Image courtesy of Mark Vogan
As we progress towards September and autumn we have varying influences which play into our weather pattern over the forthcoming 3 months. El Nino being one of them and the likely reason for such a wet summer as well as the cold mode of the PDO and warm AMO.
Autumn of course is the transition period from summer into winter when days shorten and nights lengthen, when the leaves turn as warmth heads south and cold expands and works down from the north. It’s amazing how many google searches are showing up of folks wanting to know what this upcoming winter is going to be like. I think now more than ever, people are wanting to know what the weather will be in the longer term. Perhaps it’s as modern technology advances more and more and the influence and incredible communication we all have with social media sites such as facebook and twitter. The recent cold and snowy winters also may have played a considerable role.
September looks to remain unsettled but mild
As it stands right now, I believe the pattern will remain fairly unsettled with up and down swings in temperatures depending upon whether an Atlantic low is approaching, overhead or gone and we have backside influences.
The first half of September looks much like what we’re seeing right now and it could turn very wet during the third and perhaps 4th week in the month. Timing is tough but I can see where we may face more flooding issues and record rains. With all the cloud and damp, temperatures while by day may be cool. by night they’ll hold up. There will be spells of warmth and settled weather but like we’ve seen all summer, these are short lived.
The rest of Europe is likely to remain warm and fairly settled with high pressure in control through September.
October looking more settled, less rain with warm days, cold nights
October looks to be a better month with a fairly decent spell of more settled weather. With much shorter days and increasingly long nights, while days should be warm in the sunshine, perhaps to unseasonable levels, we should see chilly or even cold nights with frost under clear skies. This period of much more settled, mild weather should come with a period in which the NAO goes positive with a North Atlantic trough and ridging over the Northwest of Europe.
October may be a colder and more unsettled month for the rest of Europe, especially in the east where early season snowfall is possible.
November sees the return of wet weather, could be a very mild month and stormy!
Like we saw in 2009 with the El Nino in a similar state. The abnormally warm North Atlantic waters is likely to play a big role in rainfall as the chilly reservoir of air builds in the north and residual warmth holds firm over Spain and much of the Mediterannean. A large thermal contrast between Greenland/Iceland and southern Europe combined with a near neutral or negative NAO may support not only the return to very wet conditions but also stormy weather also.
El Nino years with waters as warm as they are over the Northern Atlantic Basin when an NAO is negative does tend to lead to well above normal rains and mild conditions. We saw this with November 2009 and I expect to see similar conditions this November also.
Does this mean a warm winter ahead. No not at all. Keep in mind how autumn of 2009 played out. Very wet Septembers and Novembers with a settled spell in October. This was followed by a bitter December through February spell that winter and I think we have a good chance at seeing similar this time around.
Image courtesy of Sealift (US Navy)
Excellent article as always, Mark! Looks like a very interesting period now until the end of the year!
Thanks, Edward! Yes. Interesting times for sure.