Brace for a coastal storm on Thursday, with as much as one inch of possibly intense rain, the forecasters said.
And it will be cool: the daytime high predicted by the National Weather Service is 52 degrees.
Rounds of showers may last into the night, delivering as much as an additional three-quarters of an inch of rain, as thermometers drop to 40 degrees.
What the weather service calls "nuisance flooding" could occur, starting Thursday evening, the weather service said.
While New England can anticipate wet snow from the same storm, which is linked to a low pressure system over the Great Lakes, only the northern section of the tri-state area is likely to see any snowflakes, according to the weather service and the Weather Prediction Center.
"Any accumulation is expected to be below an inch, and based on surface temperatures, it may be difficult for anything to stick into Friday morning," the weather service said.
While there is a 50% chance Long Island is in for a rainy Friday, Saturday should be sunny, and Sunday at least partly so, the weather service said.
The high during the day on Friday will be 47 degrees, the weather service said.
Saturday and Sunday will see daytime highs in the upper 50s and night time lows in the mid-40s.
Monday may start off dry but showers could arrive by the early afternoon. The odds of rain are 30%. And it will be slightly warmer, with a daytime high just shy of 60 degrees predicted.
Tuesday and Wednesday should be at least partly sunny, with thermometers hitting the low 60s during the day, the weather service said.
That will be slightly warmer than usual, though much cooler than the highs hit earlier this month.
The mean temperature in April for Islip is 49.1 degrees, according to the weather service, whose records date back to 1963.
The maximum temperature is 57.6 degrees and the minimum is 40.6, according to the weather service.