Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 241102 AAA AFDGYX Area Forecast Discussion...UPDATED National Weather Service Gray ME 702 AM EDT Sat Jun 24 2017 .SYNOPSIS... Tropical moisture from the remnants of Tropical Storm Cindy and a passing frontal system will bring scattered showers and thunderstorms this morning. A series of surface troughs and weak cold fronts will cross the area this weekend into early next week bringing us the chance of showers from time to time... especially in central and northern areas. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 702 AM Update... Showers and convection are marching southeast this morning along a frontal boundary with some heavier downpours especially along the front edge. Ahead of this widely scattered showers are occurring. No lightning is reported so far but am watching cells which have very heavy rain according to instantaneous dual-pol estimates. Minor changes to the forecast database include temperature and dew point updates. Previous discussion... Shower activity is beginning to pick up again across eastern and northern sections of the forecast area with the approach of a frontal system. Convection will be less focused with a pre- frontal trough as well as a cold front crossing the region and broad but weak instability. QPF looks light overall but there is still the possibility of heavy downpours... especially over the mountains...with moisture from TS Cindy lingering. A few rumbles of thunder are possible but overall instability is weak. Convection should exit the coast by mid-morning with the remnants of Cindy moving offshore near Cape Cod bringing additional showers to Portsmouth and the islands in the Gulf of Maine. This baroclinic zone sits offshore with additional short wave energy moving along it and producing rainfall well off the coast this afternoon and evening. Drier air moves in today with temperatures warming into the upper 70s to upper 80s with gusty SW to W winds in place. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... Another cold front will hang up along the Canadian border and produce showers and scattered thunderstorms for mainly the mountains Sunday...especially in the heat of the afternoon with readings warming into the 70s and 80s once again. A robust short wave approaches towards the late afternoon and evening increasing thunderstorm activity...but earlier cloud cover and showers will keep any strong storms from forming. Showers will diminish in the evening with drier air arriving and the loss of heating. Expect temperatures to fall back into the upper 40s/lower 50s in the mountains with mid to upper 50s to the south and east for overnight lows. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Upper air wave pattern this weekend features a building West Coast ridge and a broad trough over the eastern half of North America. This is allowing the southwestern deserts to bake while the center and eastern parts of the country enjoy cooler air spilling down from the northern parts of Canada. New England is in the southwesterly flow ahead of the broader Eastern trough with frequent waves tracking through the flow sending weak cold fronts through the region. During the first half of next week, a trough will drop down out of the Gulf of Alaska and help to squash the West Coast ridge to the east, in turn forcing the Eastern trough to make a move to the east. Once it exits a broad west to southwest flow will transport warmth from the middle of the continent eastward into New England late in the week. Expect gradually cooling temperatures Sunday through Tuesday as the Eastern trough slowly pushes into the area. Several waves within the broader trough will rotate through, with each of these waves potentially bringing a round of showers especially if they move through during the daytime. The best chance of showers and possibly thunderstorms will be Tuesday when the main trough axis crosses through New England. High temperatures will generally be in the 70s, with lows in the 50s. After the trough departs on Wednesday the ridge will begin affecting the area on Thursday as warm, humid air begins to spill into the area. A wave tracking through Ontario and Quebec will organize a warm front to push through New England on Thursday, the leading edge of the warmer air. Some showers can be expect along and north of that warm front while warm, humid weather will arrive south of it. The entire area looks to get into the warmer air by Friday. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... Short Term... Pockets of MVFR conditions are occurring this morning in lower ceilings/-SHRA and the occasional -TSRA associated with a cold frontal passage. TS Cindy is also contributing to the moist airmass. Fog has yet to affect RKD but is expected to affect them briefly. Most of the dense fog is expected to remain over eastern Maine and offshore this morning. Conditions improve to VFR as drier air works in today on developing gusty westerly winds. Winds diminish after sunset. Long Term...Generally expecting VFR conditions late this weekend through the middle of next week. However, occasional showers are also possible especially each afternoon, mainly in the interior. && .MARINE... Short Term...Winds will be dropping today with the generic SCA likely to be replaced around mid-morning by a SCA for hazardous seas for perhaps the easternmost outer waters for a few more hours. Winds/waves continue to subside tonight. Long Term...Expect a general light westerly flow over the waters through the first half of next week. && .TIDES/COASTAL FLOODING... Astronomical high tides will continue through the weekend with the possibility of minor flooding particularly with the tide late tonight at 12:05 AM at Portland. The astronomical high tide will be 11.9 feet with a storm tide overnight likely coming in between 12.2 and 12.7 feet. With little in the way of wave action, expect only very minor issues along the coastline. A headline of some sort will be needed today to cover this concern. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until noon EDT today for ANZ150-152-154. && $$ NEAR TERM...Hanes SHORT TERM...Hanes LONG TERM...Kimble

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