Winter 2018/2019 - General Discussion

Ayyyyyyyy, I was waiting for this. Wondering when it was gonna start.

Well to start it off, we have a stonker of an ECM seasonal model update for August! Plenty of easterly and northerly incursions for October, November, January and February on it! I can almost smell the snow now. February looks exceptionally blocked.

It better not be snowy for my birthday the one time I'm away when I'm off to New York!

Bank these ECM charts please.

Danno wrote: »

What do you see are the issues? And how are they going to play out?

Replying to this here Danno as it's the Winter thread after all. First, let's look at the current state of the north Atlantic. This is the latest global sea surface temperature anomaly from NOAA for 16 August 2018. I have divided the North Atlantic into three because this is how we see if the profile is favourable to negative NAO which is the key to cold and snow in our country - though there can be cold and snowy months with positive NAO such as January 1984 but those kind of months are few and far between. The North Atlantic is in a positive NAO state with bands of cold-warm-average. In May, this was cold generally though warm over to the eastern seaboard of America and the cold anomalies were in the shape of a horseshoe which led to the hot Summer as it promoted blocking over Scandinavia and from the Azores to us, 1976 featured a very similar profile. This is a clear sign of cold AMO. However, since May, the tropical Atlantic has warmed up significantly but still only average by this stage of August and the peak of the Atlantic hurricane season is just around the corner - usually mid September - so expect some hurricanes to form if the Atlantic continues to warm up and vertical wind shear dies down. If an El Nino does take off, do not expect this to happen as vertical wind shear continues to increase with El Nino which in turn leads to a decrease in hurricanes.

An active Atlantic hurricane season is one of the things we look at for Winter as it dumps a lot of warm water in the North Atlantic Ocean which can then be advected into the North Pole and promote northern blocking. 2010 was an active hurricane season. 1995 was an active hurricane season. 1887 was an active hurricane season. These are three examples of years that had active hurricane seasons and were followed by cold winters. However, it's not impossible to receive a cold Winter with an inactive hurricane season, 2009 was such an example and was followed of course by 2009-10. 2009-10 was an a moderate El Nino Modoki and as a result had increased vertical wind shear which led to the inactive hurricane season but as it was El Nino Modoki, we had a cold Winter. El Nino Modoki is very good for cold Winters in the UK and Ireland! The El Nino which is forecast by the models and agencies this year is a modoki and I expect it to be a modoki but there is uncertainty on if it will reach El Nino threshold which is 0.5c or more above average. 1990-91 was an El Nino Modoki but did not reach the threshold though it was a cold Winter with a notable cold and snowy spell in early February 1991. Anyway, I'm going off on a bit of a tangent, thought you'd might like that extra info with this post.

Another thing I'd like to point out is the Norwegian Sea - notice the significantly warmer than average SSTs there. Very similar to last year! Now look at the 500mb height anomaly reanalysis for 2017-18, there was plenty of northern blocking there which we theorised last year there to be as a result of the state of the Norwegian Sea, similar to come this year?





The SST profile in the Atlantic we want to see is one like this from 14 December 2009, bands of warm-cold-warm. What is the least favourable for a negative NAO in our current SST profile is the cold anomalies to the south of Greenland, we would want to see them disappear by Winter time and not to mention, the warm anomalies off the coast of America. They are two problems with the current state of the North Atlantic which are not favourable for negative NAO especially with a more powerful Polar Vortex as Winter gives. Things can change like they have since May as the Atlantic is more favourable now than it was in May but it's getting kind of late especially as it takes quite a bit of time for the temperatures in the North Atlantic to change unlike say the Irish Sea or the North Sea. Nevertheless, in spite of 1976 being similar to 2018 in terms of the Atlantic SST profile, 1976-77 was a cold Winter with a cold December and January but mild February.

The NAO forecast from May was for positive NAO in Winter 2018-19 using the UK Met Office's methodology but don't think this is the be all because the Atlantic was in a positive NAO state in May 2009 which led to the UKMO forecasting a mild Winter for 2009-10 - see SST chart below for May 21st 2009.



The Atlantic SST profile was in a big mess in May 2009. It didn't know what it wanted to do.

Would that Siberian high mean settled/fine weather for us ?

Sycamore Tree wrote: »

Will it be snowing in Galway at 3:25pm on January 11th?

Yeah I'd say so!! Get the bread in!

Loughc wrote: »

I'm stockpiling Brennan's Bread as we speak....

For the love of god, don't forget the tayto crisps. When the power goes, crisp sambos will be all we have.

.... showers turning wintry on northern hills at the weekend!

White Clover wrote: »

Would that Siberian high mean settled/fine weather for us ?

The main point I was getting at (considering this is the Winter thread after all) was that it's very early to be seeing a Siberian High on European charts and some notable harsh Winters have been recorded with a Siberian High appearing this early such as 1946 and 2009 the example I gave (although they featured two very different Septembers :P, 1946 was very wet and cool with a harvest emergency whilst 2009 was a huge relief with very dry and pleasant conditions following one of the wettest Summers on record). It's certainly something to watch.

Whilst that itself might not be a clear sign of settled weather for Ireland, the chart from the model shows a blocking area of high pressure over top of the country at the end of August into the start of September. This continues to be the case on the latest models but exact temperatures, high pressure alignment etc are to be revealed. That chart I showed would suggest low 20 temperatures widely with fairly low humidity and good sunshine. September 2009 featured a very similar chart by the way when it became very sunny for around 5-6 days especially in the west. So there might be some good news for you if you want settled weather. We'll be keeping an eye on the situation in the model discussion threads.

In terms of the Winter discussion today, I'll be giving a solar activity special.

I remember this post from last winter:" Have you ever looked out the window at snow and suddenly got a craving for bread"
There is always an sound explanation for hysteria. This poster has wisdom!

As regards this winter, the Liffey will freeze and robins will be knocking at the door to come inside.

Oneiric 3 wrote: »

To get us in the mood:

If we do get a severe cold snap this winter, I honestly hope it is early in the season. While the spell early last March was acceptable, it occurred too late in the year. Either way, I hope this year is 'the one' for record breaking storminess. It will be such a pleasure to experience after this long long, endless Summer.

This should help even more

Japan getting frosty early.....earliest on record! Same in Georgia (the country). Fill your wood store.


http://www.investmentwatchblog.com/earliest-ever-recorded-snow-in-japan-with-august-frosts/

sryanbruen wrote: »

I believe 2019/20 holds the best potential for severity of cold/snow

Out of interest, what leads you to say this so far in advance, regarding 2019?

One thing which gives me hope for this Winter is that the last time we had a deep cold spell early in the year / towards the end of a Winter was 2009/10 in and around New Year and again in early February 2010 - and we all remember how the subsequent Winter 2010 turned out

https://twitter.com/BruenSryan/status/1032775614036697088

nacho libre wrote: »

I keep forgetting, was it winter 2009- 10 that didn't have a ssw, or was it the winter of 2010-2011?
Also, what year was it that had a strong ploar vortex, yet a potent easterly still occurred.

2010-11. 2009-10 had a SSW in February.

2007-08 I think you're referring to.

nacho libre wrote: »

oh i see. My memory is getting worst:o

To be honest i doubt we will see scenes like last year for many years to come. The depth of snow was truly remarkable. If we got half that amount and a protracted cold spell to follow,preferably at the optimum time(January) for minimum night time tempertures and daily maximum records to be broken

I said the same in a post on the previous page, I do think 2010 levels are very achievable though.

One of the more forgotten cold spells was that of February 1969 which had decent snow showers and the air minimum temperature got down to as low as -17.1c (and -17.0c on the previous night) on February 17th that year at Claremorris. December 2010's minimum was only -0.4c lower with -17.5c. February 1969 was amazingly around solar maximum and came after a January that was mild but had a negative NAO/AO. November 1968 had a Canadian Warming.