Area Forecast Discussion
Issued by NWS Portland, ME
Issued by NWS Portland, ME
374 FXUS61 KGYX 290502 AFDGYX Area Forecast Discussion National Weather Service Gray ME 102 AM EDT Mon Sep 29 2025 .SYNOPSIS... High pressure remains over New England through early in the week with dry weather and warm temperatures. A cold front moves through Tuesday, allowing for much cooler and continued dry weather for midweek with potential frost. Warmer conditions return late in the week and next weekend as high pressure remains in place. && .NEAR TERM /THROUGH TODAY/... High pressure brings another warm and sunny day to northern New England today. Yesterday`s weak cold front brings in drier air for today, but temperatures still rise into the upper 70s to low 80s in most spots. Mid 70s are expected across the north, as well as along the MidCoast where a seabreeze keeps temps down a bit today. && .SHORT TERM /TONIGHT THROUGH TUESDAY/... A cold front moves through during the overnight hours tonight. Any isolated showers likely dry up before they reach the Canadian border, with the dry frontal passage occuring overnight. At the same time, high clouds associated with moisture from Tropical Storm Imelda stream into southern locations through the overnight hours. These clouds shouldn`t prevent much in the way of radiational cooling as lows drop into the 40s across the interior, and low to mid 50s along the coast and Southeast New Hampshire. Tomorrow will feature a change of airmasses behind the cold front. Much drier air moves in through the daytime as dew points drop into the 30s. Cooler air will also arrive during the daytime across the north where highs top out in the low to mid 60s. South of the mountains, a downsloping wind direction warms temps into the mid 70s in most spots with mostly sunny skies. These conditions will bring an increasing fire weather threat as fine fuels dry through the daytime. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... Early morning long term update...Very little change to the going forecast as 01z NBM and various other ensembles/deterministics remain dry through the period. Much cooler air arrives Tue night with frost possible far north. Wed and Thu nights will have a good chance of frost away from urban centers and the immediate coast. Wed night will be the coldest night with a freeze likely in our mountain and some foothill zones. No meaningful rainfall is expected within the next 7-10 days, possibly longer, so we expect the drought to worsen with RH values/fuel moisture conducive for wildfire spread although winds not forecast to be particularly gusty after Wednesday. Previously... Overview: A series of high pressure systems will persist over New England through next weekend with little to no chance for precipitation. Following a warmer than average Tuesday, cooler conditions return for Wednesday and Thursday before a warming trend begins late week through the upcoming weekend. Impacts: Frost is possible Wednesday and Thursday night. Otherwise, little to no weather related impacts other than continued drought conditions. Forecast Details: Cooler temperatures will begin to filter in Tuesday night with lows falling into the 30s across the north with 40s elsewhere under clear skies. Cooler and more seasonable temperatures then return on Wednesday with highs ranging from the 50s across the north with lower to middle 60s south. It will be a bit breezy due to the pressure gradient between the high that will be across New England and tropical cyclone Humberto, which will be passing over the open North Atlantic. Northerly wind gusts up to 25 mph are therefore possible. Clear skies and weakening winds on Wednesday night will allow for radiational cooling with lows falling into the upper 20s across the north with 30s to near 40 south and along the coast. Thursday will be another cool day with highs into the 50s to near 60 degrees despite a plethora of sunshine. This will be followed by another potentially frosty night with lows into the 30s in most locations. High pressure will begin to sink a bit to our south for the remainder of the week and into the upcoming weekend, allowing for increasing WAA southwesterly return flow and thus warmer temperatures. Dry conditions look to persist for the foreseeable future as well. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... Short Term...VFR prevails during the daytime today and tomorrow. Valley fog with LIFR conditions are likely through mid morning today, and then again tonight at LEB. Valley fog is also possible at HIE and CON late tonight. VFR prevails elsewhere. Long Term...Other than nighttime valley FG most nights at KLEB and KHIE, mainly VFR conditions will prevail through the period. Northerly winds may gust up to around 20 kts on Wednesday but otherwise winds should largely remain light through the period. No LLWS is currently anticipated. && .MARINE... Short Term...Fair conditions continue with high pressure in place across the waters today. A cold front crosses the waters late tonight, with high pressure building in during the daytime tomorrow. A south- southeasterly swell builds during the daytime tomorrow, with SCA conditions possible with a 5ft swell possible by late tomorrow afternoon. Long Term...SCA conditions possible Wed and Wed night as high pressure builds in. These conditions subside on Thu. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR TERM...Clair SHORT TERM...Clair LONG TERM...Ekster/Tubbs