Thursday, November 7, 2013

First Look at Potential East Coast Storm

We have a very intriguing weather scenario that the models have been suggesting will set up for the latter part of next week. Before I get into any details I want to say we are still 7 days away which makes my projections far from a forecast at this point. The modeling first hinted at this two days ago on the European and now that most major models are in agreement on some storm forming, so I will break down the details. Most likely by Saturday I will start to take a stand on what I think will end up occurring. Until then lets look at whats projected to happen..

Above is an image I modified from the upper air pattern of the European model. Blue is low pressure areas and jet stream troughs (where storms like to develop) and orange and red are jet stream ridges (indicates high pressure, no storms.) This model is showing a very deep storm developing over the east coast as shown by green. The key however is understand why this storm develops so deep as shown. The factors involved are labeled on this map.

  1. Massive ridge over the Bering Sea causes a sharp trough underneath just off the west coast.The deep trough off the west coast then causes a massive ridge to develop over the central part of the country as shown above. Downstream this results in a sharp east coast trough. A rule of thumb is a trough just off the west coast usually results in a trough over the east
  2. Energy from northern Canada then travels around this central ridge as shown with the curving yellow arrow above and redevelops along the east coast bombing out a major storm.
  3. As this starts to develop that big central ridge then migrates to the east blocking the storm as shown below causing it to reach peak intensity over our area.

A setup like this is not very common which is why this forecast will be tough. Any slight change in the position of any of those variables I mentioned above changes the track of this storm. So now lets look at the model spreads at the surface. Top is European,  bottom is GFS

As usual there is a model spread and the GFS is showing its bias of shooting storms out to sea. At this point however both solutions are equally possible. Last night both the GFS and European gave the whole mid Atlantic over 10 inches of snow and since they they have spread out. Take the above European solution and move it in between this model spread and you have one ugly early season mid Atlantic snowstorm. As I said I am not ready to make a call on this yet, but with the water being so warm this time of year out in the Atlantic, the middle scenario needs to be considered. 

Just for fun, here is what last nights European model printed out for snowfall (click to make bigger)...

What I am confident in is that this setup will produce very bitter cold air for this time of year late next week regardless if this storm effects the Northeast. So bitter in fact that it might bust my November temperature forecast. In any event with have a big weather item that is now worth watching over the next 7 days I will be updating this blog daily with new developments. In the meantime follow me on twitter for more frequent updates on this situation. 

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