Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 220230 AFDGYX Area Forecast Discussion National Weather Service Gray ME 1030 PM EDT Mon Aug 21 2017 .SYNOPSIS... High pressure will build to the south of the region through tonight before sliding to the east on Tuesday. A strong cold front will move across the region Tuesday night and early Wednesday. High pressure and drier air follows the front Wednesday night through Friday. && .NEAR TERM /THROUGH TUESDAY/...
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10pm update..forecast is on track. Skies remain mostly clear. 6pm update... just a minor update to put in the latest observations. Clear skies tonight will allow for some fog to form in valleys. At 18z...A ridge of high pressure was draped across New England. Outside of a few fair weather cumulus...GOES imagery showed fair skies across the region. For tonight...the ridge retreats offshore to our south. Outside of a few warm air advection clouds...a mainly clear night with patchy valley stratus and fog developing in the predawn hours. Lows tonight will be mainly in the 60s.
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&& .SHORT TERM /TUESDAY NIGHT/... On Tuesday...strengthening southwest flow between the offshore high and an approaching cold front will provide a hot and humid day to the forecast area. Highs will be well into the 80s with a few 90 degree readings over southeast New Hampshire into adjacent interior York county Maine. Heat indices over southeast New Hampshire should peak in the lower 90s and fall short of advisory threshold. The best forcing and wind field will be to our west although a few airmass storms may develop during the afternoon over Interior NH into the mountains of Western Maine where a few storms could produce gusty winds. The more organized convection with the front should arrive during the evening hours or after dusk across much of the area...which should mitigate the severe convective threat. Convection should end from west to east overnight as the front sweeps offshore in the predawn hours of Wednesday. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... The pattern setting up in the extended portends to rather quiet and benign weather. Front sweeps offshore Wednesday morning with any showers coming to an end early. Upper level trough will hang around Thurs and Fri with which will allow for periods of bkn clouds and some showers, mainly in the mountains, especially Friday. Otherwise cool high pressure moves in for the weekend. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... Short term /through Tuesday Night/...VFR...with sct MVFR and LCL IFR btw 08 - 12z Tue in valley fog. Late Tue and Tue night conditions lowering to MVFR with lcl IFR in developing showers and scattered thunderstorms ahead of an approaching cold front. Long Term...Any IFR should lift to VFR prior to noon Wednesday. Otherwise, VFR conditions should prevail Thu-Sat with local mvfr in lower clouds and showers, especially in the mountains possible. && .MARINE... Short Term /through Tuesday Night/...Winds and seas are expected to remain below small craft through early Tuesday as surface high pressure builds to our south. By late Tue and Tue night an increasing south to southwest flow ahead of the approaching cold front will allow SCA conditions to develop. Long Term...SCA conditions Wednesday in the wake of a cold front should wane later Wed morning with seas diminishing during the afternoon. Otherwise, tranquil conditions are expected on the waters Thu-Sat. && .TIDES/COASTAL FLOODING... We`re in the period of high astronomical tides for the month of August. The high tides of potential concern (referencing Portland Harbor where flood stage is 12.0 ft MLLW) are: 1140 PM Tonight....11.2 ft MLLW 1231 AM Wednesday. 11.1 ft MLLW The Tuesday night high tide (1231 AM Wednesday) could see some splashover as onshore flow and seas increase ahead of an approaching cold front. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory from 8 PM Tuesday to 8 AM EDT Wednesday for ANZ151-153. Small Craft Advisory from 3 PM Tuesday to 8 AM EDT Wednesday for ANZ150-152-154. && $$ SYNOPSIS...Schwibs NEAR TERM...Curtis SHORT TERM...Schwibs LONG TERM...Ekster AVIATION...Schwibs MARINE...Ekster/Schwibs TIDES/COASTAL FLOODING... is the U.S. government's official web portal to all federal, state and local government web resources and services.