Tropical Storm Danny has formed in the Atlantic near the Dominican Republic and, while it is weak at the moment, forecasters said it could pose a risk to the Eastern seaboard of the United States as it moves north.
On Wednesday evening, the National Hurricane Center said the storm was about 390 miles west of Nassau in the Bahamas, and 735 miles south-southeast of Cape Hatteras, N.C.
Forecasters said the storm is "poorly organized." Maximum sustained winds were 45 mph, and the system was moving toward the west-northwest at about 12 mph.
"A general northwestward motion with a decrease in forward speed is expected tonight and Thursday," the hurricane center said in a statement, "with a turn toward the north-northwest expected on Friday."
The hurricane center uses a dozen different computer models to forecast the path of a storm, combining them to create the forecast map it then makes public. The computer models show the storm likely turning northeastward as the weekend comes, running parallel to the East Coast.
By Saturday afternoon, the hurricane center says the eye of the storm is most likely to be due east of Washington, D.C. Most of the forecast models show it remaining well offshore, but the hurricane center today said tropical-storm-force winds extend up to 140 miles from the eye.
NOAA -- the National Oceanic and Atmospheric Administration, which runs the hurricane center -- cautions people against reading too much into the five-day forecast map it issues. But, based on the computer models, Danny could veer close to Cape Cod and the Atlantic coast of Maine on Saturday and Sunday.
AccuWeather, the private forecasting service, separately said Danny could make landfall as a Category 1 hurricane (winds exceeding 75 mph) late Saturday or early Sunday. It said tropical-storm-force winds could reach North Carolina's Outer Banks Friday, and it warned of dangerous rip currents as the storm moves north.
For now, though, it is labeled as a medium-sized storm. And forecasters say that while they are confident of their ability to track a storm's path, predicting its strength is much more complicated.
"Danny is expected to cause storm total rainfall of 2 to 3 inches, with maximum amounts of 4 inches over the central and northwestern Bahamas. Total rainfall of 1 to 2 inches is expected over the southeastern Bahamas and the Turks and Caicos Islands," the hurricane center said.
Reuters contributed to this report.