(NewsNation) — Holiday travelers in the northeastern United States could face treacherous driving conditions as the season’s biggest blast of winter is expected to hit several states beginning Friday.

Forecasters are predicting 5 to 9 inches of snow as a winter storm warning stretches from Pennsylvania and into New York, New Jersey and Connecticut. New York City could see among the highest snow amounts, as 9 inches of snow are expected, starting with light, fluffy flakes before the precipitation turns wet and heavy.

New York City Mayor Eric Adams is encouraging drivers not to venture out unless necessary and is encouraging residents to opt for public transportation instead.

Several areas of the region are expected to see snow develop Friday and continue into Saturday, meteorologists predict. Acting New Jersey Gov. Tahesha Way has declared a state of emergency in her state due to the weather system, which could include heavy snow, freezing rain and dropping temperatures.

A wider swath of states, reaching from Ohio to Maine, could be affected by the significant winter storm, forecasters predict.

Some areas could see higher amounts of snow, and the heaviest precipitation is expected to be seen Friday evening, when 1 to 2 inches per hour could fall in certain areas. In New York City, sanitation department workers have started to pre-treat roads, which could become snow-covered as the storm takes shape.