Expires:No;;887133 FXUS62 KTAE 300711 AFDTAE AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 310 AM EDT SAT AUG 30 2008 .SYNOPSIS... 07Z WATER VAPOR AND H4 RUC ANALYSIS SHOWING A PROGRESSIVE NORTHERN STREAM FLOW ACROSS THE NORTHERN TIER OF STATES AND SOUTHERN CANADA. FROM WEST TO EAST WE FIND WEAK TROUGHING OVER THE PACIFIC NORTHWEST WITH RIDGING FURTHER DOWNSTREAM ACROSS THE HIGH PLAINS. THIS FLOW THEN DIPS ONCE AGAIN INTO LONGWAVE TROUGHING ACROSS THE GREAT LAKES BEFORE THE FLOW SPLITS AROUND A NORTHWARD MIGRATING CLOSED UPPER LOW OVER THE CANADIAN MARITIMES. CLOSER TO HOME WE FIND OUR AREA STILL UNDER A WEAKENING MID LEVEL TROUGH WITH RIDGING CENTERS OFF TO OUR WEST ACROSS THE CENTRAL PLAINS/SOUTHERN MS VALLEY AND ANOTHER OFF THE SOUTHEAST COAST. THESE RIDGING CENTERS ARE FORECAST TO CONGEAL OVER THE NEXT 24-48 HOURS OVER THE EASTERN U.S AND HELP STEER HURRICANE GUSTAV NORTHWESTWARD ACROSS THE CENTRAL GULF OF MEXICO. AT THE SURFACE...WEAK PRESSURE GRADIENT STILL IN PLACE ACROSS THE SOUTHEASTERN UNITED STATES. THIS GRADIENT WILL BE TIGHTENING OVER THE NEXT 24 HOURS BETWEEN HURRICANE GUSTAV WELL TO OUR SOUTH AND STRONG SURFACE HIGH PRESSURE DROPPING SOUTHEAST FROM THE GREAT LAKES TO THE MID-ATLANTIC. EAST COAST SEA-BREEZE MADE VERY GOOD PROGRESS WESTWARD THROUGH THE EVENING HOURS SUPPORTING SHOWERS AND STORMS INTO THE EASTERN BIG BEND. THESE HAVE SINCE DIMINISHED OUTSIDE A FEW CELLS IN APALACHEE BAY. && .SHORT TERM...(TODAY THROUGH MONDAY) MUCH OF THE SHORT TERM FORECAST DEPENDS ON THE EXACT TRACK AND STRENGTH OF HURRICANE GUSTAV. MODEL CONSENSUS HAS BEEN HIGHLY CLUSTERED OVER THE PAST SEVERAL RUNS IN AGREEMENT WITH THE OFFICIAL HURRICANE CENTER FORECAST WHICH SHOWS A NORTHWEST MOTION ACROSS THE CENTRAL GULF OF MEXICO SUNDAY AND SUNDAY NIGHT AND BRINGS GUSTAV TO NEAR THE NORTH-CENTRAL GULF COAST LATER MONDAY. FOR TODAY...WILL CONTINUE TO WATCH THE WEAK MID-LEVEL TROUGH OVERHEAD WEAKEN. THIS WILL ALLOW THE TWO MID/UPPER LEVEL RIDGE CENTERS DISCUSSED ABOVE TO CONGEAL FORMING A SINGLE LARGE RIDGE CENTER BY SUNDAY MORNING FROM THE MIDWESTERN STATES TO OFF THE SOUTHEAST COAST. AT THE SAME TIME WILL BE WATCHING SURFACE HIGH PRESSURE DROPPING SOUTH FROM THE GREAT LAKE STATES TOWARD THE MID-ATLANTIC. THE RESULT WILL BE AN INCREASING EASTERLY 1000-700MB FLOW THROUGH THE DAY. AREA OF MID-LEVEL DRY AIR CURRENTLY SEEN ON WV IMAGERY IS DEPICTED BY THE MODELS TO SLIDE WEST THROUGH THE DAY WITH SIGNIFICANT MOISTENING ACROSS THE SOUTHEASTERN HALF OF THE FORECAST AREA. AN EASTERLY LOW LEVEL FLOW TENDS TO FAVOR THE HIGHEST POPS ACROSS THE EASTERN FLORIDA BIG BEND. BASED ON THE DRIER MID-LEVEL AIR TO THE WEST AND THE ALREADY FAVORED RAIN AREAS ACROSS THE EAST...WILL RUN THE POP FORECAST IN A SIMILAR FASHION WITH SLIGHT CHANCE POPS FAR WEST TO CHANCE/LIKELY POPS FAR EAST. THIS TYPE OF FLOW PATTERN ALSO FAVORS THE BEST SHOWER/STORM COVERAGE ACROSS THE EASTERN ZONES LATE IN THE AFTERNOON OR EVENING AS BEST CONVERGENCE/LIFT AWAITS FOR THE ARRIVAL OF THE EAST COAST SEA-BREEZE. WITH THIS IN MIND WILL KEEP CHANCE POPS IN THE FORECAST THROUGH THE LATER EVENING HOURS ACROSS THE EASTERN FLORIDA BIG BEND AND PORTIONS OF SOUTH-CENTRAL GEORGIA. HIGH TEMPS WILL BE CLOSE TO CLIMO WITH LOWER 90S COMMON UNDER PARTLY CLOUDY SKIES. THE REMAINDER OF THE SHORT TERM PERIOD WILL BE DEPENDANT ON GUSTAV. ONCE AGAIN THE SYSTEM IS FORECAST TO MOVE NORTHWEST ACROSS THE CENTRAL GULF OF MEXICO. DEPENDING ON THE SIZE OF THE WIND FIELD/STRENGTH OF THE STORM...WOULD LEAN MORE TOWARD ONLY FRINGE EFFECTS FOR OUR AREA WITH THE BEST CHANCES FOR STRONGER WINDS AND HEAVIER RAINS OVER OUR SOUTHERN AND WESTERN MARINE ZONES. HOWEVER...STILL NEED TO KEEP A VIGILANT WATCH AS A DEVIATION TO THE RIGHT OR LEFT WILL CHANGE THE FORECAST SIGNIFICANTLY. ON THE FORECAST TRACK THE TIGHT GRADIENT BETWEEN GUSTAV AND THE HIGH CENTER TO OUR NORTHEAST SHOULD BE ENOUGH TO PRODUCE SOME GUSTY WINDS THAT ARE NOT DIRECTLY ASSOCIATED WITH THE HURRICANE. THESE WINDS WILL BE MOST EVIDENT ALONG COASTAL AREAS. IN TERMS OF RAIN CHANCES SUNDAY INTO MONDAY. BEST STRATEGY AT THIS POINT IS TO TAKE AN ENSEMBLE APPROACH WHICH WILL RESULT IN MAINLY CHANCE POPS FOR SCT SHOWER AND STORMS THROUGH THE PERIOD. HIGHEST POPS WILL BE ACROSS THE COASTAL ZONES OF THE FLORIDA PANHANDLE IN CLOSER PROXIMITY TO THE FORECAST TRACK...WITH PERHAPS POPS IN THE LIKELY CATEGORY OVER THE WESTERN MARINE ZONES. IT SHOULD BE NOTED THAT WE OFTEN SEE A BAND OF SUBSIDENCE ON THE FRIDGES OF STRONGER TROPICAL SYSTEMS THAT CAN PROVIDE VARYING DEGREES OF CONVECTIVE SUPPRESSION. SIMPLY TOO EARLY AND UNCERTAIN AT THIS TIME TO START ADDING THIS COMPONENT INTO THE FORECAST. && .LONG TERM (TUESDAY-SATURDAY)... CONFIDENCE IS FIRMING UP WITH RESPECT TO GUSTAV, AT LEAST AS FAR AS THE TRACK GOES. THE LATEST FORECAST TRACK HAS GUSTAV MAKING LANDFALL OVER S CENTRAL LA MON NIGHT. THE LATEST (00Z) GFS IS VERY CLOSE TO THE OFFICIAL TRACK AND WILL BE THE MODEL OF CHOICE THROUGH THU. AFTER THAT TIME, WE HAVE TO START DEALING WITH POTENTIAL INFLUENCES FROM HANNA. THE 29/12Z EURO TAKES A VERY HEALTHY LOOKING HANNA ACROSS FAR S FL WED NIGHT INTO THU AND THEN BEE LINES IT NWWD TO DESTIN FRI MORNING. THE GFS HAS SHOWN TERRIBLE RUN TO RUN CONSISTENCY. FOR EXAMPLE THE 29/18Z RUN BROUGHT HANNA TO PNS NEXT SAT. THE 00Z TAKE IT TO THE CAROLINAS. THE OFFICIAL COORDINATED TPC/HPC TRACK FROM YESTERDAY IS SLOWER TO BRING HANNA WWD ACROSS THE BAHAMAS, BUT DOES SHOW IT APPROACHING THE FL STRAITS FRI MORNING. THIS IS CLOSE TO THE 18Z GFS AND SO WE WILL USE THIS MODEL'S WIND FIELDS FOR THU NIGHT AND FRI. FOR DAY 8, WILL TRY TO EXTRAPOLATE FROM THE COORDINATED POSITION. && .AVIATION... PERIODS OF MVFR VSBY CAN BE EXPECTED AT ALL OF THE TERMINALS UNTIL AROUND SUNRISE. FOR THE DAYTIME HOURS TODAY, KEPT IN SOME HAZE AT PFN AND ABY. CONVECTIVE COVERAGE SHOULD BE HIGH ENOUGH TO WARRANT PROB GROUPS FOR ABY, TLH, AND VLD WITH CONFIDENCE HIGHEST AT VLD. && .MARINE... EASTERLY FLOW WILL BEGIN TO INCREASE THROUGH TODAY AS THE PRESSURE GRADIENT TIGHTENS BETWEEN BUILDING HIGH PRESSURE TO OUR NORTH AND HURRICANE GUSTAV TO THE SOUTH. WINDS AND SEAS REACH CAUTIONARY LEVELS TONIGHT AND ADVISORY LEVELS BY EARLY SUNDAY. AS HURRICANE GUSTAV MOVES INTO THE CENTRAL GULF OF MEXICO LATER SUNDAY INTO MONDAY EXPECT THE TROPICAL STORM CONDITIONS WILL BECOME POSSIBLE...ESPECIALLY ACROSS THE SOUTHERN AND WESTERN MARINE LEGS IN CLOSER PROXIMITY TO THE FORECAST TRACK OF THE STORM. SIGNIFICANT SWELL IS EXPECTED TO BEGIN PROPAGATING INTO THE MARINE AREA DURING THIS TIME WITH OFFSHORE SEAS ANTICIPATED TO REACH 10 FEET OR MORE. WINDS AND SEAS WILL GRADUALLY BEGIN TO SUBSIDE INTO THE MIDDLE PART OF NEXT WEEK && .FIRE WEATHER...NO CONCERNS. && .HYDROLOGY... MANY AREA RIVERS REMAIN AT OR ABOVE FLOOD STAGE. FOR SPECIFIC INFORMATION ON CURRENT AND FORECAST STAGES AT EACH RIVER POINT CONSULT THE TALLAHASSEE AREA AHPS (ADVANCED HYDROLOGIC PREDICTION SERVICE) PAGE AT HTTP://AHPS.SRH.NOAA.GOV/INDEX.PHP?WFO=TAE. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 92 73 90 74 89 / 30 30 40 30 50 PANAMA CITY 92 75 89 76 87 / 30 20 50 40 50 DOTHAN 92 72 90 73 89 / 20 20 40 20 40 ALBANY 93 72 91 73 90 / 30 20 30 20 40 VALDOSTA 92 72 90 73 90 / 40 30 40 20 40 CROSS CITY 92 73 90 74 90 / 40 40 40 30 50 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. GM...SMALL CRAFT ADVISORY FROM 8 AM SUNDAY TO 8 PM EDT MONDAY FOR THE FOLLOWING ZONES: COASTAL WATERS FROM OCHLOCKONEE RIVER TO APALACHICOLA FL OUT TO 20 NM...COASTAL WATERS FROM APALACHICOLA TO DESTIN FL OUT 20 NM...WATERS FROM SUWANNEE RIVER TO APALACHICOLA FL FROM 20 TO 60 NM...WATERS FROM APALACHICOLA TO DESTIN FL FROM 20 TO 60 NM. && $$ LONG TERM/FIRE WX/AVIATION...WOOL SYNOPSIS/SHORT TERM/MARINE...MROCZKA