

881 

WWUS20 KWNS 220217

SEL7

SPC WW 220217

ALZ000-KYZ000-TNZ000-220800-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 587

NWS STORM PREDICTION CENTER NORMAN OK

820 PM CST SAT DEC 21 2013



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* TORNADO WATCH FOR PORTIONS OF

  WESTERN AND NORTHERN ALABAMA

  SOUTH CENTRAL KENTUCKY

  MIDDLE TENNESSEE



* EFFECTIVE THIS SATURDAY NIGHT AND SUNDAY MORNING FROM 820 PM

  UNTIL 200 AM CST.



* PRIMARY THREATS INCLUDE...

  SEVERAL TORNADOES POSSIBLE

  SEVERAL DAMAGING WIND GUSTS TO 70 MPH LIKELY



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 55 STATUTE

MILES EAST AND WEST OF A LINE FROM 75 MILES EAST NORTHEAST OF

BOWLING GREEN KENTUCKY TO 40 MILES SOUTHEAST OF COLUMBUS

MISSISSIPPI.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).



PRECAUTIONARY/PREPAREDNESS ACTIONS...



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 583...WW 584...WW

585...WW 586...



DISCUSSION...A WELL-FORMED SQUALL LINE WILL MOVE EWD OVERNIGHT FROM

WRN TN/KY AND NRN MS INTO NW AL...MIDDLE TN AND CENTRAL KY.

LOW-LEVEL MOISTURE ADVECTION AND MIXING WILL HELP MAINTAIN A

RELATIVELY WARM AND MOIST BOUNDARY LAYER WITH SURFACE-BASED

INSTABILITY AHEAD OF THE SQUALL LINE...WHILE VERTICAL SHEAR WILL

REMAIN STRONG FOR THE NEXT SEVERAL HOURS.  A COUPLE OF TORNADOES

WILL BE POSSIBLE WITH EMBEDDED CIRCULATIONS...WHILE DAMAGING WINDS

WILL BE THE PRIMARY THREAT.



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

450. MEAN STORM MOTION VECTOR 24050.





...THOMPSON

