Weather for New England and the Northeast

**Area Forecast Discussion, National Weather Service Boston/Norton MA, 349 AM EDT Fri Aug 21 2026**

**WHAT HAS CHANGED**

No significant changes to the forecast.

**KEY MESSAGES**

* Cooler than normal temperatures today with steady rain most likely towards eastern MA.

* Wet and unusually cool for the weekend.

* Drier and warmer to start next week.

**DISCUSSION**

**KEY MESSAGE 1, Cooler than normal temperatures today with steady rain most likely towards eastern MA**

Weak low pressure currently centered south of Long Island is expected to slowly shift northeastward today. As it does, eastern Massachusetts, particularly southeastern Massachusetts, Cape Cod, and the Islands, will likely continue to see steadier rain.

A sharp rainfall gradient remains likely across the region. It starts near the northern portion of the South Shore, continues along I-95 toward the Rhode Island border, then follows the northern borders of Rhode Island and Connecticut. Expected rainfall totals decrease from around 0.5 inches near the coast to around 0.3 inches farther northwest, with amounts diminishing farther north.

The NAM, one of the weather forecast models, continues to appear to be an outlier with its rainfall totals. Most other models suggest an additional 0.1 inches or less around Boston and areas north and west, increasing to an additional 0.25 to 0.5 inches across Cape Cod, southeastern Massachusetts, and Rhode Island. The latest HREF PMM, an ensemble forecast method that combines multiple high resolution model forecasts, also keeps the higher rainfall totals focused on southeastern Massachusetts, Cape Cod, the Islands, Rhode Island, and the south coast.

Persistent cloud cover and winds circulating around the low pressure system will keep the region feeling much cooler than normal for late August. High temperatures today will likely reach only the low to mid 70s across eastern areas, with coastal locations possibly remaining cooler. Interior areas should see little additional precipitation, although clouds will remain common. Temperatures may reach the upper 70s, particularly in the Connecticut River Valley.

Rain should become much lighter tonight. Onshore winds will continue, although they may begin turning more northerly as the low moves northeastward. Overnight lows will generally be in the 50s across the interior and the 60s farther east.

**KEY MESSAGE 2, Wet and unusually cool for the weekend**

The low pressure system south of the region will continue tracking northeast into Saturday. Its associated cold front will likely stall near the eastern coastline and could cross Cape Cod. With the front remaining nearby, cloudy skies and onshore winds are expected to continue into Saturday.

Some differences remain among the forecast models regarding the exact location of the low. The overall consensus places it just offshore of Nantucket Saturday morning. The NAM moves the low northeast faster than most other models, while the Canadian model and RAP, the Rapid Refresh model, keep it farther south near Long Island around the same time. The low should continue moving north during Saturday and could reach Downeast Maine by Saturday night.

The overall weather pattern for the weekend remains largely unchanged. A stronger upper-level trough, meaning an elongated area of lower pressure and cooler air aloft, will move closer from the Great Lakes Saturday into Sunday. At the same time, an unusually moist air mass will move into the region. PWAT, or precipitable water, values approaching 2.0 inches indicate a large amount of moisture available for rainfall.

NAEFS, the North American Ensemble Forecast System, shows atmospheric moisture levels up to around two standard deviations above normal. Other forecast guidance also shows favorable IVT, or integrated vapor transport, indicating strong transport of moisture into eastern Massachusetts and Rhode Island this weekend.

Ensemble forecasts show a lower probability of receiving 1 inch or more of rainfall within 24 hours, particularly across Cape Cod and the Islands. However, rainfall totals reaching 1 to 1.5 inches cannot be ruled out.

Temperatures will remain below normal this weekend because of persistent cloud cover and onshore winds. Highs should remain in the 70s both days, with Saturday likely being slightly cooler. Sunday should begin to see some drier air move into the region, helping to reduce cloud cover.

Limited instability is expected because of the cool temperatures and onshore flow. A few embedded thunderstorms cannot be completely ruled out, but the majority of the rainfall should be steady, widespread stratiform rain, meaning rain produced mainly by broad layers of clouds rather than individual thunderstorms.

**KEY MESSAGE 3, Drier and warmer to start next week**

The front should finally move offshore as the upper-level trough progresses eastward and the surface low exits the East Coast. Behind the front, much drier air will move into the region, accompanied by more westerly winds. Clouds should gradually clear and dewpoints will fall through Wednesday.

The base of the upper-level trough will move directly overhead into Tuesday, followed by rising heights as the system continues eastward. High pressure will then become the dominant weather feature, with high temperatures returning to the 70s and 80s.