000 FXUS62 KILM 242015 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 315 PM EST TUE NOV 24 2009 .SYNOPSIS... COOL AND DAMP CONDITIONS WILL CONTINUE THROUGH TONIGHT AS A WEDGE OF HIGH PRESSURE PERSISTS ALONG THE EAST COAST. AN AREA OF LOW PRESSURE WILL PASS OFFSHORE BY WEDNESDAY NIGHT. A STRONG COLD FRONT LATE THURSDAY WILL BE FOLLOWED BY CHILLY HIGH PRESSURE EARLY IN THE WEEKEND. RETURN FLOW WILL BRING BACK MILDER AIR BEGINNING SUNDAY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... AS OF 3 PM TUESDAY...HIGH PRESSURE REMAINS RATHER DIRTY OVER THE SOUTHEAST AS MOISTURE REMAINS TRAPPED BELOW 2000 FEET. EARLIER DRIZZLE IS PRETTY MUCH GONE AS CEILINGS LIFTED SLIGHTLY...BUT THE SHALLOW STRATUS PERSISTS. NOT ENOUGH GRADIENT TO MIX DOWN ANY OF THE DRIER AIR...SO EXPECT LITTLE CHANGE TO THESE CONDITIONS OVERNIGHT. MIN TEMPS WILL BE VERY CLOSE TO CURRENT DEWPOINTS...SO WOULD EXPECT SOME FOG OVERNIGHT...BUT NOTHING OF THE DENSE VARIETY. VISIBILITIES IN THE 1-2 MILE RANGE WILL BE WORTHY OF MENTION IN THE ZONES. HAVE GONE ABOUT A CATEGORY ABOVE GUIDANCE FOR TEMPS AS THE MODELS HAVE NOT HANDLED THIS SITUATION WELL SO FAR. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... AS OF 3 PM TUESDAY...SURFACE LOW TAKING SHAPE OVER THE NORTHERN GULF OF MEXICO WILL REDEVELOP OFF THE EAST COAST OF FL WED MORNING. THE LOW WILL TRACK NORTHEAST...ALONG WEAK COASTAL TROF...PASSING EAST OF THE CAPE FEAR REGION LATE WED NIGHT INTO THU. 12Z NAM/GFS SPREAD SOME PRECIP OVER THE IMMEDIATE COAST TOMORROW AFTERNOON/EVENING IN THE ONSHORE FLOW AHEAD OF THE LOW. THEY ALSO DEVELOP A LITTLE BIT OF ISENTROPIC LIFT IN THE EVENING...WHICH MAY ALLOW LIGHT RAIN TO HANG ON A LITTLE LONGER ACROSS NC. THE CANADIAN HAS BEEN CONSISTENTLY SHOWING A DRY FORECAST AS HAS THE ECMWF WITH BOTH KEEPING THE LOW A LITTLE FARTHER OFFSHORE. WENT WITH A BLEND OF THESE IDEAS...SCALED BACK POPS INLAND BUT DID GO WITH AN INCREASE FOR SOUTHEASTERN BRUNSWICK AND COASTAL NEW HANOVER/PENDER. STILL KEEPING POPS IN THE CHANCE RANGE HERE...BUT ON THE HIGH END OF THE SCALE. ALSO INCREASED POPS FOR COASTAL SC...BUT DID NOT GO QUITE AS HIGH AS IN NC COUNTIES. IN ADDITION TO A DIFFICULT POP FORECAST CLOUDS AND TEMPS WILL BE TRICKY WITH A SHARP GRADIENT BETWEEN FULL CLOUD AND FULL SUN. FARTHER FROM THE COAST TEMPS ON WED COULD RUN 5-10 DEGREES WARMER THAT WHAT IS CURRENTLY FORECAST SHOULD SKIES CLEAR. COAST WILL REMAIN UNDER CLOUD COVER...EVEN IF PRECIP DOES NOT MATERIALIZE. CLOUDS THIN THU MORNING AND HEIGHT FALL A LITTLE...LOWS WILL STILL END UP ABOVE CLIMO...BUT ONLY BY A FEW DEGREES. SUNSHINE AND SOUTHWEST FLOW ON THANKSGIVING RESULT IN A DRY AND SEASONABLE DAY. STRONG COLD FRONT MOVES ACROSS THE AREA LATER THU NIGHT WITH SURFACE HIGH AND UPPER TROF MOVING IN. STRONG COLD ADVECTION BEGINS AFTER MIDNIGHT WITH 850 TEMPS DROPPING SEVERAL DEGREES BETWEEN 06Z AND 12Z. STRONG NORTHWEST FLOW WILL KEEP BOUNDARY LAYER MIXED...BUT COLD AIR FUNNELING IN WILL RESULT IN LOWS NEAR TO A LITTLE BELOW CLIMO. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 3 PM TUESDAY...VERY LITTLE HAS CHANGED WITH REGARDS TO THE EXTENDED AS THE BEGINNING OF THE PERIOD SHOULD BE CHARACTERIZED BY COLD AND DRY CONDITIONS WITH THE LATTER PERIODS BECOMING DOMINATED BY A STRONG STORM SYSTEM. NUMERICAL GUIDANCE CONTINUES TO ADVERTISE WIDESPREAD 30S SATURDAY AND SUNDAY MORNINGS AS ARCTIC HIGH PRESSURE SETTLES ACROSS THE SOUTHEAST. DEEP PHASING AT THE MID LEVELS ACROSS THE CENTRAL U.S. ALLOWS A DEEP SURFACE CYCLONE TO DEVELOP AND MOVE ACROSS THE SOUTHEAST LATER MONDAY AND TUESDAY. INCREASED POPS A BIT HERE BASED ON MODEL CONSISTENCY. && .AVIATION /20Z TUESDAY THROUGH SUNDAY/... HIGH PRESSURE CONTINUES TO WEDGE INTO THE COASTAL PLAIN AND LOW PRESSURE WILL EMERGE FROM THE GULF OF MEXICO AND CROSS OVER FLORIDA...AND EVENTUALLY RIDE UP THE ATLANTIC SEABOARD AFTER THIS TAF PERIOD. THIS WILL KEEP CEILINGS IFR FOR SEVERAL MORE HOURS. LOOK FOR SLIGHT IMPROVEMENT IN CEILINGS DURING LATE AFTERNOON AND EVENING TO MVFR. VISIBILITY VFR TO START THE PERIOD AND BACK TO MVFR OVERNIGHT. WIND TO BECOME LIGHT AND VARIABLE AS THE HIGH PRESSURE WEDGE SETTLES INTO THE AREA...AFTER 14Z WIND DIRECTION SETTLES INTO NORTHEASTERLY BUT STILL LIGHT AS LOW ORGANIZES TO OUR SOUTH. EXTENDED OUTLOOK...IMPROVING TO MVFR/VFR CONDITIONS FOR WEDNESDAY...POSSIBLE IFR FOR THURSDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM TUESDAY...FAIRLY BENIGN CONDITIONS WITH LATEST BUOY OBS SHOWING N-NW WINDS JUST UNDER 10 KT. SEAS RUNNING 2-3 FT...WITH A LIGHT WIND CHOP ON TOP OF A 8-9SEC ESE SWELL. IF ANYTHING WE COULD SEE A SLIGHT VEERING TO NE TONIGHT AS LOW PRESSURE TAKES SHAPE OVER FLORIDA...BUT OTHERWISE STATUS QUO AS THE GRADIENT REMAINS QUITE WEAK. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 PM TUESDAY...LIGHT VARIABLE FLOW ON WED WILL BECOME NORTHERLY WITH A MARGINAL INCREASE IN WIND SPEEDS AS SURFACE LOW MOVES UP THE EAST COAST. SPEEDS WILL EVENTUALLY TOP OUT AROUND 15 KT LATE WED INTO THU AS LOW PASSES EAST OF WATERS AND BECOMES MORE DEVELOPED. FLOW TURNS OFFSHORE AS LOW EXITS OFF TO THE NORTHEAST ON THU. NOT MUCH OF A BUILD UP IN SEAS WED NIGHT INTO THU DESPITE SLIGHT INCREASE IN SPEEDS...DURATION OF STRONGER WINDS IS TOO SHORT AND THEN THE FLOW BECOMES OFFSHORE. SHOULD NOT NEED HEADLINES INTO THU...BUT MAY NEED HEADLINES LATE THU NIGHT IF STRONG COLD ADVECTION DEVELOPS AS EXPECTED. LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 3 PM TUESDAY...STRONG WEST TO NORTHWEST WINDS WILL PREVAIL FRIDAY INTO EARLY SATURDAY ACROSS THE WATERS AS ARCTIC HIGH PRESSURE BUILDS INTO THE AREA. WINDS WILL PROBABLY STAY BELOW FLAG CRITERIA HOWEVER. GRADIENT RELAXES CONSIDERABLY LATE SATURDAY INTO SUNDAY AS THE HIGH MOVES ACROSS. SEAS WILL FOLLOW THE SAME TREND...HIGHEST EARLY ALTHOUGH ONCE AGAIN...PROBABLY BELOW FLAG CRITERIA...DIMINISHING LATE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...RAS SHORT TERM...III LONG TERM...SHK AVIATION...MDC