000 FXUS62 KFFC 091044 AAA AFDFFC AREA FORECAST DISCUSSION...UPDATED AVIATION NATIONAL WEATHER SERVICE PEACHTREE CITY GA 543 AM EST MON NOV 9 2009 .SHORT TERM /TODAY THROUGH WEDNESDAY/... THE SHORT TERM WILL OBVIOUSLY BE DOMINATED BY IDA. FOR TODAY...HIGH PRESSURE OFF THE CAROLINAS WILL CONTINUE TO RIDGE INTO THE AREA...CONTINUING THE STABLE AIRMASS THAT HAS DOMINATED FOR SEVERAL DAYS. AS IDA APPROACHES THE GULF COAST...MOISTURE FROM THE SYSTEM WILL BEGIN OVERSPREADING THE AREA TONIGHT...WITH PRECIP LIKELY BEGINNING LATE TONIGHT. AS IDA TRANSITIONS TO EXTRATROPICAL AND INTERACTS WITH AN APPROACHING SHORTWAVE...EXPECT RAINFALL AMOUNTS TO BEGIN PILING UP DURING THE DAY ON TUESDAY. SHORT-TERM MODELS AND SREF ALL SEEM TO BE IN GENERAL AGREEMENT WITH THE SWATH OF HEAVIEST RAIN ALONG AND JUST SOUTH OF I-85...AS REFLECTED BY HPC QPF. POPS ON TUESDAY ARE PRETTY MUCH CATEGORICAL...WITH HEAVY RAIN WORDING. HAVE MADE SOME MINOR TWEAKS TO THE QPF TO INDICATE OROGRAPHIC LIFT OVER THE MOUNTAINS ON TUESDAY...AS SOUTHEASTERLY UPSLOPE WINDS MAY ENHANCE QPF. PW VALUES NEAR 1.5" ALONG WITH INCREDIBLE MOISTURE FLUX...INITIALLY COMING IN OFF THE ATLANTIC BUT SHIFTING TO A SOUTHERLY GULF TRAJECTORY TUESDAY AFTERNOON... MAY LEAD TO SOME IMPRESSIVE RAINFALL AMOUNTS. FLASH FLOOD WATCH REMAINS IN EFFECT...BUT HAVE LENGTHENED THE WATCH TO MAKE IT START A FEW HOURS EARLIER. WIDESPREAD 3-5 INCHES CAN BE EXPECTED WITH ISOLATED HIGHER AMOUNTS. AM DEFINITELY CONCERNED ABOUT HOW QUICKLY CREEKS AND RIVERS WILL RESPOND TO THE RAIN...ESPECIALLY AS WE ARE MOVING CLOSER TO WINTER WHEN RUNOFF OCCURS MORE QUICKLY. WINDS ARE LESS OF A THREAT THAN THE RAIN BUT STILL SOMEWHAT CONCERNING. CURRENT NHC TRACK HAS IDA MOVING INLAND NOT FAR FROM MOBILE AND THEN TAKING A TURN ALMOST DUE EAST IN RESPONSE TO THE APPROACHING SHORTWAVE...AND WEAKENING RAPIDLY. THE 9Z UPDATE BRINGS TROPICAL STORM FORCE WINDS INTO SOUTHERN ALABAMA. WITH FRICTION TAKEN INTO ACCOUNT DO NOT EXPECT WINDS QUITE THAT HIGH OVER OUR CWA. THE INCREASED GRADIENT ACROSS THE AREA DUE TO THE HIGH PRESSURE TO THE EAST MAY ALSO LEAD TO STRONGER WINDS. FOR NOW...WINDS REMAIN IN THE WIND ADVISORY RANGE (GENERALLY BETWEEN 20-30MPH). TOO EARLY FOR AN ADVISORY JUST YET...BUT ONE WILL LIKELY BE NEEDED. IF IDA MOVES MORE TO THE NORTHEAST WE MAY HAVE TO CONSIDER HIGH WIND WARNING. THE OTHER CONCERN IS THE INCREDIBLE AMOUNTS OF HELICITY. 15-20KT SOUTHEASTERLY WINDS AT THE SURFACE WITH 40-50KT SOUTHERLY WINDS AT 850MB LEAD TO SOMEWHERE BETWEEN 600-1000 M2/S2. NAM...WITH ITS PROJECTED TRACK MUCH FURTHER TO THE SOUTH...HAS SMALLER VALUES. PROFILES SHOULD BE MOIST ADIABATIC AND IN GENERAL VERY STABLE...SO TORNADO THREAT IS CERTAINLY MINIMIZED...BUT NOT COMPLETELY ABSENT. WILL HAVE TO WATCH TRENDS. IN ANY CASE...THE HEAVY RAIN THREAT IS CERTAINLY THE MOST SIGNIFICANT OF ALL. SOME QUESTION ABOUT HOW LONG IDA'S EFFECTS WILL LINGER. ECMWF KEEPS THE LOW FURTHER SOUTH WHEREAS THE GFS PULLS IT TO THE NORTHEAST AND DEEPENS THE LOW OFF THE CAROLINA COAST. GFS IS PROBABLY TOO FAST WITH THE SYSTEM SO HAVE LEANED MORE TOWARD THE ECMWF AND HAVE LINGERED POPS THROUGH WEDNESDAY MORNING. .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... BOTH THE GFS AND ECMWF DEVELOP AN UPPER CLOSED LOW OVER THE CAROLINAS WEDNESDAY NIGHT INTO THURSDAY. GFS TOO DEEP WITH THIS AS WELL. UPPER RIDGE FROM TEXAS TO THE GREAT LAKES ALLOWS A SURFACE HIGH TO EXTEND ACROSS THE COUNTRY. THE SURFACE GRADIENT WILL REMAIN STRONG UNTIL THE RIDGE BUILDS INTO THE AREA. TEMPERATURES WILL REMAIN FAIRLY CLOSE TO NORMAL THROUGH MOST OF THE EXTENDED AS THE RIDGE SHIFTS EAST. BY LATE IN THE WEEKEND...BOTH THE GFS AND THE NAM BRING A WEAK FRONT THROUGH THE COUNTRY. POPS WILL REMAIN MOSTLY CONFINED TO NORTHWEST GEORGIA...AS IT'S POSSIBLE THAT THE FRONT WILL FIZZLE OUT ENTIRELY BEFORE ARRIVING. TDP && .AVIATION... VFR CONDITIONS THIS MORNING WILL GIVE WAY TO VFR/MVFR CIGS MOVING IN ON MOIST SOUTHEAST FLOW...JUST ABOVE SURFACE E/NE WINDS. THE DEEP TROPICAL MOISTURE AND ONSET OF RAIN SHOULD ARRIVE BETWEEN 06-09Z TONIGHT WITH CIGS/VIS DROPPING QUICKLY THROUGH MVFR RANGE. IFR CONDITIONS EXPECTED AFTER 12Z TUESDAY WITH WIDESPREAD RA/+RA CONTINUING THROUGH MUCH OF THE DAY TOMORROW. RRH && .PRELIMINARY POINT TEMPS/POPS... ATHENS 68 55 60 51 65 / 5 90 100 70 20 ATLANTA 68 55 59 50 65 / 10 90 100 50 10 BLAIRSVILLE 67 50 58 44 61 / 5 80 100 60 20 CARTERSVILLE 68 54 59 47 64 / 5 90 100 50 10 COLUMBUS 70 62 65 55 68 / 30 100 100 30 10 GAINESVILLE 67 54 59 49 64 / 5 80 100 60 20 MACON 71 63 66 55 67 / 20 100 100 50 10 ROME 66 53 60 48 65 / 5 90 100 40 10 PEACHTREE CITY 68 58 62 50 66 / 10 90 100 50 10 VIDALIA 75 63 71 58 67 / 10 80 90 60 20 && .FFC WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH WEDNESDAY MORNING FOR THE FOLLOWING ZONES: BALDWIN...BANKS...BARROW...BARTOW... BIBB...BUTTS...CARROLL...CATOOSA...CHATTOOGA...CHEROKEE... CLARKE...CLAYTON...COBB...COWETA...CRAWFORD...DADE...DAWSON... DEKALB...DOUGLAS...FANNIN...FAYETTE...FLOYD...FORSYTH...GILMER... GORDON...GREENE...GWINNETT...HALL...HANCOCK...HARALSON... HARRIS...HEARD...HENRY...JACKSON...JASPER...JONES...LAMAR... LUMPKIN...MADISON...MERIWETHER...MONROE...MORGAN...MURRAY... MUSCOGEE...NEWTON...NORTH FULTON...OCONEE...OGLETHORPE... PAULDING...PICKENS...PIKE...POLK...PUTNAM...ROCKDALE...SOUTH FULTON...SPALDING...TALBOT...TALIAFERRO...TAYLOR...TOWNS... TROUP...UNION...UPSON...WALKER...WALTON...WARREN...WHITE... WHITFIELD...WILKES. && $$