Area Forecast Discussion
Issued by NWS Portland, ME
Issued by NWS Portland, ME
862 FXUS61 KGYX 081046 AFDGYX Area Forecast Discussion National Weather Service Gray ME 646 AM EDT Tue Sep 8 2026 .WHAT HAS CHANGED... No significant changes with this forecast update. && .KEY MESSAGES... 1. A weak cold front will sink south through the area early this morning bringing light showers across northern NH into western Maine. 2. A seasonably strong low pressure system will drag a cold front across the area late Wednesday into Thursday with showers becoming likely late Wednesday and Wednesday night. 3. A period of gusty winds will be possible on Thursday behind the front with dry weather returning late week through at least Saturday. && .DISCUSSION... KEY MESSAGE 1 DESCRIPTION... Latest surface analysis shows a west to east oriented cold front moving south through the St Lawrence Valley early this morning. Latest radar shows light showers along and ahead of the front. As the front continues south these showers will move across the International Border and into the mountains before day break. While the front will wash out over the area later this morning, recent runs of hi res guidance some light showers will hold together as they move south of the mountains towards the Maine coast through mid morning. Shower chances diminish around mid day with skies turning mostly sunny during the afternoon as high pressure rebuilds into the area from the north. Highs will range from the upper 60s north to low 80s south. KEY MESSAGE 2 DESCRIPTION... An upper low will start to deepen over northern Ontario early on Wednesday, cross the Hudson Bay at night, and move into northern Quebec on Thursday. An associated surface low will drag a couple of cold fronts across the region Wednesday night through Thursday, leading to increasing chances of showers Wednesday afternoon. The best chances for widespread rain will be Wednesday night (50 to 90 percent) with PWATs forecast to be anomalously high for this time of year. Thus, there could be some locally heavy downpours but the heaviest showers should move through rather quickly Wednesday night. Trends continue to suggest that the best chances will be across northern New Hampshire and the western Maine mountains but almost everywhere will likely see at least some measurable rain. Given the progressive nature of the system, it seems reasonable that totals will mostly be in the 0.25 to 0.50 inch range, but some higher amounts will be possible under any heavier showers that do move overhead. Unfortunately, it looks like southern New Hampshire and southwest Maine may once again miss out on the higher totals and will likely see less. Rain chances will decrease early to mid Thursday morning, but some showers may linger across the north through the afternoon. Regarding temperatures Wednesday: clouds will be on the increase, which should lead to cooler temperatures but increasing dewpoints. Highs are forecast to mainly range from the upper 60s and lower 70s north, to the low to mid 70s across western and coastal Maine, and the mid to upper 70s over southern New Hampshire. A few lower 80s will be possible near the Massachusetts border. KEY MESSAGE 3 DESCRIPTION... Winds will really start to increase out of the west Thursday afternoon behind the secondary cold front after it sweeps through. Strong cold air advection and decent 3-hour pressure rises (2 to 4 mb) will provide favorable conditions for gusty winds to mix their way down to the surface. Depending on the location, the latest NAM soundings suggest anywhere from 25 to 40 knots at the top of the mixed layer. Thus, we should see widespread gusts in the 25 to 35 mph range with some sporadic gusts up to 45 mph Thursday afternoon. High temperatures on Thursday will be warmer for those ahead of the secondary front with some low to mid 80s possible across the southern half of New Hampshire and interior/coastal Maine. Thursday night will see some cooler lows behind the front, but lingering breezy winds and cloud cover will keep temperatures from bottoming out too much. Forecast lows range from the mid to upper 40s north, to the mid to upper 50s south and along the coast. Friday will be cooler, dry, and breezy with northwest winds gusting up to 30 mph or so through the first part of the day. Highs will mainly range from the low to mid 60s north, to the low to mid 70s south. Winds then relax under a clear sky Friday night which will lead to fantastic radiational cooling conditions. Expect widespread lows in the 40s with some 30s possible in the northern valleys. The next trough and front will approach on Sunday, leading to our next low chances of precipitation. Expect highs mainly in the 70s through the weekend and into the next work week with a couple of lower 80s across far southern New Hampshire. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... Through Tuesday night...Mainly VFR through day break. Any remaining LIFR at LEB improves by midmorning. Brief showers will be possible through 15Z this morning at HIE, AUG, and RKD. Largely VFR conditions expected today through tonight outside of valley fog. Outlook: Wednesday: Mainly VFR but MVFR possible later in the day as clouds thicken and lower with chances for showers. Wednesday night: A cold front brings widespread showers and restrictions. Highest chances for showers and IFR to even LIFR will be at HIE-AUG-RKD with lesser confidence in degree of restrictions toward PWM and the southern NH terminals. Gusts out of the S to SW around 20 kt possible. Thursday: Mainly VFR with west winds gusting 25-30 kt, possibly as high as 35 kt. Thursday night-Saturday: Mainly VFR. Valley fog possible at HIE and LEB by Friday night. && .MARINE... Winds and seas are expected to remain below SCA thresholds through tonight. Southerly winds will begin to increase Wednesday as low pressure treks east across Hudson Bay while winds remain below 25 kts during the day. SCA conditions are likely Wednesday night into Thursday as south winds continue to strengthen and shift SW as a cold front approaches from the NW. The initial front crosses Thursday morning with a secondary front crossing later in the day shifting winds out of the NW. Conditions improve Friday and Saturday as high pressure builds across the waters. The high shifts east Sunday into Monday as another front approaches from the west. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ DISCUSSION...Hargrove/Schroeter AVIATION...Clair