Area Forecast Discussion
Issued by NWS Portland, ME

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798 FXUS61 KGYX 281931 AFDGYX Area Forecast Discussion National Weather Service Gray ME 331 PM EDT SAT MAY 28 2016 .SYNOPSIS...
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A cold front will push westward across Maine and New Hampshire tonight as high pressure builds into New Brunswick and Nova Scotia. An easterly onshore wind will bring much cooler temperatures on Sunday, although to the west of the mountains it will be hot and humid again. Warm, moist air moves into the area again on Monday with showers and thunderstorms expected. A cold front moves through from the northwest late Tuesday with high pressure building behind it through late week.
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&& .NEAR TERM /TONIGHT/...
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Any afternoon showers and thunderstorms that develop will diminish this evening. Winds will shift to the east northeast as high pressure moves into New Brunswick and Nova Scotia and a back door cold front moves westward across the region. This will bring a cool, maritime air mass into the low levels this evening. Water temperatures are in the low to mid 50s and air temperatures within this air mass will not be much warmer than that. Should see some low level cloudiness develop as that cold air wedges itself in below the warm/moist air above it. By morning there could be some fog and drizzle as well, especially over southwest Maine and eastern New Hampshire.
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&& .SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
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Onshore easterly flow will keep cool air wedged in at the surface across Maine and eastern New Hampshire on Sunday. Near the coast temperatures may not get out of the upper 50s to low 60s, while inland areas could rise a little warmer. This cold air will not make it all the way across the mountains, though, so western New Hampshire will see another hot and humid day with temperatures in the 80s. Afternoon showers and storms are more likely to pop up across New York, Vermont, and western Massachusetts but there could be a stay shower or storm move through western New Hampshire. Remnant showers and thunderstorms associated with a shortwave trough moving through the eastern Great Lakes will eventually make their way into New Hampshire and western Maine Sunday night. This activity should be diminishing as it moves through.
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&& .LONG TERM /MONDAY THROUGH SATURDAY/...
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High impact wx: there is a small chance that heavy downpourslate Sunday night into Monday morning could produce localized flooding. The hemispheric 500 mb pattern will continue to feature a western Atlantic ridge, although it will not reach as far poleward as it is this weekend. After one short wave moves through Monday, will see a few more during the course of the week, but none of them are strong enough to break down the ridging, but just temporarily dampen it. Overall, 850 mb temps through the period will be above normal, but bouts of onshore flow will help keep sfc temps in the normal to above range, and not expecting anything quite as warm as this weekend. Monday starts off fairly murky and rainy, with fog and shra like in the morning, as marine layer undercuts the warm air loft. Also as weak 500 mb trough approaches from the west will see showers out ahead of the front, with some tropical moisture from TD 2 being drawn northward. Could see a few heavier showers and some thunderstorms, especially Monday morning. Also RH will be on the rise during the day as well. May see some brief clearing late in the warm sector, but a frontal boundary will approach from the west and could spark off a few sct thunderstorms...especially in the mountains late. Despite a fair amount of clouds highs Monday will manage to get into the mid to upper 70s in inland areas, and to around 70 on the coast. The front moves thru Mon night and skies will clear but air mass not much different behind it and will have to wait for second 500mb wave to pull another cold front thru late Tuesday, but without much in the way of showers, which would be limited to the mountains. Highs Tuesday will generally be in the low to mid 80s inland, and mid-upper 70s on the coast. Sfc high then builds in from north Wed beneath decent ridging aloft on Wed, and then shifts off to the northeast on Thu. Both days look fair although Wed will be warmer as flow will be from the west with highs in the mid 70s to low 80s. The onshore flow will keep the coast close to 70 on Thu, but will warm into the mid 70s inland. Next chc of rain will be Fri or Saturday as cold front approaches from the west. GFS/Euro seem to be struggling with TD 2 during the mid-late week as they keep it lingering near the Carolinas until late week, and then start to move it E-NE. This could affect the timing of our rain chances late in the week into next weekend.
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&& .AVIATION /19Z SATURDAY THROUGH THURSDAY/...
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Short Term...VFR conditions to start off the night, but an onshore flow should lead to low clouds developing again tonight along the coast. Expect IFR conditions from Portsmouth to Rockland, but VFR should continue for western New Hampshire except for a brief period of possible valley fog at Lebanon. Low clouds will likely linger through much of the day Sunday along the coast while western New Hampshire will be VFR with an outside chance of a shower or thunderstorm in the evening. Long Term...IFR or lower Monday morning will improve to VFR from SW to NE Monday afternoon. After which, VFR is expected through Thursday.
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&& .MARINE...
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Short Term...Easterly flow develops over the waters tonight behind a back door front. Winds should remain below advisory levels. Wave heights will be building in the western Gulf of Maine on that easterly fetch, but at this time are forecast to stay below 5 feet. Long Term...Monday will see a surge in SW flow ahead of a cold front, and may need SCA Monday afternoon into Monday night. Otherwise, the rest of the week should remain blow SCA levels.
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&& .FIRE WEATHER...
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Expect cool and moist onshore flow Sunday. It will warm up Monday and Tuesday but will still be fairly moist. Although showers and thunderstorms are possible several days during the coming week, widespread significant rainfall is not expected.
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&& .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ LONG TERM...Cempa

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