Area Forecast Discussion
Issued by NWS Portland, ME

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669 FXUS61 KGYX 081519 AAC AFDGYX AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GRAY ME 1019 AM EST MON FEB 8 2016 .SYNOPSIS... INTENSIFYING LOW PRESSURE OFF THE CAROLINA COAST WILL MOVE NORTHEAST AND PASS WELL TO THE EAST OF CAPE COD LATE TODAY. ANOTHER LOW WILL FORM OFF THE MID ATLANTIC COAST AND MOVE TOWARD CAPE COD ON TUESDAY. THE RESULT WILL BE WIDESPREAD SNOWFALL ACROSS THE REGION. A TROUGH OF LOW PRESSURE WILL SLOWLY MOVE OUT OF THE AREA WEDNESDAY AND THURSDAY. MUCH COLDER AIR WILL MOVE SOUTH OUT OF CANADA AND INTO NEW ENGLAND FOR THE UPCOMING WEEKEND. && .NEAR TERM /UNTIL 5 PM THIS AFTERNOON/...
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1010 AM...PRECIPITATION SHIELD CONTINUES TO EVAPORATE ON THE NORTHERN PERIPHERY. WHILE BOSTON IS RECEIVING WIND DAMAGE AND NEAR BLIZZARD CONDITIONS ARE OCCURING ON THE CAPE...SO FAR NO SNOW HAS REACHED THE GROUND IN NH OR MAINE DUE TO THE VERY DRY AIRMASS IN PLACE. NORTH WINDS CONTINUE TO DRAW DRIER AIR SOUTH AND IN FACT DEW POINTS ARE DROPPING IN MUCH OF THE REGION. NEAR ZERO OR NEGATIVE DEW POINTS WILL KEEP SNOW ALOFT EVAPORATING INTO VIRGA FOR SEVERAL MORE HOURS. WE SHOULD SEE SNOW BEGIN TO REACH THE GROUND IN SW NH AND PERHAPS PORTIONS OF COASTAL MAINE WITHIN 2-4 HOURS BEFORE SPREADING INLAND. AGAIN THE MAIN ISSUE PRECLUDING THIS IS A VERY DRY LOW LEVEL AIRMASS AS NOTED ON THE KGYX 12Z SOUNDINGS...IN FACT IT IS DRY UP TO 500MB OR ABOUT 17K FT. WINDS HAVE BEGUN TO COME UP HOWEVER WITH GUSTS INTO THE MID TO UPPER 20S SO FAR. WE WILL SEE GUSTS INTO THE LOWER TO MID 30S BY THIS AFTERNOON. ADJUSTED SKY COVER...QPF TIMING...TEMPERATURES...AND DEW POINTS WHICH HAVE BEEN VERY UNDERFORECAST BY THE MODELS. 635 AM...MINOR ESTF UPDATE TO NEAR TERM GRIDS TO REFLECT CURRENT RADAR AND SATELLITE TRENDS...AND TO INGEST THE 11Z MESONET. I SLOWED DOWN THE NORTHWARD PROGRESSION OF PRECIPITATION INTO THE FORECAST AREA BY SEVERAL HOURS THIS AM. PREV DISC... NO CHANGE TO CURRENT WINTER WEATHER HEADLINES. AT 07Z...THE ARCTIC COLD FRONT HAD DROPPED SOUTH OF OUR AREA. AN INTENSIFYING 980 MILLIBAR LOW WAS CENTERED OFF THE NORTH CAROLINA COAST. FOR TODAY...CLOUD SHIELD FROM THE OCEAN STORM WILL SPREAD NORTHWARD ACROSS THE FORECAST AREA THIS MORNING. NWS RADAR MOSAIC SHOWED LEADING BANDS OF PRECIPITATION APPROACHING SOUTHEAST NEW ENGLAND COAST. THESE BANDS WILL CONTINUE TO SPREAD NORTH AND WEST TODAY. SOME CONCERN ON SNOW AMOUNTS...ESPECIALLY OVER NORTHERN AREAS...AS THE DRY ARCTIC AIR CONTINUES TO SPILL SOUTHWARD INTO THE FORECAST AREA AND WITH OCEAN LOW TRACKING WELL SOUTH AND EAST OF THE 40N/70W BENCHMARK. THERE WILL LIKELY BE A TIGHT GRADIENT IN SNOWFALL AMOUNTS WITH THIS SYSTEM...AND WE MAY NEED TO ADJUST TOTALS DOWN A BIT OVER THE CONNECTICUT VALLEY AS WELL AS THE INTERNATIONAL BORDER AREAS IN LATER UPDATES. NORTHEAST WINDS WILL INCREASE TODAY AS PRESSURE GRADIENT TIGHTENS BETWEEN THE OCEAN LOW AND 1033 MILLIBAR HIGH OVER QUEBEC PROVINCE. HIGHS TODAY WILL RANGE FROM THE TEENS IN THE NORTHERN MOUNTAINS TO THE 20S ELSEWHERE. THE DEVELOPING SNOW AND GUSTY WINDS WILL MAKE FOR AN INTERESTING AFTERNOON COMMUTE ACROSS THE REGION.
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&& .SHORT TERM /5 PM THIS AFTERNOON THROUGH TUESDAY NIGHT/... SNOW WILL TAPER TO SNOW SHOWERS TONIGHT WITH DIMINISHING SURFACE WINDS FOLLOWING PASSAGE OF SHORTWAVE IMPULSE AND AS THE OCEAN LOW RACES INTO THE MARITIMES. LOWS WILL RANGE FROM SINGLE NUMBERS NEAR THE INTERNATIONAL BORDER WITH TEENS ELSEWHERE. THE NEXT SHORTWAVE IMPULSE ROUNDS THE BASE OF THE TROUGH AND GIVES RISE TO A SECOND INTENSIFYING OCEAN LOW THAT WILL ONCE AGAIN PASS WELL SOUTH AND EAST OF THE 40N/70W BENCHMARK. QPF WILL BE LESS THAN TODAY WITH SNOW SHOWER ACTIVITY PRODUCING ONLY LIMITED ACCUMULATIONS ACROSS THE FORECAST AREA. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... EXTENDED BEGINS WITH DEEP TROF ACROSS THE ERN CONUS...SLOWLY LIFTING NEWD THRU THE REMAINDER OF THE WEEK. PASSAGE OF THE UPPER TROF WILL LIKELY BRING WIDESPREAD SN SHOWERS TO THE AREA INTO WED. SMALLER S/WV TROFS WITHIN THE FLOW MAY ENHANCE OR FOCUS SN SHOWERS INTO A SMALLER AREA...BUT DETAILS ON WHEN AND WHERE WILL BE WORKED OUT ONCE TODAY/S POWERFUL OCEAN STORM CLEARS THE STAGE. GEFS AND ECMWF EPS ARE IN AGREEMENT THRU THE REST OF THE FORECAST...THAT RIDGING BUILDS ACROSS THE WRN CONUS...AND THIS HELPS TO CARVE THE TROF OVER THE E AGAIN. THIS PATTERN WILL BE FAVORABLE FOR TEMPS AVERAGING OUT BELOW NORMAL. IN FACT THERE IS A FAIRLY STRONG MODEL SIGNAL FOR A SIGNIFICANT PIECE OF THE POLAR CIRCULATION TO ROTATE DOWN ACROSS SRN CANADA LATE IN THE WEEK. AS CURRENTLY MODELED THIS WOULD LIKELY BE THE COLDEST AIR OF THE SEASON SO FAR. THAT TIME PERIOD WILL ALSO BEAR WATCHING FOR A S/WV SPILLING OVER THE RIDGE AND UNDER THE POLAR LOW. THE 08.00Z ECMWF EPS HAS A GOOD SIGNAL FOR LATE BLOOMING LOW PRES DEVELOPMENT IN THE GULF OF ME EARLY IN THE WEEKEND. THE GEFS AND GFS ALSO DEVELOP THIS SAME WAVE...HOWEVER IT IS MUCH MORE PROGRESSIVE AND FARTHER SE. GIVEN THAT BOTH MODELS HAVE SOMETHING THERE...IT IS SOMETHING TO KEEP AN EYE ON. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... SHORT TERM...VFR CONDITIONS WILL GIVE WAY TO GRADUALLY LOWERING CEILINGS AND LIGHT SNOW BY EARLY AFTERNOON. OCCASIONAL IFR CONDITIONS WILL BE POSSIBLE BY LATE TODAY. NE WINDS WILL INCREASE AND GUST TO 25 OR 30 KT NEAR THE COAST WITH LOWER SPEEDS INLAND...BEFORE DIMINISHING TONIGHT. AREAS OF MVFR TUESDAY IN SNOW SHOWERS. LONG TERM...UPPER TROF PIVOTS OVER THE REGION THRU WED...WITH AREAS OF SHSN LIKELY. LOCAL IFR CONDITIONS ARE POSSIBLE IN ANY SHSN...AND THEY WILL BE POSSIBLE AT ANY TERMINAL. STRONG COLD FNT APPROACHES THE AREA FRI...AND COULD BRING GUSTY NWLY WINDS AND A BRIEF SHSN TOO. && .MARINE... SHORT TERM...WINDS AND SEAS WILL BUILD TODAY INTO NIGHT WITH GALES EXPECTED AS OCEAN LOW PASSES BY TO OUR SOUTHEAST LATE TODAY. CONDITIONS WILL DROP BELOW GALE OVERNIGHT WITH LINGERING SMALL CRAFT CONDITIONS OUTSIDE THE BAYS FOR LATE TONIGHT AND TUESDAY. LONG TERM...EXTENDED PERIOD OF SCA CONDITIONS APPEARS LIKELY THRU THE END OF THE WEEK. WINDS AND SEAS WILL GRADUALLY SUBSIDE IN THE WAKE OF DEPARTING LOW PRES TUE. AFTER A BRIEF RELAXATION OF WINDS...A STRONG COLD FNT WILL APPROACH THE WATERS FOR THE WEEKEND...WITH GUSTY NW WINDS POSSIBLE. && .TIDES/COASTAL FLOODING... A 1 TO 1.5 FOOT STORM SURGE WILL COMBINE WITH HIGH ASTRONOMICAL TIDES AND MODESTLY BUILDING SEAS OF 5 TO 10 FEET. THIS MAY LEAD TO MINOR COASTAL FLOODING OR SPLASH-OVER ALONG THE COAST OF YORK AND ROCKINGHAM COUNTIES NEAR THE TIME OF THE MID MORNING HIGH TIDE TODAY. && .GYX WATCHES/WARNINGS/ADVISORIES...
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ME...WINTER WEATHER ADVISORY UNTIL NOON EST TUESDAY FOR MEZ007>009- 012>014. WINTER WEATHER ADVISORY UNTIL NOON EST TUESDAY FOR MEZ018>028. COASTAL FLOOD ADVISORY UNTIL NOON EST TODAY FOR MEZ023. NH...WINTER WEATHER ADVISORY UNTIL 6 AM EST TUESDAY FOR NHZ003>013- 015. WINTER WEATHER ADVISORY UNTIL NOON EST TUESDAY FOR NHZ001-002. COASTAL FLOOD ADVISORY UNTIL NOON EST TODAY FOR NHZ014. WINTER STORM WARNING UNTIL 6 AM EST TUESDAY FOR NHZ014. MARINE...GALE WARNING UNTIL MIDNIGHT EST TONIGHT FOR ANZ150>154.
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&& $$ NEAR TERM...HANES

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