The National Weather Service has issued a dense fog advisory for most of Long Island Sunday night into Monday morning.
The service said the fog will continue through at least 2 a.m. and visibility could be down to between one and two miles, and perhaps a quarter-mile or less near the coast.
Stormy weather will roll in Monday with showers expected to last, on and off, most of Memorial Day, forecasters said.
“Showers and thunderstorms move in after midnight, and the low will be in the mid-60s,” said Jay Engle, a meteorologist with the National Weather Service in Upton.
The weather service also warned Sunday of possible flash flooding late Sunday night and Monday.
Monday will be a “rotten” day, News 12 meteorologist Norm Dvoskin said. The rain will be heavy at times and the high will be 72.
“Memorial Day is not going to be a great day,” Engle said. “There’s a 90 percent chance of rain — one to two inches or more.”
Monday night, the chance of rain drops to 50 percent, he said.
A mix of sun and clouds is ahead for Tuesday, when highs will be near 77 and lows near 62.
Another sun-and-clouds mix is forecast for Wednesday. Highs will be near 75 and lows near 59.
Thursday will be mostly cloudy with highs near 73 and lows near 57.
Another mostly cloudy day is predicted for the beginning of the weekend on Friday when there is a chance for a thunderstorm and highs will be near 72 and lows will hover around 60.
“We’ve had above-normal temperatures and now we’re going to be closer to normal,” Engle said. He said the normal high at Islip for this time of year is 71 and the low is 54.