


Area Forecast Discussion
Issued by NWS Portland, ME
Issued by NWS Portland, ME
911 FXUS61 KGYX 260758 AFDGYX Area Forecast Discussion National Weather Service Gray ME 358 AM EDT Sat Jul 26 2025 .SYNOPSIS... Areas of smoke from Canadian wildfires arrive overnight and continue through Saturday afternoon. High pressure moves overhead today, with seasonable temperatures and lower humidity. High pressure shuffles east as the next system moves in Sunday with chances of showers and storms. Heat and humidity begin to build again early next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 4am Update...Quick update to relay Air Quality Alert for Maine. Previous Discussion... High pressure settles over the region today bringing fair conditions. While yesterday`s cold front brought some afternoon relief, today will still see highs pushing into the 80s. Smoke entered the region Friday evening, pushing across the area overnight. Low level smoke has been impressive for a far remote source, with overnight observations reading 4 to 6 mile visibility across the forecast area. HRRR/RAP smoke models continue the plume over the area today, gradually decreasing in coverage and intensity as the day goes on. The lack of daytime mixing will help keep greater smoke content aloft from mixing down, but will also prolong some areas due to largely stagnant air. A afternoon seabreeze along the coast stands chance at thinning haze/smoke, but the better chance for relief may not come until flow turns southerly tonight. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... High pressure will move over the Gulf of Maine tonight, bringing a southerly return flow into NH and ME. It will be subtle initially, but increase into Sunday morning. After a mostly sunny day, clouds thicken into Sunday. This, and the following rain, will contain daytime highs in the 70s for southern and central areas. A 80 degree rating will be possible towards central ME where clouds may not become as thick as southern points. The main focus Sunday will be a rain along increased PWAT values advecting east along a channel of IVT. HREF and NBM bring measurable precip first into NH early Sunday morning, expanding east into southwestern ME through early afternoon. Associated moisture is transient however, and as the parent low tracks north into Quebec Sunday evening, rain becomes more showery and lighter. While PWATs push above 1.5 inch briefly, warm cloud layers remain around 10kft. Thus warm rain processes won`t be optimal. Additionally, backbuilding or training of showers/storms is not expected, but could still occur given a more favorable environment to the west. Due to continuing onshore flow across much of the area, surface instability is difficult to build through the day. This will further lower additional shower/thunderstorm development come afternoon. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Behind exiting wave, shortwave ridging builds in for Monday, providing the subsidence for a mostly dry forecast. However, the heat and humidity will ramp back upward with 850mb temps supporting highs in the upper 80s to lower 90s, and dewpoints may be enough to bring heat indices into the mid 90s in some areas. Another wave may bring some shower activity Monday night, mainly across northern areas, and then chances for showers and storms further increase on Tuesday and Tuesday night as a cold front approaches the region with daytime temperatures and heat index values potentially even climbing a degree or two on top of Monday`s. There remains uncertainty in how quickly the front will push south of the area, so Wednesday could end up being drier and slightly cooler or still pretty warm with lingering chances for showers and storms. There`s higher confidence in the front having cleared the area by Thursday with cooler and drier air settling in for Thursday and Friday as high pressure builds toward New England from the west. Aloft, an upper low will likely be somewhere near the Canadian Maritimes with troughing extending southward into the Northeast. So it`s possible a shortwave or two bring a few showers from time to time. Of note: The global models do indicate low pressure trying to develop along the frontal boundary, but the ECMWF is not as far south with front as other guidance. If this is the case, southern and coastal areas may see higher precipitation chances toward late week. However, this is a week out, and confidence is low. && .AVIATION /08Z SATURDAY THROUGH WEDNESDAY/... Short Term...Areas of wildfire smoke and haze bring MVFR visibility restrictions to most terminals into Saturday, likely lingering the longest around HIE and LEB into midday. It is possible some calm conditions allow for radiation fog to form in the deeper river valleys...like near LEB and HIE through this morning. Clouds thicken and lower Sunday morning as SHRA invade from the west for most NH terminals and far western ME terminals. MVFR to IFR ceilings will be possible Sunday morning through the afternoon. Long Term...Fog may then develop Sunday night into early Monday morning, but then VFR is expected the rest of Monday. Tuesday will see increasing chances for flight restrictions from showers and storms as a front approaches, but low ceilings/fog look to be a possibility Monday night or early Tuesday ahead of the front. Depending on the speed of the front, chances for flight restrictions and precipitation may linger into Wednesday. && .MARINE... Short Term...Light northwesterly wind continues this morning behind a passing cold front. As high pressure pushes over the waters, southerly return flow increases this afternoon through Sunday. Winds and seas will remain below SCA thresholds thru Sunday. Long Term...Conditions currently look to remain below SCA levels from Sunday through through much of next week. In general, high pressure becomes centered east of the waters as a weak front moves into the region Sunday followed by a more potent front toward midweek. High pressure builds toward the northeastern U.S. from the west late next week. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...Air Quality Alert until 11 PM EDT this evening for MEZ007>009- 012>014-018>028-033. Beach Hazards Statement from 8 AM EDT this morning through this evening for MEZ027-028. NH...None. MARINE...None. && $$ NEAR TERM...Cornwell SHORT TERM...Cornwell LONG TERM...Combs