AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 220 PM EDT MON APR 18 2011 .SYNOPSIS... HIGH PRESSURE WILL MOVE PROGRESSIVELY OFFSHORE AND BECOME ANCHORED OFFSHORE OF THE SOUTHEAST U.S. COAST. A COLD FRONT WILL MOVE ACROSS THE AREA LATE IN THE WEEK. THIS BOUNDARY WILL QUICKLY YIELD TO BERMUDA HIGH PRESSURE OVER THE WEEKEND. && NEAR TERM/THROUGH TONIGHT/... AS OF 230 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 AM MONDAY...500MB RIDGE WILL BUILD SLIGHTLY TUESDAY AND WEDNESDAY WITH THE HEAT INCREASING POSSIBLY INTO THE UPPER 80S INLAND WEDNESDAY AFTERNOON. MET NUMBERS ARE THE WARMEST AND APPEAR TO BE A BIT ON THE HIGH SIDE WITHOUT A DOWNSLOPING FLOW. A STRONG SHORTWAVE RIDING ACROSS THE GREAT LAKES WILL ALLOW HEIGHTS TO FALL AND MOVE A FRONT TO THE DOORSTEP BY THE END OF THE PERIOD. HAVE ADDED SLIGHT CHANCE POPS TO THE NORTHWESTERN ZONES FOR LATE WEDNESDAY/ EARLY THURSDAY. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 3:00 AM MONDAY...MAIN FEATURES REMAIN IN PLACE REGARDING THE EXTENDED PERIOD WITH A COLD FRONT MOVING ACROSS THURSDAY LINGERING JUST SOUTH INTO FRIDAY. HAVE SOLID POPS FOR THURSDAY INTO THE EVENING TO ADDRESS ANY INHERENT TIMING ISSUES. MEDIUM RANGE MODELS ARE NOW ADVERTISING MORE TROUGHING OUT WEST THAN PREVIOUS CYCLES. THIS INCREASES THE CHANCES OF A WARM AND DRY WEEKEND FOR OUR REGION AS BERMUDA HIGH PRESSURE DEVELOPS. FOR NOW THE UPCOMING WEEKEND LOOKS DRY AND SEASONABLE REGARDING TEMPERATURES. && .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 AM MONDAY...SOUTHWEST FLOW WILL PICK UP STEAM THROUGH THE PERIOD FROM 10-15 KNOTS TO NEAR 20 KNOTS BY WEDNESDAY AFTERNOON. THIS COURTESY OF AN INCREASING GRADIENT AS A FRONT MOVES CLOSER FROM THE NORTHWEST. THE LATEST SWAN SEAS INCREASE FROM 2-4 FEET TO 3-5 FEET BY THE END OF THE PERIOD. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 3:00 AM MONDAY...COLD FRONT IS KNOCKING ON THE DOOR OF THE COASTAL WATERS INITIALLY AS A SOUTHWEST FLOW CONTINUES. THIS FLOW WILL BACK TO THE NORTHEAST BY THURSDAY EVENING ACROSS ALL WATERS AS THE BOUNDARY SLIPS SOUTH. THERE COULD BE A SURGE OR TWO OF STRONGER WINDS WITH THIS FLOW BUT ALL BUT IMPOSSIBLE TO TIME THIS FAR OUT. HAVE MAINTAINED A RANGE OF 10-15 KNOTS. THE FLOW WILL KICK UP SEAS TO 3-5 FEET. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$