Area Forecast Discussion
Issued by NWS Portland, ME

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KGYX 280855 AFDGYX Area Forecast Discussion National Weather Service Gray ME 355 AM EST Mon Nov 28 2016 .SYNOPSIS...
-- Changed Discussion --
High pressure crosses the region to bring a seasonably cool and mainly sunny day. A warm front will cross the region Tuesday and Tuesday night, and bring some wintry precipitation changing to rain. This will be quickly followed by another low tracking out of the mid Atlantic region into New England Wednesday and Thursday, bring rain which changes to snow in the north. Another weak low passes north of the area on Thursday, with high pressure building in by the weekend.
-- End Changed Discussion --
&& .NEAR TERM /TODAY/...
-- Changed Discussion --
Still seeing some lingering cloud cover in the mountains early this morning, but otherwise clouds have dissipated downwind across the coastal plain. As high pressure crosses the area today, expect even the clouds in the mountains to eventually dissipate, though perhaps not as fast as most model guidance is suggesting. The temperature will only warm into the low to mid 40s for most areas, while northern areas may stay in the 30s.
-- End Changed Discussion --
&& .SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
-- Changed Discussion --
High pressure moves across the area tonight allowing for good radiational cooling conditions at least for part of the night. Clouds will begin arriving in New Hampshire after midnight, shutting off the cooling and perhaps allowing temperatures to begin a slow rise. Further east in Maine there will be a longer period of clear sky to allow for better cooling. Should see widespread 20s for lows, but some of the typical cold spots could drop into the teens. The first in a series of shortwave troughs will move toward the area on Tuesday, spreading warm advection clouds and precipitation into the area from west to east as the day goes on. In the low levels, an easterly flow will develop to the north of a developing surface low over southern New England. This will cause cold air to pile up against the terrain, holding temperatures down across interior western Maine and perhaps into eastern New Hampshire for much of the day on Tuesday while southern and coastal areas rise into the 40s. This could play havoc on precipitation type. It seems likely that any initial snowfall will be light before warm advection aloft changes it over to rain for the southern two thirds of the forecast area. But temperatures at ground level could still be at or below freezing, meaning that there will be the threat for freezing rain. In southern New Hampshire, there will be a chance of freezing rain Tuesday morning before temperatures warm. Any ice accumulation should be quite light, but could be just enough to cause slick driving for the morning commute. Further to the northeast in interior western Maine cold air will hold on longer due to the cold air damming effects, allowing for the threat of freezing rain to last into the afternoon. Here ice accumulation could approach or exceed one tenth of an inch before the temperature eventually warms above freezing. Further north in far northern parts of the forecast area especially central Somerset County, temperatures at all levels may stay cold enough for snow through most of this event, leading to snow accumulations of 3 to 6 inches. Precipitation will come to an end from west to east Tuesday night, with temperatures fairly mild in the wake of the low as the cold air damming breaks. After coordinating with neighboring forecast offices to the east and south, we have decided to hold off on issuing any winter weather advisories at this time. For now we will focus efforts on refining the forecast and getting the word out through the hazardous weather outlook, social media, and briefing tools. Subsequent forecast shifts may have higher confidence in precipitation type to issue the appropriate advisories.
-- End Changed Discussion --
&& .LONG TERM /WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
Chance of High Impact Weather: Low. Some accumulating snow will be possible in the mountains Wednesday night into Thursday. At 500 mb, Rex blocking upstream and downstream will gradually break down over the long range, and this will allow for unsettled and changeable conditions Wednesday into the weekend, with small scale waves moving through. Normal 850mb temps run -5C and slightly above, and we look to stay near or above this through the weekend. We`ll start off Wednesday with very weak ridge in place, but this quickly exits east as 500 mb trough deepens to our west and warm advection precipitation starts to move in from the SW in the afternoon. This will start as rain everywhere, with warm air in place at the surface and aloft. As a weak wave rotates NE around the 500mb closed low to the west, will see surface low develop to our south and track across the Gulf of Maine Wednesday night into Thursday. This will allow for precipitation to continue thru Wednesday night, and possibly into Thursday morning. It will also begin to pull some cold air in from the NE and rain will go over to snow in the far NE zones, as well the higher terrain to the S and W including the Whites and the Mahoosucs. These areas could see several inches. Otherwise precipitation winds down Thursday. Colder air does move in behind the system, but as often happens, will have to wait for upper level trough to pass thru for the coldest surge of air, which will come in as a weak surface low passes to our N on Friday, which could produce some snow showers in the mountains. The weekend looks colder /but generally near normal/ and dry, with the next system approaching Sunday night or Monday.
-- End Changed Discussion --
&& .AVIATION /08Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
Short Term...VFR conditions expected today and tonight, but expect increasing clouds and lowering ceilings from west to east during the day Tuesday. In southern New Hampshire and coastal Maine expect mostly rain, with a chance of freezing rain in the early morning Tuesday. In interior western Maine, there will be a threat of freezing rain extending into Tuesday afternoon before eventually changing to all rain. Weather observations for Rockland are note available and the FAA is working to resolve the issue. Until these become available again, the Rockland TAF will be issued based on best estimate conditions with no amendments scheduled. Long Term...A period of IFR or lower is expected centered around Wednesday night in rain, low ceilings and possibly fog. Some improvements expected outside of the mountains by Thursday afternoon, with VFR likely on Friday.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
Short Term...High pressure moving across the area today and tonight will allow a brief period of calm winds and low seas. Low pressure tracking through the Gulf of Maine on Tuesday could bring advisory level wind speeds ahead of it. Long Term...Will likely see a period of low level SCA winds/seas Wednesday night, but it may be brief as surface low tracks right along the coast. Also, could see borderline SCA winds in the NW flow behind the system Thursday.
-- End Changed Discussion --
&& .GYX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
ME...None. NH...None. MARINE...None.
-- End Changed Discussion --
&& $$ NEAR TERM...Kimble SHORT TERM...Kimble LONG TERM...Cempa

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.