Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 190423 AAA AFDGYX Area Forecast Discussion...UPDATED National Weather Service Gray ME 1223 AM EDT Sat Aug 19 2017 .SYNOPSIS... A warm front will gradually push east of the region tonight. A slow moving cold front will cross the region Saturday. High pressure will build in from the west Sunday through Monday and will slide offshore on Tuesday. A cold front will move in from the west Tuesday night and will cross the region on Wednesday. High pressure will build in behind the front Wednesday night through Friday. && .NEAR TERM /UNTIL 6 AM THIS MORNING/...
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1219 AM Update... Updated near term temperatures and dewpoints which have fallen in developing northwesterly flow behind weak wave of low pressure that has formed along northward lifting warm front. Most of the rain activity has...or is just about to exit...with a few more showers over western New England closer to the mid level support. These will make a run at my western zones overnight with ample moisture still available ahead of the cold front. No other changes needed at this time. Update... Have updated the grids based on current conditions and latest set of mesoscale models. Bands of heavy rain will continue to exit through eastern sections tonight, bringing rainfall totals into the 2 to 3 inch range along a few communities near and at the coastline. Highest totals so far today have been in coastal York and Cumberland Counties. Radar rainfall estimates continue to remain underdone for this area. Low level inflow along and near the coastal front remains impressive this evening with 20 to 30 kt SSE winds coming in off the Gulf of Maine. This will continue to increase precipitation rates over the Midcoast region in a dynamic and high PW environment. Areas flood advisories have expired over southern New Hampshire and southwest Maine where, earlier, the greatest threat continued to be for urban type flooding on roadways, culverts and low lying areas. Made some minor modifications to the dew point, wind and sky cover grids for this evening. The rest of the forecast will remain relatively unchanged. Prev Disc... Warm front to the southwest continues to produce rain and rain showers mainly across southern zones. Rain will be occasionally heavy through the early evening hours as low level jet combines with PWAT`s of 2 inches or better sweeping through southern and coastal zones. Expect storm totals of 1 to 1.5 inches in southern New Hampshire and Coastal locations with locally 2 inch amounts in midcoast Maine. Rain will begin to taper off in these areas by mid evening and should clear most of the forecast area by midnight. Ocean stratus and areas of fog will blanket the region during the overnight. Lows will range from the mid 50s north to the mid 60s south.
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&& .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SUNDAY/... Warm front will be quickly followed by a slow moving cold front on Saturday. As boundary layer winds turn into the west ocean stratus will gradually get shunted eastward during the morning hours although mid coast Maine may take much of the afternoon to break out. Marginal instability associated with the front will likely kick off afternoon showers and thunderstorms mainly across New Hampshire and western Maine where heating will be the greatest. Will be a fair amount of shear so some stronger cells may produce some wind damage but CAPES may be a limiting factor. Highs Saturday will range from the 70s in central Maine to the 80s in western Maine and New Hampshire. High pressure will build in behind the front Saturday night bringing clearing skies downwind of the mountains. In the north upslope flow and lingering moisture will result in mostly cloudy skies and possibly a stray shower. Lows will range from the upper 50s north to the mid 60s south. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Skies will become partly cloudy during the day Sunday as drier air moves into the region behind the front. There could be a lingering shower in the mountains early...otherwise, temps will warm to the mid 70s north to the mid 80s south as a ridge of high pressure builds into the area. The ridge will move offshore Monday and Tuesday as a cold front slowly approaches from the west. This will lead to increasing temperatures and humidity for Monday and Tuesday. High temps Tuesday will mainly range from near 80 in the mountains to near 90 in southeastern New Hampshire and extreme southwestern Maine. Along with the warmer temps and higher humidity, the threat of showers and possible thunderstorms will be on the increase Tuesday afternoon through Wednesday as a cold front approaches and crosses the region. Showers could linger Wednesday night. Cooler and drier air following the front for Thursday and Friday as surface high pressure builds into the region. With the colder air moving in aloft and an upper level trough developing over the area Thursday and Friday, an afternoon shower can`t be ruled out, especially in mountain areas, but most areas should be dry. && .AVIATION /04Z SATURDAY THROUGH WEDNESDAY/... Short Term...IFR/LIFR ceilings and vsby overnight. Gradually improving to VFR Saturday. VFR Saturday night with areas of IFR/LIFR in valley fog. Long Term...Mainly VFR conditions for Sunday into Tuesday with IFR conditions possible in valley fog early in the mornings. MVFR to IFR conditions likely Tuesday night and Wednesday in showers and possible thunderstorms. && .MARINE... Short Term...Continuing SCA`s for tonight through Saturday. Long Term...Winds should be diminishing and seas subsiding Sunday and Monday and will be below SCA criteria through Tuesday. Winds and seas will be increasing late Tuesday with SCA conditions possible Tuesday night and Wednesday. && .GYX WATCHES/WARNINGS/ADVISORIES...
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ME...None. NH...None. MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ150- 152-154.
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&& $$ NEAR TERM UPDATE...Arnott

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