Weekly Significant Weather Outlook
Periods of Heavy Rain Likely across Various Portions of Southern New England From This Afternoon through Thursday Night
An anomalous upper-level low pressure development for this time of year is expected to take place over New York State late today (Tuesday) and very slowly move east through Thursday. An associated surface low pressure system is expected to form near New York City and slowly move along/near the New England south coast. This scenario will result in strong uplift of a moist atmosphere across southern New England with enhanced areas of rainfall where the low-level wind from the south southeast and then more east southeast and eventually east northeast provides uplift over higher terrain. In addition, there will be enhanced downpours due to embedded convection. By Friday morning, most areas of southern New England will likely receive 2 to 4 inches of rain, but some spots will likely have less and a few other spots more. Although subject to change, there looks to be a risk of 4 to 5+ inches across portions of the Berkshires, Worcester Hills, and the higher terrain of western CT where orographic uplift is expected to provide enhancement. The convective component of rainfall so often observed during the summer complicates where the heaviest rain will fall.
Initially, anticipate the heaviest rain to fall across the Berkshires of Massachusetts and western Connecticut this afternoon into tonight and mainly tonight into Wednesday across central MA, eastern CT, and portions of RI (especially northwest RI). The focus of the heavier rain across eastern MA (including the Boston area) will probably be during Wednesday and/or Wednesday night when a moist low level easterly jet may become established as the surface low pressure center slowly heads to the vicinity of the Cape and then into the southern Gulf of Maine. Lingering bands of light to moderate rain may persist through at least Thursday night.
A Flood Watch is in effect for western MA and western/central CT. The combination of heavy rain and the terrain provides the potential for small stream flooding. The Flood Watch may eventually need to be extended further east at least into eastern CT, northwest RI, and the Worcester Hills of central MA. Flooding of poor drainage areas and urban spots is likely across much of southern New England as heavy bands of rainfall move through. Heavy rain and flooding are also threats for east and southeast New York including the Catskills and New York City (mainly this afternoon through tonight).
The various computer models agree with the larger (i.e., synoptic) picture but vary with the smaller scale (i.e., mesoscale) details and hence provide different epicenters for the heaviest rainfall. There are also a couple of models that develop and track the surface low pressure center a little further north which could constrain the heaviest rain across northern MA and portions of northern New England. However, the bulk of the ensemble runs from both the ECMWF and GFS models (including the AI versions) depict the surface low tracking near or a little south of the New England south coast.
At this time, anticipate drier weather for the weekend.
Next Message
The next weekly outlook message will be issued Monday August 3. One or more special weather blog messages may be issued in connection with the heavy rain event this afternoon possibly through Thursday night for various portions of southern New England.
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Message issued July 28, 2026 by:
Bob Thompson
Retired National Weather Service Meteorologist
Blue Hill Observatory and Science Center Board member
