Apex Wx

Overview: The strong nor’easter south of New England will remain the dominant regional weather feature through Monday, while high pressure centered across Quebec continues to feed relatively dry air into northern Maine. This pattern will keep the Saint John Valley on the far northern fringe of the storm through the weekend, with significant rain and the strongest winds remaining well south of the County.

Saturday should remain unusually mild for late September despite periods of cloud cover, with temperatures around 70°F or somewhat warmer. Sunday stays mainly dry as well, although northeast winds become somewhat more noticeable as the pressure difference between the Quebec high and coastal storm strengthens. Temperatures will ease into the mid- to upper 60s.

The pattern begins changing Sunday night into Monday as the coastal low edges north and northeast while gradually weakening. Moisture wrapping around the system should finally reach farther into Aroostook County, bringing thicker clouds and an increasing chance of showers. The additional cloud cover and moisture will also limit daytime warming Monday, with temperatures falling back toward the lower 60s.

Saturday: A mix of sun and clouds should develop through the day, but the SJV remains comfortably north of the nor’easter’s rainfall. It will be another unusually mild late-September afternoon, with highs in the lower 70s and light northeast winds. Clouds remain fairly extensive Saturday night, with lows in the upper 40s.

Sunday: The Valley stays on the northern fringe of the coastal storm, allowing another mainly dry day with variable cloud cover. Northeast winds become somewhat more noticeable during the afternoon as highs reach the mid- to upper 60s to around 70°F. Sunday night turns cooler, with lows around the lower 40s, while clouds begin increasing ahead of a more unsettled Monday.

Monday: The coastal system finally exerts more influence on northern Maine as moisture spreads farther north. Mostly cloudy skies and a chance of showers will make for a cooler day, with highs around the lower 60s. Clouds and occasional shower chances persist Monday night, with temperatures holding in the mid-40s.

Tuesday, September 29 – Friday, October 2

Overview: The slow-moving nor’easter affecting Maine through Monday should finally weaken and pull northeast Tuesday. Moisture wrapping around the departing system will keep northern Maine cloudy, with lingering showers most likely early before precipitation gradually diminishes. Considerable low-level moisture may keep clouds stubborn across the Saint John Valley even after the steadier showers end, holding temperatures near 60°F.

Weak high pressure and shortwave ridging then build across the region Wednesday, beginning a transition toward drier and noticeably milder weather. Increasing sunshine and better daytime mixing should allow temperatures to rebound into the mid- to upper 60s. Thursday appears to be the mildest and quietest day of the period, with temperatures reaching the upper 60s to around 70°F as the SJV remains briefly between weather systems.

The pattern becomes somewhat more unsettled again late Thursday into Friday as another disturbance approaches from the west. Clouds will increase and scattered showers become possible across the County, although current guidance does not indicate a significant rainfall event. Temperatures should remain relatively mild despite the increasing cloud cover.

Tuesday: Showers associated with the departing coastal system should be most numerous early, then gradually diminish as the day progresses. Considerable cloud cover will linger, holding highs around the upper 50s to near 60°F. Tuesday night remains mostly cloudy, with only a slight chance of an early shower and lows in the mid-40s.

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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