The cold front that had helped to cause the thunderstorms and heavy downpours over the past couple of days is finally working its way through the area, which will gradually clear our skies as the day goes on. However, the front will be slow to move through the area, given the strong western Atlantic ridging. Combining this with an extremely powerful mid and upper level disturbance, placing us in the right-entrance region of the jet stream, there will still be plenty of clouds around and some showers, with locally heavy downpours. That being said, considering the cold front has shifted to the east, the biggest threat for heavy rain should stay to the east of NYC.
The powerful 500mb low is actually a piece of the Polar Vortex, which explains why it is so strong and is bringing chilly temperatures to the Midwest, where temperatures even fell into the 30s this morning! Out ahead of it, strong southwest flow persisted for days, providing a conveyor belt of moisture and instability for thunderstorms. Now that the cold front is finally moving eastward, the conveyor belt also shifts eastward, which puts a limit to the coverage of rain. Most of New Jersey should stay rain-free, but clouds will remain for most of the day, thanks to the 100 + knot jet streak shown in the bottom-right panel. Long Island may have to deal with some rain and locally heavy downpours as we head through the morning.