Long Island weather: Heavy rain Friday into Saturday

Cloudy skies and occasional drizzle and showers Thursday and Friday are setting the stage for a drenching launch of the weekend that could include significant coastal flooding at both Nassau County's southern and northern edges, forecasters say.

Meteorologists have issued a flash flood watch for late Friday into Saturday afternoon, when considerable amounts of rain -- up to 2 inches -- will pour onto Long Island with potential to ravage coastal areas while flooding urban areas, low-lying roads and small rivers regionwide. While the heavy rain is not expected until Friday, forecasters said that low-to-moderate coastal flooding could arrive on Long Island on Thursday night during high tide.

The report of a deluge was issued by the National Weather Service, based in Upton, at about 6 p.m. Thursday. And it forecast a dramatic turn of events from the weather report for much of the day, which included 53-degree conditions under cloudy skies and winds from the southeast of 23 mph at Long Island MacArthur Airport.

The normal high for the day at the Ronkonkoma airport is 59 degrees, with 41 the normal low.

With strong winds expected from the south/southeast, as well as the soon-to-be full moon, News12 Long Island meteorologist Rich Hoffman advised those in Nassau County south of Merrick Road to be alert for coastal flooding with Thursday evening’s high tide.

A coastal flood advisory was in place from 7 p.m. to 10 p.m. for Nassau’s southern shorelines Thursday but the morning of Good Friday brings areas of fog and chances of showers, as a system packing plenty of tropical moisture arrives Friday night, the start of Passover, into Saturday, Hoffman said. 

Expect waves of between 8 and 12 feet along the oceanfront Friday night into Saturday as well as beach flooding and dune erosion along the Atlantic Ocean beachfront, meteorologists said.

Friday’s high is expected to reach 64 degrees with a low of around 56, forecasters said.

The forecast is for moderate to heavy rain to develop Friday night, wrapping up by Saturday afternoon, the weather service said. That comes with the likelihood in some areas of minor nuisance, poor drainage and urban flooding. Localized flash flooding is also possible with any heavy showers and embedded thunderstorms that move over the same area.

Winds could also gust up to 40 mph.

As for Easter, the day could see a spotty shower or two, Hoffman said, but for the most part the day is dry.

Saturday and Sunday should both have highs near 60.