Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 151652 AFDGYX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 1152 AM EST MON DEC 15 2014 .SYNOPSIS... HIGH PRESSURE WILL MOVE OVER THE REGION TODAY THEN SHIFT EAST INTO THE CANADIAN MARITIMES ON TUESDAY. WEAK LOW PRESSURE MOVES OFFSHORE TUESDAY NIGHT INTO WEDNESDAY...AND WILL BRING A ROUND OF LIGHT PRECIPITATION. GUSTY NW WINDS FOLLOW BEHIND EXITING LOW PRESSURE FRIDAY. HIGH PRESSURE WILL BUILD INTO THE REGION TOWARD THE BEGINNING OF THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1145 AM...UPDATE TO BRING MAX T UP A BIT IN THE DOWNSLOPE AREAS WHERE THERE IS PLENTY OF SUN...AND BRING THEM DOWN A BIT IN THE MTNS WHERE THE LOW CLOUDS ARE LOCKED IN. NW WINDS DIMINISHING THIS MORNING AS THE RIDGE MOVES OVERHEAD...AND LOW SUN ANGLE IS NOT LKLY TO MIX OUT THE CLOUDS MUCH THIS AFTERNOON...BUT INCREASING SW BOUNDARY LYR FLOW BEHIND THE RIDGE MAY HELP OUT LATE TODAY AND THIS EVENING. 615 AM UPDATE: NO NEED FOR ANY CHANGES TO THE PREV FCST. LOW LEVEL CLOUDS CONTINUE IN THE MOUNTAINS AND WRN NH WITH CLEAR SKIES ELSEWHERE. STILL EXPECTING THESE LOW CLOUDS TO DISSIPATE LATER THIS MORNING AS THE MIXES OUT THE LOW LEVEL INVERSIONS WHERE THE MOISTURE/CLOUDS ARE TRAPPED. PREV DISC: HIGH PRESSURE SETTLES OVER THE REGION TODAY. A TRAPPED LAYER OF LOW LEVEL MOISTURE IN THE MOUNTAINS OF ME/NH AND EXTENDS THROUGH WESTERN NH WILL GRADUALLY MIX OUT BY MID MORNING...ELSEWHERE SUNNY SKIES EXPECTED WITH LIGHT WINDS AND MILD TEMPS. STAYED CLOSE TO GUID FOR MAX TEMPS. && .SHORT TERM /TONIGHT THROUGH 6 PM TUESDAY/... THE SFC/UPR HIGH PRES AXIS WILL EXTEND N-S ACROSS THE FA AND WILL START OUT THE NIGHT GIVING CLEAR SKIES FOLLOWED BY INCREASING CLOUDS LATER TONIGHT. ON TUESDAY CLOUDS OVERSPREAD THE REGION AS THE RIDGE AXIS MOVES OFF TO THE EAST ALLOWING A MOIST ONSHORE LOW LEVEL FLOW TO DEVELOP AS WELL AS THE MID/HI CLOUDS APPROACHING FROM THE W THAT WILL SPILL ACROSS THE UPPER RIDGE. SOME LIGHT SCT SHOWERS MAY DEVELOP LATER IN THE DAY OVER SRN AREAS MAINLY DUE TO THE LOW LEVEL FLOW OFF THE OCEAN. USED A BLEND OF MODEL GUID FOR BOTH POPS AND TEMPS TONIGHT AND TUE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... BY WEDNESDAY THE UPPER LEVEL PATTERN BECOMES SKEWED WITH PARENT LOW PRESSURE HANGING UP OVER THE GREAT LAKES REGION AND THE BASE OF THE TROUGH SWINGING OUT TOWARDS THE ATLANTIC. AN OPEN WAVE TRAVELING ALONG THE TROUGH BRINGS THE NEXT CHANCE OF PRECIPITATION TO NEW ENGLAND ON WEDNESDAY. WARM AIR ADVECTION WILL HAVE ALREADY BEGUN WEDNESDAY MORNING AS A SURFACE LOW TRIES TO FORM ALONG THE NH SEACOAST. WHETHER THIS CIRCULATION FORMS FULLY OR NOT... ISENTROPIC LIFT WILL BRING SOME LIFT TO THE REGION. WARM AIR MOVING OVER A COLDER SURFACE WILL INTRODUCE THE LIKELIHOOD OF A WINTRY MIX OVER THE INTERIOR AND MOUNTAIN SECTIONS. A MIX WILL OCCUR THROUGH THE MORNING HOURS BEFORE TEMPERATURES WARM ENOUGH FOR A CHANGE OVER TO RAIN DURING THE DAY. QPF AMOUNTS WILL BE LIGHT BUT STILL THIS WOULD BE ENOUGH TO CAUSE A MESSY COMMUTE. THE SYSTEM BECOMES MORE ORGANIZED AS IT MOVED OVER THE CANADIAN MARITIMES WITH A MORE SUBSTANTIAL SHORTWAVE. WE WILL SEE RESIDUAL UPSLOPE SNOW SHOWERS IN THE MOUNTAINS AND A COLD FRONTAL PASSAGE THURSDAY. THIS WILL BRING DAILY HIGHS DOWN A FEW DEGREES FROM THE UPPER 30S NORTH AND LOWER 40S SOUTH TO THE MID 20S NORTH TO MID 30S SOUTH. COLD AIR BECOMES DAMMED TO THE NORTH...AND AREAS ALONG THE CANADIAN BORDER WILL SEE LOWS IN THE TEENS TOWARDS THE END OF THE WORK WEEK. AFTER A GUSTY FRIDAY POST FRONTAL... HIGH PRESSURE BUILDS IN BRIEFLY FOR SATURDAY. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... SHORT TERM...MVFR CIGS AT KLEB/KHIE THROUGH MID MORNING WITH VFR CONDS ELSEWHERE. THIS AFTERNOON THROUGH EARLY TUE CONDS TO REMAIN VFR. BY TUE AFTERNOON VFR CONDS MAY BECOME MVFR IN ANY DEVELOPING SCT SHWRS. LONG TERM...BEGINNING MVFR CONDITIONS IN SCATTERED PRECIPITATION WITH DETERIORATING CONDITIONS TO IFR OR WORSE...ESPECIALLY FOR INLAND TERMINALS IN FROZEN/FREEZING PRECIPITATION WEDNESDAY MORNING. PRECIPITATION SHOULD FALL AS RAIN FOR COASTAL SITES. POOR CONDITIONS MAY CONTINUE INTO THURSDAY DEPENDING ON THE FORMATION OF ADDITIONAL LOW PRESSURE...OTHERWISE SKIES WILL BEGIN TO LIFT AND VISIBILITIES TO IMPROVE BY THURSDAY AFTERNOON. SHOWERS AND MVFR CEILINGS WILL CONTINUE FOR MOUNTAIN TERMINALS THROUGH FRIDAY MORNING. && .MARINE... SHORT TERM...NO FLAGS. LONG TERM...COASTAL LOW PRESSURE MAY DEVELOP AND PASS NEAR THE WATERS IN THE WEDNESDAY THROUGH THURSDAY TIME FRAME. SEAS SHOULD STAY NEAR 5 FT OVER THE OUT WATERS BUT WINDS MAY GUST TO AROUND 30 KTS LATE WEDNESDAY INTO FRIDAY MORNING. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$ SYNOPSIS... NEAR TERM...CEMPA SHORT TERM... LONG TERM... AVIATION... MARINE...

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