Weather for New England and the Northeast

Area Forecast Discussion
National Weather Service Gray ME
241 AM EDT Thursday, June 18, 2026

**What Has Changed**

A Flash Flood Watch has been issued for the mountains and foothills for today.

**Key Messages**

1. An unseasonably strong storm is forecast to cross the region Thursday, leading to a chance of both severe thunderstorms and heavy rainfall.

2. The weather pattern remains unsettled Friday through the weekend with daily chances for afternoon showers and a few storms.

3. Low pressure could bring more widespread rainfall early next week.

**Synopsis**

An unusually strong storm system for this time of year will move into the region from the west today. Widespread rainfall is expected to increase this morning, with the heaviest precipitation likely during the afternoon.

Forecast precipitation totals have been increased across the mountains due to a very strong low-level jet stream, a corridor of fast-moving winds a few thousand feet above the ground, combined with unusually high atmospheric moisture levels. Forecasters also incorporated high-resolution weather models, including the HREF (High-Resolution Ensemble Forecast) and HRRR (High-Resolution Rapid Refresh), which are better at identifying smaller-scale weather features and localized areas of heavier precipitation.

Because parts of the region have experienced flooding during the past one to two weeks, and because streams and drainage systems can respond quickly to heavy rainfall, a Flash Flood Watch has been issued for the mountains and foothills.

In addition to the flooding threat, a few strong to severe thunderstorms may develop this afternoon after the main area of rain moves through. Atmospheric instability is expected to be somewhat limited. However, even modest instability combined with unusually strong wind shear, changes in wind speed and direction with height, could support a few rotating thunderstorms and isolated damaging wind events.

Outside of thunderstorms, wind gusts could reach 30 mph today due to the strong low-level jet.

Drier air arrives tonight behind the storm system, although upslope rain showers may linger across the mountains.

**Key Message 2 Description**

Forecast guidance continues to show a broad area of low pressure circulating over eastern Canada through the weekend, maintaining an unsettled weather pattern across the region.

A vertically stacked low-pressure system, meaning the storm remains aligned through multiple levels of the atmosphere, will move north of the area Friday and into the Canadian Maritimes on Saturday. Smaller disturbances rotating around the larger system will help trigger afternoon showers and thunderstorms both days, especially across the mountains and foothills.

Forecast soundings suggest freezing levels will be low enough to support small hail in stronger storms. Winds around 5,000 feet above the ground could range from 25 to 35 mph, with some of that momentum potentially reaching the surface in heavier showers and storms.

Temperatures will remain near seasonal averages, generally reaching the middle to upper 70s south of the mountains, while northern areas remain cooler in the 60s due to more persistent cloud cover. Overall, conditions should be fairly pleasant between periods of unsettled weather.

By Sunday, the upper-level storm system begins weakening and stretching into a broader trough. Afternoon showers and thunderstorms remain possible, but wind gusts should be noticeably lighter.

One additional item being monitored is the potential redevelopment of the remnants of Tropical Cyclone Arthur off the Mid-Atlantic coast. Current forecast guidance keeps any redevelopment well offshore and away from New England. However, it could still contribute to higher wave heights and an increased rip current risk along the coastline.

**Key Message 3 Description**

Forecast models continue to indicate another upper-level low-pressure system may move into the region early next week, bringing the next opportunity for widespread rainfall.

While confidence is increasing that another storm system will affect the area, there remains considerable uncertainty regarding timing and strength. Most forecast ensembles favor a coastal storm track, but solutions vary significantly.

The GFS model remains the fastest solution, bringing rainfall into the region Sunday night and moving the storm through by Monday. The European model is slower, delaying the storm until Monday night and moving it up the coast on Tuesday. The Canadian model generally agrees with the European timing but depicts a weaker storm system.

This period will be important to monitor because coastal storm systems can sometimes produce enhanced rainfall totals. At this time, however, confidence remains low regarding exact timing and impacts.

Most forecast guidance suggests conditions trend drier by the middle of next week as an upper-level ridge of high pressure builds into the eastern United States.