Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 141701 AFDGYX Area Forecast Discussion National Weather Service Gray ME 1201 PM EST Sat Jan 14 2017 .SYNOPSIS... High pressure shifts east and weakens through today, allowing a weak cold front to move through the area early Sunday. It will not produce more than some clouds and a few flurries in the mountains. High pressure will build in behind the front Sunday afternoon through Monday. The high pressure shifts east on Tuesday and will allow a southwest flow of warmer air into the region. Weak low pressure crosses the region mid-week and will bring rain to coastal areas and mixed precipitation inland Tuesday night into Wednesday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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2102 PM UPDATE... Have updated the grids based on current conditions. Winds have subsided. Temperatures continue to struggle to climb through the teens and 20s. Have adjusted max temperatures slightly downwards for this afternoon. Winds have subsided and wind chill values are not nearly as low as earlier this morning. Otherwise, a favorable upslope wind flow will develop late tonight and Sunday morning. However, lower levels of the atmosphere remain very dry and any snow shower activity across the higher terrain should be relatively limited in scope. 730AM UPDATE... Have updated the forecast to include latest observations from early this morning which should capture most of the morning low temperatures. Light winds over the last couple of hours allowed a steep drop off at several locations, but we will see temperatures warm into the teens and 20s today. ORIGINAL DISCUSSION... Cold high pressure moves over the area today. This will bring very light winds and a mostly clear sky, although temperatures will only warm into the teens and 20s.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/... High pressure begins to shift offshore tonight, with a shortwave trough in Canada sending a weak front toward the area. Given the very dry air ahead of this front, do not expect much to occur as it arrives other than maybe some upslope clouds in the mountains. Maybe a flurry is possible as well. Meanwhile, the coastal plain should stay mostly clear, aside from some early evening high clouds associated with weak low pressure passing well south of New England. With a good period of clear, calm conditions south of the mountains, we will likely see some good radiational cooling in these spots. Have lowered temperatures a few degrees from guidance in this area, while keeping things a touch warmer in the mountains where clouds may prevent good cooling. Will see a little more wind on Sunday as high pressure to our west builds into our area. Temperatures will be a couple of degrees warmer than on Saturday, generally in the 20s to low 30s. && .LONG TERM /MONDAY THROUGH FRIDAY/... Chance of high impact weather: Low. A mix of snow and freezing rain could cause some travel problems inland Tuesday night into Wednesday morning. Models continue to show split flow at 500 mb near the west coast at the start of the extended, which will allow Pacific air to dominate the weather across the lower 48 and southern Canada, which will mean mostly above normal temps right through the week. This does not mean we will not some see some wintry precip, as a several weak 500 mb waves move through during the middle of the week. The trend toward the end of the week and thru next weekend will be to more amplified flow with a higher wave number, and potential blocking setting up over the central CONUS. Sunday night will be dry, and should be fairly cold as well. Weak 500 mb troughing could prevent full radiational cooling /which is possible given surface high centered over forecast area/, as it spreads cirrus shield across northern and eastern zones overnight, but lows range in the single digits above and below zero. Monday will see surface high shift slowly east, with westerly 850 mb flow bringing some warmer air aloft. Light winds through most of the day will prevent full mixing, but highs should push up into the mid 20s N to mid 30s S with partly to mostly sunny skies. Monday will not be as cold as previous nights, with cirrus moving in late and increasing SW flow. Lows will range form 10-15 in the N to the lows 20s in the S. The next system could bring precip into southern and western zones Tuesday afternoon, as clouds increase and S flow picks up as well. Should warm coastal areas and southern NH into the upper 30s to low 40s, but inland areas may be limited to 30-35 for their highs. Best chance for precip will be Tuesday night into Wednesday with this system. P-type forecast is tricky at this point, as split flow is generating wavy pattern across the CONUS. May see 2 separate waves move through, at least according to 00Z Euro, which holds onto stronger and more persistent surface high lingering over the maritimes through Wednesday. This would mean cold air damming and better likelihood of frozen or freezing precip inland. GFS organizes system into one trough and pushes the high out faster. Either way, some SN or FZRA can be expected Tuesday night inland, and may linger into Wednesday morning in northern ME zones. Precip should change to rain everywhere by Wednesday afternoon, and may bring some slightly colder air into the mountains on Thursday. But overall there`s not a lot of cold air behind this mid-week system, and temps should run above normal into next weekend, even if there is low confidence regarding precip timing late in the week and into next weekend. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... Short Term...Light winds and clear sky expected today through Sunday. The only exception could be a period of MVFR ceilings north of the mountains late tonight. Long Term...VFR through early Tuesday afternoon. MVFR to IFR late Tuesday and Tuesday evening with IFR expected late Tuesday night and Wednesday. RA on the coast and in southern NH and SN/FZRA Tuesday night inland going over to RA Wednesday. Could see lingering MVFR conditions through Wednesday night. && .MARINE... Short Term...Should see a brief period of light winds over the waters today as high pressure moves in. Another high moves in from the west on Sunday and could bring a bit stronger northwest winds early on Sunday, possibly reaching advisory levels again. Long Term...Winds seas remain below SCA levels Sunday night trough Tuesday but could approach SCA briefly on Wednesday. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR TERM...Cannon SHORT TERM...Cannon LONG TERM...Schwibs is the U.S. government's official web portal to all federal, state and local government web resources and services.