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 201030 AFDCHS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 630 AM EDT THU MAR 20 2014 .SYNOPSIS... A DRY COLD FRONT WILL PUSH OFFSHORE THIS MORNING. WEAK HIGH PRESSURE WILL PREVAIL OVERNIGHT. A DRY COLD FRONT WILL PUSH THROUGH THE REGION THURSDAY. HIGH PRESSURE WILL QUICKLY MOVE EAST THROUGH THE AREA FRIDAY AND OFFSHORE SATURDAY. A STRONGER COLD FRONT WILL THEN PUSH THROUGH SUNDAY NIGHT WITH HIGH PRESSURE BUILDING FROM THE NORTH WHILE A STORM SYSTEM MOVES ALONG THE SOUTHEAST COAST MONDAY NIGHT INTO TUESDAY. COLDER HIGH PRESSURE WILL THEN EXPAND OVER THE AREA THROUGH THE MIDDLE OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A TIMELY SUOMI NPP VIIRS NIGHTTIME VISIBLE SATELLITE IMAGE SHOWS THE CIRRUS DECK IS NOT NEARLY AS THICK AS EXPECTED. THE CLOUD COVER FORECAST HAS BEEN ADJUSTED THROUGH MID-MORNING TO TAKE THIS INTO ACCOUNT. LOW-LEVEL WIND FIELDS ARE BEGINNING TO PICK UP SOME AS A COLD FRONT APPROACHES. VISIBILITIES ARE IMPROVING AS A RESULT. THE ONLY EXCEPTION IS ACROSS THE FAR SOUTH WHERE VISIBILITIES CONTINUE TO DROP. JESUP RECENTLY REPORTED A VISIBILITY OF 1/2 MILE AND FORT STEWART WAS AT 2 MILES AS OF 20/1015Z. A SPECIAL WEATHER STATEMENT HAS BEEN ISSUED FOR LONG...BRYAN AND LIBERTY COUNTIES TO ADDRESS LOCALLY DENSE FOG THROUGH SUNRISE. A DENSE FOG ADVISORY IS NOT EXPECTED ATTM. THE REMAINDER OF THE FORECAST IS ON TRACK. TODAY...A DRY COLD FRONT WILL PUSH OFFSHORE THIS MORNING AS THE SUPPORTING UPPER TROUGH PIVOTS ACROSS THE NORTHEAST STATES. BROAD HIGH PRESSURE CURRENTLY STRETCHING FROM CENTRAL TEXAS INTO WESTERN TENNESSEE WILL PROPAGATE TO THE WEST...EXTENDING ACROSS THE SOUTHEAST U.S. LATER THIS AFTERNOON. THE BAND OF CIRRUS ASSOCIATED WITH A POWERFUL 130 KT JET STREAK IS FORECAST TO EXIT OFF TO THE EAST AND SOUTHEAST LATER THIS MORNING. FORECAST SOUNDINGS SHOW VERY LITTLE MOISTURE REMAINING IN THE WAKE OF THE FRONT...SO EXPECT A SUNNY DAY ONCE THE HIGH CLOUDS EXIT OFFSHORE. LOW-LEVEL THICKNESS SCHEMES SUPPORT HIGHS IN THE LOWER-MID 70S WHICH LOOK REASONABLE. THERE ARE SOME HINTS THAT A WEAK SEA BREEZE COULD DEVELOP LATE THIS AFTERNOON AS LAND/OCEAN THERMAL DIFFERENTIALS APPROACH 15-20 DEGREES...BUT THE WEST/NORTHWEST POST-FRONTAL LOW- LEVEL WIND FIELD SHOULD KEEP ANY SUCH CIRCULATION NEAR OR JUST OFF THE COAST. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... TONIGHT...HIGH PRESSURE WILL BE CENTERED OVER THE AREA TONIGHT. THE BOUNDARY LAYER WILL DECOUPLE QUICKLY AFTER SUNSET YIELDING LIGHT TO CALM WINDS. THESE CONDITIONS ALONG WITH CLEAR SKIES WILL SUPPORT A SOLID RADIATIONAL SETUP. OPTED TO TREND LOWS DOWN A FEW DEGREES FROM THE PREVIOUS FORECAST CLOSER TO THE COOLER MAV-COOP AND ECMWF MOS DATA SETS. LOWS WILL RANGE FROM THE UPPER 30S/NEAR 40 INLAND...LOWER/MID 40S AT THE COAST AND UPPER 40S/LOWER 50S AT THE BEACHES. COULD SEE SOME VERY LIGHT/PATCHY FROST IN OUTLYING AREAS ACROSS PORTIONS OF JENKINS-SCREVEN AND ALLENDALE COUNTIES WHERE A FEW MID 30S COULD OCCUR...BUT THE EXPECTED COVERAGE IS NOT ENOUGH TO JUSTIFY A FROST ADVISORY AT THIS TIME. FRIDAY...QUIET/DRY CONDITIONS ARE EXPECTED TO START OFF THE WEEKEND AS BROAD HIGH PRESSURE CENTERED OVER THE SOUTHEASTERN UNITED STATES GRADUALLY SHIFTS OFFSHORE THROUGH FRIDAY EVENING. THE SHIFT OFFSHORE WILL LIKELY LEAD TO WARMER TEMPS THAN THE PREVIOUS DAY AS A SOUTHERLY FLOW DEVELOPS ALONG THE WESTERN EDGE OF THE HIGH OFFSHORE WHILE A DOWNSLOPING WIND COMPONENT CONTINUES OFF THE SFC. HIGH TEMPS SHOULD RANGE IN THE MID 70S AWAY FROM THE COAST...WARMEST IN SOUTHEAST GEORGIA. OVERNIGHT LOWS WILL ALSO SHOW A WARMER TREND...WITH TEMPS ONLY DIPPING INTO THE LOW/MID 50S AWAY FROM THE COAST. SATURDAY...SOUTHERLY FLOW WILL CONTINUE ALONG THE WESTERN EDGE OF HIGH PRESSURE OFFSHORE...RESULTING IN SOME MOISTURE RETURN TO THE AREA AND EVEN WARMER TEMPS FOR THE DAY. OVERALL HIGH TEMPS SHOULD RANGE IN THE MID/UPPER 70S OVER MOST LOCATIONS AWAY FROM THE COAST...AGAIN WARMEST IN SOUTHEAST GEORGIA. WE COULD SEE A PERIOD OF SHOWERS ALONG THE COAST BEFORE THE SFC FLOW BECOMES MORE SOUTHWEST BY THE SATURDAY AFTERNOON/EVENING. HAVE THEREFORE MAINTAINED A SLIGHT CHANCE OF SHOWERS THROUGHOUT THE DAY WITH BEST CHANCES ALONG THE COAST. OVERNIGHT LOWS WILL REMAIN MILD...IN THE MID/UPPER 50S. SUNDAY...THE DAY SHOULD START OFF WARM AND MAINLY DRY AHEAD OF A COLD FRONT APPROACHING FROM THE NORTHWEST. TEMPS SHOULD WARM INTO THE LOW/MID 70S. PRECIP CHANCES SHOULD THEN INCREASE SUNDAY AFTERNOON AND EVENING WHILE H5 SHORTWAVE ENERGY SHIFTS OVER THE SOUTHEAST IN ADVANCE OF THE COLD FRONT PUSHING THROUGH THE AREA STARTING SUNDAY EVENING. A FEW THUNDERSTORMS ARE NOT OUT OF THE QUESTION GIVEN ENHANCED MID/UPPER LVL WIND FIELDS ALONG WITH THE ARRIVING FRONT. HOWEVER...A LACK OF DEEP MOISTURE AND STRONG SFC HEATING SHOULD RESULT IN LIMITED INSTABILITY...THUS HAVE OPTED TO KEEP ANY MENTION OF THUNDER OUT OF THE FORECAST FOR THE TIME BEING. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... CHANCES OF SHOWERS SHOULD BE ONGOING WITH A COLD FRONT SHIFTING THROUGH THE AREA SUNDAY NIGHT. TEMPS WILL THEN BE MUCH COLDER AND WELL BELOW NORMAL POST FROPA AS HIGH PRESSURE BUILDS OVER THE REGION FROM THE NORTH/NORTHWEST. EXPECT OVERALL HIGH TEMPS ONLY IN THE MID/UPPER 50S OVER SOUTHEAST SOUTH CAROLINA AND NEAR 60 OVER SOUTHEAST GEORGIA INTO MIDWEEK. CHANCES OF SHOWERS SHOULD ALSO INCREASE MONDAY INTO EARLY TUESDAY AS A SERIES OF MID LVL SHORTWAVES SHIFT OVER THE AREA WHILE A LOW PRESSURE SYSTEM TRACKS ALONG THE SOUTHEAST COAST. DRY AND EVEN COLDER HIGH PRESSURE IS THEN EXPECTED TO EXPAND OVER THE REGION THROUGH MID WEEK AS THE LOW PRESSURE SYSTEM DEPARTS FURTHER OFFSHORE AND TO THE NORTHEAST. OVERNIGHT LOWS WILL BE QUITE COLD TUESDAY AND WEDNESDAY NIGHT...WITH TEMPS DIPPING INTO THE MID 30S INLAND TO LOW/MID 40S ALONG THE COAST. TEMPS SHOULD GRADUALLY WARM INTO THE LOW 60S ON THURSDAY AS HIGH PRESSURE BEGINS TO SLIP OFFSHORE. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... VFR. EXTENDED AVIATION OUTLOOK...LOW CHANCES OF MVFR CIGS/VSBYS SUNDAY NIGHT INTO EARLY MONDAY WITH A PASSING COLD FRONT...THEN HIGHER CHANCES OF MVFR CIGS/VSBYS MONDAY NIGHT AS A LOW PRESSURE SYSTEM TRACKS ALONG THE SOUTHEAST COAST. && .MARINE... TODAY...SOUTHWEST WINDS WILL VEER WEST AFTER SUNRISE AS A COLD FRONT SHIFTS OFFSHORE. WINDS WILL THEN TURN MORE SOUTHERLY THIS AFTERNOON NEAR THE COAST AS A WEAK SEA BREEZE CIRCULATION TRIES TO TAKE SHAPE. WINDS WILL BE LESS THAN 10 KT FOR THE ENTIRE DAY. SEAS WILL AVERAGE 1-3 FT NEARSHORE WATERS AND 3-5 FT OFFSHORE WATERS. TONIGHT...WINDS WILL TURN NORTHEAST AFTER MIDNIGHT IN RESPONSE TO HIGH PRESSURE SHIFTING INTO THE SOUTHEAST STATES. SOMEWHAT OF A PINCHED GRADIENT IS FORECAST TO DEVELOP ACROSS THE WATERS EARLY FRIDAY MORNING...WHICH WILL SUPPORT WINDS AROUND 10-15 KT. THE LATEST NAM GUIDANCE SUGGESTS WINDS COULD BE A LITTLE STRONGER THAN THAT...CLOSER TO 15-20 KT...ESPECIALLY ALONG THE LOWER SOUTH CAROLINA COAST...BUT NOT QUITE READY TO FORECAST CONDITIONS THAT HIGH JUST YET. SEAS WILL RANGE 1-2 FT NEARSHORE WATERS TO 2-4 FT OFFSHORE WATERS. FRIDAY THROUGH MONDAY...WINDS/SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY LEVEL CONDITIONS THROUGH THE WEEKEND AS BROAD HIGH PRESSURE GRADUALLY SLIDES OFF THE SOUTHEAST COAST. IN GENERAL...SOUTH TO SOUTHWEST WINDS WILL REMAIN AT OR BELOW 15 KTS WHILE SEAS BUILD NO HIGHER THAN 4 FT...HIGHEST OVER OUTER GEORGIA WATERS. A COLD FRONT WILL THEN PUSH OFFSHORE SUNDAY NIGHT...WITH DETERIORATING CONDITIONS OVER ALL WATERS INTO EARLY NEXT WEEK. WINDS/SEAS WILL LIKELY REACH SMALL CRAFT ADVISORY LEVEL CONDITIONS FOR MOST WATERS BY EARLY MONDAY AS THE PRESSURE GRADIENT BECOMES ENHANCED BETWEEN STRONGER HIGH PRESSURE BUILDING INLAND AND A LOW PRESSURE SYSTEM TRACKING ALONG THE SOUTHEAST COAST THROUGH MIDWEEK. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$  FXUS62 KCHS 161042 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 642 AM EDT TUE AUG 16 2016 .SYNOPSIS... Atlantic high pressure will prevail through Wednesday then weaken. A strengthening inland trough will bring unsettled weather Thursday through the weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Decided to go ahead and introduce a 20% rain chance for the Charleston Metro area from mid-morning through very early in the afternoon per steady trends from the RAP and H3R. Also initialized sky grids with a bit more cloud cover along the coast per latest VIIRS nighttime visible satellite imagery. Today: A persistent blocking pattern will remain in tact today across the Southeast U.S. with an expansive 598 dam anticyclone holding firm. Similar the past several days, the amount of convection will be well below climatological normals for mid- August given warm mid-level temperatures and some subsidence aloft. Expect another round of isolated showers/tstms to develop this afternoon within a weakly unstable airmass, mainly centered ahead of the pure sea breeze circulation. 20% pops look reasonable for this afternoon. Highs will range from the mid-upper 90s inland to the upper 80s at the beaches. The Savannah/Hilton Head International Airport is poised to see its 56th consecutive day of highs 90 degree or warmer, tying the period ending July 14th, 2011, with the longest span consecutive 90+ degree days. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... Tonight: Any spotty shower/tstm activity early will quickly dissipate after sunset. Expect another dry night, otherwise. Isolated showers/tstms could redevelop over the coastal waters after midnight, especially near the western all of the Gulf Stream, but any such activity should remain away from land. Could see patchy stratus and fog form after midnight, mainly in areas that receive spotty rainfall this afternoon. Lows will range from the mid 70s inland to around 80 at the coast and Downtown Charleston. Few instances of lows in the lower 70s will be possible in sheltered areas well inland. Wednesday through Friday: Atlantic high pressure will be in place Wednesday, resulting in a typical summertime pattern. Models show gradually increasing PWATs, but they also indicate an area of PWATS less than 1.5" over a portion of our area. The exact location and size of this area varies per model, but they all seem to show it in some form, which would limit the convective potential. Given the variations and uncertainties, opted to go with slight chance POPs for the entire area. But this will probably need to be changed depending on what the upcoming model runs show. As we head into Wednesday night, the Atlantic high will begin to weaken/retreat east as a mid/upper level disturbance passes over the Mid-Atlantic states. The pattern should allow a trough to develop along the Southeast coast and PWATs to rise to 1.75-2" by Thursday. The increased moisture and forcing will support higher chances of showers and thunderstorms Thursday and Friday afternoon/evening, especially as the seabreeze moves inland. High temperatures will remain a few degrees above normal on Wednesday (the lower to mid 90s) as the Atlantic high maintains a hold over the Southeast. Thursday and Friday temperatures could make a run for the lower 90s across most of the area, but the limiting factor could be the precipitation coverage and when it begins. The earlier, the less maximum heating. The later, the more maximum heating. Overnight lows will remain mild each night, in the mid to upper 70s away from the coast. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... The upper air pattern will consist of a weak ridge moving over the northeastern states Friday night while heights gradually trend downward across the southeastern states. Saturday and Sunday the ridge axis will shift offshore while a strong upper level trough develops over the central U.S. The trough is forecasted to move over the east coast on Monday. At the surface, a trough should stay stretched across the southeast U.S. through the weekend. A cold front is expected to approach our area by late in the long term. This general weather pattern will lead to plenty of moisture and instability across our area during the long term. Expect good coverage of showers and thunderstorms, especially each afternoon, possibly lasting well into the nights. Additional convection should occur ahead of the front. As for temperatures, they will be near normal for this time of year. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... VFR. Could see isolated showers in the vicinity of KSAV and KCHS from roughly 15-18z, but no impacts are expected given they should be fairly small. Extended Aviation Outlook: brief flight restrictions are possible with showers and thunderstorms Thursday through Saturday. && .MARINE... Today: A prevailing southeast flow regime will hold today with winds generally 10 kt or less. Some weak enhancement could occur along the land/sea interface and Charleston Harbor as the pure sea breeze circulation moves inland, but any enhancement is not expected to be significant. Seas will average 2-3 ft. Tonight: Southeast winds will gradually veer to the south through the night. Speeds will will remain less than 10 kt with seas 1-2 ft nearshore waters and 2-3 ft offshore waters. Wednesday through Saturday: Atlantic high pressure will bring south/southeast winds up to 10-15 kt Wednesday with seas 2-3 ft. Thursday the high will gradually weaken and move eastward while an upper-level disturbance passes north of our area. This synoptic pattern will support slightly higher winds, peaking around 15 kt Thursday night through Saturday. Winds should be the highest with the afternoon seabreeze and during nocturnal surging. Seas will be 2-3 ft. && .CLIMATE... Below are the top 5 runs of consecutive days with a high temperature of at least 90 degrees at the Savannah/Hilton Head International Airport (KSAV). Temperature records date back to 1874. 1. 56, ended 7/14/2011... 2. 55, ongoing through 8/15/2016... 3. 44, ended 8/8/1993... 4. 40, ended 8/14/2010... 5. 38, ended 9/2/2011... Below are the top 5 runs of consecutive days with a minimum temperature of 75 or warmer at the Charleston International Airport (KCHS). Temperature records date back to 1938. 1. 24, ongoing through 8/15/2016... 2. 16, ended 8/2/2011... 3. 15, ended 7/22/1981... 4. 14, ended 8/2/1999... 5. 12, ended 7/21/1988... Record high minimum temps for August 16th... KCHS: 78 set in 2010 and previous... KCXM: 82 set in 2007... KSAV: 78 set in 1942 and previous... && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ ST