Latest UK Winter 2017/18 Weather Forecast Update: in the last update we discovered that the QBO is supportive of a cold winter this season in the UK. We will now go into some other variables that help us forecast winter weather conditions in this country.
In the pacific we have ENSO, El Nino Southern Oscillation, oscillations between El Nino (Warm central Pacific) and La Nina (Cold central Pacific). Earlier in the year it was thought that an El Nino was in store for the upcoming season, however the forecasts from the long range weather models have shifted further and further towards the idea of a La Nina being present for the winter season.
There’s no definite trend between a La Nina and El Nino for the British Winter. If anything, both a strong El Nino and La Nina ramp up the strength of the jet stream, however a weak or neutral ENSO state (both ways), has very little affect, and that’s when we turn to other factors. The fact we forecast to be in a moderate La Nina by December, and with the sea surface temperatures starting to reflect such predictions, can perhaps put sway towards a strong jet stream, impacting the UK with a rash of wind and high rainfall levels, however as mentioned, ENSO is a pretty weak signal for our side of the globe.
Strong Hurricane Season 2017
With the current Hurricane Season predicted to finish with above average activity, this bodes as another uprising signal for the winter period. So combined with weakening solar activity, easterly QBO and a strong hurricane season (which usually is a precursor for developing northern blocking), could we be on the verge of a shock for winter 2017-18?
The fact of the matter is that this certainly could happen, however each year something “new” pops up that seems to get everyone’s attention, and we usually learn that, that factor never helped our snow / cold lovers in the first place.
It takes something very significant, like the prolonged dip in solar activity at the end of solar cycle 23 (2008-2011), to bring significant and heavy winter weather into the UK. We will be at that point again in 2019-2022, which should bode well for perhaps the potential for some brutal winters. Up until then, a lot of variation winter to winter can be expected, perhaps staying on the “mild” side, however I would certainly not discount the odd potent cold snap. Stay tuned for more winter weather updates.
The Quassi-Biennial Oscillation (QBO), started trending negative (easterly) in the upper 50% of the atmosphere in April. The forecast is for a weak to moderate easterly QBO for winter 2017-18..
Here’s predicted solar activity right out to 2040, as you can see, away it slides. Winter 2017-18 is not sitting at the “perfect” place to get the cold & snowy winters that this will bring, however it could just offer a taste of what’s to come. By 2021 things could be very cold winter-wise indeed…..
Summary: past winters that had an easterly QBO combined with low solar activity produced a very variable result. So, as a result, I expect the most likely scenario to be a near normal season with huge weekly swings in weather conditions … more so I suspect some potent cold shots are entirely possible especially later in the season. Tune back later in September for more updates…
In my research, an Easterly QBO is generally 0.5C colder than a westerly QBO. With an easterly QBO upcoming for the winter ahead, this could mean we see our first cold winter, the chance is there, however it’s not set in stone..
Winter 2017-2018 is forecast an easterly QBO, however this does not guarantee a cold winter. We are at the side of the solar cycle generally not favorable for cold weather.
I have found that Easterly QBO winters on average are 0.5C colder than westerly QBO ones and 0.49C colder than neutral QBO ones. Because of this we can say that the chance of at least an “average” winter temp wise (which we haven’t had since 2014-15), is massively increased. In terms of a cold one, this is not likely because of where we are at the solar cycle.
Where we are at the moment in the solar cycle, is the same position on the previous solar cycle during winter 2006/7, so the Atlantic Jet Stream and Gulf Stream are still strong, a lag affect from solar maximum.
This also may explain why colder winters and ripe negative NAO tends to occur at the second half of the solar minimum rather than the first, it has a cumulative effect on the atmosphere.
This suggests that although winter 2017-18 isn’t likely to stand out as a cold or snowy one because the current phase of the solar cycle still supports ripe strong westerly NAO/jet stream strength, something of a confliction is occurring here because an Easterly QBO tends to increase the chance of a cold one.
The move into a strong easterly QBO phase plus a near neutral ENSO pattern may also swing us round to the other side of neutral at times, with some short sharp cold and snowy spells possible. As a result, I’d be surprised if temperatures deviate much from the average this winter as a whole, however some large week to week variations are possible with the northern half of the UK favored for any significant snow events.
The next update, a couple weeks down the line, will take a look at many more factors, and show what some seasonal models are predicting for the winter of 2017-18 in the UK, it will include much more detail on a preliminary forecast, and take a look at the individual months out to February 2018.
The cycle, has now trended firmly negative with a figure of -10.48 for July.
Though there are many caveats involved, the QBO is one of the main drivers of the northern hemisphere winter circulation.
An easterly QBO has the affect of weakening the polar vortex, especially when it’s combined with other closely related (more short term) drivers such as the MJO.
So in a nutshell, this is good news if a cold, snowy winter is what you’re looking for for 2017-2018 in the UK.
In terms of Canada and the US, view our US Winter 2017/2018 prediction here.
The caveat is though, that each winter (year) presents a new set of circumstances, atmospherically and oceanicaly, and long range forecasts are not yet advanced enough to accurately forecast winter weather.
Though it’s a long shot, we can decipher whether a cold, average or milder than average winter is more likely than the other.
We can also try and predict month to month swings in weather patterns based on long range forecast models and telleconnections. Nothing is set in stone, especially given the UK’s volatile pattern.
Winter’s 2013, 2014, 2015, 2016 and 2017 were all milder (2014/15 is an exception) than average, and westerly dominated.
Although being milder than average, winter 2016-2017 broke the wet and Atlantic based trend, with a drier than average season for most areas.
This means that the atmosphere is now in a state more susceptible to slight changes in the stratosphere, like a SSW which could trigger a cold, blocked phase.
These rather short lived phases are what produce cold conditions, for the most part are quite rare.
A combination of both low solar activity and a weak negative QBO could mean a weak and disorganized polar vortex this year, what this could mean for our winter, 2017-2018 weather, check back at the start of September for more information…
This means that although the polar vortex will have some strength, leading to some milder than average and westerly phases, there will also be enough “negative energy” to provide the odd cold pattern lasting 2-4 days at a time.
There simply isn’t enough negative energy in the mix to start forecasting cold, snowy winters at this time. Perhaps a few years down the line, there will be and we can start thinking of it being a greater possibility.
That being said, there’s plenty more to add to the mix over the coming days and months, nothing is set in stone and new information from the ENSO Pacific, Atlantic and long range models could swing this forecast in another direction.
Although for now, the emphasis is on the fact that although the atmosphere is definitely setting up for the expected 2018-2022 “negative era”, though changes will have not quite yet reached ground, “weather level”. Though I expect a few minor surprises in what could be a near normal winter.
During the last 2 decades, the notable colder and snowier winters have occurred during the late part of solar minimum, when the NAO is usually at it’s most negative, fuelling northern blocking and allowing the UK to experience just a slice of what our other northern friends, like Canada and Russia, experience.
The solar cycle is not optimal, however given an easterly QBO, some notable periods of below average temperatures are probable during mid-winter.. Read this article in full to see how long it’s going to be until the “proper” winter’s of 2009/2010 return..
At solar minimum, solar activity can drop to brutally low levels during which little or no sunspot activity can be observed for a long period of time – this is when we can expect the risk of severe conditions during winter in the British Isles – think December 2009 / February 2009. Typically, it’s during the later part of the sunspot cycle during which this occurs. For the current cycle this isn’t expected to occur for another 24 to 36 months, during which encompasses winter 2019-20 and winter 2020-21, which could well host some severe weather-like spells for the United Kingdom, however something else is happening in the atmosphere which may allow this to occur even earlier…
Winter 2017/18 is not positioned at the “optimal” phase of the solar activity cycle for ripe negative NAO. We are still as mentioned 18 to 36 months out. In the past solar cycle, winter 2005/6 and winter 2007/8 were at the same “Point” in the cycle and had some notable snow spells in the UK. There are obviously other factors that we include when issuing a forecast for winter. 1) Quassi-Biennial-Oscillation, an oscillation of winds in the highest part of the atmosphere that then penetrates down to lower levels, affecting the so called “NAO” pattern of the atmosphere.
Quassi-Biennial-Oscillation forecast for winter 2017/18:
Although the QBO should be in it’s negative phase for this winter, a very long and very rare lagged positive QBO during the past 3 years is uncharted territory for the QBO, therefore we can’t really use this as a factor with high confidence this year. However, it will be falling towards negative, which does support the formation of northern blocking, however that is probably offset by the current westerly QBO in the lower levels of atmosphere where is “unusually well established” due to it’s very rare longevity, which will still be present for the earlier part of winter 2017/18.
Although, by the end of the winter, both solar activity and the QBO will be in a slightly better position for negative NAO/ cold weather in the British Isles, so one thought is that the coldest weather of the winter may occur after mid January?
El Nino Forecast for Winter 2017/18:
A modoki El Nino or neutral ENSO is predicted for this year. The El Nino that was forecast earlier in the year has been offset probably by a cooling PDO, as we are now entering a cold PDO phase (PDO = Pacific Decadal Oscillation), and involves oscillation between a warm and cool phase of the Pacific sea surface temperatures. This is a “good” thing if you are hoping for a cold winter, but like all long range factors just a single factor alone will not allow something to occur, just that easily. This in a nutshell is one of the best patterns for Europe, as the affects of firing up the jet stream like a moderate or strong El Nino are not felt, and a weak, modoki El Nino does not fire up the jet stream nor heat up the Pacific.
So based on these very few factors analysed, one scenario I could think of is average temperatures and precipitation, which of course would be better than the last few for some surprises and bumps on the way, allowing snow to fall. A neutral NAO is probably favoured during these spells of ENSO and solar activity combined. However there are other factors that need to be analysed through autumn to secure a solid winter 2017/18 UK weather forecast. Come back then to learn more on Winter 2017-2018 in the United Kingdom.
Winter 2017/18 thought: average with potential long lasting cold in January.