NY NJ PA Weather Forecasts

Pattern Change This Week

10:05 AM

I want to discuss a few ideas for this upcoming week, as I will naturally be focusing on the short range the rest of the day. 

The pattern is changing, that’s for certain.  However, I think my idea of a moderation for the end of January into early February is going to be wrong.  Oh, there will be moderation this week, but the idea of a warm January and February that some had (not me, but some) is all but dead in my opinion.  Why?  Say hello to my friend, the negative EPO! 

As I was discussing a few weeks back, the winter pattern goes in cycles and the driving  force in the Pacific, which is supported by the placement of anamolies at the stratosphere, is the state of the EPO.  The monster block that formed in early January is also having some lingering effects.  The atmosphere tends to “remember” that influence and thus the Polar Vortex is in a much more favorable position, over Southeastern Canada rather than over central Canada. 

However, before I can get into all that, let me work on the next few days here.

The next and final disturbance for this trough will dive towards the Southeast coast by tomorrow evening and will support the development of a coastal low over the Southeast.  The trough will be lifting out of the Northeast in this time period, so the storm track is going to be too far east to do much for anyone north of Baltimore, however new President Obama will have to likely deal with some snow flurries in his speach and celebration on Tuesday night.

There will be some moderation in temperatures to near normal levels on Wednesday and Thursday while a new trough develops over the Plains.  The southwesterly flow will support a storm track from the southern Plains towards the Great Lakes for the end of the week, therefore any low pressure that tracks towards the forecast area will end as rain over the forecast area. 

The Arctic air returns for next weekend, and an interesting pattern will take hold.  The pattern will be what is called a split pattern.  The pattern will have several key features.  A strong upper low off the West coast will send disturbances through the Southern Plains and into the Southeast, while also aiding in building a ridge over Alaska.  The ridge over Alaska will support a continuous northwesterly flow into the central and eastern United States, which means storng Polar and Arctic air masses will have no problem driving towards the eastern two thirds of the nation.  The upper low over Eastern Canada will also support a storm track through the Mid Atlantic and Northeast.  Now, this pattern can produce favorable storm tracks for isentropic lifting events, but I wouldn’t expect a strong Nor’Easter out of this pattern.  This could easily feature a situation where the Mid Atlantic warms up ahead of a storm and then a significant cold shot or this pattern can produce a series of significant snow and ice events.  The question lies in how the two branches interact and while branch is dominant at what time.  These types of determinations can not be made by guidance nor forecaster in the medium and long range.  

So we are certainly heading into a cold and stormy pattern, whether that leads to snow as well is unknown.  However, what we do know is that no one should expect a warm end of January nor a warm start to February.

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