FXUS61 KBOX 202050 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 350 PM EST TUE JAN 20 2009 .SYNOPSIS... DEVELOPING LOW PRESSURE OFF THE CAROLINA COAST WILL PASS WELL SOUTHEAST OF NANTUCKET TONIGHT. HIGH PRESSURE OVER THE SE USA WED STARTS A SMALL WARMING TREND HERE THU. LOW PRESSURE WILL LIKELY PASS ACROSS NORTHERN NEW ENGLAND FRIDAY ALONG A SAGGING ARCTIC FRONT BOUNDARY BEFORE COLDER HIGH PRESSURE BUILDS IN FOR NEXT WEEKEND. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... OCEAN EFFECT SNOWS WELL UNDERWAY OVER MASS BAY AT 330 PM AND MOVING ONSHORE TO PLYMOUTH COUNTY. LATEST RADAR/SATELLITE AND MODEL TRENDS ARE FOR SNOW SHOWERS TO BE CONFINED TO PLYMOUTH COUNTY/CAPE COD AND NANTUCKET TONIGHT...AS BOUNDARY LAYER FLOW REMAINS NNE. BOUNDARY LAYER AND SST DELTA-T NEVER EXCEEDS 15C. THIS WILL LIMIT MOISTURE AND HEAT FLUXES AND SHOULD KEEP SNOW ACCUMULATIONS TO AN INCH OR LESS. ALL OF THIS COURTESY OF A DEVELOPING GALE OFF THE CAROLINA COAST INDUCING COLD MOIST NNE FLOW ACROSS EASTERN MA. HOWEVER GIVEN THE TIMING OF THE LATE DAY COMMUTE...COULD HAVE SOME SLIPPERY TRAVEL ALONG RT-3 IN PLYMOUTH COUNTY AND INTO CAPE COD THIS EVENING. LATEST WEB CAM FROM PROVINCETOWN INDICATES A COATING ON THE GROUND THERE. WILL ISSUE A SPECIAL WEATHER STATEMENT TO INCREASE AWARENESS OF SOME SLIPPERY TRAVEL IN PLYMOUTH COUNTY /ESPECIALLY RT-3/ AND CAPE COD THIS EVENING. BOUNDARY LAYER WINDS BEGIN TO BACK TO THE NNW TOWARD DAYBREAK. THIS SHOULD SHIFT SNOW BANDS EASTWARD AND BEGIN TO MOVE OFFSHORE. IN ADDITION...IT WILL BE BLUSTERY ACROSS EASTERN MA ESPECIALLY CAPE COD AND THE ISLANDS. OTHERWISE...EXPECT QUIET WEATHER TONIGHT ACROSS THE REMAINDER OF THE REGION. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... AS MENTIONED ABOVE LOW LEVEL WINDS BACK TO THE NORTHWEST AS OCEAN GALE MOVES SEAWARD. THIS WILL BRING AN END TO THE OCEAN EFFECT SNOW SHOWERS ACROSS CAPE COD AND NANTUCKET. MUCH COLDER WED AS COLD AIR ADVECTION DEVELOPS ACROSS NEW ENGLAND ON THE BACKSIDE OF DEPARTING OCEAN LOW. ONLY FLY IN THE OINTMENT WED AFTN AND EVENING IS AN APPROACHING SHORT WAVE TROF MOVING ACROSS NY STATE. MODEST LIFT ASSOCIATED WITH THIS FEATURE...HOWEVER MOISTURE AND INSTABILITY IS LACKING. THEREFORE COVERAGE OF ANY SNOW SHOWER OR FLURRY ACTIVITY SHOULD BE LIMITED. && .LONG TERM /THURSDAY THROUGH TUESDAY/... LOOKS TO BE MOSTLY DRY THROUGH THIS PERIOD WITH ANOTHER SURGE OF ARCTIC AIR THIS WEEKEND. ANTICIPATING NEAR NORMAL TEMPS THU AND FRI. EXPECT QUITE A LOT OF SUN ON THU BUT THEN INCREASING CLOUDINESS OVER THE NORTHERN HALF OF FORECAST AREA ON FRI DUE TO OVERRUNNING AHEAD OF SURFACE LOW PRES HEADING E ALONG THE ARCTIC FRONT FROM THE GREAT LAKES. ALL MEDIUM RANGE MODELS ADVERTISE THIS CLIPPER SYSTEM MOVING ALONG THE ARCTIC FRONT ON FRI AND FRI NIGHT...MOVING IT ACROSS NORTHERN NEW ENGLAND...WHICH WOULD RESULT IN LITTLE OR NO MEASURABLE PCPN FOR SNE. A FEW GFS ENSEMBLE MEMBERS DID SHOW A MORE SOUTHERLY TRACK AND WITH THE ARCTIC FRONT SLIDING S TO AT LEAST CENTRAL NEW ENGLAND ON FRI...WE ARE A LITTLE WARY THAT SURFACE LOW PRES MIGHT END UP A LITTLE FURTHER SOUTH. THIS LOOKS TO BE A RATHER ROBUST DOME OF ARCTIC AIR AND HAS PLENTY OF SNOW COVER UNDERNEATH TO INHIBIT MODERATION. THUS...HAVE PUT LOW CHANCE POPS ACROSS THE SW NH ZONES AND SLGT CHANCE ELSW FOR FRI NIGHT. AS CLIPPER SURFACE LOW HEADS TOWARD THE CANADIAN MARITIMES AND DEEPENS...THE DOOR OPENS FOR ANOTHER SURGE OF VERY COLD ARCTIC AIR. BELIEVE MEX GUIDANCE...INFLUENCED BY CLIMO...MAY NOT BE COLD ENOUGH AND DROPPED TEMPS SOME FOR SAT. SHOULD BEGIN TO MODERATE ON SUN. ARCTIC FRONTAL BOUNDARY LOOKS TO REMAIN ACROSS OR NEAR SNE COAST FOR START OF NEXT WEEK. THAT LEAVES OUR AREA OPEN TO ANY WAVES ALONG IT. FOR NOW HAVE STAYED DRY...NO CHANCE POPS...THROUGH MON. ALTHOUGH A LONG WAYS AWAY...ALL MEDIUM RANGE MODELS POINT TOWARD A POTENTIAL MAJOR WINTER STORM NEXT WEEK AS SHORT WAVE ENERGY EXITS THE SW PLAINS...DRAWS IN GULF MOISTURE...AND THEN LIKELY REDEVELOPS ALONG MID ATLC COAST JUST S OF ARCTIC AIR DOME. TIMING IS UNCERTAIN WITH GFS SEEMINGLY THE FASTEST RIGHT NOW. && .AVIATION /21Z TUESDAY THROUGH SUNDAY/... TONIGHT...VFR EXCEPT MVFR CONDS IN SNOW SHOWERS HYA ACK AND FMH. A LOW PROBABILITY OF IFR CONDITIONS FOR A TIME AT THESE 3 TERMINAL. SNOW ACCUMULATIONS OF AN INCH OR LESS EXPECTED. WED...VFR. ONLY EXCEPTION TO THIS COULD BE ON THE CAPE AND ISLANDS WHERE SNOW SHOWERS COULD LINGER THROUGH THE MORNING HOURS REDUCING CONDITIONS TO MVFR/IFR. WED...VFR. LOW PROB OF MVFR BDL/BAF IN ISOLATED LATE DAY/EVENING SNOW SHOWER. OUTLOOK /WEDNESDAY NIGHT THROUGH SATURDAY/... VFR CONDITIONS EXPECTED THROUGH SAT...ALTHOUGH THERE IS A SLIGHT CHANCE OF SNOW SHOWERS THAT LOWER CIGS AND VSBYS TO MVFR FRI NIGHT ACROSS SW NH. NW WINDS SAT MAY PRODUCE LOW LEVEL MECHANCIAL TURBULENCE. && .MARINE... TONIGHT... N WINDS GUSTING TO 25 KT ACROSS THE EASTERN MA WATERS. SNOW SHOWERS WILL LIMIT VSBY TO AROUND 1 MILE AT TIMES. WED... N WINDS BECOME NW AND DIMINISH IN SPEED. HOWEVER SEAS WILL LIKELY BE 5 FT OR HIGHER ACROSS THE OCEAN WATERS. VSBY MAY LOWER TO 1 MILE IN MORNING SNOW SHOWERS ACROSS EASTERN MA WATERS...BUT IMPROVING DURING THE AFTERNOON. FREEZING SPRAY POSSIBLE. WED NIGHT... WNW WINDS CONTINUE WITH GOOD VSBY. FREEZING SPRAY POSSIBLE. OUTLOOK /THURSDAY THROUGH SATURDAY/... WINDS AND SEAS INCREASE BEHIND CLIPPER LOW AS IT HEADS ACROSS NORTHERN NEW ENGLAND FRI NIGHT AND TO THE CANADIAN MARITIMES ON SAT. MAY SEE NW GALE ON AT LEAST SOME OF THE WATERS SAT AS WELL AS A RETURN TO WIDESPREAD AND SIGNIFICANT FREEZING SPRAY. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST WEDNESDAY FOR ANZ231-232- 250-254-255. && $$ SYNOPSIS...NOCERA - UPDATED 347 PM NEAR TERM...NOCERA - UPDATED 347 PM SHORT TERM...NOCERA - UPDATED 347 PM LONG TERM...THOMPSON AVIATION...NOCERA/THOMPSON - UPDATED 347 PM MARINE...NOCERA/THOMPSON - UPDATED 347 PM