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000 FXUS62 KTAE 171301 AFDTAE AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 900 AM EDT FRI OCT 17 2008 .SYNOPSIS... 13Z WATER VAPOR AND H4 RUC ANALYSIS SHOWING AN AMPLIFYING UPPER LEVEL PATTERN THIS MORNING ACROSS THE CONUS. FROM WEST TO EAST WE FIND LONGWAVE RIDGING COVERING MUCH OF THE WESTERN U.S. AND SOUTHWEST CANADA. NORTHERN STREAM FLOW THEN DIPS INTO AMPLIFYING LONGWAVE TROUGHING ACROSS THE MID-SECTION OF THE COUNTRY...WITH THE TROUGH AXIS NOW APPROACHING THE MS RIVER VALLEY. THE OVERALL FLOW THEN FLATTENS OUT AS IT EXITS THE EASTERN SEABOARD INTO THE WESTERN ATLANTIC. CURRENTLY OVERHEAD THE FORECAST AREA WE FIND THE UPPER LEVEL RIDGING THAT HAS BROUGHT THE FAIR AND WARM WEATHER TO THE AREA THE PAST SEVERAL DAYS BEGINNING TO SINK SOUTH AND EAST IN RESPONSE TO THE APPROACHING HEIGHT FALLS TO THE NORTHWEST. AT THE SURFACE...WEAK HIGH PRESSURE REMAINS CENTERED OVER THE COASTAL WATERS THIS MORNING BUT WILL BEGIN TO SHIFT SOUTH INTO THE AFTERNOON AS A COLD FRONT APPROACHES FROM THE NORTH. COLD FRONT IS CURRENTLY LOCATED FROM THE CAROLINA COASTLINE BACK THROUGH NORTH-CENTRAL GA AND THEN SOUTHWEST IN CENTRAL AL AND SOUTHERN MS. CLOUD-SHIELD IS QUITE THICK ALONG THIS BOUNDARY WITH A LARGE AREA OF SHOWERS FROM NEAR ATLANTA TO THE BIRMINGHAM/MONTGOMERY VICINITY. FURTHER SOUTH OVER THE FORECAST AREA SKIES ARE AVERAGING PARTLY SUNNY THIS MORNING WITH AREAS OF HIGHER CLOUDS STREAMING AHEAD OF THE MAIN FRONT. && .SHORT TERM...(TODAY THROUGH SUNDAY). LITTLE CHANGE IN THE FORECAST PHILOSOPHY THROUGH SATURDAY. SLOW MOVING COLD FRONT TO OUR NORTH AND NORTHWEST WILL BEGIN TO MAKE PROGRESS SOUTHWARD LATER TODAY AS MID-LEVEL ENERGY AMPLIFIES INTO THE LOWER MS VALLEY AND SOUTHEASTERN STATES. MOST OF THE FORECAST AREA WILL REMAIN DRY TODAY WITH THE EXCEPTION OF THE FAR NORTHWEST ZONES ACROSS PORTIONS OF SE AL AND SW GA WHERE SHOWERS MAY BEGIN TO ARRIVE DURING THE LATE AFTERNOON. OTHERWISE LOOK FOR SLOWLY INCREASING UPPER LEVEL CLOUDS THROUGH THE DAY WITH HIGHS RANGING FROM THE MIDDLE AND UPPER 80S FAR EAST TO AROUND 80 FAR WEST. FRONT PUSHES SOUTHEAST ACROSS THE FORECAST AREA TONIGHT REACHING A POSITION FROM AROUND VALDOSTA TO PERRY AND OUT INTO THE EASTERN MARINE LEGS BY SUNRISE ON SATURDAY. WILL LIKELY SEE A BROKEN BAND OF MAINLY LIGHTER SHOWERS ACCOMPANY THE FRONTAL PASSAGE THROUGH THE NIGHT WITH THE RAIN ARRIVING IN THE EAST THE LATEST. GREATEST CHANCES FOR THE SHOWERS LOOK TO BE ACROSS OUR GA ZONES AS MAXIMIZED SYNOPTIC QG FORCING ASSOCIATED WITH THE MID-LEVEL HEIGHT FALLS SLIDES A BIT TO OUR NORTH. RIGHT ENTRANCE REGION DIVERGENCE ASSOCIATED WITH A 110KT UPPER LEVEL JET WILL ALSO FAVOR OUR NORTHERN AND NORTHEASTERN ZONES FOR BEST RAIN CHANCES. EITHER WAY SHOULD NOT BE A WASHOUT OF A NIGHT WITH MOST OF THE SHOWERS BEING FAIRLY BRIEF. FOR NOW WILL LEAVE THE MENTION OF THUNDER OUT OF THE FORECAST. INSTABILITY IS ONLY MARGINAL AT BEST WITH LATEST SREF PROBS AT 0% FOR EVEN 500 J/KG. COLD FRONT EXITS RAPIDLY TO THE SOUTHEAST AND OUT OF THE FORECAST AREA DURING THE FIRST HALF OF SATURDAY MORNING. GLOBAL MODELS SHOWING A VERY QUICK DRYING THROUGH THE COLUMN AS THE MID-LEVEL SHORTWAVE AXIS PASSES THE AREA. THEREFORE LOOKING FOR A DRY DAY REGIONWIDE AFTER A QUICK EARLY MORNING SHOWER DOWN TOWARD PERRY OR CROSS CITY. WITH A COOLER AND DRIER AIRMASS ARRIVING BEHIND THE FRONT LOOK FOR A MORE FALL-LIKE FEEL TO YOUR SATURDAY AFTERNOON WITH HIGH TEMPERATURES REACHING THE LOWER 80S SOUTHEAST AND THE UPPER 70S TO NEAR 80 ELSEWHERE. && .MARINE...WINDS AND SEAS WILL REMAIN LOW TODAY WITH WEAK HIGH PRESSURE OVER THE WATERS. THIS HIGH WILL MOVE EAST AND THE PRESSURE GRADIENT WILL TIGHTEN AS THE COLD FRONT APPROACHES TONIGHT. EXPECT WINDS TO PICK UP AND SEAS TO BUILD AS THE COLD FRONT MOVES INTO THE WESTERN WATERS AFTER MIDNIGHT ON SATURDAY AND REMAIN ELEVATED THROUGHOUT THE REMAINDER OF THE WEEKEND. WITH THE SURFACE RIDGE BUILDING DOWN THE EASTERN SEABOARD ON SATURDAY NIGHT...PERIODS OF ADVISORY CONDITIONS WILL BE POSSIBLE SATURDAY AND SUNDAY NIGHTS WITH WINDS IN THE 20 TO 25 KNOT RANGE AND SEAS BUILDING TO 6 TO 8 FEET WELL OFFSHORE. SATURDAY/SUNDAY AFTERNOONS SHOULD FEATURE CAUTIONARY CONDITIONS IN THE WAKE OF THE COLD FRONT. THE RIDGE SHOULD BUILD FAR ENOUGH SOUTH TO ALLOW WINDS AND SEAS TO DIMINISH BELOW HEADLINE CRITERIA BY TUESDAY AFTERNOON. && .AVIATION... PATCHY FOG HAS FORMED ACROSS MUCH OF THE CWA THIS MORNING...BUT MOST OF IT IS REMAINING AT THE MVFR LEVEL...WITH THE MORE WIDESPREAD FOG AND LOW IFR CIGS JUST OFF TO THE W OF OUR AREA. THE LONE EXCEPTION IS TLH WHICH HAS IFR GROUND FOG WHICH SHOULD BURN OFF QUICKLY AFTER SUNRISE ONCE AGAIN. THEREAFTER...VFR CONDITIONS SHOULD PREVAIL AT THE TAF SITES...WITH SOME TEMPORARY MVFR VIS IN SCT SHOWERS OUT AHEAD OF THE COLD FRONT LATER THIS AFTERNOON AND TONIGHT. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 86 60 80 51 75 / 5 40 5 0 0 PANAMA CITY 83 63 78 58 77 / 10 50 0 0 0 DOTHAN 81 56 78 50 76 / 40 60 0 0 0 ALBANY 84 58 78 50 75 / 20 60 0 0 0 VALDOSTA 87 60 78 50 75 / 5 40 10 0 0 CROSS CITY 88 63 81 53 78 / 0 20 20 0 0 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...FIRE WEATHER WATCH SATURDAY AFTERNOON FOR THE FOLLOWING ZONES: COFFEE...DALE...GENEVA...HENRY...HOUSTON. GA...NONE. FL...FIRE WEATHER WATCH SATURDAY AFTERNOON FOR THE FOLLOWING ZONES: BAY...CALHOUN...FRANKLIN...GADSDEN...GULF...HOLMES...INLAND WALTON...JACKSON...JEFFERSON...LEON...LIBERTY...WAKULLA... WASHINGTON. GM...NONE. && $$ AVIATION...GOULD MARINE...GODSEY SYNOPSIS/UPDATE...MROCZKA