Showers and Thunderstorms with Local Downpours Late Saturday Afternoon and Night
The leading edge of an area of showers and scattered thunderstorms will move west to east Saturday afternoon, probably not reaching eastern MA until after 4 or 5 PM (even later for the Cape). Showers and scattered thunderstorms, a few with local downpours, will persist through much of Saturday night before moving offshore by around 8 AM Sunday morning. There will likely be multiple bands of showers with embedded thunderstorms crossing the region Saturday night.
The greatest threat looks to be the risk of intense rainfall where multiple showers/thunderstorms cross the same location. Urban areas would be most susceptible to any localized flash flooding from repeated downpours due to the rapid runoff that occurs in those locations. This risk looks to be highest across CT, RI, and southeast MA. Monitor the latest forecasts and any watches/warnings from the National Weather Service for any potential localized flood threat.
A secondary threat looks to be the potential for a few thunderstorms to produce damaging winds. It’s a pattern where even a short-lived tornado or two is possible. The portion of southern New England most at risk for any localized severe weather would be western MA and CT Saturday evening. Although quite uncertain, that risk might extend further east (especially into RI and southeast MA) late Saturday evening or during the overnight hours. There are some preliminary indications of a potential widespread severe weather outbreak to our southwest over the mid-Atlantic region (including the Philadelphia and Washington, DC areas) during Saturday afternoon and evening.
The cause of the unsettled weather for late Saturday afternoon and Saturday night is an upper level, deepening shortwave trough moving west to east with an associated surface cold front. A warm front ahead of the cold front may move north and then possibly stall for several hours over southern New England. The warm front could add complexity to this weather picture and add to the risk of excessive downpours and very localized damaging winds from wet microbursts or even one or two short-lived and shallow tornadoes. One notable feature of this weather pattern is that the air mass will be especially moisture rich ahead of the cold front, leading to the risk of very heavy downpours. This is, by the way, a situation we’re seeing more frequently in a global warming scenario.
Monitor information from the National Weather Service on any localized developments leading to either a high flash flood or severe weather risk. This blog attempts to highlight the potential for significant weather, including flooding and damaging winds, but is not suited to following up on specific, localized severe thunderstorm or flash flooding developments. It’s best in such situations to monitor real time radar and any warnings/statements from the National Weather Service.
The good news for most folks is that Saturday morning throughout southern New England and most of Saturday afternoon in eastern MA and RI should be dry, albeit with increasing cloud cover. Sunday should feature lots of sunshine and lower humidity – a beautiful day for at least most outdoor activities.
Next Message
Unless there should be a dramatic change for this weekend’s weather, the next weather blog will be the significant weather weekly outlook that is scheduled for Monday July 20. Please note: There will be no weather blog messages July 21 – 27 due to the author being on travel.
About this Blog and Disclaimer
The National Weather Service monitors the weather 24/7 and updates forecasts, watches, and warnings as necessary. For most of southern New England, refer to your local Weather Forecast Office for the latest forecast/warning information at weather.gov/box. For information from other Weather Forecast Offices, go to weather.gov and click on the location of interest on the map.
The frequency of this blog will depend upon the nature of the weather threat and availability of the author. Thus, for the latest information on weather forecasts and warnings, refer to the National Weather Service, which monitors and forecasts the weather 24/7.
Blue Hill Observatory and Science Center (BHOSC)
The BHOSC maintains a continuous daily observation record that dates from February 1, 1885 without interruption and provides educational information on weather and climate to area students and the community at large. Your support of BHOSC is much appreciated and enables this nonprofit organization to maintain the long-term climate record at the Blue Hill Observatory (longest continuous record in North America) and provide valuable educational resources on weather and climate via outreach to schools, site visits/tours, webinars, and conferences. For more information on the Blue Hill Observatory and Science Center, explore bluehill.org.
Message issued July 17, 2026 by:
Bob Thompson
Retired National Weather Service Meteorologist
Blue Hill Observatory and Science Center Board member
