Weather Blog: September 24, 2025 6 PM (Tropics)

TROPICAL WEATHER ACTIVITY MAY APPROACH THE WATERS OFF THE U.S. EAST COAST NEXT WEEK

Tropical Storm Humberto

A couple of tropical systems are being watched in the southwest Atlantic.  One or both may track uncomfortably close to the U.S. east coast next week.  One of these systems was named Tropical Storm Humberto this afternoon.  The second system lies to the west-southwest of Humberto in the northeastern Caribbean Sea (just east of Puerto Rico) and may develop into a tropical depression or tropical storm as it approaches the Bahamas this weekend.

Environmental conditions (warm sea surface temperatures, moist mid-levels, and weak to moderate wind shear) look to be somewhat favorable for both systems to intensify.  Latest computer guidance indicates a fairly high probability of Humberto reaching at least category 2 status in 4 or 5 days.

There is much uncertainty in the eventual track of both systems, especially since the two systems may end up interacting with each other after about 5 days given their eventual proximity to each other.  The odds presently favor Humberto recurving offshore of the U.S. east coast, although there is considerable spread in model projections.  The second system (still a tropical wave at the issuance of this message) may track closer to the Southeast U.S. coast with a few ensemble runs bringing it close to or even onshore the South Carolina or North Carolina coastline.  This system, too, is more likely than not to also remain offshore like Humberto but closer to the U.S. coast, and it will have to be closely monitored.

Potential U.S. Impacts

It’s too soon to conjecture how much impact, if at all, either system may have on the U.S. coastline other than there looks to be a fairly high risk of high surf and rip currents along much of the U.S. east coast, including the Carolinas and the ocean side of the Cape and Islands, next week.  Any boaters planning long trips offshore (especially offshore of the Carolinas) should monitor latest forecasts from local National Weather Service offices and any advisories from the National Hurricane Center.

Hurricane Gabrielle

Gabrielle is gradually weakening as it heads fairly rapidly east-northeast, but it will likely bring hurricane conditions to the Azores Thursday night into Friday.  Gabrielle is also producing swells into the U.S. coastal waters from North Carolina to New England and along the Atlantic Canada shoreline.

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.  For the latest information on Atlantic basin hurricane activity, access the National Hurricane Center website at nhc.noaa.gov.

A blog is issued when there is a potential risk of hazardous weather to southern New England and serve to provide background information regarding the significant weather with somewhat of an educational slant.  In the case of hurricanes, the author will attempt to issue a message when any portion of the United States coastline may be seriously impacted.  It’s intended to complement and not serve as an alternative to official forecasts issued by the National Weather Service.  Readers are urged to check National Weather Service forecasts and warnings for the most timely and updated weather information.  This weather message is solely produced by the listed author and does not constitute an official product of the Blue Hill Observatory and Science Center (BHOSC).

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.

Next Blog

Both Humberto and the tropical wave over the northeastern Caribbean Sea will have to be monitored.  Another message will likely be issued Friday or Saturday.

Message issued by:

Bob Thompson

Retired National Weather Service Meteorologist

Blue Hill Observatory and Science Center Board member