Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 181411 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 1011 AM EDT FRI APR 18 2014 .SYNOPSIS... HIGH PRESSURE WILL LINGER ACROSS THE CAROLINAS TODAY. RAIN CHANCES WILL INCREASE HEADING INTO THE WEEKEND AS A LOW PRESSURE SYSTEM OVER THE GULF COAST MOVES OFF THE SOUTHEAST UNITED STATES COAST THIS WEEKEND. A WEAK PRESSURE PATTERN WILL SETTLE OVER THE CAROLINAS FOR MUCH OF NEXT WEEK. A COLD FRONT MAY MOVE THROUGH ON TUESDAY. && .NEAR TERM /THROUGH TONIGHT/...
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AS OF 1000 AM FRIDAY...12Z SURFACE ANALYSIS SHOWS AXIS OF HIGH PRESSURE FROM THE MID-ATLANTIC STATES SOUTHWARD TO UPSTATE SC...WITH A STRONG GRADIENT IN PLACE FROM THE EASTERN CAROLINAS TO THE FLORIDA PANHANDLE. PRECIP SHIELD ASSOCIATED WITH THE GULF SYSTEM HAS ADVANCED NORTHWARD TO NEAR THE SC-GA STATE LINE. THERE ARE DIFFERENCES IN THE 06Z NAM AND GFS IN REGARDS TO HOW THIS SURFACE SYSTEM WILL EVOLVE THROUGH 12Z SATURDAY...AND THE RESULTS ARE SIGNIFICANT DIFFERENCES IN THE PREDICTED RAINFALL TOTALS. THE NAM SUGGESTS THE UPPER LOW WILL CAPTURE THE SURFACE SYSTEM OVER SOUTHERN GA LATE TONIGHT AND KEEP IT ON A MORE SOUTHERLY TRACK...ALONG WITH THE AXIS OF HIGHEST RAINFALL. THE GFS DEPICTION CONTINUES THE NORTHEASTWARD PROGRESSION OF THE SURFACE LOW ...NOT BECOMING VERTICALLY STACKED WITH THE UPPER LOW UNTIL MUCH LATER. THIS WOULD BRING THE AXIS OF HIGHEST RAINFALL MUCH CLOSER TO THE CWA. THE 00Z ECMWF IS MORE IN LINE WITH THE GFS...LENDING CONFIDENCE TO THAT SOLUTION. AS FOR THE REMAINDER OF TODAY...COOL NORTHEAST FLOW AND EXTENSIVE CLOUD COVER WILL KEEP A LID ON MAX TEMPS. EXPECT HIGHS TO REACH THE LOW TO MID 60S MOST AREAS. A FEW LIGHT SHOWERS HAVE MOVED ONSHORE THIS MORNING...AND POPS WILL TREND UP RAPIDLY BY LATE AFTERNOON INTO THE EARLY EVENING. IT APPEARS AS THOUGH THE SURFACE TROUGH AXIS WILL REMAIN OFFSHORE THROUGH THE NIGHT. THE RESULTING LACK OF DIRECT ONSHORE FLOW REDUCES THE CONCERN FOR POTENTIAL COASTAL FLOODING AND BEACH EROSION FOR THE ILM CWA.
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&& .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 330 AM FRIDAY...CUT OFF LOW PRESSURE SYSTEM WILL MOVE ACROSS THE SOUTHEAST EXITING THE COAST OF GEORGIA BY LATE SATURDAY INTO SUNDAY AND SHIFTING SLOWLY TO THE E-NE THROUGH SUN NIGHT. AT THE SAME TIME AN AREA OF HIGH PRESSURE WILL BUILD DOWN FROM CANADA INTO THE SOUTHEAST. THIS WILL HELP KEEP THE LOW SUPPRESSED FARTHER SOUTH BUT WILL NOT KEEP IT FROM SPREADING RAIN INTO THE CAROLINAS OVER THE WEEKEND. THE TROUGH AXIS SHOULD REMAIN FAR ENOUGH EAST TO KEEP A DECENT NORTHERLY FLOW ACROSS THE AREA. LOOKS LIKE BEST LIFT WILL COME THROUGH THE DAY ON SATURDAY AS LOW LEVEL WINDS INCREASE BUT MAY SEE SOME DRY AIR GET WRAPPED AROUND THE LOW INTO THE LOCAL AREA. FOR NOW...WILL GO WITH LIKELY POPS THROUGH THE FIRST HALF OF SATURDAY WITH CHC POPS LATER IN THE DAY TO ACCOUNT FOR WEAKENING LIFT AND SOME DRIER AIR WRAPPING IN. AS HIGH PRESSURE BUILDS DOWN FROM THE NORTH THE LOW WILL SHIFT ALMOST DUE EAST FARTHER OUT TO SEA THROUGH SUNDAY. MOISTURE WILL CONTINUE TO GET WRAPPED AROUND THE LOW BUT BEST LIFT WILL BE DISPLACED TO THE EAST. THEREFORE EXPECT CLOUDS AND LINGERING PCP HEADING INTO SUNDAY BUT WILL KEEP GREATEST QPF EAST. THE STIFF NORTHERLY FLOW WILL USHER IN SOME DRIER AIR THROUGH LATE SUNDAY. THE GFS IS MORE AGGRESSIVE WITH THE DRY AIR MOVING SOUTH INTO LOCAL AREA WITH PCP WATER VALUES UP TO 1.75 INCHES FOCUSED MAINLY ALONG THE COAST SAT MORNING DIMINISHING TO 1.25 INCHES BY SAT EVENING AND DOWN LESS THAN A HALF INCH AS DRY AIR MOVES IN FROM THE NORTH LATE SUNDAY INTO EARLY MONDAY. THE NAM KEEPS DRY AIR FURTHER TO THE NORTH. OVERALL EXPECT PLENTY OF CLOUDS AND PERIODS OF RAIN THROUGH MUCH OF THE WEEKEND WITH GREATEST QPF ON SATURDAY BUT LINGERING PCP INTO SUNDAY. EXPECTING A FAIRLY SIGNIFICANT RAIN EVENT...WITH QPF EVENT TOTALS IN THE 1.0 TO 2 INCH RANGE. COOL NORTHEAST FLOW WILL KEEP MAXIMUM TEMPERATURES BELOW NORMAL...WITH HIGHS IN THE MID 60S BOTH DAYS. EXTENSIVE CLOUD COVER WILL HELP KEEP MINIMUM TEMPERATURES ON THE MILD SIDE...WITH LOWS RANGING FROM THE UPPER 40S TO MID 50S BOTH DAYS. && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 330 AM FRIDAY...HIGH PRESSURE WILL WEAKEN AS IT BUILDS SOUTH INTO AREA AS LOW PRESSURE SYSTEM SHIFTS FURTHER OUT TO SEA ON MONDAY. WINDS WILL LIGHTEN AS PRESSURE GRADIENT RELAXES THROUGH MONDAY. A DRIER NORTH TO NORTHWEST FLOW WILL HELP TO CLEAR OUT THE SKY LEAVING PLENTY OF SUNSHINE. RIDGE BUILDING IN BEHIND CUTOFF LOW WITH RISING HEIGHTS THROUGH MONDAY. WINDS WILL BACK THROUGH TUES AS NORTHERN STREAM TROUGH PUSHES A COLD FRONT EAST. SLIGHT INCREASE IN MOISTURE AS RETURN FLOW SETS UP AT THE SURFACE AHEAD OF PROGRESSING FRONT. THE WINDS ALOFT REMAIN MORE WESTERLY KEEPING MORE OF A DOWNSLOPE COMPONENT TO THE FLOW...BUT HAVE INCLUDED INCREASED CHC FOR CONVECTION ON TUES AS FRONT MOVES THROUGH. BY WEDNESDAY MORNING HIGH PRESSURE WILL BUILD IN BEHIND FRONT. THE FLOW ALOFT WILL REMAIN W-NW KEEPING A WARMER DOWNSLOPE COMPONENT TO THE FLOW WITH HEIGHTS RISING INTO MID WEEK AS MID TO UPPER RIDGE BUILDS EASTWARD. OVERALL EXPECT WARMER MORE SEASONABLE WEATHER THROUGH MUCH OF THE WEEK. ONLY REAL CHC OF CLOUDS AND PCP WILL COME ON TUES WITH PASSAGE OF COLD FRONT. OTHERWISE EXPECT PLENTY OF WARM APRIL SUNSHINE WITH TEMPS REACHING UP WELL INTO THE 70S MOST DAYS. && .AVIATION /13Z FRIDAY THROUGH TUESDAY/... AS OF 12Z...DETERIORATING FLIGHT CONDITIONS THROUGH THIS TAF VALID PERIOD AS LOW PRESSURE TO THE SOUTH SPREADS MOISTURE AND RAIN NORTH ACROSS THE TERMINALS. CIGS THIS MORNING AND AFTERNOON WILL BE 4-6K OR HIGHER. THE POSSIBLE EXCEPTION WILL BE AT THE COASTAL TERMINALS MID-MORNING TO EARLY AFTERNOON WHERE THERE IS LOW-MODERATE CONFIDENCE CIGS AROUND 2.5K FT COULD OCCUR. MODELS DIFFER AS TO THE ONSET OF PRECIPITATION THIS AFTERNOON...BUT ALL AGREE THAT GENERALLY STRATIFORM RAIN WILL OCCUR THIS EVENING AND OVERNIGHT. PATCHES OF RAIN WILL DEVELOP BY 20-21Z...ONE TO THREE HOURS LATER FOR THE NORTHERN TERMINALS. DECENT ISENTROPIC LIFT SHOULD PRODUCE FAIRLY STEADY STRATIFORM PRECIP WITH A GOOD CHANCE OF MVFR CIGS THIS EVENING AND IFR OVERNIGHT. NORTHEAST WINDS WILL CONTINUE THROUGH THE PERIOD. EXTENDED OUTLOOK...EXPECT AT LEAST PERIODS OF MVFR/IFR CIGS FRIDAY EVENING AND SATURDAY. MVFR CIGS COULD LINGER WELL INTO SUNDAY. VFR ON MONDAY AND TUESDAY. && .MARINE...
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NEAR TERM /THROUGH TONIGHT/... AS OF 1000 AM FRIDAY...MORNING BUOY OBSERVATIONS ACROSS THE AREA WATERS INDICATE WIND SPEEDS IN A 10-15 KNOT RANGE NEAR SHORE...INCREASING TO A 20-25 KNOT RANGE AT 41013. SEAS WERE IN A 4-7 FT RANGE. VERY LITTLE CHANGE IN THE CURRENT CONDITIONS IS EXPECTED THROUGH THE DAY...HOWEVER AS SURFACE LOW APPROACHES FROM THE GULF OF MEXICO...WIND SPEEDS ARE EXPECTED TO INCREASE A BIT AND SEAS WILL BUILD ANOTHER FOOT OR TWO OVERNIGHT. THE SURFACE LOW IS EXPECTED TO TAKE A NORTHEAST TRACK OUT OF THE GULF...BRINGING IT TO A POSITION NEAR THE GA COAST BY EARLY SATURDAY MORNING. A FEW LIGHT SHOWERS THROUGH MID AFTERNOON WILL GIVE WAY TO WIDESPREAD RAINFALL OVER THE COASTAL WATERS DURING THE EVENING HOURS. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 330 AM FRIDAY...NORTHERLY FLOW WILL PERSIST THROUGH THE WEEKEND AS LOW PRESSURE SYSTEM MOVES FROM THE GULF COAST EAST INTO THE ATLANTIC WATERS. THE OUTERMOST WATERS MAY EXPERIENCE SOME VARIABLE WINDS AS TROUGH EXTENDS UP FROM LOW PRESSURE SYSTEM THROUGH THE OFF SHORE WATERS. MAY SEE WINDS DIMINISH SLIGHTLY AS HIGH PRESSURE RETREATS TO THE NORTHEAST ON SATURDAY BUT AS NEXT HIGH PRESSURE BUILDS IN BY LATE SATURDAY INTO SUNDAY...WINDS WILL INCREASE. AS WINDS DIMINISH SLIGHTLY SAT AFTN SEAS MAY DROP NEAR OR JUST BELOW SCA THRESHOLDS BEFORE SHOOTING UP ONCE AGAIN LATE SATURDAY THROUGH SUNDAY. OVERALL EXPECT SEAS 4 TO 6 FT THROUGH SAT BEFORE RAPIDLY RISING THROUGH LATE SAT UP TO 7 TO 9 FT. WNA HAS SEAS PEAKING UP TO 10 FT SUN MORNING AS NORTHERLY WINDS REACH 25 TO 30 KTS. WINDS AND SEAS SHOULD BEGIN TO COME DOWN BY SUNDAY NIGHT AS LOW SHIFTS FARTHER OUT TO SEA. LONG TERM /MONDAY THROUGH TUESDAY/... AS OF 330 AM FRIDAY...HIGH PRESSURE WILL WEAKEN AS IT BUILDS DOWN FROM THE NORTH BEHIND DEPARTING LOW PRESSURE SYSTEM. THEREFORE WINDS AND SEAS WILL DROP OUT THROUGH MONDAY. WINDS WILL ALSO BACK AS NEXT SYSTEM MOVES EAST TOWARD THE CAROLINAS. SHOULD SEE A MODERATE RETURN FLOW DEVELOPING AHEAD OF NEXT COLD FRONT LATE MONDAY INTO EARLY TUES. ONCE FRONT PASSES THROUGH LATE TUES INTO WED OFF SHORE FLOW WILL DEVELOP ALLOWING NEAR SHORE SEAS TO DROP OUT WHILE OFF SHORE SEAS MAY RISE A BIT. OVERALL EXPECT SEAS TO DIMINISH THROUGH MON WITH A RISE IN WINDS AND SEAS TUES INTO WED IN SW FLOW AHEAD OF FRONT AND NORTHERLY FLOW BEHIND IT HEADING INTO WED.
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&& .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SUNDAY FOR AMZ250-252-254- 256. && $$ NEAR TERM...CRM SHORT TERM...RGZ LONG TERM...RGZ AVIATION...MRR

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