The National Weather Service issued a Winter Storm Warning for Rockland and Westchester at 3:32 p.m. Monday, saying the heaviest snowfall and frigid temperatures would come Tuesday afternoon and evening.
Southern Westchester County could receive up to 10 inches of snow, the NWS said.
According to Joe Pollina, meteorologist for the National Weather Service office in Upton, an arctic cold front will be moving through the area, bringing a blast of winter weather and snow on Tuesday.
"It's going to get a lot colder," Pollina said. Temperatures are expected to hover in the 20s for much of the week and will dip into the teens on Wednesday across the region, with highs in the 30s not expected until Saturday.
Wind chills will bottom out at five to 14 degrees below zero for Tuesday night, experts predicted.
Low pressure will be forming along the cold front off the mid-Atlantic Coast and heading northeast.
Snow showers and flurries will begin early Tuesday morning and get steadier and heavier as the day progresses, affecting the rush hour commute, Pollina said.
Snow accumulations of four to six inches are expected for New York City, with most of Long Island expected to see six to eight inches of the white stuff, and eight to 10 inches forecast for the South Fork.
Snow is expected to end by daybreak on Wednesday.
According to the National Oceanic Atmospheric Administration, the arctic cold front will be first in a series of arctic "surges" plunging southeast across the region through at least Friday.
Patch Editor Lisa Finn contributed to this report.