501  
FXUS62 KCAE 181706  
AFDCAE  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE COLUMBIA SC  
106 PM EDT THU JUL 18 2019  
   
SYNOPSIS
 
 
AN UPPER AND SURFACE TROUGH WILL MOVE INTO THE REGION TODAY AND  
PROVIDE BETTER CHANCES OF SCATTERED AFTERNOON AND EVENING  
THUNDERSTORMS TODAY AND FRIDAY. A SURFACE TROUGH WILL CONTINUE  
TO SUPPORT SCATTERED AFTERNOON THUNDERSTORMS THROUGH THE WEEKEND.  
AN UPPER-LEVEL TROUGH WILL DIG INTO THE EASTERN US EARLY NEXT  
WEEK WITH A FRONTAL BOUNDARY ENTERING THE REGION MID-WEEK.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
UPPER LEVEL TROUGH OVER THE CAROLINAS THIS AFTERNOON AND  
OVERNIGHT AS RIDGE HAS SHIFTED SLIGHTLY SOUTH OF THE AREA.  
WITH STRONG INSOLATION, RELATIVELY STEEP LOW TO MID LEVEL LAPSE  
RATES RESULTING IN MODERATE INSTABILITY AND PERHAPS STRONG LATE  
IN THE AFTERNOON. SB CAPE AROUND 2500 J/KG. SOME MID LEVEL DRY  
AIR NOTED ON SOUNDINGS AND RELATIVELY HIGH LFC WITH INVERTED V  
SUGGEST SOME POTENTIAL FOR STRONG GUSTY WINDS. SO CAN'T RULE OUT  
AN ISOLATED SEVERE PULSE STORM. WITH THE POTENTIAL FOR SHORT  
WAVE ENERGY, ENHANCED LIFT MAY RESULT IN STRONGER POTENTIAL FOR  
CONVECTION. THE LATEST HIGH RESOLUTION MODELS DEVELOP CONVECTION  
IN THE PIEDMONT AND MOVE SOUTHEAST ACROSS THE MIDLANDS (LIKELY  
SCATTERED) AND POSSIBLY INCREASE TOWARD THE COASTAL PLAIN.  
PRECIPITABLE WATER NEAR 1.89 INCHES SO SOME HEAVY RAIN POSSIBLE  
BUT STORM MOVEMENT SHOULD LIMIT AMOUNTS. MAX TEMPS IN THE MID TO  
UPPER 90S WITH HEAT INDEX AROUND 107 DEGREES. MUGGY TONIGHT  
WITH LOWS IN THE MID 70S.  
 

 
   
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/
 
 
TEMPERATURES WILL AGAIN BE IN THE MID TO UPPER 90S WITH MAXIMUM HEAT  
INDEX VALUES FROM 100 TO AROUND 105. EXPECT SCATTERED THUNDERSTORMS  
EACH AFTERNOON AND EVENING.  
 
AN UPPER RIDGE WILL BE CENTERED NORTH OF THE FORECAST AREA FRIDAY  
WITH A WEAK INVERTED TROUGH TO OUR SOUTH. AT THE SURFACE, A LEE-SIDE  
TROUGH WILL PROVIDE CONVERGENCE FOR CONVECTIVE DEVELOPMENT. PWAT  
VALUES WILL REMAIN HIGH AS ABUNDANT MOISTURE RESIDES OVER THE  
REGION WITH VALUES AROUND 2 INCHES. ALL THESE FACTORS SUPPORT  
SCATTERED THUNDERSTORM DEVELOPMENT AND A HIGH CHANCE (40%-50%)  
OF RAIN. RAIN CHANCES ARE NOT AS HIGH ON SATURDAY AS THE UPPER  
TROUGH FLATTENS OUT WITH LITTLE VORTICITY ADVECTION INTO THE  
REGION. SEVERE WEATHER POTENTIAL EACH DAY IS LOW GIVEN THE TALL,  
SKINNY CAPE PROFILES AND LITTLE DRY AIR ALOFT TO PROMOTE STRONG  
DOWNDRAFTS. WITH LESS CONVECTIVE COVERAGE SATURDAY IT MAY BE A  
SLIGHTLY WARMER THAN FRIDAY WITH FEWER THUNDERSTORMS TO DISTURB  
DIURNAL HEATING. OVERNIGHT LOWS WILL CONTINUE TO BE WARMER THAN  
NORMAL WITH VALUES IN THE MID 70S EACH NIGHT.  
 

 
   
LONG TERM /SUNDAY THROUGH THURSDAY/
 
 
LATE THIS WEEKEND INTO EARLY NEXT WEEK, AN UPPER RIDGE PREVAILS OVER  
THE FORECAST AREA WITH PWAT WATER VALUES DROPPING TO AROUND  
1.5-1.8 INCHES. THE PRESENCE OF A LEE-SIDE SURFACE TROUGH WILL  
CONTINUE TO PROMOTE SCATTERED DIURNAL CONVECTION.  
 
MIDWEEK, A DEEP UPPER LEVEL TROUGH IS FORECAST TO DIG INTO THE  
EASTERN US. THIS WILL PUSH A COLD FRONT INTO THE SOUTHEAST  
BEFORE STALLING NEAR THE FORECAST AREA. THIS WILL SUPPORT COOLER  
DAYTIME TEMPERATURES AND HIGHER RAINFALL CHANCES. THE HIGHEST  
CONVECTIVE ACTIVITY WILL DEPEND ON THE LOCATION AND TIMING OF  
THE FRONT WHICH WILL BE BETTER KNOWN OVER THE NEXT SEVERAL DAYS.  
AT THIS TIME, RAINFALL APPEARS LIKELY ON TUESDAY AND WEDNESDAY  
FOR AT LEAST PORTIONS OF THE AREA. THE ECMWF HAS LEANED CLOSER  
TO THE GFS TOWARDS THE END OF THE EXTENDED, KEEPING THE STALLED  
UPPER LEVEL TROUGH OVER THE EASTERN US FOR A LONGER PERIOD OF  
TIME. HIGH TEMPERATURES WILL REMAIN ABOVE NORMAL SUNDAY AND  
MONDAY WITH HIGHS IN THE MID 90S BUT THEN FALL TO NEAR NORMAL  
WITH INCREASED CLOUDS AND PRECIPITATION ON TUESDAY AND WEDNESDAY  
WITH HIGHS IN THE MID TO UPPER 80S.  
 

 
   
AVIATION /18Z THURSDAY THROUGH TUESDAY/
 
 
UPPER AND SURFACE TROUGH, DIURNAL HEATING, AND SUFFICIENT ATMOSPHERIC  
MOISTURE EXPECTED TO RESULT IN INCREASED CONVECTIVE COVERAGE  
THIS AFTERNOON/EVENING. HIGH RESOLUTION MODELS SUGGEST SCATTERED  
COVERAGE. ISOLATED SEVERE PULSE STORM POSSIBLE. SATELLITE  
SHOWING CUMULUS DEVELOPING NORTHWEST OF CAE AT 16Z WITH  
THUNDERSTORMS IN NORTH GA MOVING SOUTHEAST. WILL ADD TEMPO  
GROUPS TO TERMINALS 20-24Z. CONVECTION WILL DIMINISH MID TO LATE  
EVENING WITH MAINLY MID LEVEL CEILINGS OVERNIGHT ALTHOUGH THERE  
COULD BE SOME STRATUS LATE. MVFR FOG POSSIBLE AT FOG PRONE SITES  
AGS/OGB.  
 
EXTENDED AVIATION OUTLOOK...SCATTERED AFTERNOON/EVENING  
THUNDERSTORMS AND SOME POTENTIAL FOR LATE NIGHT/EARLY MORNING  
STRATUS/FOG THROUGH THE PERIOD.  
 

 
   
CAE WATCHES/WARNINGS/ADVISORIES
 
 
GA...NONE.  
SC...NONE.  
 

 
 

 
 
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