In today’s post I wanted to take a first look at autumn and also discuss more winter thoughts too.

Here’s a look at the Jamstec for autumn and winter.

The Jamstec is going with a ‘wettish’ autumn but dry winter.

Sep-Nov

Dec-Feb

It’s looking very dry throughout the period for the western mainland of Europe.

What’s interesting is it has a warm autumn over the majority of Europe including most of the UK (Expect NW) and a warm autumn & winter for Greenland but cold Western Europe. Systems crossing a cold North Atlantic?

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As for the CFSv2, well it continues to show a North Atlantic trough/Europe ridge pattern reflective of the cold North Atlantic (lower heights) and a dry continent/warm Med Sea (above normal heights).

Heights tend to increase through the winter months over Hudson Bay extending into the Northwest Atlantic. The model suggests that this pushes the mean trough east into Northwest Europe which may support colder systems and therefore a ‘colder Atlantic pattern’ across Ireland, UK and near continent. Like last winter, I suspect there’s ‘spells of snow and cold’ in between longer spells of mild. Plenty of storminess too.

A lot I believe is going to ride on what kind of weather pattern we have over North America and there’s a great deal of uncertainty here too because of the El Nino. For last winter in particular, the air masses were so cold over eastern North America and with a colder-than-normal Atlantic, we managed to get some decent snow and cold on this side but if we happen to have a less cold E North America, I question how cold the systems may be once they’ve crossed the Atlantic. Looks very like we’ve another firmly positive NAO winter coming up but that doesn’t necessarily mean a non-winter.

Also, we had an abnormally strong trans-atlantic jet stream 2 straight winters in a row, caused in part by the thermal gradient over North America (very cold over US, warm over Gulf/Caribbean), helped also by a large contrast in SST between north and south, a warmer eastern US could suggest a weaker jet. This could mean 2 things, less intensity of storms for the UK or even a greater chance of height rises over the Atlantic or Greenland which could support a colder pattern for the West of Europe.

Here’s the CFSv2 precipitation anomalies September through February next year. Note it has a fairly wet outlook overall and most of the time it’s got the heaviest precip in the west. This tells me that the model sees a predominantly ‘westerly/Atlantic’ pattern.

Sep

Oct

Nov

Dec

Jan

Feb

With the below maps, I’ve chosen to show the North Atlantic view because I wanted you to see where the model positions the trough/ridge. That’s important.

CFSv2 500mb anomalies September through February.

Sep

Oct

Nov

Dec

Jan

Feb

Even with the warmer, stronger El Nino years when the North Atlantic was warm too, i.e 1997-98, winters tend to be coolest late in the season. Will show the 2 metre temperature anomalies autumn through winter again in the coming days.

No post tomorrow (Sunday), next update will be available Monday AM.

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Tags: autumn forecast 2015, europe winter forecast 2015, uk winter forecast 2015-16, winter 2015-16