Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 080316 AFDGYX Area Forecast Discussion National Weather Service Gray ME 1116 PM EDT Fri May 7 2021 .SYNOPSIS... Low pressure will pass south and east of New England over the weekend, but otherwise high pressure nearby will keep conditions fairly quiet. Another area low pressure will pass to our south on Monday with widespread rain chances. An upper level low pressure system will pass over the region Tuesday with high pressure building in its wake Wednesday and Thursday. && .NEAR TERM /TONIGHT/...
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1115 PM Update...Just a few more tweaks to temperature and wind for the evening and overnight according to latest clouds. Mid and high clouds are streaming in from the south which should stunt cooling to a degree for the southern half of the area. 710 PM Update...Added a chance for some sprinkles over the Monadnock region for this evening with weak echos falling into a moderately dry airmass below. Also adjusted temperatures through the overnight period... the thing to watch for will be how quickly clouds thicken as they overspread the area right now. Already seeing scattered clouds at 7-8 kft which should offset some of the radiational cooling, especially south and east... so have raised lows by a touch for tonight. 450 PM Update...Made some changes to temperatures and skies through the evening to better fit observed trends. We`ve reached daytime maxes for the most part over the interior under stratocu and cu... temperatures are gradually falling through the 50s along the coast and inland by about a county thanks to the sea breeze, but under clearing skies. Overall a pleasant evening on tap. Previously... High pressure is centered over Maine this afternoon. Satellite imagery and surface observations both support a very dry airmass in place across Maine with dewpoints into the 20s. Further west, across New Hampshire some moisture in the form of mid- level cumulus deck and surface dewpoints in the 30s. Along the coast a robust seabreeze has developed and pushed inland as far as Strafford and interior York county. The seabreeze front is clearly visible with the suppression of the cumulus field along the seacoast. Overnight temperatures will drop rapidly after sunset. The current cloud field, indicative of the moisture profiles, will be the dividing line for temperatures as well with the western part of the area staying slightly warmer. Across the midcoast with the clear skies and very dry air, expect temps to drop to near freezing all the way to the coast. The growing season has started for the coastal zones and so have issued a Frost advisory for the midcoast, with the more inland portions of the area (inland of Rt 1) most likely to see frost. Cloud cover will move in later in the evening, however don`t expect is soon enough to keep temps up for the midcoast. Further south, for Portland and into NH expect those clouds to largely prevent a frost and so have opted for no advisory in these zones. That said, sheltered locations particularly in eastern Cumberland county should be alert to the possibility.
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&& .SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/... Saturday will start off with some clouds across the western Portion of the area. Expect a cumulus deck similar to today to slide further east as the high moves towards the Maritimes. For the afternoon some showers as possible across western NH as an inverted trough extending from a coastal low passing to our south tries to push additional moisture an instability into the area. Have kept PoPs limited as this feature is largely to our south. General pattern remains weak enough for another robust seabreeze, this one extending up through the midcoast and temperatures across the region will hold in the upper 50s under partly cloudy skies. That cloud cover will translate to warmer temperatures than tonight on Saturday keep the threat of frost at bay. && .LONG TERM /SUNDAY THROUGH FRIDAY/... The long term period will start out with fair weather on Sunday with temperatures rising well into the 60s. The only caveat will be remaining moisture that may result in variably cloudy conditions, especially in the mountains where even a couple of showers will be possible. Overall, a nice day. A short wave trough and attendant SFC low pressure center will approach Sunday night with the low center passing just to the south of the forecast area Monday morning. This will represent the best chance for a widespread wetting rain during the upcoming week. There are differences in the 12z guidance suite today as to how far north the precipitation shield will reach. Some members keep northern zones dry. However, the consensus is that most zones get measurable rain, with the best chances (cat PoPs) across southern NH and southern ME. At this time, timing of steadiest precipitation is pretty well agreed upon by a good portion of the 12z suite, which is Monday morning. A lessening of PoPs is forecast for Monday afternoon. Thereafter, upper level low pressure moves overhead for Tuesday into Wednesday with continued cool and potentially showery weather at times. Warmer and dry weather expected Thursday with the likelihood of short wave ridging moving overhead. Thereafter, rain chances look to increase on Friday. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... Short Term...VFR day as high pressure builds overhead with Fair weather cumulus across NH. Robust seabreeze has brought coastal terminals to gust up to 15kts, but that will diminish after sunset as winds calm. Similar pattern tomorrow with increasing clouds to the west, but holding VFR and a seabreeze along the coast. Long Term...VFR conditions on Sunday. Widespread rain likely later Sunday night and Monday with associated MVFR to IFR restrictions. Conditions improve to VFR Tuesday night, although occasional MVFR conditions may return on Wednesday, especially in the mountains. SFC wind gusts 20 to 25 kt are expected on Tuesday and Wednesday. && .MARINE... Short Term...High pressure remains in control of the Gulf of Maine with calm winds and seas holding through the first part of the weekend. Long Term...Relatively tranquil conditions expected Sunday and Monday before seas increase, possibly to 5 feet Monday night. Westerly winds may gust around 25 kt Tue and Wed in the developing cold air advection regime. && .GYX WATCHES/WARNINGS/ADVISORIES...
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ME...Frost Advisory until 8 AM EDT Saturday for MEZ025>028. NH...None. MARINE...None.
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&& $$ NEAR TERM...Casey/Curtis SHORT TERM...Curtis LONG TERM...Ekster

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