789 FXUS62 KCHS 241442 AFDCHS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 1042 AM EDT SUN AUG 24 2014 .SYNOPSIS... A BACKDOOR COLD FRONT WILL CONTINUE TO PUSH SOUTH OF THE AREA LATE THIS MORNING...FOLLOWED BY COOLER AND DRIER HIGH PRESSURE THROUGH THE MIDDLE OF THE WEEK. TROPICAL STORM CRISTOBAL IS FORECAST TO STRENGTHEN INTO A HURRICANE AS IT PASSES WELL OFF THE U.S. SOUTHEAST COAST THROUGH MID WEEK. REFER TO THE LATEST ADVISORY ON TROPICAL DEPRESSION FOUR ISSUED BY THE NATIONAL HURRICANE CENTER. && .NEAR TERM /THROUGH TONIGHT/... THIS AFTERNOON...MID AND UPPER LVL HIGH PRESSURE WILL REMAIN CENTERED OVER THE MISSISSIPPI VALLEY WHILE A TROUGH OF LOW PRESSURE EXTENDS SOUTHWARD ALONG THE NORTHEAST COAST. AT THE SFC...A BACKDOOR COLD FRONT WILL CONTINUE TO SLIDE SOUTH OF THE REGION WITH MUCH COOLER CONDITIONS BEHIND IT AS HIGH PRESSURE BUILDS FROM THE NORTH. LOW CLOUDS ALONG WITH A PERSISTENT NORTHEAST FLOW WILL LIKELY LIMIT OVERALL HIGH TEMPS TO THE UPPER 80S AND LOWER 90S...WARMEST IN SOUTHEAST GEORGIA AWAY FROM THE COAST. LOW LVL MOISTURE WILL ALSO LINGER OVER MUCH OF THE AREA THIS AFTERNOON AND EVENING...PROVIDING A SLIGHT CHANCE TO CHANCE OF SHOWERS AND/OR THUNDERSTORMS AS A WEAK H5 SHORTWAVE SHIFTS SOUTHWARD FROM THE MID ATLANTIC STATES TO THE SOUTHEASTERN UNITED STATES. CHANCES OF PRECIP SHOULD REMAIN HIGHEST IN SOUTHEAST GEORGIA WHERE WARMER SFC TEMPS ARE EXPECTED MID AFTERNOON INTO THE EVENING. AN ENHANCED PRESSURE GRADIENT ASSOCIATED WITH HIGH PRESSURE BUILDING FROM THE NORTH WILL ALSO LEAD TO RATHER GUSTY WIND CONDITIONS OVER PARTS OF THE AREA THIS AFTERNOON...ESPECIALLY ALONG THE COAST. WINDS COULD BE AS HIGH AS 15 TO 20 MPH WITH GUSTS TO 30 MPH AT TIMES. TONIGHT...AS AN UPPER DISTURBANCE DROPS ACROSS THE AREA...THE POTENTIAL FOR ANY SHOWERS AND THUNDERSTORMS SHOULD FOCUS ACROSS SOUTHEAST GEORGIA AND PERHAPS IMMEDIATE COASTAL AREAS OF SOUTHEAST SOUTH CAROLINA THIS EVENING. THE FORECAST WILL GENERALLY INDICATE RAIN CHANCES IN THE 20-40 PERCENT RANGE ACROSS THESE AREAS AS A RESULT. ONCE SUBSIDENCE DEVELOPS AND SOMEWHAT DRIER SPREADS INTO THE AREA IN WAKE OF THE DISTURBANCE...SHOWERS SHOULD DISSIPATE OVERNIGHT BUT SOME CONVECTION COULD STILL ADVECT INLAND INTO NORTH COASTAL GEORGIA FROM THE ATLANTIC. LOWS TONIGHT WILL BE MUCH COOLER...RANGING FROM THE UPPER 60S IN NORTHWEST PORTIONS OF THE FORECAST AREA TO THE LOWER AND MID 70S FARTHER SOUTH AND CLOSER TO THE COAST. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... ALL EYES WILL BE ON TROPICAL STORM AND THEN EVENTUALLY HURRICANE CRISTOBAL AS IT MOVES NORTHWARD FROM THE BAHAMAS AND WELL OFF THE SOUTHEAST U.S. COAST. BASED ON THE LATEST FORECAST FROM THE NATIONAL HURRICANE CENTER THE STORM SHOULD BE FAR ENOUGH AWAY TO NOT PRODUCE SIGNIFICANT IMPACTS ACROSS SOUTHEAST SC/GA. HOWEVER...THE PRESSURE GRADIENT WILL REMAIN TIGHT BETWEEN THIS SYSTEM AND HIGH PRESSURE INLAND AND THIS WILL LEAD TO GUSTY WINDS...ESPECIALLY ALONG THE COAST WHICH COULD SEE GUSTS AROUND 35 MPH. OTHERWISE...TEMPERATURES WILL BE NEAR OR BELOW NORMAL THIS PERIOD...ESPECIALLY MON/TUE...WITH JUST A FEW SHOWERS FROM TIME TO TIME COMING IN OFF THE ATLANTIC. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... CRISTOBAL IS EXPECTED TO MOVE AWAY FROM THE AREA THURSDAY WITH A COLD FRONT TO POSSIBLY MOVE IN THIS WEEKEND. THUS RAIN CHANCES WILL GO BACK UP ALONG WITH TEMPS WHICH SHOULD BE SLIGHTLY ABOVE NORMAL. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... ATLANTIC MOISTURE BENEATH A LINGERING LOW LEVEL INVERSION HAS RESULTED IN STRATUS AND MVFR CEILINGS AT THE TERMINALS. CEILINGS SHOULD LIFT TO VFR LEVELS BY 16Z. EAST-NORTHEAST WINDS WILL STRENGTHEN BY AROUND MIDDAY AND COULD GUST UPWARDS OF 20-25 KT AT THE TERMINALS THROUGH THE AFTERNOON. A FEW SHOWERS ARE POSSIBLE IN THE AFTERNOON BUT WILL ONLY INDICATE THEM IN THE VICINITY OF THE TERMINALS. EXTENDED AVIATION OUTLOOK...VFR CONDITIONS WILL PREVAIL THROUGH MID WEEK...BUT IT WILL BE BREEZY EACH AFTERNOON GIVEN THE DECENT PRESSURE GRADIENT OVER THE AREA BETWEEN INLAND HIGH PRESSURE AND WHAT IS EXPECTED TO EVENTUALLY BE HURRICANE CRISTOBAL WELL OFFSHORE. && .MARINE... THIS AFTERNOON AND TONIGHT...CONDITIONS WILL DETERIORATE OVER THE COASTAL WATERS LATE THIS MORNING INTO EARLY AFTERNOON AS STRONG NORTHEAST FLOW DEVELOPS OVER THE WATERS IN RESPONSE TO HIGH PRESSURE BUILDING FROM THE NORTH. SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED ACROSS ALL WATERS...STARTING WITH THE SOUTH CAROLINA WATERS AND CHARLESTON HARBOR INITIALLY...THEN ACROSS GEORGIA COASTAL WATERS BY EARLY AFTERNOON. WINDS WILL REACH 20 TO 25 KT WITH GUSTS TO 30 KT...WHILE SEAS BUILD UPWARDS OF 4 TO 6 FT THIS AFTERNOON AND EVEN TO 6 TO 8 FT ACROSS THE OUTER GEORGIA WATERS TONIGHT. MONDAY THROUGH FRIDAY... TIGHT PRESSURE GRADIENT OVER THE AREA INTO WEDNESDAY BETWEEN INLAND HIGH PRESSURE AND WHAT IS EXPECTED TO EVENTUALLY BE HURRICANE CRISTOBAL MOVING NORTHWARD WELL OFFSHORE. STRONG NORTHEAST WINDS LOCALLY WILL LEAD TO BUILDING SEAS...PROBABLY NEAR 8 FEET IN THE OFFSHORE WATERS AND 7 FT WITHIN THE EASTERN PORTION OF THE NEAR SHORE WATERS. HOWEVER...MUCH DEPENDS ON THE EXACT STRENGTH AND TRACK OF THE TROPICAL CYCLONE SO MARINERS ARE REMINDED THAT WINDS/SEAS COULD BE HIGHER IF THE STORM IS CLOSER/STRONGER. CONDITIONS WILL IMPROVE THU/FRI AS THE STORM MOVES AWAY FROM THE AREA. RIP CURRENTS...TROPICAL STORM CRISTOBAL IS EXPECTED TO BECOME A HURRICANE AS IT MOVES NORTHWARD FROM NEAR THE BAHAMAS THROUGH MID WEEK WHILE STAYING WELL OFFSHORE. HOWEVER...THE PROLONGED PERIOD OF BRISK NORTHEAST WINDS COMBINED WITH SOME SWELL FROM CRISTOBAL WILL YIELD AN ENHANCED RISK OF RIP CURRENTS POSSIBLY THROUGH WEDNESDAY. && .TIDES/COASTAL FLOODING... TIDES WILL BE ELEVATED GIVEN THE UPCOMING NEW MOON ON MONDAY AND PROLONGED PERIOD OF BRISK NORTHEAST WINDS DUE TO HIGH PRESSURE INLAND AND LOW PRESSURE OFFSHORE. LEVELS COULD REACH ADVISORY CRITERIA DURING THE EVENING HIGH TIDE CYCLES TODAY AND MONDAY...ESPECIALLY ALONG THE SOUTH CAROLINA COAST. SOME BEACH EROSION IS ALSO LIKELY AS THIS OCCURS. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR AMZ330. SMALL CRAFT ADVISORY UNTIL 8 PM EDT TUESDAY FOR AMZ350-352. SMALL CRAFT ADVISORY UNTIL NOON EDT THURSDAY FOR AMZ374. SMALL CRAFT ADVISORY UNTIL 8 PM EDT TUESDAY FOR AMZ354. && $$ NEAR TERM...DPB SHORT TERM...RJB LONG TERM...RJB AVIATION...DPB/RJB MARINE...DPB/RJB TIDES/COASTAL FLOODING...