Wednesday-Friday
A transition from relatively mild autumn weather to colder and breezier conditions will unfold across the St. John Valley during the second half of the workweek. An elongated area of high pressure over the eastern United States will maintain generally sunny skies Wednesday, with afternoon temperatures reaching the lower 50s. Light winds and abundant sunshine will provide a pleasant October day from Fort Kent through Van Buren.
Mostly clear skies Wednesday night will allow temperatures to fall into the upper 20s. The combination of light winds and nighttime cooling may also produce patchy fog toward daybreak Thursday, particularly in sheltered sections of the Saint John and Fish River valleys.
The weather pattern will begin changing Thursday as a disturbance passing through eastern Canada brings stronger northwest winds and another push of colder Canadian air into northern Maine. Any early morning fog should dissipate quickly, with sunshine returning during the day. However, northwest winds of 10-15 mph, occasionally gusting to around 25 mph, will make afternoon temperatures in the upper 40s feel noticeably cooler. Breezy conditions will continue Thursday night as temperatures fall below freezing.
By Friday, the colder air mass will become firmly established across the Valley. Sunshine will continue, but persistent northerly winds will keep afternoon temperatures in the lower 40s. Gusts approaching 25 mph will add to the chill, particularly across exposed terrain. Winds will gradually diminish Friday evening as high pressure rebuilds, allowing temperatures to fall into the lower 20s overnight under clear skies.
Saturday-Tuesday
The weekend will bring a temporary warming trend across northern Maine as high pressure maintains generally dry and settled conditions. Saturday will feature abundant sunshine and lighter winds, with afternoon temperatures recovering into the lower 50s. Following Friday’s chilly conditions, the improvement should provide favorable weather for outdoor activities. Clear skies Saturday night will allow temperatures to fall to around freezing, with locally colder readings possible in sheltered valley locations.
Sunday will be the warmest day of the seven-day period, with sunshine and afternoon temperatures reaching the middle to upper 50s. However, the settled pattern will begin changing Sunday night as an approaching disturbance brings increasing clouds and a slight chance of light rain toward Monday morning. Rainfall should remain limited, with temperatures staying relatively mild overnight.
Any lingering light rain should end early Monday, followed by partly sunny skies and afternoon temperatures around 50. Colder Canadian air will begin advancing into northern Maine later Monday, bringing another noticeable change in the weather.
By Tuesday, temperatures are expected to fall considerably, with afternoon highs reaching only the upper 30s despite intervals of sunshine. This sharp cooling will mark a return to more typical late-autumn conditions, with overnight temperatures falling into the lower to middle 20s. The precise strength and timing of the colder air’s arrival remain somewhat uncertain, although the broader cooling trend appears well established.
Looking Ahead: October 28-November 3
The Climate Prediction Center’s outlook indicates near-normal temperatures across the region, with below-normal precipitation favored for the Saint John Valley. A broad area of high pressure aloft over eastern North America may help limit storm activity, although the temperature outlook does not strongly favor either warmer or colder conditions. Typical temperatures for this time of year include daytime highs in the lower to middle 40s and overnight lows in the middle 20s to around 30.
Daily Forecast Summary
Wednesday: Sunny, with highs in the lower 50s. Light and variable winds.
Wednesday Night: Clear, with patchy valley fog developing after midnight. Lows in the upper 20s. Southwest winds around 5 mph.
Thursday: Partly sunny, with highs in the upper 40s. Northwest winds increasing to 10-15 mph, with gusts around 25 mph.
Thursday Night: Partly cloudy early, becoming mostly clear. Lows in the upper 20s. North winds 10-15 mph, gusting to 25 mph.
Friday: Mostly sunny and chilly, with highs in the lower 40s. North winds 10-15 mph, with gusts around 25 mph.
Friday Night: Clear and cold, with lows in the lower 20s.
Saturday: Sunny and milder, with highs in the lower 50s.
Saturday Night: Clear, with lows in the lower 30s.
Sunday: Mostly sunny, with highs in the middle 50s.
Sunday Night: Partly cloudy, with lows around 40. A 20% chance of light rain toward morning.
Monday: Partly sunny, with highs around 50. A 20% chance of light rain early.
Monday Night: Partly cloudy and colder, with lows in the upper 20s.
Tuesday: Partly sunny and considerably colder, with highs in the upper 30s.
Tuesday Night: Partly cloudy, with lows in the lower to middle 20s.
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.
