Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 191425 AFDGYX Area Forecast Discussion National Weather Service Gray ME 1025 AM EDT Sat May 19 2018 .SYNOPSIS... A warm front will lift north into the region today through tonight, bringing a period of rain. It will be followed by a cold front on Sunday. High pressure will build in from the west Sunday night and will pass out to sea south of New England Monday. Weak low pressure will pass south of New England on Tuesday. A cold front will drop south through the region Wednesday. Weak low pressure tracks along the international border late Thursday into Friday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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1020 AM...Based on radar composite over New England, and on latest HRRR runs, have put the the arrival of rain back by a couple of hours across most of the CWA. Tds still in the 20s in many spots and 12Z KGYX RAOB showing very dry layer of air of air between 850 and 700 mb, as well as around 500 mb, suggest it`ll take a little while for the precip to get going, and for it to reach the ground. So, arrival time will be more like early afternoon in the S and W zones, and later afternoon in the eastern areas. This will also allow for max temps to rise a bit more before the rain moves in, especially in areas where sun is hanging in there longer. 730AM UPDATE... Have updated the forecast to adjust for early morning temperatures which have risen to near or above freezing in the areas formerly in the advisory/warning. Thus this headline was allowed to expire. No other significant changes were needed to the forecast at this time. Area of rain on regional radar is timed to arrive in southwest New Hampshire right around 15Z (11AM) which is fairly well covered in current forecast. ORIGINAL DISCUSSION... Rain moves in from south to north as the day goes on, falling along and ahead of a warm front trying to make its way north. Easterly flow ahead of the front will pull in a cool, maritime air mass and keep temperatures fairly cool, dropping into the 40s. The warmest areas will be in the northeast where the clouds and onshore flow arrive later in the day. Further south, high temperatures will be in the morning before falling slightly as rain arrives.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... The warm front lifts north, and the steady rain comes to an end. However, some disorganized showers are possible behind the warm front through the night. A very moist air mass will be moving into the area, so expect a mild night. There could be some fog formation as well as these high dewpoints move in overnight. On Sunday expect a southwesterly flow to clear things out at least briefly during the day, and temperatures will warm into the 70s for most areas. A cold front moves in from the northwest during the day, with showers and even a thunderstorm possible as it moves through. The best chance of rain will be in the north with chances dropping as the front arrives on the coastal plain. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... On Monday morning the cold front will be well offshore, but NW winds will still be ushering in cooler air from Canada. Very early on some fog will be around before winds pick up. Clear skies and a dry airmass will allow temperatures to reach the mid 60s/lower 70s north to mid to upper 70s for much of NH and from the foothills of Maine south. Clouds will begin to thicken and lower Tuesday morning as a ripple of short wave energy arrives in the westerlies. Tuesday will be just a few degrees cooler than Monday however with WAA in place and a southerly fetch. Showers will spread from the west into Wednesday. A cold front will accompany a more significant short wave swinging through Quebec...saving most of the QPF for the mountains. Most other locations will see hit or miss showers. There may be a clap of thunder, but at this time instability looks too far north and too fleeting to include it in the forecast. On Wednesday temperatures will spike ahead of the front in the mid to upper 70s once again, with cooler temperatures across the north. The heat is knocked back several degrees for Thursday, but it should be mostly sunny and pleasant with widespread readings in the 60s and lower 70s. Westerly flow increases Friday ahead of the next cold frontal passage as another weak system dips out of southern Quebec and into northern NH and ME. Again this will bring rain showers to the north with higher temperatures (in the 70s) expected to the south and west. Models are in agreement as to another rainfall event next weekend- with a warm front lifting across the area Saturday night, and a cold front moving SE across New England Sunday afternoon. This would be a more widespread and heavier rainfall event than we are expecting for the work week. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... Short Term...Expect increasing clouds and lowering ceilings from southwest to northeast as the day goes on. Some steady rain should bring MVFR to IFR conditions for most of the area. May see a break in the rain overnight, but clouds continue and fog is possible. Some clearing expected Sunday, but showers will be possible as a cold front moves through during the day. Long Term...Patchy fog possible early Monday morning, otherwise expect mainly VFR Monday through Wednesday, with some possible tempo restrictions in SHRA on Tuesday...mainly for HIE and LEB. && .MARINE... Short Term...A warm front lifts north across the waters today, with a southwesterly flow developing behind it. Models are indicating this southwesterly wind could gust to about 25 KT, however, such a wind direction tends to get over-forecast by the models especially when water temperatures remain cold. Therefore have not yet issued a Small Craft Advisory due to uncertainty, but there is a chance one will be needed tonight into early Sunday. A cold front moves through Sunday evening, with a shift to northwest winds. Long Term...Winds increase across the waters Monday afternoon but should stay below SCA criteria, as will seas. A brief increase is expected Tuesday and Wednesday as a frontal system passes through the region. Again, winds should stay below criteria. && .FIRE WEATHER... After a dry start, expect increasing clouds and eventually rain to overspread the entire area today into tonight. Another round of showers are possible as a front moves through on Sunday, with dry air moving in again behind the front. && .GYX WATCHES/WARNINGS/ADVISORIES...
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ME...None. NH...None. MARINE...None.
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&& $$ SYNOPSIS... NEAR TERM...Cempa/Kimble SHORT TERM...Kimble LONG TERM...Hanes AVIATION... MARINE... FIRE WEATHER... is the U.S. government's official web portal to all federal, state and local government web resources and services.