000 FXUS61 KBOX 221052 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 552 AM EST SUN NOV 22 2009 .SYNOPSIS... HIGH PRESSURE EXTENDING FROM NEW YORK STATE INTO QUEBEC WILL MOVE ACROSS NORTHERN NEW ENGLAND INTO THE MARITIMES TONIGHT...THEN EAST OF NOVA SCOTIA MONDAY. LOW PRESSURE WILL BRING RAIN TO THE REGION LATE MONDAY INTO TUESDAY. WEAK HIGH PRESSURE WILL TEMPORARILY BUILD INTO THE REGION TUESDAY NIGHT INTO WEDNESDAY NIGHT THEN MOVE OFFSHORE THANKSGIVING DAY. ANOTHER LOW PRESSURE SYSTEM WILL MOVE UP THE COAST LATE THURSDAY AND FRIDAY BRINGING A CHANCE OF MORE RAIN. COLDER BLUSTERY WEATHER IS FORECAST FOR SATURDAY BEHIND THAT DEPARTING LOW. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SKIES WERE GENERALLY CLEAR ACROSS THE REGION EARLY THIS MORNING... EXCEPT FOR LOCALIZED LOW CLOUDS AND FOG ACROSS A FEW OF THE NORMALLY SUSCEPTIBLE VALLEY AREAS. CAN ALSO SEE LOW CLOUDS EXTENDING FROM S VT INTO THE BERKSHIRES AND ALL ACROSS NY STATE/PA ON THE SATELLITE FOG PRODUCT. ONCE THE SUN RISES...NOT EXPECTING THESE CLOUDS TO STICK AROUND TOO LONG...EVEN WITH LOW SUN ANGLE. HIGH PRES ACROSS NY STATE INTO EASTERN CANADA WILL SLOWLY MOVE NE TODAY. THIS WILL INSURE MOSTLY CLEAR SKIES FOR MOST AREAS. SOME OF THE MODELS...ESPECIALLY THE CANADIAN REGIONAL GEM...HAS BEEN HINTING AT LOW CLOUDS DEVELOPING OFFSHORE AND MOVING IN ALONG THE COAST. THE RGEM TENDS TO HANDLE CLOUDS WELL. ALSO NOTED HIGH RH VALUES AND LOW CLOUDS ON THE NAM BUFKIT CROSS SECTIONS FOR THIS AFTERNOON ALONG THE COAST. HAVE ADDED ONLY PARTLY CLOUDY SKIES ACROSS SE MA...CAPE COD AND THE ISLANDS FOR NOW. AS LIGHT WINDS VEER AROUND TO N-NE...WILL SEE DAYTIME HIGHS ON THE COOLER SIDE TODAY ESPECIALLY ALONG THE COAST. FORECASTING HIGHS MAINLY IN THE LOWER-MID 50S...WHICH CONTINUED TO RUN UP TO 5 DEGREES OR SO ABOVE NORMAL. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... TONIGHT...HIGH PRESSURE WILL CONTINUE TO SHIFT NE ACROSS NOVA SCOTIA. THIS...ALONG WITH LOW PRES DEVELOPING OFF THE MID ATLC COAST WILL CAUSE A TIGHTENING PRES GRADIENT...SLOWLY INCREASING THE E-NE WIND ESPECIALLY ALONG THE COAST. RGEM CONTINUES TO PUSH LOW CLOUDS AND FOG INTO COASTAL AREAS...AND EVEN FURTHER INLAND. HOWEVER...WITH THE DEVELOPING LOW PRES OFF THE MID ATLC...WILL ALSO START TO SEE MOISTURE WORK UP THE COAST AS WELL. HAVE FORECASTED INCREASING CLOUDS THROUGH THE NIGHT ACROSS CENTRAL AND SOUTHERN AREAS. OVERNIGHT LOWS WILL FALL BACK TO THE 30S TO AROUND 40...THOUGH MOS GUIDANCE MAY BE A BIT TOO COLD CONSIDERING THE INCREASING CLOUDS AND ONSHORE WIND...MAINLY S OF THE MASS PIKE. MONDAY...CONDITIONS WILL DETERIORATE DURING THE DAY AS THE LOW STARTS TO SLOWLY WORK NE. MODELS TRY TO BRING PRECIP INTO THE REGION DURING THE DAY...WITH THE CANADIAN GEM MODELS BEING THE MOST AGGRESSIVE. WITH THE STRONG HIGH TO THE N...FEEL THE DRY AIRMASS OVER THE REGION WILL HOLD THE PRECIP OFF THROUGH AT LEAST MIDDAY... AND PROBABLY NOT UNTIL NIGHTFALL OR AFTER ACROSS N MA/S NH. HAVE BROUGHT CHANCE POPS INTO SOUTHERN AREAS DURING THE AFTERNOON AS THE AIRMASS MOISTENS UP WITH THE ONSHORE FLOW AS WELL AS THE PRECIP WORKING UP THE COAST. WITH THE ONSHORE FLOW CONTINUING TO INCREASE AND THE APPROACHING PRECIP...EXPECT DAYTIME HIGHS ONLY IN THE UPPER 40S TO MID 50S... BUT THIS WILL STILL BE UP TO 5 DEGREES ABOVE SEASONAL NORMS. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... MONDAY NIGHT AND TUESDAY... MODELS NOW ALL IN LINE WITH LOW PRESSURE MOVING FROM SOUTH OF NANTUCKET MONDAY EVENING TO NEAR NOVA SCOTIA LATE TUESDAY NIGHT. RAIN WILL MOVE ACROSS THE REGION FROM SOUTH TO NORTH MONDAY EVENING. RGEM IS FASTEST OF 00Z MODELS RUNS WITH PRECIP IN RI AND CT BEFORE 7 PM MON. 00Z GFS WAS CONSIDERED OUTLIER WITH THE LOW TOO FAR OFF THE COAST AND LITTLE RAINFALL OVER LAND. ECMWF TIMING AND PRECIP WAS THE BASIS FOR THIS FORECAST. NEW 06Z GFS RUN NOW IS MORE IN LINE...EVEN THOUGH ITS LOW IS STILL FARTHER EAST THAN THE OTHER MODELS...IT NOW HAS RAIN AS FAR NORTH AS THE CT/RI/MA BORDER BY MON EVENING. HAVE INCREASED POPS TO 60 PERCENT NORTHWEST AND 90 PERCENT SOUTHEAST. IN GENERAL...0.5 INCHES OF RAIN IS EXPECTED IN MANY AREAS. HOWEVER... THE COMBINATION OF STRONG MOIST ESE FLOW AT 925 MB OVERRUNNING LESSER NE FLOW AT THE SURFACE WILL LEAD TO THE POTENTIAL FOR LOCALLY HEAVY SHOWERS BETWEEN MIDNIGHT AND NOON TUESDAY. BEST CHANCE IS ALONG EASTERN MA COAST. GFS SHOWS MORE THAN 2 INCHES OF RAIN OVER THE OPEN WATERS...THIS WILL NEED TO BE WATCHED IN CASE HEAVY RAIN OCCURS OVER THE COASTAL AREAS. DESPITE PERSISTENT ONSHORE FLOW MONDAY/TUESDAY...ASTRONOMICAL TIDES ARE LOW AND THE SYSTEM DOES NOT APPEAR INTENSE ENOUGH TO RESULT IN ANY COASTAL FLOODING. HOWEVER...MINOR BEACH EROSION CERTAINLY IS POSSIBLE. STUCK WITH PREVIOUS FORECAST HIGH TEMPERATURES SINCE THEY WERE SIGNIFICANTLY COOLER THAN GFS GUIDANCE. CONFIDENCE IS HIGH THAT IT WILL BE COOL AND RAW DURING THE AFTERNOON WITH THE ONSHORE FLOW. TUESDAY NIGHT AND WEDNESDAY... LOW PULLS OUT TO THE EAST AND WEAK HIGH PRESSURE MOVES IN. THE PROBLEM IS THAT THERE WILL STILL BE ABUNDANT LOW LEVEL MOISTURE. 925 MB RELATIVE HUMIDITY REACHES 90-100 PERCENT WED AFTERNOON. HAVE GONE WITH CLOUDY FORECAST. REDUCED CHANCE OF SHOWERS TO 20 TO 30 PERCENT IN NW HALF OF AREA BECAUSE GFS SHOWED A WEAK VORTICITY MAX MOVING THROUGH IN THE FAST SW FLOW ALOFT. SHOULD BE LIGHT IF ANYTHING DUE TO DRYING AIR ALOFT. HIGHS SHOULD MAINLY BE FROM 50 TO 55. WEDNESDAY NIGHT THROUGH THANKSGIVING... MORE OF THE SAME... GENERALLY MOSTLY CLOUDY SKIES DUE TO LOW LEVEL MOISTURE AS FLOW REMAINS EASTERLY BEHIND DEPARTING WEAK HIGH PRESSURE AND AHEAD OF DEVELOPING LOW PRESSURE OFF THE CAROLINA COAST. HAVE LOW PROBABILITIES OF SHOWERS... BUT IT MAY TURN OUT TO BE MORE OF A CHANCE OF DRIZZLE ACROSS THE AREA. LOWS MID 30S TO LOWER 40S AND HIGHS IN THE 50S. THURSDAY NIGHT THROUGH FRIDAY NIGHT... A VIGOROUS UPPER LEVEL TROUGH DEVELOPING FROM THE GREAT LAKES TO THE OHIO VALLEY WILL INTENSIFY THE CAROLINA LOW PRESSURE SYSTEM AS IT MOVES NORTHWARD UP THE EAST COAST. 00Z GFS DEEPENS IT TO 973 MB OVER NEW ENGLAND COMPLETE WITH LOTS OF THUNDER ETC. 06Z GFS CONTINUES THIS FORECAST WITH 974 MB. THESE WERE CONSIDERED TOO DEEP AS ECMWF REMAINS CONSISTENT WITH 998 MB WHICH IS WEAKER THAN ITS PREVIOUS RUN OF 993 MB. THE PLACEMENT OF THIS STORM WILL DETERMINE WHERE THE HEAVIEST RAIN WOULD FALL. RIGHT NOW...WE HAVE ADDED 50 TO 60 PERCENT POPS TO THE FORECAST FROM LATE THU NIGHT THROUGH FRIDAY...DIMINISHING SOMEWHAT FRI NIGHT. IT SHOULD BE NOTED THAT THE CANADIAN GGEM MODEL IS DRY THROUGHOUT FRIDAY. THUS AT THIS TIME...CONFIDENCE IS ONLY MEDIUM THAT A STORM WILL FORM...AND EVEN LOWER AS TO ITS PLACEMENT. SATURDAY... BLUSTERY AND CHILLY WEATHER LOOKS TO BE FILTERED INTO THE REGION BEHIND THE SYSTEM. WITH THE UPPER LOW PRESSURE DIRECTLY OVERHEAD...EXPECT RATHER UNSTABLE CONDITIONS WHICH COULD LEAD TO A FEW RAIN SHOWERS IN THE SOUTH AND EAST AND SNOW SHOWERS IN THE NORTHWEST...ESPECIALLY IN THE HIGHER TERRAIN. IT WILL BE TOO WARM AT THE SURFACE FOR ANY ACCUMULATION. HIGHS ARE FORECAST TO BE IN THE UPPER 30S NORTHWEST TO MID 40 SOUTHEAST. && .AVIATION /10Z SUNDAY THROUGH THURSDAY/... TODAY...VFR. MAY SEE PATCHY VFR TO LOCAL MVFR CIGS ALONG THE COAST DURING THE LATE MORNING AND AFTERNOON. TONIGHT...VFR MOST LOCATIONS. WILL LIKELY SEE MVFR CIGS MOVING IN ALONG THE COAST S AND E OF A LINE FROM KBOS-KPVD...MAINLY NEAR OR AFTER MIDNIGHT. WILL ALSO SEE E-NE WINDS INCREASE ACROSS CAPE COD AND THE ISLANDS. MONDAY...EXPECT VFR CIGS MAINLY N OF ROUTE 2 ACROSS N MA...WHILE CONDITIONS LOWER TO MVFR-IFR CIGS S OF THERE. LOCAL IFR CIGS ALONG THE S COAST...CAPE COD AND THE ISLANDS DURING THE AFTERNOON. PATCHY RAIN WILL APPROACH N CT/RI/SE MA DURING THE AFTERNOON WITH LOCAL MVFR VSBYS. OUTLOOK /MONDAY NIGHT THROUGH FRIDAY/... MONDAY NIGHT AND TUESDAY...IFR CONDITIONS IN LOW CLOUDS... RAIN AND FOG. LOCALLY HEAVIER SHOWERS MAINLY EASTERN SECTIONS. TUE NIGHT THROUGH THU...MVFR-IFR CONDITIONS MAY LINGER IN LOW CLOUDS THROUGH THIS PERIOD. ONLY SLIGHT CHANCE OF A RAIN SHOWER BUT MAY HAVE AREAS OF DRIZZLE AND FOG DEVELOPING...ESPECIALLY WED NIGHT. THU NIGHT AND FRI... LOW TO MEDIUM CONFIDENCE OF IFR CEILINGS AND VSBYS IN SHOWERS. && .MARINE... TODAY...NE WINDS WILL GRADUALLY INCREASE DURING THE DAY. WITH THE INCREASING WIND AND ONSHORE FETCH...EXPECT SEAS TO BUILD UP TO 5 FT MAINLY ON THE EASTERN OUTER WATERS. HAVE CONTINUED SMALL CRAFT ADVISORY. TONIGHT...AS LOW PRES WORKS UP THE COAST...WILL SEE E-NE WINDS CONTINUE TO INCREASE. EXPECT WIND GUSTS UP TO 25 KT...MAINLY ON THE SOUTHERN WATERS. SEAS WILL CONTINUE TO BUILD ON MOST OF THE WATERS...SO HAVE PUT UP SMALL CRAFTS LATE TONIGHT FOR THE S SOUNDS. MONDAY...E-NE WIND GUSTS UP TO 30 KT ON THE OUTER WATERS. SEAS CONTINUE TO BUILD...POSSIBLY UP TO 8 FT WELL OFFSHORE. OUTLOOK /MONDAY NIGHT THROUGH THURSDAY/... MONDAY NIGHT THROUGH EARLY WEDNESDAY...LOW PRESSURE PASSING FROM SOUTH OF NANTUCKET TO NOVA SCOTIA WILL CREATE A PERSISTENT NORTHEAST FLOW AND GOOD GRADIENT. THIS WILL RESULT IN SCA ACROSS MOST OF OUR WATERS OVER THIS TIME PERIOD. SEAS MAY BUILD TO BETWEEN 7 AND 12 FEET ACROSS THE OUTER WATERS. THERE IS A LOW PROBABILITY OF BRIEF MARGINAL GALE FORCE GUSTS MAINLY VERY LATE MON NIGHT OR ON TUESDAY OVER THE SOUTHERN WATERS. WEDNESDAY THROUGH THANKSGIVING...WINDS WILL CONTINUE FROM A PERSISTENT EASTERLY DIRECTION PERHAPS BECOMING SOUTHEAST LATER THU. THIS WILL LIKELY CAUSE SEAS TO REMAIN ABOVE SCA THRESHOLDS ACROSS THE OUTER-WATERS. WINDS AND SEAS MAY ONCE AGAIN INCREASE VERY LATE THANKSGIVING NIGHT IN ADVANCE OF THE NEXT SYSTEM APPROACHING FROM THE SOUTH. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM 5 AM TO 5 PM EST MONDAY FOR ANZ232>235-237. SMALL CRAFT ADVISORY FROM NOON TODAY TO 5 PM EST MONDAY FOR ANZ250-254>256. && $$ SYNOPSIS...EVT/GAF NEAR TERM...EVT SHORT TERM...EVT LONG TERM...GAF AVIATION...EVT/GAF MARINE...EVT/GAF