Long Island weather forecast: Heavy downpours possible

Once upon a midnight dreary? Expect at least that, Long Island.

Forecasters at the National Weather Service said a low-pressure system will bring wet weather overnight Thursday into Friday — and could result in isolated heavy downpours and flooding in low-lying areas.

The weather service said there was a "moderate" risk of excessive rainfall  for Long Island and New York City. 

The service predicted Thursday afternoon that for the entire metropolitan area, including Long Island: "A slow moving coastal low will bring heavy rainfall and the possibility of freshwater flooding late tonight into Friday night. Scattered to numerous areas of flash flooding are possible."

As a result, the weather service issued a coastal flood watch for the metropolitan area, in effect from 2 a.m. Friday through late Friday night, warning: "Breaking waves of 4 to 7 feet will cause significant beach erosion and escarpment, with scattered areas of beach flooding and dune erosion during the time of high tide."

Gov. Kathy Hochul turned to the radio airwaves Thursday evening to warn New York residents not to take the storm too lightly.

“We’re getting used to the rain, but this could quickly morph into a life-threatening, dangerous event,” the governor said on 1010 WINS.

Hochul said that while no road closures or MTA cancellations had been reported as of 6:30 p.m. Thursday, the situation will be monitored through Friday.

“We are really expecting the worst overnight [into Friday morning],” Hochul said. “All New Yorkers need to be vigilant over the next 24 hours.”

Janno Lieber, chairman and chief executive of the Metropolitan Transportation Authority, said Thursday that the agency, which includes the Long Island Rail Road, was “preparing for what looks to be a major storm event.” 

He said the railroad was prepositioning crews at key locations with important equipment, including chain saws to remove tree limbs that fall onto tracks. The LIRR will also have extra staff at its Jamaica Control Center throughout the storm, and will coordinate with U.S. Coast Guard about decisions affecting service on the Long Beach branch, including the potential closure of rail bridges. 

The weather service was predicting 2 to 4 inches of rain will fall Friday and said some areas could receive in excess of 5 inches of rain, with rainfall rates in excess of 1 inch per hour possible.

The daytime high temperature Friday will be about 66 degrees, with a northeast wind of 11 to 15 mph.

Saturday will be mostly cloudy with a 40% chance of rain and a high temperature of around 68 degrees, the weather service says.

Sunday should bring clearing skies and sunshine.

A small-craft advisory is in effect for South Shore coastal waters, ranging from Sandy Hook, New Jersey, to Montauk Point, until Saturday at 8 p.m., the weather service said.