Tuesday starts off with patchy fog before 8 a.m. but then look for sunny skies with a daytime high of 84 degrees, the National Weather Service in Islip said.
After midnight there is a 30% chance of showers and thunderstorms and the patchy fog may return.
The odds of such storms during the day Wednesday rise to 40%, the weather service said.
"A slow moving cold front will approach and push off shore by Wednesday night, continuing the chances for precipitation until then," the weather service said. "The main threat with these storms would be heavy rainfall, with minor urban and poor drainage possible."
Skies should be at least partly sunny from Thursday to Saturday, with highs in the low to mid-80s, the experts said.
Rain may return Saturday night and continue into Sunday, however. The odds of showers are 30% both on Saturday night and during Sunday, the weather service said.
A high in the low 80s is expected on Sunday.
Any downpours should clear out in time for a sunny Monday. The high will be around 80 degrees, the weather service said.