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URGENT - WINTER WEATHER MESSAGENATIONAL WEATHER SERVICE NASHVILLE TN931 AM CST TUE DEC 23 2008...FREEZING RAIN ADVISORY UNTIL 11 AM CST THIS MORNING...TNZ005>009-022>030-056>062-075-093>095-231700-/O.NEW.KOHX.ZR.Y.0004.081223T1531Z-081223T1700Z/STEWART-MONTGOMERY-ROBERTSON-SUMNER-MACON-BENTON-HOUSTON-HUMPHREYS-DICKSON-CHEATHAM-DAVIDSON-WILSON-TROUSDALE-SMITH-PERRY-HICKMAN-LEWIS-WILLIAMSON-MAURY-MARSHALL-RUTHERFORD-BEDFORD-WAYNE-LAWRENCE-GILES-931 AM CST TUE DEC 23 2008...FREEZING RAIN ADVISORY IN EFFECT UNTIL 11 AM CST THISMORNING...THE NATIONAL WEATHER SERVICE IN NASHVILLE HAS ISSUED A FREEZINGRAIN ADVISORY...WHICH IS IN EFFECT UNTIL 11 AM CST THIS MORNING.WE HAVE RECEIVED SEVERAL REPORTS OF ICY BRIDGES AND OVERPASSESIN LAWRENCE AND WAYNE COUNTIES AND IN SUMNER AND MONTGOMERY COUNTIES.ALSO...TDOT INDICATES THAT VIETNAM VETERANS HIGHWAY IN SUMNER COUNTYHAS BEEN TEMPORARILY CLOSED DOWN DUE TO SLICK ROAD CONDITIONS. DUETO THE RECENT COLD WEATHER THE GROUND TEMPERATURE IS STILL BELOW FREEZINGIN MANY AREAS. AS THE AIR TEMPERATURE WARMS THIS MORNING THISSITUATION SHOULD RELENT.A FREEZING RAIN ADVISORY MEANS THAT PERIODS OF FREEZING RAIN ORFREEZING DRIZZLE WILL CAUSE TRAVEL DIFFICULTIES. BE PREPARED FORSLIPPERY ROADS. SLOW DOWN AND USE CAUTION WHILE DRIVING.
DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1118 AM CST TUE DEC 23 2008 VALID 241200Z - 251200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS NRN MS AND NWRN AL... ...SYNOPSIS.. POTENT SHORTWAVE TROUGH WILL SWEEP RAPIDLY ENEWD FROM THE CENTRAL PLAINS INTO THE NERN STATES BY EARLY CHRISTMAS MORNING...AS 100-120 MID LEVEL JET LIFTS FROM THE BASE TO THE ERN SIDE OF THE SYSTEM. ASSOCIATED COLD FRONT WILL MOVE AHEAD OF THE TROUGH AND THROUGH THE MS/TN/OH VALLEYS DURING THE PERIOD. SUFFICIENT INSTABILITY IS EXPECTED TO EXIST ACROSS THE LOWER MS/TN VALLEYS FOR THUNDERSTORMS TO OCCUR AHEAD OF THE FRONT. ...MS/AL/TN... WIDESPREAD PRECIPITATION AND EMBEDDED CONVECTION IS EXPECTED TO BE ONGOING WEDNESDAY MORNING AHEAD OF THE ADVANCING COLD FRONT... WHICH SHOULD EXTEND FROM SERN MO SWWD INTO NRN TX AT DAYBREAK. DESPITE LACK OF DIURNAL HEATING...ADVECTION OF 60-65 SURFACE DEWPOINTS AND TEMPERATURES IN THE MID/UPPER 60S WILL PROVIDE MUCAPES FROM 400-800 J/KG FROM WRN TN SWWD INTO SWRN MS/NRN LA EARLY IN THE DAY. A SQUALL LINE IS EXPECTED TO DEVELOP ALONG/AHEAD OF THE FRONT DUE TO STRONG FRONTAL CONVERGENCE AND WINDS ABOVE THE SURFACE BECOMING MORE WSWLY AND UNIDIRECTIONAL...AS THE UPPER JET MAX PASSES THROUGH SRN MO. ASSUMING A SQUALL LINE DEVELOPS...THE STRONG MID/HIGH LEVEL WINDS WOULD PUSH THE LINE RAPIDLY EWD AT 40-50 KT. THIS FAST MOTION AND STRONG ENVIRONMENTAL WINDS... COMBINED WITH BOUNDARY LAYER DESTABILIZATION...MAY BE SUFFICIENT FOR SEVERE WINDS TO OCCUR ACROSS PORTIONS OF NRN MS AND NWRN AL. DEEP LAYER SHEAR AT 50-60 KT WOULD ALSO SUPPORT MID LEVEL ROTATION/SMALL BOWS. WHILE STRONGER FORCING WOULD ALSO FAVOR THE SQUALL LINE MOVING THROUGH WRN/MIDDLE TN...IT APPEARS THE BOUNDARY LAYER WILL REMAIN STABLE WITH A LOWER PROBABILITY FOR WIND DAMAGE. ACROSS SRN MS/LA...WHILE THE INSTABILITY WILL BE A LITTLE GREATER...MUCAPES TO 1000 J/KG BY AFTERNOON...THE FORCING AND ENVIRONMENTAL WINDS WILL BE WEAKER ACROSS THIS AREA. WHATEVER SEVERE THREAT DOES DEVELOP IS EXPECTED TO DIMINISH BY LATE AFTERNOON AS THE LOW LEVEL MASS CONVERGENCE AND UPPER LEVEL JET LIFT NEWD INTO THE OH VALLEY.
