We have an early March Nor’easter roaring on our doorstep. Already some rain showers have spread into New Jersey and rain will intensify and become more widespread overnight.
Our developing Nor’easter is working with a lot of moisture. Follow the subtropical jet stream from the mid-Atlantic all the way back to the tropical Pacific. This train of moisture, stretching all the way back to Hawaii, sets the stage for flooding rains over the next 36 hours or so.
Closer to home, there is energy embedded within a northern branch of the jet stream has dropped down from the northern plains and Great Lakes region, and is interacting with this moisture across the mid-Atlantic. As these two streams phase, we will see this primary low fizzle out, as a coastal low rapidly intensifies and takes center stage, weather wise, for New Jersey over the next couple of days.
The radar shows the slug of rainfall moving into New Jersey at this moment. Interestingly some radar returns are breaking out across southern New Jersey and off the coast, suggesting that the coastal low is starting to take over.
Expect a long duration, high impact event, with up to 2 inches of rain, and a rain to snow scenario along the northern tier. Our nor’easter has pressured down below 975 mb which is very impressive. The pressure gradient aloft starts to tighten, and that’s when we start to transition from a rainstorm to a wind storm. Everyone statewide sees strong winds bringing the threat of widespread power outages. Everyone would be wise to be well prepared — check your emergency kit and do what you need to do in the event of widespread power loss or a flooding scenario.
Down the shore, Friday evening brings the first round of high tide flooding. With persistent north or northeast winds expected for several days, every high tide through Sunday brings the risk of flooding. Saturday morning will be the peak, when levels will reach the threshold for major flooding at most coastal reporting stations, especially for the northern half of the coastline. Residents along the shoreline and near rivers that experience tidal flooding regularly should prepare for a very serious flooding event.
Snow totals will be highest in Sussex County and other elevated portions of northwest New Jersey. If you’re under the heaviest bands it will be a wet, pasty snow that accumulates. If you’re not in one of these bands, you’ll see rain or non-accumulating snow. Elevation will also matter in this setup. If you’re at 1,000 feet, or higher, there’s less warm air near the surface that the snow needs to fall through to accumulate. That’s the story for northwest New Jersey. It’s possible that the stronger bands bring a stripe of significant snowfall to a broader part of north or central New Jersey, but it’s touch and go of an atmospheric situation, you can’t know if that’s going to happen until its practically occurring. Regardless, rain and wind should be enough of a deterrent to keep people off the roadways Friday afternoon and night. We dry out on Saturday, and at that point the focus shifts to flooding issues down the shore.