Long Island forecast: Sunny skies but risk of flooding

The risk of widespread coastal flooding from surging tides will likely continue into next week, according to the National Weather Service, but otherwise, the forecast calls for mostly sunny skies and temperatures in line with autumn's first weekend.

On Friday, "vulnerable areas near the waterfront and shoreline" throughout Nassau and Suffolk counties, as well as parts of the Bronx, Queens and Connecticut, are forecast to get "1 to 2 feet of inundation above ground level," according to various weather service alerts for the region.

The weather service also warned of dangerous rip currents along the South Shore in both Nassau and Suffolk through Saturday evening, with life-threatening rip currents likely for anyone entering the surf zone. The forecast Friday and Saturday calls for partly sunny skies and highs in the mid-70s. There's also a 20% chance of rain Saturday. The evening lows will dip into the mid-50s.

Coastal flooding warnings will be in effect from 9 a.m. to 1 p.m. Friday for the southern Queens and Nassau area, and from noon to 4 p.m. Friday in the Bronx and north Nassau County. From 11 a.m. to 3 p.m. Friday, the weather service calls for a coastal flood advisory throughout Suffolk County. As of Thursday evening, a coastal flood watch exists from Saturday morning through the evening for southern Nassau and southwest Suffolk.

Coastal flooding remains "possible through early next week, especially across LI’s South Shore Back Bays," the National Weather Service said Thursday evening.

The different time frames for potential flooding coincide with the approximate high tide cycles in each area, said Jay Engle, a meteorologist with the National Weather Service’s Upton office, Thursday evening. From watch, to advisory, to warning, Engle said "the flooding typically gets more widespread and the amount of inundation increases. Usually with an advisory, it’s closer to 1 foot of inundation, and it tends to be more for some of the more vulnerable locations."

The string of flood warnings began two evenings after a full moon. As a result, Engle said there is "a high astronomical tide leftover," but "that’s starting to wane." Taking over, the meteorologist said, is an offshore pressure gradient and wind.

"We have a persistent northeast wind, so that’s kind of piling up the water along the coastline," Engle said, adding that the wind "is supposed to stay with us right into Saturday."

Thursday was a "dry day," Engle said, noting the weather service measured no rainfall at MacArthur Airport in Islip. On Friday, the meteorologist said there is "a chance to a slight chance" of rain "mainly for the Twin Forks ... "because there’s a storm off the coast so we could get a disturbance from that."