


Area Forecast Discussion
Issued by NWS Portland, ME
Issued by NWS Portland, ME
666 FXUS61 KGYX 290548 AFDGYX Area Forecast Discussion National Weather Service Gray ME 148 AM EDT Fri Aug 29 2025 .SYNOPSIS... Low pressure over Quebec will send a cold front across the area today bringing scattered showers and thunderstorms. An upper low will slide across northern Maine through the weekend that will continue chances for showers, mainly across the mountains and north. High pressure builds in Sunday and Monday for fair weather and temperatures warming back into the upper 70s by Monday. Dry conditions are likely to prevail through the middle of next week. && .NEAR TERM /TODAY/... A vigorous shortwave digs into the Northeast today, bringing rounds of showers and thunderstorms through the day. Convection is expected to blossom across New Hampshire and western Maine by late morning as cold air moves in aloft. Lines of showers and storms pivot northeastward through the day, with most areas expected to see multiple rounds through the day. Western New Hampshire likely sees one round during the early to mid morning hours, and then remains mostly dry through the remainder of the day. Elsewhere, multiple rounds are expected through the day, and continue into the evening. With multiple rounds of rain, the focus for higher rainfall amounts of a half inch to an inch of rain looks likely from the Lakes region of New Hampshire through the mountains and foothills of Maine. Some locally higher amounts are also likely with some heavier downpours. && .SHORT TERM /TONIGHT THROUGH SATURDAY/... Showers and storms weaken through the evening, but with cold air continuing to move in aloft shower activity looks likely to continue into the overnight across the northern mountains and into central Maine. Elsewhere, gradually drying is expected through the overnight. With the rain today, some patchy fog is expected through the overnight. The upper level low remains overhead during the day on Saturday. The day starts off on the sunnier side, but with the cold pool aloft clouds and showers develop by the early afternoon. Most of the showers are likely to be across the higher terrain and into central Maine. Isolated showers are expected elsewhere, with more clouds than sun for the afternoon in most spots. Temps only warm into the low to mid 60s across the north, with low to mid 70s elsewhere. Most of the warming occurs through the morning, and then temps will generally hold steady through the afternoon. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... 01Z NBM Update...No significant changes with the latest NBM through the long term period. A trend to mostly dry conditions are likely by Monday with surface high pressure likely to hold over the Northeast through the middle of next week. Troughing deepens over the eastern CONUS the second half of next week that may allow better moisture transport into the Northeast. Ensembles suggest the next shot at some beneficial rainfall will arrive towards the end of next week. Previously... Key Message: Some cooler weather thru the extended...but continued dry conditions will likely contribute to at least maintaining drought status. Impacts: No significant weather impacts anticipated beyond maintaining/deepening drought conditions. A well timed high pressure could also bring the potential for frost in some northern valleys...but confidence in timing is low on that. Forecast Details: The extended will begin with upper low lifting out of the region. Currently the NBM has some showery weather lingering into Sun...especially over the higher terrain...but dry by Mon. However DESI does show two clusters with a deeper trof/cooler temps aloft lingering over the region into Mon. This is roughly 35 to 40 percent of ensemble members...and would likely result in some afternoon convective showers. If ensemble forecasts continue and NBM still does not show much in the way of PoP I may look to increase them with subsequent forecast. Otherwise temps will average near to below normal. The building ridge will be of CONUS origin...so not particularly cool. However a well timed surface high would lead to some efficient radiational cooling and potential for frost in northern valleys. The main story will be that beyond the weekend there is not much rain in the forecast again. So unless we get significant rain in the next couple of days...the drought conditions are likely to worsen. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... Short Term...Some valley fog at HIE and LEB remains likely through mid morning, while some marine fog and stratus remains possible at AUG and RKD through mid morning. Multiple rounds of showers and a few thunderstorms bring restrictions to all terminals through the afternoon, with periods of MVFR conditions most likely. Conditions gradually improve tonight, but showers remains possible at AUG and RKD through the overnight. Valley fog is possible at LEB and HIE tonight. Mainly VFR conditions return tomorrow, but brief showers will be possible across northern terminals through the daytime. Long Term...Mostly VFR conditions expected in the extended. Heading into next week high pressure may promote more in the way of valley fog...and IFR or lower conditions for the favored sites. && .MARINE... Short Term...Showers and storms move through the waters today as a cold front approaches from the west. The front clears the waters tomorrow morning, with high pressure gradually building in on Saturday. Long Term...With upper low lifting out and ridging/surface high building in for next week...winds and seas are expected to remain below SCA thresholds. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR TERM...Clair SHORT TERM...Clair LONG TERM...Legro/Schroeter