Area Forecast Discussion
Issued by NWS Portland, ME

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636 FXUS61 KGYX 221854 AFDGYX Area Forecast Discussion National Weather Service Gray ME 254 PM EDT Sun Apr 22 2018 .SYNOPSIS...
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High pressure centered over the eastern Great Lakes will build farther into the area tonight. The high pressure center crests over the area Monday before shifting offshore by Tuesday. Fair weather and seasonable temperatures are forecast during this time. By mid week, unsettled weather returns with the approach of our next storm system. Beyond that, another fast moving system may be in the cards for the end of the week.
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&& .NEAR TERM /THROUGH TONIGHT/...
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Beautiful day in progress with a few clouds on this Spring day. Sunny skies and low dew points have allowed temperatures to climb into the mid to upper 50s for much of the region. The highest temperature at 2 PM was 59 at both Concord and Nashua. Building high pressure from the west will allow winds to drop to calm. Low PW values (0.22" this morning and dropping) will support near ideal cooling conditions for this time of year. Expecting temperatures to fall into the lower 20s to low 30s across the region with coldest readings north.
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&& .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
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After a chilly start on Monday...temperatures will rapidly increase in a very dry airmass and full Spring sunshine. Monday looks pleasant with light winds, very few clouds, and temperatures topping out in the mid 50s north to lower 60s under the strong late April sunshine. A few readings closer to 65 will be possible for the Concord, Nashua, Manchester corridor. The light synoptic flow will transition to a seabreeze with the mercury dropping off during the afternoon near the coast. High pressure pushes offshore overnight Monday allowing some light southerly flow to return to NH and northern Maine. We`ll see cirrus clouds begin to arrive overnight. These factors will keep overnight lows a few degrees warmer than the previous night.
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&& .LONG TERM /TUESDAY THROUGH SUNDAY/...
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A strong ridge of high pres over the area Tue moves offshore Tue night allowing a return south to southeast flow to develop. A strong upper short wave moves to the mid atlantic coast by Wed morning spawning a surface low near DELMARVA that will move northeast late Wed and Wed night. This will spread a soaking rain across the region Wed into Wed night with between .75-1.25 inches of rain with some locally higher amounts. The surface/upper trof lift northeast Thu toward the maritimes allowing instability showers to stick around due to the cold pool aloft combining with some surface heating allowing steepening lapse rates enhancing some showers. Thu night into early Fri a short wave ridge briefly brings clearing to the area. By Fri afternoon a strong long wave trof approaches the east coast brining another surge of southerly moist unstable air spreading more rain into the area by late Fri afternoon and Fri night. The system exits Saturday but leaves a colder cyclonic northwest flow in its wake...this will mean scattered mainly afternoon showers can be expected to develop once again. Temps will be briefly very mild Tue but cooler with the unsettled weather the rest of the week.
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&& .AVIATION /18Z SUNDAY THROUGH FRIDAY/...
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Short Term /through Monday/...VFR. Long Term...VFR through Tue. IFR/LIFR conditions Wed into Wed night improving to MVFR conditions in sct -shra Thu. VFR conditions Thu night into early Fri. Late Fri conditions lower to IFR in developing rain from S-N.
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&& .MARINE...
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Short Term /through Monday/...Quiet on the waters with winds and seas below SCA under a building surface high. On Monday mid day and afternoon...a developing seabreeze along the coast will bring gusts to 20 kt with briefly building seas. Long Term...No flags through early Wed. SCA conditions develop late Wed and continue through Thu over the outer waters.
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&& .FIRE WEATHER...
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Winds will be light and backing from the west to the southwest during the day on Monday. Low dew points will yield RH values in the 20 to 25% range during the afternoon hours over most of southern and central NH as well as interior Maine. A seabreeze may produce wind gusts higher than 10 mph along the coast, briefly increasing fire weather conditions in the afternoon.
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&& .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR TERM...Hanes SHORT TERM...Hanes LONG TERM...Marine

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