Sunny, cooler weekend for Long Island but 78 beaches impacted by no swimming advisories due to storm runoff bacteria

The powerful rainstorm that pelted the region with heavy rain has moved out, leaving, in its wake, a much cooler, cloudy Friday, to be followed by a lovely weekend — marred only by advisories against bathing and closures affecting 78 beaches on Long Island. 

"A wonderful weather weekend is on tap with a large dome of high pressure being in control ... to begin the weekend for Saturday. Expect plenty of sunshine both days this weekend with cooler ... temperatures, " the National Weather Service forecast said Friday. Both days will see temperatures around 80 degrees and lower humidity and temperatures at night in the 60s.

Despite the beautiful weather, Thursday's heavy rainfall has led to an advisory against bathing at mostly 62 North Shore beaches in Suffolk. Ronkonkoma Beach, on Lake Ronkonkoma in the Town of Islip, also remain closed to swimming.

In Nassau, the local health department has issued an advisory not to swim in 14 North Shore beaches and 2 South Shore beaches.

All were impacted by storm runoff produced by the heavy rains, which elevated bacteria beyond state standards.

"Health Officials recommend that bathing and other water contact be suspended in affected areas until the waters have been flushed by two successive tidal cycles (at least a 24 hr. period) after the rain has ended," a Suffolk health department release said.

The advisories will be lifted at 8 a.m. Saturday unless sampling shows bacteria levels have not gone down, the health departments said. 

Long Island was spared the worst of the storm but some areas did experience flooding. Service was restored early Friday to the LIRR's Port Washington Branch, which had been affected by the storm.

The branch was suspended for most of the day Thursday, east of Flushing-Main Street in both directions, due to high water, according to the MTA.

"Service on all LIRR branches is on or close to schedule, including on the Port Washington Branch, where repairs were necessary because water got onto the tracks," Long Island Rail Road spokeswoman Renee Price said early Friday, adding that both tracks of the branch were restored around 6:30 a.m.

"Approximately 80 employees worked through the night to restore service including plumbers, power, signal, and track personnel," she wrote in an email. "The excessive water from street level at both Bayside and Great Neck caused wash out conditions where soil, ballast, and even railroad ties were washed away."  

Numerous roads were closed on the South Shore Thursday due to flash flooding, as law enforcement shut down streets from Medford to North Bellport and throughout Holbrook, the service said on its website. 

The heaviest rainfall during the storm totaled 5 inches in Queens, with between 1 and 3 inches on Long Island. Sayville received the most rainfall in all of Long Island with 4.59 inches.

In Nassau County, the service said it also had reports of flooding in Levittown at the intersection of on the intersection of Chimney Lane and Loring Road.

Great Neck received 3.35 inches of rainfall, the most in Nassau County. A video shared with the service showed water spilling over onto the LIRR Great Neck train station platform and tracks, its website said.

Merrick, Levittown, and Seaford were the only other Nassau areas that received more than 2 inches of rain.

There is a high risk of rip currents at all ocean beaches in Suffolk County, weather service meteorologist Dave Radell said.

"There’s a good likelihood that you could be swept out if conditions are right and you’re not a very strong swimmer," he said. And the risk could be life-threatening, he noted.

Newsday's Maureen Mullarkey contributed to this story.

By Matthew Chayes

matthew.chayes@newsday.comchayesmatthew

Matthew Chayes, a Newsday reporter since 2007, covers New York City.