FXUS62 KCHS 060903 AFDCHS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 403 AM EST FRI DEC 6 2013 ...NEAR RECORD WARMTH TO PERSIST TODAY... .SYNOPSIS... ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH TONIGHT. A COLD FRONT WILL MOVE SOUTH THROUGH THE AREA SATURDAY AFTERNOON AND STALL TO THE SOUTH THROUGH SUNDAY. A WARM FRONT WILL THEN LIFT NORTH LATE SUNDAY NIGHT AND MONDAY...BEFORE A COLD FRONT MOVES THROUGH TUESDAY. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT FOR THE MIDDLE OF NEXT WEEK. && .NEAR TERM /THROUGH TODAY/... THROUGH SUNRISE...HIGH CLOUDS AND 20-25 KT WINDS ATOP THE BOUNDARY LAYER HAVE KEPT FOG AND EVEN STRATUS AT BAY SO FAR THIS MORNING...DESPITE INCREASING LOW-LEVEL MOISTURE. SOME CLEARING/THINNING OF THE HIGH CLOUD CANOPY IS OCCURRING ACROSS SOUTHEAST GEORGIA WHICH MAY SUPPORT THE FORMATION OF SOME LOCALLY DENSE FOG PRIOR TO SUNRISE...MAINLY SOUTH OF I-16. ANOTHER CONCERN IS ALONG THE COAST WHERE PILOT BOAT...GOES-EAST CLOUD THICKNESS PRODUCTS AND A TIMELY NIGHT TIME VISIBLE SATELLITE IMAGE FROM THE POLAR ORBITING VIIRS PACKAGE INDICATE SEA FOG IS BECOMING A LITTLE MORE WIDESPREAD OVER THE NEARSHORE WATERS. SOUTH TO SOUTHWEST WINDS MAY ADVECT SOME OF THIS FOG ONSHORE...MAINLY FROM TYBEE ISLAND NORTHEAST ALONG THE LOWER SOUTH CAROLINA COAST. ITS UNCLEAR EXACTLY HOW WIDESPREAD THE SEA FOG IS OFFSHORE WITH THE LACK OF OBSERVATIONS...BUT WOULD NOT BE SURPRISED TO SEE A LITTLE DENSE SEA FOG AFFECT THE COASTAL COMMUNITIES OVER THE NEXT SEVERAL HOURS. IT WILL BE A WARM START TO THE DAY WITH TEMPERATURES ONLY BOTTOMING OUT IN THE MID-UPPER 60S WITH A FEW LOWER 60S INLAND. TODAY...UPPER RIDGING WILL SLOWLY BEGIN TO BREAK DOWN TODAY AS A SERIES OF SHORTWAVES MOVING ACROSS THE MISSISSIPPI VALLEY STEADILY CARVE AWAY AT ITS WESTERN FLANK. AT THE SURFACE...ATLANTIC HIGH PRESSURE WILL HOLD ITS INFLUENCE OVER THE AREA YIELDING ONE MORE DAY OF NEAR RECORD WARMTH. LOW-LEVEL THICKNESS SCHEMES SUPPORT HIGHS IN THE LOWER 80S FOR MOST LOCATIONS AWAY FROM THE BEACHES THIS AFTERNOON...WHICH WILL PLACE THE HIGH TEMPERATURE RECORDS AT THE CHARLESTON AND SAVANNAH AIRPORTS IN JEOPARDY. BEACH LOCATIONS WILL REMAIN CONSIDERABLY COOLER...STRUGGLING TO REACH THE UPPER 60S. SKIES WILL GENERALLY BE PARTLY TO MOSTLY CLOUDY...ALTHOUGH SOME OF THE HIGHER RESOLUTION GUIDANCE SUGGEST THERE COULD BE A FEW HOURS OF MORE SUN THAN CLOUDS FOR A TIME THIS AFTERNOON. DRY WEATHER WILL CONTINUE WITH LITTLE PROSPECTS FOR MEASURABLE RAINFALL. BEACH LOCATIONS COULD REMAIN A BIT HAZY/FOGGY THROUGH THE DAY WITH CONDITIONS FAVORING CONTINUED SEA FOG FORMATION WITHIN THE UNSEASONABLY WARM/MOIST AIRMASS. && .SHORT TERM /TONIGHT THROUGH MONDAY/... TONIGHT...HIGH PRESSURE WILL SLOWLY MOVE OFFSHORE TONIGHT AS A COLD FRONT APPROACHES FROM THE WEST. WEAK WARM AIR ADVECTION COUPLED WITH 25-30 KT OF LOW-LEVEL JETTING ATOP THE BOUNDARY LAYER WILL KEEP THE ATMOSPHERE FAIRLY MIXED OVERNIGHT. THIS WILL YIELD ANOTHER WARM NIGHT WITH LOWS GENERALLY IN THE MID 60S...WITH A FEW UPPER 60S POSSIBLE. THE BEST CHANCES FOR MEASURABLE RAINFALL WILL REMAIN WELL TO THE WEST OVERNIGHT COINCIDENT WITH THE STRONGEST PRE-FRONTAL ISENTROPIC ASSENT...ALTHOUGH CHANCES WILL BE INCREASING FROM WEST-EAST AS SUNRISE APPROACHES. THE RECORD HIGH MINIMUMS FOR ALL THREE CLIMATE SITES COULD BE APPROACHED OR BROKEN. SATURDAY...THE COLD FRONT WILL GRADUALLY DESCEND THROUGH THE FORECAST AREA...EVENTUALLY STALLING TO THE SOUTH AND EAST AS IT RUNS INTO STRONG UPPER RIDGING CENTERED OVER THE BAHAMAS. THE HIGHEST RAIN CHANCES OF THE PERIOD HAVE BEEN ADVERTISED FOR SATURDAY AND SATURDAY NIGHT IN ASSOCIATION WITH CONVERGENCE ALONG THE FRONTAL ZONE...FOLLOWED BY INCREASING ISENTROPIC LIFT WITHIN A RAPIDLY DEVELOPING HIGH PRESSURE WEDGE IN THE WAKE OF THE FRONT. TEMPERATURES WILL BE ABLE TO REACH THE LOW TO MID 70S AHEAD OF THE FRONT...BEFORE COOLING QUICKLY DURING THE EVENING HOURS. LOW TEMPERATURES WILL RANGE FROM THE UPPER 40S INLAND TO THE MID 50S SOUTH OF THE SAVANNAH RIVER. SUNDAY...THE INLAND WEDGE WILL BE STRONG...YET RATHER TRANSIENT...AS THE CENTER OF HIGH PRESSURE TO THE NORTH SWIFTLY MOVES OFF THE NEW ENGLAND COASTLINE. A COASTAL TROUGH WILL SHIFT TOWARD THE COAST...THEN PULL NORTHWARD AND DAMPEN OVERNIGHT...AS A WARM FRONTAL FEATURES LIFTS THROUGH THE FORECAST AREA BY MONDAY MORNING. PERSISTENT ISENTROPIC ASCENT ACROSS INLAND AREAS WHERE THE WEDGE REMAINS BEST DEFINED WILL SUPPORT 30 TO 40 PERCENT RAIN CHANCES DURING THE DAYTIME HOURS...DIMINISHING TO THE 20 PERCENT RANGE SUNDAY NIGHT. AS EXPECTED WITHIN A WEDGE TYPE PATTERN AND LINGERING FRONT TO THE SOUTH...A SIGNIFICANT HIGH TEMPERATURE GRADIENT WILL DEVELOP WITH HIGHS RANGING FROM ONLY THE MID/UPPER 50S NORTH TO NEAR 70 DEGREES SOUTH OF INTERSTATE 16 IN SOUTHEAST GEORGIA. LINGERING THICK CLOUD COVER WILL KEEP LOW TEMPERATURES ABOVE SEASONAL NORMALS...IN THE UPPER 40S NORTHWEST ZONES TO THE UPPER 50S/AROUND 60 FAR SOUTHEAST. MONDAY...DEEP SOUTHERLY FLOW WILL QUICKLY SET UP ACROSS THE SOUTHEAST STATES DOWNSTREAM OF ANOTHER COLD FRONT RAPIDLY DEVELOPING ACROSS THE TENNESSEE VALLEY/UPSTATE REGION LATE IN THE DAY. TEMPERATURES WILL REBOUND SIGNIFICANTLY AND PEAK WELL ABOVE SEASONAL NORMALS IN THE MID TO UPPER 70S WITHIN STRONG WARM ADVECTION. WILL CONTINUE TO ADVERTISE INCREASING RAIN CHANCES FROM WEST TO EAST TO ACCOUNT FOR THE APPROACHING COLD FRONT. HOWEVER...LATEST MODEL SOLUTIONS HAVE BEEN TRENDING A BIT DRIER FOR THE DAYTIME HOURS ON MONDAY WITH THE FRONT STILL WELL INLAND...AND SUBSEQUENT FORECASTS MAY CONSIDER ADJUSTING POPS DOWNWARD IF NECESSARY. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... SHORTWAVE ENERGY APPROACHING FROM THE WEST MONDAY NIGHT INTO TUESDAY WILL BE ON A WEAKENING TREND...YET STILL PROVIDE SUFFICIENT ENERGY TO ASSIST THE COLD FRONT THROUGH THE FORECAST AREA AND OFF THE COAST BY TUESDAY EVENING. DRY HIGH PRESSURE WILL BUILD FROM THE WEST IN THE WAKE OF THE FRONT THROUGH THE MID WEEK PERIOD...EVENTUALLY SETTLING DIRECTLY OVER THE MID ATLANTIC AND SOUTHEAST STATES BY LATE NEXT WEEK. HIGHEST RAIN CHANCES WILL BE DURING THE DAYTIME HOURS ON TUESDAY WITH THE FRONTAL PASSAGE...THEN EXPECT LOWERING RAIN POTENTIAL FOR THE REMAINDER OF THE PERIOD. ENHANCED CONVERGENCE ON THE SOUTHERN EXTENT OF THE SURFACE HIGH...ESPECIALLY WHERE A COASTAL TROUGH COULD DEVELOP BY THURSDAY OR FRIDAY...WILL SUPPORT ISOLATED MARINE SHOWER ACTIVITY POSSIBLY MOVING ONSHORE LATE NEXT WEEK. TEMPERATURES WILL PEAK IN THE MID TO UPPER 60S TUESDAY AS THE FRONT CROSSES THE FORECAST AREA...THEN EXPECT HIGH AND LOW TEMPERATURES TO GENERALLY REMAIN BELOW SEASONAL NORMALS MID TO LATE WEEK WITHIN COLD ADVECTION AND PERSISTENT NORTHERLY FLOW. && .AVIATION /07Z FRIDAY THROUGH TUESDAY/... THE FOG FORECAST REMAINS QUITE CHALLENGING AND CARRIES A LOW FORECASTER CONFIDENCE. HIGH CLOUDS AND HIGH WINDS ATOP THE BOUNDARY LAYER WILL LIKELY KEEP THE FOG FAIRLY PATCHY AT KCHS EXCEPT POSSIBLY 10-12Z WHERE CONDITIONS WILL BE THE MOST FAVORABLE FOR FOG FORMATION. WILL CARRY LOW-END MVFR VSBYS FOR NOW WITH VFR CIGS. AT KSAV...CONDITIONS WILL FAVOR MORE FOG WITH THINNER CLOUD COVER AND SLIGHTLY LOWER WIND SPEEDS. WILL BACK OFF A BIT FROM THE 00Z TAF PERIOD OF VSBYS GIVEN THE LATEST SHORT TERM GUIDANCE AND SHOW PREVAILING MVFR VSBYS BY 09Z WITH IFR VSBYS BY 10Z WITH TEMPO CIGS TO AIRFIELD MINIMUMS. THE FOG SHOULD LIFT QUICKLY AFTER SUNRISE WITH VFR CONDITIONS PREVAILING AT BOTH TERMINALS SHORTLY THEREAFTER. EXTENDED AVIATION OUTLOOK...MVFR OR LOWER CIGS/VSBYS ARE POSSIBLE TONIGHT THROUGH SUNDAY NIGHT...AS A FRONT MOVES THROUGH THE REGION AND STALLS OFFSHORE. MVFR CIGS/VSBYS WILL ALSO BE POSSIBLE MONDAY NIGHT INTO TUESDAY WITH ANOTHER COLD FRONT THAT SWEEPS THROUGH THE SOUTHEASTERN UNITED STATES. && .MARINE... TODAY...SEA FOG WILL REMAIN A CONCERN TODAY WITH ELEVATED DEWPOINTS INTERACTING WITH THE COLD SHELF WATERS. THE CHARLESTON PILOT BOAT REPORTED PATCHY DENSE SEA FOG EARLIER THIS MORNING AND SATELLITE DATA SUGGEST THE FOG COULD BE EXPANDING SOUTH. THIS IS HARD TO VERIFY HOWEVER. WILL CONTINUE TO FORECAST PATCHY FOG FOR MUCH OF THE DAY WITH VSBYS 1 NM OR LESS. A MARINE DENSE FOG ADVISORY CAN NOT BE COMPLETELY RULED OUT. OTHERWISE...WINDS WILL BE SOUTH 10-15 KT WITH SEAS 2-4 FT. TONIGHT...WINDS WILL PICKUP A BIT OVERNIGHT AS A COLD FRONT APPROACHES AND LOW-LEVEL JETTING INCREASES. THERE WILL BE A CONTINUED RISK FOR PATCHY SEA FOG...ALTHOUGH THE INCREASING WINDS WILL LIKELY DISPERSE ANYTHING THAT FORMS. WINDS WILL INCREASE TO AROUND 15 KT WITH SEAS 2-4 FT. SATURDAY THROUGH WEDNESDAY...A BACKDOOR COLD FRONT WILL MOVE THROUGH THE MARINE ZONES LATE SATURDAY...SUPPORTING STRENGTHENING NORTHEAST FLOW IN ITS WAKE SATURDAY NIGHT AND SUNDAY. BRIEF SMALL CRAFT ADVISORY CONDITIONS ARE POSSIBLE...PRIMARILY ACROSS THE SOUTH CAROLINA WATERS SATURDAY NIGHT. THE STALLED FRONT SHOULD THEN LIFT NORTH AS A WARM FRONT SUNDAY NIGHT INTO MONDAY...AHEAD OF ANOTHER COLD FRONT PUSHING OVER THE WATERS LATE MONDAY INTO TUESDAY. CONDITIONS COULD ONCE AGAIN APPROACH SMALL CRAFT ADVISORY LEVELS LATE TUESDAY...AS COLD ADVECTION OCCURS BEHIND THE DEPARTING COLD FRONT. && .CLIMATE... RECORD HIGHS FOR TODAY 12/06... KCHS... 81/1998 KSAV... 80/1998 KCHL... 80/1998 RECORD HIGH MINIMUMS FOR TODAY 12/06... KCHS... 62/1972 KSAV... 65/1912 KCHL... 66/1998 RECORD HIGH MINIMUMS FOR SAT 12/07... KCHS... 61/1971 KSAV... 67/1971 KCHL... 66/1998 ALL TIME RECORD HIGHS FOR DECEMBER... KCHS... 83/1972 KSAV... 83/1967 AND 1971 KCHL... 81 NUMEROUS YEARS && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ ST/WMS  FXUS62 KCHS 111220 AFDCHS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 720 AM EST SAT JAN 11 2014 ...SEVERE THUNDERSTORMS POSSIBLE THIS AFTERNOON AND EVENING... .SYNOPSIS... A STRONG COLD FRONT WILL SWEEP ACROSS THE REGION THIS EVENING. HIGH PRESSURE WILL BUILD SUNDAY AND QUICKLY MOVE OFF THE COAST MONDAY...BEFORE ANOTHER COLD FRONT MOVES THROUGH THE AREA BY TUESDAY MORNING. HIGH PRESSURE WILL REBUILD DURING THE MIDDLE OF NEXT WEEK...WITH YET ANOTHER COLD FRONT APPROACHING BY FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AN ACTIVE DAY IS ON TAP FOR SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA AS A COLD FRONT APPROACHES FROM THE WEST. AHEAD OF THE FRONT...INCREASING WARM AIR ADVECTION BEING DRIVEN BY A STRONG PRE-FRONTAL LOW-LEVEL JET WILL HELP PUSH TEMPERATURES INTO THE LOWER-MID 70S FOR MOST AREAS AWAY FROM THE COAST... WHICH IS ABOUT 10-15 DEGREES ABOVE NORMAL. AS WARM AIR ADVECTION INTENSIFIES...ISOLATED TO SCATTERED SHOWERS WILL LIKELY BREAKOUT AND AFFECT PORTIONS OF THE AREA PRIOR TO THE ARRIVAL OF THE MAIN CONVECTIVE LINE. ATTM IT APPEARS THE MAIN CONVECTIVE LINE... POSSIBLY IN THE FORM OF A STRONG/SEVERE QUASI-LINEAR CONVECTIVE SYSTEM /QLCS/...WILL REACH THE FAR WESTERN ZONES BY EARLY AFTERNOON AND REACH THE COAST BY LATE AFTERNOON OR EARLY THIS EVENING. H3R INSTABILITY PROGS AND NAM/RAP MODIFIED POINT SOUNDINGS SUGGEST SBCAPE VALUES WILL RISE TO 900-1200 J/KG WITH LIFTED INDICES DROPPING AS LOW AS -4 TO -6C. ALTHOUGH MID-LEVEL LAPSE RATES WILL BE POOR...HEALTHY 0-6KM BULK SHEAR OF 50-60 KT INDUCED BY STRONG LOW-LEVEL JETTING COUPLED WITH MODEST INSTABILITY WILL SUPPORT A RISK FOR SEVERE TSTMS WITHIN A TYPICAL MID-JANUARY HIGH SHEAR/LOW CAPE ENVIRONMENT. THE PRIMARY HAZARD RIGHT NOW LOOK TO BE DAMAGING WINDS WITH A RISK FOR ISOLATED TORNADOES WHERE DISCRETE CELLS OR EMBEDDED MESO-VORTICES WITHIN BOWING CONVECTIVE LINE SEGMENTS CAN DEVELOP. RAP 0-1KM HELICITY VALUES INCREASE TO NEAR 300 M2/S2 AND THE HIGH SHEAR/LOW CAPE SHERBS3 TORNADO PARAMETER RISES ABOVE THE BENCH MARK OF 1 UNIT FOR MUCH OF THE AREA...ALL SUGGESTING THERE IS A REASONABLE RISK FOR TORNADOES. FOR TODAY...WILL HIGHLIGHT POPS NEAR 100 PERCENT FOR ALL AREAS WITH THE HIGHEST GRIDDED POPS PLACED WITH THE EXPECTED TIMING/PLACEMENT OF THE EXPECTED CONVECTIVE LINE. HIGHS WILL BE IN THE LOWER TO MID 70S UNDER MAINLY CLOUDY SKIES. WILL INCLUDE DAMAGING WIND AND TORNADO ATTRIBUTES IN ALL GRIDDED AND TEXT PRODUCTS AND HIGHLIGHT A POTENTIAL FOR SEVERE TSTMS IN THE HAZARDOUS WEATHER OUTLOOK. THE WINDOW OF GREATEST SEVERE THREAT LOOKS TO BE 1 PM THROUGH 7 PM. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/... TONIGHT...CONDITIONS WILL RAPIDLY IMPROVE THIS EVENING AS THE PRIMARY CONVECTIVE LINE PUSHES OFFSHORE AND THE COLD FRONT MOVES THROUGH. EXPECT CLEARING TO OCCUR DURING THE EVENING HOURS WITH MAINLY CLEAR SKIES DEVELOPING BY MIDNIGHT...IF NOT SOONER. LOWS WILL RANGE FROM THE LOWER 40S WELL INLAND TO THE UPPER 40S AT THE BEACHES. SUNDAY...DRY HIGH PRESSURE WILL BUILD IN THE WAKE OF THE DEPARTING COLD FRONT...YET PROGRESSIVE FLOW ALOFT WILL PULL THE CENTER OF THE HIGH QUICKLY TOWARD THE NEARBY ATLANTIC WATERS. COLD ADVECTION WILL BE WEAK BEHIND THE FRONT...AND WITH WIND DIRECTIONS REMAINING GENERALLY WEST/SOUTHWEST...EXPECT ONLY A SLIGHT COOLING TREND TO OCCUR. HIGH TEMPERATURES IN THE MID TO UPPER 60S WILL BE COOLER THAN THE PREVIOUS DAY...YET STILL BE WELL ABOVE SEASONAL NORMALS. AN AMPLIFYING LONG WAVE TROUGH ACROSS THE CENTRAL PLAINS AFTER MIDNIGHT WILL SUPPORT BRIEF DOWNSTREAM HEIGHT RISES...AND WHEN COMBINED WITH WARM ADVECTION WITHIN BACKING LOW LEVEL FLOW...LOW TEMPERATURES IN THE UPPER 30S INLAND TO LOW 40S NEAR THE COAST WILL ALSO BE SEVERAL DEGREES WARMER THAN AVERAGE. MONDAY...SOUTHERN STREAM SHORTWAVE ENERGY TRACKING ACROSS THE GULF OF MEXICO WILL SPIN UP A SURFACE WAVE ALONG THE WESTERN PERIPHERY OF THE RETREATING ATLANTIC HIGH PRESSURE. THERE REMAINS NOTABLE DISAGREEMENT BETWEEN MODEL SOLUTIONS REGARDING THE STRENGTH AND TRACK OF THIS LOW PRESSURE WAVE AND TRAILING FRONT AS THEY PROGRESS TOWARD THE FORECAST AREA THROUGH THE DAY. IN GENERAL...A SOLID TAP INTO GULF MOISTURE WILL SUPPORT A SWATH OF PRECIPITATION ASSOCIATED WITH THE SYSTEM...AND EXPECT RAIN CHANCES TO INCREASE FROM SOUTHWEST TO NORTHEAST DURING THE LATE AFTERNOON TO EVENING TIME FRAME. WARM ADVECTION AND PRE-FRONTAL COMPRESSION WILL SUPPORT TEMPERATURES PEAKING IN THE MID TO UPPER 60S...EVEN AS CLOUD COVER GRADUALLY INCREASES. THE BEST RAIN POTENTIAL ACTUALLY APPEARS TO OCCUR OVERNIGHT INTO EARLY TUESDAY MORNING..AS THE SURFACE LOW LIFTS NORTH/NORTHEAST AND PULLS THE FRONT INTO THE REGION. LOW TEMPERATURES WILL BE QUITE MILD AS A RESULT...ONLY FALLING INTO THE UPPER 40S TO AROUND 50 DEGREES. TUESDAY...THE SYNOPTIC PATTERN REMAINS A BIT UNSETTLED EVEN AFTER THE FRONT MOVES OFFSHORE...WITH ANOTHER LARGE AREA OF UPPER LEVEL ENERGY SWEEPING SOUTHEAST FROM THE GREAT LAKES REGION. RAIN CHANCES WILL DECREASE DURING THE MORNING HOURS BEHIND THE DEPARTING COLD FRONT. HOWEVER DRY SURFACE HIGH PRESSURE IN ITS WAKE WILL BECOME SUPPRESSED TO THE SOUTH...AS YET ANOTHER FRONT DRIVEN BY THE AMPLIFYING UPPER SHORTWAVE DESCENDS FROM THE OHIO VALLEY LATE IN THE DAY. ONCE AGAIN...DOWNSLOPE FLOW AND THE LACK OF SOLID COLD ADVECTION WILL SUPPORT ABOVE NORMAL HIGH TEMPERATURES IN THE MID 60S. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... THE DEEPENING UPPER TROUGH WILL SHIFT OVER THE EAST COAST STATES ON WEDNESDAY...WITH A DRY COLD FRONT MOVING ACROSS THE REGION EARLY IN THE DAY. THERE APPEARS TO BE MORE NOTABLE COLD ADVECTION BEHIND THIS FRONT...AND EXPECT HIGH TEMPERATURES TO BE SUPPRESSED IN THE MID 50S UNDER MOSTLY CLEAR SKIES ON WEDNESDAY. LOW TEMPERATURES WEDNESDAY NIGHT WILL BE THE COLDEST SEEN IN DAYS...AS LIGHT WINDS AND LITTLE TO NO CLOUD COVER SET UP IDEAL RADIATIONAL COOLING CONDITIONS. A NEARLY ZONAL UPPER PATTERN ON THURSDAY WILL BE RATHER TRANSIENT...AS BROAD TROUGHING BECOMES THE DOMINANT FEATURE ALOFT FRIDAY AND SATURDAY. CONSIDERING DRY SURFACE HIGH PRESSURE WILL ALSO SETTLE OVER THE REGION...EXPECT TEMPERATURES TO BE GENERALLY BELOW NORMAL AND RAIN CHANCES TO REMAIN BELOW 15 PERCENT THROUGH THE EXTENDED FORECAST PERIOD. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... FOG IS IN THE PROCESS OF LIFTING INTO VERY LOW STRATUS DECKS AT BOTH TERMINALS AS BOUNDARY LAYER WINDS INCREASE. LIFR CIGS WILL LINGER THROUGH ABOUT 14Z BEFORE SLOWLY RISING. UNTIL THEN...CIGS WILL REMAIN VERY NEAR AIRFIELD MINIMUMS AND WELL BELOW ALTERNATE MINIMUMS. VFR SHOULD RETURN BY LATE MORNING. SQUALL LINE WILL AFFECT THE TERMINALS THIS AFTERNOON...ROUGHLY FROM 20-23Z. WILL INCLUDE LOW-END MVFR CONDITIONS IN TSRA FOR NOW...BUT BRIEF STINTS AS LOW AS LIFR WILL BE POSSIBLE IN HEAVIER POCKETS OF RAIN. THE FRONT WILL CLEAR THE TERMINALS THIS EVENING...ROUGHLY 00-23Z WITH VFR CONDITIONS RETURNING THROUGH THE NIGHT AS CLEARING TAKES HOLD. EXTENDED AVIATION OUTLOOK...THERE IS A CHANCE OF SHOWERS/MVFR CONDITIONS LATE MONDAY INTO EARLY TUESDAY DUE TO ANOTHER FRONTAL SYSTEM. && .MARINE... SATELLITE AND GOES LIFR PROBABILITIES SUGGEST SEA FOG HAS MOVED INTO THE GEORGIA OFFSHORE WATERS. HAVE EXPANDED THE MARINE DENSE FOG ADVISORY TO INCLUDE THIS AREA THROUGH 10 PM. TODAY...THE RISK FOR WIDESPREAD DENSE SEA FOG WILL LINGER THROUGH MUCH OF THE MORNING HOURS AND MAY PERSIST INTO THE AFTERNOON HOURS AS WARM/MOIST AIR FLOWS OVER THE COLD SHELF WATERS. A MARINE DENSE FOG ADVISORY WILL REMAIN IN FORCE UNTIL 10 AM FOR ALL FORECAST ZONES...BUT MAY NEED TO BE EXTENDED INTO THE AFTERNOON HOURS DEPENDING ON TRENDS AND PILOT BOAT REPORTS LATER THIS MORNING. OTHERWISE...SOUTH WINDS WILL INCREASE TODAY AS A COLD FRONT DRAWS CLOSER. EXPECT WINDS TO INCREASE TO 15-20 KT NEARSHORE WATERS AND 20-25 KT OFFSHORE WATERS. SEAS WILL BUILD AS A RESULT...RISING TO 4-7 FT NEARSHORE WATERS AND 6-8 FT OFFSHORE WATERS. A LINE OF STRONG TO SEVERE TSTMS WILL LIKELY APPROACH THE LOCAL MARINE AREA LATE IN THE AFTERNOON...ALTHOUGH A FEW STRONG SHOWERS/TSTMS MAY POP OVER THE COASTAL WATERS PRIOR TO ARRIVAL OF THE PRIMARY CONVECTIVE LINE. SPECIAL MARINE WARNINGS MAY BE NEEDED. TONIGHT...THE SQUALL LINE WILL PUSH ACROSS THE WATERS THIS EVENING AND BE FOLLOWED BY THE COLD FRONT. WINDS WILL QUICKLY SHIFT WEST WITH THE FRONT AND INCREASE WITH THE ONSET OF COLD AIR ADVECTION. WINDS LOOK TO PEAK 20-25 KT NEARSHORE WATERS AND 25-30 KT OFFSHORE WATERS. RIGHT NOW WINDS LOOK TO REMAIN BELOW GALE FORCE...ALTHOUGH A BRIEF STINT OF 35 KT WINDS WILL BE POSSIBLE. WILL MAINTAIN SMALL CRAFT ADVISORIES FOR ALL WATERS...EXCLUDING THE CHARLESTON HARBOR. OFFSHORE WINDS WILL HAVE A DECAYING EFFECT OF SEAS OVER THE NEARSHORE WATERS WITH SEAS SUBSIDING BY ABOUT 1-2 FT...BUT SEAS OF 6-8 FT WILL LINGER OVER THE OFFSHORE WATERS WHERE THE FETCH WILL BE CONSIDERABLY LONGER. SUNDAY THROUGH WEDNESDAY...LINGERING SMALL CRAFT ADVISORIES WILL BE ABLE TO END BY SUNDAY MORNING/EARLY AFTERNOON...AS SURFACE HIGH PRESSURE RAPIDLY BUILDS OVER THE REGION IN THE WAKE OF THE COLD FRONT. MARINE CONDITIONS WILL THEN REMAIN RATHER QUIET THROUGH THE DAYTIME HOURS ON MONDAY. A WAVE OF LOW PRESSURE IN THE GULF OF MEXICO WILL LIFT TOWARD THE SOUTHEAST STATES LATE MONDAY...LIKELY PULLING A COLD FRONT OFF THE COAST BY TUESDAY MORNING. EXPECT A SURGE IN SOUTHERLY WINDS AHEAD OF THE SYSTEM EARLY TUESDAY...WITH THE POTENTIAL FOR ONLY MARGINAL ADVISORY-LEVEL WINDS ACROSS PORTIONS OF THE WATERS. A MORE SOLID SURGE INTO SMALL CRAFT ADVISORY CONDITIONS WILL OCCUR WITHIN COLD ADVECTION AND WESTERLY FLOW BEHIND A SECONDARY COLD FRONT MOVING THROUGH THE AREA EARLY WEDNESDAY. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR GAZ117-119- 139-141. SC...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR SCZ048>052. MARINE...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR AMZ330-350- 352-354-374. SMALL CRAFT ADVISORY UNTIL 5 AM EST SUNDAY FOR AMZ352-354. SMALL CRAFT ADVISORY UNTIL 8 AM EST SUNDAY FOR AMZ350. SMALL CRAFT ADVISORY UNTIL 1 PM EST SUNDAY FOR AMZ374. && $$ ST/WMS  FXUS62 KCHS 060229 AFDCHS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 929 PM EST WED FEB 5 2014 .SYNOPSIS... A COLD FRONT WILL MOVE OFFSHORE EARLY THIS EVENING. HIGH PRESSURE WILL THEN BUILD IN FROM THE NORTH AND WEST TONIGHT INTO FRIDAY BEFORE UNSETTLED WEATHER RETURNS THIS WEEKEND AS AN AREA OF LOW PRESSURE PASSES OFFSHORE. HIGH PRESSURE WILL RETURN TO THE REGION EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... THE COLD FRONT HAS CLEARED THE COAST WITH A DRIER AIRMASS ADVECTING IN BEHIND IT. WINDS WILL PICK UP SOME OVER THE NEXT FEW HOURS AS THE PRESSURE GRADIENT TIGHTENS AND COLD AIR ADVECTION INITIATES. THERMAL FALLS HAVE BEEN SLOWER TO OCCUR THIS EVENING WITH A SLOWER PROGRESSION OF THE COLD FRONT...BUT WILL ACCELERATE WITH THE FRONT NOW OFFSHORE. ADJUSTED HOURLY TEMPERATURES TO BETTER REFLECT EXPECTED THERMAL TRENDS OVER THE NEXT FEW HOURS. ALSO MADE SOME VERY MINOR ADJUSTMENTS OVERNIGHT LOWS...BUT THESE WILL NOT MAKE ANY BIG DIFFERENCES IN THE TEXT BASED PRODUCTS. LOWS WILL RANGE FROM THE MID 30S INLAND TO THE UPPER 30S/LOWER 40S COAST. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/... THURSDAY AND THURSDAY NIGHT...THE FORECAST AREA WILL REMAIN ON THE SOUTHEASTERN PERIPHERY OF AN EXTENSIVE SURFACE HIGH PRESSURE SYSTEM THAT EXTENDS INTO WESTERN CANADA. MODEL SOUNDINGS SHOW PLENTY OF DRY AIR IN PLACE THURSDAY MORNING WITH PWATS BELOW HALF AN INCH. THEREFORE...EXPECT PLENTY OF SUNSHINE INITIALLY ON THURSDAY WITH NO MORE THAN SCATTERED JET INDUCED CIRRUS. MOISTURE PROFILES WILL SLOWLY INCREASE THROUGH THURSDAY NIGHT. THE LATEST MODEL RUNS ARE FAIRLY CONSISTENT IN SHOWING SHOWER POTENTIAL DURING THE OVERNIGHT HOURS DUE TO A COMBINATION OF SHOWERS ASSOCIATED WITH A WEAK SHORTWAVE TRACKING ACROSS CENTRAL GEORGIA AND BUILDING MOISTURE OVER THE WESTERN ATLANTIC. HAVE INCREASED POPS SLIGHTLY LATE THURSDAY NIGHT...BUT DUE TO SOME INCONSISTENCIES WITH PREVIOUS MODEL RUNS...WILL REMAIN CONSERVATIVE FOR NOW AND KEEP POPS CAPPED AT 20 PERCENT. IN REGARD TO TEMPERATURES...HIGHS ARE ONLY EXPECTED TO CLIMB INTO THE MID 50S TO RIGHT AROUND 60 DEGREES CLOSE TO THE ALTAMAHA...DESPITE SUNSHINE. LOW TEMPERATURES WILL DIP INTO THE UPPER 30S/MID 40S CLOSER TO THE COAST. FRIDAY THROUGH SATURDAY...THE WEAK SHORTWAVE WILL HAVE PASSED OFFSHORE BY FRIDAY AS THE CENTER OF THE HIGH PRESSURE SYSTEM SHIFTS EASTWARD TOWARD THE MID ATLANTIC STATES. WITH MOISTURE PROFILES DIMINISHING ON FRIDAY...EXPECT MOST AREAS TO REMAIN DRY THROUGH THE DAY. A FEW SHOWERS COULD BRUSH COASTAL AREAS AS A WEAK TROUGH DEVELOPS OFFSHORE. HOWEVER...THE BEST SHOT FOR RAIN WILL BE LATE FRIDAY NIGHT AND INTO SATURDAY AS HEIGHTS BEGIN TO FALL DUE TO AN APPROACHING SHORTWAVE AND A DEVELOPING COASTAL LOW OFF THE SOUTHEAST. THE COMBINATION OF THESE SYSTEMS AND THE POSITION OF THE UPPER JET SHOULD SUPPLY ENOUGH FORCING FOR DECENT RAIN COVERAGE. HAVE MAINTAINED PREVIOUS THINKING WITH HIGHEST POPS ON SATURDAY. TEMPERATURES WILL REMAIN SIMILAR ON FRIDAY AND SATURDAY WITH HIGHS RANGING BETWEEN THE LOWER 50S ACROSS NORTHERN PORTIONS OF THE LOWCOUNTRY TO UPPER 50S SOUTH OF INTERSTATE 16. FRIDAY NIGHT LOWS WILL ONLY DIP INTO THE LOWER 40S/NEAR 50 DEGREES CLOSE TO THE COAST. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... OVERALL CONFIDENCE IN THE LONG TERM FORECAST PERIOD HAS IMPROVED THANKS TO BETTER MODEL AGREEMENT. THE AREA OF LOW PRESSURE IS EXPECTED TO PULL WELL AWAY FROM THE COAST AS ANOTHER LARGE AREA OF HIGH PRESSURE BUILDS INTO THE REGION THROUGH EARLY IN THE WEEK. WE HAVE SOME LINGERING LOW END POPS SATURDAY NIGHT ON THE BACK SIDE OF THE DEPARTING LOW...AND THEN THINGS DRY OUT STARTING ON SUNDAY. RAIN CHANCES DON/T CREEP BACK INTO THE FORECAST UNTIL TUESDAY AS THE SURFACE HIGH SETTLES INTO A GOOD DAMMING POSITION AND A COASTAL TROUGH DEVELOPS ALONG THE COAST. LOW END POPS WILL SUFFICE TUESDAY AND TUESDAY NIGHT...BEFORE MORE SIGNIFICANT CHANCES START ON WEDNESDAY. ANOTHER SOUTHERN STREAM SHORTWAVE WILL APPROACH FROM MID WEEK ONWARD...AND IT APPEARS AN ORGANIZED AREA OF LOW PRESSURE WILL IMPACT THE REGION. UNDER THE INFLUENCE OF COOL NORTH TO NORTHEAST FLOW THANKS TO THE SURFACE HIGH...TEMPS WILL RUN BELOW NORMAL THROUGH THE ENTIRE LONG TERM PERIOD. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... VFR. EXTENDED AVIATION OUTLOOK...CHANCES FOR FLIGHT RESTRICTIONS INCREASE FRIDAY NIGHT AND INTO SATURDAY AS AN AREA OF LOW PRESSURE PASSES OFFSHORE. && .MARINE... TONIGHT...GOES-EAST SATELLITE DERIVED IFR PROBABILITY DATA INDICATE THE WESTERN FLANKS OF THE DENSE SEA FOG BANK WILL CLEAR THE CHARLESTON COUNTY MARINE ZONE JUST BEFORE 11 PM. EXTENDED THE MARINE DENSE FOG ADVISORY FOR AN HOUR GIVEN THIS. THE WORST VISIBILITIES WILL BE FOUND 10-20 NM OFFSHORE WITH CONDITIONS IMPROVING FROM WEST-EAST THROUGH 11 PM. OTHERWISE...WINDS WILL INCREASE OVERNIGHT AS AS SECONDARY WIND SURGE WORKS DOWN THE COAST. ATTM IT APPEARS BOTH WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS. THURSDAY THROUGH SUNDAY...HIGH PRESSURE WILL BUILD ACROSS THE REGION THURSDAY AND FRIDAY...BUT A DEVELOPING TROUGH COULD LEAD TO SOME SCATTERED SHOWERS ACROSS THE COASTAL WATERS PERIODICALLY THROUGH THE PERIOD. EXPECT THURSDAY TO INITIALIZE WITH SUB-SCA CONDITIONS...BUT WINDS COULD STILL REMAIN ELEVATED BETWEEN 15 TO 20 KNOTS AT TIMES THROUGH FRIDAY. IN FACT...THERE IS A CHANCE WINDS COULD INCREASE BRIEFLY TO SCA CONDITIONS THURSDAY NIGHT ACROSS THE OUTER GEORGIA WATERS. FRIDAY NIGHT/EARLY SATURDAY...AN AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP OFF THE SOUTHEAST COAST...POSSIBLY WARRANTING SCA HEADLINES. THE LOW IS EXPECTED TO QUICKLY PULL AWAY TO THE NORTHEAST SATURDAY NIGHT. WINDS WILL THEN BECOME NORTHWEST AS HIGH PRESSURE RETURNS. THE GRADIENT AND COLD ADVECTION WILL INCREASE DURING THE DAY ON SUNDAY. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...DENSE FOG ADVISORY UNTIL 11 PM EST THIS EVENING FOR AMZ350. && $$ ST  FXUS62 KCHS 010632 AFDCHS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 132 AM EST SAT MAR 1 2014 .SYNOPSIS... A COASTAL TROUGH WILL REMAIN JUST OFFSHORE TONIGHT AS A WEDGE OF HIGH PRESSURE PUSHES SOUTHWARD INTO THE AREA...AND PERSISTS THROUGH LATE SATURDAY. ATLANTIC HIGH PRESSURE WILL BECOME ESTABLISHED LATER THIS WEEKEND AHEAD OF A COLD FRONT MOVING THROUGH BY MONDAY NIGHT. HIGH PRESSURE WILL BUILD AGAIN NORTH OF THE REGION INTO THE MIDDLE OF NEXT WEEK. A DEVELOPING STORM SYSTEM COULD AFFECT THE AREA WITH WIDESPREAD RAINFALL BY LATE IN THE WORK WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... A MID-TROPOSPHERIC SHORT WAVE IS SHOWN ON WATER VAPOR TREKKING EAST FAIRLY QUICKLY THROUGH EASTERN ALABAMA. AT THE SURFACE...A CHILLY HIGH PRESSURE WEDGE IS ANCHORED IN PLACE WHILE NOT FAR OFFSHORE WE FIND AN INVERTED TROUGH OUT NEAR THE GULF STREAM. WHILE THE SHORT WAVE DOES ARRIVE VERY LATE TONIGHT...THERE IS LITTLE FLUCTUATION IN THE OVERALL SURFACE SYNOPTIC PATTERN THROUGH THE NIGHT. THIS UPSTREAM IMPULSE WILL COMBINE WITH INCREASING ISENTROPIC ASCENT ON THE 290K SURFACE TO PERHAPS GENERATE A FEW LOW-TOPPED SHOWERS VERY LATE TONIGHT ACROSS NORTHERN CHARLESTON AND FAR EASTERN BERKELEY COUNTY. BUT GIVEN THAT THE SYNOPTIC FLOW IS PARALLEL TO THE COAST WE HAVE KEPT ANY MEASURABLE RAINS OVER THE ATLANTIC. CLOUD COVER WILL CONTINUE TO EXPAND AND LOWER THROUGH THE NIGHT...WITH THE BULK OF THE AVAILABLE MOISTURE TRAPPED BENEATH BOTH THE WEDGE AND NOCTURNAL INVERSIONS. THESE INCREASING STRATOCUMULUS AND STRATUS CLOUDS FROM OFF THE ATLANTIC ALONG WITH HIGHER JET STREAM CLOUDS ARRIVING FROM THE WEST WILL SUPPORT SKIES TURNING OUT TO BE CLOUDY. IF THE STRATUS BUILDS LOW ENOUGH IT COULD LEAD TO THE DEVELOPMENT OF SOME FOG. FOR NOW WE HAVE REFRAINED FROM ADDING TO THE FORECAST UNTIL WE CAN BE CERTAIN ON HOW LOW CEILINGS WILL GET. TEMPS WON/T BE AS COLD AS LAST NIGHT...BUT WITH A CONTINUED INFLUX OF AIR FROM THE NORTH AND NE IT WILL LEAD TO LOWS WITHIN A FEW DEGREES EITHER SIDE OF 40 INLAND AND THE MID 40S ON THE COASTAL COMMUNITIES. && .SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/... SATURDAY...THE AREA WILL REMAIN SITUATED BETWEEN A WEDGE OF HIGH PRESSURE OVER LAND AND A COASTAL TROUGH OFF THE SOUTHEAST COAST. PRECIP CHANCES WILL REMAIN QUITE LOW OVER THE COURSE OF THE DAY...BUT WE COULD SEE A FEW SHOWERS NORTH OF INTERSTATE 26 IN CHARLESTON AND BERKELEY COUNTIES AS FORCING ASSOCIATED WITH A H5 SHORTWAVE AND H25 JET PASS ALOFT. ANY SHOWERS THAT DEVELOP WILL LIKELY SHIFT OFFSHORE SATURDAY AFTERNOON AS MID/UPPER LVL FORCING HEAD OVER THE WESTERN ATLANTIC. THE WEDGE OF HIGH PRESSURE IS THEN EXPECTED TO GRADUALLY WEAKEN OVER THE SOUTHEAST SATURDAY EVENING AND NIGHT WHILE THE PARENT CENTER OF HIGH PRESSURE SLIDES WELL OFF THE NORTHEAST COAST. THE CHANGING PATTERN WILL LIKELY RESULT IN A WARMING TREND LATE AS A MARGINAL DOWNSLOPING WIND COMPONENT DEVELOPS OVER THE SOUTHEASTERN UNITED STATES AND CLOUD COVER DIMINISHES FROM SOUTHWEST TO NORTHEAST. MID LVL RIDGING EXTENDING FROM THE GULF OF MEXICO WILL ALSO CONTRIBUTE TO WARMING SFC TEMPS TO NEAR NORMAL FOR THIS TIME OF YEAR. LATEST 1000-850 MB THICKNESSES FAVOR OVERALL HIGH TEMPS IN THE LOW/MID 60S OVER MOST LOCATIONS...AND A FEW UPPER 60S FOR LOCATIONS SOUTH OF INTERSTATE 16 IN SOUTHEAST GEORGIA. OVERNIGHT LOWS ARE EXPECTED TO RANGE IN THE LOW 40S INLAND TO MID/UPPER 40S NEAR THE COAST. SUNDAY...DRY WEATHER CONDITIONS UNDER MOSTLY SUNNY SKIES ARE EXPECTED TO START OFF THE WEEK AS THE REMNANTS OF THE WEDGE ERODE EARLY BEFORE ATLANTIC HIGH PRESSURE GRADUALLY SLIDES SOUTH ALONG THE THE MID ATLANTIC AND SOUTHEAST COASTS. THE SHIFT IN HIGH PRESSURE WILL ALLOW SFC WINDS TO VEER FROM NORTH/NORTHEAST TO SOUTH/SOUTHEAST SUNDAY AFTERNOON...THUS FAVORING WARMER TEMPS AS WARM AIR ADVECTION OCCURS OVER THE REGION WHILE MID LVL RIDGING EXPANDS FROM THE GULF OF MEXICO. 1000-850 MB THICKNESSES SUGGEST OVERALL HIGH TEMPS IN THE LOW TO MID 70S OVER MOST LOCATIONS...HIGHEST IN SOUTHEAST GEORGIA AWAY FROM THE COAST. DESPITE CLEARING SKIES SUNDAY NIGHT...WARM SOUTHERLY FLOW WILL KEEP OVERNIGHT LOWS IN THE LOW/MID 50S. MONDAY...CHANCES OF SHOWERS WILL INCREASE THROUGHOUT THE DAY AS A H5 SHORTWAVE QUICKLY ADVANCES TOWARD THE SOUTHEASTERN UNITED STATES WHILE SOUTHERLY FLOW WARM TEMPS AND INCREASES MOISTURE AHEAD OF A SFC COLD FRONT APPROACHING FROM THE WEST/NORTHEAST MONDAY EVENING. SEVERAL OF THE MODELS INDICATE THAT THE FRONT WILL WEAKEN AS IT APPROACHES THE AREA WITH LOW AMOUNTS OF QPF. HAVE THEREFORE MAINTAINED ONLY A 20-40 POP SCHEME THROUGHOUT THE DAY WITH GREATEST CHANCES OF PRECIP BEGINNING INLAND EARLY...THEN GRADUALLY MAKING WAY TO THE COAST AS THE FRONT SHIFTS THROUGH THE AREA LATE. WE COULD SEE GUSTY WINDS AHEAD OF THE COLD FRONT MONDAY AFTERNOON AS A 40-50 KT LOW LVL JET PASSES OVER THE AREA WHILE TEMPS PEAK INTO THE MID 70S. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... THE QUICK MOVING COLD FRONT MENTIONED IN THE SHORT TERM PERIOD SHOULD BE WELL EAST OF THE AREA BY MONDAY NIGHT WITH HIGH PRESSURE BUILDING BACK NORTH OF THE REGION TUESDAY. THE SURFACE HIGH PRESSURE HANGS ON AS A WEAK WEDGE WEDNESDAY. THE COOLEST DAY WILL BE WEDNESDAY WITH MORNING LOWS IN THE MID 30S INLAND TO NEAR 40 COAST AND HIGHS IN THE 50S TO NEAR 60. BY WEDNESDAY NIGHT...MODELS BEGIN TO DIVERGE. THE MAIN FEATURE OF CONCERN WILL BE THE DEVELOPING STORM SYSTEM IN THE SOUTHERN STREAM FLOW OVER TEXAS AND THE WESTERN GULF OF MEXICO. THE GFS KEEPS THE UPPER WAVE WITH THIS SYSTEM OPEN/PROGRESSIVE...WITH THE BEST CHANCES FOR WIDESPREAD SHOWERS/RAIN LATE WEDNESDAY NIGHT THROUGH THURSDAY. THE ECMWF TRIES TO CLOSE THE UPPER LOW OFF...RESULTING IN A SLOWER START TO THE PRECIP...ABOUT 6-12 HOURS...AND A MUCH SLOWER ENDING. IN FACT...THE ECMWF STILL HAS A CLOSED UPPER LOW AND PRECIP CHANCES OVER THE REGION FRIDAY. HAVE TRIED TO KEEP CONTINUITY WITH PREVIOUS FORECAST WHILE TRYING TO BLEND/AVERAGE THE LATEST SOLUTIONS. FOR NOW...HAVE LOW END CHANCE POPS LATE WEDNESDAY NIGHT...TO HIGH END CHANCE THURSDAY. TRENDED POPS BACK DOWN BY FRIDAY...BUT KEPT SLIGHT CHANCE GIVEN SLOWER ECMWF SOLUTION. THE LOW LEVELS WILL LIKELY BE DOMINATED BY A WEDGE OF HIGH PRESSURE MUCH OF THE PERIOD...WHICH SHOULD HELP TO KEEP TEMPS COOL/BELOW NORMAL. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... KCHS...CONSIDERABLE MOISTURE TRAPPED BENEATH THE INVERSION WILL RESULT IN SOLID MVFR CEILINGS THROUGH MIDDAY SATURDAY. IMPROVEMENT TO LOW-END VFR CEILINGS IS EXPECTED AFTER 19Z...ALTHOUGH THERE IS A LOW END PROBABILITY THAT MVFR CEILINGS COULD LAST LONGER OR EVEN RETURN SOMETIME AFTER 00Z BUT HAVE KEPT VFR IN THE TAF/S GIVEN THE UNCERTAINTY. KSAV...CONSIDERABLE MOISTURE TRAPPED BENEATH THE INVERSION WILL RESULT IN SOLID MVFR CEILINGS THROUGH MIDDAY SATURDAY. HOWEVER...THE GOES EAST SATELLITE DERIVED IFR PROBABILITY PRODUCT SHOWS EXPANDING IFR CONDITIONS ALONG THE SOUTHEAST GEORGIA COAST AND HAVE ADDED A TEMPO GROUP WITH IFR CEILINGS FROM 08-12Z. IMPROVEMENT TO LOW-END VFR CEILINGS IS EXPECTED AFTER 19Z...ALTHOUGH THERE IS A LOW END PROBABILITY THAT MVFR CEILINGS COULD LAST LONGER OR EVEN RETURN SOMETIME AFTER 00Z BUT HAVE KEPT VFR IN THE TAF/S GIVEN THE UNCERTAINTY. EXTENDED AVIATION OUTLOOK...MVFR OR LOWER CIGS/VSBYS WILL BE POSSIBLE EARLY SUNDAY AS HIGH PRESSURE WEDGES INTO THE AREA. VFR CIGS/VSBYS ARE THEN ANTICIPATED SUNDAY AFTERNOON THROUGH MONDAY MORNING. LOW TO MODERATE CHANCES OF MVFR CIGS/VSBYS ARE POSSIBLE MONDAY AFTERNOON INTO MONDAY NIGHT DUE TO SHOWERS ALONG A PASSING COLD FRONT. CIG/VSBY REDUCTIONS COULD OCCUR WITH AN APPROACHING STORM SYSTEM AS EARLY AS WEDNESDAY NIGHT...BUT CONFIDENCE REMAINS LOW IN THE TIMING OF THE EVENT DUE TO SEVERAL MODEL INCONSISTENCIES. && .MARINE... TONIGHT...A PINCHED PRESSURE PATTERN WILL PERSIST BETWEEN AND INLAND HIGH PRESSURE WEDGE AND A COASTAL TROUGH OVER OR NEAR THE LOCAL WATERS. ON AVERAGE WE/RE LOOKING FOR ABOUT A 2-3 MB SPREAD FROM NORTH TO SOUTH ACROSS THE MARINE AREA. BASED ON LATEST OBSERVATIONS AND THE FACT THAT ANY SLACKENING OF THE GRADIENT WILL BE SLOW...WE HAVE EXTENDED THE END TIME OF THE SCA/S SO THAT ALL EXPIRE AT 7 AM. IN REGARDS TO SPECIFIC WINDS...NE WINDS WILL AVERAGE 20-25 KT NORTH AND 15-20 KT SOUTH EARLY TONIGHT...BUT WITH HIGHER GUSTS...BEFORE THEY DROP ABOUT 5 KT LATE. SEAS HAVE BEEN AS HIGH AS 10 FT AT BUOY 41004 AND 5 FT AT BUOY 41008. IN BETWEEN THEY ARE RUNNING AROUND 6-8 FT. OVERALL SEAS WILL DIMINISH ABOUT A FOOT OR TWO BY DAYBREAK SATURDAY. IN CHARLESTON HARBOR THE NE WINDS WILL PEAK AROUND 15 KT EARLY TONIGHT...DROPPING TO AROUND 10-12 KT LATE. MARINERS ARE ADVISED THAT GIVEN LOWER STRATUS CLOUD DECKS THROUGH THE NIGHT THAT THERE COULD BE SOME REDUCTION IN VISIBILITIES...BUT NO ACTUAL SEA FOG IS ANTICIPATED. SATURDAY THROUGH WEDNESDAY...WINDS/SEAS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY LEVELS LATE WEEKEND INTO EARLY NEXT WEEK AS A WEDGE OF HIGH PRESSURE ERODES INLAND ON SUNDAY AND A COASTAL TROUGH LIFTS NORTH OF THE WATERS BY SUNDAY NIGHT. WINDS/SEAS WILL THEN GRADUALLY INCREASE/BUILD ALONG THE WESTERN EDGE OF ATLANTIC HIGH PRESSURE AS WINDS BECOME SOUTHERLY AHEAD OF A COLD FRONT APPROACHING FROM THE WEST/NORTHWEST LATE MONDAY. WE COULD SEE MARGINAL SMALL CRAFT ADVISORY LEVEL CONDITIONS MONDAY AFTERNOON/EVENING AS STRONG LOW LVL WINDS SHIFT OVER THE WATERS AHEAD/ALONG THE COLD FRONT. THERE WILL ALSO BE A LOW CHANCE OF SEA FOG DEVELOPING ON MONDAY AS SFC DEWPTS APPROACH THE UPPER 50S OVER COOLER NEARSHORE WATERS. THE COLD FRONT WILL MOVE THROUGH THE REGION MONDAY NIGHT WITH MARGINAL SMALL CRAFT ADVISORY LEVEL CONDITIONS BEHIND THE FRONT ON TUESDAY AS THE PRESSURE GRADIENT TRIES TO PINCH BETWEEN A WEDGE OF HIGH PRESSURE INLAND AND LOWER PRESSURE OVER THE ATLANTIC. HIGH PRESSURE WILL HOLD NORTH AND EAST OF THE REGION THROUGH WEDNESDAY BUT WINDS/SEAS ARE EXPECTED TO STAY JUST BELOW SMALL CRAFT ADVISORY LEVELS AT THIS POINT. && .TIDES/COASTAL FLOODING... SATURDAY...ASTRONOMICAL TIDE LEVELS WILL BE ELEVATED COMING OUT OF THE PERIGEE THURSDAY...WITH A NEW MOON ON SATURDAY. A TIGHT SURFACE PRESSURE GRADIENT WILL RESULT IN AN ENHANCED NORTHEAST FLOW DURING SOME OF THIS TIME...AND WHEN COMBINED WITH THE ALREADY ELEVATED ASTRONOMICAL TIDES...COULD RESULT IN SHALLOW COASTAL FLOODING AT THE TIME OF HIGH TIDES TONIGHT AND SATURDAY. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EST THIS MORNING FOR AMZ350- 352-374. && $$ SYNOPSIS... NEAR TERM... SHORT TERM...DPB LONG TERM...RFM AVIATION...JAQ MARINE... TIDES/COASTAL FLOODING...  FXUS62 KCHS 072300 AFDCHS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 700 PM EDT THU MAY 7 2015 .SYNOPSIS... LOW PRESSURE WILL LINGER OFF THE SOUTH CAROLINA COAST TONIGHT THROUGH SATURDAY BEFORE SLOWLY DRIFTING TOWARD THE COAST ON SUNDAY. THE LOW WILL LIFT NORTHEAST THROUGH EASTERN NORTH CAROLINA ON MONDAY. A WEAK COLD FRONT MAY PUSH THROUGH THE REGION BY THE MIDDLE OF NEXT WEEK. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... RECONNAISSANCE AIRCRAFT IS CURRENT APPROACHING STRONG LOW PRESSURE OFF THE SOUTH CAROLINA/GEORGIA COAST. CONVECTION CONTINUES TO DEVELOP AND BECOME MORE CONCENTRATED NEAR THE BROAD LOW-LEVEL CIRCULATION...WHICH SUGGESTS THE LOW IS SLOWLY BECOMING BETTER ORGANIZED. DRY AIR CONTINUES TO ENTRAIN INTO THE SYSTEM FROM THE SOUTH AND SOUTHEAST...BUT DEVELOPING CONVECTION NEAR THE GULF STREAM COULD BE HELPING TO MIX OUT THAT DRY AIR...AT LEAST SOME. WE CONTINUE TO COORDINATE CLOSELY WITH THE NATIONAL HURRICANE CENTER. TROPICAL STORM WATCHES AND/OR WARNINGS MAY VERY WELL BE NEEDED FOR THE COASTAL WATERS AND POSSIBLY PARTS OF THE COAST LATER THIS EVENING OR OVERNIGHT. FOR THE EARLY EVENING UPDATE...A LARGE FEEDER BAND CONTINUES TO DROP SOUTH THROUGH SOUTHEAST GEORGIA EARLY THIS EVENING. THIS BAND WILL DIMINISH AND DROP SOUTH OF THE ALTAMAHA RIVER BY 8 PM OR SO AND EXPECT VERY LITTLE IN THE WAY OF WIDESPREAD ACTIVITY FOR THE NEXT FEW HOURS...OUTSIDE OF ANY LINGERING ISOLATED TO SCATTERED SHOWERS. AS LOW PRESSURE MEANDERS CLOSER...FEEDER BAND ACTIVITY COULD INCREASE ALONG THE LOWER SOUTH CAROLINA COAST LATE TONIGHT...POSSIBLY JUST THE CHARLESTON COUNTY COAST. WINDS WILL ALSO REMAIN QUITE BREEZY ALONG SOUTH COASTAL SOUTH CAROLINA BEACHES WITH WINDS CLOSE TO WIND ADVISORY THRESHOLDS EAST OF HIGHWAY 17 IN CHARLESTON COUNTY. WILL HOLD OFF ON HOISTING ANY ADVISORY AT THIS POINT GIVEN THE RELATIVE SMALL AREA IMPACTED... BUT THIS WILL BE REEVALUATED AS THE EVENING PROGRESSES. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/... THE LATEST GUIDANCE IS IN RELATIVELY GOOD AGREEMENT THAT THE LOW PRESSURE SYSTEM OFF THE SC COAST WILL MOVE VERY LITTLE FRIDAY AND FRIDAY NIGHT BEFORE DRIFTING SLOWLY WEST-NORTHWEST SATURDAY AND SATURDAY NIGHT. THE 12Z ECMWF AND GFS ARE QUITE SIMILAR THOUGH THE ECMWF IS A TAD SLOWER WITH THE SYSTEM APPROACHING THE COASTLINE LATE SATURDAY NIGHT. FOR THE FRIDAY THROUGH SUNDAY PERIOD...THE WEATHER WILL VARY SIGNIFICANTLY BETWEEN SOUTHEAST GEORGIA AND SOUTHERN SOUTH CAROLINA. THE PRIMARY CLOUD SHIELD WILL REMAIN OVER SOUTH CAROLINA WHILE WAVES OF RAIN PUSH INTO OUR FAR EASTERN ZONES FROM OFF THE ATLANTIC. MEANWHILE...PARTLY TO MOSTLY SUNNY SKIES WILL PREVAIL OVER MUCH OF SOUTHEAST GA. TEMPERATURES OVER EASTERN AREAS INCLUDING THE TRI-COUNTY WILL BE LIMITED TO THE MIDDLE 70S ON FRIDAY WHILE SOUTHEAST GEORGIA WARMS INTO THE LOW TO MID 80S. TEMPS WILL GRADUALLY SHIFT UPWARD SATURDAY INTO SUNDAY AS THE LOW WEAKENS AND MORE DRY AIR WRAPS AROUND THE WESTERN FLANKS...ALLOWING FOR MORE INSOLATION. TEMPS WILL SOLIDLY BE IN THE 80S SATURDAY AND SUNDAY. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... THE AFOREMENTIONED SURFACE LOW WILL LIFT WELL AWAY FROM THE FORECAST AREA SUNDAY NIGHT AND MONDAY AND A DEEP MID/UPPER LEVEL RIDGE WILL GRADUALLY BUILD ACROSS THE SOUTHEAST THROUGH THE MIDDLE OF NEXT WEEK AND BEYOND. THE OVERALL TREND IS FOR TEMPERATURES WARMING TO WELL ABOVE NORMAL...INTO THE UPPER 80S BY THE MIDDLE OF THE WEEK...WITH MAINLY ISOLATED TO SCATTERED DIURNAL CONVECTION EACH AFTERNOON AND EVENING. A WEAK COLD FRONT MAY SINK INTO THE AREA LATE IN THE FORECAST PERIOD...BUT IT IS UNCLEAR WHETHER OR NOT THIS FEATURE WILL ACTUALLY CLEAR THE REGION. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... KCHS...VFR FOR MUCH OF THE NIGHT WITH MVFR PROBABILITIES INCREASING AFTER 10Z AS ANOTHER FEEDER BAND APPROACHES FROM LOW PRESSURE OFFSHORE. WILL HIGHLIGHT PREVAILING MVFR CIGS 10-14Z WITH LIGHT RAIN DURING THIS TIME. VFR THEREAFTER...ALTHOUGH THIS IS HIGHLY DEPENDENT ON HOW CONVECTION ON THE WESTERN WALL OF THE LOW PRESSURE DEVELOPS. GUSTY WINDS WILL DIMINISH SOME OVERNIGHT...THEN PICK BACK UP AFTER SUNRISE. KSAV...VFR. SHOWERS NEAR THE TERMINAL WILL CONTINUE TO PUSH SOUTH. GUSTY WINDS WILL DIMINISH THIS EVENING...THEN PICK BACK UP AFTER SUNRISE. EXTENDED AVIATION OUTLOOK...PERIODIC FLIGHT RESTRICTIONS ARE POSSIBLE THROUGH SATURDAY...MAINLY AT KCHS. OTHERWISE VFR CONDITIONS ARE EXPECTED TO PREVAIL. && .MARINE... TONIGHT...LOW PRESSURE OFF THE LOWER SOUTH CAROLINA COAST WILL DRIFT SLOWLY NORTHWEST TONIGHT...POTENTIALLY BECOMING BETTER ORGANIZED AND DEVELOPING INTO A SUBTROPICAL CYCLONE. A TIGHT SURFACE PRESSURE GRADIENT TO THE NORTH AND WEST OF THE LOW HAS RESULTED IN STRONGER GUSTS IN SOME OF THE WATERS...THEREFORE A GALE WARNING REMAINS IN EFFECT FOR THE CHARLESTON COUNTY WATERS. GALE WARNINGS MAY NEED TO BE EXPANDED FARTHER SOUTH...BUT FOR NOW GUSTS HAVE BEEN CAPPED AT 30 KT WITH SMALL CRAFT ADVISORIES IN EFFECT FOR ALL OTHER WATERS INCLUDING THE HARBOR. IF THE LOW BECOMES SUBTROPICAL IN NATURE...THEN THE GALE WARNING WOULD TRANSITION TO A TROPICAL STORM WARNING. IN ADDITION TO THE STRONG NORTHERLY FLOW...SEAS WILL REMAIN HAZARDOUS ALTHOUGH COULD DIMINISH AS THE FLOW VEERS A BIT MORE OFFSHORE. THE LOW PRESSURE SYSTEM OFF THE SOUTHEAST UNITED STATES COAST REMAINS EXTRATROPICAL AS OF LATE THURSDAY AFTERNOON. THE 12Z MODEL SUITE IS IN BETTER AGREEMENT...KEEPING THE LOW NEARLY STATIONARY OFF THE SC COAST THROUGH FRIDAY NIGHT BEFORE GRADUALLY SHIFTING IT WNW TOWARD THE SC COAST SATURDAY NIGHT. UNLESS THE SYSTEM BECOMES SIGNIFICANTLY STRONGER THAN CURRENTLY DEPICTED BY THE MODELS... LOCAL WIND IMPACTS WILL NOT CHANGE CONSIDERABLY FROM ONGOING FORECAST. WE HAVE A GALE WARNING THROUGH EARLY FRIDAY AFTERNOON FOR THE CHARLESTON SC NEARSHORE WATERS WHICH IS WHERE THE TIGHTEST GRADIENT WILL PERSIST IN ASSOCIATION WITH THE LOW. LATER IN THE DAY FRIDAY THE STRONGEST WIND FIELDS ARE EXPECTED TO SHIFT TO THE NORTHERN FLANK OF THE SYSTEM. MOST OF OUR WATERS WILL LIKELY REMAIN IN SMALL CRAFT ADVISORY CRITERIA THROUGH MUCH OF FRIDAY EXCEPT FOR THE GA NEARSHORE WATERS WHERE OFFSHORE FLOW WILL LIMIT FETCH. AS THE LOW MOVES CLOSER TO THE COAST AND WINDS SHIFT TO A MORE OFFSHORE FETCH...WINDS OVER MOST OF THE COASTAL WATERS MAY NOT EVEN BE IN SMALL CRAFT ADVISORY LEVELS. RIP CURRENTS...A HIGH RISK IN EFFECT ALL BEACHES FRIDAY DUE TO GUSTY WINDS AND MODERATE SWELLS. && .TIDES/COASTAL FLOODING... TONIGHT...INCREASING NORTH WINDS TONIGHT WILL RESULT IN ABOVE NORMAL TIDES ALONG THE COAST. A COASTAL FLOOD ADVISORY HAS BEEN ISSUED FOR THE LOWER SOUTH CAROLINA COAST LATE THIS EVENING INTO THE EARLY OVERNIGHT HOURS AS A RESULT. HIGH SURF...5-6 FT BREAKERS IN THE SURF ZONE AND A ROBUST HIGH TIDE IS LIKELY THIS EVENING. WITH SEAS RUNNING 6-9 FT WE HAVE EXTENDED THE HIGH SURF ADVISORY FOR THE CHARLESTON COUNTY COAST WITH A RISK OF BEACH EROSION INCREASING. NORTH FLOW SHOULD DAMPEN HIGH SURF RISK FURTHER SOUTH ALONG THE CURVED COASTLINE. FRIDAY...BREAKERS IN THE SURF ZONE WILL REMAIN HAZARDOUS ACROSS THE CHARLESTON COUNTY COAST THROUGH FRIDAY AFTERNOON AS THE LARGEST SEAS WILL BE OVER THE SC WATERS IN ASSOCIATION WITH THE OFFSHORE LOW. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...HIGH RISK FOR RIP CURRENTS THROUGH FRIDAY EVENING FOR GAZ117- 119-139-141. SC...HIGH RISK FOR RIP CURRENTS THROUGH FRIDAY EVENING FOR SCZ048>051. COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO 1 AM EDT FRIDAY FOR SCZ048>051. HIGH SURF ADVISORY UNTIL 6 PM EDT FRIDAY FOR SCZ050. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT FRIDAY FOR AMZ352. GALE WARNING UNTIL 2 PM EDT FRIDAY FOR AMZ350. SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR AMZ354. SMALL CRAFT ADVISORY UNTIL 5 PM EDT SATURDAY FOR AMZ374. SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT FRIDAY NIGHT FOR AMZ330. && $$ ST  FXUS62 KCHS 201636 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 1236 PM EDT Sat May 20 2017 .SYNOPSIS... High pressure will shift further offshore today. A cold front is expected to move through the region Monday night, followed by another front midweek. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... early afternoon update included subtle changes to temps and dew points based on recent trends, and also to alter the diurnal trend to show some rain-cooled conditions south and west of Hinesville where the better rain probabilities will occur. With 850 mb temps of 16-17C or close to 2 standard deviations above normal, afternoon highs will reach the upper 80s-lower 90s most places west of US-17. Sea breeze influences will "limit" max temps to the lower or middle 80s elsewhere. The Bermuda-Azores high will remain across the local region, while the mid and upper ridging that has been in place the past several days will begin to weaken as a strong cyclone moves through the central Great Plains. However, there is still a persistent cap across much of the CWFA that will maintain our stretch of rainfree weather. The exception will be across our interior SE GA zones, where isolated to scattered coverage will occur. This does not include Savannah, but does include Hinesville, Statesboro, Claxton, Reidsville and Metter. Activity will continue to develop along the sea breeze and differential heating boundaries from the morning stratus/fog, as well as forcing from a nearby impulse over south-central GA as seen on satellite imagery. Poor to okay lapse rates and limited moisture will prevent deep convection from developing, but MLCAPE is close to 2000 J/kg and certainly sufficient for convection. Due to DCAPE of 1250-1500 J/kg there could be stronger wind gusts in a couple of storms. Wet Bulb Zero (WBZ) is also low, around 9-10K ft, suggesting that small hail might also occur in isolated storms. Any severe risk is extremely low, but non-zero. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/... Tonight: Convection will gradually wind down across far interior Southeast Georgia as the sea breeze circulation clears the area and breaks down. Convection may linger across the CSRA and east-central Georgia into the late evening hours, possibly as late as early Sunday morning, as a region of enhanced H8 warm air advection /low-level jetting initiates there. However, this activity is expected to remain west of Southeast Georgia and Southeast South Carolina. Conditions favor a possible redevelopment of low-stratus across interior areas after midnight, but fog is not anticipated. Lows will range from the upper 60s/near 70 inland to the mid 70s at the beaches. Sunday through Tuesday: The upper ridge begins to break down as a series of shortwaves lift northeast from the central Gulf on Sunday. Deeper moisture will move into inland areas during the afternoon. Slightly more capping farther to the east will limit the potential for afternoon convection but farther inland we show scattered showers and thunderstorms. BLCAPEs are ~1,000 J/kg while lapse rates are marginal and shear is weak. Some stronger storms seem reasonable with a severe thunderstorm or two now out of the question, especially far inland where the parameters are the most conducive. The main threats would be wind and hail. A potent shortwave will push a strong cold front through the area on Monday. Deep moisture with PWs approaching 2" will support numerous showers/tstms and decent QPF. Isolated severe thunderstorms are possible. Though, we expect extensive cloud cover to limit instability. The cold front should be offshore Tuesday morning, but another cold front to the west will be approaching. Continued deep moisture across the area will support showers/tstms with decent QPF. With less favorable conditions for severe weather in place, the risk is low. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... Unsettled weather is forecasted Tuesday night through Wednesday night as another cold front slowly approaches and then crosses through the region. Drier conditions return Thursday as cool high pressure builds in from the west, persisting into Friday. Temperatures should be a few degrees below normal on Thursday. && .AVIATION /17Z SATURDAY THROUGH THURSDAY/... VFR to prevail through this evening. Risk for sub-VFR conditions will increase overnight with cigs possibly dropping as low as IFR at either terminal. Highest IFR probabilities remain west of both sites, so will not introduce sub-IFR cigs just yet. Extended Aviation Outlook: Occasional flight restrictions are expected Sunday afternoon through Wednesday as a series of cold fronts bring numerous showers/tstms. && .MARINE... This afternoon: Sub-tropical high pressure will hold firm, with the resulting ridge axis over the SC waters. This will cause SE or S winds at or below 12 kt, and in the absence of any appreciable swell the seas won't be any more than 2 or 3 ft. Tonight: Southerly wind regime will hold with Atlantic high pressure centered well offshore. Winds look to remain 10 kt or less with seas 2-3 ft. Sunday through Wednesday: The western periphery of Atlantic high pressure will be over the area Sunday. A cold front is forecasted to cross through the region Monday night, followed by another one midweek. Brief periods of gusty winds are possible with the frontal passage, but conditions won't be bad enough for Small Craft Advisories. Offshore flow develops late Wednesday as high pressure builds from the west. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM... SHORT TERM... LONG TERM... AVIATION... MARINE...  FXUS62 KCHS 201710 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 110 PM EDT Sat May 20 2017 .SYNOPSIS... High pressure will shift further offshore today. A cold front is expected to move through the region Monday night, followed by another front midweek. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... early afternoon update included subtle changes to temps and dew points based on recent trends, and also to alter the diurnal trend to show some rain-cooled conditions south and west of Hinesville where the better rain probabilities will occur. With 850 mb temps of 16-17C or close to 2 standard deviations above normal, afternoon highs will reach the upper 80s-lower 90s most places west of US-17. Sea breeze influences will "limit" max temps to the lower or middle 80s elsewhere. The Bermuda-Azores high will remain across the local region, while the mid and upper ridging that has been in place the past several days will begin to weaken as a strong cyclone moves through the central Great Plains. However, there is still a persistent cap across much of the CWFA that will maintain our stretch of rainfree weather. The exception will be across our interior SE GA zones, where isolated to scattered coverage will occur. This does not include Savannah, but does include Hinesville, Statesboro, Claxton, Reidsville and Metter. Activity will continue to develop along the sea breeze and differential heating boundaries from the morning stratus/fog, as well as forcing from a nearby impulseS over south-central GA and just off the coast of south coastal GA as seen on satellite imagery. Poor to okay lapse rates and limited moisture will prevent deep convection from developing, but MLCAPE is close to 2000 J/kg and certainly sufficient for convection. Due to DCAPE of 1250-1500 J/kg there could be stronger wind gusts in a couple of storms. Wet Bulb Zero (WBZ) is also low, around 9-10K ft, suggesting that small hail might also occur in isolated storms. Any severe risk is extremely low, but non-zero. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/... Tonight: Convection will gradually wind down across far interior Southeast Georgia as the sea breeze circulation clears the area and breaks down. Convection may linger across the CSRA and east-central Georgia into the late evening hours, possibly as late as early Sunday morning, as a region of enhanced H8 warm air advection /low-level jetting initiates there. However, this activity is expected to remain west of Southeast Georgia and Southeast South Carolina. Conditions favor a possible redevelopment of low-stratus across interior areas after midnight, but fog is not anticipated. Lows will range from the upper 60s/near 70 inland to the mid 70s at the beaches. Sunday through Tuesday: The upper ridge begins to break down as a series of shortwaves lift northeast from the central Gulf on Sunday. Deeper moisture will move into inland areas during the afternoon. Slightly more capping farther to the east will limit the potential for afternoon convection but farther inland we show scattered showers and thunderstorms. BLCAPEs are ~1,000 J/kg while lapse rates are marginal and shear is weak. Some stronger storms seem reasonable with a severe thunderstorm or two now out of the question, especially far inland where the parameters are the most conducive. The main threats would be wind and hail. A potent shortwave will push a strong cold front through the area on Monday. Deep moisture with PWs approaching 2" will support numerous showers/tstms and decent QPF. Isolated severe thunderstorms are possible. Though, we expect extensive cloud cover to limit instability. The cold front should be offshore Tuesday morning, but another cold front to the west will be approaching. Continued deep moisture across the area will support showers/tstms with decent QPF. With less favorable conditions for severe weather in place, the risk is low. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... Unsettled weather is forecasted Tuesday night through Wednesday night as another cold front slowly approaches and then crosses through the region. Drier conditions return Thursday as cool high pressure builds in from the west, persisting into Friday. Temperatures should be a few degrees below normal on Thursday. && .AVIATION /17Z SATURDAY THROUGH WEDNESDAY/... VFR to prevail into the overnight hours at KCHS and KSAV. The risk for flight restrictions will increase late with ceilings possibly dropping into the IFR category at either terminal. However, the highest IFR probabilities will remain west of both sites, so no worse then several hours of MVFR ceilings has been forecast from 08-14Z Sunday, before VFR conditions return late in the valid 18Z TAF cycle. Extended Aviation Outlook: Occasional flight restrictions are expected Sunday afternoon through Wednesday as a series of cold fronts bring numerous showers/tstms. && .MARINE... This afternoon: Sub-tropical high pressure will hold firm, with the resulting ridge axis over the SC waters. This will cause SE or S winds at or below 12 kt, and in the absence of any appreciable swell the seas won't be any more than 2 or 3 ft. Tonight: Southerly wind regime will hold with Atlantic high pressure centered well offshore. Winds look to remain 10 kt or less with seas 2-3 ft. Sunday through Wednesday: The western periphery of Atlantic high pressure will be over the area Sunday. A cold front is forecasted to cross through the region Monday night, followed by another one midweek. Brief periods of gusty winds are possible with the frontal passage, but conditions won't be bad enough for Small Craft Advisories. Offshore flow develops late Wednesday as high pressure builds from the west. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM... SHORT TERM... LONG TERM... AVIATION... MARINE...  FXUS62 KCHS 202348 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 748 PM EDT Sat May 20 2017 .SYNOPSIS... High pressure will continue to weaken across the area tonight. A series of low pressures will track across the Southeast Sunday through midweek, then a cold front will advance through our region Wednesday night into Thursday. High pressure will then prevail into next weekend. && .NEAR TERM /THROUGH SUNDAY/... This evening: Convection over our GA counties has been diminishing with the passing of the sea breeze and northwest translation of other convective outflow. Skies will remain mainly clear across southeast SC, except right along the Savannah River. Tonight: A backdoor cold front will drift southward across NC, as the western extension of sub-tropical high pressure pulls east. The deep ridging of the past several days will continue to break down and slide slowly east as a deep cyclone moves from the central Plains into the northern Plains. Convection will persist across the CSRA and east-central GA and outside the CWFA as low level jetting and isentropic ascent continues. Then a saturated boundary layer beneath the nocturnal inversion will support the formation of low stratus during the overnight hours. Since parts of SE GA will have wet grounds from today's rains, we have also added patchy fog to the forecast. Greatest coverage of the stratus and fog will occur mainly far NW tier of SC then over the western half of GA, mainly where the lower condensation pressure deficits will occur and where cross-over temps will be reached in several areas. Further east skies will average out to be mostly clear or partly cloudy. Most places won't fall any lower than the upper 60s and lower 70s within the light southerly synoptic flow, although a few mid 60s will be common in the Francis Marion Nat'l Forest where skies will remain mostly clear much of the night. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... An unsettled regime featuring periods of showers/thunderstorms and humid conditions will prevail through this period. Sunday: The upper ridge over the region will continue to break down in favor of a series of shortwaves ejecting northeast from the parent upper trough west of the region. As a result, regime featuring deeper moisture/more numerous thunderstorms west/southwest of the forecast area will shift into the forecast area. However, a rather sharp west/east moisture gradient will persist, and thunderstorms will most likely remain west of the SC coast including the Charleston Tri-County region. Thus, POPs ramp up to likely west of I-95 Sunday afternoon but remain below 15 percent with no mention of precipitation along the SC coast. A few thunderstorms could briefly become severe and could produce locally heavy rain inland Sunday afternoon/early evening, but significant severe weather/flooding is not expected. Otherwise, high temps in the mid/upper 80s will be common away from the beaches, but cooler temperatures could develop inland if thunderstorms attain expected coverage Sunday afternoon. Sunday night: Coverage of showers/thunderstorms should decrease to some degree due to diurnal trends, but slight chance/chance POPs remain in order along/west of I-95 as a complex shortwave trough aloft pushes into the region. Also, patchy fog could develop along/west of I-95 late Sunday night/early Monday morning. Monday: A plume of PWATs around 2 inches will spread farther east into the forecast area, and a shortwave trough will interact with this moisture and various mesoscale boundaries to produce numerous/widespread showers/thunderstorms. Following the progress of the shortwave and associated deepest moisture, likely/categorical POPs are in order most areas with highest POPs inland through midday then shifting toward the coast during the afternoon. Isolated/brief episodes of severe weather are possible, but the potential for locally excessive rainfall will remain somewhat greater. Even so, significant flooding is not anticipated. The latest forecast advertises high temps in the lower/mid 80s, attainable between showers/thunderstorms. Monday night/Tuesday: Patchy fog could develop late Monday night into Tuesday. Otherwise, details regarding POPs remain more uncertain due to the uncertain timing of the exit of an initial shortwave, the potential for brief drying in the wake of this feature, and the uncertain timing of the next shortwave. For now, this forecast maintains likely POPS near the coast Monday evening, then downgrades POPs to chance overnight. Tuesday, likely POPs are justified all areas, but higher POPs could be required inland Tuesday AM and toward the coast Tuesday PM. Expect adjustments to this forecast as details come into focus over the next couple of days. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... Unsettled weather is forecasted Tuesday night through Wednesday night as another cold front slowly approaches and then crosses through the region. Drier conditions return Thursday as cool high pressure builds in from the west, persisting into Friday. Temperatures should be a few degrees below normal on Thursday. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... VFR to prevail into the overnight hours. The risk for flight restrictions will increase late with ceilings possibly dropping into the IFR category at either terminal. However, the highest IFR probabilities will remain west of both sites, so no worse then several hours of MVFR ceilings has been forecast from 08-14Z Sunday, before VFR conditions return late in the valid 18Z TAF cycle. Models continue to indicate convective rains will have a better chance impacting areas along and to the west of I-95 Sunday afternoon and thus we have mention of CB at KSAV. Extended Aviation Outlook: Periods of flight restrictions are likely as an unsettled pattern prevails through midweek. && .MARINE... Tonight: The Bermuda-Azores high will gradually relax it's grip across the local waters, allowing a backdoor cold front over and offshore of NC to drop southward, but still staying well to the north through the night. Even with lingering sea breeze circulations into this evening, SE and S winds won't be any greater than 10 or 15 kt, before dropping off several knots late. The lack of any appreciable swell energy means that seas won't be able to muster anything higher than 2 or 3 ft. Sunday through Wednesday: The region will remain between offshore high pressure and a series of inland low pressures. S/SW winds 10-15 knots with gusts to 20 knots and associated seas of 2-4 feet nearshore/4-5 feet beyond 20 nm should prevail, and Small Craft Advisory conditions are not expected. However, thunderstorms could produce locally gusty winds, lighting and heavy rain, especially Monday through Wednesday. Thursday, a cold front will cross the waters, and winds will turn offshore. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM... SHORT TERM... LONG TERM... AVIATION... MARINE...  FXUS62 KCHS 090741 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 341 AM EDT Sun Jul 9 2017 .SYNOPSIS... A weak cold front will drop into the area today before dissipating. The area will then remain situated between an inland trough and Atlantic high pressure for the rest of the week before another cold front approaches early next week. && .NEAR TERM /THROUGH TONIGHT/... As of 320 AM: Latest IR satellite indicated SCT to BKN high clouds over the CWA, developing along and east of H5 trough. The satellite water vapor channel indicated a fairly uniform band of moisture across the Atlantic coast south to the Gulf of Mexico. The W/V loop indicated that the western edge of the moisture was slowly pushing east across Piedmont of the Carolinas and the foothills of GA. GFS simulated W/V indicates that mid level dry air may reach the Coast Plain from the NW this afternoon. At the sfc, a weak cold front is forecast to stall west of I-95 during the daylight hours today. Forecast soundings and plain view of the NAM12 and GFS indicate that conditions will begin to destabilize from the Atlantic early this morning, spreading inland through the morning. By early afternoon, normalized CAPE values should range from 0.1 to 0.2 m/s2 across the CWA. Deep convection will likely develop initially along the border of the moist and dry mid level air this morning into the afternoon, then along sea breeze during the mid to late afternoon. PW values are forecast to range from 2-2.25 inches with warm cloud thickness around 11 kft. Drifting storms may produce periods of torrential to heavy downpours. Although DCAPE values are forecast to remain less than 1000 J/kg, one or two strong to severe wind gusts are possible. High temperatures are forecast to range from the upper 80s to the low 90s. Tonight, the stationary front should gradually dissipate, leaving a broad trough over the CWA overnight. Convection during the afternoon and evening may work over the environment, resulting in a slow reduction of deep convection. I will forecast decreasing PoPs during the night, but generally remaining with CHC values. Low temperatures are forecast to range from the low to mid 70s. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... General troughing will give way to more ridging toward mid week as the Atlantic high builds westward across the Southeast U.S. In addition, abundant moisture and some shortwave energy are expected, mainly into Tuesday. This pattern will result in above normal rain chances through Tuesday with more normal chances Wednesday. High temperatures will generally be in the lower 90s for most locales, although some mid 90s are possible Wednesday. High humidity will yield heat heat indices near 100 inland each day through Tuesday and up near 105 degrees Wednesday (mainly in GA). Low temperatures should be above normal in the mid 70s for most places. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... Atlantic high pressure will prevail through Friday before another upper trough, cold front and pre-frontal trough return next weekend. This pattern should lead to generally typical summertime weather through Thursday with increasing rain chances late in the week through the weekend. High temperatures should mostly be near to slightly above normal in the mid 90s with heat indices close to 105 degrees while low temperatures remain above normal in the mid to upper 70s. && .AVIATION /08Z SUNDAY THROUGH THURSDAY/... KCHS received a little more than a quarter of an inch around midnight. The rainfall lowered the KCHS dewpoint depression to around 3 degrees, with the dewpoint of 72 degrees. Debris clouds will likely thin gradually through the pre dawn period. There is potential for ground fog or brief fog if sky cover totally erodes. However, upstream high clouds should slide east, filling in voids left by the debris clouds. I will not mention fog at this time. The primary forecast challenge will be the thunderstorm placement and timing. Water vapor loop indicated that the western edge of a band of moisture was pushing into the Piedmont. Based on the current satellite trends, the drier air should reach the western Coastal Plain during the late afternoon hours. At the sfc, the cold front is expected to push east from the Midlands. Deep convection should develop along the leading edge of the mid level dry and sfc front, with storm motions from the NW. TAFs will feature SSW winds, peaking in the afternoon around 10 kts. I will include a TEMPO from 20Z to 1Z for TSRA, MVFR vis/cigs, and gusty winds. Extended Aviation Outlook: Flight restrictions at times through the period, mainly from afternoon/evening showers and thunderstorms. && .MARINE... A weak cold front is expected to approach the GA/SC coast this afternoon, becoming nearly stationary inland. The pressure gradient across the marine zones will remain weak through tonight. Winds should remain from the SSW between 10-15 kts. Wave heights are forecast to range 2-4 feet through tonight. Conditions will remain below Small Craft Advisory criteria. Coverage of thunderstorms should become scattered to numerous across the marine zone late this afternoon and evening. These storms may produce gusty winds and occasional cloud to surface lightning. Monday through Friday: The area will remain between inland troughing and Atlantic high pressure. This will maintain a moderate southerly flow through the period, enhanced at times due to the afternoon sea breeze and nighttime surging. No Advisories are anticipated however given winds 20 knots or less and seas mainly 3 feet or less. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...NED SHORT TERM...RJB LONG TERM...RJB AVIATION...NED/RJB MARINE...NED/RJB