Area Forecast Discussion
Issued by NWS Portland, ME
Issued by NWS Portland, ME
249 FXUS61 KGYX 301806 AFDGYX Area Forecast Discussion National Weather Service Gray ME 206 PM EDT Wed Sep 30 2026 .WHAT HAS CHANGED... Temperatures have been lowered for the rest of today based on trends in cloud cover. && .KEY MESSAGES... 1. Warmer temperatures are expected Thursday with mostly dry conditions continuing. 2. Through the weekend will be more of a typical fall pattern. A series of front cross the region with chances of showers followed by cool and breezy conditions. && .DISCUSSION... KEY MESSAGE 1 DESCRIPTION... Although guidance has not handled it well, models remain insistent in the low levels starting to dry this afternoon, which should lead to the stubborn deck of lower clouds eventually lifting and thinning out. Until then, drizzle is possible at times for the next couple of hours, mainly for SW Maine where cloud bases are currently lower. Prospects of seeing the sun this afternoon are fairly low already and are further dwindling as we`re already seeing high clouds moving in from the west, which should continue to increase and thicken this evening and tonight as a 500mb shortwave approaches. So highs for this afternoon have been knocked down a couple of degrees, but conversely these clouds should help limit radiational cooling tonight to keep temps mostly in the lower 50s. I do have patchy fog for most area tonight into Thursday morning, and HREF probabilities are really highlighting fog for areas along and east of the I-95 corridor in western ME, but coverage is in question due to the cloud cover. High pressure remains in control to keep conditions dry for the most part on Thursday. Model soundings depict some drying behind the wave that moves through tonight, so we should see more sun, at least through the first part of the day. Clouds then start increasing from west to east through the afternoon, more noticeably in NH (where a few sprinkles are possible), as moisture trends upward ahead of a frontal boundary. Otherwise, 850mb temperatures of +10C to +12C support highs reaching the mid-upper 70s, which will be roughly 10 degrees above normal for the first day of October. Clouds further increase Thursday night with a light S/SW breeze, which will both help hinder fog development and keep overnight lows very mild in the 50s and 60s. A few showers are possible in the mountains, but most will be dry. KEY MESSAGE 2 DESCRIPTION... Fri will be one more very warm day as we remain in the WAA ahead of the next approaching front. All guidance is pointing towards 10 to 15 degrees above normal across the forecast area. This will mean some locations may make a run at 80 degrees. Very warm for sure, but looking to be at least 5 degrees below records for this time of year. The NBM may also be running slightly warm as we start to transition out of the warm season and into the cold season. Precip with the front will be showery in nature and forcing not strong along the boundary. I suspect that some areas will miss out on rainfall or not amount to much. This first front will serve to knock temps back to normal for the weekend. With the clear and calm night looking to be Sat night, that should be the coldest. I anticipate some frost into the foothills, but those zones will no longer be active in the frost/freeze program. However a stronger shortwave is forecast to cross the region late Sun into Mon. This is much lower confidence on rainfall. Ensemble members are less than 50/50 on measurable rainfall across the forecast area, especially the farther south you go. There is higher confidence that some cooler than normal air follows in its wake. Tue temps may not get out of the 50s under mostly sunny skies along with breezy westerly winds. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... Through 18Z Thursday...Stubborn MVFR deck should gradually trend toward VFR through this afternoon. After that, mainly VFR through the TAF period. Valley fog is possible tonight at HIE and LEB but could be limited due to too much cloud cover. Another area to watch for IFR fog and/or stratus is in the PWM- AUG-RKD corridor tonight into mid morning Thursday. Outlook: Rest of Thursday: Mainly VFR, but marine fog may linger near PWM and RKD in the afternoon to early evening. Thursday night: Mostly VFR. Again, valley fog could develop at HIE and LEB, but more clouds ahead an approaching front may limit development. This front could bring a few showers to HIE late. LLWS is possible. Friday: Areas of MVFR or lower possible in rain showers. Saturday: VFR conditions expected. Local IFR or lower overnight in valley fog. Sunday: VFR conditions expected. Local MVFR or lower conditions possible in rain showers. Monday: VFR conditions expected. Tuesday: VFR conditions expected. Westerly winds may gust up to 25 kt. && .MARINE... Through Thursday night...High pressure remains centered just offshore of the Mid-Atlantic that will keep prevailing southwest winds across the waters. These begin to increase late Thursday and Thursday night as a cold front approaches but are expected to remain below SCA levels. Winds and seas are expected to remain below SCA thresholds thru the weekend. Stronger CAA across the warm waters is likely to peak around Tue. This will be the most likely period for SCA conditions across the coastal waters and perhaps into the bays as well. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ DISCUSSION...Combs/Legro