Tropical moisture and a developing storm system will threaten to ruin a day at the beach this weekend from the Outer Banks of North Carolina to Cape Cod in Massachusetts.
A zone of drenching showers and thunderstorms over the Atlantic Ocean is forecast to drift northwestward and approach the beaches from the mid-Atlantic to southern New England.
The risk of rain will spread from North Carolina on Saturday to Virginia, Maryland, Delaware and New Jersey during Saturday night, then to Long Island, southern Rhode Island and southeastern Massachusetts on Sunday.
According to AccuWeather.com Hurricane Expert Dan Kottlowski, "Storm systems that brew over the warm waters along the Atlantic coast this time of the year tend to overachieve and this one will be monitored closely."
While the system will be just a nuisance it may attain some tropical characteristics.
"A high pressure area to the north could cause winds to kick up more than you might expect from an area of downpours and a weak low pressure area," Kottlowski said.
"The system is not likely to have enough time to strengthen a great deal before being ejected out to the Northeast off of Cape Cod by Sunday night."
By late Sunday, it is possible the system is organized enough to bring some wind and rough seas along with rain around Cape Cod.
A wedge of dry air in the lowest layer of the atmosphere is likely to keep rain away from most cities along the I-95 corridor this weekend. However, more clouds will spread over the region and there is a chance of a downpour in Washington, D.C., on Sunday afternoon and in Boston during Sunday night.
A system responsible for drenching rains and flash flooding in the South Central states during this past week will weaken, but drift northward into early next week.
As that system arrives, more typical, late-July humidity levels and temperatures are forecast for the mid-Atlantic overall and part of New England by early next week, which will lead to spotty showers and thunderstorms on a daily basis.
How warm the weather gets from location to location each day will depend on the amount of sunshine. Even a few hours of partial sunshine in the forecast pattern for next week can be enough to drive the temperature to near 90 F or higher.