Apex Wx

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Tuesday, October 13 – Thursday, October 15

Overview: The cold, relatively quiet conditions that began the week will give way to a wetter pattern as low pressure and an associated upper-level disturbance approach northern Maine Tuesday. Increasing easterly and southeasterly flow will transport Atlantic moisture into the region, with rain developing late in the afternoon and becoming widespread Tuesday night. Temperatures near freezing will support a mixture of rain and snow overnight, particularly across the higher terrain of northern Aroostook County. Despite the wintry precipitation, significant snow accumulation is not currently indicated for the Saint John Valley.

The low-pressure system will continue across the region Wednesday, bringing additional rainfall before precipitation becomes more intermittent during the afternoon. Combined liquid precipitation through Wednesday may approach or exceed an inch in some locations. Persistent low-level moisture will maintain extensive cloud cover, while patchy fog may develop in sheltered valleys.

As the system departs Wednesday night, winds will shift northwest and strengthen, introducing a cooler, drier Canadian air mass. Thursday will feature increasing sunshine but brisk northwest winds, with gusts approaching 30 mph. Clearing skies and diminishing winds Thursday night will allow temperatures to fall below freezing across the Valley.

Tuesday: Mostly cloudy skies will persist as temperatures gradually climb into the lower 40s. A 40% chance of rain will develop after 3 p.m., with daytime rainfall generally less than 0.10 inch. Light easterly winds will gradually increase during the afternoon. Rain will become likely early Tuesday evening before transitioning to a mixture of rain and snow after 9 p.m. Precipitation is virtually certain overnight, with a 100% probability and approximately 0.50–0.75 inch of liquid precipitation expected. Southeast winds will increase to 7–10 mph, with temperatures falling into the middle 30s.

Wednesday: Rain will continue through the morning before becoming more intermittent during the afternoon. The precipitation probability is 100%, with an additional 0.25–0.50 inch expected. Cloudy skies will persist, with temperatures reaching the middle 40s. Easterly winds of 3–10 mph will gradually shift as low pressure moves away. Wednesday night will remain mostly cloudy, with a slight chance (20%) of lingering rain showers and temperatures falling into the upper 30s. Northwest winds will increase to 5–16 mph, with occasional gusts approaching 25 mph.

Thursday: Improving conditions are expected as drier Canadian air spreads into northern Maine. Skies will become mostly sunny, although temperatures will remain cool, with afternoon highs in the middle 40s. Northwest winds of 13–17 mph, gusting to around 30 mph, will maintain a brisk feel throughout the day. Winds will gradually diminish Thursday evening as skies become partly cloudy. Overnight temperatures will fall into the upper 20s, bringing another widespread freeze to the Saint John Valley.

Friday, October 16 – Monday, October 19

Overview: The brief return to drier weather Thursday will give way to another unsettled period as low pressure approaches the Valley from the Great Lakes and southern Canada Friday. Increasing southeasterly flow will transport moisture into the region, with precipitation developing during the morning. Following Thursday night's freeze, precipitation may begin as snow before mixing with or changing to rain as temperatures approach 40°F. Rain and snow will continue Friday night, with accumulating snow possible, particularly across the higher terrain of northern Aroostook County. Snowfall amounts remain uncertain because of marginal temperatures and the timing of the transition between precipitation types.

As the system moves east Saturday, colder air circulating around the departing low will support lingering snow showers, although precipitation should become lighter and more scattered. Temperatures near 40°F will limit daytime accumulation in the Saint John Valley, while decreasing precipitation and overnight cooling may allow wet surfaces to refreeze Saturday night.

High pressure will gradually build into northern New England Sunday, bringing drier conditions and increasing sunshine. Clearer skies and lighter winds will favor another cold night, particularly in sheltered valleys. By Monday, a moderating air mass will allow temperatures to recover into the upper 40s, with increasing clouds possible overnight ahead of the next disturbance.

Friday: Increasing clouds will precede another round of precipitation beginning after 9 a.m. Snow may develop initially before mixing with or changing to rain as temperatures climb toward 40°F. The precipitation probability is 90%, with light southeasterly winds accompanying the approaching system. Rain will continue Friday evening before mixing with snow after approximately 2 a.m. Precipitation remains likely overnight, with an 80% probability and temperatures falling into the lower 30s. Some snow accumulation is possible, although amounts remain uncertain.

Saturday: Mostly cloudy skies will persist as the departing system leaves scattered snow showers across northern Aroostook County. The precipitation probability is 30%, with temperatures reaching around 40°F. Any remaining snow showers should generally be light, with limited accumulation expected at lower elevations during the afternoon. Mostly cloudy conditions will continue Saturday evening, with a 30% chance of lingering snow before midnight. Temperatures will fall into the middle 20s overnight as colder air becomes established across the Valley.

Sunday: Drier air and building high pressure will bring a return to mostly sunny skies across the Saint John Valley. Afternoon temperatures will reach around 40°F, maintaining the cool conditions that have characterized much of the period. The absence of significant precipitation and increasing sunshine will provide an improvement following Friday's and Saturday's unsettled weather. Skies will remain partly cloudy Sunday night, with temperatures falling into the middle 20s as radiational cooling becomes more effective.

Monday: Mostly sunny skies and a moderating air mass will allow temperatures to recover into the upper 40s, making this the mildest day of the forecast period. Dry conditions will prevail as high pressure maintains its influence across northern Maine. Clouds will gradually increase Monday evening and overnight as the next weather system approaches from the west. The additional cloud cover should limit cooling compared with previous nights, with temperatures falling into the lower 30s.

Long Range Trends: Tuesday, October 20 – Monday, October 26

The latest long range outlook favors above-normal precipitation across northern Maine, while the Saint John Valley lies near the boundary between near- and below-normal temperature tendencies. Ridging across eastern North America may encourage some moderation, although the evolving pattern leaves uncertainty in northern Maine's temperature outlook. Seasonal averages feature daytime highs in the upper 40s to around 50°F and overnight lows near 30°F. The precipitation outlook suggests a continued tendency toward unsettled weather.

Outlooks updated 7-9 AM weekdays & 8-10 AM weekends and holidays. Long range outlooks indicate broader temperature and precipitation trends rather than precise day-to-day forecasts. Common abbreviations: NWS = National Weather Service; WPC = Weather Prediction Center; SPC = Storm Prediction Center; CPC = Climate Prediction Center, NHC = National Hurricane Center

Updated every 3-6 hours from NWS Caribou

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.