AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 744 PM EDT MON APR 18 2011 .SYNOPSIS... HIGH PRESSURE WILL REMAIN ANCHORED OVER THE WESTERN ATLANTIC WATERS THROUGH MID WEEK WHILE A COLD FRONT APPROACHES FROM THE NORTHWEST. THE COLD FRONT WILL SLIDE ACROSS THE EASTERN CAROLINAS AND OFFSHORE EARLY THURSDAY...BRINGING WITH IT THE CHANCE FOR SHOWERS AND POSSIBLY THUNDERSTORMS. COOL HIGH PRESSURE FROM THE NORTH WILL RIDGE ACROSS THE AREA LATE THURSDAY THROUGH FRIDAY. TEMPERATURES WILL GRADUALLY WARM UP DURING THE WEEKEND AS THE HIGH SLIDES OFF THE EAST COAST AND SOUTHERLY FLOW DEVELOPS ACROSS THE AREA. && .NEAR TERM /THROUGH TONIGHT/... AS OF 744 PM MONDAY...SEA BREEZE DIFFICULT TO DISCERN VIA 88-D RETURNS WHICH IS USUALLY NOT THE CASE. HOWEVER...LOOKING AT SFC OBS...A DECENT GRADIENT OF DEWPOINTS EXISTS ACROSS THE COASTAL COUNTIES WITHIN THE ILM CWA. YOU HAVE MID TO UPPER 50S ACROSS THE COASTAL COUNTIES...AND 1 COUNTY INLAND...YOU HAVE LOW TO MID 40S. KNOWING THIS GRADIENT WILL GREATLY AID THE MIN TEMP FORECAST TONIGHT...WITH MID TO UPPER 50S LOWS FOR COASTAL COUNTIES...AND AROUND 50 OR LOWER 50S INLAND. PROGGED DEWPOINTS OVERNIGHT REMAIN TOO LOW TO AID SEA FOG FORMATION. BEGINNING TO GET DIFFICULT FOR THIS WX PHENOMENA WITH ADJACENT SSTS NOW IN THE MID TO UPPER 60S AT THE MOMENT. TIME HEIGHT SECTIONS FROM VARIOUS MODELS INDICATE THIN TO OCCASIONAL OPAQUE HIGH LEVEL MOISTURE TO TRAVERSE THE FA OVERNIGHT. IN ADDITION...A VERY SHALLOW DEPTH OF MOISTURE NEAR GROUND LEVEL...BEST EXHIBITED ALONG THE COAST WHERE A WEAK LOW LEVEL JET TO RESIDE. MODELS INDICATE MAINLY SUBSIDENCE ALOFT TONIGHT INTO TUESDAY...AND THEREFORE AM INCLINED TO HOLD OFF WITH THE INCLUSION OF A LOW DECK OF STRATUS/STRATUS FRACTUS WITHIN THIS 50MB DEPTH OF INCREASED MOISTURE. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... AS OF 3:00 PM MONDAY...TEMPERATURES WILL RISE A BIT ABOVE AVERAGE MOST PLACES ON TUESDAY AS HIGH PRESSURE BECOMES ESTABLISHED OVER THE WESTERN ATLANTIC...BRINGING A WARM SOUTHERLY FLOW TO THE REGION. HIGH TEMPERATURES WILL RANGE FROM THE 70S ALONG THE COAST TO THE MID 80S INLAND...WITH LOWS IN THE 60S OVERNIGHT. MODEL SOUNDINGS AND SATELLITE LOOPS SUGGEST WE WILL SEE A GOOD BIT OF CIRRUS ON AND OFF THROUGH THE DAY AND INTO THE NIGHT. BREEZY AND GUSTY DAY WEDNESDAY AS GRADIENT TIGHTENS IN ADVANCE OF A COLD FRONT APPROACHING FROM THE NW. INCREASING SWLY FLOW WILL FURTHER HELP RAISE MAXIMUM TEMPERATURES INTO THE MID TO UPPER 80S MOST LOCATIONS EXCEPT IN THE 70S ALONG THE COAST. SLIGHT CHANCE FOR CONVECTIVE PRECIPITATION AFTER MIDNIGHT AS COLD FRONT MOVES ACROSS THE FORECAST AREA. ALTHOUGH THERE WILL BE SOME DECENT UPPER SUPPORT IN THE FORM OF A VIGOROUS SHORT WAVE...LOW LEVEL MOISTURE SEEMS TO BE LACKING...SO NOT TOO EXCITED AT THE PROSPECTS FOR SIGNIFICANT QPF AT THIS POINT. TEMPERATURES WILL AGAIN BE ABOVE AVERAGE OVERNIGHT...LOW 60S INLAND TO MID 60S ALONG THE COAST. && .LONG TERM /THURSDAY THROUGH MONDAY/... AS OF 3:00 PM MONDAY...PERSISTENT FEATURES WILL BE FLAT RIDGING ALOFT AND SFC HIGH PRESSURE OFF THE COAST. THIS PATTERN WILL BE VERY SIMILAR TO OUR SUMMER BERMUDA HIGH...WITH THE EXCEPTION OF A COLD FRONT DROPPING SOUTH ACROSS THE AREA THURSDAY...AND PROVIDING A SLIGHTLY COOLER ONSHORE FLOW FOR THU NIGHT AND FRI. ONLY LEGITIMATE CHANCE FOR PRECIP IS THURSDAY INTO FRIDAY WITH THIS FRONT...AND WILL BE AMPLY COVERED BY A LOW CHANCE GIVEN FAIRLY DRY WESTERLY FLOW ALOFT. TEMPS NEAR NORMAL THURSDAY NIGHT AND FRIDAY...BUT OTHERWISE 5-10 DEGREES ABOVE CLIMO EACH DAY. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... AS OF 23Z...MODERATE TO HIGH CONFIDENCE IN A VFR FORECAST FOR THE VALID TAF PERIOD. ONLY REAL UNCERTAINTY HINGES ON THE POTENTIAL FOR FOG/STRATUS TOWARD DAYBREAK. GIVEN THE LIMITED DEPTH OF LOW- LEVEL MOISTURE...AND 1000 MB WINDS HOLDING ON AROUND 15-20 KT THROUGH THE NIGHT...THE POTENTIAL FOR STRATUS OR FOG APPEARS QUITE LIMITED. IF WE SEE IT ANYWHERE IT WOULD BE IN MYR/CRE WHERE THE WIND FIELD IS WEAKEST BY DAYBREAK AND THERE IS MORE MOISTURE AVAILABLE. LIGHT SSW WINDS OVERNIGHT WILL PICK BACK UP TO AROUND 10 KT WHEN THE MORNING INVERSION BREAKS. SLIGHTLY STRONGER WINDS WITH GUSTS NEAR 20 KT IN THE COASTAL TERMINALS BEGINNING 18-19Z WITH THE SEABREEZE. EXTENDED OUTLOOK...LOW CONFIDENCE IN FOG WEDNESDAY MORNING. LOW CONFIDENCE IN SHOWERS WITH ISOLATED THUNDERSTORMS THURSDAY. SHOWERS MAY PERSIST FRIDAY AND SATURDAY AS WELL. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 744 PM MONDAY...THE SFC RIDGE AXIS WILL EXTEND WSW ACROSS THE AREA WATERS FROM THE WESTERN ATLANTIC HIGH OVERNIGHT...AND BEGIN TO GET SUPPRESSED SOUTHWARD DURING TUESDAY. THE SFC PG WILL BE SOMEWHAT RELAXED...HOWEVER A WEAK SSW LOW LEVEL JET WILL PARTIALLY INFLUENCE THE WATERS AFTER MIDNIGHT THRU DAYBREAK TUE. SSTS REMAIN COOL ENOUGH TO PREVENT THE FULL EFFECTS OF THE LOW LEVEL JET...AND THUS WILL CONTINUE THE S WIND AROUND 10 KT FORECAST. A PERSISTENT 2-3 FOOT 8-9 SECOND PERIOD EASTERLY SWELL WILL CONTINUE TO AFFECT THE WATERS OVERNIGHT...WITH A RELATIVELY NEGLIGIBLE 1 FOOT LOW PERIOD WIND WAVE. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3:00 PM MONDAY...HIGH PRESSURE BECOMES ESTABLISHED OVER THE WESTERN ATLANTIC ON TUESDAY...BRINGING A GRADUALLY INCREASING SOUTHERLY FLOW TO THE WATERS...FROM AROUND 10 KTS TUESDAY MORNING TO 15 KTS WEDNESDAY MORNING. SEAS WILL INCREASE FROM 2 TO 3 FT TO 3 TO 4 FT DURING THAT PERIOD. WINDS WILL VEER TO THE SW WEDNESDAY IN ADVANCE OF A COLD FRONT WHICH SHOULD BE LINED UP ALONG THE COAST BY THE END OF THE SHORT TERM. SEAS WILL MAINTAIN IN THE 3 TO 4 FT RANGE. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 3:00 PM MONDAY...COLD FRONT DROPPING THROUGH THE AREA ON THURSDAY...AND A BIT OF A LOW-CONFIDENCE FORECAST DEPENDENT ON HOW MUCH OF A BACKDOOR PRESENTATION THE FRONT TAKES OUT OVER THE WATERS. WILL INITIALIZE WITH SW AND END UP ENE BY THE END OF THE DAY. FAIRLY CONFIDENT IN VEERING WINDS OVER LAND...BUT THINK THAT THE SEABREEZE PROCESSES WILL MAKE FOR MORE OF A BACKING OVER THE WATER. DECENT ENE SURGE THURSDAY NIGHT COULD PUMP WINDS UP TO 15-20 KT...AND WHEN WE THROW IN A 3 FT ESE SWELL THAT COULD LEAD TO MARGINAL SCA SEAS. SURGE FADES THROUGH THE DAY ON FRIDAY...AND THEN WINDS VEER TO SE FRIDAY NIGHT AND THEN SOUTH ON SATURDAY AS WE RETURN TO A MORE BENIGN PATTERN QUITE SIMILAR TO THE TYPICAL BERMUDA HIGH. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$