Potential Tropical Cyclone 10 may slowly evolve into Tropical Storm Irma near the southern Atlantic coast while surf, drenching showers and gusty coastal winds increase through midweek.
The main impacts will be locally dangerous surf and rain that slows travel for a while or ruins a day at the beach.
A period of rain is forecast from Charleston, South Carolina, to Wilmington, North Carolina; Norfolk, Virginia; Ocean City, Maryland; Philadelphia; Atlantic City, New Jersey; New York City and Martha’s Vineyard, Massachusetts.
Small craft operators should exercise caution outside of protective intercoastal waterways as the potential tropical cyclone may kick up waves and winds in a hurry once it catches hold.
The tropical disturbance, originally dubbed 92L, has been pestering Florida with downpours for nearly a week. Fort Myers, Florida, has received nearly 14 inches of rain since Wednesday, Aug. 23.
“Downpours will continue over the Florida Peninsula into Monday night and will raise the risk of isolated urban and low-lying area flooding,” according to AccuWeather Storm Warning Meteorologist Richard Schraeger.
As the tropical disturbance drifts to the northeast, downpours will diminish over much of the Florida Peninsula on Tuesday.
The center of the disturbance is currently poorly defined. However, the feature will remain over the warm waters of the Gulf Stream, and a non-tropical system to the north is likely to help generate some spin and increase winds in the region.
Gradual development into a tropical depression or storm is anticipated over the next few days, especially from Monday night on. The next name on the list of tropical storms for the Atlantic this year is Irma.
“Winds around the disturbance are estimated to be just under tropical storm force, so just a small amount of organization will bring it to tropical storm status,” according to AccuWeather Hurricane Expert Dan Kottlowski.
Into Wednesday, a non-tropical system to the north will help add wind along the coast from Georgia to Massachusetts and add spin to the tropical disturbance.
“Because of the blend of tropical and non-tropical characteristics, the system may be dubbed a sub-tropical storm as it moves along,” Kottlowski said.
These winds could become as punchy as that of a modest nor’easter. Gusts on the Outer Banks in North Carolina and the Virginia capes may reach between 40 and 50 mph. The wind direction will vary from east to northeast and north and later northwest.
This animation shows Potentical Tropical Cyclone 10 as a mass of showers and thunderstorms along the southern Atlantic coast of the United States on Monday, Aug. 28, 2017. (NOAA/satellite)
The winds will cause seas and surf to build along much of the Atlantic Seaboard. Where the winds blow the strongest, from eastern North Carolina to the New Jersey cape, minor beach erosion can occur with minor coastal flooding possible at times of high tide.
The increased wave action will also pose a risk to bathers much of this week. The number and strength of rip currents will increase from the east coast of Florida to Cape Cod, Massachusetts. Bathers should exercise caution and venture into the water only where lifeguards are still on duty. Surf conditions may improve from south to north during Thursday, Friday and Saturday.
The combination of the disturbance and the non-tropical feature will allow a batch of locally drenching rain to roll northward along the Atlantic Seaboard.
Rain will spread from South Carolina into Monday night to southeastern Virginia on Tuesday to Massachusetts on Tuesday night. In most cases, the rain will last 12-24 hours.
It is possible enough rain falls to cause a few incidents of urban flooding that will far pale in comparison to ongoing events in Texas and southwestern Louisiana due to Harvey.
During the latter part of the week, the tropical feature will head out to sea over the North Atlantic. Some additional strengthening may take place several hundred miles southeast of New England and south of Atlantic Canada.
“Elsewhere in the Atlantic, another tropical disturbance, currently approaching the Cabo Verde Islands, has the potential to develop into a tropical storm late this week,” Kottlowski said.
This new disturbance may approach the Leeward Islands next week.