Area Forecast Discussion
Issued by NWS Portland, ME
Issued by NWS Portland, ME
780 FXUS61 KGYX 020630 AFDGYX Area Forecast Discussion National Weather Service Gray ME 230 AM EDT Fri Oct 2 2026 .WHAT HAS CHANGED... No significant changes with this forecast update. && .KEY MESSAGES... 1. Very warm conditions continue today before a cold front crosses this afternoon and evening bringing some showers and a cooler airmass for the weekend. 2. Another cold front crosses the region Sunday night-early Monday. The coldest weather of the fall so far is likely to arrive behind it. && .DISCUSSION... KEY MESSAGE 1 DESCRIPTION... Latest surface analysis places a cold front along the St Lawrence Valley southwestward into the Great Lakes. Temperatures will likely remain in the 60s through early this morning setting a high floor for temperatures today before the cold front crosses this afternoon and evening. Despite skies turning mostly cloudy by peak heating temperatures today are still on track to climb into the upper 70s to low 80s south of the mountains. More in the way of clouds this morning and shower chances arriving this morning will limit highs along and north of the mountains to the 60s. Latest CAM guidance focuses the best chances for showers along and north of the mountains this morning with showers struggling to hold together as the progress towards the coast this afternoon. Based on latest trends many areas south of the mountains may fail to realize measurable rainfall. For those that do see some showers QPF amounts will generally be a tenth of inch or less with isolated higher amounts if any convective processes can materialize. The front will be pushing offshore around sunset with skies clearing tonight. This will likely allow for valley fog tonight with lows ranging from the upper 30s north to near 50 degrees along the coast and southern NH. High pressure will build in Saturday for fair weather with highs ranging from the upper 50s north to upper 60s south. High pressure cresting over the area Saturday night will allow for favorable radiational cooling conditions that could allow for lows into the upper 20s north with frost potential expanding south of the foothills. KEY MESSAGE 2 DESCRIPTION... An amplified trough approaches the region late Sunday, dragging a cold front through New England on Monday. Despite a rather strong temperature gradient, it looks like a bit of a glancing blow with the surface low and best dynamics well to the north up in Quebec. Generally looks like two embedded precipitation chances: 1.) Southern stream energy possibly clipping the southern half of the forecast area Sunday night, although about half of current solutions keep the rain fully south of our forecast area. 2.) Along the cold front during the day Monday, best chance will be across northern NH and NW Maine closest to the best forcing. Neither wave is a slam dunk or expected to bring significant soaking rains due to quick shortwave motions and a lack of deep moisture. In fact, there is the chance a sizable chunk of the forecast area sees a dry frontal passage with the two waves splitting the area. The real cool down arrives by Tuesday morning. Very likely the coldest weather since the spring arrives Tuesday-Wednesday with 850 mb temperatures plunging to between 0 and -7C by Tuesday morning depending on model of choice. Even 925 mb temperatures are near or slightly below freezing on guidance. NBM currently shows lows reaching the upper 20s-low 30s in the interior with 30s all the way to the coast, which would easily be the coldest morning of the fall so far. However these low temperatures are contingent on the boundary layer decoupling, and guidance is currently indicating 40- 50+ kts at 850 mb driven by a strong pressure gradient, so would say the temperature forecast here is not yet high confidence. Won`t take much mixing on Tuesday to tap the stronger winds aloft, so can expect a blustery day, and with highs that will struggle to hit 60, there will be a fall chill in the air. Dry and sunny conditions should last through Wednesday with high pressure cresting overhead. Likely will see another cold start despite 850 mb temps not as cold as better decoupling will be likely with a slacking pressure gradient, but strong surface heating should once again allow for comfortable daytime temperatures. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... VFR conditions are expected to continue through the first half of today. Late morning a front sags into the area bringing lowering cigs and SHRA to HIE that likely bring a period of at least MVFR. As the front moves south local MVFR conditions will be possible in any steady/heavier rain rates through the afternoon while any restrictions will likely be brief. Clearing skies tonight will promote valley fog, especially around HIE and LEB. Outlook... Saturday-Sunday: Generally VFR conditions are expected as high pressure moves through the region. Monday: Generally VFR with some brief MVFR restrictions possible in light rain and/or snow along and north of the mountains. Tuesday: VFR prevails once again as high pressure once again builds into the region. && .MARINE... Southwest winds will gust 15 to 20 kts through early afternoon ahead of a cold front with seas generally less than 5 feet. The front crosses the waters tonight shifting winds offshore while winds and seas likely stay below SCA thresholds. High pressure builds in Saturday and shifts east of the waters Sunday. A cold front crossing Monday into Tuesday will bring potential for SCA conditions in strong CAA. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ DISCUSSION...Barker/Schroeter