758  
FXUS62 KCHS 192343  
AFDCHS  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHARLESTON SC  
743 PM EDT WED SEP 19 2018  
   
SYNOPSIS
 
 
HIGH PRESSURE WILL THEN PREVAIL INTO THE WEEKEND. A COASTAL  
TROUGH OF LOW PRESSURE COULD IMPACT THE AREA EARLY NEXT WEEK,  
WHILE HIGH PRESSURE REMAINS OVER THE ATLANTIC INTO THE MIDDLE  
OF NEXT WEEK.  
 

 
   
NEAR TERM /THROUGH THURSDAY/
 
 
TONIGHT: HIGH PRESSURE WILL CONTINUE TO BUILD IN FROM THE WEST-  
NORTH. WITH HIGH PRESSURE, LIGHT/CALM WINDS, AND CLEAR SKIES,  
WOULD NOT BE SURPRISED TO SEE SOME SHALLOW/PATCHY GROUND FOG,  
ESPECIALLY ACROSS THE NORTHERN 1/3 OF THE FORECAST AREA WHERE  
THE GROUND/SURFACE CONDITIONS ARE A LITTLE MORE MOIST FROM LAST  
WEEKENDS RAIN. OTHERWISE, EXPECT TRANQUIL CONDITIONS WITH LOWS  
FALLING INTO THE UPPER 60S WEST OF I-95, AND LOWER 70S CLOSER TO  
THE COAST. DESPITE THESE TEMPERATURES BEING COOLER THAN THEY  
HAVE BEEN FOR A LONG TIME, THEY WILL STILL BE ABOVE  
CLIMATOLOGICAL NORMALS BY 4 TO 6 DEGREES.  
 

 
   
SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/
 
 
A DEEP LAYER RIDGE WILL BE CENTERED JUST NORTH OF THE REGION ON  
THURSDAY, THEN SHIFT EASTWARD INTO THE ATLANTIC BY LATER FRIDAY AND  
SATURDAY. OVERALL, PRECIP. CHANCES ARE EXPECTED TO BE LOW. THE ONLY  
POPS MENTIONED DURING THE PERIOD ARE ON FRIDAY OVER THE SOUTHERN  
GA REGION, WHERE A BAND OF RELATIVELY HIGHER MOISTURE FROM A WEAK  
BACKDOOR FRONT MEETS SOME ATLANTIC MOISTURE FROM THE EAST. LOW LEVEL  
WINDS WILL BE EASTERLY THROUGH THE PERIOD, GENERALLY 5-10 MPH OVER  
THE LAND, AND 10-15 MPH AT THE COAST. THE EASTERLY FLOW  
WILL ALSO KEEP TEMPERATURES COOLER AT THAT COAST, BUT STILL EXPECT  
GENERALLY AFTERNOON HIGHS IN THE UPPER 80S TO AROUND 90, WHICH IS 4  
TO 6 DEGREES ABOVE NORMAL. HOWEVER, HUMIDITY VALUES WILL BE LOWER  
THAN THEY HAVE BEEN FOR THE PAST SEVERAL WEEKS, WITH INLAND DEWPOINT  
TEMPERATURES MIXING DOWN INTO THE MID TO UPPER 60S EACH AFTERNOON.  
LOWER DEWPOINTS WILL ALLOW NIGHTTIME LOWS TO REACH THE UPPER 60S  
INLAND, BUT STILL LOWER 70S CLOSER TO THE COAST. ALTHOUGH THESE  
LOW TEMPERATURES ARE EXPECTED TO BE COOLER THAN THEY HAVE BEEN FOR  
WEEKS, THEY WILL STILL BE ABOVE SEASONAL NORMAL LEVELS.  
 

 
   
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/
 
 
THE LARGE/EXPANSIVE RIDGE OF HIGH PRESSURE OVER THE SOUTHEAST UNITED  
STATES WILL BECOME MORE CENTERED OVER THE WESTERN ATLANTIC BY EARLY  
NEXT WEEK WHILE A FRONT APPROACHES FROM THE NORTH, BUT LIKELY STALLS  
WELL NORTH/NORTHWEST OF THE REGION. MOST SHOWER/THUNDERSTORM  
ACTIVITY SHOULD REMAIN OFFSHORE LATE WEEKEND INTO EARLY NEXT WEEK.  
HOWEVER, SOME MODELS CONTINUE TO FAVOR SHOWERS AND/OR THUNDERSTORMS  
OVER COASTAL GEORGIA WHERE MID-LVL ENERGY PROVIDES SUFFICIENT  
FORCING AND AN ONSHORE WIND ADVECTS MOISTURE OVER LAND. THERE COULD  
BE SOME ENHANCEMENT TO PRECIP COVERAGE EARLY IN THE WEEK AS A  
COASTAL TROUGH SHIFTS ONSHORE AND PWATS APPROACH 2.0 INCHES OVER THE  
AREA. THEREAFTER, A PERSISTENT ONSHORE FLOW ALONG THE SOUTHWEST EDGE  
OF THE ATLANTIC HIGH COULD PRODUCE CHANCES OF SHOWERS/THUNDERSTORMS  
INTO MID WEEK WITH PRECIP COVERAGE PEAKING DURING MAXIMUM SFC  
HEATING EACH DAY. HIGH TEMPS WILL GENERALLY RANGE IN THE MID/UPPER  
80S ACROSS SOUTHEAST SOUTH CAROLINA THIS WEEKEND AND EARLY NEXT  
WEEK. SOME AREAS COULD TOUCH 90 DEGREES ACROSS SOUTHEAST GEORGIA.  
OVERNIGHT LOWS SHOULD RANGE IN THE UPPER 60S TO AROUND 70 DEGREES  
INLAND TO MID/UPPER 70S ALONG THE COAST.  
 

 
   
AVIATION /00Z THURSDAY THROUGH MONDAY/
 
 
SOME MODEL GUIDANCE INDICATING THE POTENTIAL FOR PATCHY  
SHALLOW/GROUND FOG. GIVEN THE RIDGE BUILDING IN, CLEAR SKIES AND  
LIGHT WINDS, IT SEEMS REASONABLE. HAVE INTRODUCED BCFG FOR NOW,  
WITH VSBYS STILL REMAINING VFR. FEEL CONDITIONS ARE SLIGHTLY  
MORE FAVORABLE FOR CHS TO GET SHALLOW FOG VS SAV, BUT GIVEN  
UNCERTAINTY, PUT IT IN SAV TAF TOO.  
 
EXTENDED AVIATION OUTLOOK: VFR CONDITIONS ARE EXPECTED TO PREVAIL  
AT BOTH KCHS AND KSAV TERMINALS THROUGH SUNDAY. DEEP LAYER  
MOISTURE MAY BEGIN TO RETURN BY MONDAY, WHICH COULD INCREASE THE  
CHANCES FOR SHOWERS/THUNDERSTORMS AND THE THREAT FOR BRIEF  
FLIGHT RESTRICTIONS.  
 

 
   
MARINE
 
 
TONIGHT: HIGH PRESSURE WILL CONTINUE TO BUILD SOUTH INTO THE COASTAL  
WATERS. VARIABLE WINDS GENERALLY 5 KNOTS OR LESS WILL RESULT WITH  
SEAS AVERAGING 1-2 FEET, 3 FEET BEYOND 30 NM.  
 
THURSDAY THROUGH MONDAY: NO HIGHLIGHTS ARE EXPECTED AT THIS TIME  
THROUGH THE PERIOD. DEEP HIGH PRESSURE WILL REMAIN CENTERED  
GENERALLY NORTH OF THE WATERS THROUGH THE PERIOD, WITH EASTERLY  
WINDS OF 15 KNOTS OR LESS AND SEAS OF 2 TO 4 FEET. A WEAK  
BACKDOOR FRONT IS INDICATED BY THE MODELS TO MOVE IN FROM THE  
NORTH THURSDAY NIGHT AND EARLY FRIDAY. THIS FEATURE MAY INCREASE  
THE PRESSURE GRADIENT ENOUGH TO PUSH WINDS UP TO 15 TO 20 KNOTS  
THROUGH FIRST PART OF FRIDAY, BEFORE COMING BACK DOWN AGAIN. NO  
SIGNIFICANT CHANCES FOR SHOWERS/THUNDERSTORMS UNTIL VERY LATE  
IN THE WEEKEND AND EARLY NEXT WEEK, WHEN BETTER DEEP LAYER  
MOISTURE MOVES INTO THE AREA.  
 

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

 
 

 
NEAR TERM...JMC/RFM  
SHORT TERM...RFM  
LONG TERM...DPB  
AVIATION...JMC/RFM  
MARINE...JMC/RFM  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab SC Page
The Nexlab GA Page Main Text Page