As the Gulf Coast is preparing for Harvey’s third landfall, this time along the southwestern coast of Louisiana as this storm continues to dump even more rainfall on already record-breaking floods, back here in New England, our eyes are turned to the East Coast, where a blossom of rain and thunder continues to slowly converge around Tropical Depression number 10 off of the North Carolina coast.
Whether the Tropical Depression ever organizes enough to be named Tropical Storm Irma is of little consequence to New England — the impact for us will be the same, regardless: a period of windswept rain and showers.
After a dry Tuesday with thickening clouds, showers will arrive from the south, impacting the South Coast first around likely around sunset, between 6-9 p.m., the rain then expands northward during the overnight to around the Merrimack Valley, dropping generally a quarter to a half inch of rain over Southern New England, less in the Merrimack Valley, and closer to an inch or a little more than that from Chatham to Nantucket.
Although most of us won’t see much wind, a northeast wind will increase in the squeeze between high pressure departing to our east, and Tropical Depression number 10 — an area of low pressure — passing to our south. The result will be a strong northwesterly wind late Tuesday night to Wednesday morning on the Outer Cape and Islands, with a couple of gusts to 40 or 45 miles per hour a possibility, particularly on Nantucket. This will be the equivalent of a weak to moderate nor’easter, and should require little more than an additional fender on the boat. Coastal flooding is unlikely with a rather low tide.
Any showers will quickly depart Wednesday, leaving increasing sunshine from midday onward, setting the stage for some great, slightly cooler, weather into the start of the holiday weekend, save for some scattered Thursday afternoon showers into northwestern New England as a cold front slips in from Canada. Friday is cooler with highs into the upper 60s, Saturday brings highs back into the 70s under drier conditions both days.
By Sunday, deeper warmth will begin a move to New England, and this should bring some clouds and a chance for scattered showers, then a warm Labor Day is probable with a chance of scattered afternoon thunder.