Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 210432 AFDGYX Area Forecast Discussion National Weather Service Gray ME 1132 PM EST Mon Feb 20 2017 .SYNOPSIS... High pressure will crest over the area tonight before gradually shifting on Tuesday. A warm front approaches from the west Tuesday night and early Wednesday bringing some light precipitation to the region. Temperatures will be on the increase for the remainder of the week with a few chances for showers mainly over the mountains. A more substantial system arrives for the weekend. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
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Update... Have updated grids based on current observations and latest set of mesoscale models. Northwest winds continue to bring in cooler and drier air into Northern New England. Expect clear skies with diminishing winds and radiational cooling after midnight tonight. However, to this point late this evening, dew points have not lowered sufficiently to consider widespread below zero readings for overnight lows over the northern mountains. May be nudging a few of our normally colder locations using the PFM/Serp tool and have adjusted mins a few degrees downwards from their current forecast, especially over northern/mountain regions. Adjusted winds and current dew points. Otherwise, the rest of the forecast package will remain relatively unchanged. Prev Disc... Downsloping winds have cleared out cloud cover and allowed for another nice day despite being much cooler than we were yesterday. We are still above normal with a somewhat gusty NW flow in place. Tonight`s temperatures were a mix of short term meso guidance taking into account some weak cold air advection, clear skies, and winds going nearly calm overnight in many spots as high pressure crosses to the Atlantic. The valleys and other drainage areas will cool off quickly and we will see spots below 10 degrees in the mountains by morning. Elsewhere teens are expected.
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&& .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... High pressure will shift east on Tuesday as a warm front approaches from the west. In a very dry air mass we will have another quick warm up tomorrow with highs in the mid 30s to mid 40s...a pretty large diurnal jump with the sun angle increasing each day. After a mostly sunny start to the day high clouds will overspread the region during the afternoon. Warmer air arrives Tuesday night/Wednesday morning as temperatures drop below freezing at the surface. This weak overrunning pattern will create some areas of light wintry precipitation. The main concern will be a few hundredths of freezing rain which may fall towards morning mainly in the mountains and perhaps downstream over the coastal plain. Again this looks like a rather low impact event but may bring some impacts as far as slick driving surfaces. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... A warm zonal flow develops midweek. Models move a strong short wave through the midwest Thursday and into the Great Lakes by Saturday. In advance of this trof ridging and even warmer temps are expected for Thursday and Thursday night. By Friday a warm front will move north across the region as an increasing southerly flow develops to the east of the approaching trof. Some light precipitation is possible as this warm front moves north across the region. Friday night and Saturday will remain mild and went a little above guidance temps. The approaching upper trof will move east across southeast Canada late Saturday with a trailing cold front and associated showers that will continue into Saturday night. A return to a colder northwest flow will develop by Sunday. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... Short Term...VFR today through Tuesday with increasing cloud cover and possibly some MVFR decks very late Tuesday. Long Term...VFR conditions generally expected through the end of the week. A low pressure system cutting thru the Great Lakes will push a warm front thru the area Fri. This will likely bring an extended period of MVFR or lower. MVFR conditions in scattered showers will continue Saturday due to an approaching cold front. && .MARINE... Short Term...Winds will decrease from west to east overnight as high pressure shifts towards the coast. Have dropped SCAs. Long Term...Winds and seas expected to remain below SCA thresholds thru the end of the week. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR TERM...Cannon SHORT TERM...Cannon LONG TERM...Cannon is the U.S. government's official web portal to all federal, state and local government web resources and services.