943 FXUS62 KILM 040304 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 1104 PM EDT FRI MAY 3 2013 .SYNOPSIS... HIGH PRESSURE WILL EXTEND INTO THE CAROLINAS FROM THE NORTHEAST INTO SUNDAY. AN APPROACHING LOW PRESSURE SYSTEM AND COLD FRONT WILL BRING INCREASINGLY UNSETTLED WEATHER TO THE AREA SUNDAY AND MONDAY. AN UPPER LOW WILL CONTINUE CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH THE MIDDLE OF NEXT WEEK. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... AS OF 1035 PM FRIDAY...LATEST GFS MOS GUIDANCE IS THE CLOSER OF THE VARIOUS MODEL MOS GUIDANCE IN REFERENCE TO PARTIALLY LINING UP WITH CURRENT DEWPOINTS. AS A RESULT...WILL RELY MORE HEAVILY WITH ITS OUTPUT FOR FORECASTING TONIGHTS DEWPOINTS AS WELL AS OVERNIGHT LOWS. IN FACT...CURRENT/LATEST SFC TEMPS/DEWPOINTS ARE ACTUALLY RUNNING EVEN SLIGHTLY LOWER THAN THE COOLER GFS MOS FOR THE NORTHERN 2/3RD OF THE ILM CWA. THIS BASICALLY A RESULT OF DRIER AIR FILTERING ACROSS THE AREA FROM THE NE ALONG WITH SUBSIDENCE EXHIBITED ALOFT. HAVE BACKED DOWN ON CLOUDINESS THE REMAINDER OF THIS EVENING AND CONTINUING INTO THE OVERNIGHT PERIOD. RADAR MOSAIC COVERING THE EASTERN CAROLINAS AND ADJACENT WATERS INDICATES PATCHY LIGHT RAIN/DRIZZLE JUST OFFSHORE BETWEEN CAPE FEAR AND CAPE HATTERAS...COULD POTENTIALLY DRIFT ONSHORE OVERNIGHT GIVEN THE TRAJECTORY IN THE LOWER LEVELS. PCPN AMOUNTS WILL BE QUITE LIGHT WITH A TRACE TO SEVERAL ONE HUNDREDTHS POSSIBLE. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... AS OF 3 AM FRIDAY...OMEGA BLOCK OVER THE EASTERN CONUS WILL RESULT IN UNSETTLED WEATHER FOR THE WEEKEND. HIGH PRESSURE RIDGING SOUTH FROM NEW ENGLAND UNDER MID LEVEL RIDGING SAT WILL PRODUCE A DAY QUITE SIMILAR TO TODAY. LOW LEVEL MOISTURE IN NORTHEAST FLOW WILL AGAIN LEAD TO LOW CLOUDS AND DRIZZLE WITH SOME EMBEDDED LIGHT SHOWERS. DEEP DRY AIR ALOFT AND MID LEVEL SUBSIDENCE WILL KEEP ANY ACTIVITY CONFINED TO THE LOWEST 7K FT. SO WILL CONTINUE TO CARRY SLIGHT CHC FOR MUCH OF SAT WITH AN INCREASE TO LOW CHC FOR SC LATE IN THE DAY AS DEEPER MOISTURE TO THE SOUTH STARTS TO LIFT NORTH. CLOUD COVER AND NORTHEAST FLOW WILL KEEP HIGHS BELOW CLIMO...UPPER 60S TO LOWER 70S. SAT NIGHT INTO SUN THE SURFACE AND MID LEVEL RIDGE RETREAT NORTH. MEANWHILE A STACKED CUTOFF OVER AR SLOWLY MOVES EAST. MID LEVEL FLOW VEERS TO SOUTHEAST AS THE RIDGING RETREATS...ENHANCING MOISTURE RETURN. COLD FRONT WRAPPED INTO THE STACKED LOW LIFTS INTO THE REGION FROM THE SOUTHWEST...COINCIDENT WITH ARRIVAL OF DEEPER MOISTURE. THE RESULT WILL BE SHOWERS DEVELOPING THEN EXPANDING FROM SOUTHWEST TO NORTHEAST. THERE WILL BE LOBES OF ENHANCED VORTICITY ROTATING AROUND THE SLOW MOVING CUTOFF LOW. ALTHOUGH TIMING INDIVIDUAL LOBES IS DIFFICULT THEIR ARRIVAL SHOULD LEAD TO PERIODIC INCREASES IN SHOWER ACTIVITY. ALTHOUGH CLOUDS AND PRECIP WILL BE MORE PREVALENT ON SUN THE SOUTHERLY COMPONENT TO WIND FIELD WILL RESULT IN TEMPERATURES A LITTLE WARMER ON SUN...THOUGH STILL BELOW CLIMO. LOWS WILL BE HELD NEAR CLIMO EACH NIGHT BY CLOUD COVER...THOUGH SOUTHERLY WINDS WILL HELP KEEP LOWS SLIGHTLY WARMER SUN NIGHT. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 3 PM FRIDAY...DEEP CUTOFF LOW WILL BE MAKING ITS WAY UP THROUGH THE SOUTHEAST MONDAY THROUGH WEDNESDAY. THE CENTER WILL BE DIRECTLY OVERHEAD ON TUES AND WILL REACH HATTERAS BY WEDNESDAY. BOTH THE ECMWF AND GFS WERE IN VERY GOOD AGREEMENT WITH STRENGTH AND LOCATION OF LOW WITH THE CANADIAN MODEL MUCH FARTHER WEST. THE SURFACE LOW ASSOCIATED WITH THIS SYSTEM WILL TRACK UP THROUGH THE AREA AS WELL. THIS TIGHTLY WRAPPED SYSTEM WILL THROW A COLD FRONT AROUND IT MOVING UP FROM THE SOUTHWEST WITH UNUSUALLY COOLER AIR ADVECTING IN WITH SOUTHWESTERLY FLOW AROUND THE LOW THROUGH MON EVENING INTO TUES. AS THIS FRONT MOVES UP THROUGH THE AREA ON MONDAY...EXPECT A GOOD DEAL OF PCP. THIS TIGHTLY WOUND SYSTEM WILL CONTINUE TO WRAP A FEW STRONG VORT LOBES AROUND THE CENTER AS IT MOVES OVER THE AREA THROUGH TUESDAY. H5 HEIGHTS DROP OUT ON TUES DOWN TO 560 DEM. THEREFORE EXPECT POTENTIAL FOR GREATER QPF AMOUNTS THROUGH TUESDAY. THE SYSTEM WILL CONTINUE TO WRAP AROUND MOISTURE THROUGH THURS BUT BEST LIFT AND MID LEVEL ENERGY WILL MOVE OFF TO THE NORTHEAST BY LATE WED. THEREFORE SHOULD ONLY SEE SOME LOCALIZED CONVECTION POSSIBLE ALONG SEA BREEZE BOUNDARY BY THURS AND FRI SHOULD BE THE DRIEST DAY. OVERALL EXPECT AN EXTENDED PERIOD OF UNSETTLED WEATHER WITH CLOUDS AND PCP AND BELOW NORMAL TEMPS. TUESDAY SHOULD BE THE COOLEST WITH LOW OVERHEAD...AND THEN GRADUALLY GETTING BACK TO NORMAL TEMPS BY THURS WITH SUNSHINE BACK IN THE FORECAST WITH A GREATER AMOUNT OF SUBSIDENCE AND DRIER AIR ON BACK END OF THE LOW. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... AS OF 00Z...VFR EXPECTED ACROSS THE AREA TONIGHT...WITH CONDITIONS GRADUALLY DETERIORATING TO MVFR LATE OVERNIGHT AND CONTINUING THROUGH MOST OF THE PERIOD ON SATURDAY. VFR PREVAILS THIS EVENING AS DRIER AIR HAS PUSHED IN ACROSS PORTIONS OF NC ALLOWING FOR SKIES TO CLEAR OUT IN SPOTS. ELSEWHERE... SPECIALLY ACROSS OUR SC COUNTIES...CIRRUS AND ALTO CUMULUS CLOUDS CONTINUE TO DRIFT AMONGST THE AREA. EXPECT THIS TREND TO CONTINUE INTO THE EARLY OVERNIGHT HOURS...WITH PERSISTENT NORTHEAST WINDS AOB 15 KTS AND PERIODS OF GUSTS. FCST SOUNDINGS AND TIME-HEIGHT ANALYSIS IN GOOD AGREEMENT WITH REGARDS MOISTURE RETURN OVERNIGHT...WHICH WILL ALLOW FOR LOW CIGS TO GRADUALLY MOVE ONSHORE TOWARDS MORNING. EXPECT LOWERED CIGS TO CONTINUE INTO SATURDAY AFTERNOON...WITH CHANCE OF DRIZZLE/ISOLATED LIGHT RAIN SHOWERS. EAST-NORTHEAST WINDS WILL CONTINUE...WITH SUSTAINED WINDS AOB 15 KTS AND GUSTS UP TO 25 KTS BY THE EARLY AFTERNOON HOURS. EXTENDED OUTLOOK...SLIGHT CHANCE OF SHOWERS ESPECIALLY COASTAL TERMINALS THROUGH SUNDAY. IFR/MVFR EARLY SUNDAY WITH RAIN/ISOLATED THUNDERSTORMS DEVELOPING SUNDAY EVENING PERSISTING THROUGH MONDAY. MVFR/TEMPO IFR POSSIBLE. VFR/TEMPO MVFR WITH SCATTERED SHOWERS TUESDAY. ISOLATED SHOWERS WEDNESDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1045 PM FRIDAY...PROGGED SFC PRESSURE PATTERN AND A TIGHTENED SFC PRESSURE GRADIENT...WILL YIELD NE-ENE WINDS TONIGHT...AT 20 TO 30 KT WITH FEW GUSTS UP TO GALE FORCE... ESPECIALLY OVER THE OUTER WATERS OFF CAPE FEAR AND ROMAIN. FOR THE MOST PART HAVE RELIED ON THE LATEST NAM WIND FIELDS WITH THE GFS PARTIALLY MESHED IN. AS A SIDE NOTE...LATEST 41037 BUOY WIND OBSERVATIONS ARE RUNNING QUITE HOT...IN REFERENCE TO ITS CURRENT GALE SUSTAINED WINDS...WITH WIND GUSTS HAVING SURPASSED STORM FORCE. IF THIS WERE THE CASE...CURRENT SIGNIFICANT SEAS WOULD BE WELL INTO THE DOUBLE DIGITS ACROSS THE MAJORITY OF THE ILM COASTAL WATERS. SIGNIFICANT SEAS RELIED ON THE LATEST SWAN GUIDANCE WHICH ESPECIALLY ILLUSTRATES A MORE REALISTIC NEAR SHORE SIGNIFICANT SEA HEIGHT. OVERALL...LOOKING AT A RANGE OF 4 TO 8 FT FOR THE OVERNIGHT PERIOD...EXCEPT 9 TO POSSIBLY 10 FT ACROSS THE OUTER WATERS OFF CAPE FEAR AND OFF WINYAH BAY. AVERAGE PERIODS WILL RUN 5.5 SECONDS...WITH DOMINANT PERIODS 7 TO 8 SECONDS. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 3 PM FRIDAY...GRADIENT REMAINS PINCHED SAT KEEPING NORTHEAST FLOW 20 TO 25 KT WITH SCA CONDITIONS CONTINUING. SEAS WILL REMAIN IN THE 4 TO 7 FT RANGE...MAINTAINED BY THE AFOREMENTIONED NORTHEAST FLOW. SURFACE RIDGE STARTS TO BREAK DOWN SAT NIGHT WITH WINDS VEERING TO SOUTHEAST SUN AS LOW PRESSURE AND ASSOCIATED COLD FRONT APPROACHES FROM THE SOUTHWEST. GRADIENT SLOWLY WEAKENS SUN AND SUN NIGHT WITH EAST TO SOUTHEAST WINDS DECREASING FROM 15 TO 20 KT TO 10 TO 15 KT BY THE END OF THE PERIOD. SEAS SLOWLY DECREASE SUN INTO SUN NIGHT...DROPPING TO 3 TO 6 FT BY THE END OF THE PERIOD. LONG TERM /MONDAY THROUGH WEDNESDAY/... AS OF 3 PM FRIDAY...TIGHTLY WOUND LOW PRESSURE SYSTEM WILL TRACK UP THROUGH THE SOUTHEAST MONDAY THROUGH WEDNESDAY. A COLD FRONT WILL WRAP AROUND THIS SYSTEM MOVING THROUGH THE WATERS MONDAY MORNING FROM SOUTHWEST TO NORTHEAST. THIS WILL PRODUCE A WINDS SHIFT FROM MORE EASTERLY TO SOUTHWEST. THE TIGHTENED GRADIENT FLOW WILL RELAX WITH WINDS GENERALLY S-SW 10 KTS OR LESS. SEAS WILL DROP BELOW SCA THRESHOLDS IN THE OUTER WATERS AND WILL RUN AROUND 3 TO 5 FT BUT WILL CONTINUE TO DROP THROUGH LATE MONDAY INTO TUES DOWN TO 2 TO 4 FT IN LIGHTER SOUTHERLY FLOW. OVERALL WINDS WILL REMAIN SW TO W THROUGH THE PERIOD WITH SEAS ON A SLOW DOWNWARD TREND. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SUNDAY FOR AMZ250-252-254- 256. && $$ SYNOPSIS...III NEAR TERM...DCH SHORT TERM...III LONG TERM...RGZ AVIATION...SGL