Area Forecast Discussion
Issued by NWS Portland, ME

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290 FXUS61 KGYX 032028 AFDGYX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 328 PM EST WED FEB 3 2016 .SYNOPSIS... A COLD FRONT WILL CROSSES THE REGION TONIGHT WITH RAIN CONTINUING THROUGH THE EVENING. SOME GUSTY WINDS ARE POSSIBLE AS WELL. COLDER AIR WILL GRADUALLY FILTER INTO THE REGION BEHIND THE DEPARTING STORM SYSTEM AS HIGH PRESSURE BUILDS BY TO OUR SOUTH THURSDAY AND FRIDAY. A COLD FRONT WILL CROSS THE REGION SUNDAY. THERE IS A CHANCE THAT A COASTAL STORM AFFECTS THE REGION EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS LOW PRES PULLS INTO SRN CANADA...PRECIP CONTINUES ACROSS MOST OF THE FORECAST AREA AT THIS HOUR. PLYMOUTH STATE LIDAR AND DUAL- POL VARIABLES CONFIRM THAT WARMTH ALOFT HAS JUST ABOUT INVADED THE ENTIRE FORECAST AREA. SFC TEMPS HAVE CONTINUALLY CREPT UP TODAY IN WAA REGIME...WITH ONLY A FEW POCKETS IN NRN NH AND WRN ME MTNS REMAINING AT OR BELOW FREEZING. WILL CONTINUE THE WINTER WX ADVISORIES TO EXPIRATION FOR THESE AREAS. HOWEVER...BULK OF ACCUMULATING WINTRY PRECIP APPEARS TO BE OVER. THE EWD MOVEMENT OF THE PRECIP WILL CONTINUE TO SLOW DOWN AS IT NEARS THE COAST...SO POP WILL BE A SLOW TREND DOWNWARD THRU 06Z. TEMP FORECAST TONIGHT IS NON-DIURNAL...AND I LEANED HEAVILY ON CURRENT OBS TO BLEND THE MODELED TRENDS FOR TONIGHT. COLD AIR DAMMING HAS HELD TOUGH...AND ONLY A SLOW RISE IS EXPECTED OVERNIGHT. THE STABLE LOW LEVELS AND SWLY FLOW OVER THE TOP OF THE COOL...MOIST DOME COULD LEAD TO FOG AND DRIZZLE TONIGHT...ESPECIALLY S OF THE MTNS. FINALLY...REGARDING THE LOW LEVEL JET...WINDS WILL CONTINUE TO INCREASE ALOFT THRU THIS EVENING. STRONG WINDS WILL EXTEND DOWN TO JUST A COUPLE THOUSAND FT OFF THE SFC. HOWEVER...THAT VERY STABLE LOW LEVEL INVERSION WILL PREVENT THE BULK OF THIS FROM REACHING THE GROUND. THAT BEING SAID...THE JET MAXIMIZES AROUND THE MIDCOAST...AND GETS BELOW 1000 FT FOR A TIME. MECHANICAL MIXING ALONE MAY BE ENOUGH FOR A FEW GUST TO 50 MPH NEAR THE COAST. SO THE WIND ADVISORY WILL REMAIN IN EFFECT FOR THE TIME BEING. && .SHORT TERM /THURSDAY AND THURSDAY NIGHT/... S/WV TROF SHEARING OUT TO THE NE WILL HANG THE BAROCLINIC ZONE UP JUST OFF THE COAST THU. THIS SHOULD KEEP ERN ZONES MOSTLY CLOUDY...AND SUBTLE RIPPLES ALONG THE BOUNDARY COULD BRING A FEW ISOLATED SHOWERS TO COASTAL AREAS. LATE THU NIGHT A SECONDARY S/WV TROF MAY AMPLIFY ENOUGH TO START PULLING PRECIP BACK TOWARDS NEW ENGLAND COASTLINE. WILL INCREASE POP FROM PREVIOUS FORECAST...AS MODEL GUIDANCE HAS TRENDED WWD WITH FORCING. AS FOR TEMPS...THU WILL BE QUITE MILD AS TRUE COLD FNT IS SLOW TO WORK THRU THE AREA. COLD AIR BLEED FINALLY ARRIVES THU NIGHT...WITH TEMPS DROPPING BELOW FREEZING...BUT STILL REMAINING ABOVE NORMAL. && .LONG TERM /FRIDAY THROUGH TUESDAY/... HIGH IMPACT WX: POSSIBLE COASTAL STORM EARLY NEXT WEEK. CHANGES INT HE HEMISPHERIC 500 MB PATTERN ARE MORE ABOUT AMPLIFICATION AND BLOCKING OVER THE EXTENDED FORECAST....WITH THE UNSTABLE AND WEAKLY AMPLIFIED +PNA BECOMING MORE AMPLIFIED AS WE MOVE THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. THIS WILL ALLOW FOR SEVERAL TROUGHS TO DEVELOP OVER THE MIDDLE OF NOAM AND LOW COLDER AIR TO GRADUALLY FILTER EQUATORWARD OUT OF NRN CANADA. THE PERSISTENT FLOW OF SHORT WAVE TROUGHS WILL ALSO GRADUALLY CARVE OUT A LARGER SCALE TROUGH OVER THE ERN HALF OF THE CONUS...WHICH WILL BRING SOMEWHAT UNSETTLE CONDS TO NEW ENGLAND THROUGH THE MIDDLE OF NEXT WEEK. WILL BEGIN FRI WITH THE POTENTIAL OF SOME SHRA/SN NEAR THE COAST AS WEAK WAVE MOVES ALONG STALLED FRONT OFFSHORE. MODELS VARY A BIT AS TO WHETHER PRECIP SPREADS NW INTO THE COASTAL AREAS...AND HAVE CHC POPS ALONG THE IMMEDIATE COAST THRU FRI MORNING BEFORE THE SYSTEM BEGINS TO HEAD EWD IN THE AFTERNOON. WEAK HIGH PRESSURE BUILDS TO OUR S FRI NIGHT AND SAT WITH WEAK RIDGING AT 500 MB. THE NEXT 50 MB TROUGH CROSS NRN AREAS SAT NIGHT AND SUN AND DRAGS A COLD FRONT ACROSS THE REGION LATE SUN AND SUN NIGHT. THIS COULD SET OFF ANOTHER ROUND SHSN IN THE MTNS...WITH AN OUTSIDE CHC FOR SOME SHRA TOWARD THE COAST. FORECAST CONFIDENCE HAS ACTUALLY DECREASED FOR EARLY NEXT WEEK AS 12Z GFS AND 12Z EURO DIVERGE ON THE EVOLUTION OF TWO COASTAL SYSTEMS. THE GFS SLIDES THE FIRST SYSTEM WELL TO OUR S AND E ON MONDAY...AND BRINGS A COASTAL LOW THRU THE GULF OF ME TUESDAY...WHICH WOULD PRODUCE SOME ACCUMULATING SNOW CENTERED AROUND TUE. THE 12Z EURO PUSHES THE 500 MB SYSTEMS ON MONDAY AND PULLS THAT FIRST BACK TO THE WEST ON MONDAY AND SLIDES THE SECOND SYSTEM TO OUR S AND E ON TUESDAY. SINCE BOTH MODELS ARE DEVELOPING COASTAL LOWS NOT TOO FAR OFFSHORE...THE SITUATION BEARS WATCHING...BUT TIMING...ACCUMS AND ANY OTHER IMPACTS REMAIN UNCERTAIN. TEMPS WILL GENERALLY BE ABOVE NORMAL THROUGH THE WEEKEND...WITH SOME COOLING ON FIR...BUT HIGHS STILL SEVERAL DEGREES ABV NORMAL RANGING FROM NEAR 30 IN THE N TO THE UPPER 30S ALONG THE COAST AND IN SRN NH. SW FLOW ALLOWS TEMPS TO WARM UP AGAIN ON SAT...WITH PARTLY TO MOSTLY SUNNY SKIES. HIGHS WILL BE IN THE LOW 30S TO MID 40S. DESPITE MORE CLOUDS ON SUNDAY TEMPS SHOULD BE SIMILAR TO SAT. TEMPS EARLY NEXT WEEK WILL COLD DOWN BEHIND THE COLD FRONT...BUT SHOULD COME IN NEAR NORMAL...OR MAYBE SLIGHTLY BELOW DEPENDING UPON THE EFFECTS OF ANY COASTAL LOWS. && .AVIATION /20Z WEDNESDAY THROUGH MONDAY/... SHORT TERM...FAIRLY WIDESPREAD IFR CONDITIONS WILL CONTINUE IN RNFL ACROSS THE FORECAST AREA INTO EARLY EVENING. FORECAST IS A LITTLE TRICKY FOR THE OVERNIGHT...BASED ON WHETHER AREAS OF FG/DZ DEVELOP AS FORECAST. DRY SLOT MOVES OVERHEAD AND WEAK LIFT CONTINUES...SO THE ATMOSPHERE WILL BE PRIMED FOR DZ. BUT OCCASIONAL SHRA NEAR THE COAST MAY INTERRUPT WIDESPREAD DEVELOPMENT. COLD AIR DAMMING IS ALSO KEEPING THE LOW LEVELS VERY STABLE...SO LLWS WILL PERSIST OVERNIGHT AS SWLY FLOW ALOFT REMAINS STRONG. GRADUAL IMPROVEMENT TO VFR THU...THOUGH AN ISOLATED SHRA POSSIBLE FOR COASTAL TERMINALS IS POSSIBLE. LONG TERM...POSSIBLE FLIGHT RESTRICTIONS ALONG THE COAST FRI MORNING IN -SN...OTHERWISE EXPECT VFR THROUGH SAT. COULD SEE TEMP RESTRICTIONS IN SHSN SAT NIGHT INTO SUNDAY...MAINLY IN THE MTNS. && .MARINE... SHORT TERM...SLY JET VEERING TO SSWLY WILL CONTINUE TO INCREASE INTO THE EVENING. GALE FORCE GUSTS WILL BECOME MORE FREQUENT...WITH A FEW GUSTS TO NEAR 45 KTS ON THE OUTER WATERS. WINDS AND SEAS WILL GRADUALLY DIMINISH THU...THOUGH SCA CONDITIONS WILL CONTINUE THRU THE DAY. LONG TERM...FREQUENT SCA CONDITIONS EXPECTED SAT THRU MONDAY...WITH SW FLOW SHIFTING TO N SUN NIGHT. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR MEZ027-028. WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MEZ007>009-014. NH...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR NHZ001. MARINE...GALE WARNING UNTIL 3 AM EST THURSDAY FOR ANZ150>154. && $$ NEAR TERM...LEGRO SHORT TERM...LEGRO LONG TERM...CEMPA

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