EL NINO GONE BUT WARM POOL IN GULF OF ALASKA RETURNS, COLDER US WINTER?

Written by Mark Vogan on September 20, 2016 in Summer 2016, United States of America with 0 Comments

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It should be of no surprise how warm last winter panned out not just for the United States or Europe but for much of the Northern Hemisphere given the strength of the El Nino. As is the case when you get a super El Nino, it takes over the global atmosphere with warmth circling the globe, breaking records left right and centre.

Last winter’s forecast was tricky given the presence of the so called North Pacific ‘warm blob’ but this year is also tricky. I should rephrase, last year shouldn’t have been tricky but this year is given the increased warming of the Gulf of Alaska and cooling towards the Nino region. The two previous winters prior to last year saw record cold with the first year focused on the Upper Midwest, the second year further East. The reason for these back to back warm winters can be directly attributed to the warm pool or warm blob over the North Pacific which allowed a huge, semi permanent wintertime ridge to develop, forcing sub-tropical air to reach Alaska and the western Arctic.

The exceptionally warm water which extended down the continental US West Coast and south past the Baja of California into the equatorial Pacific counteracted any feedback from the warm water which drove the previous two cold winters and forced more ridging and warmth further south and east over North America. The El Nino flooded the continent in warm air which essentially shaped the 2015-16 winter.

So what about 2016-17? The waters down the continental US West Coast have cooled while slightly warmer than normal still (for now) off the Baja and nearer normal into the Nino region. With the warm pool regaining strength over the Gulf of Alaska and cooling further south, could the winters of 2013-14, 2014-15 make a comeback for the Midwest and East in 2016-17?

Credit: Tropical Tidbits

One important factor in what could help the upcoming winter turn colder is if the La Nina fails to fully develop and the ENSO holds neutral. According to more recent long term model runs, that’s a real possibility.

Another aspect I wish to add is the abnormally warm water up the East Coast, this is likely to hold a warm pattern well into fall, possibly November but cold is likely to arrive in the Rockies in October, Plains November, Midwest December and not until January for the East.

Of course the Atlantic equally plays a significant role and I shall look more at the Atlantic’s potential influence in the coming weeks.

As well as the ocean and it’s heat content and distribution, there are other important factors to consider including building Eurasia snowpack and extent during particularly October. These are all aspects I will be looking at very carefully over the next few days in the run up to my winter forecast which will be published November 1.