Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 220531 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 131 AM EDT FRI AUG 22 2014 .SYNOPSIS... HOT AND HUMID CONDITIONS WILL PERSIST THROUGH FRIDAY. A COLD FRONT WILL SAG SOUTHWARD ACROSS THE AREA FRIDAY NIGHT AND SATURDAY...BRINGING A HIGHER RISK FOR SHOWERS AND THUNDERSTORMS. SURFACE HIGH PRESSURE WILL FOLLOW FROM THE NORTH EARLY NEXT WEEK BRINGING MORE COMFORTABLE TEMPERATURE AND HUMIDITY LEVELS. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 1000 PM THURSDAY...THUNDERSTORMS SURGED SOUTHEASTWARD INTO NORTHERN NORTH CAROLINA MORE QUICKLY THAN EXPECTED...BUT A DRIER AIRMASS THROUGHOUT THE 950-800 MB LAYER AND INCREASING DISTANCE FROM THE UPPER DISTURBANCE MEANS THESE STORMS ARE DRYING UP. IT REMAINS POSSIBLE AS THE UPPER DISTURBANCE REACHES SE NORTH CAROLINA LATE TONIGHT THAT ISOLATED SHOWERS COULD REDEVELOP AS SHOWN ON THE 23Z HRRR RUN. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS... CONVECTION ALONG THE COAST HAS DIED AWAY LEAVING A MERGED OUTFLOW/SEABREEZE BOUNDARY EASILY DISCERNIBLE ON RADAR IMAGERY FROM NEAR ELIZABETHTOWN TO DILLON...MARION...AND INTO WESTERN GEORGETOWN COUNTY. VISIBLE SATELLITE IMAGERY SHOWS NO CUMULUS CLOUDS ALONG THE BOUNDARY SUGGESTING LIFT IS INSUFFICIENT TO PUSH PARCELS TO THEIR LCL...LET ALONE THEIR LFC! DRY WEATHER IS ANTICIPATED THROUGH THE EVENING HOURS WITH JUST SOME CIRRUS IN A NORTHWEST FLOW ALOFT. IN THE UPPER LEVELS HIGH PRESSURE IS CENTERED OVER NEW ORLEANS WHILE A SERIES OF SHORTWAVES HELPS AMPLIFY A TROUGH OFF THE NEW ENGLAND COAST. ONE SUBTLE SHORTWAVE TROUGH MOVED OFF THE CAROLINA COAST A FEW HOURS AGO...WHILE A SECOND DISTURBANCE UPSTREAM ACROSS SOUTHWESTERN VIRGINIA IS HELPING INDUCE THUNDERSTORM ACTIVITY THERE. MODELS CONFIRM SIMPLE LINEAR EXTRAPOLATION BRINGING THIS NEXT UPPER DISTURBANCE SOUTHEASTWARD AND ACROSS SOUTHEASTERN NORTH CAROLINA EARLY FRIDAY MORNING...5-8 AM EDT. LAPSE RATES ALOFT WILL CERTAINLY BE STEEP ENOUGH TO SUPPORT CONVECTION...HOWEVER RATHER DRY AIR LURKING WITHIN THE 950-800 MB LAYER SHOULD MAKE IT TOUGH FOR MUCH CONVECTION TO SURVIVE THIS FAR SOUTHEASTWARD. LOWS TONIGHT SHOULD REACH 73-76 FOR MOST AREAS...WITH 500-1000 FOOT WIND SPEEDS ARGUING FOR ONLY A SMALL POTENTIAL FOR FOG. && .SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/... AS OF 300 PM THURSDAY...THE STRONG MID AND UPPER LEVEL RIDGE WILL BEGIN TO RETROGRADE...ALLOWING A TROUGH OFF THE EAST COAST TO DIG SOUTHWARD. THIS WILL ALLOW A COLD FRONT TO OUR NORTH TO SAG SOUTHWARD AND WE EXPECT THIS FRONT TO SLOWLY BACKDOOR THROUGH THE FORECAST AREA FRI NIGHT AND SAT. SHORTWAVES TOPPING THE AMPLIFIED RIDGE MAY SERVE TO ENHANCE THE COVERAGE AND INTENSITY OF CONVECTION AND ALTHOUGH TIMING IS DIFFICULT AT THIS JUNCTURE... WILL SHOW POPS TRENDING TO A HIGHER PROBABILITY SAT AND SAT NIGHT. THE CONVECTION WHILE STILL GENERALLY SLOW MOVING...SHOULD PICK UP THE PACE THIS PERIOD AS COLUMNAR WINDS INCREASE SLIGHTLY. FRI SHOULD BE THE WARMEST DAY OF THE TWO AND THUS THE MOST UNCOMFORTABLE. HOWEVER...THERE APPEARS TO AGAIN BE ENOUGH DRIER AIR IN THE MID LEVELS SO THAT WHEN MIXING BECOMES DEEPER MIDDAY AND THROUGH THE AFTERNOON...DEWPOINTS WILL AGAIN DROP...WITH MANY AREAS AWAY FROM THE IMMEDIATE COAST DROPPING TO THE UPPER 60S AND LOWER 70S. THUS...EVEN WITH THE INTENSE HEATING...TEMPS IN THE MID AND UPPER 90S FRI...IT WILL BE A STRUGGLE TO MEET HEAT ADVISORY CRITERIA IN MOST LOCATIONS. THE BEST CHANCE FOR MARGINALLY MEETING CRITERIA WILL BE ACROSS THE SOUTHERN PEE DEE AND PERHAPS PORTIONS OF THE GRAND STRAND. AT THIS TIME...WILL HIGHLIGHT THE HEAT AND HUMIDITY IN THE HWO...BUT REFRAIN FROM ISSUING AN ADVISORY. MORE WIDESPREAD CLOUDINESS DEVELOPING SAT SHOULD HELP TO KEEP TEMPS DOWN A CATEGORY OR SO...WILL GO FOR WIDESPREAD LOWER TO MID 90S. THE SEABREEZE WILL MOVE INLAND BOTH DAYS...MORE SO ON SAT... KEEPING DAYTIME HIGHS LOWEST ALONG THE IMMEDIATE COAST. NIGHTTIME VALUES ACROSS THE FORECAST AREA WILL BE A LITTLE ABOVE CLIMATOLOGY FOR LATE AUG. && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 300 PM THURSDAY...MID TO UPPER LEVEL PATTERN AMPLIFIES AS THE RIDGE BUILDS UP FROM THE MISSISSIPPI VALLEY INTO NEW ENGLAND THROUGH EARLY NEXT WEEK AND THEN EXPANDS EASTWARD OVER THE SOUTHEAST COAST THROUGH THE WEEK. THIS WILL HELP TO PUSH COLD FRONT FARTHER SOUTH THROUGH SUNDAY AS SURFACE HIGH BUILDS DOWN FROM THE NORTHEAST THROUGH THE WEEK. EXPECT LINGERING CLOUDS AND SHOWERS ON SUNDAY TO SHIFT SOUTH THROUGH THE DAY AS COLD FRONT MOVES SOUTH. THEN THE BUILDING RIDGE SHOULD HELP TO SUPPRESS ANY WIDESPREAD OR STRONG CONVECTION THROUGH MUCH OF THE WEEK PRODUCING A QUIETER WEATHER PERIOD. TEMPS WILL BE BACK DOWN TO NORMAL BEHIND COLD FRONT WITH HIGHS BETWEEN 85 AND 90 MOST DAYS AND OVERNIGHT LOWS BETWEEN 65 AND 70. AS FOR THE TROPICAL SYSTEM APPROACHING THE WINDWARD ISLANDS MENTIONED PREVIOUSLY...THE MODELS REMAIN FAIRLY INCONSISTENT AS TO THE EXACT TRACK OR INTENSITY. THE GFS WAS TRACKING IT UP INTO THE GULF COAST A FEW DAYS AGO AND THEN HAS PROGRESSIVELY SHIFTED EAST NOW SHOWING MORE OF A TRACK UP THROUGH THE ATLANTIC WATERS EAST OF COASTAL CAROLINAS LATER NEXT WEEK. THE ECMWF HAS BEEN THE FARTHEST EAST AND FASTEST MODEL WITH THE SYSTEM. AT THIS POINT DECENT SWELLS MAY REACH OUR COASTAL WATERS BY MID WEEK BUT AS FAR AS WEATHER...TOO MUCH UNCERTAINTY STILL EXISTS. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/...
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AS OF 06Z...VFR CONDITIONS MAY GIVE WAY TO PATCHES OF MVFR VSBYS OVERNIGHT AS CALM AND HUMID CONDITIONS SUPPORT SOME PATCHY MVFR BR. ELSEWHERE...EXPECT THICKENING MID/HIGH CLOUDS TO KEEP VSBYS FROM DROPPING BELOW MVFR. VSBYS WILL IMPROVE TO VFR SOON AFTER 12Z WITH WNW WINDS AROUND 5 KTS THIS MORNING. AS THE SEA BREEZE MOVES ONSHORE...WINDS ALONG THE COAST WILL BECOME S-SW AROUND 10 KT. NOT EXPECTING MUCH IN THE WAY OF AFTN CONVECTION OTHER THAN SOME ISOLATED SEA BREEZE STORMS POSSIBLY DEVELOPING AFTER 18Z. WILL INCLUDE VCTS FOR THE COASTAL SITES ATTM...EVENTHOUGH CONFIDENCE IS NOT AS HIGH LIKE PREVIOUS DAYS. THIS MAINLY DUE TO THE INFLUENCE OF THE UPPER HIGH PRESSURE RIDGE WHICH TENDS TO SUPPRESS CONVECTION. EXTENDED OUTLOOK...CHC AFTERNOON/EVENING SHRA/TSRA THROUGH SUNDAY. EXPECT VFR MON/TUE WITH HIGH PRESSURE OVER THE EAST COAST.
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&& .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1000 PM THURSDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE FORECAST. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS... THE PRESSURE PATTERN OVER THE CAROLINAS IS QUITE WEAK THIS EVENING. LOW PRESSURE IS LOCATED ACROSS THE PLAINS STATES AND HIGH PRESSURE IS WELL OFFSHORE. AN OLD STATIONARY FRONT HAS DECAYED TO A SIMPLE LOW PRESSURE TROUGH INLAND. THIS BOUNDARY HAS MERGED WITH TODAY`S SEABREEZE AND EARLIER THUNDERSTORM OUTFLOWS AND IS NOW LOCATED JUST EAST OF INTERSTATE 95. SOUTHWEST WINDS AROUND 10 KNOTS SHOULD VEER A LITTLE MORE WESTERLY OVERNIGHT...WITH SEAS AROUND 2 FEET. THE POTENTIAL FOR FURTHER THUNDERSTORM ACTIVITY IS RATHER LOW...HOWEVER AN UPPER LEVEL DISTURBANCE CURRENTLY PRODUCING THUNDERSTORMS ACROSS SOUTHWESTERN VIRGINIA WILL SWEEP SOUTHEASTWARD AND MAY AFFECT THE CAPE FEAR AREA BEGINNING AROUND 5 AM. SHORT TERM /FRIDAY THOUGH SATURDAY NIGHT/... AS OF 300 PM THURSDAY...SW WINDS WILL PERSIST INTO FRI NIGHT. A COLD FRONT WILL SLOWLY SAG SOUTH ACROSS THE WATERS LATE FRI NIGHT AND SAT AND THIS WILL SERVE TO SHIFT WINDS TO A MORE NORTHERLY DIRECTION AND THEN MORE EASTERLY SAT AFTERNOON AS THE SEABREEZE DEVELOPS. WINDS SAT NIGHT WILL BACK TO NE AND INCREASE AS A MODEST SURGE DEVELOPS SOUTHWARD ACROSS THE WATERS. HIGHEST WIND SPEEDS WILL BE FRI AFTERNOON AND NIGHT AND THEN AGAIN OVERNIGHT SAT...UP TO AROUND 15 KT. SEAS WILL BE 2 TO 3 FT WITH SOME 4 FT SEAS DEVELOPING FRI NIGHT ACROSS THE OUTERMOST WATERS. THESE 4 FT SEAS WILL BECOME MORE WIDESPREAD FROM NORTH TO SOUTH LATE SAT NIGHT. LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 300 PM THURSDAY...HIGH PRESSURE WILL BUILD DOWN BEHIND COLD FRONT FROM THE NORTHEAST THROUGH EARLY NEXT WEEK. THIS WILL PRODUCE A NORTHEAST SURGE IN WINDS WITH PERSISTENT NE FLOW UP TO 15 KTS CONTINUING THROUGH MONDAY. MAY SEE AN INCREASE IN WINDS AND SEAS BY TUESDAY AS A TROPICAL SYSTEM BEGINS TO MAKE PROGRESS NORTH HELPING TO TIGHTEN THE GRADIENT AND INCREASE WINDS AND SWELLS. FOR NOW WILL SHOW INCREASE IN SEAS UP TO 4 TO 5 FT LATE SUNDAY INTO MONDAY AND THEN FURTHER INCREASE POSSIBLY UP TO ADVISORY LEVELS BY MID WEEK. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...RJD NEAR TERM...MJC SHORT TERM...RJD LONG TERM...RGZ AVIATION...DCH/BJR

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