Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 221126 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 626 AM EST SUN DEC 22 2014 .SYNOPSIS... MOISTURE WILL OVERRUN A COOL SURFACE AIRMASS TODAY LEADING TO PERIODS OF LIGHT RAIN. THIS AIRMASS LIFTS OUT ON TUESDAY CLEARING THE PATH FOR WARMER TEMPERATURES AND EVEN MORE MOISTURE. A COLD FRONT MAY ADD SOME THUNDER WEDNESDAY AND WEDNEDAY NIGHT. DRY AND SEASONABLE WEATHER RETURNS FOR CHRISTMAS AND THE DAYS THAT FOLLOW. && .NEAR TERM /THROUGH TONIGHT/...
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AS OF 630 AM MONDAY...SURFACE LOW PRESSURE IS MOVING NE ALONG A FRONT STALLED ABOUT 40 MILES SOUTHEAST OF CAPE FEAR. 00Z MODELS SHOWED A SURPRISING DEGREE OF SPREAD IN HOW THEY HANDLE THE FRONT...BUT FORTUNATELY MY FORECAST DECISION LOOKS EASY: THE 00Z GFS WAS HORRIBLE EVEN IN ITS INITIALIZATION AND IS BEING AVOIDED. THIS FORECAST IS BASED ON THE 00Z NAM WHICH INITIALIZED WELL AND LOOKS REALISTIC IN ITS MAINTENANCE OF THE COOL WEDGE AIRMASS THROUGH THE DAY. UPDATE FOR 06Z MODELS: THE 06Z GFS WAS A LITTLE BETTER THAN THE 00Z VERSION BUT STILL TOO FAR WEST WITH THE COASTAL FRONT. THE NAM CONTINUES TO BE THE PREFERRED MODEL. WARM ADVECTION AND LIFT ON THE 295K-300K ISENTROPIC SURFACES BOTH TAPER OFF AROUND SUNRISE. PLENTY OF LOW-LEVEL MOISTURE SHOULD CONTINUE...BUT WITH LITTLE IF ANY SYNOPTIC LIFT IS EXPECTED DURING THE DAY. THIS SHOULD MAINTAIN DENSE LOW CLOUDS AND MAYBE SOME PATCHY DRIZZLE. INTERESTINGLY WITH MARGINALLY UNSTABLE CONDITIONS ALOFT ROOTED IN THE 875-850 MB LAYER THERE ARE SEVERAL CLUSTER OF SHOWERS AND EVEN ISOLATED THUNDERSTORMS FIRING ACROSS THE AREA. I HAVE ADDED HIGHER POPS THROUGH THE MORNING HOURS TO ACCOUNT FOR THIS CONVECTIVE ACTIVITY WHICH WAS NOT ANTICIPATED EARLIER ON THE MIDNIGHT SHIFT. WITH SUN ANGLES AS LOW AS THEY GET AND A CLASSIC WEDGE PATTERN... LOOK FOR TEMPERATURES TO HARDLY BUDGE TODAY: HIGHS SHOULD RANGE FROM 42-46 INLAND TO 47-50 AT THE BEACHES. LOW CLOUDS CONTINUE TONIGHT. ISENTROPIC LIFT MAY INCREASE AFTER MIDNIGHT...ESPECIALLY ACROSS INTERIOR AREAS WHERE COLD AIR DEPTH AND FRONTAL SLOPE WILL BE GREATEST. THEREFORE I HAVE POPS RAMPING BACK UP TOWARD 40 PERCENT LATE. THE COASTAL FRONT MAY ALSO BEGIN TO MOVE WESTWARD LATE AS HIGH PRESSURE RETREATS OUT OF NEW ENGLAND AND SURFACE PRESSURES FALL ACROSS THE CAROLINA AND MID-ATLANTIC PIEDMONT REGION. THE COASTAL FRONT MAY ACTUALLY APPROACH GEORGETOWN BY DAYBREAK TUESDAY. THIS COULD CREATE AN INTERESTING HOURLY TEMPERATURE PROFILE WITH LOWS OCCURRING IN THE EVENING AND TEMPERATURES RISING LATE.
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&& .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 AM MONDAY...VERY ACTIVE WEATHER EXPECTED FOR THE DURATION OF THE PERIOD. WEDGE WILL FINALLY BE BREAKING DOWN ON TUESDAY. THE SPEED AT WHICH THIS OCCURS, WHICH IS NOTORIOUSLY DIFFICULT TO MODEL, WILL MODULATE HIGH TEMPS. CURRENT FCST LEANS MORE ON THE SLOWER WRF KEEPING MID 50S INLAND WHILE COASTAL LOCALES GET INTO MID/UPPER 60S. DEEP SWRLY FLOW OF MOISTURE TO BRING PLENTY OF CLOUDS AND OCCASIONAL RAIN FROM TIME TO TIME. PINNING DOWN WHERE RAIN WILL BE HEAVIEST IS DIFFICULT AT THIS TIME. RAINFALL RATES TO INCREASE TUESDAY NIGHT INTO WEDNESDAY AS STRONGER FLOW AND DYNAMICS SPREAD ACROSS THE REGION WHILE COLD FRONT APPROACHES FROM THE NORTH AND WEST. THE STRONGER RESULTING FLOW WILL BRING EVEN MILDER AIR INTO THE COASTAL PLAIN AND HIGHS IN THE 70S APPEAR LIKELY DESPITE THE CLOUDS AND RAIN. DESPITE THE WARMTH FORECAST SOUNDINGS SHOW SUCH POOR LAPSE RATES THAT INSTABILITY IS REALLY GOING TO BE TOUGH TO COME BY, MAYBE ENOUGH ENOUGH TO WORRY ABOUT HSLC SETUP. HAVE LEFT ISO THUNDER AS SOME FAIRLY STRONG VERTICAL MOTION MAY IMPACT THE REGION LATE IN THE PERIOD. WEDNESDAY NIGHT`S LOWS MAY BE VERY MILD LIKE TUESDAY NIGHT SAVE FOR SOME COLD ADVECTION RELATED TO FROPA TOWARDS DAYBREAK THURSDAY. SIMILARLY RAIN WILL BE RAPIDLY SHUTTING OFF FROM WEST TO EAST LATE WEDNEDAY NIGHT...THE EXACT TIMING LIKELY NEEDING OF SOME REFINEMENT IN FUTURE FORECASTS. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 3 AM MONDAY...CHRISTMAS AND THE FEW DAYS THAT FOLLOW WILL FEATURE A RETURN OF SUNSHINE...NOT SEEN IN QUITE A WHILE. ALSO SINCE THE UPPER WAVE DRIVING THE FRONT THROUGH NOW RETAINS A DEFINED POSITIVE TILT THE COLD ADVECTION APPEARS QUITE TEMPERED AND THE HOLIDAY WEEKEND NO LONGER SEEMS TO OFFER UP UNSEASONABLY COOL TEMPERATURES IN FAVOR OF SEASONABLE WEATHER IF NOT A FEW DEGREES ABOVE. MOISTURE MAY BE ON THE RISE BY SUNDAY AS A WEAK COLD FRONT APPROACHES IN A STILL RATHER LOW AMPLITUDE PATTERN ALOFT. && .AVIATION /12Z MONDAY THROUGH FRIDAY/...
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AS OF 12Z...LIFR CIGS/MVFR VSBYS AT THE COASTAL TERMINALS THIS MORNING WHILE INLAND TERMINALS HAVE IFR CIGS/VFR VSBYS. OCCASIONALLY VSBYS DROP A CATEGORY OR TWO LOWER AS LIGHT RAIN...WITH ISOLATED EMBEDDED CONVECTIVE SHOWERS/THUNDERSTORMS MOVE NE ACROSS THE AREA. CIGS LESS THAN 600-700 FEET AND VSBYS 3-5SM WILL BE LIKELY THIS MORNING. THE BULK OF THE SHOWERS/ISOLATED THUNDERSTORMS PER RADAR LOOPS WILL MOVE BETWEEN THE INLAND AND COASTAL TERMINALS THIS MORNING SO WILL NOT INDICATE VCTS IN TAFS. VSBYS COULD DROP TO 1-3SM IN LIGHT SHOWERS/BR ESPECIALLY AT THE COASTAL TERMINALS. CIGS SHOULD LIFT ABOVE 600-700 FEET WITH VSBYS 6SM+ BY LATE MORNING/EARLY AFTERNOON. CIGS FLIRT AROUND 1K LATER THIS AFTERNOON BUT CONFIDENCE IS NOT HIGH. EVEN IF CIGS RISE CIGS WILL DROP AGAIN AOB 600-700 FEET BY MIDNIGHT Z. EXTENDED OUTLOOK...LIFR/IFR CIGS TUE WITH INCREASING CHANCES OF SHOWERS. MVFR COASTAL TERMINALS LATER IN THE DAY. WED EXPECT SHOWERS/MVFR AND GUSTY WINDS AHEAD OF A COLD FRONT. GUSTY WEST WINDS AND VFR THU BEHIND THE FRONT. VFR ON FRI.
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&& .MARINE...
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NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM MONDAY...A COASTAL FRONT IS STALLED ABOUT 40 MILES SOUTHEAST OF CAPE FEAR. LOW PRESSURE IS MOVING NE ALONG THE FRONT AND SHOULD BE NORTH OF CAPE FEAR BY MID-MORNING. THIS WILL TAKE THE PERIOD OF STRONGEST OF NE WINDS NORTH OF THE AREA...REPLACED WITH A LIGHTER NORTHERLY WIND THAT SHOULD LAST INTO TONIGHT. THE SMALL CRAFT ADVISORY HAS EXPIRED FOR THE SC WATERS...HOWEVER IT WILL REMAIN IN EFFECT THROUGH 9 AM FOR THE NC WATERS...MAINLY TO ALLOW SEAS TIME TO SUBSIDE BELOW 6 FEET. THE FRYING PAN SHOALS BUOY IS STILL REPORTING 6.6 FOOT SEAS AT LAST REPORT. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 AM MONDAY...TUESDAY CHARACTERIZED BY WEAKENING WEDGE OF HIGH PRESSURE OVER LAND. THE SPEED AT WHICH THIS OCCURS IS ALWAYS A BIT UNCERTAIN AND THIS WILL AFFECT HOW QUICKLY LOCAL WINDS VEER AND INCREASE IN SPEED. HAVE OPTED FOR THE SLOWER MODEL SOLUTION WHICH WILL KEEP THE MAIN DETERIORATION OF CONDITIONS OFF UNTIL TUESDAY NIGHT. AT THIS TIME THE SSWRLY FLOW REALLY BECOMES ESTABLISHED IN A STRENGTHENING STATE AS LOW LEVEL WIND FIELDS CRANK UP AND A COLD FRONT AND STRONG UPPER TROUGH APPROACH. SMALL CRAFT ADVISORY EXPECTED BY TUES NIGHT. WIND AND SEAS ONLY INCREASE FROM THERE AS THE APPROACHING BOUNDARY TIGHTENS THE GRADIENT AND THE APPROACH OF THE UPPER WAVE STRENGTHENS LOW LEVEL WIND FIELDS. FROPA EXPECTED TOWARDS THE END OF THE PERIOD WITH AN ABRUPT WIND VEER. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 3 AM MONDAY...THE LONG TERM STARTS OFF WITH SMALL CRAFT ADVISORY FLAGS FLYING JUST FOLLOWING VIGOROUSLY DRIVEN COLD FRONT. HOWEVER THE COLD SURGE ITSELF IS RATHER UNIMPRESSIVE AND WINDS AND SEAS SHOULD BOTH DROP OFF RATHER NICELY AS THE DAY WEARS ON. TOUGH TO RULE OUT A PERIOD OF SCEC THOUGH AS THE SHARP WIND SHIFT COULD LEAD TO RATHER STEEP WAVE FACES EVEN AS THEIR OVERALL HEIGHT DECREASES. FRIDAY BRINGS A LIGHT OFFSHORE FLOW AS HIGH PRESSURE SLOWLY BUILDS IN FROM THE WEST.
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&& .TIDES/COASTAL FLOODING... AS OF 3 AM MONDAY...TIDAL ANOMALIES ARE RUNNING ABOUT +1.0 FOOT AT WRIGHTSVILLE BEACH AND MYRTLE BEACH THIS MORNING. NE WINDS ALONG THE COAST ARE LARGELY RESPONSIBLE FOR THIS SURGE. ASTRONOMICAL TIDAL RANGES ARE LARGER THAN NORMAL DUE TO THE NEW MOON WHICH IS TODAY. THIS MORNING`S HIGH TIDE WILL OCCUR AROUND 7:15 AM...AND WITH THE ADDITION OF THE SURGE MAY APPROACH MINOR FLOOD THRESHOLDS NORTH OF CAPE FEAR. THE COASTAL FLOOD ADVISORY WILL REMAIN IN EFFECT HERE FOR POSSIBLE MINOR FLOODING. SOUTH OF CAPE FEAR WINDS SHOULD BE BACKING MORE NORTHERLY OVER THE NEXT FEW HOURS WHICH WILL REDUCE THE AMOUNT OF SURGE...AND NO ADVISORIES ARE PLANNED HERE. && .ILM WATCHES/WARNINGS/ADVISORIES...
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SC...NONE. NC...COASTAL FLOOD ADVISORY FROM 6 AM TO 9 AM EST MONDAY FOR NCZ106- 108. MARINE...SMALL CRAFT ADVISORY UNTIL 9 AM EST MONDAY FOR AMZ250-252.
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&& $$ SYNOPSIS...MBB NEAR TERM...TRA SHORT TERM...MBB LONG TERM...MBB AVIATION...MRR TIDES/COASTAL FLOODING...TRA

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