Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 241042 AFDGYX Area Forecast Discussion National Weather Service Gray ME 642 AM EDT SUN JUL 24 2016 .SYNOPSIS... A narrow ridge of high pressure will build in from the west today and will shift offshore tonight. This will bring sunny skies, with less humid conditions today. A cold front will approach from the west on Monday and will cross the region Monday night, providing another round of showers and thunderstorms. High pressure will build in from the west Tuesday through Wednesday. A weak frontal boundary will settle south from Canada Wednesday night and will stall over the region on Thursday. High pressure building in from the north will suppress the stalled frontal boundary south of New England Thursday night. Several weak waves of low pressure will track east along the stalled frontal boundary Friday and Saturday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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640 am...Just a quick update to adjust grids based on current T/Td and sky. clouds in the mountains will diminish in the next few hours as upslope flow weakens and atmosphere mixes out. Otherwise and warm for today with lower humidity. Previously...A tranquil day is expected compared to the last two, with mainly sunny skies, lower humidity and seasonably warm temps from around 80 in the mountains to the upper 80s in southern NH. This is thanks to a ridge moving in aloft and sfc high pressure sliding in from the west beneath it. Initially NW flow aloft will provide a sfc flow W-NE...but as the gradient weakens may see a weak sea breeze develop mid-late afternoon.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... The sfc ridge move across the CWA tonight, and it is expected to remain dry. SW flow will begin to develop behind the ridge and this will allow the humidity to start creeping in late tonight. Will also see some cirrus moving overnight. Overnight lows will range from the mid-upper 50s in the the low 60s in srn NH and along the ME coast. TDs will go from tolerable Monday morning to steamy by afternoon as flow shifts around to south. Inland areas will be able to tap into 850 temps around 18-19C, but more of an onshore will be prevalent through a large part of the day...especially east of Portland. Highs will reach into the low 90s in southern NH...and mid to upper 80s most everywhere else. The coast, from Casco Bay East will generally be limited to the 70s to around 80. Equatorward end of 500 mb wave will approach from the west Monday, and will see cold front approach from the west. Will see showers and storms develop, mainly in the afternoon. Still lots of questions as to intensity of storms, but there is some potential for strong to severe storms, although extent of cloud cover, and timing of beast instability vs best shear still in question, so will hold off introducing any enhanced wording at this point. Still coverage of convection should increase from west to east as the afternoon progresses. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
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Cold front will cross the region Monday night sweeping showers and thunderstorms east of the region by midnight or shortly after. Low temperatures will range through the 60s to near 70. Drier and somewhat cooler air will ride into the region Tuesday on an increasing northwest flow ahead of high pressure building in from the west. Should see a mix of sun and clouds with highs ranging through the 80s. High pressure will continue building in from the west Tuesday night and Wednesday. Lows Tuesday night will range from the mid 50s to lower 60s north and mid to upper 60s south. Highs on Wednesday will range through the 80s to near 90. Could see a late day shower or Thunderstorm in far northern zones as a very weak frontal boundary drops into southern Quebec. Weak frontal boundary will sag south into the region Wednesday night and will stall over the area on Thursday. Expect variable cloudiness Wednesday night with just a chance of a shower. Low temps will bottom in the lower to mid 60s. Showers and thunderstorms will develop on Thursday as stalled frontal boundary remains draped across region. Very little in the way of shear is expected so looking at pulse type...very slow moving convection and with pwat`s approaching 1.5 inches could see some very heavy downpours with these storms and possible flood problems. Best chance for storms will be inland as weak gradient will allow for a strong sea breeze to develop shielding coastal areas from these storms. Highs will range through the 80s to near 90. Frontal boundary will gradually sag south of New England Thursday night as high pressure noses in from the north. Looking for variable clouds overnight with just a chance of a shower. Very broad shallow shortwave approaching from the west will keep skies fairly cloudy on Friday. Good instability in the afternoon will once again lead to showers and thunderstorms. Should see cooler temps with highs ranging from the mid 70s to mid 80s.
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&& .AVIATION /12Z SUNDAY THROUGH THURSDAY/... Short Term...Mainly VFR through Monday. Some valley fog possible this morning but boundary lyr flow is increasing thru the morning, and clouds over northern NH will limit it yo some degree at KHIE/KLEB. Also, thunderstorms possible Monday afternoon. Long Term...VFR Monday night Through Thursday. Areas of MVFR ceilings and vsby in scattered showers and thunderstorms Thursday. && .MARINE... Short Term...All quiet on the waters through Monday. Only issue will be thunderstorms late Monday afternoon. Long Term...No problems noted. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ SYNOPSIS... NEAR TERM...Cempa SHORT TERM... LONG TERM... AVIATION... MARINE... is the U.S. government's official web portal to all federal, state and local government web resources and services.