May 16 (UPI) -- Tropical Depression One has become the first storm of the 2020 Atlantic hurricane season on Saturday over the warm waters offshore of Florida.
Tropical Depression One will be upgraded to Tropical Storm Arthur when it is determined that the storm contains sustained winds of 39 mph or greater. A Tropical Storm Watch has been issued for parts of the North Carolina coast by the National Weather Service.
Although the official start of hurricane season is June 1, there has been a preseason tropical system for most of the last 10 years, so it is not uncommon to have tropical activity this early, according to AccuWeather Meteorologist Courtney Travis.
Residents in South Florida saw impacts from Tropical Depression One before it fully developed. A number of flash flood warnings were triggered along the southeastern coast of Florida as heavy downpours and thunderstorms continued on Friday night. Street flooding was reported across the Miami metro area.
Thursday was the second wettest May day on record for the city of Marathon in the Florida Keys. Heavy rain totaled 5.76 inches, stopping short of the city's rainiest May day record of 6.60 inches set on May 27 in 1959. Marathon picked up a total of 6.45 inches from May 14-15, when the normal precipitation for all of May is 3.35 inches.
"Showers will also wet eastern Florida, but rainfall will not be as heavy compared to Friday across South Florida. A brisk onshore wind will keep surf rough along the East Coast of Florida on Saturday, which could produce strong rip currents," AccuWeather Senior Meteorologist Adam Douty said.
The heavy rain and thunderstorm activity seen in the Bahamas and Florida will continue to lift to the north and northeast into Sunday, AccuWeather meteorologists say. The storm and its heavy rain will remain off the coast from northeastern Florida to southern North Carolina this weekend.
According to Dan Kottlowski, AccuWeather's top hurricane expert, the storm will track offshore of the southeastern United States and pass about 75 to 125 miles off the coast of North Carolina's Outer Banks Sunday night into Monday, as Outer Banks beaches reopen to visitors.
The strongest winds will likely remain to the east of the low and across the open waters of the Atlantic; however, coastal parts of the Carolinas could have gale-force gusts Sunday into Monday.
"While it still appears that the worst of the storm will stay offshore, we are monitoring the potential for the storm to track closer to the coast and bring the Outer Banks more substantial rain and wind," AccuWeather Senior Meteorologist Rob Miller said.
Those planning to head to the beach should be aware of the risk of rough surf and strong rip currents that expands northward along the entire Southeast coast this weekend.
Multiple coronavirus testing sites in Florida were forced to close this weekend due to showers and windy weather caused by Tropical Depression One. The 14 state-run COVID-19 testing sites include Brevard Eastern Florida State College's Palm Bay campus and University High School in Orange City. Miami Dade County has temporarily closed all testing sites as well. The testing sites will be closed until Monday, according to the Florida Department of Health.
The 2020 season follows four straight years during which there were at least two U.S.-landfalling hurricanes, with Barry and Dorian striking in 2019. That's the longest streak since 1947-50 and only twice since 1851 has the streak reached at least five years (1932-36 and 1876-82).