As we progress further into the spring and eventually into the summer, the jet stream will progressively move northward bringing more pleasant weather to New Jersey.

Jet Stream (State Climate Office of NC)

Seasonal Differences in the Jet Stream

The strength of the jet stream depends on the temperature difference of the cold arctic air to the north and warm tropical air to the south. The jet stream is strongest during the winter when temperature difference is greatest across the United States. The jet stream is the weakest during the summer when temperature differences across the United States are smaller.

A zonal flow pattern occurs when there is a small-amplitude pattern in the jet stream and results in mostly west-to-east winds. Cold air tends to stay toward polar regions and warm air remains equator-ward. When you have a weak jet stream with a zonal flow (horizontal orientation of the jet stream), it is indicative of warmer temperatures and calm weather.

A meridional flow pattern in the jet stream occurs when the wave have large amplitude with deep troughs and peaked ridges. Cold air flows equator-ward and warm air flows poleward. When you have a strong jet stream with a meridional flow (north-south orientation of the jet stream), it is indicative of cooler temperatures and strong storms.
The jet stream moves either north or south depending on the elevation of the sun. As the sun’s elevation increases each day in the spring until summer, the jet stream moves north into Canada. As the sun’s elevation decreases each day in Autumn until winter, the jet stream moves south into the United States bringing cooler air to the country.

Implications for New Jersey

Looking at the weather animator of the 300 millibar jet stream for the rest of the week and into next week, the jet stream seems to have shifted north. Although the flow of the jet stream is not completely zonal, it has a very weak meridional flow to it. Its ridges and troughs are not that amplified.

All of this means that warmer and more pleasant weather is approaching. It does not rule out the occasional shower here and there, but warmer temperatures are definitely approaching in the upcoming week.