


Area Forecast Discussion
Issued by NWS Portland, ME
Issued by NWS Portland, ME
426 FXUS61 KGYX 300547 AFDGYX Area Forecast Discussion National Weather Service Gray ME 147 AM EDT Sat Aug 30 2025 .SYNOPSIS... An upper low slowly moves east across the area today and exits into the Canadian Maritimes Sunday. Mostly dry conditions likely prevail through the weekend, although the presence of the upper low will bring slight chances for showers today. Broad high pressure builds in Monday and will provide mostly dry conditions through much of next week. && .NEAR TERM /TODAY/... Impacts and Key Messages: * No significant weather impacts are expected. The last of the showers are moving through Waldo and southern Somerset counties and out of our area at the time of this writing. Some showers may still come onshore on the Midcoast over the next couple of hours, but we should be done with all activity by daybreak. Overall, many locations received a beneficial rain with amounts generally 0.25-0.75". There were even some isolated amounts up to 1.50". With showers and thunderstorms out of the way, the holiday weekend looks quite pleasant. We will still be under the influence of an upper level low as it becomes centered north of the International Border today. This likely results in more clouds than sun for much of the area as a cold pool aloft aids in the development of clouds, thickening heading into the afternoon. Shortwaves rounding the upper low may help to touch off some showers during the afternoon hours as well. While showers are most likely in the mountains where lift is maximized, the 00Z CAMs are showing some isolated showers in the foothills and near the southern Maine coast. This suggests the cold pool may be a bit more robust, but mid level moisture looks fleeting in southern zones as well so kept low chance PoPs in the foothills, but I am skeptical on shower activity near the coast. Either way these will be just light nuisance showers. In the mountains, an isolated rumble of thunder and/or a heavier downpour aren`t out of the question. The increased cloud cover will hold temperatures in the low to mid 70s south of the mountains, and in the low to mid 60s to the south. && .SHORT TERM /TONIGHT THROUGH SUNDAY/... Impacts and Key Messages: * Apparent temperatures in the higher terrain (above 2500 ft) will fall below freezing tonight. Anyone planning to camp in these areas should be prepared for winter-like conditions. Tonight: Skies should clear south of the mountains leading to a fairly uniform temperature gradient across the area, with most locations falling into the 40s (lower to the north, higher to the south). This is a result of the upper low shifting eastward and cooler air advecting out of Canada. This will drive temperatures in the higher terrain down to near freezing and with winds staying up overnight there, apparent temperatures will feel well below freezing the higher up one ventures. Anyone planning to camp in the mountains this weekend should be well aware of this and plan for some winter like conditions. Patchy fog development is likely in areas that stay clear. Sunday: The upper low becomes centered over Atlantic Canada Sunday, but models suggest a shortwave trough axis reaching back through our area. With a cold pool still present, I would expect a similar situation to today (Saturday), but cooler drier air continuing to be advected in may limit clouds, and should certainly limit showers, making for a sunnier day in many locations. Would expect any showers to stay confined to the mountains, but if the cold pool remains robust it would not be out of the question to see a shower elsewhere. However, the 00Z CAMs are not as enthusiastic about it so I have hedged away from it as well, keeping PoPs in the mountains. Expect a slightly warmer day with temperatures rising into the mid to upper 70s south of the mountains, and into the upper 60s and low 70s to the north. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... Overnight NBM Update...No significant changes noted in the latest NBM with PoPs generally less than 15 percent for much next week until Thursday and Friday when chance PoPs are introduced. Previously... Key Message: Near to below normal temps continue thru the extended. Very little in the way of addition precip after today...so continued drying anticipated. Impacts: No significant weather impacts anticipated beyond maintaining/deepening drought conditions. A well timed high pressure could also bring the potential for frost in some northern valleys...but confidence in timing is low on that. Forecast Details: Lower heights/colder temps aloft will continue to promote diurnal cumulus development Monday while incoming high pressure will keep the area mostly dry. Day time temperatures generally moderate early next week, while it will be seasonably cool overnight...where surface high pressure and dry conditions will be favorable for radiational cooling. The timing of the surface high axis will dictate which nights are the coldest...but some northern valleys may potentially be frosty. The main story continues to be that beyond the weekend there is not much rain in the forecast again. Drought conditions may continue to expand. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... Short Term...Any fog that develops early this morning will quickly clear after 12Z. Otherwise VFR ceilings are expected to prevail through the day with some isolated shower activity in the area this afternoon. Northeasterly wind gusts around 15kts are likely this afternoon. Patchy fog development is expected again at valley terminals tonight, with VFR otherwise prevailing through the day Sunday. Long Term... Generally VFR conditions thru the extended. Some local MVFR is possible at KHIE Monday. Otherwise local IFR or lower in valley locations where fog is expected. Given the dry weather this may stay limited to HIE and LEB. && .MARINE... Short Term...Wind gusts and seas remain below SCA criteria through Sunday as high pressure builds over the waters. Winds will be generally northeasterly, with afternoon seabreezes. Winds gusts are expected to be generally 10-15kts, with seas 2-3ft. Long Term...Ridging and surface high pressure will build in and dominate weather thru next week. As a result winds and seas are expected to remain below SCA thresholds. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR/SHORT TERM...Baron LONG TERM...Legro/Schroeter