We continue to look for clues regarding El Nino and the impact it will have on the up coming winter of 2015-2016. Franly I have always been very uncomfortable about trying to figure out things 3 or 4 months in advance because the one thing I have learned over the years is that it is never always the exactly the same. There is always at least one wild card in there somewhere that will throw off the long range one way or the other. Let’s take a look first off at the probably overused analog which is 1997-98
I would have liked to have used identical maps but you have to make due with what’s out there so let me take you through this. Red is above normal and this pretty easy to sea. I am comparing here August 1997 vs August 2015. The match up is prety good at first glance but there are some differences in the sea surface temperature pattern that should be noted. The waters off the East Pacific are both much warmer than normal, by as much as 5 degrees in the brightest red in 1997 and in the August 2015 observations.
However there are standout differences. The first being in the northwest Pacific where there is a cold pool of water which appears less extensive than it was back in August of 1997. Another difference is on the North Atlantic side where water temperatures were much above normal in August of 1997 but are actually below normal in 2015.
The other El Nino year that gets tossed around is 1982-83 and there are big differences between that el nino and the 1997-98 el nino.
Note the huge differences in both the Pacific and the Atlantic. Much of the Pacific north of 20 degree north is seeing below normal temps while much of the Atlantic ocean was seeing below normal temperatures as well! That particular winter had an early start followed by warm temps and the a rather active February with the Blizzard of 1982-83. 1997-98 of course was a dead winter for much of the northeast and middle Atlantic States. I remember driving up to New Hampshire in early January where there wasn’t any snow anywhere and I only managed to see flurries!
Okay back to El Nino. Let us look closer at the Atlantic Ocean in August 2015. The cold pool of water south of Greenland is huge. Also the Central and Tropical Atlantic ocean waters are above normal vs the 1982-1983 map. The above normal pool measures up well to the 97-98 el nino in the Atlantic Ocean south of 35N-40 N but north of there it is completely different. The Pacific side in August of 2015 matches up better to 1982-83 than does 97-98.
What to make of all of this beside confusion. First off the fact that everyone is keying on 1997-98 makes me want to discount it completely. In the weather world like the stock market you don’t want to be with everyone else on the same side of the trade. When everyone is on one side it pays to look at the other. Secondly that cold pool south of Greenland is a standout. Is this an indicator that that the North Atlantic Oscillation (NAO) which has not been a player for much of the last 3 winters will be a player this year due to the decline in North Atlantic Ocean water temperatures? This is a big wild card and I think it is the wild card that very few people are talking about and I believe may be the one we should be focusing our attentions on more so than El Nino. The second issue is in regards to the warm water pool off the Pacific Northwest which has been there the last 2 winters and is still there. It has been suggested by some that re-curving typhoons in the Pacific could drive development of strong extratropical storms in the Gulf of Alaska which could cool that pool of water down. However we should point out that while many models have been showing recurvature, few typhoons have done so at least so far.
Here is the other caveat. We know what we know and see right now. Will this be the profile come November and December? So far there has been little to suggest any large scale changes but that may not be the case a month from now. This is not an instantaneous process with regards to forecasting but a continuous and ever changing one. There are just way too many what ifs!
Now what of the arctic sea ice and the relationship between Siberian snow cover rate of growth. This is a recent theory that has been an interesting indicator. Last year we had the second strongest rate of growth on record however the conclusions about how it would play out were incorrect. It is like getting something right for the wrong reason.
Arctic sea ice as of today has shrunk to the 4th lowest level ever measured, though it should be cautioned that they have only been measuring it over the last 30 or so years. The open Arctic ocean creates an increased pool of available moisture for storms to tap and produce heavier than normal snows in the arctic regions of Alaska and North America. So far the snow cover is hardly there except in a few isolated spots however it is October’s rate of growth that we will be watching. All things being equal this should lead to greater snow growth rates this October but all things in weather are seldom equal. There was no el nino last year. It will be interesting to see how this plays out over the next 6 weeks.
Here is the bottom line. We are no closer today then we were 2 weeks ago on the answer to the winter weather question. I doubt that we will be 2 weeks from now or even 6 weeks from now. There are just way too many variables to consider and they are variables that are constantly changing. Nor should we draw any conclusions by the current above normal temperature pattern in the east, or the lack of hurricane activity in the Atlantic, or that the acorns from oak trees are all over the place and coming down early. That could be the result of hungry squirrels. The bottom line is that we will continue to revisit this issue every couple of weeks to see where we are going. Remember folks weather forecasting is more a journey than everything else with something in every corner that could change any outcome.
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