Wednesday-Friday
An unsettled weather pattern will continue across the Valley Wednesday as low pressure brings widespread rain, low clouds, and patchy fog to northern Maine. Rainfall will become more scattered during the afternoon as the system gradually moves away, although cloudy skies and chilly temperatures will persist. Northwest winds will strengthen Wednesday night as cooler and drier Canadian air begins spreading into the region.
Thursday will provide a brief break between weather systems. High pressure approaching northern New England will bring increasing sunshine, but brisk northwest winds gusting near 30 mph will maintain a distinctly autumnal feel. Winds will diminish Thursday evening, allowing temperatures to fall well below freezing overnight, particularly in sheltered sections of the Saint John and Fish River valleys.
Another low-pressure system will approach Friday, bringing a return to unsettled weather and the possibility of the season’s first appreciable snowfall. Precipitation may begin as snow during the morning before changing to a mixture of rain and snow as temperatures rise into the 30s. Widespread precipitation is expected by afternoon and will continue Friday night as temperatures approach freezing.
The storm’s track will be particularly important in determining snowfall amounts. Higher elevations and colder locations should favor accumulating snow, while mixing and melting may limit totals in the lower valleys. Several inches of snow are possible in parts of northern Aroostook County, although the distribution of accumulation remains uncertain. Northeast winds will strengthen Friday night, adding to the increasingly wintry conditions.
Saturday-Tuesday
Friday’s storm system will gradually depart Saturday, although lingering moisture and a broad upper-level trough will maintain cold, unsettled conditions across northern Maine. Scattered snow showers may continue through the day, especially over higher terrain, but little additional accumulation is expected. Strong northwest winds will be another concern, with gusts approaching 40 mph creating blustery conditions and making temperatures in the 30s feel considerably colder.
Improving conditions will arrive Saturday night and Sunday as high pressure builds toward northern New England. Winds will diminish, skies will gradually clear, and Sunday should feature considerable sunshine. However, the colder Canadian air mass will remain in place, keeping daytime temperatures near 40 degrees F. Overnight temperatures will fall into the lower 20s both Saturday and Sunday nights, with particularly cold conditions in sheltered valleys.
A noticeable warming trend will begin Monday as the upper-level trough moves eastward and milder air spreads into the region. Temperatures will recover to around 50 degrees F Monday, accompanied by intervals of sunshine and increasing clouds.
The warming trend should continue Tuesday, with afternoon temperatures reaching the lower to middle 50s. Generally dry weather is favored, although passing clouds are possible as the atmospheric pattern becomes less amplified. Some uncertainty remains regarding the timing of upstream disturbances, but significant precipitation currently appears unlikely.
Looking Ahead: October 21-27
The Climate Prediction Center’s latest outlook indicates equal chances for above-, near-, or below-normal temperatures across northern Maine, while below-normal precipitation is favored. A broad ridge of high pressure over the central United States may encourage a relatively quiet weather pattern across the Northeast, although some uncertainty remains regarding temperatures. Equal chances does not necessarily mean temperatures will remain near normal, but rather that no particular temperature category is favored. Typical late-October conditions in the Saint John Valley feature daytime highs in the middle to upper 40s and overnight lows in the upper 20s to lower 30s.
Daily Forecast Summary
Wednesday: Rain and patchy morning fog, becoming scattered showers during the afternoon. Highs in the lower 40s. East winds turning northwest. Rain probability near 100%.
Wednesday Night: Scattered evening showers, becoming partly cloudy later. Lows in the middle 30s. Northwest winds 10-15 mph, gusting to 25 mph. Rain probability 40%.
Thursday: Mostly sunny and breezy. Highs in the middle 40s. Northwest winds 10-15 mph, gusting to 30 mph.
Thursday Night: Mostly clear early, with increasing clouds overnight. Lows in the middle 20s. Light west winds.
Friday: Morning snow and possible rain, becoming widespread rain and snow during the afternoon. Highs in the middle 30s. Southeast winds 5-10 mph. Precipitation probability near 100%, with light snow accumulation possible.
Friday Night: Snow and rain continuing, with accumulating snow possible. Lows in the upper 20s. Precipitation probability near 100%.
Saturday: Mostly cloudy, cold, and windy, with scattered snow showers. Highs in the middle 30s. Northwest wind gusts approaching 40 mph. Snow probability 40%.
Saturday Night: A 30% chance of evening snow showers, followed by clearing skies. Lows in the lower 20s.
Sunday: Mostly sunny and chilly. Highs in the upper 30s.
Sunday Night: Mostly clear early, becoming partly cloudy overnight. Lows in the lower 20s.
Monday: Partly sunny early, becoming mostly cloudy. Highs around 50 degrees F.
Monday Night: Mostly cloudy. Lows in the lower 30s.
Tuesday: Partly sunny and milder. Highs in the lower 50s.
Tuesday Night: Partly cloudy. Lows in the lower 30s.
Weather Notice: The weekly forecast, by UMFK Professor Joseph E. Becker, is based on available computer models and data and may not reflect current conditions or later forecast updates. Check The County.me or the National Weather Service Caribou, Maine for the most recent weather information for the Saint John Valley.
