Apex Wx

Overview: The coastal low that has been affecting the Mid-Atlantic and Northeast will begin lifting northward toward southern New England and the Gulf of Maine as the blocking high over Quebec gradually weakens. This shift will allow Atlantic moisture to finally reach farther into northern Maine, bringing increasing clouds and a period of rain to the Upper Saint John Valley Monday. While the storm has produced significant impacts closer to the coast, the Valley will remain on the northern edge of its influence, with lighter rainfall and weaker winds. Less than 0.10 inch of rainfall is currently expected across the Valley.

The system gradually pulls away Tuesday as it accelerates toward the Canadian Maritimes. Lingering low-level moisture may keep clouds and a few showers around early in the day, but improving conditions should spread into the Valley later Tuesday. By Wednesday, weak high pressure and upper-level ridging begin rebuilding across northern Maine, bringing a return to drier weather, increasing sunshine, and warmer temperatures. Overall, the period marks a transition from the unsettled conditions of the coastal storm to a quieter and milder pattern.

Monday: Clouds will thicken today as Atlantic moisture reaches northern Aroostook County. Rain becomes increasingly likely through the day, especially during the afternoon and continuing into Monday night. Temperatures remain cooler, with highs around the lower 60s. Northeast winds remain noticeable but gradually ease. Cloudy and damp conditions continue Monday night with lows in the lower to mid-40s.

Tuesday: Lingering morning showers gradually diminish as the coastal low pulls northeast toward Nova Scotia. Considerable cloud cover may persist into the afternoon, but some breaks are possible later in the day. Highs remain in the lower 60s. Tuesday night becomes quieter with partial clearing and cooler conditions, with lows in the upper 30s to lower 40s.

Wednesday: High pressure and upper-level ridging return behind the departing storm, allowing a drier and milder day across the Valley. Any lingering morning clouds should give way to increasing sunshine, with highs rising into the upper 60s to around 70°F. Wednesday night becomes partly to mostly cloudy again, with lows in the upper 40s to near 50°F.

Thursday, October 1 – Sunday, October 4

Overview: The coastal low that has been affecting the Mid-Atlantic and Northeast will begin lifting northward toward southern New England and the Gulf of Maine as the blocking high over Quebec gradually weakens. This shift will allow Atlantic moisture to finally reach farther into northern Maine, bringing increasing clouds and a period of rain to the Upper Saint John Valley Monday. While the storm has produced significant impacts closer to the coast, the Valley will remain on the northern edge of its influence, with lighter rainfall and weaker winds.

The system gradually pulls away Tuesday as it accelerates toward the Canadian Maritimes. Lingering low-level moisture may keep clouds and a few showers around early in the day, but improving conditions should spread into the Valley later Tuesday. By Wednesday, weak high pressure and upper-level ridging begin rebuilding across northern Maine, bringing a return to drier weather, increasing sunshine, and warmer temperatures. Overall, the period marks a transition from the unsettled conditions of the coastal storm to a quieter and milder pattern.

Thursday: High pressure and upper-level ridging bring a return to quieter weather across the Saint John Valley. Any lingering morning clouds should give way to increasing sunshine, allowing temperatures to rise into the lower 70s with light southwest winds. Thursday night becomes partly to mostly cloudy as the next disturbance approaches, with lows in the lower to middle 50s.

Friday: The next disturbance and weak cold front cross northern Maine, but limited moisture should keep shower coverage scattered. Expect a mix of clouds and some breaks of sunshine, with highs in the lower to mid-60s. A wind shift to the northwest brings cooler air Friday night, with mostly cloudy skies, a slight chance of showers, and lows in the upper 30s to around 40°F.

Saturday: Cooler Canadian air settles into the Valley behind the front. High pressure should provide mainly dry conditions with a mix of sun and clouds, although temperatures will be noticeably cooler, with highs in the mid- to upper 50s. Saturday night turns chilly with lighter winds and partly cloudy skies, allowing lows to fall into the lower to mid-30s in sheltered locations.

Sunday: Another mainly dry day is expected as high pressure gradually shifts east, though clouds should increase ahead of the next disturbance. Temperatures remain seasonable, with highs in the mid- to upper 50s. Sunday night becomes mostly cloudy with a 30% chance of rain showers later in the evening, as the approaching system begins to influence northern Maine. Lows should fall into the upper 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.

How accurate are forecasts?

Forecast confidence generally decreases as lead time increases. Forecasts for the next few days usually provide considerably more detail and confidence than forecasts a week or more in advance. Beyond about 7 days, forecasts are most useful for identifying broader weather patterns and temperature or precipitation trends rather than predicting exact conditions at a particular place and time.

Individual computer-model runs—especially those depicting specific storms, snowfall amounts, or other details a week or more in advance—should not be treated as forecasts by themselves. Extended forecasts will change as new observations become available and models better resolve the evolving atmospheric pattern. Check updated forecasts as the event approaches.

Weather Apps

Most weather apps rely heavily on automated forecast data. They can be useful for a quick look at routine weather, but automated forecasts may miss important local details or the significance of rapidly changing conditions. During hazardous or changing weather, consult weather.gov and other official National Weather Service information rather than relying solely on an app.

Radar Apps

Weather radar is an invaluable tool for tracking precipitation and storms, but radar images should not be interpreted as a real-time picture of conditions at the ground. Data collection, processing, transmission, mosaicking, and app updates can introduce delays, and radar detects energy returned from precipitation at varying heights above the surface. During rapidly developing or moving storms, conditions at your location may therefore differ from what a radar app appears to show. Use radar together with current observations and official National Weather Service warnings.