Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 131058 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 657 AM EDT SAT SEP 13 2014 .SYNOPSIS... A FLOOD WATCH HAS BEEN ISSUED FOR SATURDAY AS A STALLED COLD FRONT CONTINUES UNSETTLED WEATHER ACROSS THE AREA. THIS FRONT WILL REMAIN IN THE VICINITY ON SUNDAY...BEFORE LIFTING BACK NORTH ON MONDAY...BUT UNSETTLED WEATHER WILL PERSIST. A STRONGER COLD FRONT WILL CROSS THE AREA ON TUESDAY...BRINGING COOLER AND DRIER WEATHER FOR THE LATTER HALF OF NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 600 AM SATURDAY...A FLOOD WATCH HAS BEEN POSTED FOR THE ENTIRE ILM CWA...AND IS IN EFFECT FROM 6 AM THIS MORNING THROUGH 6 AM SUNDAY MORNING. A STALLED FRONTAL BOUNDARY LYING EAST-WEST NEARLY ALONG THE NC-SC BORDER WILL LIKELY MEANDER BOTH NORTH AND SOUTH THROUGHOUT THE NEAR TERM PERIOD. INITIALLY...IT MAY TEMPORARILY PUSH NORTHWARD DUE TO A VIGOROUS UPPER S/W TROF PUSHING FROM THE GREAT LAKES TO THE NE STATES TODAY. THEN SETTLING BACK TO THE SOUTH TONIGHT...WITH MODELS HINTING THAT IT MAY DROP SOUTH OF THE ILM CWA DURING SUNDAY. PLENTY OF MOISTURE ON EITHER SIDE OF THE FRONTAL BOUNDARY WITH PWS 2+ INCHES. TO AID PCPN DEVELOPMENT... FORCING IE. UVVS...WILL BE PROVIDED BY THE SFC FRONT ITSELF...AND UPPER DYNAMICS IN THE FORM OF A S/W TROF OR VORT...WHICH WILL FURTHER PROVIDE ADDITIONAL LIFT. NORTH OF THE FRONT WILL OBSERVE OVERRUNNING TYPE PCPN...IE. STRATIFORM RAINS. HOWEVER...ELEVATED CONVECTION REMAINS A GOOD POSSIBILITY DUE TO ELEVATED INSTABILITY...IE. ELEVATED CAPE. SOUTH OF THE FRONT...THE CHARACTER OF THE PCPN WILL BE MORE CONVECTIVE. WITH THE FA LOCATED DIRECTLY ON EITHER SIDE OF THIS FRONT...THE CWA WILL THEN BE SUBJECTED TO PCPN THAT WILL MOVE ACROSS ALREADY SATURATED GROUNDS...OVER AND OVER AGAIN IE. TRAINING...WITH THE END RESULT LIKELY FLOODING. THUS...A 24 HR FLOOD WATCH HAS BEEN ISSUED FOR THE ENTIRE ILM CWA...IN EFFECT FROM 6AM SAT THRU 6AM SUN. VARIOUS MODEL MOS GUIDANCE INDICATE WIDESPREAD 80S FOR MAX TEMPS TODAY. DEPENDING ON WHICH SIDE OF THE FRONT ONE IS...THE RANGE WILL RUN FROM THE LOW 80S NORTHERN PORTIONS OF THE ILM CWA TO MID- UPPER 80S SOUTHERN PORTIONS OR SOUTH OF THE FRONT. THE WIDESPREAD CLOUDS AND PCPN MAY FURTHER PREVENT TEMPS FROM CLIMBING...ESPECIALLY NORTH OF THE FRONT WHERE UPPER 70S IS NOT OUT OF THE QUESTION. THE COOLER AND DRIER AIR BEHIND THE FRONT REMAINS WELL UPSTREAM...FROM VIRGINIA AND NORTHWARD. THUS...EVEN IF TEMPORARY FROPA DOES OCCUR...THE COOLER AND DRIER AIRMASS WILL REMAIN WELL UPSTREAM AND UNABLE TO INFILTRATE THE REGION DURING THIS PERIOD. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 300 AM SATURDAY...AN EXPANDING TROUGH AND A PERSISTENT RIDGE WILL ENGAGE IN BATTLE OVERHEAD THROUGH EARLY NEXT WEEK FOR POSITION OVER THE CAROLINAS. ALMOST LIKE THE OLD CHILDHOOD GAME OF "RED ROVER"...EACH FEATURE WILL TRY TO BREAK THROUGH THE OTHER...BUT THE RIDGE WILL CALL THE TROUGH OVER ONE TOO MANY TIMES...EARNING THE TROUGH A VICTORY...DISPLACING THE RIDGE BY MONDAY NIGHT. THIS FORCES THE COLD FRONT BELOW TO BECOME NEARLY STATIONARY SUNDAY AND MONDAY...WAVERING BACK AND FORTH ACROSS THE AREA...CONTINUING THE UNSETTLED WEATHER PATTERN. SURFACE FRONT WILL BE ALONG THE SOUTHERN TIER...OR JUST SOUTH...OF THE CWA DURING SUNDAY BEFORE SLOWLY LIFTING NORTH AGAIN ON MONDAY. WHILE INSTABILITY WILL BE LIMITED DUE TO WIDESPREAD CLOUD COVER...AND UPPER SUPPORT WILL REMAIN MINIMAL...PERSISTENT MOIST FLOW ATOP THE FRONT COMBINED WITH SURFACE CONVERGENCE ALONG IT (AND RESIDUAL BOUNDARIES) IN A VERY MOIST COLUMN WILL PRODUCE PERIODS OF RAIN/TSTMS SUNDAY AND MONDAY. BEST PRECIP CHANCES MAY BE IN THE SOUTHERN AND WESTERN ZONES SUNDAY AND THIS IS WHERE THE HIGHEST QPF IS EXPECTED...BUT ALL AREAS WILL LIKELY SEE SHOWERS AND STORMS. A BRIEF RESPITE IN CONVECTIVE COVERAGE WILL OCCUR WITH LOSS OF HEATING SUNDAY NIGHT...BEFORE MORE SCATTERED CONVECTION DEVELOPS MONDAY AS THE FRONT LIFTS TO THE NORTH PRODUCING A BRIEF PERIOD OF WAA AND SUMMER-LIKE CONVECTION. THIS WILL BE SHORT LIVED HOWEVER...AS THIS FRONT WILL RETURN BACK TO THE SOUTHEAST AS A COLD FRONT BENEATH A STRONG VORTICITY IMPULSE MOVING TO THE NORTH EITHER VERY LATE MONDAY NIGHT...OR JUST BEYOND THIS PERIOD. ANOTHER ROUND OF HEAVIER PRECIP MAY ACCOMPANY THIS FRONT LATE MONDAY HOWEVER...AND CANNOT AT ANY TIME FORECAST POP BELOW CHC THROUGH THE PERIOD...WITH HIGHEST OCCURRING SUNDAY AND THEN AGAIN LATE MONDAY. HIGHS SUNDAY WILL BE SEVERAL DEGREES BELOW NORMAL THANKS TO CLOUDS...RAIN...AND COOL NORTHERLY SURFACE FLOW...WITH MAX TEMPS EXPECTED TO REACH ONLY THE MID 70S FAR NW...TO MID 80S NEAR THE SOUTH SANTEE RIVER. THE AFOREMENTIONED WAA WILL DRIVE HIGHS INTO THE LOW/MID 80S CWA-WIDE ON MONDAY. LOWS SUNDAY NIGHT WILL DROP TO NEAR-NORMAL LEVELS OF THE MID 60S...BUT WILL BE SEVERAL DEGREES WARMER MONDAY NIGHT AHEAD OF THE NEXT COLD FRONT. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 300 SATURDAY...STRONG COLD FRONT WILL PUSH ACROSS THE AREA ON TUESDAY...USHERING IN COOL CANADIAN AIR FOR MOST OF THE UPCOMING WEEK. STRONG VORTICITY IMPULSE SPAWNING A SURFACE LOW PRESSURE WILL BE RACING EAST WELL NORTH OF THE AREA...BUT A STRONG COLD FRONT BEHIND THIS WILL DRAG ACROSS THE CWA DURING TUESDAY. A PERIOD OF UNSETTLED WEATHER IS EXPECTED TUESDAY WITH SHOWERS AND THUNDERSTORMS...BUT THIS FRONT SHOULD PUSH OFFSHORE BY WEDNESDAY AS A DEEP UPPER TROUGH DIVES INTO THE EAST. THEREAFTER...GUIDANCE CONTINUES TO DIFFER ON HOW FAR OFFSHORE THIS FRONT WILL STALL...WITH THE GFS CONTINUING TO INDICATE THAT IT WILL BE JUST OFFSHORE AND CONTINUE UNSETTLED CONDITIONS LOCALLY. THE ECMWF...WHICH IS PREFERRED...PUSHES THIS FRONT WELL OFF THE COAST...WHICH SEEMS ACCURATE BASED OFF THE STRENGTH OF THE UPPER TROUGH AND SINCE WE HAVE HAD SEVERAL FROPAS ALREADY THIS YEAR. USING THE ECMWF AS A GUIDE...WED-FRI WILL FEATURE DRYING CONDITIONS AND TEMPS AROUND 5 DEGREES BELOW CLIMO THANKS TO THE CANADIAN ORIGIN OF THE SURFACE HIGH RIDGING DOWN THE COAST. IN ADDITION...IT APPEARS THE AREA WILL SEE SUNSHINE FOR THE FIRST TIME IN SEVERAL DAYS BY WEDNESDAY. HOWEVER...MUST NOTE THE PERSISTENCE OF THE GFS WHICH KEEPS THE FRONT JUST OFF THE COAST AND DEVELOPS A LOW PRESSURE SYSTEM ALONG THE TAIL END OF THE BOUNDARY. THIS WOULD KEEP UNSETTLED CONDITIONS ACROSS THE AREA...ESPECIALLY NEAR THE COAST...WITH MORE WET WEATHER POSSIBLE LATE IN THE WEEK. WILL KEEP INHERITED LOW-CHC/SCHC POP FOR POTENTIAL...BUT WITH A SLIGHT DECREASE IN SPECIFIC VALUES TO ACCOUNT FOR THE MUCH DRIER ECMWF. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... AS OF 12Z...A NEARLY STATIONARY FRONT IS MEANDERING THROUGH THE REGION. ILM APPEARS TO BE NORTH OF THE FRONT...WITH HEAVY FOG AND A NORTHEAST WIND. LOOK FOR THE CONVECTION TO BREAK OUT VERY SIMILAR TO YESTERDAY...FIRST BEGINNING ALONG THE RESULTANT AND SPREADING INLAND AS THE AFTERNOON PROGRESSES. SHOULD BE SOME OCCASIONAL HEAVY RAIN WITH NICE CLOUD TO GROUND LIGHTNING STRIKES. THE FRONT MAY BRIEFLY WAVE NORTH OF ILM...WITH WINDS SHIFTING TO THE SOUTHEAST. TONIGHT...SOME FOG/STRATUS RETURNING...ESPECIALLY THE NORTHERN TERMINALS AS THE FRONT TRIES TO DRIFT SOUTH AGAIN. EXTENDED OUTLOOK...A CHANCE OF SHOWERS WITH MAINLY AFTERNOON THUNDERSTORMS/TEMPO MVFR THROUGH TUESDAY. && .MARINE... NEAR TERM/THROUGH TONIGHT/... AS OF 600 AM SATURDAY...WINDS AND TO A LESSER DEGREE SIGNIFICANT SEAS...WILL BE GOVERNED BY THE MEANDERING FRONTAL BOUNDARY DURING THIS PERIOD. THIS MEANS...WATERS NORTH OF THE FRONT WILL OBSERVE NE-E WINDS...AND SOUTH OF THE FRONT WILL SEE SE-SSW WINDS. THE SFC PG REMAINS LOOSE FOR THE MOST PART RESULTING WITH WIND SPEEDS AROUND 10 KT. HOWEVER...DEPENDING ON YOUR LOCATION BEHIND THE FRONT...THE NE-E WINDS THAT OCCUR COULD PRODUCE SPEEDS UP TO 15 KT IF THE SFC PG TIGHTENS ENOUGH. SIGNIFICANT SEAS WILL REMAIN DOCILE...AROUND 2 FT. THE MINI NE-E INCREASED WINDS BEHIND THE FRONT COULD PRODUCE SIG. SEAS UP TO 3 FT. AVERAGE PERIODS WILL RUN 4 TO 5 SECONDS. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 300 AM SATURDAY...COLD FRONT SOUTH OF THE WATERS TO START THE PERIOD WILL REMAIN NEARLY STATIONARY SUNDAY...BEFORE LIFTING BACK TO THE NORTH AS A WARM FRONT MONDAY. THIS DRIVES NE WINDS ALL SUNDAY AND INTO MONDAY...BEFORE VEERING TO BECOME S/SE LATE ON MONDAY. SPEEDS WILL BE 5-10 KTS REGARDLESS OF DIRECTION. A COLD FRONT WILL APPROACH AT THE VERY END OF THE SHORT TERM WITH WINDS BEGINNING TO VEER TO THE WEST LATE MONDAY NIGHT. SEAS WILL BE 1-3 FT THROUGH THE PERIOD...WITH A NE WIND WAVE PREDOMINANT ON SUNDAY...BECOMING SOUTHERLY DURING MONDAY. LONG TERM /TUESDAY THROUGH WEDNESDAY/... AS OF 300 AM SATURDAY...THE BEGINNING OF AN EXTENDED PERIOD OF POOR MARINE CONDITIONS EXPECTED TUESDAY AS A COLD FRONT CROSSES THE WATERS. ALTHOUGH WINDS TUESDAY WILL BE PRETTY LIGHT...5-10 KTS WITH SEVERAL VEERING WIND DIRECTIONS...THE CONFUSED SPECTRUM WILL COMBINE WITH THE SLOWLY AMPLIFYING LONG PERIOD 13-14 SEC SE SWELL ASSOCIATED WITH TROPICAL STORM EDOUARD MOVING THROUGH THE CENTRAL ATLANTIC...TO DRIVE INCREASING WAVE HEIGHTS. ADDITIONALLY...A NE SURGE WILL BEGIN TUESDAY NIGHT BEHIND THIS BOUNDARY...WITH NE WINDS RISING TO AROUND 15 KTS ON WEDNESDAY. THE COMBINATION OF THE LONG-PERIOD SWELL AND INCREASING WINDS WILL DRIVE WAVE HEIGHTS FROM 2-4 FT TUESDAY TO 4-6 FT WEDNESDAY...AND A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED BEGINNING WEDNESDAY. ALTHOUGH IT IS BEYOND THIS PERIOD...IT APPEARS WEDNESDAY COULD BE THE FIRST OF SEVERAL CONSECUTIVE DAYS WITH HEADLINES NEEDED ACROSS THE COASTAL WATERS. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...FLOOD WATCH THROUGH LATE TONIGHT FOR SCZ017-023-024-032-033- 039-053>056. NC...FLOOD WATCH THROUGH LATE TONIGHT FOR NCZ087-096-099-105>110. MARINE...NONE. && $$ SYNOPSIS...JDW NEAR TERM...DCH SHORT TERM...JDW LONG TERM...JDW AVIATION...43 MARINE...

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