Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 271635 AFDGYX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 1135 AM EST SAT DEC 27 2014 .SYNOPSIS... HIGH PRESSURE WILL BUILD SOUTH OF NEW ENGLAND TODAY. A COLD FRONT WILL APPROACH FROM THE WEST TONIGHT AND WILL CROSS THE REGION ON SUNDAY. A LITTLE LIGHT RAIN IS EXPECTED FROM THIS FEATURE...AND PERHAPS A LITTLE LIGHT FREEZING RAIN TONIGHT ACROSS PORTIONS OF THE INTERIOR. COLD HIGH PRESSURE RETURNS AGAIN SUNDAY NIGHT THROUGH MIDWEEK. && .NEAR TERM /THROUGH TONIGHT/... 1130 AM UPDATE...UPDATED TEMPERATURES BASED ON CURRENT OBSERVATIONS AND TRENDS. FAVORABLE UPSLOPE AREAS WILL REMAIN IN THE CLOUDS THIS AFTERNOON...WHILE SOUTH AND EAST OF THE MOUNTAINS WILL SEE MOSTLY SUNNY SKIES AND TEMPERATURES 10 TO 15 DEGREES ABOVE NORMAL. 845 AM UPDATE...MADE SOME ADJUSTMENTS TO TEMPERATURES THIS MORNING AS PARTS OF SW MAINE WERE MORE THAN 5 DEGREES COOLER THAN SURROUNDING SPOTS DUE TO THE CLEAR SKIES AND LIGHT WINDS ALLOWING FOR RADIATIONAL COOLING. BECAUSE THESE AREAS STARTED MUCH COOLER I JUST PULLED THE HIGH TEMPS BACK A DEGREE OR 2...BUT WITH DOWNSLOPING AND CLEAR SKIES WE ARE STILL EXPECTING TEMPS IN THE MID 40S. ALSO...UPDATED SKY COVER BASED ON LATEST VISIBLE IMAGERY...BUT OVERALL THE FORECAST REMAINS ON TRACK. PREVIOUS DISCUSSION... HIGH PRESSURE RIDGING WILL CREST OVER NEW ENGLAND TODAY WHILE A COLD FRONT APPROACHES FROM THE WEST. LOW CLOUDS TRAPPED BENEATH A SUBSIDENCE INVERSION ACROSS THE INTERIOR AND PORTIONS OF THE COASTAL PLAIN WILL HOLD FIRM THROUGH THE EARLY MORNING HOURS BEFORE RETREATING BACK INTO THE MOUNTAINS BY MIDDAY. MAX TEMPS WILL ONCE AGAIN BE ABOVE NORMAL...WITH HIGHS IN THE 40S AT MOST LOCATIONS OUTSIDE OF THE MOUNTAINS. && .SHORT TERM /SUNDAY/... LOW PRESSURE TRACKING NORTHEASTWARD ACROSS ONTARIO AND QUEBEC TONIGHT WILL DRAG A COLD FRONT ACROSS NEW ENGLAND LATE TONIGHT AND SUNDAY MORNING. MOISTURE AND FORCING FOR ASCENT SHOULD BE SUFFICIENT FOR MEASURABLE LIGHT PRECIPITATION TONIGHT MOST AREAS...EXCEPT PERHAPS SOUTHERNMOST ZONES. MUCH OF THIS LIGHT PRECIPITATION SHOULD BE IN THE FORM OF RAIN. HOWEVER...SOME MARGINALLY SUB-FREEZING SFC AIR MAY BECOME TRAPPED IN THE MOUNTAINS AND FOOTHILLS. THIS MAY ALLOW FOR SOME LIGHT FREEZING RAIN FOR A FEW HOURS. HAVE FOLLOWED A BLEND OF MESOSCALE MODEL GUIDANCE FOR OVERNIGHT TEMPERATURES. THIS BLEND INDEED YIELDS A LITTLE LIGHT FREEZING RAIN...ESPECIALLY ACROSS SOUTHERN OXFORD AND FRANKLIN COUNTIES. HAVE NOT ISSUED AN ADVISORY AT THIS TIME DUE TO RELATIVELY SMALL AREA OF SUB-FREEZING TEMPERATURES AND POTENTIAL THAT MODEL GUIDANCE IS TOO LOW. NEARING SHOULD TAKE PLACE FROM NW TO SE ON SUNDAY...WITH HIGH TEMPERATURES ONCE AGAIN RISING TO WELL ABOVE NORMAL LEVELS. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... COLD AIR BEGINS POURING INTO THE AREA SUNDAY NIGHT ON A NORTH TO NORTHWEST FLOW. THE DECENT PRESSURE GRADIENT WILL KEEP WINDS UP OVERNIGHT SO ACTUAL LOW TEMPERATURES WILL NOT BE THAT COLD. BUT HIGHS ON MONDAY WILL BE 10 TO 15 DEGREES COLDER THAN SUNDAY... RANGING FROM THE UPPER 20S IN THE NORTH TO THE UPPER 30S NEAR THE COAST. MONDAY SHOULD BE THE LAST TIME PORTLAND SEES THE FREEZING MARK UNTIL SOMETIME NEXT YEAR. LARGE HIGH PRESSURE HAS ITS CENTER WELL TO THE WEST IN THE WESTERN PLAINS... THOUGH ITS INFLUENCE EXTENDS ACROSS THE CONTINENT TO THE EAST COAST. EXPECT COLD AND DRY CONDITIONS THROUGH THE WEEK. AXIS OF HIGH PRESSURE MOVES THROUGH NEW ENGLAND TUESDAY NIGHT... POSSIBLY PROVIDING AN OPPORTUNITY FOR SOME BETTER RADIATIONAL COOLING CONDITIONS BY BRINGING LIGHTER WIND SPEEDS. TEMPERATURES WEDNESDAY MORNING WILL LIKELY FALL INTO THE SINGLE DIGITS EVEN TO THE COAST... AND BELOW ZERO IN NORTHERN AREAS. LARGE UPPER TROUGH OVER CANADA HAS ITS AXIS CROSS EASTERN CANADA AND NEW ENGLAND ON THURSDAY. THIS COULD PROVIDE A FEW SNOW SHOWERS MAINLY IN NORTHERN AREAS. BUT CHANCES OF SIGNIFICANT ACCUMULATION ARE PRETTY LOW CONSIDERING HOW DRY THE AIR MASS IS AND THE LACK OF A MOISTURE STREAM INTO THE SYSTEM. THE DRY AND COLD WEATHER LIKELY EXTENDS THROUGH AT LEAST FRIDAY. MODELS THEN MOVE ANOTHER TROUGH... THIS TIME WITH MOISTURE WITH IT... THROUGH THE NORTHEASTERN UNITED STATES THIS WEEKEND... BRINGING SNOW AND/OR RAIN TO THE AREA. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... SHORT TERM...VFR CIGS THIS MORNING /MVFR IN THE MOUNTAINS/ SHOULD GIVE WAY TO VFR CONDITIONS ALL LOCATIONS TODAY. A COLD FRONT WILL APPROACH FROM THE WEST TONIGHT. THIS MAY ALLOW FOR A LITTLE LIGHT RAIN AS WELL AS MVFR CONDITIONS. VFR IS EXPECTED SUNDAY MORNING ONWARD. LONG TERM...EXPECT VFR CONDITIONS TO BE THE RULE TROUGH THE WEEK AS DRY HIGH PRESSURE REMAINS OVER THE REGION. && .MARINE... SHORT TERM...SCA FOR MOST ZONES AFTER MIDNIGHT TONIGHT THROUGH SUNDAY AS WINDS AND SEAS BUILD IN ADVANCE OF A COLD FRONT. LONG TERM...WITH BROAD HIGH PRESSURE OVER THE CENTER OF THE CONTINENT... EXPECT A GENERAL NORTHWEST FLOW OVER THE GULF OF MAINE THROUGH WEDNESDAY. A TROUGH MOVING THROUGH SOUTHERN CANADA MAY INCREASE THE PRESSURE GRADIENT ENOUGH ON THURSDAY TO PRODUCE 25 TO 35 KT GUSTS OUT OF THE WEST. THIS WOULD GENERATE HIGHER SEAS IN THE EASTERN WATERS. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...SMALL CRAFT ADVISORY FROM 3 AM TO 5 PM EST SUNDAY FOR ANZ150>152-154. && $$ NEAR TERM...KISTNER

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