Monday, November 12, 2012

Long Range Lookout: Stormy Start To December For East US

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I am seeing a very stormy pattern emerging just after Thanksgiving and into the first days of December. Let's go into why I think this will happen.

A rule of thumb in forecasting the long range is that nearly everything has a correlation with something else (i.e., Factor 'A' has a correlation with Factor 'B', which has a correlation with Factor 'C', and so forth). One of these correlations includes East Asia. East Asia? Yes, East Asia. It has been shown that there is a 6-12 day gap between what happens in East Asia and what then happens in the East US. For example, if there were a big warm spell in East Asia thanks to a monster high pressure system, that same occurrence would happen in the East US 6-10 days later.

The above images are of 500mb height anomalies from 3 different forecast periods of the GFS Ensembles (GEFS). If you look in the upper left hand corner of these images, you will see a shade of blue encompassing none other than East Asia. I think you know what'll happen next.

If we apply this 6-12 day rule to the forecasted troughs (low pressure systems) in East Asia to the East US, we are likely to see a very stormy pattern begin immediately after Thanksgiving and persist through the end of November into December. This stormy pattern will bring unwanted troubles to the areas still reeling from Superstorm Sandy. The 'good' news is that this stormy period will not have any extreme storm systems like Sandy. However, bouts of heavy rain and snow are possible, if not likely, for much of the East going into the first week of December.


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