Greater Boston, September 6, 2025
News Summary
A First Alert has been issued for Greater Boston as a potent cold front is set to bring strong to severe thunderstorms on Saturday. The primary window for severe weather will be from 2 p.m. to 10 p.m., with potential risks including damaging winds, large hail, and isolated tornadoes. Residents are urged to monitor forecasts and secure outdoor items in preparation for the storms. Sunday may see varying temperatures and additional thunderstorms depending on the progression of the cold front.
Greater Boston — A First Alert has been issued for Saturday as a potent cold front moves through the region, bringing a threat of strong to severe thunderstorms between the afternoon and evening hours. The primary window for severe weather is expected to be 2 p.m. to 10 p.m. on Saturday, with the potential for damaging straight-line winds, large hail, and an isolated tornado.
What to expect Saturday (most urgent details)
Showers and thunderstorms will develop Saturday afternoon and continue into the evening as the cold front traverses Greater Boston. Most of the area is not expected to see measurable rain until later in the afternoon, with the most significant thunderstorm threat concentrated in the 2 p.m. to 10 p.m. window. Storms during that period could produce damaging winds and large hail, and an isolated tornado cannot be ruled out. Conditions will be hot and humid ahead of the front, with high temperatures in the mid to upper 80s and elevated humidity.
Short-term timeline and supporting details
Friday (prelude)
Friday will feature mixed clouds and sunshine with highs in the mid 80s. Breezy south winds are expected, with gusts up to 30 mph. Humidity will increase through the day, producing feels-like temperatures in the low 90s in some locations. Friday night should trend mostly clear with lows in the upper 60s.
Saturday (severe threat)
Temperatures will remain in the mid to upper 80s with high humidity ahead of the front. The cold front will trigger scattered to numerous showers and thunderstorms later in the day. The most intense storms are forecasted for the afternoon into the evening, and residents should be prepared for the possibility of damaging winds, large hail, and an isolated tornado. Localized impacts such as downed branches, power outages, and hail damage are possible where stronger storms occur.
Sunday (mixed forecast and heat risk)
Forecast guidance contains differing signals for Sunday. Some guidance indicates that Sunday afternoon could see temperatures climb into the low 90s across Greater Boston, marking the 19th 90-degree day or greater this summer, with heat index values in the low to mid 90s. In that scenario, scattered thunderstorms are expected Sunday afternoon into the evening, with the greatest thunderstorm timing around 5–8 p.m.
Other guidance suggests a quicker frontal passage and cooler air arriving Sunday, with rain likely exiting by late afternoon and daytime highs falling into the upper 60s. A severe thunderstorm warning has already been issued for parts of Maine on Sunday, indicating that storm activity will be possible across the broader region.
Weekend evolution and early next week
After the frontal passage, drier air is expected to move in, lowering humidity and pushing temperatures into the mid to upper 70s over parts of the weekend in many areas. However, model differences have left some uncertainty about how quickly and how far the cooler air will spread, contributing to the divergent Sunday scenarios outlined above.
Early next week is expected to feel more fall-like, with highs around the low 70s on Monday and morning temperatures in the low to mid 50s. The region should see a general trend toward lower humidity after the late-week frontal passage.
Coastal and tropical impacts
Hurricane Erin is forecast to strengthen into a major hurricane while over the Atlantic but is not expected to threaten land directly. Despite no direct land threat, the storm will influence ocean conditions, producing high surf, beach erosion, and dangerous rip currents along the New England coast later in the week. Coastal residents and beachgoers should plan for hazardous marine conditions and avoid entering strong surf.
Additional outlook and background
Heat safety is a concern if the warmer Sunday scenario verifies. Heat index values in the low to mid 90s warrant caution for prolonged outdoor activity, and residents are advised to maintain hydration and monitor vulnerable people and pets. Thunderstorm timing late in the weekend could bring localized flooding in brief heavy downpours and exacerbate risks from lightning and gusty winds.
Separate longer-range items included in model guidance note a dry and cold Valentine’s Day with highs in the low 30s and a follow-up round of light winter precipitation the week after, potentially producing light snow accumulations. These items are part of the broader seasonal pattern and remain subject to change as forecasts refine in the coming days.
What residents should do now
- Monitor local forecasts and alerts for updates to timing and severity of storms, especially Saturday afternoon and evening.
- Secure loose outdoor items and consider moving vehicles under cover if strong winds or hail are expected.
- Have a plan to move indoors quickly if severe thunderstorm conditions or tornado warnings are issued.
- For coastal visitors, heed beach advisories and avoid swimming when rip currents and high surf are present.
- Prepare for heat safety on days when high heat or high humidity is forecasted—drink water, take breaks indoors, and check on vulnerable individuals.
FAQ
Will Saturday’s severe weather affect all of Greater Boston?
The severe risk is regionwide during the 2 p.m. to 10 p.m. window, but impacts will vary. Some communities may see only scattered thunderstorms, while others could experience stronger storms with damaging winds and hail. Much of the area is not expected to receive rain until later in the afternoon.
How likely is a tornado on Saturday?
An isolated tornado is possible but not the most likely outcome. The primary threats are damaging straight-line winds and large hail. Residents should monitor watches and warnings for any upgrade to tornado guidance.
Should I cancel outdoor plans this weekend?
If outdoor activities are scheduled for Saturday afternoon or evening, consider a backup plan and be prepared to move indoors quickly. For Sunday, check later forecasts for the evolving temperature and storm scenarios before finalizing plans.
What coastal hazards should beachgoers expect?
High surf, beach erosion, and dangerous rip currents are expected along the New England coast later in the week due to Hurricane Erin’s influence over the Atlantic. Beachgoers should avoid entering the water when advisories are in effect and follow local beach safety guidance.
How can I stay informed?
Keep devices charged, enable weather alerts, and review up-to-date forecasts and warnings throughout the day, especially from afternoon into evening on Saturday.
Quick reference table
| Day / Time | Expected Conditions | Key Risks and Advice |
|---|---|---|
| Friday (Day) | Mixed sun and clouds; highs mid-80s; breezy S winds, gusts up to 30 mph; increasing humidity | Heat index low-90s in spots; hydrate and limit strenuous outdoor activity during peak heat |
| Friday (Night) | Mostly clear; lows upper-60s | Minimal impacts |
| Saturday (Afternoon–Evening) | Cold front triggers showers and thunderstorms; highs mid–upper 80s and humid | Primary severe window 2–10 p.m.. Risk of damaging winds, large hail, isolated tornado. Have a safety plan |
| Sunday | Forecasts differ: possibility of low-90s and heat index low–mid 90s with storms 5–8 p.m., or quicker cool-down with highs upper-60s after rain exits | Monitor updates. If hot, follow heat safety guidance; if storms, be alert for lightning and gusts |
| Coastal later in week | High surf, beach erosion, strong rip currents related to Hurricane Erin | Avoid swimming in hazardous surf; follow local beach advisories |
| Early next week | More fall-like: highs near low-70s Monday; mornings low–mid 50s | Cooler and less humid |
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Additional Resources
- NBC Boston: Sunday Forecast – Heat & Storms
- Wikipedia: Weather Forecasting
- NBC Boston: Boston Weather – Humid & Scattered Storms Possible
- Google Search: Weather Forecast
- NBC Boston: Boston Snow Forecast
- Google Scholar: Weather Forecasting
- NBC Boston: Massachusetts Weather – Noreaster Spoil Holiday Weekend
- Encyclopedia Britannica: Weather Forecast
- NBC Boston: Next Snow Storm Forecast
- Google News: Boston Weather
Author: STAFF HERE BOSTON WRITER
BOSTON STAFF WRITER The BOSTON STAFF WRITER represents the experienced team at HEREBoston.com, your go-to source for actionable local news and information in Boston, Suffolk County, and beyond. Specializing in "news you can use," we cover essential topics like product reviews for personal and business needs, local business directories, politics, real estate trends, neighborhood insights, and state news affecting the area—with deep expertise drawn from years of dedicated reporting and strong community input, including local press releases and business updates. We deliver top reporting on high-value events such as Boston Marathon, Head of the Charles Regatta, and Boston Harborfest. Our coverage extends to key organizations like the Greater Boston Chamber of Commerce and Associated Industries of Massachusetts, plus leading businesses in finance, biotech, and insurance that power the local economy such as Fidelity Investments, Biogen, and Liberty Mutual Insurance. As part of the broader HERE network, we provide comprehensive, credible insights into Massachusetts's dynamic landscape.
