Weather for New England and the Northeast

**Area Forecast Discussion, National Weather Service Gray ME**
**607 AM EDT Wednesday,
September 23, 2026**

**What has changed**

No major changes were needed with the early morning update. A chilly morning in the foothills developed as expected, with Fryeburg reaching the freezing mark. The Frost Advisory will expire on schedule at 7 AM.

The Aviation Discussion was also updated for the 12Z TAFs. TAFs, or Terminal Aerodrome Forecasts, are airport weather forecasts used to describe expected conditions at and around airports.

**Key Messages**

1. Strong high pressure will remain in place through Thursday. Areas of frost will be possible in the foothills during the overnight hours.

2. A strong coastal storm will track near southern New England toward the end of the week. Soaking rain, gusty winds, high surf, and coastal flooding are possible through the weekend.

**Discussion**

**Key Message 1, high pressure and frost**

A seasonably strong area of high pressure is expected to remain across southern Quebec through at least Thursday. The high will continue strengthening and building south through Thursday morning, while temperatures several thousand feet above the ground warm slightly Thursday as the high begins to weaken.

Overall, this morning has the potential to be the coldest morning of the stretch, although tonight could be nearly as cold. Areas of frost will again be possible in the foothills and in other traditionally colder locations.

Valley fog will also be possible on mostly clear nights, especially in areas where the ground cools rapidly under clear skies.

**Key Message 2, coastal storm**

By Friday, a coastal storm will be organizing and strengthening as it slowly moves north toward the vicinity of the 40N/70W benchmark, roughly 40 degrees north latitude and 70 degrees west longitude. Forecast guidance shows the storm stalling or possibly looping south of southern New England before eventually moving east.

This setup could produce a prolonged period of weather impacts across the region. The potential impacts are discussed below, starting with those having the greatest forecast confidence.

**High surf**

A long-lasting northeast wind over a long stretch of open water will allow seas to build through at least the first half of the weekend. Seas reaching around 10 feet appear likely, while significant wave heights of 15 to 20 feet are possible if the storm tracks closer and becomes stronger.

If that occurs, a High Surf Advisory may be needed to highlight the danger from large breaking waves near the shoreline.

**Winds**

A strong difference in air pressure is expected to develop between the coastal storm and the retreating high pressure. Northeast winds also tend to keep the lower atmosphere well mixed because colder air is moving across the region. As a result, gusty winds are expected regardless of the exact storm track.

Even the weaker forecast scenarios are showing 24 to 48 hours of wind gusts around 30 to 35 mph along the coast, especially from Casco Bay southward. As the strongest part of the storm circulation reaches the region Saturday into Sunday, gusts could become even higher if the storm tracks closer to Cape Cod.

A Wind Advisory may eventually be needed for parts of the area.

**Coastal flooding**

Several days of sustained northeast winds and building seas could maximize the potential for storm surge by the weekend. Fortunately, astronomical tides will not reach their highest levels until next week, although tides will be increasing through the weekend.

Some forecast guidance is already indicating that storm surge could reach around 2 feet. That would bring some locations close to flood stage, particularly Saturday night and Sunday around midday. This will need to be monitored closely as the storm approaches.

**Rainfall**

Rainfall amounts will depend heavily on the storm track. The farther west the center of the storm loops and the longer it remains near Cape Cod, the greater the chance for widespread soaking rain.

The ECMWF ensemble forecast is currently more supportive of a wetter storm track, while the GEFS ensemble continues to show plenty of scenarios that keep the storm farther away. Both ensemble systems, however, show a 40 to 60 percent chance of more than 2 inches of total precipitation from Portland southward through the weekend.

The main reason confidence is not higher is the uncertainty in timing. Rain could be most likely anytime from Saturday through Monday, depending on which forecast model or ensemble scenario verifies.

Precipitation amounts will decrease fairly quickly northwest of the storm, so much of the mountains and areas farther north are still expected to remain relatively dry through the event.

Given the strength of the storm and the amount of warm-season moisture still available, there is some concern that the storm could produce locally significant rainfall if the track develops in the right position.

For now, the forecast calls for a manageable soaking rain, but coastal areas from south of Cape Elizabeth to the Massachusetts border are being watched closely. A reasonable worst-case scenario, currently around a 10 percent possibility, would involve rainfall approaching 4 inches.