Tornado Watch 690

Issued

Dec 20, 2012, 9:19 AM CST (15:19 UTC)

Expired

Dec 20, 2012, 6:00 PM CST

In force

9 hr

Issued by

the Storm Prediction Center

Largest hail expected

1 in

Strongest gust expected

65 kt

Two or more tornadoes

50%

One or more EF2 to EF5 tornadoes

30%

Ten or more severe wind reports

50%

One or more gusts of 65 knots or more

20%

Ten or more severe hail reports

10%

One or more hailstones of 2 inches or more

5%

Six or more combined severe hail and wind reports

95%

• Mesoscale Discussion 2189Dec 20, 8:49 AM CST
• Mesoscale Discussion 2195Dec 20, 1:31 PM CST
• Mesoscale Discussion 2198Dec 20, 5:22 PM CST

900 
WWUS20 KWNS 201524
SEL0
SPC WW 201524
ALZ000-FLZ000-GAZ000-CWZ000-210000-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 690
NWS STORM PREDICTION CENTER NORMAN OK
920 AM CST THU DEC 20 2012

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

       SOUTHEAST ALABAMA
       THE FLORIDA PANHANDLE
       SOUTHWEST GEORGIA
       COASTAL WATERS

EFFECTIVE THIS THURSDAY MORNING AND EVENING FROM 920 AM UNTIL 600
PM CST.

TORNADOES...HAIL TO 1 INCH IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 75 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 80 STATUTE
MILES EAST AND WEST OF A LINE FROM 35 MILES NORTHWEST OF ALBANY
GEORGIA TO 45 MILES SOUTH SOUTHWEST OF PANAMA CITY FLORIDA.  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.

OTHER WATCH INFORMATION...CONTINUE...WW 689...

DISCUSSION...BAND OF DISCRETE SUPERCELLS FORMING IN CORRIDOR OF
STRONG PRE-COLD FRONTAL WAA OVER SRN AL/FAR WRN FL PANHANDLE
EXPECTED TO CONTINUE EWD THROUGH MID AFTN. WHILE ATMOSPHERE OVER
CNTRL/ERN PORTIONS OF THE FL PANHANDLE AND S GA ATTM REMAINS
COMPARATIVELY STABLE RELATIVE TO POINTS W...SATELLITE DATA...SFC
OBS...AND MODEL FCSTS SUGGEST THAT APPRECIABLE DESTABILIZATION WILL
OCCUR LATER TODAY AS FRONTAL SYSTEM CONTINUES EWD AND AS MODERATE
SFC HEATING OCCURS AHEAD OF IT. GIVEN STRENGTH OF LOW TO MID-LVL
WIND PROFILES AND PRESENCE OF EXISTING LONG-LIVED STORMS...IT
APPEARS THAT A SUFFICIENT RISK FOR TORNADOES WILL BE PRESENT TO
WARRANT ISSUANCE OF A TORNADO WW. AREA N OF THIS WW WILL BE
MONITORED FOR POSSIBLE WW ISSUANCE LATER THIS MORNING OR DURING THE
EARLY AFTN SHOULD IT APPEAR THAT SIGNIFICANT DESTABILIZATION ALSO
WILL OCCUR IN CNTRL PARTS OF GA.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 65 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 400.
MEAN STORM MOTION VECTOR 23035.


...CORFIDI

Tornado Watches in Florida, 2012Tornado Watches in Georgia, 2012Tornado Watches in Alabama, 2012Every tornado watch in 2012

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.