Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 170812 AFDGYX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 312 AM EST WED DEC 17 2014 .SYNOPSIS... A WEAK LOW PRESSURE SYSTEM WILL MOVE INTO THE GULF OF MAINE TODAY AND START TO INTENSIFY THIS AFTERNOON...SPREADING RAIN AND SNOW OVER THE REGION. BY THURSDAY MORNING THE LOW WILL BE OVER THE CANADIAN MARITIMES AND WEAK HIGH PRESSURE WILL BUILD IN BEHIND IT. THERE IS POTENTIAL FOR A WEAK COASTAL STORM SUNDAY INTO MONDAY THAT MAY SPREAD SOME LIGHT SNOW INTO THE REGION. A MUCH STRONGER STORM MAY AFFECT THE REGION MIDWEEK. && .NEAR TERM /UNTIL 6 PM TONIGHT/... LIGHT OVERRUNNING PRECIPITATION ONGOING THIS MORNING AS A WARM FRONT LIFTS INTO THE AREA. WARM AIR ALOFT MOVING OVER AREAS OF FREEZING AIR AT THE SURFACE HAS RESULTED IN PATCHY FREEZING RAIN. OTHER LOCATIONS REMAIN ABOVE FREEZING. THIS TREND WILL CONTINUE WITH A MIX OF PRECIPITATION EARLY THIS MORNING ACROSS THESE AREAS BEFORE ALL BUT THE FAR NORTHERN AREAS CHANGE OVER TO RAIN BY EARLY AFTERNOON. NORTHERN NH AS WELL AS NORTHERN MAINE AND THE FOOTHILLS REMAIN UNDER FREEZING RAIN AND WINTER WEATHER ADVISORIES THROUGHOUT THE MORNING. LOW PRESSURE FORMS ALONG THE COAST TODAY...SETTING UP A BAROCLINIC ZONE NEAR THE LAND/SEA INTERFACE. EXPECT UPPER 30S AND 40S AREAWIDE TODAY WITH THE WARMEST TEMPERATURES JUST SOUTH OF THIS BOUNDARY. && .SHORT TERM /6 PM TONIGHT THROUGH 6 PM THURSDAY/... THE COASTAL SURFACE LOW UNDERGOES RAPID DEEPENING... MOVING NE AND DRAWING COLD AIR INTO NORTHERN NEW ENGLAND TONIGHT AND THURSDAY. STRONG UPPER LEVEL CANON BALL LOW PRESSURE CLOSING OFF OVER NORTHERN NEW ENGLAND WILL PROVIDE PLENTY OF LIFT AND DYNAMICS FOR A HEAVY SNOWFALL AS IT EXITS THE AREA. IN FACT...NORTHERN OXFORD...NORTHERN FRANKLIN AND CENTRAL SOMERSET REMAIN IN AN ADVISORY THROUGH LATE VERY LATE TONIGHT AS THE DOMINANT P TYPE CHANGES TO SNOW. THE POSSIBILITY OF STORM TOTAL AMOUNTS AT OR ABOVE HALF A FOOT IS ESPECIALLY LIKELY THE FARTHER NE YOU GO. SOMERSET COUNTY WILL LIKELY GET THESE AMOUNTS BUT WOULD NEED MORE THAN 9" IN 24 HRS TO WARRANT A WARNING...AND CONFIDENCE WAS NOT HIGH ENOUGH IN THIS SCENARIO. RAIN AND SNOW SHOWERS TAPER OFF TOMORROW FROM SOUTHWEST TO NORTHEAST AS THE LOW MOVES AWAY. TOTAL SNOWFALL AMOUNTS SHOULD BE LESS THAN 2" SOUTH OF THE MOUNTAINS AS THE SNOW MIXES WITH RAIN AT TIMES. HIGH TEMPERATURES SHOULD REACH THE 40S ALONG THE COAST AND SOUTH WITH LOWER TO MID 30S NORTH AND EAST. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... START OFF THURSDAY NIGHT WITH LOW PRESSURE OVER THE CANADIAN MARITIMES AND CONTINUING TO PULL OFF TO THE NORTHEAST. WEAK HIGH PRESSURE AND FAIR WEATHER IS THEN EXPECTED FRIDAY THROUGH SUNDAY MORNING. MODELS THEN DIVERGE AFTER SUNDAY. THE GFS AND GEM SHOW A WEAK COASTAL LOW FOR SUNDAY NIGHT INTO MONDAY MORNING. THE 00Z GFS NOW DEVELOPS THE LOW SOUTH AND EAST OF NOVA SCOTIA...PUTTING IT TOO FAR OUT TO HAVE REALLY ANY IMPACT...BUT IT DOES HAVE AN INVERTED TROUGH EXTENDING BACK TO MAINE THAT MAY BRING SOME LIGHT SNOW TO THE AREA. THE GEFS MEAN SHOWS A SIMILAR SOLUTION AS THE OPERATIONAL GFS WITH ONLY SOME VERY LIGHT SNOW. THE GEM DEVELOPS THE LOW IN A SIMILAR LOCATION AS THE GFS...YET ITS A BIT FURTHER EAST AND A LITTLE DEEPER. THE GEM ALSO SHOWS THE INVERTED TROF REACHING BACK TO MAINE...BUT IT IS MORE AMPLIFIED THAN THE GFS. DEPENDING ON THE AXIS OF THIS TROF...SOME AREAS WOULD SEE A PLOWABLE SNOWFALL. THE 00Z EURO COMPLETELY LOST THE SYSTEM AND INSTEAD DEVELOPS A COASTAL LOW SOUTH OF LONG ISLAND MONDAY NIGHT AND TRACKS IT INTO THE GULF OF MAINE BY EARLY TUESDAY MORNING. AT THIS TIME WITH THE UNCERTAINTY...I WENT WITH JUST CHANCE POP FOR SUNDAY INTO MONDAY AND SLIGHT CHANCE FOR MONDAY NIGHT INTO TUESDAY WITH STILL VERY LOW CONFIDENCE IN THIS FORECAST. FINALLY THE EURO AND GFS ARE STILL SHOWING A LARGE STORM FOR CHRISTMAS EVE AND/OR CHRISTMAS DAY...HOWEVER WHERE IT WILL BE AND TRACK TO IS STILL ANYONES GUESS. WE WILL CONTINUE TO MONITOR THE POTENTIAL OVER THE NEXT SEVERAL DAYS. THERE IS ALREADY A LOT OF RUN TO RUN DISCONTINUITY COMING WITH THE LOCATION OF THE LOW AND THIS FAR OUT THAT IS EXPECTED...AS BOTH MODELS JUST WENT FROM A COASTAL LOW WITH THE 12Z RUNS TO A WARM CUTTER WITH THE 00Z RUNS. SO ALL WE CAN DO AT THIS TIME IS SEE HOW IT EVOLVES AS WE HEAD INTO NEXT WEEK...AS THE ENERGY TO DEVELOP THIS STORM WILL NOT EVEN BE SAMPLED WITH REAL DATA FOR SEVERAL DAYS YET. && .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... SHORT TERM...DETERIORATION TO IFR AND LIFR ALREADY OCCURRING IN DRIZZLE...RAIN...SNOW...AND FOG. SLIGHT CHC FOR SOME FZRA AT KLEB AND KHIE. THE IFR/LIFR PERSISTS THROUGH THE MORNING HOURS. SOME IMPROVEMENT TO CEILINGS TO IFR THIS AFTERNOON BUT PRECIPITATION EVENT CONTINUES AND WILL KEEP CONDITIONS FROM BECOMING MVFR. EXPECT WORSENING CONDITIONS IN WIDESPREAD SNOW AS TEMPERATURES DROP AT NIGHT. LONG TERM...THURSDAY THROUGH SUNDAY...VFR CONDITIONS MOST AREAS WITH POSSIBLE MVFR TO IFR CONDITIONS IN THE MOUNTAINS OVERNIGHT THURSDAY. SHOULD BE MOSTLY VFR CONDITIONS THROUGH AT LEAST SUNDAY MORNING AND THEN THERE IS POTENTIAL FOR SOME LOWER CONDITIONS DUE TO A WEAK COASTAL LOW THAT COULD PROVIDE LIGHT SNOW OR WINTRY MIX SUNDAY AFTERNOON THROUGH SUNDAY NIGHT. && .MARINE... SHORT TERM...SMALL CRAFT CONDITIONS CONTINUE TODAY BUT SHOULD BE A QUIET PERIOD TONIGHT BEFORE WIND GUSTS PICKUP AGAIN TOMORROW MORNING. WHETHER THIS WILL BE TAKEN ADVANTAGE OF OR THE ENTIRE TIME FRAME BRIDGED WITH AN ADVISORY HAS BEEN LEFT TO THE SUBSEQUENT SHIFT. LONG TERM...SCA CONDITIONS EXPECTED THURSDAY NIGHT INTO EARLY FRIDAY AS LOW PRESSURE DEPARTS TO THE NORTHEAST OF THE WATERS. CONDITIONS WILL THEN SUBSIDE. SCA COULD BE POSSIBLE LATE SUNDAY INTO MONDAY DEPENDING WHERE A COASTAL LOW PRESSURE TRACK AND INTENSITY...HOWEVER AT THE MOMENT IT APPEARS IT WILL NOT INTENSIFY UNTIL IT GETS UP INTO THE CANADIAN MARITIMES. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR MEZ007-012-013. WINTER WEATHER ADVISORY UNTIL 6 AM EST THURSDAY FOR MEZ008-009- 014. NH...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR NHZ001-002-004. FREEZING RAIN ADVISORY UNTIL 8 AM EST THIS MORNING FOR NHZ003- 005. MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ150- 152-154. && $$ HANES/KISTNER

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