Weather for New England and the Northeast

Area Forecast Discussion, National Weather Service Gray ME
**626 AM EDT, Sunday, July 12, 2026**

**What Has Changed**

No significant changes were made to the forecast at this time.

**Key Messages**

1. High pressure brings mostly dry weather and seasonably warm temperatures with comfortable humidity through today.

2. Hot and humid conditions bring Moderate to Major Heat Risk Monday through Wednesday, with the peak occurring on Tuesday. Humidity decreases during the second half of the week while temperatures continue to run above normal.

3. A cold front brings the threat for severe storms late Tuesday into Tuesday night.

**Discussion**

**Key Message 1 Description**

Pleasant summer weather will continue today as high pressure remains over New England. Expect mostly sunny skies with afternoon temperatures reaching the lower to middle 80s. Light winds will allow a sea breeze to develop early in the afternoon, gradually moving farther inland through the afternoon and early evening.

Clear to partly cloudy skies tonight will allow temperatures to cool efficiently after sunset, a process known as radiational cooling. Overnight lows will fall into the upper 40s across the northern valleys and the middle to upper 50s elsewhere. Areas of valley fog are once again possible by early Monday morning.

**Key Message 2 Description**

A large ridge of high pressure in the upper atmosphere over the central United States will expand eastward Monday into Tuesday, bringing much hotter air into New England. Temperatures several thousand feet above the ground will become unusually warm, supporting afternoon highs in the lower to middle 90s Monday and the middle to upper 90s Tuesday.

Humidity will remain fairly comfortable Monday, with dew points generally in the 50s to lower 60s. By Tuesday, moisture levels increase with dew points rising into the middle and upper 60s. This combination of heat and humidity will push the heat index close to 100 degrees during the afternoon. Heat Advisories will likely be needed for parts of the region.

Tuesday night will provide little relief, with overnight temperatures remaining in the 70s. Warm nights like this increase cumulative heat stress because the body has less opportunity to cool down.

A colder front moves through Wednesday, bringing a drier air mass and noticeably more comfortable humidity for the rest of the week, although temperatures will continue to remain above average.

**Key Message 3 Description**

A strong upper level storm system will move across Quebec on Tuesday while a deep area of low pressure develops at the surface. Ahead of an approaching cold front, conditions may become favorable for severe thunderstorms across New England Tuesday afternoon and evening.

One important feature meteorologists are watching is an Elevated Mixed Layer (EML), a layer of very warm, dry air several thousand feet above the ground that can increase atmospheric instability. Forecasts also indicate steep lapse rates, meaning temperatures decrease rapidly with height, another ingredient that helps thunderstorms strengthen.

Combined with very warm surface temperatures and dew points rising into the upper 60s and lower 70s, the atmosphere is expected to become highly unstable. Forecast Most Unstable Convective Available Potential Energy (MUCAPE), a measure of the fuel available for thunderstorms, may reach 2000 to 3000 joules per kilogram, an unusually high value for July.

At the same time, winds at different heights in the atmosphere are expected to vary significantly in both speed and direction. Forecast bulk wind shear of 45 to 60 knots and Storm Relative Helicity (SRH), a measure of the atmosphere ability to help thunderstorms rotate, indicate an environment that could support organized, long lasting severe thunderstorms capable of producing damaging wind gusts, large hail, torrential rainfall, and possibly isolated tornadoes.

The greatest uncertainty remains the timing and coverage of any storms. Thunderstorms are expected to develop first well north of New England during the afternoon. If they move into northern New England, they would most likely arrive during the evening after daytime heating has begun to fade.

Normally, thunderstorms weaken after sunset. However, the combination of an Elevated Mixed Layer (EML) and unusually strong wind shear could allow storms to remain strong much later into the night than is typical.

Forecast confidence is still limited because higher resolution short range forecast models have not yet come into their most useful range. There is still a possibility that the upper level system slows enough to keep most of the severe weather in Canada. If the system moves faster, severe thunderstorms could affect a much larger portion of New England.

The Storm Prediction Center continues to highlight areas north of a line from Concord, New Hampshire, to Portland, Maine, to Rockland, Maine, with a 15 percent chance of severe thunderstorms.