Apex Wx

Overview:  High pressure shifting east of Maine will give way to increasingly unsettled weather Wednesday as south to southwest flow brings more clouds and moisture into northern Maine. Scattered light rain develops during the afternoon and becomes more widespread Wednesday night. The southerly flow will also produce a milder night, with temperatures remaining in the lower to middle 40s.

A cold front associated with low pressure northwest of the region crosses northern Maine Thursday, bringing the best opportunity for rainfall. Showers will become likely, with generally 0.10–0.25 inch expected near Fort Kent. Weak afternoon instability may also support an isolated thunderstorm, with small hail possible in a stronger shower, although severe weather is not expected. Temperatures moderate into the upper 50s ahead of the front.

Cooler and drier west to northwest flow develops behind the front Thursday night into Friday. An upper-level trough lingering across the region will maintain enough moisture and instability for scattered showers Friday, while west winds become breezy with occasional gusts around 25 mph. Highs fall back into the lower 50s before high pressure becomes more influential Friday night, allowing temperatures to fall into the lower 30s with renewed frost potential.

Wednesday: Widespread morning frost will give way to mostly cloudy skies. A 20% chance of light rain develops after mid-morning, with the better opportunity during the afternoon. Highs will reach the lower to middle 50s. Light southwest winds will become south around 5–10 mph, with occasional gusts near 20 mph. Tonight will remain mostly cloudy with a 40% chance of rain and lows in the lower to middle 40s.

Thursday: Mostly cloudy and milder with showers likely, particularly from late morning through the afternoon. An isolated thunderstorm is possible, with small hail possible in a stronger shower, but severe weather is not expected. The chance of precipitation is around 60%, with generally 0.10–0.25 inch of rain expected. Highs will reach the upper 50s. South winds around 5–10 mph will turn southwest as the front crosses the Valley. Thursday night will remain mostly cloudy but generally dry after any early showers end, with lows in the mid-30s.

Friday: Partly sunny to mostly cloudy, cooler, and breezy beneath the lingering upper-level trough. A 30% chance of showers develops, mainly later in the day. Highs will reach the lower 50s. West winds around 8–14 mph may gust to around 25 mph. Friday night will become partly cloudy with temperatures falling into the lower 30s, bringing renewed frost potential toward Saturday morning.

Saturday, October 10 – Tuesday, October 13

Overview:  Cool west to northwest flow will remain across northern Maine Friday behind the departing frontal system. A weak disturbance and lingering low-level moisture may produce an isolated afternoon or evening shower, but most of the day should remain dry. High pressure then builds into the region Friday night and Saturday, bringing a cooler and increasingly dry Canadian air mass. Highs will reach only the lower 50s Saturday, followed by favorable radiational cooling Saturday night as winds become light. Temperatures should fall around freezing to the lower 30s, with frost likely across the Saint John Valley.

High pressure shifts east Sunday, allowing southerly return flow to develop. After a chilly start, temperatures should rebound into the lower 60s, making Sunday the mildest day of the period. Clouds increase Sunday night as moisture begins returning ahead of the next system, with a slight chance of rain.

The approaching frontal system brings increasingly unsettled conditions Monday. Rain chances rise to around 30%, although timing and coverage remain uncertain at this range. Temperatures should reach the upper 50s to around 60°F before rain chances continue Monday night under mostly cloudy skies, with lows falling into the mid- to upper 30s.

Saturday: Mostly sunny, dry, and seasonably cool as high pressure builds across northern Maine. Highs should reach around 50°F, with northwest winds gradually diminishing. Saturday night will become mostly clear to partly cloudy with lows in the lower 30s. Frost is likely, especially in sheltered portions of the Saint John Valley. 

Sunday: Partly sunny and noticeably milder as southerly return flow develops. Highs should rebound into the lower 60s, with south to southwest winds becoming somewhat breezy. Sunday night will turn increasingly cloudy, with a 40% chance of rain after midnight. Increasing clouds and southerly flow will keep temperatures much milder, with lows in the middle 40s. 

Monday: Partly sunny to mostly cloudy with a 40% chance of rain as the next frontal system approaches northern Maine. Highs should reach around 60°F. Rain remains possible Monday night with a 30% chance of precipitation, followed by partial clearing. Overnight lows fall into the upper 30s. 

Tuesday: Partly sunny with a 40% chance of rain as the system remains influential across northern Maine. Temperatures trend cooler behind the weekend warm-up, with highs in the middle 50s. Rain remains possible Tuesday night under mostly cloudy skies, with a 40% chance of precipitation and lows in the middle 30s.

Weather Notice

Apex Wx forecasts are based on available observations, computer model guidance, and other meteorological data. Conditions and forecast guidance can change, and information displayed here may not reflect the latest official forecast or warning information. Always visit NWS Caribou for the latest official forecasts, watches, warnings, and advisories for northern Maine.

Apex Wx is a private weather information service unaffiliated with NOAA or the National Weather Service and operated by Joseph Becker. Dr. Becker earned a Certificate in Weather Forecasting from Penn State University and is a trained NWS SKYWARN Storm Spotter.

Credits

• Sun and Moon data from the U.S. Naval Observatory, with additional astronomical information from timeanddate.com.
• NOAA warning banner provided by WillyWeather.com.
• Through December 2026, additional archived Apex Wx weather data are available through the University of Utah's MesoWest.
• Current and archived Apex Wx weather data are available through Synoptic Data, the successor to MesoWest.
• Apex Wx logo by Joanna Becker © 2016. Visit Bushi and Brush Arts Dojo.

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