Significant Weather Weekly Outlook
Excessive Heat Through Saturday
Excessive Heat Warning for Most of Southern New England and Heat Advisory for the Cape and Martha’s Vineyard
Excessive Heat
Southern New England will experience excessive heat conditions through Saturday with daytime temperatures rising to the upper 90s to around 100 degrees (except 85 to 90 across the Cape and Islands and very immediate south coast). Dewpoints will be in the 65 to 70-degree range. Daytime heat indices will reach 100 to 110 across most of southern New England through Saturday. Overnight temperatures will likely not drop below the 70s and may even not go below 80 degrees in major urban core areas such as Boston. It’s important to take precautions and check on those who could be more vulnerable (elderly, very young, medically compromised, etc.). Some relief in the heat and humidity is expected by Sunday as a cold front finally makes its way through New England. Further cooling is likely into the first part of next week.
Showers/Thunderstorms
Although the heat and humidity (along with an elevated mixed layer) will keep the air mass unstable this afternoon/evening, there’s likely going to be less in way of any broad ascent triggering ascent mechanisms. Nevertheless, there could be isolated thunderstorms this afternoon and evening, and these could quickly become strong.
An approaching cold front and eroding of the upper ridge of high pressure over our area will likely open the door to more widespread showers and thunderstorms Friday through Saturday, although the timing for various locations remains uncertain. Some of these thunderstorms could be strong to severe with a risk of localized damaging wind gusts, frequent cloud to ground lightning, and torrential downpours.
A few models suggest the potential for a weak but moisture laden low pressure area to pass just southeast of New England on Tuesday with the potential for widespread rainfall. Will take a closer look at this in the regularly scheduled weekly outlook to be issued on Monday.
As a reminder, this blog doesn’t attempt to “chase” thunderstorm development. People engaged in outdoor activities should monitor National Weather Service forecast updates as well as any warnings or statements.
Next Message
Will update this blog if greater clarity on convection potential should become apparent for Friday or Saturday. Otherwise, the next significant weather weekly outlook is scheduled for Monday July 6.
Be safe. Wish all of you a Happy 4th of July and 250th birthday of our nation.
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 2, 2026 by:
Bob Thompson
Retired National Weather Service Meteorologist
Blue Hill Observatory and Science Center Board member
