727  
FXUS62 KCHS 172005  
AFDCHS  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHARLESTON SC  
405 PM EDT TUE JUL 17 2018  
   
SYNOPSIS
 
 
A COLD FRONT WILL APPROACH THE REGION TONIGHT, THEN STALL OVER  
OR NEARBY OUR AREA THROUGH THURSDAY. THE FRONT WILL LIKELY LIFT  
NORTH ON FRIDAY. ANOTHER COLD FRONT MAY APPROACH FROM THE  
NORTHWEST LATER THIS WEEKEND.  
 

 
   
NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/
 
 
SCATTERED TO WIDESPREAD SHOWERS AND STORMS ARE EXPECTED THROUGH  
EARLY EVENING AS BEFORE TAPERING OFF OVERNIGHT AND SHIFTING  
MAINLY OFFSHORE AHEAD OF AN APPROACHING COLD FRONT. CANNOT RULE  
OUT A SEVERE STORM WITH DAMAGING WINDS FROM WET MICROBURSTS BUT  
THE MAIN IMPACTS WILL LIKELY BE FREQUENT LIGHTNING AND HEAVY  
RAINFALL. COULD SEE SOME FOG DEVELOP LATE TONIGHT, MAINLY  
FARTHER INLAND. LOW TEMPERATURES SHOULD MAINLY BE IN THE MID TO  
UPPER 70S.  
 

 
   
SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/
 
 
AN UNSETTLED WEATHER PATTERN IS EXPECTED THROUGH THE REST OF THE  
WORK WEEK. A BROAD UPPER TROUGH WILL BE OVER THE EASTERN U.S. ON  
WEDNESDAY, WHICH WILL HELP DRAG A WEAK SURFACE COLD FRONT INTO THE  
REGION. THIS FRONT WILL STALL OVER THE SOUTHERN AREA ON THURSDAY. BY  
FRIDAY, THE FRONT WILL LIKELY SHIFT NORTHWARD AS ANOTHER UPPER  
TROUGH DIGS IN FROM THE GREAT LAKES STATES, WHICH HELPS TO DEVELOP A  
WEAK SURFACE LOW SOUTHWEST TO NORTHEAST ALONG THE FRONT.  
 
THE BIGGEST CONCERN FOR THIS PERIOD CONTINUES TO BE THE POTENTIAL  
FOR LOCALLY HEAVY RAINFALL, GIVEN PWS IN THE 2-2.4 INCH RANGE FOR  
THE PERIOD AND RELATIVELY WEAK STEERING FLOW. MODELS CONTINUE TO  
SHOW BETTER DOWNDRAFT CAPE FOR WEDNESDAY, WHICH COULD HELP SUPPORT  
ISOLATED STRONG TO LOW END SEVERE STORMS IF THERE IS ENOUGH HEATING.  
 
HARD TO PIN DOWN LOCATION FOR HIGHEST POPS FOR THIS PERIOD, SINCE IT  
DEPENDS ON THE LOCATION OF THE SURFACE FRONT AND ANY WEAK UPPER  
SHORT WAVES TO PROVIDE FORCING. HAVE KEPT HIGH END CHANCE TO LOW END  
LIKELY POPS FOR MUCH OF THE AREA ON WEDNESDAY. THURSDAY, IF THE  
FRONT SHIFTS SOUTHWARD, THE HIGHEST POPS WILL ALSO LIKELY SHIFT  
SOUTHWARD INTO THE SOUTHERN AREA. BY FRIDAY, GLOBAL MODELS SEEM TO  
BE MORE AGGRESSIVE WITH DEVELOPING A WEAK SURFACE WAVE ALONG THE  
FRONT AS IT MOVES BACK ACROSS THE REGION. THE NAM IS NOT AS  
AGGRESSIVE WITH THIS WAVE AND KEEPS BEST MOISTURE FURTHER SOUTH.  
GIVEN UNCERTAINTY, WENT WITH HIGH END CHANCE TO LOW END LIKELY POPS  
MOST OF THE AREA.  
 
HIGH TEMPERATURES WILL LIKELY BE NEAR TO A LITTLE BELOW NORMAL GIVEN  
HIGHER CLOUD COVER AND BETTER POTENTIAL FOR SHOWERS AND  
THUNDERSTORMS EACH AFTERNOON. HIGHS GENERALLY IN THE MID TO UPPER  
80S, EXCEPT SOME LOWER 90S POSSIBLE IN AREAS THAT GET MORE SUN. LOWS  
IN THE LOWER TO MID 70S.  
 

 
   
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/
 
 
A WARM FRONT WILL BE NORTH OF OUR AREA FRIDAY NIGHT. A TROUGH IS  
EXPECTED TO DEVELOP INLAND OVER THE WEEKEND WHILE ANOTHER COLD FRONT  
SLOWLY APPROACHES. THE END RESULT WILL BE A RAINY WEATHER  
PATTERN.  
 

 
   
AVIATION /19Z TUESDAY THROUGH SUNDAY/
 
 
MAINLY VFR OUTSIDE SHOWERS/TSTMS WHICH ARE MOST LIKELY THROUGH  
AROUND 00Z AT KCHS/KSAV AND THEN AGAIN WEDNESDAY AFTERNOON,  
ESPECIALLY AT KCHS. MVFR CIGS CANNOT BE RULED OUT LATE TONIGHT  
BUT CONFIDENCE IS LOW AT THIS TIME.  
 
EXTENDED AVIATION OUTLOOK: A WEAK SURFACE FRONT WILL BE AROUND  
THE REGION WEDNESDAY THROUGH FRIDAY, WHICH WILL RESULT IN BETTER  
CHANCES FOR CONVECTION, MAINLY DURING THE AFTERNOON PERIODS.  
THEREFORE, BRIEF FLIGHT RESTRICTIONS DUE TO THUNDERSTORMS WILL  
BE POSSIBLE BOTH TERMINALS. SCATTERED MAINLY AFTERNOON SHOWERS  
WITH THE POTENTIAL FOR FLIGHT RESTRICTIONS THROUGH THE FIRST  
HALF THE WEEKEND. BY LATER IN THE WEEKEND/SUNDAY, A COLD FRONT  
MAY MOVE THROUGH WITH THE POTENTIAL FOR LOWER CHANCES FOR  
CONVECTION INTO EARLY NEXT WEEK.  
 

 
   
MARINE
 
 
TONIGHT: AN APPROACHING COLD FRONT WILL LEAD TO ELEVATED  
SOUTHWEST WINDS, ALTHOUGH MAINLY STAYING BELOW ADVISORY LEVELS.  
SEAS WILL ALSO BE ELEVATED AS A RESULT BUT GENERALLY STAY LESS  
THAN 4 FEET. STORMS WILL IMPACT THE WATERS AT TIMES WITH HEAVY  
RAIN, LIGHTNING AND GUSTY WINDS.  
 
WEDNESDAY THROUGH SUNDAY: NO HIGHLIGHTS EXPECTED THROUGH THE  
PERIOD. GENERALLY WINDS OF 15 KNOTS OR LESS AND SEAS 4 FEET OR  
LESS EACH DAY. A WEAK FRONT WILL BE OVER THE WATERS THROUGH THE  
REST OF THE WORK WEEK AND EARLY THIS WEEKEND. THIS WILL RESULT  
IN HIGHER CHANCES FOR SHOWERS/THUNDERSTORMS.  
 

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

 
 

 
NEAR TERM...RJB  
SHORT TERM...RFM  
LONG TERM...  
AVIATION...RFM/RJB  
MARINE...RFM/RJB  
 
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