Tornado Watch 899

Issued

Dec 22, 2011, 10:00 AM CST (16:00 UTC)

Expired

Dec 22, 2011, 5:00 PM CST

In force

7 hr

Issued by

the Storm Prediction Center

Largest hail expected

0.5 in

Strongest gust expected

60 kt

The Mobile radar (KMOB), 137 km from the middle of the area, began a volume at 16:00 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

40%

One or more EF2 to EF5 tornadoes

20%

Ten or more severe wind reports

40%

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%

• Mesoscale Discussion 2388Dec 22, 7:50 AM CST
• Mesoscale Discussion 2389Dec 22, 9:32 AM CST
• Mesoscale Discussion 2390Dec 22, 11:22 AM CST
• Mesoscale Discussion 2392Dec 22, 2:51 PM CST

228 
WWUS20 KWNS 221603
SEL9
SPC WW 221603
ALZ000-FLZ000-LAZ000-MSZ000-CWZ000-222300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 899
NWS STORM PREDICTION CENTER NORMAN OK
1000 AM CST THU DEC 22 2011

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

       ALABAMA
       WESTERN FLORIDA PANHANDLE
       FAR SOUTHEAST LOUISIANA
       SOUTHEAST MISSISSIPPI
       COASTAL WATERS

EFFECTIVE THIS THURSDAY MORNING AND AFTERNOON FROM 1000 AM UNTIL
500 PM CST.

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 95 STATUTE
MILES EAST AND WEST OF A LINE FROM 25 MILES EAST OF GULFPORT
MISSISSIPPI TO 10 MILES NORTH OF GADSDEN ALABAMA.  FOR A COMPLETE
DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE
(WOUS64 KWNS WOU9).

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 898...

DISCUSSION...CONVECTIVE BAND ALONG COLD FRONT FROM NEAR JAN TO W OF
NEW ORLEANS IS EXPECTED TO INTENSIFY TODAY WHILE MOVING EWD WITH
ADDITIONAL DOWNSTREAM STORM DEVELOPMENT ANTICIPATED WITHIN THE OPEN
WARM SECTOR.  LATEST VISIBLE SATELLITE SHOWS BREAKS IN THE CLOUDS
ACROSS PARTS OF SRN AL...WHICH WHEN COUPLED WITH BOUNDARY LAYER
DEWPOINTS IN THE MID 60S WILL YIELD AFTERNOON MLCAPE VALUES OF
AROUND 1000 J/KG.  THIS INSTABILITY WILL COINCIDE WITH A KINEMATIC
ENVIRONMENT FEATURING 0-1 KM SRH OF 150-300 M2/S2 AND EFFECTIVE BULK
SHEAR OF 40-50+ KT.  AS SUCH...GIVEN SETUP WILL SUPPORT SUPERCELL
AND BOW ECHO STORM MODES WITH ATTENDANT RISKS FOR A FEW TORNADOES
AND DAMAGING WINDS.

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
400. MEAN STORM MOTION VECTOR 22035.


...MEAD

Tornado Watches in Alabama, 2011Tornado Watches in Mississippi, 2011Tornado Watches in Florida, 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.