Weather for New England and the Northeast

**Area Forecast Discussion, National Weather Service Boston/Norton MA,
302 PM EDT Fri Sep 18 2026**

**What has Changed**

Small Craft Advisories have been issued for many area waters tonight into Saturday morning. These advisories mean that winds and waves may create hazardous conditions for smaller boats.

**Key Messages**

1. Dry with fall-like weather tonight through Saturday night. Lows both nights will mainly be in the 40s to lower 50s. Highs Saturday will mainly be in the 60s, with temperatures possibly reaching 70 degrees in the lower Connecticut River Valley.

2. The next chance for rain is Sunday into Monday. There remains uncertainty regarding coverage, timing, and rainfall amounts. Showers may linger into early next week. A coastal low pressure system is possible late next week.

**Discussion**

**Key Message 1, Dry with fall-like weather tonight through Saturday night**

A very pleasant fall-like air mass is expected across the region tonight through Saturday night. This will occur as high pressure builds eastward across Quebec tonight and then into northern New England and the Canadian Maritimes Saturday into Saturday night. High pressure is an area of sinking air that generally brings more stable and dry weather.

Drier and cooler air will move into the region tonight. Winds should weaken enough overnight to allow temperatures to fall into the 40s across many locations. Some urban areas, as well as Cape Cod and the Islands, should remain in the lower to middle 50s because a steady north wind will prevent temperatures from dropping as much.

Saturday should feature plenty of sunshine, but a cool northeast flow will keep high temperatures mainly in the 60s. Temperatures may approach 70 degrees in parts of the lower Connecticut River Valley. The coolest temperatures will be along the immediate eastern Massachusetts coast, Cape Cod, and the Islands, where highs will remain in the lower to middle 60s.

High pressure will slowly move east of the region Saturday night. There should still be enough of a window for good radiational cooling before thicker clouds move in toward daybreak. Radiational cooling occurs when the ground loses heat quickly under relatively clear and calm conditions. Low temperatures should fall well into the 40s in most locations, with lower 50s expected in the urban heat island of Boston, where buildings and pavement tend to retain more heat.

**Key Message 2, Next chance for rain Sunday into Monday**

The latest forecast guidance continues to suggest widespread rainfall later Sunday into Monday morning. This does not appear to be an especially strong or dynamic storm system, but a wetting rain should spread across southern New England from west to east during the day Sunday. The most likely period for steady rainfall appears to be Sunday night.

The main question then becomes how quickly a front moves south of the region Monday morning. A front is the boundary separating different air masses and can often bring changes in temperature, wind, clouds, and precipitation.

At this time, dry weather is favored for most of Monday, continuing through Wednesday. Some individual forecast models suggest the front could remain slightly farther north, which would allow a small chance for continued precipitation near the south coast. Given the strength of the high pressure system over eastern Canada, that solution is currently being given less weight.

**Late Next Week**

Forecast guidance is hinting at a possible coastal low pressure system sometime Thursday into Friday. However, there are large differences among the forecast models regarding both timing and track.

For example, the **8 AM EDT GFS** forecast model places a low pressure center over the Gulf of Maine at 8 AM EDT next Friday. Meanwhile, the **8 AM EDT ECMWF** model places the same low pressure system about 300 miles east of southern Maryland at that time. These different positions would result in very different storm tracks because of interactions with a mid-level trough, which is an elongated area of lower pressure in the middle levels of the atmosphere.

At this time, confidence is low regarding the details of the late next week forecast. The potential coastal system will need to be monitored as new forecast information becomes available.