Weather for New England and the Northeast

**Area Forecast Discussion, National Weather Service Boston/Norton MA**
**327 PM EDT Sunday July 26 2026**

**What Has Changed**

Shower chances and the potential for flash flooding have been refined for the upcoming week.

**Key Messages**

* Low impact weather through Monday night. A few thunderstorms are possible Monday afternoon across western portions of southern New England.

* Periodic chances of scattered showers and thunderstorms early to mid week, potentially lingering into Thursday. Increasing potential for heavy rain late Tuesday through Wednesday, with at least localized flash flooding possible.

**Discussion**

**Key Message 1, Low impact weather through Monday night. A few thunderstorms are possible Monday afternoon across western portions of southern New England.**

A weak area of low pressure continues to spin southeast of Nantucket, keeping low clouds and occasional light precipitation across the outer Cape and Islands. While it will not be the best beach day there, a High Risk for rip currents continues through this evening along the east facing beaches of Cape Cod and Nantucket.

Elsewhere, most of southern New England will enjoy sunshine and comfortable conditions. The rest of today and tonight will remain quiet. Moist air near the ground, combined with a light northeast breeze and mostly clear overnight skies, may allow patchy fog to develop in the usual low lying areas and river valleys across eastern Massachusetts.

Overnight temperatures will fall into the 50s inland and the lower 60s along the immediate coast, which is typical for late July.

Monday will bring seasonable temperatures, with highs in the lower to middle 80s inland and the upper 70s along the coast.

A small disturbance in the upper atmosphere, known as a shortwave trough, along with another disturbance several thousand feet above the ground between about 5,000 and 10,000 feet, will provide enough lift to trigger isolated to scattered showers and thunderstorms during the middle to late afternoon. These storms will mainly develop west of the Connecticut River Valley.

Atmospheric moisture will increase to around 1.3 inches, which is near to slightly above normal for this time of year. While a few storms could produce locally heavy rainfall, precipitation amounts should generally remain modest, with isolated totals approaching one half inch.

Flash flooding is not expected because it would take roughly 2.5 to 3.0 inches of rain within three hours to create flooding problems.

The atmosphere will become moderately unstable Monday afternoon, supporting thunderstorm development. However, winds at different heights of the atmosphere will remain relatively weak, limiting storm organization. As a result, storms should stay isolated, remain relatively short lived, and many communities will stay dry.

The greatest chance for storms remains west of the Connecticut River. Colorado State University machine learning guidance also indicates the better chance for severe weather will remain west of eastern New York. Severe weather is not expected, but any thunderstorm could produce cloud to ground lightning and brief periods of locally heavy rainfall.

Monday night, any remaining thunderstorms will fade during the evening. Winds higher in the atmosphere will shift to the southwest, bringing additional moisture into the region. Atmospheric moisture will increase to around 1.5 inches. Low clouds will become more widespread overnight, and scattered light showers may begin developing ahead of a more unsettled weather pattern arriving Tuesday. Overnight temperatures will remain mild, staying in the 60s.

**Key Message 2, Periodic chances of scattered showers and thunderstorms early to mid week, potentially lingering into Thursday. Increasing potential for heavy rain late Tuesday through Wednesday, with at least localized flash flooding possible.**

A broad upper level trough, an elongated area of lower atmospheric pressure aloft, will remain over the region through much of the week. Several smaller disturbances moving through this pattern will support repeated chances for showers and thunderstorms.

Forecast models continue to show good agreement that the upper level trough will strengthen Tuesday into Wednesday while drawing unusually moist air into southern New England. Atmospheric moisture is forecast to reach 120 to 170 percent of normal for late July.

Most forecast models now indicate a developing low pressure system that could become unusually strong for this time of year. Combined with abundant moisture and stronger upward motion in the atmosphere, this creates an increasingly favorable setup for heavy rainfall.

Some forecast models remain more aggressive than others. The European model continues to show the strongest signal for heavy rain and flash flooding, with a stronger low pressure system tracking near Long Island and then toward eastern Massachusetts and Cape Cod. This solution also keeps the weather system moving more slowly, increasing rainfall totals.

Forecast soundings, which are vertical profiles of the atmosphere, show an environment highly favorable for efficient rainfall production. European ensemble guidance indicates a 40 to 75 percent chance of at least 1 inch of precipitation from late Tuesday into Wednesday, along with a 10 to 40 percent chance of more than 2 inches across much of southern New England.

Recent model runs also show widespread areas receiving more than 2 inches of precipitation during that period.

Because steering winds will be weak, thunderstorms will move slowly. Some storms may also repeatedly move over the same locations, a process known as training. This combination increases the risk of localized flash flooding, with scattered flooding problems becoming possible rather than just one or two isolated incidents.

Recent Canadian and American forecast models have also moved toward a wetter solution, although their ensemble forecasts still show some scenarios with a weaker low pressure system and lower rainfall amounts. Even in those solutions, localized heavy rainfall and flash flooding remain possible.

There is still some uncertainty regarding the exact track and strength of the storm system. However, confidence is increasing that southern New England will experience widespread rainfall, with localized heavy downpours and flash flooding possible, especially from late Tuesday through Wednesday. Depending on the eventual track of the low pressure system, showers could linger into Thursday.

Temperatures through the week are expected to remain seasonably cool to slightly below normal, generally ranging from the middle 70s to the lower 80s.