Winter forecast 2022/23: The Winter of Discontent?

Winter Forecast Headlines:

• Overall over December, January and February the 3 months of meteorological winter, temperatures are forecast to be colder than average to 1991-2020 long-term average.

• Drier than average winter, however, snowfall above average especially in southern UK. The risk of disruptive snowfall is higher this winter than perhaps we seen since 2012/13 winter, and potential the most significant cold patterns since 2018: Beast from the East.

• Above average frequency of northerly and easterly winds: potential for severe cold coming from near continent. The mid-winter period could be particularly challenging. This will also put the grid under significant strain. An emergency footing might be necessary this winter given the already present difficulties securing energy, with French electricity imports weakened. As many nuclear plants are under maintenance. A cold and low wind scenario is the worst scenario and I have concern for this winter.

Continue reading for a more detailed breakdown and explanation of the factors involved which were used to construct this rather eyebrow-raising winter forecast. I will immediately add the caveat I am not a professional meteorologist, just a very big weather enthusiast who has built up his knowledge over years on the Internet. Therefore, forecasts from people like myself should be taken extra cautiously as I can afford to be bolder, I do not have clients like professional organisations such as Met Office.

ENSO (El Nino Southern Oscillation) and recent winters

This upcoming winter will be the third consecutive winter with La Nina conditions. Such long-duration events are extremely unusual; since 1950 there have only been two other incidences, the first in 1973-1975 and the most recent 1998-2001.

This gives context to the unusualness of complex global weather patterns resulting from variations in ocean temperature in equatorial Pacific. La Nina is identified by a colder equatorial Pacific. Historically more colder winters have been seen during La Nina (cold ENSO), and there does seem to be a greater tendency for cold spells earlier in winter with more blocked patterns. Than warm equivalent, El Nino, indeed 2016 was Earth's hottest year on record in midst of a strong warm ENSO event. Weaker Nina events have the most striking correlation with colder winters in northwest Europe including UK.

If we remind ourselves winter 2020/21 was a quite seasonal winter the January was coldest January since 2010, and early February brought a spell of very cold easterly winds even in London daytime temps were subzero, but, away from coasts of East Anglia and Kent snowfall was not widespread or significant. It was a winter where the wind direction aligned to deliver cold to very cold weather, however, what was noteworthy during this winter was lack of deep cold air. Particular frustration for example was from rainy January easterly. This led to many blaming climate warming on lack of deliverance it was a likely handicap.

Winter 2021/22 on the other hand had very little in way of cold weather, indeed for many late November brought only wintry weather that winter. The winter was milder than average, despite other promising background signals this was entirely drowned out by a very strong stratospheric polar vortex. This is a spiny low-pressure intense area of upper westerlies which typically sits in the Arctic, normally a strong stratospheric vortex has a strong influence on the troposphere lower area of the atmosphere, where weather happens, for example, reinvigorating the jet stream. This often results in stormy and mild weather in NW Europe the last winter suffered greatly from an enormously strong polar vortex much stronger than normal. It is really quite unlikely we see a repeat of that this winter.

Moving back to state of ENSO this winter La Nina conditions are expected to persist throughout the winter but then transition to neutral-ENSO in spring 2023.

The cold SST (sea surface temperature) anomalies are greatest in the east of basin. There are different types of La Nina events, sometimes it is basin-wide Central Pacific (CP) La Nina where cold ocean temperatures are equally distributed. In this upcoming winter, we are seeing an Eastern Pacific (EP) La Nina. This can give different responses to the tropical atmosphere, what happens in the tropics, does not stay in tropics! Studies have shown EP La Nina are most favourable to cold winters in Europe compared to CP La Nina.

My takeaway from ENSO this winter and the type of La Nina is that it is really quite favourable for cold weather patterns in Europe.

Historically it has served us well, a Nina which is declining in strength through the winter and is east based is an interesting trajectory. Which could mean unlike in the 2010 winter, which featured a strong La Nina event after experiencing coldest December since 1890 the winter really burnt out. Cold and blocked weather patterns are perhaps more likely to sustain in a weakening La Nina winter. Therefore, cold weather patterns which are expected this December are more likely to continue into January and beyond.

Sea surface temperatures (SST)

Sea temps surrounding NW Europe and UK to north and east are noticeably warmer than average, by as much as 2C in the southern North Sea beside SE England. Immediately this is not a positive factor as east and north winds are likely to be more moderated and hence brings a higher risk of temperatures insufficient for snowfall. However, if a very cold polar continental air mass was to travel over these relatively warm seas, the snowfall rates could be quite something to behold in eastern England and Scotland.

Looking at the wider North Atlantic there is quite a dipole frequent cold westerly winds from Canada has resulted in significant cooling in mid Atlantic a significant change from a month ago when the map was entirely red. Therefore, westerly winds potentially quite a cool direction which is a change from earlier thinking.

Northern Hemisphere snow cover

Snow extent in the Northern Hemisphere at end of November is very high at about 41 million square kilometres according to NOAA the highest in decades. Russia is entirely blanketed, snow is also covering nearly all of Alaska and Canada. Snow cover increases albedo of which freshly fallen snow can reflect 90% of incoming solar radiation back to space. This allows more heat to be lost, and thus it is colder than absent snow cover. Of course in last decade, we have all seen high snow extent also despite that winters have been mild in NW Europe. While there is no explicit signal to colder winters. In the event the weather patterns do align, for example, winds from Siberia a thick and widespread snow pack is likely to contribute to a colder easterly flow so it is undoubtedly positive to see for cold weather.

NAO (North Atlantic Oscillation)

If you have been watching my tweets lately you might have noticed how I keep yapping on about North Atlantic Oscillation. The NAO is a measure of the atmospheric pressure gradient between the Icelandic Low and the Azores high. The strength of NAO determines the strength of westerlies. A positive NAO is indicative of a stronger than average pressure difference between these two regions. As a result, this thermal gradient north and south creates a strong jet stream and greatly increases risk of milder winters in Europe. However, when in negative phase there is a weaker than average difference between Icelandic Low and Azores High. Consequently, colder winds from north and east are much more frequent as the North Atlantic is effectively blocked off with high pressure to north and west of UK.

An explanatory video on what is the NAO? Courtesy of UK Met Office

Predictability of winter NAO is limited typically only to 2 weeks out, but when NAO is particularly strong or negative often this can last for a prolonged time and really determine how the winter evolves... from an early juncture. Once in a strongly positive NAO phase a time of enhanced westerlies, it is very hard to break out from. Which is why I have been recently emphasising the significance of current forecasts and how rare they are in early winter. A significant -NAO is in forecast in early December this is very unusual indeed.

As previously stated the NAO in negative phase equates to weaker westerlies visiting the UK and northwest Europe and therefore the risk of cold spells is much higher. The more unsettled weather goes to the Mediterranean as the storm track is deflected to our south by high pressure areas in North Atlantic. What is interesting about previous Decembers which featured major blocking which this upcoming December is expected to have.

The majority of January days (62%) also featured -NAO giving a sense of long term control on upper air patterns. Thanks to Ben Noll.

December 2010 was an example of a very cold December with a very powerful -NAO the coldest December since 1890 in UK, but the rest of winter was unremarkable. In contrast to that winter I believe the mid-later winter period will harbour a less destructive environment in the breakdown of -NAO. We do not have a strong La Nina like in 2010 which increases risk of mobile, unsettled weather especially later in winter, indeed by the end of winter the forecasts show Nina conditions as looking weak. Which I have alluded in that it has highest correlation with colder winters in UK. My idea the strong -NAO in early December will serve a template for the rest of the winter, with greater confidence of colder and blocked patterns extending into January. Potentially this could all lead up to January seeing exceptional cold from north or east as the cold accumulates in the Northern Hemisphere at the coldest time of year. Much less confident on February but a blocked Arctic profile is likely to result in a much weaker than average stratospheric polar vortex. As such the chance of SSW (sudden stratospheric warming) is higher given that December is typically a time of rapid intensification.

Final thoughts on upcoming winter

• A colder than average winter is favoured by me, potentially much colder than 1991-2020 normal, rainfall below average or near normal.

• December is expected to be cold, likely coldest since 2010 - confidence is quite high. An increasing risk of snow near mid month onwards a white Xmas could be worth a flutter this year. It is possible the pattern could briefly relax and turn less cold before turning cold or very cold again late in the month.

• January the coldest month of winter or featuring the coldest weather of winter, with highest risk of severe cold in UK/Europe. The cold could be quite extensive in mid lats of Northern Hemisphere something we have not seen in a number of years.

• February significant uncertainty, it could be much milder a taste of spring or the cold could persist, a breakdown is likely to occur the transition period could bring snowfall.

So there is my winter forecast for 2022/23, I have not done a forecast like this before. It is worth noting cold and snowy winters are not normal in UK, and never have been really. The average number of cold winters is 1-2 per decade, the maritime climate of northwest Europe makes it very difficult on top of European warming trends.

There is potential this forecast could go spectacularly wrong. I'm sure many will be hoping I am wrong with cost of living backdrop; coming when it is least needed. In some way I am trusting the early December deep polar blocking to leave a scar and imprint on upper air patterns, there is a risk it could collapse swiftly but I am prepared to be brave. As I do not think the risk is insignificant, I think it is worth communicating.

What is noticeable already in Northern Hemisphere is a greater availability of intense cold air, and snow cover is well above average. The Siberian High is also very strong, a cold air factory. The macro situation seems quite dissimilar to what we have seen in last decade which has seen aggressive winter warming in Eurasia, with emergence of a powerful -NAO very soon. In my opinion it is most primed for a cold winter affecting UK since 2010 winter.

Thanks for reading.

Dan

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Summer Forecast 2022 UK & Europe

Summer Forecast 2022 headlines:

• Overall, a warmer than average summer is favoured possibly average to recent 1991-2020 baseline.

• A wetter than average summer is quite likely for UK and wider NW Europe with entrenched strong La Nina conditions, with rainfall fairly evenly distributed.

• The driest month of summer and expected to feature hottest weather will likely be in July however August could well surprise.

• V high temperatures are still possible >35C, in the past with this background this would have been rather unlikely but with warming of European climate we can't be certain.

A justification and explanation for the above outline of summer 2022 will be given in subsequent paragraphs in terms of the factors at the play including: El Niño–Southern Oscillation (ENSO) and North Atlantic Sea Surface Temperatures (SSTs).

Seasonal Forecast Models

We are fortunate there is an extensive selection of seasonal models available over JJA (June, July, August). It is worth emphasising that these are three month smoothed averages therefore a cooler month against two warmer months would be totally muted out.

As can be seen from below selection of best NWP the picture is a sea of warmth excluding some northern areas of Scandinavia, where a near normal summer is favoured.

European model which exhibits some of the largest skill is among warmest with large area of continental Europe and S/SE England 1-2C above average, this might not sound like much but for an average over three months it is a very striking signal for a very warm summer. There is quite significant overlap with French model which is interesting indeed. The UK Met Office are also anticipating a warmer summer but nothing unusual which is my thinking as well.

El Niño–Southern Oscillation (ENSO)

A La Nina summer is highly favoured throughout summer 2022, this requires sea surface temperatures in 3.4 area of equatorial Pacific at least 0.5C below average, last time this was achieved was in summer 2011 which was extremely unsettled. This phase of El Niño–Southern Oscillation (ENSO), the cold sea phase has a direct cooling influence on tropical weather patterns. It also has influence on weather patterns at higher latitudes think of a slinky being stretched the reverberations travel wide changes to direction of jet stream ect.

Some debate how much influence ENSO has on UK summer but I am a believer it has a significant role, and it is one of the main reasons I consider an unsettled summer likely, it is over a decade since we have seen similar ENSO. The really poor summer period 2007-2012 was characterised by this destructive, strongly coupled, ocean-atmosphere La Nina background state. Typically with La Nina summers usually later in summer is more affected with an early onset of autumn this was indeed the case last summer where it emerged. September now seems to often play by its own rule book nowadays.

Atlantic Sea Surface Temperatures

Summer 2022 will be the third consecutive year with La Nina present the last "triple dip La Nina" was in 1998-2001 and there were only 2 other occasions in the 20th century demonstrating how rare these entrenched La Nina conditions are. We see that SST anomalies over North Pacific and North Atlantic early in summer are really quite similar to these years as well as 2011, which as previously stated was last summer strongly Nina throughout. The warm waters around UK and Ireland and indeed notably in the Mediterranean Sea are intuitively a good thing for a warm summer, however, warmer water causes the air above ocean to warm and rise which leaves an area of lower pressure. Suggestive of a more conducive environment for downpours and heavy rainfall as a result summer 2022 could be prone.

Current SST anomalies

June

The analogs for this summer (1998-2001 + 2011) show a strongly westerly driven June with most unsettled conditions in Northern UK, does not paint well for a flaming June. A very warm and dry June in the Mediterranean is favoured might be good to look at last minute deals.

July

The best fit year years show a horrific July across Europe been many years since there has been similar. Cool and extremely unsettled particularly centred on Central Europe, let's hope this does not pass as I believe July could see the best weather of the summer. It is likely though it will not be perfect summer month - mixed at times.

August

Strangely on what we are used to seeing August is shown to the best summer month - not for Scandinavia I might add. Low pressure is signalled to southwest of Ireland low pressure in this area is often associated with heat in Western Europe working like a pump. August potentially is one to watch it would be unwise to dismiss it based on what seems to dominate in 2000s.

Recap Summer Forecast 2022 headlines:

• Overall, a warmer than average summer is favoured possibly average to recent 1991-2020 baseline.

• Good chance one summer month has below average temperatures.

• A wetter than average summer is quite likely in NW Europe with entrenched strong La Nina conditions possibly a harsh and dry summer in the Mediterranean.

• July most likely to feature hottest weather of summer but August could be a dark horse typically with La Nina summers August likes to go pear-shaped could be untraditional.

• V high temperatures are still possible >35C, in the past with this background this would have been rather unlikely but with warming of European climate we can't be certain.

There you go that is my summer forecast for 2022 I hope it made for a good reading. Please share with your family and friends. Donations to keep the site running are also highly appreciated but not expected.

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Winter 2021/22: All or Nothing

Well here we go again, winter 2021/22 is here, and many of you are eager to know how this winter may shape up to be.

The forecast headlines are:

Overall, temperatures are forecast to be colder than average expecting the coldest winter in UK since 2012/13

January expected to be the coldest month, however, coldest weather could happen later in winter, after mid month, possibly SSW induced and extend into February, potential for notably low temperatures with significant wintry hazards

50-60% likely to be a wetter than average Winter drier in the east

December forecast to be the wettest month

First, I will examine the main global climate drivers of winter 2021/22 of which when are in different amplitudes/phases can give a broad idea of how winter will turn out.

ENSO (El Nino Southern Oscillation)

This autumn we have seen La Nina conditions redevelop this is associated with cooler than normal sea surface temperatures (SSTs) in central and eastern Pacific. Nina conditions are expected to last through entirety of winter 2021/22. This is second winter in row with La Nina conditions we saw the ENSO go neutral in spring and this lasted through summer.

During La Nina, the easterly trade winds are stronger this means significant upwelling of deeper and cooler subsurface waters, to ocean surface, therefore, we see central and eastern tropical Pacific Ocean become colder than normal.

What we see is the strength of La Nina/El Nino affects the position and strength of jet stream the atmospheric changes in North Pacific in turn influences the weather in North America, and the altered jet stream continues onwards across North Atlantic and Europe in like a connected chain. A ripple thousands of miles away in North Pacific can have a large impact on the type of weather we see. During La Nina we often see an Aleutian ridge a big area of high pressure off western North America in North Pacific, this often causes North Pacific jet stream to bend sharply S/SE across North America. Often La Nina winters are colder and snowier in Canada.

The wavy jet continues as it exits east coast of US across North Atlantic and to Europe, and notably this meridional theme is more frequent with weak La Nina conditions, and coldest anomalies are in eastern Pacific we often see Atlantic ridging a blocking area of high pressure to west of British Isles. The mobile westerlies are gone and this encourages colder northerly or easterly winds. Interestingly we begin December 2021 with weak La Nina conditions and also the coldest anomalies are increasingly focused more in east. This means chance of cold snaps in early winter are rather high in Europe.

A strong La Nina favours a strong jet stream this is associated with +NAO (North Atlantic Oscillation), winters which are dominated by this are often very mild and unsettled winters. Indeed in last decade we have seen many of them. It is advisable to never take a broad brush approach with forecasting every winter is unique, indeed in 2010/11 winter which UK experienced its coldest December since 1890 the La Nina was strong although coldest anomalies were in eastern Pacific, which could have been crucial.

The 2010/11 winter although burnt out very quickly, which likely was due to strong nature of La Nina, but again highlights regardless of strength of La Nina we tend to see increased chance of cold weather patterns earlier in winter. This winter we could see further strengthening but likely no more than moderate. As such the second half of winter could have a higher chance of cold spells than the traditional La Nina which coldest anomalies are fairly evenly distributed west to east, and the further we head into winter the unsettled westerlies gather in strength.

In summary I find ENSO encouraging and to be highly influential this winter but uncertainty lays is how much strengthening of La Nina we see over winter, La Nina becoming strong while unlikely would increase probability of a mild and wet late winter.

The Quasi Biennial Oscillation (QBO)

This sounds complicated doesn't it? Essentially in a very simple way it refers to winds blowing above equator every 14 months or so, these winds can completely change direction from westerly to easterly or vice versa. This winter we will be in easterly phase of QBO and again the last time it was during 2017/18 winter. Notice the links which are being made with that winter? Which was also a La Nina winter. During easterly phase of QBO we tend to see increased risk of disruption to polar vortex, which slows down jet stream increasing risk of cold weather outbreaks. We are not only seeing easterly but a strong one, while sample size is not huge since 1950s we have never had a winter which was mild with deeply descended easterlies. Thanks Marco! Overall, this year QBO is particularly favourable to a cold winter and to a higher chance of polar vortex disruption, and I anticipate will be highly influential.

Stratosphere

Now onto the stratospheric polar vortex (SPV) which also feeds into previously discussed QBO, very important in determining winter prospects, this is is a huge area of very cold, low pressure which forms in autumn with return of polar night, it spins anticlockwise at North Pole in December-January it reaches peak strength.

The stratospheric circulation is higher in atmosphere above the troposphere, the troposphere is where the weather happens, what we see with stronger stratosphere polar vortex (SPV) is like paint dripping down a wall the enhanced westerlies high in atmosphere propagate down into troposphere and we see a strong tropospheric polar vortex (TPV). This, therefore, accelerates the speed of the jet stream a strong jet stream is likely to bring lots of low pressure, wet and windy weather at our latitude.

So knowing the state of polar vortex is very useful tool unfortunately predictability is rather low beyond week 2, hence, occasionally seasonal models can go epically wrong, disruption to these upper westerlies can totally radically change weather patterns across Northern Hemisphere to be more conducive to wintery outbreaks. This was exhibited in February 2021 and perhaps more famously in February 2018 which were a result of Sudden Stratospheric Warning (SSW) and featured a split - these serve like a sharp pin popping a balloon, significant cold is unleashed from higher latitudes but not everywhere can see this extreme cold.

This winter we begin with a stronger than average SPV, this is not positive for cold weather patterns in mid latitudes, if this is to continue a wetter and milder winter would be favoured with a ++ Arctic Oscillation (AO) trapping cold in North Pole, however, what we've seen so far these strong westerlies have failed to really descend and influence our weather patterns. You will have observed how dry November has been.

In recent days we've seen a sign of a disturbance in the force with Dr Cohen well on the case, the signalling of Ural Blocking was also seen last winter this helped result in SSW in January 2021, and weeks later in February we experienced some very cold easterlies albeit not as dramatic as 3 years earlier.

The signalling for this atmospheric "road block" earlier in mid December is interesting, as this could weaken the polar vortex and increase risk of a significant cold spell in January the coldest month of winter. The strong easterly phase of QBO this winter in tandem with La Nina also enhances risk of disruption to polar vortex and cold weather patterns in Europe, therefore, I believe the probability of an "attack" is quite high this winter.

Solar Cycle

This is a one which the science does not agree upon, nonetheless I am an observer and advocate. I noticed the increased northern blocking patterns and wavy jet stream after 2008 solar minimum, and again following late 2019 solar minimum our weather patterns have become more 'unstable' oscillating between v wet and dry. We are no longer in solar minimum but it is believed the ascending part is where we tend to see lag effects, interestingly this December will be 2 years since solar minimum. December 2010 was also 2 years following 2008 solar minimum and activity is very similar, it might be a tenuous link but an interesting one.

Northern Hemisphere snow cover and Arctic ice

Snow coverage across NE Europe is more extensive than this time last year, the Scandinavia region is also significantly colder. Sweden in recent days has witnessed its lowest November temperature since 1980. This thickening snowpack and rapid fall in temperatures means northeasterly winds are likely to be unusually severely cold for so early in winter.

Current Eurasian snow cover

Eurasian snow cover 26th November 2010

The Eurasian snow cover we see it closely resemble late November 2010, also we observe uncanny similarity with Arctic sea ice, in fact as of 28/11/2021 we have over 400,000 square km more ice. This is reflected by a colder Arctic of which I have mused over this autumn. Last winter we greatly struggled with having sufficiently cold air, the patterns were favourable with good air flows but they did not live up to expectations. Winter 2021/22 likely for this to be less problematic, and thus could make a major difference in marginal snow situations.

North Atlantic Sea Surface Temperatures

The North Atlantic at present is warm, however, lately with chilly northwesterly winds this has caused SSTs to drop closer to normal NW of British Isles, meaning Polar Maritime northwesterly winds will not be particularly modified. The subtropical Atlantic is particularly warm this has contributed to some of exceptionally mild conditions this autumn, any southwesterly flows this winter are likely to be very mild across Europe.

In winters 2009/10 and 2010/11 the Atlantic SST anomalies were quite favourable we had a tripole pattern, this is when you have cold waters sandwiched between warmer waters to the north and south. This winter we do not have this, but I theorise the widespread above normal SSTs could be ironically beneficial, temperature gradients fuel the jet stream and associated wet and stormy weather. The North Sea is also comfortably above average this may make easterly winds less cold, however, if we see bitterly cold Siberian winds there would be vigorous convection, frequent heavy snow showers in east/southeast. Overall with SSTs there are good and bad aspects I don't anticipate Atlantic SSTs to be particularly influential.

Seasonal models

In last 15 years particularly we have seen great advancements in long range seasonal modelling most of models UKMO, ECMWF and Meteo-France are going for a milder than average winter +NAO. It is worth noting a three month mean can mask an awful amount of variation for instance one cold winter month against two much milder months the cold anomaly is completely lost, being a country which does not typically experience prolonged cold/snow they must be used carefully.

UKMO's Glosea depicts a mild winter with dreaded Euro high, the jet stream is kept to north of UK allowing for a dry winter with an unusual lack of winter storms.

French seasonal model is likewise going for an above average winter, but increased mobility of Atlantic westerlies a wet winter in this case, which also might lessen the mild feel.

The European model by far most compelling for a cold winter signal, average temperatures are favoured overall, there is also evidence of a high latitude blocking signal Scandinavia is shown warmer than average which possibly suggests an anticyclone. This encourages cold easterly flows into Europe. What is more stark is strength of the warmer signal between Iceland and Svalbard, I believe this suggests a strong northern blocking signal, blocking here historically has resulted in some rather extreme and protracted cold winter conditions.

Typically I give a monthly breakdown but I do not think this is sensible, no one on this planet could give you a 100% roadmap of how this winter will evolve particularly this one.

In summary, as earlier mentioned the headlines are;

• Overall, temperatures are forecast to be colder than average expecting the coldest winter in UK since 2012/13

• January expected to be the coldest month, however, coldest weather could happen later in winter, after mid month, possibly SSW induced and extend into February, potential for notably low temperatures with significant wintry hazards

• 50-60% likely to be a wetter than average Winter drier in the east

• December forecast to be the wettest month

This is the first winter forecast I have gone for a colder than average winter, I am not super bullish it will be cold, so I am taking a calculated risk the benefits I suppose of not having clients, but this winter will likely go one of two ways. Despair or jubilation. Very wet and Atlantic driven or the blocking wins out and cold if very cold weather dominates. I hope that wasn't too wordy, I look forward to sharing more with you @TheSnowDreamer

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