AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 744 AM EDT THU AUG 18 2011 .SYNOPSIS... BERMUDA HIGH PRESSURE WILL REASSERT ITSELF TODAY AND PERSIST THROUGH EARLY NEXT WEEK. THIS WILL RAISE HUMIDITY LEVELS AND BRING A SLIGHTLY BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS. A COLD FRONT WILL MOVE ACROSS THE AREA TUESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 730 AM THURSDAY...LATEST KLTX 88-D RADAR TRENDS INDICATE NOCTURNAL SHRA/TSRA STILL A THREAT ALONG THE IMMEDIATE COAST AND WILL CONTINUE WITH POPS. MUCH OF THE CONVECTION OVER THE WATERS IS CLOSER TO WHERE THE INVERTED COASTAL TROF RESIDES...WHICH EXTENDS FROM CAPE HATTERAS NC SOUTHWARD TO OFF JACKSONVILLE FL. SOME OF THIS ACTIVITY WILL CONTINUE TO REACH THE IMMEDIATE COAST BEFORE QUICKLY DISSIPATING AS IT FURTHER TRACKS ONSHORE AND INLAND. THE DIURNALLY INDUCED CONVECTION OVER LAND WILL QUICKLY COMMENCE ONCE THE DAYS INSOLATION COMMENCES. THE NAM MODEL SEEMS TO HAVE A BETTER FEEL WITH REGARD TO THE COASTAL TROF AND PCPN POTENTIAL...ESPECIALLY WITH WHAT IS OCCURRING AT THE MOMENT. WITH THIS SAID...HAVE INCREASED POPS AND CLOUD COVERAGE...ESPECIALLY ACROSS THE COASTAL COUNTIES. THE ACTIVITY OVER THE COASTAL WATERS SHOULD DIMINISH SOME BY LATE THIS MORNING. HOWEVER...THE NAM AND TO A LESSER DEGREE THE GFS...INDICATE A WEAK 5H S/W TROF THAT DROPS ESE AND PARTIALLY AFFECTS THE AREA THIS AFTERNOON AND NIGHT. THE DYNAMICS FROM THIS FEATURE COULD INTERACT WITH A WEAK SEA BREEZE AND PRODUCE MORE THAN JUST ISOLATED CONVECTION BY MIDDAY TODAY THROUGH THIS AFTERNOON. THE BEST PCPN COVERAGE WILL BE ACROSS THE COASTAL COUNTIES AND ADJACENT WATERS. OVERALL...LOOK FOR POPS RANGING FROM 0-10 PERCENT WEST OF I-95...UP TO 30 TO 40 POPS ALONG THE COAST. HAVE ALSO ADVERTISED A BIT MORE CLOUD COVERAGE ACROSS THE ENTIRE CWA...WHICH HAS RESULTED IN MAX TEMPS LOWERED BY 1 TO POSSIBLY 3 DEGREES FROM THE PREVIOUS FORECAST. HAVE ALSO INCREASED MINS TONIGHT BY A FEW DEGREES DUE TO PARTIAL CLOUD COVERAGE. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 3 PM THURSDAY...BERMUDA HIGH EXTENDS BACK TOWARDS THE CAROLINAS WHILE A TROUGH BECOMES MORE PRONOUNCED INLAND. IN THE MID TO UPPER LEVELS A FEW SHORTWAVES MOVE THROUGH FRI AND SAT BEFORE FLOW. THIS MAY HELP TO ENHANCE AFTN CONVECTION ALONG THE SEA BREEZE BOUNDARY BOTH FRI AND SAT BUT WILL DEPEND ON TIMING OF THESE FEATURES. NAM SHOWING PCP WATER VALUES UP CLOSE TO 2 INCHES ALONG SEA BREEZE CONVERGENT BOUNDARY AS IT PUSHES INLAND FRI AFTN...BUT A DECENT N-NW STEERING FLOW SHOULD PUSH THE CLOUDS AND SHOWERS BACK TOWARD THE COAST LATE DAY. SAT LOOKS LIKE MORE OF THE SAME BUT MAY SEE MORE IN THE WAY OF CONVECTION INLAND GETTING PUSHED TOWARD THE COAST INTO SAT EVENING. OVERALL A MORE WARM AND HUMID AIR MASS WITH BETTER CHC OF AFTN SHWRS/TSTMS. TEMPS WILL REACH ABOVE NORMAL AGAIN WITH HEAT INDICES REACHING UP OVER 100 IN PLACES SAT AND SUN. 850 TEMPS WILL BE ON THE RISE REACHING ABOUT 20C BY LATE SUN IN A W-SW FLOW THROUGH THE LOW LEVELS OF THE ATMOSPHERE. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 3 AM THURSDAY...WARM MOIST SOUTHERLY FLOW WILL CONTINUE SUN INTO MON ON WESTERN PERIPHERY OF BERMUDA HIGH AS PIEDMONT TROUGH REMAINS PRONOUNCED INLAND ON SUN. BY LATE MON INTO TUES SHORTWAVE MAY PUSH A COLD FRONT THROUGH. LATEST MODEL RUNS KEEP FRONT LINGERING AROUND TUES INTO WED INSTEAD OF PUSHING DRIER AIR IN. WILL HAVE TO FOLLOW CLOSELY TO SEE HOW THIS PANS OUT. ALSO MODELS CONTINUE TO SHOW A TROPICAL SYSTEM SOMEWHERE IN THE VICINITY OF FLORIDA BY NEXT FRI. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... AS OF 12Z...CONVECTION WILL REMAIN MOSTLY OFFSHORE THIS MORNING...FUELED BY MID TO HIGH 80S WATER TEMPS. LOOK FOR ISOLATED TO SCATTERED CONVECTION TO FIRE ALONG THE SEA BREEZE BOUNDARY BEGINNING AROUND NOON. WENT WITH VCSH AT THIS TIME...BUT MAY HAVE TO AMD TO ADD TEMPO GROUP FOR SHOWERS AT THE COASTAL TERMINALS. LIGHT AND VARIABLE WINDS THIS MORNING WILL BECOME EAST SOUTHEAST WITH THE RESULTANT. WILL EVALUATE POTENTIAL FOR MORNING FOG ON THE NEXT SET OF TAFS. EXTENDED OUTLOOK...FOG POSSIBLE FRIDAY MORNING. SCATTERED AFTN THUNDERSTORMS POSSIBLE EACH DAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 745 AM THURSDAY...NOT A CLEAR CUT WIND FORECAST DUE TO THE COASTAL TROF OVER THE ATLANTIC WATERS PARALLELING THE CAROLINA COASTS. HAVE STAYED CLOSER TO THE NAM WITH REGARD TO THIS FEATURE WHICH BASICALLY FLUCTUATES THE NE-SW TROF AXIS EITHER JUST EAST AND OFFSHORE...OR PARTIALLY ACROSS THE WATERS. THIS WILL PRODUCE WIND DIRECTIONS RANGING FROM NE-E DURING THE MORNING...ESE-SSE DURING THE AFTERNOON AND EVENING. LACK OF A PRESSURE GRADIENT WILL YIELD WIND SPEEDS AROUND 10 KT...EXCEPT 10-15 KT NEAR THE IMMEDIATE COAST DUE TO THE AFTERNOON/EVENING SEA BREEZE CIRCULATION. SEAS GENERALLY IN THE 2 TO 3 FOOT RANGE...WHICH INCLUDES ROUGHLY A 1 FOOT ESE 8-10 SECOND PERIOD GROUND SWELL. SHRA/TSRA ACTIVITY WILL BE MORE PRONOUNCED DURING THE PREDAWN HOURS THIS MORNING UP TO MID-MORNING...AND POSSIBLY INCREASED ACTIVITY LATER THIS AFTERNOON AND NIGHT DUE TO THE DYNAMICS FROM A MID LEVEL S/W TROF. SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 3 AM THURSDAY...SOUTHWESTERLY FLOW ON WESTERN PERIPHERY OF BERMUDA HIGH BECOMES SLIGHTLY STRONGER BY END OF THE PERIOD...BUT OVERALL FLOW DOMINATED BY THE LAND/SEA BREEZE. THEREFORE EXPECT MORE OF AN INCREASED ON SHORE FLOW EACH AFTN AS WINDS BACK TO THE SSW. A WESTERLY COMPONENT ALOFT MAY HELP TO ENHANCE OFF SHORE FLOW OVERNIGHT AND MAY SEE SOME SHWRS/TSTMS PUSH OFF SHORE IN THE EVENINGS. WITH WINDS REMAINING 10 KTS OR LESS EXPECT SEAS TO REMAIN 3 FT OR LESS. LONG TERM /SUNDAY THROUGH MONDAY/... AS OF 3 AM THURSDAY...SLIGHTLY STRONGER S-SW FLOW WILL PERSIST THROUGH THE PERIOD AROUND BERMUDA HIGH. SEAS WILL BUILD A LITTLE TOWARD THE END OF THE PERIOD AS GRADIENT TIGHTENS AS COLD FRONT APPROACHES WITH SW WINDS PICKING UP NEAR 15 KTS. THIS SHOULD HELP TO PUSH SEAS UP CLOSER TO 3 TO 4 FT BY MON NIGHT INTO TUES. OTHERWISE SEAS 3 FT OR LESS SUN INTO MON. WINDS WILL BACK SLIGHTLY EACH AFTERNOON BECOMING MORE ON SHORE AS SEA BREEZE DEVELOPS. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$