National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
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