Potential increasing for Heavy Rain and Snow across the Mid-Atlantic early next week

There has been an interesting development among the latest forecast models today with the potential for a very complex storm system set to impact the Mid-Atlantic and New England early next week.  For one, the NAO is forecast to be negative and an arctic high is forecast to build over eastern Canada. The trough is forecast to become negatively tilted and if future runs begin to consolidate on more of a coastal track with colder air sliding further south, we could be talking about heavy wet snow in the higher terrain west of the big cities or possibly rain going over to heavy wet snow in the big cities.  As of now, the models favor rain in the big cities with the potential for heavy snow in interior sections but this is definitely not set in stone.

Here is the latest “Trend GFS” model (image courtesy tropicaltidbits) showing the last 5 runs of the GFS showing the potential location of the coastal storm on Monday at 7pm next week):

  • Notice that with each subsequent run for the same time frame (7pm Monday of next week) the coastal low pressure system has trended deeper (stronger) and further offshore.
  • Also notice the 1026 mb High pressure system anchored over eastern Canada (the blue H)… if future model runs continue to deepen this system colder air could get drawn closer into the storm system setting up the stage for a heavy, wet snow in parts of the Mid-Atlantic and New England. 


The NAO is going to be in its negative phase early next week (January 20th through the 24th) before it trends neutral or positive late in the week.  Because of this, I think that we need to focus on the early week system more than what I originally thought might be a late week system.


The next image shows the GEM model (Canadian) with a similar trend:

  • The Canadian model has really jumped around with low pressure placement but in its most recent run shows a 984 mb coastal storm sitting just off Virginia Beach.


  • The problem I am seeing is a lack of cold air (for now)… but like I said if future trends scoot this system further off shore (a Cape Hatteras to Cape Cod track) and colder air gets pulled into the system (due to the blocking I mentioned earlier)… the forecast has a lot of time to rapidly change to a colder solution.


Finally the European Ensemble Mean Surface Low Pressure Anomaly:


The European Ensemble model (image above) is showing one heck of a coastal storm (deep purple colors with a “990 mb” coastal low sitting just off of the Del-Mar-Va coastline) with blocking out ahead of it stretching from north-central Canada eastward into Nova Scotia (bright orange colors).   Blocking is what we need to slow these systems down, causing them to rapidly deepen before they can quickly skirt off to the northeast.

This system currently has my interest peaked and I will be updating with future posts as more data comes in.


Lastly, I would like to thank Chris Fukuda, who calls himself an aspiring photographer (I would argue he already is an amazing photographer) for graciously allowing me to use several of his pictures for my header images on my website.  You can follow Chris Fukuda’s on Twitter (@Chris_Fukuda).  Thanks Chris! 



3 thoughts on “Potential increasing for Heavy Rain and Snow across the Mid-Atlantic early next week

  1. For now, the odds are in favor of very beneficial heavy rain for the metro with the potential for some snow in the higher elevations. If the storm does indeed track further offshore, then there could be some wet snow closer to the cities but for now that is a long shot. I’m hoping the ski resorts can get several inches of fresh snow pack.

  2. Didn’t think such a trend would show up but here we go! I’d like some snowpack around here. Could this mean snow for our area if the storm skooted out offshore?

  3. This could almost be like a spring snowstorm where the cold air is not necessarily advected in, but comes down from aloft with the upper low if the precipitation is heavy enough. Hopefully, we can also advect some cold air from that high as well!

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