696  
FXUS62 KILM 240049  
AFDILM  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE WILMINGTON NC  
849 PM EDT MON OCT 23 2017  
   
SYNOPSIS
 
 
A STRONG COLD FRONT WILL APPROACH FROM THE WEST TODAY AND SLOW,  
FINALLY MOVING COMPLETELY OFFSHORE TUESDAY AFTERNOON. SHOWERS  
AND THUNDERSTORMS ARE EXPECTED ALONG AND AHEAD OF THE FRONT WITH  
THE POSSIBILITY FOR A LINE OF STRONG TO SEVERE THUNDERSTORMS  
THIS EVENING AND TONIGHT. IN THE WAKE OF THE FRONT, DRY AND  
COOL AIR IS EXPECTED THROUGH THURSDAY AS CANADIAN HIGH PRESSURE  
TAKES HOLD. A WARMING TREND BEGINS FRIDAY. SHOWER CHANCES  
INCREASE SATURDAY AS A WEAK AREA OF LOW PRESSURE DEVELOPS AHEAD  
OF A SECOND COLD FRONT.  
 

 
   
NEAR TERM /THROUGH TUESDAY/
 
 
AS OF 830 PM MONDAY...AXIS OF SURFACE-BASED INSTABILITY WAS  
MOVING EASTWARD ACROSS THE PEE DEE REGION AS OF 00Z, WITH LI'S  
OF -2C TO -3C EXTENDING FROM NEAR LBT SOUTHWARD THROUGH  
KINGSTREE. MODEST SURFACE PRESSURE FALLS WERE OCCURRING JUST  
EAST OF THIS AXIS OF INSTABILITY, AND WILL TRANSITION EASTWARD  
AND OFF THE COAST OVER THE NEXT FEW HOURS. ALTHOUGH BACKING OF  
THE SURFACE WINDS IN RESPONSE TO THESE PRESSURE FALLS HAS BEEN  
MODEST ACROSS THE CWA, THE SHEAR PROFILES AS EVIDENCED BY KLTX  
VWP WILL REMAIN CONDUCIVE FOR STORM ROTATION THROUGH THE REMAINDER  
OF THE EVENING. LATEST HRRR INDICATES THE THUNDERSTORM ACTIVITY  
WILL MOVE OFF THE COAST AROUND 06-07Z.  
 
COOL ADVECTION LAGS CONSIDERABLY BEHIND THE WIND-SHIFT THOUGH  
DEWPOINTS MAY START DROPPING TUESDAY AFTERNOON TEMPERATURES WILL  
STILL WARM UP INTO THE UPPER 70S, A SOLID CATEGORY ABOVE  
CLIMATOLOGY.  
 

 
   
SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/
 
 
AS OF 300 PM MONDAY...VERY QUIET CONDITIONS WILL SETTLE INTO  
THE AREA AS A DEEP FULL LATITUDE MID LEVEL TROUGH MOVES FROM THE  
TENNESSEE VALLEY TO JUST OFFSHORE THROUGH THE PERIOD.  
PRECIPITABLE WATERS DIP TO NEAR ONE QUARTER OF AN INCH BY LATE  
IN THE PERIOD. AT THE SURFACE A SOMEWHAT BLUSTERY PRESSURE  
GRADIENT WILL RESIDE ACROSS THE AREA AND THIS IS REFLECTED N THE  
GUIDANCE. THERE MAY BE SOME DECOUPLING EARLY THURSDAY MORNING  
ALLOWING TEMPERATURES TO POSSIBLY DROP TO THE COOLEST READINGS  
OF THE SEASON IN SOME AREAS WITH LOWER TO MID 40S AREA WIDE.  
 

 
   
LONG TERM /THURSDAY THROUGH MONDAY/
 
 
AS OF 300 PM MONDAY...VERY COOL TEMPERATURES START THE EXTENDED AS  
CANADIAN HIGH PRESSURE SETTLES ACROSS THE AREA BEFORE PUSHING  
OFFSHORE FRIDAY. TEMPS THURSDAY WILL LIKELY BE ABOUT 5 DEGREES BELOW  
CLIMO BEFORE RECOVERING TO MORE SEASONABLE TEMPS FRIDAY AS THE  
SURFACE HIGH SHIFTS OFFSHORE. MOISTURE WILL BEGIN TO INCREASE  
SATURDAY ON INCREASING SOUTHERLY WINDS AS A PRE-FRONTAL AIRMASS  
RETURNS AHEAD OF A DEEP MID-LEVEL TROUGH PUSHING THROUGH THE MS VLY.  
THIS WILL DRIVE A COLD FRONT ACROSS THE AREA SATURDAY NIGHT INTO  
SUNDAY. AHEAD OF THIS FEATURE, A WEAK AREA OF LOW PRESSURE MAY  
DEVELOP AND MOVE JUST OFF THE COAST, AND WHILE TOTAL COLUMN  
MOISTURE REMAINS CONFINED BELOW 700MB, SHOWERS ARE POSSIBLE LATE  
SATURDAY THROUGH SUNDAY MORNING ASSOCIATED WITH THIS FEATURE.  
THIS FRONT WILL BRING THE POTENTIAL FOR THE COLDEST AIR OF THE  
SEASON BEHIND IT, AS 850MB PROGS DROP BELOW 0C AND EXTENDED MOS  
NUMBERS FEATURE VALUES AS MUCH AS 10 DEGREES BELOW CLIMO EARLY  
NEXT WEEK.  
 

 
   
AVIATION /00Z TUESDAY THROUGH SATURDAY/
 
 
AS OF 23Z...LATEST RADAR SHOWING PRECIPITATION MOVING UP THE SC  
COAST SOON TO IMPACT KMYR AND KCRE. LIGHT RAIN ALREADY AT KFLO  
AND KLBT WITH NOTHING YET AT KILM. FORECAST FOR THE OVERNIGHT  
PERIOD STILL A BIT TRICKY WITH VAD WIND PROFILE SHOWING SOME  
VEERING BETWEEN 8K AND 17K WITH 35 TO 45 KT WINDS. AS FRONT  
PUSHES TO THE EAST STORM MOTION IS MOVING ALL CELLS TO THE NE AT  
GREATER THAN 30 MPH. IMPACTS WILL AFFECT ALL TERMINALS THROUGH  
THE EVENING/OVERNIGHT PERIOD WITH HIGH CONFIDENCE IN MVFR AND  
POSSIBLE IFR CONDITIONS IN VSBY AND CEILING. HAVE MENTIONED TSTM  
ACROSS THE INLAND TERMINALS BUT NOT TO CONFIDENT AT THE COASTAL  
TERMINALS ALTHOUGH CANNOT TOTALLY RULED OUT BUT WILL NOT  
MENTION AT TERMINALS.  
 
GUSTY SSE TO S WINDS WILL PREVAIL OVERNIGHT UNTIL FROPA AND  
WILL MENTION LOW CEILINGS AND VSBY ACROSS KLBT AND KFLO WITH  
FOG AS WINDS ABATE BEHIND THE FRONT. WEATHER WILL IMPROVE FROM  
WEST TO EAST ACROSS THE TERMINALS. CONCERN MIGHT BE FOR SOME  
WIND SHEAR AROUND 03Z NEAR THE COAST BUT WILL KEEP AN EYE ON  
THIS AS VAD WINDS ARE PRETTY UNIFORM WITH THE WIND SPEEDS FROM  
THE SFC UP TO ABOUT 4-5K. MAIN CONCERN FOR ALL TERMINALS WILL BE  
BETWEEN 00Z AND 06Z BEFORE CONDITION SLOWLY IMPROVE. AFTER  
25/15Z VFR CONDITIONS ACROSS THE REGION.  
 
EXTENDED OUTLOOK... VFR WEDNESDAY THROUGH FRIDAY. SLIGHT CHANCE FOR  
SHOWERS SATURDAY.  
 

 
   
MARINE
 
 
NEAR TERM /THROUGH TUESDAY/...  
AS OF 830 PM MONDAY...LATEST BUOY OBS ARE INDICATING STRONG  
SOUTHERLY WINDS ACROSS THE WATERS, WITH GUSTS OF 25-30 KNOTS.  
SEAS AT BUOY 41013 WERE RUNNING NEAR 8 FEET. LATEST GUIDANCE  
SUGGESTS WINDS WILL DIMINISH LATE TONIGHT ACROSS THE SC WATERS,  
AND EARLY TUESDAY MORNING NORTH OF CAPE FEAR. SEAS WILL SUBSIDE  
BELOW SCA THRESHOLDS BEGINNING EARLY TUESDAY SOUTH OF LITTLE  
RIVER INLET, AND BY EARLY AFTERNOON ACROSS THE WATERS NORTH OF  
LITTLE RIVER INLET IN THE WAKE OF THE WIND SHIFT. WON'T MAKE  
CHANGES TO THE SCA AT THIS TIME, BUT IF THIS TIMING EXPECTATION  
HOLDS, WE MAY BE ABLE TO REMOVE THE SOUTHERN WATERS FROM THE  
SCA A LITTLE EARLIER ON TUESDAY THAN 18Z.  
 
SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...  
AS OF 300 PM MONDAY...NORTHWEST WINDS OF 10-15 KNOTS AND ON  
OCCASION 15-20 KNOTS WILL PREVAIL ACROSS THE AREA THROUGH THE  
PERIOD. THE PERSISTENCE WILL BE PROVIDED BY A VERY DEEP AND SLOW  
MID LEVEL TROUGH AT 500MB THAT TRUDGES ACROSS THE CONUS FROM  
THE MISSISSIPPI VALLEY. SIGNIFICANT SEAS WILL BE MOSTLY 2-4 FEET  
WITH THE HIGHER VALUES ACROSS THE OUTER WATERS WITH THE  
OFFSHORE FLOW.  
 
LONG TERM /THURSDAY THROUGH SATURDAY/...  
AS OF 300 PM MONDAY...HIGH PRESSURE MOVING OVERHEAD THE WATERS  
THURSDAY INTO FRIDAY WILL CREATE GUSTY NORTH WINDS EARLY  
THURSDAY BEFORE WEAKENING TO LESS THAN 10 KTS AND SHIFTING  
SLOWLY TO NE FRIDAY, AND THEN E ON SATURDAY. A SECONDARY FRONT  
APPROACHING VERY LATE SATURDAY MAY CAUSE WINDS TO UPTICK AGAIN  
AT THE END OF THE PERIOD. THE GUSTY NORTH WINDS EARLY WILL KEEP  
SEAS ELEVATED AT 3-4 FT THE FIRST HALF OF THURSDAY, BEFORE  
FALLING BACK TO 1-3 FT FRI AND SAT. THE INCREASED WINDS LATE  
SATURDAY MAY CAUSE SEAS TO BEGIN TO RISE AGAIN AT THAT TIME.  
 

 
   
ILM WATCHES/WARNINGS/ADVISORIES
 
 
SC...NONE.  
NC...NONE.  
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT TUESDAY FOR AMZ250-252-254-  
256.  
 

 
 

 
SYNOPSIS...JDW  
NEAR TERM...CRM  
SHORT TERM...SHK  
LONG TERM...JDW  
AVIATION...MAC  
 
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