Temperatures on Sunday will be in the low 40s, with clouds covering the sky for much of the day, said David Stark, meteorologist with the weather service's Upton bureau. Lows will dip into the low 30s overnight.
Monday will be the highlight of the week weather-wise, with mostly sunny skies providing highs in the mid to upper 40s, Stark said. By Monday night, increasing clouds and lows in the lower 30s will give a taste of what's to come on Tuesday.
Stark said forecasters are keeping an eye on a developing low-pressure area that could bring rain, snow, or a mix of the two to the region.
"If it tracks close enough to the coast, we could see a rain-snow mix across Long Island for most of the day on Tuesday," Stark said.
The system could also stay far enough away from the coast that Long Island would see very little precipitation in the form of light snow or rain, Stark said. If it tracks closer to the coast, he said the system would be more rain than snow due to the warmer air in the area.
Regardless of where the system ends up, "we feel pretty confident it will not be a significant event," he said.
High temperatures on Tuesday are forecast to be near 40 degrees, with lows near freezing.
Wednesday will begin a dry, cool trend for the rest of the week, with lingering clouds and temperatures in the lower 40s. Lows will be around freezing overnight.
Thursday's highs will be around 40 degrees, with lows in the upper 20s to low 30s, Stark said, while Friday's highs will also be around 40 degrees.
Highs at the end of the week will be nearly 10 degrees lower than the average for this time of year, thanks to cool air moving south from Canada, Stark said.
But don't prepare to hunker down for a deep freeze just yet. Stark said chillier-than-average temperatures now don't necessarily mean the same for this winter.
"The official forecast for winter still shows both sides of the equation," Stark said. "We could end up seeing above-average temperatures or below-average temperatures."