Get ready for the winter whipsaw.

Springlike conditions were in the forecast for North Jersey Saturday, with a high of around 60 degrees expected and even a potential for thunderstorms, the National Weather Service said.

But temperatures will fall back to the 30s by Sunday night. And by Monday, a major winter storm could barrel into the region, bringing several inches of snow and “significant travel disruptions.”

As of Saturday morning, the Weather Service’s Mount Holly office’s “expected snowfall” forecast had as much as 2.1 inches falling though much of Bergen and Passaic counties through Tuesday morning, with 3.6 inches in northern and western areas of Morris and Passaic counties and all of Sussex.

The “high end” forecast pushed that to 3-5 inches closer to New York City and as much as 8 to 10 inches in western New Jersey, but the Weather Service said current models put the likelihood of that at about 10%.

“Subtle shifts in track north or south will impact the location of heaviest precipitation and where the rain/snow line sets up,” the agency cautioned. “This will be key in determining forecast snowfall amounts, particularly for the city/coast, in an air mass only marginally cold enough to support snow.”

Here’s what we know as of Saturday morning. Check back with us through the weekend as the forecast develops.

Saturday

Forecasts call for a mostly cloudy day with a chance of rain and highs in the upper 50s to low 60s. There’s a possibility of thunderstorms in the evening.

Sunday

Sunday will be mostly cloudy with highs in the upper 40s. But temperatures are expected to dip back to around 30 degrees by nighttime.

Monday and Tuesday

The Weather Service expects a mostly sunny day with highs in the 40s. Then, the fun starts, with rain turning into sleet and snow around midnight.

A low-pressure system will “bring a period of moderate to heavy precipitation, gusty winds, and minor to locally moderate coastal flood impacts,” the agency’s New York office said, with a “40-60% chance of 2 inches or more by daybreak Tuesday for interior locations north and west of NYC.”

This article originally appeared on NorthJersey.com: North Jersey forecast: Major snowstorm could follow mild weekend