Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 281407 AFDGYX Area Forecast Discussion National Weather Service Gray ME 1007 AM EDT Sun May 28 2017 .SYNOPSIS... Weak high pressure will remain over the area through today only slowing shifting east tonight. The next system over the eastern Great Lakes will lift north into Quebec tonight and will send a front towards the region. An area of showers will slowly cross New Hampshire and western Maine on Memorial Day. Warmer weather returns by the mid to latter part of the week but with the chance of showers each day. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 10 am Update: Sunny skies across region and temps recovering nicely from overnight lows. Raised max temps a few degrees over inland areas due to full sun into the afternoon before clouds develop. The coastal areas already seeing the dreaded seabreeze kick in which will keep temps much cooler. No other changes attm. 850 am update: Quick update to reflect sunny skies across the region thru the rest of the morning into the afternoon. All the early morning fog has burned off. Made adjustments to the sky grids to reflect the clear skies into the afternoon before some clouds develop and maybe widely scattered showers across some interior portions by mid/late afternoon. Update...GOES-16 visible imagery is showing marine stratus/fog rapidly lifting this morning under full sun. The river valleys are taking a little longer...but beginning to show signs of erosion on the edges. The NH Seacoast and adjacent SWrn ME looks to be a little more stubborn however...as high clouds have moved over the top of the low level stratus. This will limit mixing and dispersion of those clouds into mid morning. Previous discussion...Trapped low level moisture is leading to some slow developing stratus this morning. A weak s/wv trof is passing overhead and providing just enough lift to couple with nocturnal cooling to spread those clouds inland. At this point fog is confined to just RKD...so I do foresee this being a hazard beyond aviation interests this morning. Daytime heating will allow the remaining stratus to lift...and inland especially should see plenty of sun early. This will allow for more widespread 70s today. As the day warms up this will allow some convective showers to get going on the higher terrain. I do not expect these to be particularly fast moving...and mainly tied to the terrain...so the PoP is mostly for the mtns. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... Ridge departs tonight and allows return flow to set up. Clouds will increase from the W thru the night as the next low pressure sends a cold front our way. Appreciable precip looks to hold off until after 12z. Model guidance is in fair agreement that this will be fairly well organized as it reaches the CT River Valley...but over time will weaken and wash out as it fights the ridge to the E. So PoP starts high categorical midday...and trends towards likely by late afternoon over W central ME. The onshore flow...clouds...and precip will make for another relatively chilly day. Memorial Day is not looking like one to remember weather-wise. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... The deterministic models remain in decent agreement on the longwave pattern through late next week. We begin the period with an upper trough centered over the upper Great Lakes. The upper trough axis will gradually shift eastward into the northeast CONUS...where it will remain for the balance of the new work week and into the upcoming weekend. Temperatures this period should average below normal as troughing and below normal heights continue to dominate across New England. In the dailies...Low pressure centered north of the Great Lakes will push a slow-moving occluded front across the region Tuesday and Wednesday with onshore flow and the advancing baroclinic zone providing a damp start to the first half of the new work week. Behind this frontal system...the unsettled weather will continue as an upper trough remains parked across the northeast CONUS and a series of associated weak cold fronts or surface troughs cross the forecast area. && .AVIATION /14Z SUNDAY THROUGH THURSDAY/... Short Term...Mainly VFR expected across the area thru Sun night. In the near term however...weak flow is keeping low level moisture more or less in place. Especially behind the sea breeze front this is allowing some stratus to form. Areas of IFR will be possible from PSM up thru AUG and RKD...though confidence is low on timing and duration. I cannot rule out an isolated SHRA in the higher terrain today...mainly affecting LEB or HIE. A more widespread rainfall looks likely Mon...with widespread MVFR possible as the front moves in from the W thru the day. Long Term... Tue - Wed...MVFR in shra with lcl IFR in fog and drizzle. Thu...Areas of MVFR in -shra. && .MARINE... Short Term...Winds and seas to remain below SCA thresholds thru Sun night. Sly flow ahead of the approaching front Mon may bring a few seas to near 5 ft outside of the bays. Long Term... Tue - Thu...Conditions could approach Small Craft outside the bays. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$

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