905  
FXUS62 KCAE 240251  
AFDCAE  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE COLUMBIA SC  
1051 PM EDT SAT JUN 23 2018  
   
SYNOPSIS
 
 
HIGH PRESSURE WILL EXTEND FROM THE ATLANTIC WESTWARD INTO THE  
GULF OF MEXICO THROUGH SUNDAY. NORTH OF THE RIDGE A WEAK TROUGH  
WILL BE IN THE FORECAST AREA. THE PATTERN SUPPORTS HOT CONDITIONS  
WITH SCATTERED THUNDERSTORMS. A BACKDOOR COLD FRONT WILL MOVE  
INTO THE REGION MONDAY.  
 

 
   
NEAR TERM /UNTIL 7 AM SUNDAY MORNING/
 
 
SURFACE HIGH PRESSURE WILL EXTEND FROM THE ATLANTIC WESTWARD  
INTO THE GULF OF MEXICO TONIGHT. NORTH OF THE RIDGE...LEE-SIDE  
TROUGHING WILL BE IN THE FORECAST AREA. CONVECTION HAS ENDED  
ACROSS THE AREA. A WEAK SHORT WAVE EXTENDING FROM CENTRAL TN  
INTO NORTHWEST AL IS FORECAST TO MOVE EAST ACROSS THE AREA LATE  
TONIGHT. THE AIR MASS IS FORECAST TO REMAIN WEAKLY UNSTABLE  
OVERNIGHT. SO...CANNOT COMPLETELY RULE OUT ISOLATED SHOWERS AND  
THUNDERSTORMS OVERNIGHT. HOWEVER, HIGH RESOLUTION MODELS HOLD  
ANY CONVECTION ASSOCIATED WITH THE SHORT WAVE WEST OF THE  
FORECAST AREA. WILL CONTINUE A DRY FORECAST OVERNIGHT. DEBRIS  
CLOUDS OVER THE REGION THIS EVENING SHOULD DIMINISH OVERNIGHT.  
KEPT OVERNIGHT LOWS NEAR CONSENSUS IN THE LOW TO MID 70S.  
 

 
   
SHORT TERM /7 AM SUNDAY MORNING THROUGH MONDAY NIGHT/
 
 
A MID-LEVEL RIDGE WILL BUILD INTO THE AREA SUNDAY AND MONDAY  
WITH 850 MB TEMPS FROM 20 TO 22 DEGREES C. TEMPERATURES WILL BE  
ABOVE NORMAL WITH HIGHS IN THE UPPER 90S TO AROUND 100 DEGREES  
AND LOWS IN THE MID 70S. HEAT INDEX VALUES WILL LIKELY RANGE  
FROM 105 TO 110 WITH THE WARMER VALUES IN THE CSRA WHERE  
SURFACE DEWPOINTS WILL BE HIGHER. A HEAT ADVISORY MAY BE NEEDED  
FOR ONE OR BOTH OF THESE DAYS.  
 
SUBSIDENCE DUE TO WEAK HIGH PRESSURE, WESTERLY DOWNSLOPE FLOW, AND  
A MID-LEVEL CAPPING INVERSION WILL HINDER CONVECTIVE DEVELOPMENT  
ON SUNDAY. THEREFORE, ONLY EXPECT ISOLATED SHOWER AND THUNDERSTORM  
COVERAGE IN THE AFTERNOON. THE BEST CHANCE FOR SCATTERED THUNDERSTORMS  
WILL BE IN THE EVENING AS A SHORTWAVE MOVES THROUGH THE REGION.  
INSTABILITY WILL NATURALLY DIMINISH AFTER SUNSET, BUT BULK SHEAR  
WILL BE AROUND 25 KTS, SO A FEW STRONGER STORMS WILL ALSO BE  
POSSIBLE, WITH DAMAGING WIND THE BIGGEST THREAT.  
 
ON MONDAY, A COLD FRONT WILL MOVE INTO THE REGION. THE FRONT  
WILL LIKELY REMAIN NORTH OF THE FORECAST AREA DURING THE DAY,  
CONTINUING THE TREND OF WELL ABOVE NORMAL HIGH TEMPERATURES,  
ALTHOUGH IT WILL LIKELY BE A FEW DEGREES COOLER THAN SUNDAY. AS  
THE FRONT SAGS SOUTHWARD ON MONDAY EVENING, ANOTHER SHORTWAVE  
WILL ACCOMPANY IT, WITH SCATTERED THUNDERSTORMS THAT COULD  
PERSIST THROUGH MUCH OF THE NIGHT.  
 

 
   
LONG TERM /TUESDAY THROUGH SATURDAY/
 
 
THE FRONT IS EXPECTED TO STALL JUST SOUTH OF THE AREA ON  
TUESDAY, THEN WASH OUT BY WEDNESDAY. DUE TO INCREASED CLOUD  
COVER AND SLIGHTLY COOLER AIR BEHIND THE FRONT, TEMPERATURES  
WILL BE CLOSER TO NORMAL ON TUESDAY AND WEDNESDAY, WITH HIGHS IN  
THE LOW 90S. THERE IS A GOOD CHANCE OF SCATTERED THUNDERSTORMS  
ON TUESDAY, WITH LESSER CHANCES WEDNESDAY AND THURSDAY DUE TO  
HIGH PRESSURE RIDGING, BUT CANNOT RULE OUT DIURNAL CONVECTION.  
ONSHORE FLOW AND MOISTURE WILL INCREASE ON FRIDAY AND SATURDAY,  
SO PRECIPITATION CHANCES WILL ALSO INCREASE GOING INTO NEXT  
WEEKEND. BASICALLY, SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE  
EACH DAY. HOWEVER, EXACTLY WHEN AND WHERE THE MOST POTENT STORMS  
WILL HIT CANNOT BE DETERMINED WITH CERTAINTY AT THESE TIME  
RANGES.  
 

 
   
AVIATION /03Z SUNDAY THROUGH THURSDAY/
 
 
VFR CONDITIONS EXPECTED THROUGH THE 24-HOUR TAF PERIOD.  
 
CONVECTIVE DEBRIS CLOUDINESS REMAINS ACROSS THE REGION WITH  
WSR-88D CURRENTLY ECHO FREE. OVERNIGHT MID AND UPPER CLOUDS WILL  
REMAIN OVER THE REGION WITH LIGHT AND VARIABLE WINDS. POTENTIAL  
FOR FOG REMAINS TOO LOW TO INCLUDE DUE TO DEVELOPMENT OF A LOW  
LEVEL JET AND LIGHT WINDS PROVIDING SOME MIXING. WESTERLY WINDS  
WILL INCREASE TO AROUND 10 KNOTS WITH GUSTS NEAR 20 KNOTS BY  
15Z. ISOLATED TO SCATTERED CONVECTION IS FORECAST DURING PEAK  
HEATING ON SUNDAY. THE THUNDERSTORM CHANCE IS TOO LOW TO INCLUDE  
IN THE TERMINAL FORECASTS AT THIS TIME.  
 
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE EACH DAY IN  
EARLY MORNING FOG AND AFTERNOON AND EVENING THUNDERSTORMS.  
 

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

 
 

 
 
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