FXUS62 KFFC 061956
AFDFFC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
256 PM EST SUN DEC 6 2009
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
COLD HIGH PRESSURE DOMINATING THE SOUTHEAST...WITH WEST TO
SOUTHWESTERLY FLOW ALOFT. AS THE SURFACE HIGH TRANSITIONS EAST A
WEAK HYBRID DAMMING EVENT WILL SET UP...MOVING OUT JUST ALMOST AS
QUICKLY...BUT WILL LEAD TO CONTINUED COOL TEMPERATURES ESPECIALLY
OVER NORTH GEORGIA (ALBEIT WARMER THAN TODAY'S HIGHS). TIGHT
GRADIENT IN UPPER FLOW WILL LEAD TO FAST PROGRESSION OF WEAK
IMPULSES OVER THE NEXT 24-36 HOURS...THE STRONGEST OF WHICH
SHOULD PUSH THROUGH MONDAY AFTERNOON BRINGING A SLIGHT CHANCE OF
SHOWERS TO NORTHWEST GEORGIA.
STRONG UPPER TROUGH MOVING ACROSS THE ROCKIES MONDAY INTO TUESDAY
WILL LEAD TO LEE CYCLOGENESIS IN THE SOUTHERN PLAINS...MEANWHILE A
WEAK DISTURBANCE MOVING OUT OF NORTHERN MEXICO WILL ALLOW A LOW TO
DEVELOP OFF THE TEXAS GULF COAST...SPREADING MOISTURE ACROSS THE
SOUTHEAST. WARM FRONT WILL LIFT ACROSS THE SOUTHEAST BEGINNING
TUESDAY...LEADING TO A WIDESPREAD OVERRUNNING PRECIP EVENT. AS THE
PLAINS LOW HEADS EAST...IT WILL DEEPEN FAIRLY SIGNIFICANTLY (MORE
SO ON THE ECMWF THAN GFS) AND PUSH A COLD FRONT INTO THE REGION BY
LATE TUESDAY NIGHT. SURFACE HIGH AHEAD OF THE SYSTEM WILL RIDGE
DOWN THE EASTERN SLOPES OF THE APPALACHIANS AND THE LIFTING WARM
FRONT WILL SERVE AS A WEDGE FRONT BEGINNING TUESDAY. SHEAR WILL
INCREASE ACROSS THE AREA TUESDAY NIGHT AS THE STRONGLY DYNAMIC
SYNOPTIC SYSTEM APPROACHES AND INTERACTS WITH THE WEDGE FRONT. FOR
THE DAY ON TUESDAY...LOOKS LIKE MOSTLY A RAIN EVENT...BUT THERE IS
SOME INDICATION OF INSTABILITY MOVING IN TUESDAY NIGHT. SREF
PROBABILITIES NOT ALL THAT EXCITED ABOUT THE INSTABILITY...BUT
INDIVIDUAL GLOBAL RUNS INDICATE WEAK INSTABILITY...100-500 J/KG...
MOVING INTO PLACE. STRONG SURFACE WAA IN THE WARM SECTOR AND SHEAR
ASSOCIATED WITH THE RETREATING WEDGE FRONT MAY LEAD TO THE
POSSIBILITY OF SEVERE THUNDERSTORMS OVERNIGHT. SPC DAY3 OUTLOOK
ALREADY INDICATING SLIGHT RISK JUST TO OUR WEST FOR TUESDAY
AFTERNOON AND EVENING...SO WILL HAVE TO KEEP AN EYE ON THE
EVOLUTION OF THE SYSTEM. FOR NOW HAVE CONTINUED TREND OF MAINLY
SHOWERS WITH CHANCE THUNDER TUESDAY NIGHT. CURRENT INDICATIONS ARE
THAT WIDESPREAD 1-3" CAN BE EXPECTED DURING THE EVENT...SO MAY
HAVE TO ISSUE A FLOOD WATCH SOMETIME IN THE NEXT 24 HOURS.
IN GENERAL...NAM LOOKS TO SLOW DURING THE SHORT-TERM...AND WITH
GOOD AGREEMENT BETWEEN THE GFS AND ECMWF...HAVE TAKEN A BLEND OF
THE TWO.
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
COLD FRONT WILL MOVE THROUGH THE STATE EARLY WEDNESDAY. DEEP
SURFACE LOW JUST SOUTH OF THE GREAT LAKES...WITH GOOD AGREEMENT ON
BOTH GFS AND ECMWF. WRAPAROUND MOISTURE ASSOCIATED WITH THE
SURFACE LOW WILL REMAIN TO OUR NORTH...SO BASED ON THE RECENT
MODEL RUNS HAVE REMOVED SLIGHT CHANCE SNOW FROM THE MOUNTAINS
WEDNESDAY NIGHT. COOL HIGH PRESSURE BUILDS IN BEHIND THE SYSTEM
WITH GENERAL TROUGHINESS IN PLACE ALOFT...SO TEMPS REMAIN SLIGHT
BELOW AVERAGE. BY FRIDAY...GFS AND ECMWF BEGIN TO DIVERGE...BUT
12Z ECMWF IS CLOSER TO THE GFS SOLUTION THAN THE 00Z ECMWF WAS.
GFS BEGINS STREAMING MOISTURE ACROSS THE SOUTHEAST DURING THE DAY
ON FRIDAY...WITH ECMWF HOLDING OFF UNTIL FRIDAY NIGHT. BOTH
INDICATE ANOTHER WEAK HYBRID DAMMING EVENT SETTING UP. GFS BRINGS
MOST OF THE MOISTURE INTO THE REGION FRIDAY NIGHT AND SATURDAY
MORNING...ECMWF WAITS UNTIL SATURDAY TO BRING THE BULK OF THE
MOISTURE IN. WITH STRONG FLOW ALOFT...SYSTEM MOVES THROUGH FAIRLY
QUICKLY...BUT WILL AGAIN HAVE TO MONITOR HOW THIS SYSTEM EVOLVES
ESPECIALLY DUE TO THE SHEAR ASSOCIATED WITH THE CAD WEDGE.
TDP
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 32 52 39 51 46 / 0 10 10 90 90
ATLANTA 34 54 44 52 47 / 0 20 10 90 90
BLAIRSVILLE 26 48 36 49 43 / 0 20 10 90 100
CARTERSVILLE 31 50 40 52 49 / 5 20 10 90 90
COLUMBUS 36 59 47 60 54 / 0 20 10 90 90
GAINESVILLE 32 50 42 51 44 / 0 20 10 90 100
MACON 36 60 44 60 53 / 0 5 10 80 80
ROME 30 51 41 54 51 / 5 20 10 90 100
PEACHTREE CITY 31 56 40 54 50 / 0 20 10 90 90
VIDALIA 37 65 43 64 56 / 5 10 10 50 70
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
TDP
