026  
FXUS62 KCHS 290813  
AFDCHS  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHARLESTON SC  
413 AM EDT WED MAR 29 2017  
   
SYNOPSIS
 
 
A WEAK FRONT WILL SAG SOUTH OVER THE AREA TODAY, THEN MOVE NORTH AS  
A WARM FRONT THURSDAY NIGHT. A COLD FRONT WILL MOVE THROUGH FRIDAY  
NIGHT FOLLOWED BY DRY HIGH PRESSURE INTO SUNDAY. UNSETTLED WEATHER  
SHOULD RETURN AGAIN NEXT MONDAY, POSSIBLY LASTING INTO TUESDAY.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
PRE-DAWN: TRANQUIL CONDITIONS WILL PERSIST WITH MAINLY CLEAR  
SKIES AND LIGHT/VARIABLE WINDS. THERE COULD BE SOME PATCHY  
GROUND FOG IN SPOTS WERE SOME OF THE SHOWERS FELL YESTERDAY  
IN SOUTHEAST SC, NO SIGNIFICANT VSBY REDUCTIONS ARE ANTICIPATED.  
 
TODAY: MID AND UPPER LEVEL RIDGING WILL BUILD ACROSS THE GA AND  
THE CAROLINAS, MAINTAINING ABOVE AVERAGE TEMPERATURES AND  
GENERALLY DRY WEATHER. SURFACE HIGH PRESSURE BUILDING TO THE  
NORTHWEST AND NORTH, WILL PUSH A WEAK COLD FRONT INTO THE  
FORECAST AREA. THERE IS NOT MUCH OF A THERMAL GRADIENT WITH THE  
FRONT AND IT'S MAIN IMPACT WILL BE SUBTLE WIND SHIFTS THIS  
MORNING OVER SOUTH CAROLINA. HIGH TEMPS WILL ONCE AGAIN BE IN  
THE MID 80S MANY AREAS TODAY, THE BEACHES AND BARRIER ISLANDS  
SHOULD REMAIN QUITE A BIT COOLER WITH ONSHORE AFTERNOON FLOW. WE  
HAVE A SLIGHT CHANCE OF BRIEF SHOWERS WITH THE SEA BREEZE  
CLOSER TO THE ALTAMAHA RIVER LATER THIS AFTERNOON BUT TOO MUCH  
SUBSIDENCE ALOFT TO SUPPORT ANY DEEPER CONVECTION.  
 
TONIGHT: A BIT OF TRICKY FORECAST WITH A LIGHT ONSHORE AND  
UPSLOPE FLOW. THIS SYNOPTIC PATTERN ALONG WITH ELEVATED SURFACE  
DEW POINTS FAVOR SOME STRATUS DEVELOPMENT OVERNIGHT AND THIS  
WAS SUPPORTED BY SEVERAL 00Z MODEL SOLUTIONS. WITH LOW LEVEL  
WINDS PICKING UP A BIT LATE, IT LOOKS A BIT DOUBTFUL WE WILL SEE  
SIGNIFICANT FOG FROM BUILD-DOWN STRATUS, BUT THERE WAS ENOUGH  
EVIDENCE TO INTRODUCE SOME PATCHY FOG AROUND THE SAVANNAH RIVER  
ENTRANCE SOUTH INTO COASTAL GA. LOWS WILL BE IN THE UPPER 50S  
NORTH TO LOWER 60S SOUTH.  
 

 
   
SHORT TERM /THURSDAY THROUGH SATURDAY/
 
 
A STALLED FRONT ACROSS SOUTHEAST GA THURSDAY WILL SHIFT NORTH AS A  
WARM FRONT THURSDAY NIGHT FOLLOWED BY A COLD FRONT FRIDAY NIGHT.  
RAIN CHANCES WILL RAMP UP TOWARD THURSDAY AFTERNOON WHEN DEEPER  
MOISTURE AND ISENTROPIC ASCENT INCREASE ACROSS THE AREA. THUS,  
SHOWERS AND POSSIBLY A FEW THUNDERSTORMS (MAINLY ACROSS GA) ARE  
EXPECTED THURSDAY AFTERNOON/EVENING WITH A LULL LIKELY, ESPECIALLY  
ACROSS GA, BEFORE INCREASING AGAIN TOWARD DAYBREAK FRIDAY AS  
STRONGER SYNOPTIC FORCING ARRIVES. PRECIPITATION SHOULD TAPER OFF  
LATER FRIDAY AS THE DEEPEST MOISTURE SHIFTS NORTHEAST OF THE AREA.  
ALTHOUGH WIND FIELDS WILL BE STRONG FRIDAY, INSTABILITY APPEARS  
MINIMAL AND THUS THE THREAT FOR SEVERE WEATHER IS LOW AT THIS TIME.  
EITHER WAY IT SHOULD BE A BREEZY DAY WITH GUSTS UP TO AROUND 25-30  
MPH. ANY LINGERING SHOWERS NEAR THE SC COAST SHOULD END FRIDAY  
EVENING AS A COLD FRONT MOVES THROUGH WITH DRY CONDITIONS THE REST  
OF THE NIGHT INTO SATURDAY.  
 
ON THURSDAY TEMPERATURES WILL BE A BIT COOLER THAN WEDNESDAY BEHIND  
THE FRONT, ESPECIALLY ACROSS SC WHERE IT SHOULD STAY BELOW 80  
DEGREES EXCEPT CLOSE TO THE SAVANNAH RIVER. TEMPERATURES FRIDAY WILL  
BE MODERATED BY THE CLOUDS/RAIN, LIKELY ONLY REACHING CLOSE TO 80  
INLAND WITH A SLIGHT WARMUP SATURDAY AS SLIGHT COOL ADVECTION LIKELY  
GETS OVERCOME BY SOME DOWNSLOPE WARMING.  
 

 
   
LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/
 
 
DRY HIGH PRESSURE TO PREVAIL THROUGH SUNDAY NIGHT ALTHOUGH MOISTURE  
WILL BE INCREASING TOWARD MONDAY MORNING AS LOW-LEVEL JETTING RAMPS  
UP AHEAD OF APPROACHING LOW PRESSURE FROM THE WEST. UNSETTLED  
WEATHER IS EXPECTED MONDAY INTO TUESDAY ALTHOUGH TIMING IS A BIT  
UNCERTAIN AT THIS POINT. MID-LEVEL RIDGING SHOULD KEEP THINGS DRY  
AND QUITE WARM WEDNESDAY, POSSIBLY NEAR RECORD LEVELS IN GA.  
OTHERWISE, TEMPERATURES SHOULD REMAIN ABOVE NORMAL THROUGH THE  
PERIOD.  
 

 
   
AVIATION /08Z WEDNESDAY THROUGH SUNDAY/
 
 
VFR AT KSAV AND KCHS THROUGH 06Z THURSDAY. SMALL CHANCES FOR  
LOWER CIGS DEVELOPING/ADVECTING OFF THE ATLANTIC LATER TONIGHT.  
 
EXTENDED AVIATION OUTLOOK: RESTRICTIONS LIKELY DUE TO  
SHOWERS/THUNDERSTORMS/LOW CLOUDS, MAINLY THU NIGHT INTO FRI. BREEZY  
CONDITIONS EXPECTED FRI.  
 

 
   
MARINE
 
 
TODAY: A WEAK COLD FRONT WILL DRIFT INTO THE WATERS TODAY AND  
LOSE DEFINITION LATE AS IT MINGLES WITH THE SEA BREEZE  
OSCILLATIONS. WINDS WILL GRADUALLY VEER ONSHORE AND INCREASE  
CLOSE TO 15 KT ACROSS CHARLESTON WATERS BY EARLY THIS EVENING  
INTO TONIGHT. GA WATERS WILL SEE LIGHT OFFSHORE WINDS EARLY THIS  
MORNING BECOMING ONSHORE LATER TODAY AND TONIGHT, SPEEDS WILL  
BE CLOSER TO 10 KT. SEAS WILL AVERAGE 2-3 FT NEAR SHORE WITH 3-4  
FT OFFSHORE AND SOME 5 FOOTERS OUT CLOSER TO THE GULF STREAM.  
 
THURSDAY THROUGH MONDAY: A WARM FRONT WILL SHIFT NORTH THROUGH THE  
AREA THURSDAY NIGHT/FRIDAY. A COLD FRONT WILL THEN MOVE THROUGH  
FRIDAY NIGHT/EARLY SATURDAY. AT SOME POINT PRIOR TO THE COLD FRONTAL  
PASSAGE SEA FOG COULD DEVELOP ACROSS THE COOLER NEAR SHORE WATERS  
AND LEAD TO LOW VISIBILITIES. CONDITIONS WILL GO DOWNHILL AGAIN  
MONDAY AS A STORM SYSTEM APPROACHES FROM THE WEST.  
 
EXPECT A HIGH CHANCE FOR ADVISORIES THURSDAY NIGHT ACROSS THE OUTER  
WATERS, EXPANDING NORTHWARD INTO THE SC WATERS INTO FRIDAY NIGHT AS  
STRENGTHENING WINDS BUILD SEAS TO 6-7 FEET, HIGHEST TOWARD THE GULF  
STREAM.  
 
RIP CURRENTS: MODERATE RISK FOR RIP CURRENTS ALONG THE SC COAST  
TODAY. WINDS BECOMING ONSHORE AND INCREASING LATE ALONG WITH  
LONG PERIOD 2-3 FOOT SWELLS MAY PRODUCE RIP CURRENTS. THE  
COMBINATION OF HIGHER THAN NORMAL TIDES, ONSHORE WINDS AND  
SWELLS IN THE SURF ZONE WILL SUPPORT AN ENHANCED RISK FOR RIP  
CURRENTS, POSSIBLY LASTING INTO FRIDAY.  
 

 
   
TIDES/COASTAL FLOODING
 
 
STRENGTHENING ONSHORE WINDS COMBINED WITH SWELLS IMPACTING THE COAST  
WILL CAUSE SALTWATER INUNDATION, ESPECIALLY IN VULNERABLE COASTAL  
AREAS. THE HIGH TIDES THIS EVENING AND AGAIN ON THURSDAY MORNING  
COULD REACH ADVISORY LEVELS, ESPECIALLY IN SC. THE THURSDAY  
EVENING HIGH TIDE COULD APPROACH WARNING LEVELS. COASTAL FLOOD  
HEADLINES ARE EXPECTED WITH EACH OF THESE TIDE CYCLES.  
 

 
   
CHS WATCHES/WARNINGS/ADVISORIES
 
 
GA...NONE.  
SC...NONE.  
MARINE...NONE.  
 

 
 

 
NEAR TERM...  
SHORT TERM...RJB  
LONG TERM...RJB  
AVIATION...RJB  
MARINE...RJB  
TIDES/COASTAL FLOODING...  
 
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