Area Forecast Discussion
Issued by NWS Portland, ME

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971 FXUS61 KGYX 120653 AFDGYX Area Forecast Discussion National Weather Service Gray ME 253 AM EDT Wed Jun 12 2024 .SYNOPSIS...
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Scattered showers and thunderstorms develop today as an upper level low continues to slowly move through, with the most widespread shower activity expected across the higher terrain. Temperatures moderate on Thursday ahead of an approaching cold front. The front crosses New England on Friday, with high pressure building in behind the front for the weekend. The high moves offshore early next week, setting up a moderating trend with warm temps likely next week.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Plenty of cloud cover remains in place, mainly over northern and western portions of the forecast area this morning along with patchy fog. A few showers per current radar trends will continue in this region as well. The latest HREF solution once again has this cloud cover expanding over southern portions of the forecast area with onshore winds allowing for the most stabilization along the coastline. Afternoon heating will combine with a departing upper level low pressure system to trigger some scattered showers across the region this afternoon, especially the higher terrain. Some limited instability will allow for a thunderstorm or two mainly away from the coastline in slow moving precipitation embedded in the weak flow. This is in good agreement with the latest SPC thunderstorm outlook. Afternoon highs will mainly be in the 70s, but cooler temperatures in the 60s will continue for the Midcoast region where winds will be onshore.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
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Any leftover showers after sunset and increased stabilization will gradually diminish tonight. In it`s wake, sufficient low level moisture and a limited flow over the region will once again allow for patchy fog. The HREF continues to suggest maritime fog off the Gulf of Maine may attempt to move into the coastline region. Heights rises will finally arrive on Thursday as the stubborn upper level low pressure system shifts east and weakens over the Canadian Maritimes. This will allow for mainly dry conditions. Warm air advection will allow for H8 temperatures to reach +14C by late in the day. Sunshine and mixing will allow for afternoon highs to reach the 75 to 85 degree range.
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&& .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
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Overview... A cold front passes through to close out the week, with high pressure bringing dry and seasonable conditions for the weekend. The high moves offshore next week, setting up an extended warming trend with a ridge building across the eastern US. Details... Any showers or thunderstorms are expected to hold off until after dark Thursday evening as a cold front approaches from the northwest. Weakening showers and a few thunderstorms reach into northern areas during the overnight hours as the front approaches. The front then crosses during the daytime on Friday. Showers are still likely across northern areas early on Friday, but the better chance for thunderstorms looks to be across southern areas where more daytime heating can occur before the front`s arrival. Some strong storms will be possible with the front as dew points climb into the 60s during the day on Friday, but the timing of the front will be important to see if we end up with anything more widespread or severe. A delayed frontal passage of only a couple hours increases this threat, so we`ll be monitoring it over the next couple of days. The front clears the coast Friday night, with high pressure building in from the northwest for the weekend. The high brings much drier air and mainly sunny conditions. Temps look seasonable on Saturday, with northwesterly downslope flow allowing the coast to warm to near 80, while the mountains stay mainly in the mid to upper 60s. Saturday night looks crisp in most spots, with lows mainly in the 40s and dry conditions. Temps begin to moderate on Sunday as the high moves overhead, with highs mainly ranging from the mid 70s to low 80s. A seabreeze develops during the afternoon along the coast as the high moves offshore, knocking back temps along the coast in the afternoon. The high moves offshore and begins to strengthen through midweek, likely centered between Nova Scotia and Bermuda. This is the sign at the surface of a building ridge across the Northeast and Great Lakes next week, helping to bring some potentially significant heat to New England next week. Temperatures steadily moderate early next week, with highs into the 80s for most areas in increasing southwesterly flow, except for the MidCoast which holds in the 70s. Temps likely then warm to near 90 in a lot of spots by Tuesday. Afterwards, the heat looks poised to continue to build through midweek as the ridge builds. As with the prospect of any period of heat in New England from this far out, there are still of lot of different factors that can serve as spoilers that we need to remain mindful of. There will likely be leftover MCSs transiting the ridge from the Plains, and uncertainty on whether these will move through New England or north of the area. There are prospects of a cut off low developing south of Atlantic Canada, with the chance of this delivering a back door front with easterly flow by late next week. So while all signs are pointing towards heat at this point, there are still other factors we need to remain mindful of as the possible peak of the heat remains over a week away.
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&& .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
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Short Term...A few scattered showers and an isolated thunderstorm can be expected this afternoon with a brief period of MVFR or even IFR conditions. This will mainly be away from the coast. Patchy fog may develop again tonight with IFR conditions in some of the interior valleys. Fog may also develop along portions of the coastline. Thursday will be mainly dry after some early morning fog and IFR/LIFR conditions. The fog may linger across portions of the coastline. Long Term...Some showers and storms bring brief restrictions to most terminals Friday afternoon. VFR then prevails from Friday night through early next week.
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&& .MARINE...
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Short Term...Below SCA conditions with waves 2 to 3 ft and a general southerly gradient across the waters. Marine fog development will be likely over the next 24 to 36 hours as humid conditions arrive. Long Term...SCA conditions are possible Thursday night and Friday ahead of a cold front. The front crosses the waters Friday night. Fair conditions are then expected for the weekend and early next week as high pressure settles along the Eastern Seaboard.
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&& .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ Cannon