Thursday, September 5, 2013

2014 Winter Outlook: Expect Some Action on East Coast with Mild Conditions at Times

Below is my first forecast for the winter of 2014. The video will take a deep dive into the variables I am using for my forecast while the text summary below is more of a speed read. 

At first glance the Winter of 2013-2014 looks to be above average in terms of snowfall and slightly below average to normal for temps across the Northeast. I am basing my initial forecast on four major variables ranked in terms of highest impact on the winter season:

  1. Development of a weak El Nino (warm water off coast of western South America)
  2. A Warm Atlantic Ocean
  3. A negative Pacific Decadal Oscillation (cold water along the northeast pacific coast, with warm water further out to sea)
  4. Not Very Active Solar Activity (measured by sun spot activity)
All four of these variables should lead to high latitude blocking across Greenland, and an active southern jet stream which in turn will create a storm healthy environment for the Northeast at times. I do not expect a brutally cold winter. Instead I think we will see wide fluctuations between below normal and above normal temperatures as the Jet Stream position will vary. The long term climate models also support my thoughts which I will show graphically. Starting off with the Climate Forecast System model, here is what it is projecting for temperatures this winter...

As you can see it is predicting above normal temps for the western US and seasonable to below normal for the East. This is indicating a ridge in the jet stream to the west and a trough to the east. This jet stream pattern as I mentioned is going to be largely influenced by what the water temperature profile will be off the South American Coast. Here is what current models are predicting for how warm the water will be in that region..

By the DJF (dec,jan,feb) time period most model guidance is predicting a weak El Nino as shown by the y axis variables over 0. Here is generally how a weak El Nino effects the jet stream

Combine this with the other variables I mentioned (warm Atlantic, low solar, negative PDO) here are all the years I have found in history that had many of those variables present and what the atmosphere looked like in those years..

Red indicates high pressure and a Ridge in the jet stream and blue indicates lower pressures/colder air/through in the jet stream. You can see that these winters had the tendency for low pressure to develop over the eastern part of the US, high pressure over Greenland (essential to big Northeast storms) and possible ridging in the western US. The lower pressure shown over the gulf of Alaska is not ideal, as it can result in a warm zonal flow at times, but I think taking all factors into account we will have periods of activity. With that being said here is my forecast for the jet stream this winter..

I am predicting we will see a active northern and southern branch, that will merge when we have ridging in the west (shown by dotted blue lines). At times I do believe we can see zonal flows (flat jet stream) which will cause some warm spells. Add everything together and here is my initial Winter Forecast:



When it is all said and done I think we will see two Major snowstorms this winter one occurring early in the season the other around mid to late Feb. In between, I expect a few light to moderate snow events as clipper systems will swing down from Canada. Do not be surprised tho if this winter comes in sprints meaning we have weeks of warmer than normal temps followed by very cold and snowy periods. 

Thanks for checking in, I will release the final winter forecast in November and update if necessary. The one factor that can bust this forecast is if the El Nino becomes too strong, but I don not see that occurring at this time. 

In the meantime follow me on twitter @weatherwilly

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