Apex Wx

Overview:  The chilly northwest flow that settled across northern Maine late in the week will continue Saturday as high pressure builds toward the region. Mostly sunny skies will accompany temperatures struggling to reach 50, while gusty northwest winds make conditions feel cooler.

Winds will diminish Saturday evening as high pressure moves closer, allowing temperatures to fall rapidly beneath mostly clear skies. Widespread frost and localized freezing conditions are expected, particularly in the sheltered Saint John and Fish River valleys.

A substantial warm-up arrives Sunday as high pressure shifts east and strengthening southwest flow transports warmer air into the Saint John Valley. After a frosty morning, temperatures should climb into the middle to upper 60s despite increasing clouds and a noticeable southwest breeze. Continued southwest winds and cloud cover Sunday night will limit cooling, keeping temperatures considerably milder than Saturday night.

The warmer weather will be short-lived as a cold front approaches northern Maine Monday. Clouds will increase ahead of the front, with rain developing during the afternoon and becoming more widespread Monday evening and overnight. Temperatures will fall as colder air moves into the region, potentially reaching the middle 30s by Tuesday morning. Rain may begin mixing with snow late Monday night, although accumulating snow is not currently expected in the Valley.

Saturday: High pressure building toward northern Maine will bring a mostly sunny but chilly autumn day. Temperatures should reach the upper 40s to around 50, with northwest winds of 10–15 mph and gusts near 25 mph making conditions feel cooler. Winds diminish this evening as skies remain mostly clear initially, favoring rapid cooling. Widespread frost is expected before clouds increase overnight, with lows around 30 and locally colder temperatures in sheltered valleys.

Sunday: Following a frosty morning, strengthening southwest flow will bring a substantial warm-up to the Saint John Valley. Sunshine should prevail through much of the day, allowing temperatures to reach the middle to lower to mid-60s despite a noticeable southwest breeze, with occasional gusts around 20–25 mph. Clouds increase Sunday night ahead of the next frontal system, but continued southwest winds will keep temperatures considerably milder than Saturday night, with lows in the upper 40s.

Monday: The warm spell will be short-lived as a cold front approaches northern Maine. Some early sunshine should give way to increasing clouds, with temperatures reaching the upper 50s before cooler air begins moving into the region. A 50 percent chance of rain develops mainly during the afternoon, with less than 0.10 inch expected during the day. Rain becomes more likely Monday night, with a 70 percent precipitation chance and an additional 0.10–0.25 inch possible. As temperatures fall into the lower to middle 30s, rain may mix with snow toward daybreak Tuesday.

Tuesday, October 13 – Friday, October 16

Overview: The colder and more unsettled weather arriving late Monday will continue into Tuesday as an upper-level trough settles across the Great Lakes and eastern Canada. Low pressure and associated frontal boundaries will maintain considerable cloudiness and periods of rain across northern Maine. Temperatures near freezing early Tuesday may allow rain to mix briefly with wet snow, particularly across higher terrain. Daytime temperatures should recover into the middle to upper 40s, but precipitation may again mix with snow Tuesday night as readings fall into the lower 30s. Significant snow accumulation is not currently expected in the Saint John Valley.

Conditions should gradually improve Wednesday as the disturbance moves east and drier air spreads into northern Aroostook County. A few early rain or snow showers may linger before clouds begin breaking during the afternoon. High pressure will become more influential Thursday, bringing mostly sunny skies and temperatures around 50. However, the cooler air mass will remain in place, with nighttime temperatures near freezing and frost possible in sheltered valleys.

Another weak disturbance may approach Friday, bringing increasing clouds and a slight chance of rain during the day. Rain chances increase to 50 percent Friday night, with mostly cloudy skies and temperatures falling into 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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