Did 2016 Super El Nino & Cooling Atlantic lead to the sweltering summer of 2018?

Written by on August 13, 2018 in Rest of Europe, United Kingdom & Ireland with 0 Comments

There’s little doubt that many will be asking why 2018 was such a warm one across the Northern Hemisphere.

I believe it’s very likely down to the response and lag of the Super El Nino which peaked during the winter of 2015-2016 combined with the cooling Atlantic basin.

 

El Ninos typically release heat from ocean to atmosphere but super El Ninos have much more dramatic global implications not just during the event but even a couple of years after.

The warming of the oceans release water vapor and this essentially helps enhance cloud formation and therefore allows less outgoing solar radiation. The full effects of a Super El Nino sometimes takes a couple of years to show it’s true response.

In terms of the European heat, the El Nino may well have played a role but the bigger role may have come from the cooling of the Atlantic with textbook horseshoe of cool extending from south and surrounding Greenland down the west side of Europe and NW Africa and extending out across the tropics.

Cold AMO’s (Atlantic multidecadal oscillations) support drier summers for the UK and Western Europe while warm AMO’s lead to wetter.

The cold February, March helped dramatically cool the waters surrounding the UK and Iberia but the cooling has been on an Atlantic-wide scale which has bigger implications of the upper air pattern.

Cooler oceans lead to less water vapor release and therefore can lead to less rainfall. A highly blocked upper air pattern during spring shut off the Atlantic from Western Europe and the cooler than normal waters extending from the Norwegian Sea down to Bay of Biscay and points extending all the way to the Cape Verde allowed higher than normal pressure to persist which in turn allowed the ground to dry out.

Cool surrounding waters and dry ground eventually leads to warmer than normal surface temperatures and that’s exactly what we got starting over Ireland, Scotland, Denmark and right across Scandinavia. As the summer progressed, so the heat and drying out process extended further south over England and France.

Drier air aided by a cool Atlantic and dry ground allowed unseasonably dry, stagnant air within high pressure cells to heat.

Indeed the persistent hot sun and lack of wind has helped dramatically warm the surrounding waters and it’s now well above normal.

So, while there’s likely other factors, I do feel the cool Atlantic and response of the Super El Nino helped produce a summer which has rivaled the UK and Europe’s warmest and driest in history.

This is not my theory but many other scientists theory on the lasting effects of ocean to atmosphere feedback response.

Now that the pattern has broken down and the Atlantic flow is back, we could find an increasingly wet autumn on the way given the warm waters.

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