Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 251556 AAA AFDGYX AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GRAY ME 1056 AM EST TUE NOV 25 2014 .SYNOPSIS... A COLD FRONT CONTINUES TO PUSH OFFSHORE THIS MORNING. THE FRONT WILL STALL OVER THE MID ATLANTIC COAST TUESDAY AND TUESDAY NIGHT AS WEAK HIGH PRESSURE BUILDS OVER NEW ENGLAND. LOW PRESSURE WILL DEVELOP ON THE FRONT OFF THE MID ATLANTIC COAST ON WEDNESDAY AND TRACK NORTHEAST TO JUST SOUTH OF CAPE COD BY WEDNESDAY EVENING. THE COASTAL LOW WILL CONTINUE NORTHEAST INTO THE MARITIMES WEDNESDAY NIGHT. A TROUGH OF LOW PRESSURE WILL LINGER OVER THE REGION ON THURSDAY. HIGH PRESSURE WILL BUILD IN FROM THE WEST ON FRIDAY. A WARM FRONT LIFTS INTO THE REGION FROM THE SOUTHWEST ON SATURDAY...FOLLOWED BY A COLD FRONTAL PASSAGE ON SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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UPDATE...MINOR CHANGES TO THE FORECAST FOR TODAY. RAISED MIN TEMPS A COUPLE DEGREES ALONG THE COAST...AS COLD FNT WILL TAKE A COUPLE HOURS TO GET THRU.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
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UPDATE...EARLY LOOK AT THE 12Z AMERICAN MODEL GUIDANCE SHOWS NO SIGNIFICANT CHANGE FROM OVERNIGHT FORECAST. THERE IS AN EXCELLENT CONSENSUS OF MODEL GUIDANCE A SHADE NW OF THE 40N/70W BENCHMARK...WITH THE CMC BEING THE LONE ERN OUTLIER. THIS IS A FAVORABLE SNWFL TRACK FOR NRN NEW ENGLAND. COLUMN CONTINUES TO BE PLENTY COLD ENOUGH FOR SNWFL AT SOME POINT IN THE STORM. QUESTIONS STILL REMAIN ABOUT SFC TEMPS NEAR THE COAST AND SRN NH...AS WELL AS HOW MUCH WARMING ALOFT MAKES IT NWD TOWARDS THE FORECAST AREA. ATTM ABOVE FREEZING AIR ALOFT APPEARS AS IF IT WILL REMAIN S OF THE AREA...HOWEVER NEAR FREEZING TEMPS COULD LEAD TO A PERIOD OF POOR SN GROWTH. ALSO DESPITE HIGH QPF FOR THE SE HALF OF THE FORECAST AREA...GFS...NAM...AND ECMWF FORECAST TRACKS FOR MID LEVEL LOW PRES CENTERS ARGUES THAT SOME DRY SLOT OR DESATURATION ISSUES MAY ARISE WED EVENING. HAVE ADDED A LITTLE FREEZING DRIZZLE TO GIVE A NOD IN THIS DIRECTION...AND ALSO DROPPED SN RATIOS...AND THEREFORE SNWFL AMOUNTS...NEAR THE COAST. HOWEVER...MID LEVEL LOW TRACKS ALSO LINE UP QUITE FAVORABLE FOR STRONGER FRONTOGENESIS AND BANDING JUST INLAND FROM THE COAST. SO TOTALS HERE HAVE INCREASED SLIGHTLY. THERE IS PLENTY MORE DATA TO SIFT THRU...SO WINTER STORM WATCHES WILL REMAIN IN PLACE WITH THIS UPDATE. PREVIOUS DISCUSSION...MODELS ARE CONSISTENT IN KEEPING PRECIPITATION OFFSHORE UNTIL NEARLY DAYBREAK WHEN JUST A FEW WARM ADVECTION SHOWERS MAY REACH THE SHORE IN ASSOCIATION WITH THE THANKSGIVING STORM. WE SHOULD SEE INCREASING CLOUDINESS HOWEVER WITH OVERNIGHT LOWS IN THE UPPER 20S AND 30S...WITH TEMPERATURES INCREASING TOWARDS MORNING. LOW PRESSURE HEADS UP THE EAST COAST ON WEDNESDAY. MODELS IN FAIRLY GOOD AGREEMENT IN BRINGING LOW PRESSURE TO THE SOUTHEAST OF CAPE COD BY 00Z THURSDAY. AFTER THAT ECMWF A LITTLE SLOWER AND DEEPER THROUGH 12Z THURSDAY. GENERAL TREND PAST COUPLE OF NIGHTS HAS SHOWN THE ECMWF DRIFTING TOWARD THE GFS SOLUTION WHICH HAS BEEN CONSISTENTLY COLDER...QUICKER AND WITH LESS QPF. ALTHOUGH BOUNDARY LAYER TEMPS MAY INITIALLY BE WARM ENOUGH TO SUPPORT RAIN OR A MIX IN COASTAL AREAS...VERY DRY AIR IN PLACE AT LOWER TO MID LEVELS WILL QUICKLY COOL AND EXPECT ANY MIXED PRECIP AT THE ONSET TO GO OVER TO SNOW. THIS SHOULD PUSH INTO SOUTHERN ZONES DURING THE MID TO LATE MORNING DEPENDING ON HOW LONG IT TAKES TO SATURATED THE LOWER AND MID LEVELS. SNOW WILL GRADUALLY OVERSPREAD THE REMAINDER OF THE FORECAST AREA THROUGH MID AFTERNOON. BIG QUESTION THEN BECOMES QPF AND AXIS OF HEAVIEST PRECIPITATION. ECMWF SLOWLY TRENDING TOWARD LESSER AMOUNTS IN THE GFS BUT SOME DIFFERENCES PERSIST. THIS DIFFERENCE PROBABLY DUE TO SLOWER AND SLIGHTLY DEEPER ECMWF SOLUTION AND THE SUGGESTION OF SOME WEAK BANDING SETTING UP ALONG THE COAST...WHICH THE GFS IS HINTING AT BUT FURTHER EAST AND WEAKER. WILL TRY TO FIND A COMPROMISE BETWEEN THE TWO FOR NOW. THIS WOULD GIVE MUCH OF THE FORECAST AREA SOUTH OF THE MOUNTAINS AND EAST OF THE CONNECTICUT VALLEY WARNING CRITERIA SNOWFALL. WITH WATCHES UP AND CONTINUING UNCERTAINTY...SEE NO REASON TO RUSH WARNINGS. WILL LET THE DAY SHIFT HAVE A LOOK AT THE NEXT MODEL RUNS AND REFINE THE WARNING AREA FROM THERE. LOW PRESSURE WILL QUICKLY RACE NORTHEAST INTO THE MARITIMES WEDNESDAY NIGHT. EXPECT STEADIER HEAVIER PRECIP TO SHIFT EAST AFTER MIDNIGHT LEAVING JUST OCCASIONAL LIGHT SNOW IN IT`S WAKE. LOWS TEMPS ACROSS THE AREA WILL RANGE THROUGH THE 20S. TROUGH OF LOW PRESSURE WILL LINGER OVER THE REGION ON THANKSGIVING DAY KEEPING SNOW SHOWERS IN THE FORECAST DURING THE DAY AND INTO THURSDAY NIGHT. NOT LOOKING FOR MUCH IN THE WAY OF QPF BUT SOME LOCATIONS MAY SEE SOME LIGHT ACCUMS IN THE AFTERNOON AS A WEAK SHORTWAVE SWINGS THROUGH. WITH A FRESH SNOW PACK WILL SEE TEMPS RETURN TO BELOW NORMAL READINGS WITH HIGHS RANGING FROM THE MID 20S TO MID 30S.
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&& .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... TROUGHING REMAINS OVERHEAD THURSDAY NIGHT AND FRIDAY. SNOW SHOWERS TAPER OFF OVER MUCH OF THE AREA BUT KEPT SOME LIGHT SNOW SHOWERS MAINLY OVER THE MOUNTAINS AND OFF THE COAST. COLDER AIR FILTERS IN AS EARLY AS THURSDAY NIGHT WITH OVERNIGHT LOWS IN THE TEENS. TEMPERATURES WILL DEPEND ON HOW FAST THE CLOUD COVER IS SCOURED OUT...AND FOR NOW HAVE KEPT AREAS OUTSIDE THE MOUNTAINS IN THE 20S. FRIDAY NIGHT LOOKS TO BE ONE OF THE COLDEST NIGHTS SO FAR THIS YEAR...WITH MANY AREAS IN THE SINGLE DIGITS...AND TEENS ALL THE WAY TO THE COAST. COLD AIR REMAINS DAMMED ALONG THE HIGHER TERRAIN FRIDAY AND SATURDAY WITH SOME MODERATION SUNDAY AHEAD OF A COLD FRONT. IT WILL STILL BE COLD ENOUGH FOR SNOW SHOWERS HOWEVER...BUT THE FRONTAL SYSTEM MOVES THROUGH QUICKLY AND DROPS SOME LIGHT PRECIPITATION OVER THE MOUNTAINS. HIGH PRESSURE MOVES IN BEHIND THIS SYSTEM FOR EARLY NEXT WEEK...BUT THE PATTERN REMAINS FICKLE WITH A SYSTEM AFFECTING NEW ENGLAND EVERY 1-2 DAYS. && .AVIATION /16Z TUESDAY THROUGH SATURDAY/... SHORT TERM...PLENTY OF CIRRUS DEBRIS FROM STORMS MOVING ALONG A FRONT CURRENTLY OFFSHORE HAS MADE IT TO NORTHERN NEW ENGLAND. UNDER THIS DENSE FOG HAS FORMED IN A FEW SPOTS AND THE UPPER LEVEL CLOUDS AREN`T INHIBITING THE RADIATION MUCH IF ANY. FOG SHOULD DISSIPATE AFTER SUNRISE. SSW HAVE WEAKENED FINALLY BUT WILL INCREASE AFTER MIXING RESUMES MID MORNING WITH WINDS MORE WSW. OTHERWISE VFR. LONG TERM...PERIOD OF LOW CEILINGS AND VISIBILITIES BEGINNING MIDDAY WEDNESDAY THROUGH THURSDAY AS A COASTAL STORM DROPS HEAVY SNOW AND PERHAPS INITIALLY RAIN OR MIXED PRECIPITATION. ALL TERMINALS WILL BE AFFECTED BY THE STORM WITH CONDITIONS LIFR FOR A STRETCH BETWEEN 20Z WEDNESDAY AND 12Z THURSDAY. && .MARINE... SHORT TERM...ALL MARINE ZONES NOW UNDER SMALL CRAFT ADVISORIES THROUGH LATE WEDNESDAY NIGHT. LONG TERM...GALES WILL DEVELOP WEDNESDAY NIGHT INTO THURSDAY FOR THE OUTER WATERS. SCAS WILL LIKELY BE NEEDED FOR THE BAYS FOR WINDS AND SEAS. && .GYX WATCHES/WARNINGS/ADVISORIES...
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ME...WINTER STORM WATCH FROM WEDNESDAY AFTERNOON THROUGH LATE WEDNESDAY NIGHT FOR MEZ007>009-012>014-018>028. NH...WINTER STORM WATCH FROM WEDNESDAY AFTERNOON THROUGH LATE WEDNESDAY NIGHT FOR NHZ001>010-013-014. MARINE...GALE WATCH FROM WEDNESDAY AFTERNOON THROUGH LATE WEDNESDAY NIGHT FOR ANZ150>154.
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&& $$ UPDATE...LEGRO

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