036  
FXUS62 KCAE 261453  
AFDCAE  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE COLUMBIA SC  
1053 AM EDT MON SEP 26 2016  
   
SYNOPSIS
 
 
AN UPPER-LEVEL RIDGE WILL MOVE OFF THE COAST TODAY. A STALLED  
WEAK COLD FRONT OVER THE NORTHERN MIDLANDS WILL PROVIDE A FOCUS  
FOR SCATTERED SHOWERS AND A FEW THUNDERSTORMS. ANOTHER COLD FRONT  
WILL CROSS THE AREA TUESDAY NIGHT INTO WEDNESDAY. THE AIR MASS  
BEHIND THIS SYSTEM WILL BRING DRY WEATHER AND MORE SEASONABLE  
TEMPERATURES FOR THE LATTER HALF OF THE WEEK INTO THE WEEKEND.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
WEAK BACKDOOR FRONT THAT WAS PUSHING THROUGH NC EARLIER SEEMS TO  
HAVE SLOWED OR EVEN STALLED NEAR THE NC/SC BORDER IN THE PEE DEE  
REGION. STRATUS CLOUDS WILL PERSIST FOR MUCH OF THE REST OF THE  
MORNING ASSISTED BY LOW-LEVEL MOISTURE FROM THE ATLANTIC.  
 
WEAK UPPER RIDGE CURRENTLY OVER THE AREA WILL FLATTEN AND SHIFT EAST  
TODAY AS A DIGGING UPPER TROUGH/CLOSED LOW MOVES INTO THE GREAT  
LAKES REGION THIS AFTERNOON AND TONIGHT, DRIVING A COLD FRONT INTO  
THE MOUNTAINS THIS AFTERNOON AND SLOWING ITS PUSH TOWARD THE  
FORECAST AREA OVERNIGHT. A BAND OF ENHANCED MOISTURE WITH  
PRECIPITABLE WATER VALUES AROUND 1.7-1.8 INCHES WILL PRECEDE THE  
APPROACHING FRONT. THE INCREASED MOISTURE COMBINED WITH SURFACE  
HEATING SHOULD SUPPORT WEAK TO MODERATE INSTABILITY THIS AFTERNOON  
WITH SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED ALONG AND SOUTH OF  
THE STALLED DIFFUSE FRONTAL BOUNDARY CURRENTLY OVER THE NORTHERN  
MIDLANDS. THIS BOUNDARY MAY SERVE AS A FOCUS FOR CONVECTION BUT  
THERE IS SOME UNCERTAINTY REGARDING THE STRENGTH OF CONVERGENCE  
GIVEN THE BROAD SOUTHEASTERLY FLOW. THE LATEST SPC HRRR INDICATING  
THE BEST CHANCE FOR PRECIPITATION THIS AFTERNOON PRIMARILY ALONG  
THE SOUTHERN MIDLANDS DUE TO A WEAK UPPER LOW OVER THE AREA.  
OVERALL, WILL CONTINUE MENTION OF CHANCE POPS OVER THE ENTIRE AREA  
THIS AFTERNOON.  
 
TEMPERATURES TODAY WILL AGAIN BE WELL ABOVE NORMAL IN THE MID TO  
UPPER 80S WITH OVERNIGHT LOWS TONIGHT IN THE UPPER 60S.  
 

 
   
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
 
 
TUESDAY LOOKS TO PROVIDE THE BEST CHANCE FOR PRECIPITATION ACROSS  
THE FORECAST AREA AS PRECIPITABLE WATER VALUES MAXIMIZE JUST AHEAD  
OF THE COLD FRONT WITH VALUES APPROACHING 1.8-1.9 INCHES WITH UPPER  
HEIGHT FALLS AND MODERATE INSTABILITY FORECAST. THE COLD FRONT IS  
SLOW TO PUSH THROUGH THE FORECAST AREA TUESDAY AFTERNOON AND TUESDAY  
NIGHT AS THE 500MB FLOW BACK MORE SOUTHERLY, NEARLY PARALLEL TO THE  
FRONT AS THE UPPER TROUGH AMPLIFIES. THE FRONT EVENTUALLY PUSHES  
THROUGH ON WEDNESDAY AS THE UPPER LEVEL CLOSED LOW DROPS SOUTHWARD  
INTO THE OHIO VALLEY AND MUCH DRIER AIR PUSHES INTO THE AREA FROM  
THE NORTHWEST WITH PRECIPITABLE WATER VALUES DROPPING BELOW AN INCH  
BY WEDNESDAY EVENING.  
 
WILL CARRY HIGH CHANCE POPS ACROSS THE FORECAST AREA ON TUESDAY INTO  
TUESDAY EVENING WITH DIMINISHING POPS LATE TUESDAY NIGHT AS THE  
ATMOSPHERE STABILIZES AND CONTINUE HIGHER POPS ON WEDNESDAY ACROSS  
THE EASTERN HALF OF THE FORECAST AREA WITH LOWERING POPS THROUGH THE  
AFTERNOON FROM WEST TO EAST AS DRIER AIR FILTERS INTO THE REGION.  
 
TEMPERATURES WILL REMAIN ABOVE NORMAL WITH HIGHS TUESDAY IN THE MID  
TO UPPER 80S AND SLIGHTLY COOLER ON WEDNESDAY IN THE LOWER TO MID  
80S. OVERNIGHT LOWS TUESDAY NIGHT WILL REMAIN MILD IN THE MID TO  
UPPER 60S WHILE TEMPERATURES WILL DROP A COUPLE OF CATEGORIES FOR  
WEDNESDAY NIGHT WITH MIN TEMPERATURES IN THE UPPER 50S TO LOWER 60S.  
 

 
   
LONG TERM /THURSDAY THROUGH SUNDAY/
 
 
MEDIUM RANGE MODELS ARE IN REASONABLE AGREEMENT IN THE OVERALL UPPER  
PATTERN SHOWING A CLOSED LOW SOMEWHERE IN THE VICINITY OF THE  
CENTRAL APPALACHIANS OR EASTERN TENNESSEE VALLEY THURSDAY WHICH THEN  
SLOWLY MIGRATES NORTHWARD INTO THE OHIO VALLEY OVER THE WEEKEND. AT  
THE SURFACE, COOLER AND DRIER CONTINENTAL HIGH PRESSURE WILL BUILD  
OVER THE FORECAST AREA WITH PRECIPITABLE WATER VALUES WELL BELOW AN  
INCH. DESPITE VERY COLD 500MB TEMPERATURES AROUND -12C TO -16C OVER  
THE AREA THU/FRI WITH STEEP MID LEVEL LAPSE RATES, THE LACK OF  
MOISTURE SHOULD LIMIT OR PRECLUDE PRECIPITATION ASSOCIATED WITH THE  
UPPER LOW, ALTHOUGH EXPECT SOME CLOUD COVER.  
 
TEMPERATURES DURING THIS PERIOD WILL FEEL MUCH MORE SEASONABLE WITH  
NEAR NORMAL TEMPERATURES. HIGHS WILL BE IN THE UPPER 70S TO LOWER  
80S AND OVERNIGHT LOWS WILL BE IN THE MID TO UPPER 50S.  
 

 
   
AVIATION /14Z MONDAY THROUGH FRIDAY/
 
 
BACK DOOR FRONT APPEARS TO HAVE PUSHED SOUTH INTO THE NE FA AND  
STALLED. EVEN SOUTH OF THE FRONT, MOIST LOW LEVELS AND AN E TO SE  
BOUNDARY LAYER FLOW PROMOTING DEVELOPMENT OF STRATUS AND SOME FOG,  
WITH MVFR TO IFR CONDITIONS PERSIST AT THE TERMINALS UNTIL AROUND  
16Z-17Z, THEN BECOMING VFR.  
 
BACK DOOR FRONT EXPECTED TO REMAIN NE OF OUR TERMINALS, AND  
EVENTUALLY BECOME DIFFUSE OR DRIFT NORTH AS A WARM FRONT AHEAD OF A  
COLD FRONT APPROACHING FROM THE NW. MEANWHILE, UPPER AND SURFACE LOW  
TO DRIFT NW TOWARDS THE LOWER SC COAST TODAY. DAYTIME HEATING AND AN  
ONSHORE FLOW TO PROVIDE POTENTIAL FOR SCATTERED SHOWERS/ISOLATED  
THUNDERSTORMS THIS AFTERNOON, MAINLY S FA. WILL MENTION VCSH AT  
DNL/AGS/OGB. OTHER CONVECTIVE ACTIVITY ALONG OR AHEAD OF THE  
APPROACHING FRONT LATE TODAY/THIS EVENING APPEARS WILL REMAIN NORTH  
OF THE TERMINALS. MOIST LOW LEVELS SUGGESTS DETERIORATING CONDITIONS  
ON TAP AGAIN LATE TONIGHT.  
 
EXTENDED AVIATION OUTLOOK...STRATUS/FOG POSSIBLE LATE MONDAY  
NIGHT/EARLY TUESDAY MORNING. CHANCE OF SHOWERS AND THUNDERSTORMS,  
AND ASSOCIATED RESTRICTIONS, TUESDAY/TUESDAY NIGHT. NO IMPACTS TO  
AVIATION EXPECTED WEDNESDAY AFTERNOON THROUGH FRIDAY.  
 

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

 
 

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab SC Page
The Nexlab GA Page Main Text Page