478  
FXUS62 KCHS 142018  
AFDCHS  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHARLESTON SC  
318 PM EST THU DEC 14 2017  
   
SYNOPSIS
 
 
A DRY COLD FRONT WILL PUSH THROUGH FRIDAY NIGHT BEFORE HIGH  
PRESSURE RETURNS SATURDAY AND SUNDAY. ANOTHER COLD FRONT WILL  
ARRIVE MONDAY INTO TUESDAY BEFORE SHIFTING OFFSHORE ON  
WEDNESDAY. HIGH PRESSURE SHOULD THEN PERSIST INTO LATE WEEK.  
 

 
   
NEAR TERM /UNTIL 6 AM FRIDAY MORNING/
 
 
AS OF 315 PM: BASED ON TRENDS SEEN IN RECENT GOES-16 IMAGES,  
HIGH CLOUDS WILL INCREASE IN COVERAGE AND DENSITY THROUGH  
TONIGHT ACROSS THE FORECAST AREA. THE HIGH MOISTURE IS SOURCED  
FROM A CLOSED MID LEVEL LOW CENTERED OVER THE BAJA REGION OF  
MEXICO. NEAR TERM GUIDANCE INDICATES THAT A SURFACE WAVE WILL  
MOVE FROM THE FOOTHILLS OF THE CAROLINAS EAST ALONG THE NC/SC  
LINE TONIGHT. A WEAK COLD FRONT ASSOCIATED WITH THE WAVE SHOULD  
REMAIN GENERALLY WEST OF THE FORECAST AREA THROUGH TONIGHT. THE  
PRESSURE GRADIENT IN PROXIMITY TO THE WAVE AND FRONT IS EXPECTED  
TO BE LIMITED TO A SINGLE MB. LIGHT WINDS SHOULD FAVOR A SW  
DIRECTION THROUGH MOST OF THE NIGHT, BECOMING CALM DURING THE  
PRE DAWN HOURS. LOW TEMPERATURES ARE FORECAST TO RANGE AROUND 40  
DEGREES.  
 

 
   
SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/
 
 
PRETTY HIGH CONFIDENCE THIS PERIOD WITH NO SIGNIFICANT WEATHER  
EXPECTED. SURFACE HIGH PRESSURE WILL PREVAIL, ALTHOUGH A DRY COLD  
FRONT WILL MOVE THROUGH FRIDAY NIGHT. CAN'T COMPLETELY RULE OUT A  
SHOWER FRIDAY AHEAD OF THE FRONT BUT IT LOOKS LIKE DEEP LOW-LEVEL  
DRY AIR WILL BE IN PLACE SO WE MAINTAINED A DRY FORECAST. ALSO COULD  
SEE A FEW SHOWERS LATER SUNDAY AS MOISTURE AND LOW-LEVEL ISENTROPIC  
ASCENT INCREASE. HIGH TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL  
FRIDAY AND SUNDAY AND NEAR NORMAL SATURDAY. LOW TEMPERATURES WILL  
GENERALLY BE NEAR NORMAL, WHICH MEANS NEAR FREEZING WELL INLAND  
SATURDAY AND SUNDAY MORNING.  
 

 
   
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/
 
 
CLOUD COVER SHOULD EXPAND OVER THE SOUTHEAST SUNDAY NIGHT WITH  
INCREASING MOISTURE AND ISENTROPIC ASCENT OCCURRING WELL AHEAD OF A  
COLD FRONT APPROACHING THE AREA. CHANCES OF SHOWERS SHOULD ARRIVE  
LATE SUNDAY NIGHT AND INCREASE IN COVERAGE THROUGH MONDAY AS A PLUME  
OF MOISTURE CHARACTERIZED BY PWATS NEAR 1.75-2.0 INCHES ADVECTS OVER  
THE SOUTHEAST ALONG/AHEAD OF THE SLOWLY APPROACHING FRONT. TEMPS  
COULD PEAK INTO THE UPPER 60S TO AROUND 70 DEGREES ON MONDAY DESPITE  
CLOUDS AND INCREASING SHOWER COVERAGE, MAINLY DUE TO THE STRENGTH  
AND POSITION OF THE MID/UPPER LVL RIDGE OF HIGH PRESSURE TO THE  
SOUTHEAST. TEMPS WILL REMAIN MILD MONDAY NIGHT AND TUESDAY WHILE MID-  
LVL ENERGY CONTINUES TO TRAVERSE THE SOUTHEAST BEFORE THE MAIN MID-  
LVL TROUGH AXIS AND ASSOCIATED COLD FRONT SHIFT OVER THE AREA LATE  
TUESDAY INTO EARLY WEDNESDAY. FOR THIS REASON, AT LEAST CHANCES OF  
SHOWERS WILL BE POSSIBLE MONDAY NIGHT INTO EARLY WEDNESDAY BEFORE  
DRY HIGH PRESSURE RETURNS BEHIND THE COLD FRONT SHIFTING OFFSHORE.  
 

 
   
AVIATION /20Z THURSDAY THROUGH TUESDAY/
 
 
VFR.  
 
EXTENDED AVIATION OUTLOOK: NO SIGNIFICANT CONCERNS THROUGH SUNDAY  
BUT RESTRICTIONS ARE LIKELY THEREAFTER INTO AT LEAST EARLY TUESDAY  
AS DEEPENING MOISTURE INCREASES THE RISK FOR LOW CLOUDS AND RAIN  
WITH A COLD FRONT.  
 

 
   
MARINE
 
 
TONIGHT: NEAR TERM GUIDANCE INDICATES THAT A SURFACE WAVE WILL  
MOVE FROM THE FOOTHILLS OF THE CAROLINAS EAST ALONG THE NC/SC  
LINE TONIGHT. A WEAK COLD FRONT ASSOCIATED WITH THE WAVE SHOULD  
REMAIN GENERALLY WEST OF THE FORECAST AREA THROUGH TONIGHT. THE  
PRESSURE GRADIENT IN PROXIMITY TO THE WAVE AND FRONT IS EXPECTED  
TO BE LIMITED TO A SINGLE MB. WINDS SHOULD FAVOR A WSW DIRECTION  
NEAR 10 KTS. SEAS ARE FORECAST TO RANGE BETWEEN 1-2 FEET.  
 
FRIDAY THROUGH TUESDAY: EXPECT A BIT OF A WIND/SEA INCREASE BEHIND A  
COLD FRONT MOVING THROUGH FRIDAY NIGHT BUT CONDITIONS SHOULD REMAIN  
BELOW ADVISORY LEVELS. NO SIGNIFICANT CONCERNS THEREAFTER WITH HIGH  
PRESSURE BUILDING IN THROUGH SUNDAY, THEN CONDITIONS WILL GO  
DOWNHILL A BIT AS A COLD FRONT APPROACHES THE AREA.  
 

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

 
 

 
NEAR TERM...NED  
SHORT TERM...RJB  
LONG TERM...  
AVIATION...NED/RJB  
MARINE...NED/RJB  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab SC Page
The Nexlab GA Page Main Text Page