONTINUE...WW 140...

DISCUSSION...CLUSTER OF SUPERCELLS OVER SERN MS/SWRN AL ARE EXPECTED
TO MOVE/DEVELOP NEWD ACROSS WW AREA WITHIN A DESTABILIZING BOUNDARY
LAYER IN WAKE OF RETREATING WARM FRONT.  HERE...THE COMBINATION OF
DEW POINTS RISING THROUGH THE 60S AND DIABATIC HEATING IN THE
BOUNDARY LAYER WILL YIELD AFTERNOON MLCAPE VALUES INCREASING TO
1000-2000 J/KG.  THIS INSTABILITY COUPLED WITH RATHER STRONG
LOW-LEVEL SHEAR /I.E. EFFECTIVE SRH VALUES OF 200-400 M2 PER S2/
WILL RESULT IN AN ENVIRONMENT QUITE FAVORABLE FOR SUPERCELLS CAPABLE
OF TORNADOES /SOME SIGNIFICANT/...LARGE HAIL APPROACHING 2.0-2.5
INCHES IN DIAMETER AND DAMAGING WIND GUSTS.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 24030.


...MEAD

Tornado Watches in Alabama, 2011Tornado Watches in Mississippi, 2011Every tornado watch in 2011

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.