AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 311 PM EDT MON APR 18 2011 .SYNOPSIS... HIGH PRESSURE WILL BECOME ANCHORED OVER THE WESTERN ATLANTIC THROUGH MID WEEK AS A COLD FRONT APPROACHES FROM THE NORTHWEST. THE COLD FRONT WILL MOVE ACROSS THE EASTERN CAROLINAS AND THEN OFFSHORE ON THURSDAY MORNING...BRINGING WITH IT THE CHANCE FOR SHOWERS AND THUNDERSTORMS. TEMPERATURES WILL GRADUALLY WARM UP FOR THE WEEKEND AFTER A COOLER THAN NORMAL FRIDAY AS A BERMUDA HIGH BECOMES MORE ESTABLISHED OVER THE WESTERN ATLANTIC. && .NEAR TERM /THROUGH TONIGHT/... AS OF 2:30 PM MONDAY...SEASONABLE TEMPERATURES EXPECTED THROUGH THE PERIOD. SKY SHOULD REMAIN PCLDY TO MOCLR MOST OF THE TIME. SMALL WINDOW BTW 09-12Z WHERE FCST SOUNDINGS SHOW AN EXTREMELY THIN SATURATED LAYER AROUND 200 OR 300 FT. THESE SAME FCST SOUNDINGS SHOW JUST ENOUGH WIND IN THE SAME LAYERS TO ASSUME THAT THIS MOISTURE REMAINS MIXED ENOUGH TO PRODUCE MUCH IN THE WAY OF CLOUDS. EARLIER FORECAST SOUNDINGS SHOWED SLIGHT SURFACE SATURATION AND PERHAPS SOME LIGHT FOG. MORE RECENT DATA SUGGEST THAT THIS IS LESS LIKELY. && .SHORT TERM /TUESDAY 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 /18Z MONDAY THROUGH SATURDAY/... AS OF 18Z...HIGH CONFIDENCE IN VFR THROUGH TODAY WITH A CHANCE OF SOME FOG OR STRATUS OVERNIGHT. HIGH PRESSURE WILL DRIFT OFF SHORE TODAY WHICH WHEN COMBINED WITH DEVELOPING UPPER RIDGING WILL PERMIT ONLY HIGH LEVEL CLOUDS. WINDS WILL BE LIGHT DUE TO A WEAK PG...BACKING TO THE SOUTH AND INCREASING TO AROUND 10 KTS THIS AFTN ON RETURN FLOW AROUND SURFACE HIGH PRESSURE. CONFIDENCE DECREASES OVERNIGHT DUE TO SOME FOG/STRATUS POTENTIAL. SOUTHERLY FLOW WILL CONTINUE TO ADVECT MOISTURE INTO THE COLUMN EVEN AS WINDS EASE TONIGHT. THIS COMBINED WITH MOSTLY CLEAR SKY CONDITIONS WOULD CREATE A FOG THREAT. HOWEVER...A LLJ OF 20 KTS BELOW 1 KFT WOULD FORCE MORE OF A STRATUS LAYER WHILE INHIBITING VSBY RESTRICTIONS. AN EVENT LAST WEEK THAT CREATED WIDESPREAD IFR STRATUS IS SIMILAR TO WHAT MAY OCCUR TONIGHT...HOWEVER TD/S ARE NOT AS HIGH AS LAST EVENT SO HAVE LOW CONFIDENCE IN IFR FOR NOW. HAVE OPTED TO GO WITH MVFR VSBYS AND SCT MVFR CIGS AND WILL UPDATE WITH LATER ISSUANCES. ANY FOG/STRATUS WILL BURN OFF RAPIDLY AFTER SUNRISE INLAND LEAVING SKC...AND LIFT TO A SHALLOW STRATOCU DECK AT THE COAST BUT VFR WILL BE THE RULE ON TUESDAY. 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 2:30 PM MONDAY...NOT MUCH CHANGE IN THE RATHER DIMINUTIVE SEAS THROUGH THE PERIOD. WINDS REMAIN QUITE LIGHT OUT OF THE S/SW AS THE WEST ATLANTIC HIGH RETREATS SLIGHTLY TO THE NORTH. SEA FOG STILL TOUGH TO RULE OUT BUT THE SOUTHERLY WINDS KEEP NUDGING UP THE NEAR SHORE SEA SURFACE TEMPS. GIVEN THERE HAS BEEN LITTLE CHANGE IN THE DEWPOINT FCST OF LOWER 60S THIS HAS SEEMINGLY LOWERED THE POSSIBILITY OF SEA FOG. 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. && $$