Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 211611 AFDGYX Area Forecast Discussion National Weather Service Gray ME 1211 PM EDT Fri Apr 21 2017 .SYNOPSIS... Low pressure will move slowly east into New England today. The approaching low and a cool onshore flow will provide rain to the region through tonight with some wet snow and sleet possible across the higher terrain near the international border. This slow moving system will keep cool unsettled conditions across the area for Saturday. A cold front will cross the region Sunday. A ridge of high pressure will gradually build in from the west for Sunday into early next week. Low pressure will move up the Eastern Seaboard Tuesday and Wednesday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1205 PM...Current forecast package is on track with only minor updates to reflect the current mesonet in near term grids. Prev Disc... 950 AM...Minor ESTF update to reflect the current mesonet and radar trends in near term grids. Prev disc... 6am update...Rain has moved into Maine now but is already pulling out of the CT river valley. Have lowered pops a bit on the VT border but added Fog as most airports are reporting some fog. prev disc...Rain is very slowly making its way into western New Hampshire this morning in association with a warm front ahead of a low pressure center over Lake Ontario. The steady rain will move through fairly quickly in the morning hours but drizzle low clouds and patchy fog will linger through the afternoon and into the evening. Overall this system has been slow to advance and have decreased the PoP for eastern portions of the area. Have also gone to more of a widespread drizzle for this afternoon as most guidance hints and the system falling apart as it finally arrives this morning leaving us with a generally damp day. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... The low pressure will move through the St. Lawrence valley overnight pushing a cold front through northern New England. This will spark another round of steadier showers through the first half of tonight. By Saturday Maine and New Hampshire end up stuck between dueling low centers, one to our north near Quebec City and one to our south just east of the 40N/70W benchmark. This leaves us in cool damp weather. For the coast easterly on shore flow will keep temperatures in the 40s with fog through the day. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... Low pressure will gradually pull east of the region and through the Canadian Maritimes by Saturday night. This will allow for a small and relatively weak area of high pressure to build into the region on Sunday. A cold front will begin to drop through the region Sunday night, weakening as it does so. This system will be relatively moisture starved to any chance for precipitation will be limited to the northern mountains. By Monday, the remains of the front will begin to retreat northward as a warm front. Conditions will remain dry however, with some sunshine, especially over southern areas of Maine and New Hampshire. This sunshine will be short lived however as a cutoff low pressure system over the southeastern United States begins to lift northward beginning Tuesday. The models have been fluctuating on the track and timing of this system as the energy from this system is just reaching the Pacific northwest this morning. With the 00Z model suite, The Euro was the weakest with this system. In any case, some cloud cover is expected to advance north and precipitation to enter southern areas by Tuesday morning. As the upper level support weakens, the system will shear out to the northeast, allowing for rain to continue across the region on Wednesday. If followup model runs indicate that this system will remain more intact and robust, tides will need to be monitored during the midweek period next week. This will be a period of very high astronomical tides. && .AVIATION /16Z FRIDAY THROUGH TUESDAY/... Short Term... IFR conditions have already developed along the coast as onshore flow in advance of the approaching low. IFR to LIFR will continue through the day today and into Saturday along the coast. In the interior a slight improvement with widespread MVFR currently. Brief periods of IFR are possible in the interior especially this morning as the heavier rain moves in but overall expect to see consistent MVFR with occasional drops to IFR in FG throughout the region until Saturday. Long Term...Some improvement in ceilings and visibilities expected Saturday evening. Conditions will then improve to MVFR region wide for Sunday. VFR seems to be the most likely scenario Monday with deteriorating conditions once again for Tuesday into Wednesday. && .MARINE... Short Term...Easterly winds will continue through today with building seas. SCA remains in effect for tonight into Saturday. Long Term...SCA will likely be needed into Saturday night, mainly for seas on the outer waters. More tranquil conditions are expected Sunday into early next week. && .FIRE WEATHER... && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until 7 AM EDT Saturday for ANZ150>154. && $$ ES is the U.S. government's official web portal to all federal, state and local government web resources and services.