FXUS61 KGYX 032249 AFDGYX Area Forecast Discussion National Weather Service Gray ME 649 PM EDT Tue Aug 3 2021 .SYNOPSIS... High pressure will allow for dry conditions through Wednesday, although a stationary front will linger offshore bringing clouds into portions of the region. Low pressure will track through southern New England Wednesday night before passing through southern Maine Thursday morning. An upper level trough will bring more clouds to the region Friday. More scattered showers will cross New England over the weekend as yet another trough crosses the region. && .NEAR TERM /THROUGH WEDNESDAY/... 645 PM...Quick update to adjust temps/sky based on current obs. Cirrus this evening will be patchy but on the denser side, and will like become thicker after midnight, which will limit temps from falling too much after midnight in the souther half of the CWA so lows will generally range from the mid 50s to around 60 here, while in the N, with less clouds looks for low 50-55. Previously...Several disturbances will move along a stalled out frontal boundary off the Eastern Seaboard beginning tonight. As one of these weak system passes well east of the Gulf of Maine, clouds will continue to spill into southern portions of the region tonight. This will allow for warmer readings along the south with lows in the upper 50s to lower 60s. Further to the north, mainly clear skies will allow for patchy late night fog, with some of it being dense. && .SHORT TERM /WEDNESDAY NIGHT/... Low pressure will develop along the Mid Atlantic coastline Wednesday. This will continue to allow for high level moisture over the region and partly sunny conditions over southern areas. Sunshine will increase as you head north, similar to Tuesday's conditions. This will allow for temperatures to climb to 75 to 80 degrees across the far north. With onshore winds out of the southeast, temperatures will be cooler along the coastline as cold air advects off the Gulf of Maine. This system then tracks into southern New England Wednesday night as it follows a stalled out boundary which gradually shifts north during the night. The Euro model ensemble solutions suggest PWATs will rapidly be on the increase Wednesday night approaching 2 inches off the coastline in the Gulf of Maine. Showers may become heavy by late evening and the precipitation may train over the same areas with a movement from southwest to northeast. Locally, over an inch of rain may fall during the night however the model consensus from run to run and model to model has been pretty poor over the last few days. Plenty of low level moisture will allow for fog to develop in southern areas Wednesday night as well. && .LONG TERM /THURSDAY THROUGH TUESDAY/... An anomalously deep summertime trough across the Southeast coast is supporting training surface low development along the quasi- stationary front off the eastern seaboard. The upper level trough will start to lift north Thursday into Friday, shifting the cyclogenesis northward. This slight shift places the frontal boundary and a weak surface low over the Gulf of Maine and coastal counties on Thursday. Hi res guidance shows the axis of heaviest rainfall south of the boundary where PWATs jump close to 2" and warm cloud depths increase to >12k feet. The track also supports S/SE flow which will drive moisture into the foothills where upslope will expand the rain shield inland. This is a notable shift from the previous day's forecast, but several models are showing a fair amount of consistency in the track which places the the potential for moderate to heavy rain along the coastal counties. Inland locations could also see locally moderate pockets of rainfall, but QPF totals should be <0.25". However, timing could change if the system speeds up as some indicate. There is some tall-skinny cape present, but for now am holding off any mention of thunder. For the northern mountains regions the precipitation will be more stratiform and lighter. expect an expansive cloud shield over the area Thursday which will help dampen temperatures. With the passage of the surface low late Thursday the boundary should be driven back offshore with drier high pressure pushing back in. The upper level trough will drift over the area on Friday followed by brief ridging. At the surface, the high will slide offshore supporting a return flow and increasing humidity. Unfortunately, another (much weaker) mid level trough will build back on Saturday night with increasing scattered showers and thunderstorms on Sunday. For Monday a stronger ridge will build over the eastern U.S. with rising heights by Monday and Tuesday. Overall temperatures will be dampened by clouds/rain on Thursday with highs in the lower 70s. Look for warmer conditions Friday into Saturday, at which time humidity values will creep back upwards. Rain chances and clouds Sunday, with continued warm and humid conditions for the start of next week. && .AVIATION /22Z TUESDAY THROUGH SUNDAY/... Short Term...Mainly VFR conditions expected through Wednesday, however the northern valleys will have patchy fog and localized IFR or LIFR conditions tonight. Showers and patchy fog will enter the region Wednesday night. This will lower visibilities into IFR with localized LIFR conditions. Long Term...Shra will reduced vsbys and Cigs mainly MVFR Wednesday night as a low pressure system moves into the area. Expected to grad lower to IFR for terminals along the coast where heavier rain is possible. Winds will shift to the S/SE with the low passage. Inland CIGs will vary from VFR with periods of MVFR, to MVFR with periods of IFR in any fog. && .MARINE... Short Term...A light southwesterly flow tonight will gradually back to the southeast Wednesday and Wednesday night as a weak area of low pressure approaches northern New England from the mid Atlantic region. Visibilities will be restricted Wednesday night over the waters in showers and developing fog. Winds will switch to the northeast late at night. Winds and seas will remain below SCA. Long Term...Winds and waves expected to remain below SCA throughout the long term. Look for a wind shift with the low passage Thursday, with worsening conditions offshore where S winds could reach 20kt. Over the weekend return flow out of the S/SW will bring in some longer swells which could bump waves up a foot or so, but nothing expected to exceed 3 ft at this time. && .HYDROLOGY... A weak area of low pressure will form along a stalled out front off the Eastern Seaboard Wednesday. This system will track across southern New England Wednesday night before crossing northern New England Thursday morning. Precipitable water values increase rapidly Wednesday evening allowing for showers, some of them heavy, to develop during the overnight hours into Thursday. Will need to monitor model trends closely as there will be rises once again on small rivers and streams. WPC has increased rainfall totals to around an inch on the coast and added a marginal risk of excessive rain. Upslope is expected in the S/SE flow ahead of the low passage, which will expand the rain shield inland. However, rainfall amounts and intensity will be much less as the PWAT gradient will be very tight across the area. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ SYNOPSIS... NEAR TERM...Cannon/Cempa SHORT TERM...Cannon LONG TERM...Jamison AVIATION... MARINE... HYDROLOGY...