Weather for New England and the Northeast

**Area Forecast Discussion, National Weather Service Gray ME**
**640 AM EDT Tuesday, July 28, 2026**

**What Has Changed**

Update to the Aviation section for the 12 EDT Terminal Aerodrome Forecasts, TAFs.

**Key Messages**

1. The recent dry stretch of weather ends today with increasing chances for slow moving showers and thunderstorms by Tuesday afternoon and evening.

2. A cutoff low develops over the region Tuesday night through Friday, bringing multiple rounds of rainfall with locally heavy rain possible.

3. Some drier weather is expected this weekend with warmer temperatures, but daily chances for precipitation continue, especially Sunday.

**Discussion**

**Key Message 1 Description**

A large upper level trough over Hudson Bay is sending several smaller disturbances, known as shortwaves, toward New England. One stronger disturbance will move into the eastern Great Lakes today and help form a cutoff low pressure system over upstate New York by this evening.

This setup will draw very humid air northward into New Hampshire and western Maine tonight. Atmospheric moisture values, measured by precipitable water, PWAT, are expected to reach between 1.5 and locally over 1.75 inches, which is unusually high for late July and supports efficient rainfall production.

The greatest chance for afternoon and evening thunderstorms will be across New Hampshire, where the combination of moisture and atmospheric lift is strongest. Forecast guidance indicates storms will move slowly, increasing the potential for locally heavy rainfall.

Several technical indicators suggest isolated flash flooding is possible. Forecast models indicate limited storm movement and deep warm cloud layers, both of which favor heavy rainfall. However, because soils remain very dry after the recent stretch of dry weather, the overall flash flood threat remains low today. Today's rainfall is expected to prepare the ground for a greater rainfall event on Wednesday rather than produce widespread flooding by itself.

Clouds will steadily increase through the day, with afternoon temperatures reaching around 80 degrees in most locations.

**Key Message 2 Description**

The cutoff low pressure system will slowly move from upstate New York Wednesday morning, to southern New England Thursday morning, and into the Gulf of Maine by Friday morning.

Wednesday is expected to bring the most significant weather as a surface low pressure system pushes an area of moderate to locally heavy precipitation across the region. Additional rounds of precipitation are likely Thursday as the storm remains nearby. Persistent clouds and precipitation will keep temperatures below normal throughout this period.

On Wednesday, strengthening low level winds will help organize bands of heavier precipitation. While atmospheric instability will be somewhat lower than Tuesday, the environment will still be capable of producing heavy rainfall. Forecast models continue to differ on the exact timing and placement of the heaviest precipitation, but moderate to locally heavy rain appears increasingly likely from late morning through the afternoon.

If multiple areas of heavy precipitation repeatedly move across the same locations, isolated flash flooding could occur. High temperatures will remain mostly in the lower 70s, with some areas staying below 70 degrees because of clouds and rainfall. Showers are expected to continue Wednesday night, and areas of fog are also likely due to the very humid air.

Showers will continue Thursday, although confidence remains lower regarding exactly where the heaviest precipitation will fall. With the upper level low directly overhead, showers may move very slowly. As soils become wetter, the risk of isolated flash flooding may increase if widespread or organized bands of heavy precipitation develop. Northeasterly winds Thursday night should gradually reduce the flooding threat, although scattered showers may linger.

Ensemble forecasts, which combine many model simulations to estimate possible outcomes, indicate the highest probabilities for more than 2 inches of precipitation are across southwestern Maine and New Hampshire, mainly south of the mountains. Flash flood guidance, which estimates how much precipitation is needed before flooding becomes likely, remains above 3 inches over six hours for most of the region and above 4 inches across the New Hampshire Mountains, Lakes Region, and southeastern Maine. This suggests any flash flooding should remain isolated.

River flooding is not expected because rivers and streams have plenty of capacity after a much drier than normal July.

By Friday, the cutoff low weakens and begins moving away. This should allow for more sunshine and somewhat warmer temperatures, although scattered showers will remain possible.

**Key Message 3 Description**

Forecast models are in unusually good agreement regarding the overall weather pattern heading into next week.

Low pressure is expected to gradually lose its influence by Saturday as it weakens offshore. There is still some uncertainty because cutoff low pressure systems are often difficult for weather models to handle accurately, but most guidance points toward Saturday being the drier day of the weekend. Sinking air behind the departing storm system should also help limit shower development.

By Sunday and beyond, another upper level trough is expected to move southeast from Hudson Bay toward New England. Southwesterly winds ahead of that system will bring increasing humidity, and another area of low pressure may develop in the Ohio Valley.

While details remain uncertain this far in advance, confidence is increasing that shower chances will rise again late Sunday, especially across inland areas. The overall expectation is for Saturday to be the more favorable day for outdoor activities, with wetter conditions becoming more likely as the weekend comes to a close.