Winter 2017-18: Discussion

I'll go over it all tomorrow .

Ok so I'm going to be doing a couple of posts on different aspects. In the ENSO thread here: http://www.boards.ie/vbulletin/showthread.php?t=2057713492, I've been discussing about Winter 2017/18 on what it could be like given the possible outcomes of ENSO.

I will go over what I have been talking 'bout since I made that thread in regards to Winter 2017/18. So yes, the topic of this post is ENSO.

Back in the Spring, it looked like we could have been heading into an El Nino event and quite a moderate one at that. Normally, a moderate El Nino is actually a very good sign for a cold Winter. Winter 2009/10 had a moderate El Nino - though there were plenty of other factors at play also. This is my reanalysis on historical moderate El Nino winters:



The reanalysis clearly showed a high chance of a cold Winter with a southerly tracking jet stream and very intense Northern Blocking as the winds go clockwise into an easterly direction.

As we eventually got past the Spring unpredictable barrier, the models were pointing more towards a weak El Nino and then ENSO neutral. I started looking at weak El Nino winters then, this is my reanalysis for them:



The reanalysis shows plenty of Northern Blocking but the jet stream is going through the country. This is very evident of Winter 2013/14 which had a similar chart. A weak El Nino is not a good sign at all for Winter. This was the trend on the models for a while then until late June and July. I decided to look at weak El Nino winters that were preceded by weak La Nina winters because as we know, Winter 2016/17 was a weak La Nina winter.



This was even worse than the previous weak El Nino chart as the jet stream is on a perfect westerly regime. With the very low heights and the intensified westerlies, it would be very stormy.

Fortunately, there was also the chance of ENSO neutral so I had a look at ENSO neutral winters that were preceded by weak La Nina winters.

This is the reanalysis of said winters.



It shows clearly Northern Blocking. It also shows a trough to the south with the winds coming in a clockwise direction from an easterly. This means it would be a rather unsettled but cold Winter. If the cold is intense then a very snowy Winter. This is a beautiful chart if that's the case.

The Pacific then started to significantly cool down during late June and July. As a result, the models reacted to this cooling and then started showing the possibility of a weak La Nina - once again for 2017/18. El Nino by this stage was dead and long gone.

I looked at the weak La Nina winters that were preceded by weak La Nina winters then. This is the reanalysis of said winters.



This was quite similar to the ENSO neutral chart but even better! It shows a very January 1982 or December 1995-esque kind of setup. This means extreme cold is possible - both months got down to -27c in Scotland.

What I think is the most possible outcome for ENSO is ENSO neutral. However, as can be seen from last year's extremely weak La Nina, a weak La Nina is certainly possible.

I will explain how similar 2012 is to the situation now in regards to ENSO in a post soon.

If it so not going to me snowy and cold well then Mild and Dry will be better off

Now onto the North Atlantic and the NAO. As you can see from the current Atlantic SST anomalies, the Atlantic is in quite a mix with some cold blobs here and there but also some warm bands. Near the end of July, I looked to see if there are any matches in regards to the distribution of the Atlantic SST anomalies. There have been some matches though of course not perfect matches - see them below.



2016:



2010:



2005:



2004:



2001:



Overall, I think 2010 provides the best match.

The NAO in May is considered to be a factor in predicting the Winter. This is because due to research, there seems to be a correlation between the setup in May and Winter. May is normally the quietest month in terms of westerlies or the jet stream during the year in Ireland. May 2017 had a negative NAO throughout the month as can be seen from NOAA's chart:



However, there was no tripole. If you don't know what a tripole is, here's an example of a tripole in May 2010. Of course, we all know what happened after that - the December to remember of 2010.



This was the SST anomaly chart for May 29th 2017 (it's updated every Monday). As you can see like I said, there is no tripole as the bands are as follows: Cold, cold, warm when you want Warm, cold, warm so we were very close to a tripole.



However, in May 2009, there was no tripole either. The Met Office predicted as a result for Winter 2009/10 to be a mild one. Of course, they laughably failed on this prediction and it was the coldest Winter since 1978/79. In May 2009, we weren't even close to a negative NAO or a tripole - then the Winter of 2009/10 had a record breaking negative NAO.

Gonzo wrote: »

by water freezing I take it you mean rivers, small lakes and harbours. It rarely happens in this country. Last time that happened was 2010, and before that I can't even remember, maybe 1991.

I mean for something like this in my back garden.

https://s-media-cache-ak0.pinimg.com/originals/de/8b/fc/de8bfc6768ec6f4af7dab1c78abde325.jpg

Here's how the Winter is looking like today as courtesy of everybody's favourite model, the CFSv2 :rolleyes:. The three monthly anomalies show December-January-February as an option but for the individual months, we only have December and January to go off of right now.

Winter overall - Very wet, mild and stormy.

December - Looks to be quite a wet and mild one. Not as extreme in either case as January looks or even the Winter overall but nevertheless, still miserably wet and mild.

January - Exceptionally mild and wet. Looks like a record breaking warm January and wettest January since 2014, even more so than January 2016.

What a terrible outlook!

I'm expecting a truly boring winter after what has been a truly boring summer with nothing of note. Last winter was like a constant October and I expect the same this year.

The whole of this summer has been like a constant October too. Ireland might as well just rename the word climate to "constant October". For that's what it feels like all year round these days

Our autumn weather in the last few years has been quite good from what I remember....our autumn weather was usually alot wetter/stormier than it has been recently...

sryanbruen wrote: »

Autumn 2014 was quite wet after a very dry September. November 2015 was very wet and stormy. October 2013 was also wet.

I stand corrected:D:pac:

sryanbruen wrote: »

glightning wrote: »

I'm expecting a truly boring winter after what has been a truly boring summer with nothing of note. Last winter was like a constant October and I expect the same this year.

The whole of this summer has been like a constant October too. Ireland might as well just rename the word climate to "constant October". For that's what it feels like all year round these days

What do you mean by this 'cause on average, October is the wettest month here in the east of Ireland?

Well, I live in Northern Ireland and this summer has been consistently below average temperature wise. Consistently between 1 and 3c below average which translates to the temperature you would normally expect in October (14c to 18c maxes).

Also, in July we had 40% more rain than the average for July. So yes, it's been more like October. Wet! That has been the theme for many July's here. Well above average rainfall.

In fact, summers have become so consistently bad here since about 2006 that most people now think of the March to May period as our 'summer' as that period generally delivers better conditions that the actual summer does. its not just people into the weather that think that way either. Anyone you speak to feels the same about it.

glightning wrote: »

Well, I live in Northern Ireland and this summer has been consistently below average temperature wise. Consistently between 1 and 3c below average which translates to the temperature you would normally expect in October (14c to 18c maxes).

Also, in July we had 40% more rain than the average for July. So yes, it's been more like October. Wet! That has been the theme for many July's here. Well above average rainfall.

In fact, summers have become so consistently bad here since about 2006 that most people now think of the March to May period as our 'summer' as that period generally delivers better conditions that the actual summer does. its not just people into the weather that think that way either. Anyone you speak to feels the same about it.

Ok, I was just very confused over the odd comparison.

My 'hunch'* is that we'll have a colder than average winter, which does not necessarily mean that we will see significant or severe cold spells (but I'd not rule them out either).

Personally I am hoping for some proper storms this year, not these watered down, 'millennial' types that we have accepted as 'normal over the past 15 years or so, but something with a bit of 70s/80s/90s oomph.

* which is worth jack ****.