649  
FXUS62 KCAE 021817  
AFDCAE  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE COLUMBIA SC  
117 PM EST FRI DEC 2 2016  
   
SYNOPSIS
 
 
DRY CONDITIONS WILL PERSIST THROUGH SATURDAY ASSOCIATED WITH  
RIDGING. A LOW PRESSURE SYSTEM WILL TRACK FROM THE WESTERN GULF  
COAST REGION NORTHEASTWARD INTO THE OHIO RIVER VALLEY EARLY NEXT  
WEEK. THE ASSOCIATED WARM FRONT WILL LIKELY REMAIN SOUTH OF THE  
FORECAST AREA THROUGH MONDAY. THE WARM FRONT MAY LIFT NORTH  
AND INTO THE FORECAST AREA TUESDAY AHEAD OF A COLD FRONT.  
THE COLD FRONT WILL LIKELY BE OFF THE COAST LATE TUESDAY.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
SURFACE HIGH PRESSURE OVER THE DEEP SOUTH WILL CONTINUE TO RIDGE  
INTO THE AREA. LIGHT N/NW SURFACE WINDS CURRENTLY OBSERVED WILL  
BECOME INCREASINGLY WESTERLY AS A LEE-SIDE TROUGH DEVELOPS THIS  
AFTERNOON. NEAR ZONAL UPPER FLOW AND DRY AIR WILL HOLD CLEAR SKIES  
ACROSS THE REGION TODAY. NW 850 MB WINDS INDICATE DOWNSLOPE FLOW  
OVER THE AREA WHICH MAY LEAD TO WARMER AFTERNOON TEMPERATURES THAN  
GUIDANCE SUGGESTS. AFTERNOON HIGHS ARE EXPECTED TO BE NEAR NORMAL  
IN THE UPPER 50S TO LOWER 60S.  
 
MODELS HAVE SHOWN MORE CLOUD COVER IN RECENT RUNS, PARTICULARLY  
EARLY SATURDAY MORNING. THIS AGREES WITH CURRENT WATER VAPOR  
IMAGERY SHOWING UPPER LEVEL MOISTURE MOVING INTO THE DEEP SOUTH.  
THIS WOULD LIMIT RADIATIONAL COOLING, AT LEAST FOR THE LATER  
PORTION OF THE NIGHT. THEREFORE FAVORED THE WARMER TEMPERATURE  
GUIDANCE. ADDITIONALLY A 20 TO 25 KT LLJ MAY PROMOTE LOW LEVEL  
MIXING. LOWS WILL GENERALLY BE IN THE MID TO UPPER 30S BUT DEPENDING  
ON THE LOCATION/THICKNESS OF CLOUD COVER COULD BE NEAR FREEZING  
IN SOME AREAS.  
 

 
   
SHORT TERM /SATURDAY THROUGH SUNDAY/
 
 
DRY WEATHER WILL CONTINUE THROUGH SATURDAY NIGHT WITH SURFACE  
HIGH PRESSURE RIDGING INTO THE AREA. UPPER-LEVEL MOISTURE WILL  
ADVECT INTO THE REGION SATURDAY AND SATURDAY NIGHT AHEAD OF A  
SOUTHERN STREAM SYSTEM OVER THE SOUTHWESTERN PART OF THE COUNTRY.  
THE MODELS INDICATE SIGNIFICANT ISENTROPIC LIFT DEVELOPING SUNDAY.  
LEANED TOWARD THE HIGHER POPS SUNDAY BASED ON THE FAST SOUTHERN  
STREAM FLOW. FORECASTED POPS BECOMING LIKELY DURING THE  
AFTERNOON. FOLLOWED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE  
FORECAST SATURDAY AND SATURDAY NIGHT. THE INCREASED CLOUDS WILL  
HELP HOLD UP TEMPERATURES BECAUSE OF DIMINISHED NET RADIATIONAL  
COOLING SATURDAY NIGHT AND IT SHOULD NOT BE A COOL AS THE PREVIOUS  
NIGHT. LEANED TOWARD THE LOWER MAXIMUM TEMPERATURE GUIDANCE SUNDAY  
BECAUSE OF A COOL START AND EXPECTED CLOUDINESS.  
 

 
   
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/
 
 
THE GFS AND ECMWF KEEP THE WARM FRONT SOUTH OF THE FORECAST AREA  
THROUGH MONDAY. ISENTROPIC LIFT SUPPORTS HIGH POPS. THE HIGH  
TEMPERATURE GUIDANCE IS LIKELY TOO HIGH BECAUSE OF A WEDGE  
PATTERN. THE WARM FRONT MAY MOVE INTO THE FORECAST AREA TUESDAY  
BUT THIS IS QUESTIONABLE BECAUSE THE COOL WEDGE MAY LINGER.  
THE GFS AND ECMWF HAVE BEEN CONSISTENT DEPICTING A 50-KNOT H85  
JET. THE COMBINATION OF THE JET AND COOLING ASSOCIATED WITH THE  
H5 TROUGH MAY HELP SUPPORT THUNDERSTORMS AND WE HAVE INCLUDED  
ISOLATED STORMS IN THE FORECAST. SEVERE THUNDERSTORMS COULD  
POSSIBLY OCCUR IF THE WARM FRONT GETS INTO THE FORECAST AREA AND  
SURFACE-BASED INSTABILITY DEVELOPS. THE GFS AND ECMWF HAVE NOT  
BEEN CONSISTENT WITH A FRONTAL SYSTEM THURSDAY WITH THE ECMWF  
SHOWING MORE MOISTURE. USED AN AVERAGE FOR THE POP FORECAST.  
 

 
   
AVIATION /18Z FRIDAY THROUGH WEDNESDAY/
 
 
VFR CONDITIONS LIKELY THROUGH THE 24 HOUR TAF PERIOD.  
 
DRY HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE REGION. WINDS  
WILL GENERALLY BE OUT OF THE N/NW BUT MAY BE LIGHT AND VARIABLE  
FOR MANY SITES THIS AFTERNOON. WIND DIRECTION WILL BECOME  
INCREASINGLY WESTERLY THROUGH THE AFTERNOON AS A LEE-SIDE TROUGH  
DEVELOPS. EXPECT LIGHT AND VARIABLE WINDS OVERNIGHT WITH THE  
EXCEPTION OF DNL WHICH MAY KEEP WINDS UP OVERNIGHT DUE TO A 20 TO  
25 KT LLJ. SKIES WILL BE CLEAR THROUGH THE DAY WITH A FEW HIGH  
CLOUDS MOVING OVER THE AREA TONIGHT AND EARLY SATURDAY. FOG IS NOT  
EXPECTED.  
 
THE INVERSION WILL BREAK AROUND 15Z SATURDAY WITH NE WINDS AROUND  
5 KTS. SCATTERED TO BROKEN HIGH CLOUDS WILL BE PRESENT AS UPPER  
LEVEL MOISTURE MOVES ACROSS THE REGION.  
 
EXTENDED AVIATION OUTLOOK...A SYSTEM WILL BRING PRECIPITATION AND  
PERIODS OF ASSOCIATED RESTRICTIONS SUNDAY THROUGH TUESDAY.  
 

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

 
 

 
 
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