Area Forecast Discussion
Issued by NWS Portland, ME
Issued by NWS Portland, ME
136 FXUS61 KGYX 120624 AFDGYX Area Forecast Discussion National Weather Service Gray ME 224 AM EDT Sat Sep 12 2026 .WHAT HAS CHANGED... No significant changes with this forecast update. && .KEY MESSAGES... 1. Low pressure forming near southern New England followed by a cold front will bring a period of rain and perhaps a rumble of thunder or two tonight through Sunday afternoon. 2. High pressure builds in for the first half of next week, with chilly and crisp Fall weather forecast. && .DISCUSSION... KEY MESSAGE 1 DESCRIPTION... After early morning valley fog lifts, today will be another fair weather day as the center of SFC high pressure moves offshore. This will result in a relatively light southerly wind with temperatures well into the 70s at most locations. Sunny skies will give way to increasing clouds during the afternoon. A positive IVT plume and associated increase in PWATS will impinge on the forecast area ahead of a short wave trough tonight into Sunday. Chances for rain will increase from southwest to the northeast as the night progresses. The most precipitation should be across southern NH based on a multi- model consensus. Up to a half inch of rain is forecast there, with lesser amounts as one heads north. A few rumbles of thunder will be possible as MUCAPE becomes weakly positive. Showers, possible heavy at times will continue through mid Sunday afternoon across southern and coastal zones while interior locations begin to dry out. KEY MESSAGE 2 DESCRIPTION... A cold front moves in Sunday night, with some isolated to scattered showers possible through Monday morning. After the passage of the front, breezy northwesterly winds kick up and high pressure looks to be overhead by Monday night. Winds will calm and skies will be clear, resulting in radiational cooling. Tuesday morning lows are likely to be in the lower 40s, with upper 30s north of the mountains. Frost could certainly be a possibility across locations north of the mountains, but confidence is still low. Some cloud cover moves in during the day on Tuesday, and should prevent radiational cooling through the rest of the week. && .AVIATION /08Z SATURDAY THROUGH WEDNESDAY/... Through Sunday night...Valley fog at LEB and HIE persists through mid-morning today. VFR expected at most terminals through 06z Sunday with light southerly winds. A deterioration of conditions is then expected later tonight with MVFR and then IFR conditions overspreading the area from west to east. IFR conditions are expected much of Sunday with some improvement foreseen late in the day and night, although fog may be an issue later Sunday night. Outlook: Monday: MVFR possible early Monday morning trending towards VFR by mid to late morning. Tuesday-Wednesday: VFR expected, except conditions will be favorable for valley fog at LEB and HIE. && .MARINE... High pressure slides over New England through tonight for quiet conditions on the waters. Southerly winds increase tonight through Sunday as a trough approaches while winds and seas remain below SCA thresholds. A cold front crosses Sunday night shifting winds offshore with winds and seas still remaining below SCA thresholds. High pressure then builds in Monday through Wednesday. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ DISCUSSION...Ekster/Palmer