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Coastal storm likely early next week

Although it may seem like we’re beating the same old drum, here we are again — a significant coastal storm looks increasing likely early next week. Forecast models have come into much better agreement on the evolution of the mid and upper level atmospheric pattern across the Continental United States from late this week into this weekend. After a weekend rain event and weak disturbance, two additional disturbances in the mid levels of the atmosphere will move eastward from the West Coast. The first will settle into the Southeast States, while the second will be dropping southeastward from the Northern Plains into the Mississippi Valley. The two disturbances will interact, and possibly phase, early next week — and the end result will be a strengthening Nor’Easter on Tuesday.

The questions, now, become more related to specifics and the sensible weather that these features will bring. The strengthening coastal storm is likely to feature tremendous amounts of moisture and impressive dynamics aloft, but the exact track and intensity of the storm system will obviously significant impact what we see in our area. At this time, the potential is heightened for a multi-hazard Nor’Easter to impact our area from Tuesday into Wednesday, but our confidence in the areas impacted highest and the hazardous weather that our entire area experiences is low.

How is this storm forming? 

It begins out west, with two disturbances crashing on to the West Coast of the United States Saturday morning. One remains in the “southern” portion of the jet stream, tracking from California to Arkansas during the weekend. The other comes through in the Pacific Northwest and takes a “northerly” track, moving from Washington State to North Dakota this weekend. The northern disturbance will eventually be pushed southeastward by a building West Coast Ridge, and race southeastward toward the Mississippi Valley. Eventually, it will interact with the southern disturbance near the Mid-Atlantic.

Forecast models show two distinct disturbances over the Central US this weekend which will phase early next week.

Forecast models show two distinct disturbances over the Central US this weekend which will phase early next week.

A baroclinic zone, or a temperature gradient, off the East Coast will serve as a “highway” for the initial low pressure system to develop as a result of this phase. And the mid and upper level jet orientation argues that the storm may strengthen fairly rapidly — with its central pressure possibly dropping into the 990’s. Significant moisture drawn into the storm could be thrown back toward the coast as the storm develops into a mature cyclone, moving from a position off of the Outer Banks of North Carolina to near the 40/70 Lat/Lon Benchmark for Nor’Easters on Tuesday into Wednesday.

What hazards could this storm bring to our area? 

The storm could be a multi-hazard event, with impacts varying greatly by location. This is not atypical for Nor’Easters, but each storm is different and we will obviously be tracking more specific details as the event draws closer. Should the storm track close to the coast, as many forecast models indicate it will, the main threat would be heavy rain and wind…especially along the coastal plain. The impressive mid and upper level atmospheric dynamics associated with the storm system suggest the potential exists for a strong low level jet, which could push along the coastline on Tuesday into Wednesday.

Models which track the storm close to the coast, show a strong low level jet which could bring windy conditions to many areas. 925mb winds are pictured here. The red shading indicates 55kt winds. The pink shading off the NJ coast indicates winds of 60kts or higher at that level.

Models which track the storm close to the coast, show a strong low level jet which could bring windy conditions to many areas. 925mb winds are pictured here. The red shading indicates 55kt winds. The pink shading off the NJ coast indicates winds of 60kts or higher at that level.

With a full moon and high tide cycle, the potential would exist for coastal flooding and some beach erosion depending on the exact track of the storm system. In addition, dynamic precipitation could bring very heavy rain to parts of the area for a prolonged period of time as the storm system tracks just to the east of our area.

As far as winter weather is concerned, this storm doesn’t look likely to bring widespread snow, sleet or freezing rain to the area — especially not to areas along the coast, or New York City. The best potential, if any, for witner weather would exist in the higher elevations of Northwest NJ and Southeast New York, where colder air may be able to work down and overcome the warm layers in the atmosphere as the storm moves by and provides dynamic cooling throughout the atmospheric column.

Still, a colder solution could come to the table if a polar disturbance to the north of the system gets involved — or the high pressure to the north trends stronger or farther south. At this time, however, that looks increasingly unlikely.

What uncertainties still exist with the storm system?

Anything and everything other than the idea that the storm will, in fact form. The track of the system will ultimately be decided by individual nuances in regards to the phasing mid level disturbances. And even after the phase occurs, mid level jet stream orientation and moisture dispersion will determine where the precipitation shield tracks and how heavy the rainfall is in our area.

The exact track of the system will also determine where the strongest low level jet tracks — and, accordingly, the potential for strongest wind gusts. Coastal flooding and beach erosion along the coasts of New Jersey and New York will also be determined by specific details in the storms orientation and track, which we ultimately won’t iron out for a few more days.

Canadian model ensembles showing many different storm tracks and locations for the storm system on Tuesday morning.

Canadian model ensembles showing many different storm tracks and locations for the storm system on Tuesday morning.

Obviously, a storm track closer to the coast will bring more impacts to the area including heavier rain, stronger winds and more potential for flooding. But a track off the coast could still bring impacts to our area as well as winter weather to the elevated areas of Northwest NJ and Southeast NY into interior New England.

Over the next few days, we’ll have numerous updates on the storm system — so stay “tuned” as our meteorologists continue to track and analyze the data. Be sure to keep an eye to our social media as we update those very frequently throughout the day.

 

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