458  
FXUS62 KCAE 162308  
AFDCAE  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE COLUMBIA SC  
608 PM EST WED JAN 16 2019  
   
SYNOPSIS
 
 
DRY HIGH PRESSURE WILL BE OVER THE AREA TONIGHT WITH LOWS IN THE  
UPPER 20S TO LOW 30S. A LOW PRESSURE SYSTEM WILL CROSS THE  
REGION THURSDAY NIGHT AND FRIDAY, FOLLOWED BY A MORE POWERFUL  
STORM SYSTEM OVER THE WEEKEND AND MUCH COLDER TEMPERATURES EARLY  
NEXT WEEK.  
 

 
   
NEAR TERM /UNTIL 6 AM THURSDAY MORNING/
 
 
HIGH PRESSURE OVER THE FORECAST AREA WILL LEAD TO LIGHT OR CALM  
WINDS OVERNIGHT. MODELS HAVE BEEN SUGGESTING HIGH CLOUDS WILL  
MOVE OVER THE FORECAST AREA EARLY THURSDAY MORNING INTERRUPTING  
IDEAL RADIATIONAL COOLING CONDITIONS. ALTHOUGH RECENT RUNS HAVE  
SHOWN A TREND IN DELAYING SIGNIFICANT CLOUD COVER UNTIL AFTER  
SUNRISE. THEREFORE LOWS TONIGHT WILL DEPEND ON THE TIMING OF  
THE HIGH CLOUDS MOVING OVER A WEAK UPPER RIDGE. THE TREND  
TOWARDS THE LATER ARRIVAL OF THE CLOUDS SUPPORTS A LONGER  
DURATION OF RADIATIONAL COOLING AND COOLER TEMPERATURES. IN  
ADDITION THE ECMWF VERIFIED BETTER FOR YESTERDAY'S LOWS UNDER  
SIMILAR CONDITIONS. THEREFORE WE EXPECT LOWS ON THE COOLER END  
OF THE TEMPERATURE GUIDANCE SPECTRUM WITH LOWS FROM THE UPPER  
20S TO LOW 30S. PATCHY FOG DEVELOPMENT IS EXPECTED, MAINLY ALONG  
AREA RIVERS AND OTHER FOG PRONE SITES.  
 

 
   
SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/
 
 
A FAST MOVING UPPER TROUGH WILL MOVE ACROSS THE OHIO VALLEY  
THURSDAY AND INTO THE MID-ATLANTIC BY THURSDAY NIGHT. THE MAIN  
UPPER LIFT ASSOCIATED WITH THE SHORTWAVE REMAINS WELL OFF TO THE  
NORTH OF THE AREA, AND DEEPER MOISTURE REMAINS LIMITED WITH  
THIS SYSTEM AS IT PUSHES EAST OF THE APPALACHIANS AND INTO THE  
CWA. STILL ONLY EXPECTING MAINLY ISOLATED TO SCATTERED SHOWERS  
WITH THIS FAST MOVING SYSTEM. RAINFALL TOTALS EXPECTED TO BE  
LIGHT.  
 
BEHIND THIS SYSTEM ON FRIDAY, SHORTWAVE RIDGING WILL BUILD OVER  
THE FORECAST AREA, KEEPING THE AREA DRY FROM FRIDAY THROUGH  
THE MAJORITY OF FRIDAY NIGHT. HIGHS ON THURSDAY WILL BE NEAR  
NORMAL IN THE MID 50S TO LOWER 60S. FRIDAY SHOULD SEE WARMING  
TEMPERATURES INTO THE 60S AS WARM ADVECTION TRIES TO RETURN.  
 

 
   
LONG TERM /SATURDAY THROUGH WEDNESDAY/
 
 
BY SATURDAY MORNING, A STRONGER SHORTWAVE WILL BE MOVING INTO  
THE AREA FROM THE WEST. BOTH THE GFS AND ECMWF SHOWING BOTH  
STRONG WARM ADVECTION AND MOISTURE ADVECTION INTO THE REGION.  
SURFACE LOW DEVELOPS AND MOVES NORTHEASTWARD OUT OF THE LOWER  
MS VALLEY DURING THE DAY SATURDAY, MOVING TOWARDS THE MID-ATLANTIC  
BY SUNDAY MORNING. BEST CHANCE FOR RAINFALL ON SATURDAY SHOULD  
BE ACROSS THE WESTERN CWA AND THE UPSTATE. RAINFALL SHOULD  
OVERSPREAD THE ENTIRE CWA SATURDAY NIGHT INTO SUNDAY MORNING AS  
THE BEST MOISTURE TRANSPORT AND UPPER DYNAMICS MOVE INTO THE  
AREA. RAINFALL EXPECTED TO BE A LITTLE HEAVIER WITH THIS SYSTEM  
DUE TO IT TAPPING INTO DEEPER MOISTURE PROFILES. THE WINDOW FOR  
RAINFALL SHOULD BE ENDING BY LATE SUNDAY MORNING AS THE UPPER  
TROUGH MOVES IN AND THE SURFACE FRONT PUSHES THROUGH.  
BEHIND THE FRONT, WINDS WILL BE BREEZY ON SUNDAY AND MAY RESULT  
IN THE NEED FOR A LAKE WIND ADVISORY.  
 
COLD AND DRY ARCTIC HIGH PRESSURE SETTLES TOWARDS THE AREA  
SUNDAY NIGHT INTO THE EARLY PORTIONS OF NEXT WEEK. COLD AIR  
REMAINS INTO TUESDAY, WITH SOME MODERATION OF TEMPERATURES  
BEGINNING BY WEDNESDAY.  
 

 
   
AVIATION /00Z THURSDAY THROUGH MONDAY/
 
 
EXPECT MAINLY VFR CONDITIONS THROUGH THE 24-HOUR TAF PERIOD.  
 
DRY HIGH PRESSURE RIDGING INTO THE FORECAST AREA WILL DOMINATE  
TONIGHT. THE DRY AIR MASS SHOULD HELP PREVENT FOG EXCEPT  
POSSIBLY AT THE RIVER VALLEY TERMINALS OF AGS AND OGB. WE  
CONTINUED TO FORECAST A PERIOD OF IFR FOG AT THESE TERMINALS.  
THERE WILL BE INCREASED MOISTURE AHEAD OF A WEAK FRONT THURSDAY.  
THE GFS AND NAM MOS SUPPORTED A VFR CEILING DEVELOPING DURING  
THE AFTERNOON. THE MODELS DEPICT THE MORE SIGNIFICANT LIFT AND  
MOISTURE STAYING NORTH OF THE TERMINALS. THE SHOWER CHANCE  
TOWARD THE END OF THE PERIOD WAS TOO LOW TO INCLUDE IN THE  
TERMINAL FORECASTS AT THIS TIME. WIND WILL BE LIGHT AND VARIABLE  
ASSOCIATED WITH THE RIDGING THROUGH THE MORNING. THE NAM AND GFS  
MOS SUPPORT SOUTH TO SOUTHWEST WIND 5 TO 10 KNOTS DEVELOPING  
AHEAD OF THE FRONT DURING THE AFTERNOON.  
 
EXTENDED AVIATION OUTLOOK...A WEAK FRONT LINGERING IN THE AREA  
MAY BRING RESTRICTIONS DURING THE REST OF THURSDAY NIGHT AND  
FRIDAY. A MORE POTENT STORM SYSTEM WILL CROSS THE AREA SATURDAY  
AND SUNDAY WITH WIDESPREAD IFR ESPECIALLY SATURDAY NIGHT INTO  
SUNDAY MORNING. BREEZY CONDITIONS MAY OCCUR SATURDAY NIGHT  
THROUGH SUNDAY.  
 

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

 
 

 
SYNOPSIS...99  
NEAR TERM...99  
SHORT TERM...99  
LONG TERM...99  
AVIATION...99  
 
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