The New Jersey Turnpike and Garden State Parkway both had lanes in each direction that were virtually impassable by late morning as snow and slush accumulated.
And that was just the first round of a storm expected to come in multiple waves, with snow tapering off to rain in the afternoon, then turning into an even more vigorous snow by evening.
Some parts of central New Jersey had more than 4 inches of snow by midmorning.
In the state's Philadelphia suburbs, the snow gave way to rain around midday.
Valerie Meola, a National Weather Service meteorologist, said the forecast snow totals were increased Wednesday morning as the storm got off to a stronger start than expected.
One band stretching from just outside Wilmington, Del., nearly to New York City, was expected to get over 9 inches by the time the storm ended. Winter storm warnings were put in place until 4 a.m. Thursday.
NJ Transit said buses across the state were delayed by 15 to 45 minutes late in the morning.
There were also delays at Newark Liberty International Airport.