iapennell

http://www.weathercharts.org/wetterzentrale-t120-t384.htm#228 And this too, also for 20th April: These charts are for nine days' hence (20th April)- it does not look particularly settled anywhere. This sort of weather-pattern could bring quite cold weather as well. I see no reason to alter my predictions based, not only on the long-term of these weather-charts- but on other such large-scale fundamentals as a record Westerly QBO and the pattern of sea-surface temperatures across the North Atlantic. For sure, when the upper Westerlies that encircle the Arctic weaken in spring they become subject to short-term weather conditions at the surface and that makes them a little unpredictable but my money remains on late April through much of May being unsettled and wet, particularly in the North and Scotland.

The possible implications of heavier snowfall over Greenland (as this winter past) and more melting in summer, combined with heavier rainfall and snowfall over the far North Atlantic (as storm-tracks move northwards with the shrinking seasonal Arctic ice-cover) could freshen the North Atlantic Ocean to such an extent that the Thermohaline Circulation, otherwise known as the North Atlantic Drift, could shut down before the end of the 21st Century. This possibility is spelt out in the following article: https://article.wn.com/view/2017/02/01/Is_the_North_Atlantic_headed_for_an_ice_age/ If the North Atlantic Drift weakens drastically or shuts down completely before this century is out the impact on the climate of Britain, much of north-west Europe and the eastern US will not be one of warming but quite a sharp cooling that would more than counteract the CO2-induced warming by the end of the Century. heavier snowfall with more melting that more than removes accumulated winter snow-cover over the entire Greenland Ice-cap has some serious implications. It could indeed be what is responsible for the record calving of ice-bergs in the NW Atlantic (see reference above) and the presence of the so-called "North Atlantic Cold Blob", a large patch of substantially colder-than-normal water in the North Atlantic which is about the size of western Europe: See article about it here: http://blogs.reading.ac.uk/weather-and-climate-at-reading/2017/an-update-on-the-north-atlantic-cold-blob-january-2017/

@BornFromTheVoid, Whatever you think about the Ice Age Now site references to the Greenland Icecap's record snowfall accumulations over the autumn and winter just gone come from several sources: http://polarportal.dk/nyheder/nbsp/nyheder/heavy-snowfall-in-greenland/ and here: https://realclimatescience.com/2017/01/greenland-blowing-away-all-records-for-ice-growth-3/ and these here: https://www.longroom.com/discussion/264182/greenland-enters-2017-adding-extraordinary-amounts-of-ice-and-snow https://steemit.com/globull-wurming/@everittdmickey/greenland-ice-sheet-growing Whilst I do not deny that Greenland has been losing mass due to global warming over recent years, you have here information from a number of sources that suggest that there has been excessively high snowfall totals this last autumn and winter over the Greenland Icecap (because of record warmth in the Greenland Sea just to the east and the northwards passage of far North Atlantic depression-tracks). The amount of snow- over 20 cm above normal in terms of water equivalent for the season over a wide area- will require sustained warmth and melting *along with glacier calving into the surrounding seas) to get the Greenland Icecap back to the state it was in at the end of August last year. However, some of these reports emphasise that for north-west Greenland only, snowfall amounts were below normal last winter but not by much, hence it is likely that these areas of the ice-sheet will see a net loss of snow and ice (but not by much, because the NW of Greenland remains cold during most summers being so far north). This does not detract from the fact that, over east and SE Greenland but also into the interior where little melting happens, snowfall over the last six months has been well above the long-term normal and this will have implications for the local mass-balance of the ice-sheet.

https://www.iceagenow.info/greenland-ice-sheet-growing-record-rate/ Possibly as a result of above-normal temperatures of surrounding ocean surfaces (and less sea-ice around this winter gone)- leading to more moisture in the atmosphere over Greenland; the Greenland Icecap has had record snowfall amounts over this last autumn and winter (2016/17) with almost double the normal amounts of winter snowfall on the Ice-cap. If that is so, it will have to be record warm summer on the Icecap to give rise to continued net loss. Much depends on whether open and warmer-than-usual waters in the Greenland Sea- from where some of Greenland's most prevalent winds come results in a repeat scenario for the next few winters. If then, in summer, lower pressure occurs over the Arctic and adjacent areas leads to more cloud-cover and substantial summer snowfall on the higher parts of the Ice-cap (possibly due to less Arctic ice leading to sub-polar depressions regularly penetrating deep into the Arctic or the record Westerly QBO this year repeating in later years- leading to lower pressure in high latitudes) then the net annual accumulation of the snow and ice may well turn positive with more winter snowfall than melting in spite of higher annual mean temperatures on the Icecap.

You are probably right there, throughout the winter promising cold-weather synopsis a fortnight or even ten days out has tended to be watered down as the time for it to occur drew near. I expect this mid-April one to occur however, as a good number of the weather models predict it and the stratospheric wind/pressure pattern over the Arctic and sub-arctic is predicted to weaken and then become easterly in the next ten days- this is (again) consistently indicated. A weakening of the high-latitude Stratospheric Westerlies and their then becoming easterly if, of course normal during April as the high Arctic high Stratosphere warms up under the 24-hour sunlight that commences this month; however a sizeable patch of colder stratosphere is predicted to cover Russia with a strong warmer "high" over northern Canada and Greenland by mid-month. This is quite consistently predicted and it is certainly conceivable that an influence of this upper-air pattern will affect the troposphere below- leading to anomalously north or (at least) north-west winds over Britain. However, the strength of the Westerlies high up above the Equator (it has already been like this for several months) and the temperature-patterns across the North Atlantic may yet lead to a more Atlantic influence getting into the mix, hence the Arctic spell (when it occurs) may well be north-westerlies with one or two wet and less-cold westerly interruptions. All the same, this still leaves plenty of scope for snow-showers across the North and for night frosts to occur as far south as Bristol and Guildford.

Yes, there was a spell of Arctic winds in mid-April last year that brought four inches of snow to the North Pennines followed by temperatures at night falling to -3C as skies cleared. Then winds often remained from a northerly quarter for the remainder of the month bringing further wintry showers and frost at night. Fortunately that was saved by a warm dry May that made up for lost time. Late April this year is likely to be chilly and wet across the North and Scotland- with snow in the mountains-and (in northern regions at least) it is not going to be compensated for by a warm dry May. As to how the summer this year will turn out, I would not want to make predictions at this stage. However the current temperature-anomaly pattern across the North Atlantic and the zone of anomalous strong Westerlies high up over the Equator are two factors that I would not want to still be in place in six weeks' time for a warm dry summer across Britain. However, as I have pointed out, the seasonal weakening of the upper Westerlies during late-spring and into summer (though I am confident it will be stronger than usual for the time of year on the whole) means that regional weather-patterns are at the mercy of alteration as a result of a single storm, a few days' unusual heat over Canada or a late snowfall over Sweden. Some volcano in the Philippines could blow it's top- putting dust in the atmosphere that helps warm the upper-air and cool the surface next month, that would greatly alter the pressure and wind-patterns and render invalid any prediction made currently. We could have some very hot weather during the summer- especially in view of the above-average sea-surface temperatures around our shores- but it really is too early (and too far from the summer season) to make any concrete predictions as yet.

@karyo, The QBO typically works it's way downwards through the Equatorial Mesosphere and Stratosphere with time- look above the 30 and 50 mb level (where there are these record-strong Westerlies) to the 10 mb level and above what do you see? There is a zone of quite strong Easterlies blowing at the equivalent of gale-force or stronger at this level and it extends from 30S to 20N. This should slowly work it's way downwards through the Equatorial Stratosphere over the next six months, by which time we would expect easterlies at both the 30 and 50 mb levels. That is, of course, assuming there is not some disturbance to knock the QBO off-course (as happened last year)!

There's quite likely to be snow on the Scottish mountains at times during April and early May. Snow-showers are also likely to occur more widely in Scotland and northern England around the middle of April due to an anticipated spell of Arctic winds!

April-May 2017 Prediction:continued.... Firstly April: For this there are the weather charts that give assistance, at least to mid-month. It looks like much of England will benefit from high-pressure systems moving up from the Azores and crossing into Europe early in the month. This will mean that there is a good deal of warm dry weather with temperatures reaching 20C in the most favoured parts of the South East and South Midlands at times, clear periods at night will mean localised frost with minima in most locations likely to fall to or below 5C in most places. Further north, passing fronts associated with North Atlantic depressions will bring rain at times and a fresh south-westerly wind. Any snowfalls are likely to be restricted to the Scottish mountains above about 800 metres, owing to the prevailing south-westerly winds. However, even here high-pressure will nose in from further south at times leading to some warm spring sunshine and maxima reaching 15C oven in places like Aberdeen and Dundee. A fine, but cooler spell is likely around 10th April as high-pressure affects the whole country with light north-easterly winds- night ground-frost is likely to become widespread with air frost probable in Scotland and northern England. Mid-April looks like bringing a week of colder weather with high-pressure west and north-west of the country and depressions crossing Scandinavia; this will bring colder north or north-westerly winds and this means snow-showers in Scotland and upland parts of northern England. Daytime maxima will be below 10C except in the South and there will be widespread air-frost at night. In parts of Scotland and northern England valleys expect minima of -2C or below during this period. During late April there are indications that high-pressure over Greenland will hang on, but weaken with high-pressure often south-west of the UK. However, the emphasis will be on increasingly unsettled conditions coming in off the North Atlantic associated with depressions that will brush by north-west Scotland. The sea-surface temperature patterns and the QBO indications lend themselves to this being the more likely outcome. Spells of cold wet weather borne on westerly winds (with snow above 600 metres) will affect Scotland- farmers with lambs beware! These conditions will also affect northern England and Wales at times with snow on the highest ground on occasion and there will be the odd westerly gale affecting the North West and western Scotland. The South of England and South Midlands will escape most of the chill wet weather and here there will be a good deal of sunshine and warmth at times- some fronts from further north will bring rain at times. The only consolation is that night frost will become much more infrequent, even in Scotland, owing to frequent cloud-cover and the prevailing wind-direction being westerly rather than northerly. April 2017: CET of 9.5C; England and Wales rainfall average total of 90 mm. Scotland: Average lowland temperature: 7.0C, Average total rainfall of 120 mm. For May 2017 the general prognosis is not good except in the Midlands and South where there will be a good deal of warm dry weather at times. Starting with the English Midlands, Yorkshire and southern England there will be a good deal of warm dry weather with high-pressure crossing southern and central Europe extending its influence northwards, Prevailing winds will be west or south-westerly so despite clear nights ground-frost will be unlikely except in the most sheltered frost-hollows and the strong May sunshine will regularly raise air-temperatures to 22C or above over a wide area. There is even the likelihood of a hot spell during the second half of the month with winds turning southerly and bringing air up from the Mediterranean for a few days- temperatures across the Midlands and South will widely reach or exceed 26C. However, with the assistance of upper troughs to the west, this hot spell is likely to degenerate to widespread thunderstorms with localised heavy rain and even hail- combined with a sharp drop in temperature to more seasonable levels as the wind veers towards the west. That said, even in the south there will not be fine weather throughout May as frontal influences push in at times and early May is likely to be distinctly cool and breezy with regular showers. This will be an effect from high-pressure extending north into the mid-North Atlantic and the still-present Greenland High (Greenland itself will be slower to warm up this spring than it might otherwise, record winter snowfalls over the ice-sheet have increased the surface albedo to 85 to 90%). Depressions are more likely to pass closer to the north of Scotland and bring chillier air in its wake at times- with frontal influences pushing further south- as a result. Frost at night will still be unlikely in the South early in May due to breezy conditions, patchy cloud-cover and moist ground though ground-frost may affect frost hollows on the few clear nights following cooler westerlies. For North West and North East England (excluding Yorkshire), Wales and Scotland conditions will not be so amenable: Early May is likely to be chilly and particularly wet (with snow in the Scottish mountains at times). A good number of days will struggle to reach 10C, even in the lowlands. However, even here there will be some bright and warmer days in between the passage of depressions to the north of Scotland, although clear nights following westerlies will be colder and local frost cannot be ruled out. Wales, however, is likely to be warmer and most places will escape frost worries, although it is still likely to be wet. Westerly gales are likely to affect the far northern coasts of Scotland along with the Hebrides at times early in May. Later in May the weather will become considerably warmer over the north and west of the country as low-pressure remains more to the north-west of Britain whilst pressure rises in the south: This will result in winds coming in more from the west and south-west and there will be a little less rain as depressions to the north-west become a little weaker heading towards summer. There will, consequently be a good deal of warm, bright days with temperatures reaching 20C in places like Preston and Newcastle on occasion and these conditions will occur between frontal passages. The fronts crossing the more northerly parts of the country in late May will bring heavy showery rain at times, and locally accompanied by hail and thunder. The warmer airstream and shorter nights is likely to put paid to any risk of frost in the North and Scotland during the second half of May. A spell of very warm southerly winds that is likely to happen late in May will bring hot weather to the South of England and also bring a day or two of heat to South Wales (with maxima locally at 25C), but the warm southerlies and the daytime heat and sun associated with it is unlikely to get north of a line from Liverpool to Middlesbrough, this period will be associated with humid south-westerlies with plenty of cloud and patchy rain further north. It is unlikely that anywhere in Cumbria, Northumberland or Scotland will exceed 22C during May owing to the generally unsettled conditions. For May 2017: CET of 13.0C, England and Wales Rainfall (average total) = 80 mm; Scotland average temperature (lowlands): 10.5C; Rainfall (average total)= 110 mm

First of all, apologies for not getting the complete Spring 2017 forecast out in time. I was on holiday in Churchill (Canada) with my brother in late February, then when I got back I had exams to study for. I was also beset with sickness for much of March so little time to get onto the Netweather Forum let alone make seasonal forecasts! I will rectify my shortcomings by producing a forecast for the next two months, but I will not be tempting providence by producing a Summer 2017 prediction before the middle of May. In the summer half-year the Circumpolar Vortex is weak and regional variations in sea-surface temperatures provide the better hope of making a prediction for the season. Even that can get blown off course by a deep depression pushing into Scandinavia or a "Spanish Plume" that drastically alters local temperature and pressure patterns which can flip the upper-level Rossby waves into a completely different configuration that could prove to invalidate earlier predictions of the season. With these provisos in mind I will provide details of the weather that we can expect in April and May this year: A number of important controls still look like they will shape the weather we get in the UK over the next couple of months. Firstly, sea-surface temperatures are some 2 to 3C warmer than usual around the United Kingdom but the North Atlantic south-west of Iceland is some 2C colder than usual and waters off Newfoundland are up to 3C colder than usual. Much of the north Pacific is also chillier than normal for the start of April but further north the Arctic waters are warmer than usual and the same is true of sea-surface temperatures in the Barents Sea (north of Norway) where sea-surface temperatures are 3 to 4C warmer than usual. Arctic sea-ice, as you may be aware, has started to recede from it's lowest maximum extent on record- particularly in the European Arctic sector and in the Bering Sea. Sea-ice extent, however, is close to normal early April extent off eastern Canada and in the Davis Strait between northern Canada and Greenland. This means that the Circumpolar Vortex would, other things being equal, travel a little closer to the Arctic than normal whilst an upper trough will form (more often than not) a little downwind (i.e. to the east) of the anomalously cold surface waters in the mid North Atlantic with the upper flow re-curving northwards as it reaches north-west Europe. This suggests high pressure over Europe but with deeper depressions than normal moving north-eastwards between Scotland and Iceland. This would suggest a warmer than normal April and May but with frequent spells of wet cooler conditions for Scotland, Northern Ireland and North West England. However, there remain global macro-scale controls that could mean the emphasis is going to be more on wet and breezy rather than warm: The Quasi Biennial Oscillation (QBO) is a wind-pattern high up in the Equatorial Stratosphere over 15 miles above sea-level and it has been blowing at record-breaking speeds from the west (at 34 mph on average at the 30 mb level and over 20 mph at the 50 mb level) and this has ramifications for the weather-patterns in higher latitudes. The excess west-to-east momentum of this vast river of air eventually descends and it enters the global tropospheric circulation within a couple of months- within a further few weeks this excess westerly atmospheric angular momentum (AAM) finds its way into mid-latitudes (of both the Southern and Northern Hemispheres). It is the excess westerly AAM transferred into the Northern Hemisphere that we are interested in and unless of course it encounters the Himalayas and Rockies first this will eventually feed into stronger (and more extensive) westerly winds at higher latitudes. The Himalayas and the Rocky Mountains will intercept some of this excess westerly atmospheric angular momentum but by no means a substantial portion of it (let alone all of it) because during the spring lower latitude continents and oceans warm up along with the Eurasian and North American landmasses: Hence strong upper westerlies associated with the subtropical and polar-front jet-streams are pushed to slightly higher elevations in the subtropics and to higher latitudes over mid-latitudes- less of the westerly AAM is stopped by mountain ranges before reaching higher northern latitudes as a result. This can only mean one thing- stronger westerly winds associated with deeper depressions bringing more rain!! Upper-air forecasts hint at a weakening (even a reversal) of westerlies at 60N over the Stratosphere going through to mid April and there are hints that this could result in a cold snap with northerly winds mid-month as high-pressure builds over Greenland. However, it must be remembered that in summer the stratospheric winds over the Arctic and sub-arctic are usually easterly- but clearly Britain still gets wet and unsettled weather then! A strongly westerly QBO does not portend lots of dry fine spring weather in higher northern latitudes and though the hope must be that with sea-surface temperatures around Britain warmer than usual the excessive storms are guided north of the country: However, the large patch of icy water in the mid-north Atlantic will encourage the jet-stream to swing south over and east of there. That means there are likely to be depressions heading towards Britain- and given the effects of the record westerly QBO these depressions will be stronger than normal for the season. Furthermore the south-westerlies associated with these depressions will blow on their southern flank over warmer-than-usual waters just north-west of Britain and they will pick up moisture. I would be inclined, on the strength of these factors alone, to assert that north-west Scotland will have a rather changeable May at best and there will be plenty of rain. Another important factor are developments in the equatorial Pacific Ocean: Sea-surface temperatures for the time of year are 1 to 2C above normal off the coast of Ecuador and these positive temperature anomalies push west towards the central Pacific: This suggests ENSO-neutral bordering on El-Nino conditions which, if anything, will tend to strengthen the upper westerlies associated with the sub-tropical jet-stream over the northern Pacific. This, through a dynamical impact on the structure of the upper westerlies over the North Pacific and North America can lead to increased amplitude between the waves and troughs associated with the Circumpolar Vortex. This could result in fine warm weather over Britain if depressions are carried well to the north of the country but, given the temperature-patterns as they are over the North Atlantic is as likely to mean the jet-stream pushes depressions in from the west on a more southerly track- before they turn north up the western side of Scotland. However temperature and pressure patterns across the Equatorial Pacific are only just bordering on El- Nino so it's overall impact on the United Kingdom weather through April and May will remain minimal. The Sun is also an important influence: Currently the Sun is declining in the extent of it's electromagnetic activity, solar flares and sunspots as we get towards the quiet final stages of the current Sunspot Cycle: An active Sun produces solar flares that (through interaction with the Earth's magnetic field) increase the intensity of winter depressions and attendant westerlies in sub-arctic latitudes. A quiet Sun, by implication, should mean weaker depressions and weaker westerlies in higher latitudes. Also of note is that the Solar Constant has dropped from 1366 Wm-2 a few years ago to nearer 1361 Wm-2 today (a fall in solar output of close to 0.4%), it is of course known that the Solar output drops from Sunspot Maximum to Sunspot Minimum but there are indications that the Sun is going unusually quiet even by the standards of past Solar minima. However, this is not the thread to discuss whether changes in the Sun will mean an end to (and reversal of) global warming; though a quiet Sun ought to point towards a drier, cooler spring in Britain the strength of the Westerly QBO Phase and the sea-surface temperature patterns around and well west of Britain are liable (together) to well overcome the effect of a quiet Sun: The season as a whole does not look to be settled for the north and west of the country. (continued below).

Not really, so much better for snow and cold than anything we have had in the North Pennines for over 30 years!



Hello all, I woke up this morning in the small bed and breakfast that I and my brother are staying at just outside Churchill. After a heavy fall of snow overnight the sky was clear and a frigid NE wind was drifting the snow. The thermometer outside registered -15C and there was a good two foot of snow lying on the ground. It was glistening and beautiful in the pink morning light! Wish you were here?! I am so glad I made the decision to go to Churchill for a week and a bit.... Seems like "Same Old, Same Old!" back in northern England.

@Don, I am off to Churchill (Canada) for eleven days from tomorrow to get my hard frost and snow fix. Expecting it to be good!

@North-Easterly Blast; Most of the time, I would say you are right- in some recent years in particular both September and October have been unusually warm- and the following winter has tended to be mild. Certain large-scale patterns such as unusual warmth in the NE Atlantic, reduced Arctic sea-ice extent for the time of year and high sunspot activity combine to ensure both the autumn months and the winter following are warmer than usual. Warmth in September and October, say as a result of southerly winds, will also keep sea-surface temperatures around Britain warm and (because of the large specific heat capacity of large bodies of water) the warmth of surrounding seas is likely then to persist into the winter- helping to keep temperatures mild. A very warm September in the mix (you mention CET's above 16C) will ensure more latent warmth in surrounding seas which should help to keep the coming winter milder. But there are still exceptions; it depends what is causing the warm September. If sea-surface temperatures remain below normal and Arctic sea-ice cover is close to or above the seasonal norm at the same time as warm southerlies bring September warmth this is much less likely to lead to a mild winter because that is more likely to be dictated by the fundamentals of the Circumpolar Vortex (which is affected by sea-surface temperature anomalies out west- cold sea-surface temperatures would likely persist and encourage a more southerly path of the jet-stream and greater exposure of Britain to cold polar air in the winter months). The weather-patterns bringing September warmth is unlikely to persist and (even if that were to happen) the same pattern that brings very warm sunny weather in September or even early October can bring about extensive frost and fog in January (an example would be a south-easterly airstream associated with a European high-pressure zone). Continental Europe under clear skies and high-pressure is usually warm in September but in December and January the same high-pressure would result in hard frosts and freezing fog over the continent- and which are wafted in the direction of Britain by south-easterly winds blowing around such a high-pressure area. Excessive warmth in early autumn is certainly one indicator of the winter to follow, but I would not rely heavily on it to make predictions as to the coming winter. Late September and October 2011 was unusually warm (temperatures reached record levels on 1st October that year) and although the winter of 2011/12 was a little milder than usual across the country on the whole, much of the country (England and Wales in particular) had an exceptionally cold fortnight from 29th January through 11th February 2012 with temperatures below -10C in places and little birds freezing to death. September and early October 1985 was unusually warm, especially across England and Wales (anomaly about 2C) with a great deal of Indian Summer weather yet late December 1985, January and February 1986 were bitterly cold with hard frosts and snowfalls (February 1986 had a CET of -1C). Sea surface temperatures in autumn 1985 were cooler than normal around the UK after the cold 1984/85 winter (March 1985 was also very cold) and a cool summer that year, Arctic sea-ice extent was high and 1985 was near solar minima- all of which were more profound influences on the ensuing winter.

@North-Easterly Blast, The relationship between September and the ensuing winter does have some correlation - particularly in regard to recent years. September 2016 was summer -like at times and, of course, the winter we have just had was mild -particularly in the north (relative to the seasonal norm, that is). September 2006 was also very warm and it was succeeded by the mild, wet winter of 2006/07. During the last 30 years, since when the effects of global warming have become manifest in the British climate other warm Septembers followed by mild winters include 1989, 1998, 1999, 2004 and 2014. The reason for this is likely to be that some of the factors causing September warmth go on to contribute to a milder than usual winter. Above normal sea-surface temperatures in the NE Atlantic and reduced Arctic sea-ice extent in the Arctic both help steer the Circumpolar Vortex further north causing warmer airmasses to affect the UK, both these factors mean that airmasses affecting Britain from north and west will be warmer than usual. These influences will play out in any season of the year and so this will contribute to a correlation between September and the subsequent winter. With further climatic warming in future years we can expect the increased warmth of waters to our west and less ice in the far north to lead to warmer Septembers and some very mild winters. However, there have been occasions in the past whereby remarkable September warmth has actually been followed by a cold winter. A classic instance was September 1985, a month punctuated by long spells with very warm sunny weather which culminated in remarkable heat on 1st October; yet winter 1985/86 was bitterly cold (in particular February 1986 during which month bitterly cold easterlies brought snow and hard frosts). September and October 1978 were also warmer than usual and this was followed by the very cold and snowy 1978/79 winter. It really depends on what is causing a warm September as to whether one can be confident of a mild winter. If unusually warm waters in the NE Atlantic combined with vigorous hurricane activity in the tropics are the decisive influences, particularly at a time of high sunspot activity then yes, one could predict a mild winter. The very high specific heat capacity of even just the top 50 metres of the NE Atlantic means that anomalous warmth in September is likely to persist into winter and the Sunspot Cycle barely changes in the space of a few months, so both these factors will likely affect a September and the following winter months. On the other hand a warm September caused by a blocking high over Scandinavia bringing warm south-east winds and sunshine at a time of solar minima, strong easterlies in the equatorial Stratosphere and when sea-surface temperatures to north and west of Britain are colder would be much much less likely to indicate a mild winter! Quite apart from the fact that a blocking high is unlikely to persist for more than a few weeks, the same pattern of south-easterly winds over Britain caused by a block over Scandinavia tends to result in cold weather in the winter months rather than anomalous warmth (which could be expected from this pattern in September). Furthermore, if the Sunspot Cycle is at minimum and strong easterlies predominate in the Equatorial Stratosphere over prior months this tends to indicate a cold winter with plenty of blocking. This is especially true when these factors apply at a time sea-surface temperatures are below normal to the west and north of Britain.

@Johnp; I am sure it is not the intention of most of the weather-enthusiasts posting on the Stratospheric Watch thread to talk specifically about climate change. That said, any serious discussion about Stratospheric temperature and wind-patterns (which all have a major bearing on conditions down below) is going to involve those factors that are a major influence on the Stratosphere in such discussions. Examples include El Nino/La Nina which cause tropical convection anomalies and different levels of wave activity to reach the Stratosphere; gravity waves are caused by strong winds blowing over mountain ranges and these impact the Stratosphere; sunspot activity affects the magnetic field and the interaction with the magnetosphere results in an intensification of the Stratospheric polar vortex and factors such as ozone concentrations, dust from volcanoes, etc affect temperatures in the Stratosphere because more solar energy is absorbed and that, too, will affect wind-patterns. Atmospheric tidal influences from the Moon and the Sun also have a (small) effect on the Stratosphere, as do meteorites and atmospheric out-gassing to space (though again these effects are usually very small). Last but not least the large-scale atmospheric circulation of the underlying troposphere has an impact further up- extensive easterlies in the upper atmosphere over lower latitudes would slow down (and possibly reverse) Stratospheric Westerlies above them and this effect would spread into higher (and lower) latitudes. I hope that this answers your query.

It would seem that the dramatic weakening of the Westerlies of the sub-arctic Stratosphere at the start of February has not amounted to much; we have had a few days of easterly winds but no real low temperatures and snow (only got to -2C where I live in the North Pennines). Other factors, perhaps the unusual warmth of the far NE Atlantic and the effects of the strong Westerly QBO phase have meant that pressure has not remained high enough for long enough to the north of Britain to deliver real cold air to the entire country. However, predicted polar stratospheric warming at the 10 mb level is predicted to lead to a possible reversal of stratospheric Westerlies over the sub-arctic near the end of this month, vis: Lets see if this can result in some real cold-weather synopsis in early March 2017! If this month is anything to go by the effects of the unusual warmth of the far NE Atlantic and Westerly QBO (by then combined with the strengthening sunshine and lengthening days of March) could well mean persistent high-pressure in mid-latitudes- i.e. over Europe with lower pressure over the warmer far NE Atlantic leading to quite benign conditions instead. We shall see.

Rather surprisingly, in view of the predicted cold of the easterlies last week (and flagged up in long-range forecast models up to three weeks earlier) the spell of easterlies has proved to be a damp squib- even where I live at over 400 metres' elevation in the North Pennines: Only four inches of rather wet snow to show for it late yesterday afternoon and at no point has the air temperature dropped below -2C (and has not since the start of February). The high-pressure that was over Scandinavia is slipping southwards and the winds here have turned south-easterly bringing air from the Med rather than icy eastern Europe- today the thaw has set in. Mild south-westerlies and westerlies look like resuming control of the weather in the next few days and they look set to remain in place through to the month's end. So glad I am off to Canada in a few days!

@cheeky_monkey, I sincerely hope the warmer air does not reach Churchill! I will have spent upwards of £ 1500 to get my frosty snowy fix- so I would not be happy for my stay there to coincide with mild south-westerly winds and their mildest part of the winter. South-westerly winds would be dry (having traversed the USA east of the Rockies and southern Canada before reaching that region), so even if the air arrived at just below freezing point they would not bring much snow. Also I would be so disappointed to have travelled thousands of miles to experience nothing below -5C for the duration of my time at Churchill. Let's hope that I am not disappointed to such an extent because it would be a big waste of my money.

Nice to see that there is likely to be decent snow-cover (and some very low temperatures) for my holiday in Canada commencing a week today. I will be travelling to Churchill with my brother, on the western coast of Hudson Bay (which is frozen over). I will also be taking a thermometer with me so I can record some (hopefully) very low temperatures. Winter 2016-17 has been a write-off as regards severe cold and snow where I live; hence I have to go elsewhere to seek my very frosty snowy fix!

@Weather-history; Certainly for the north and west of Britain it does not seem to have been a cold winter to date. Where I live in the North Pennines I am yet to see the temperature drop below -5C (unusual for us at over 400 metres above sea-level not to get below this temperature) and we have only had 8 cm of snow-cover at most. The high-pressure systems this winter have tended to be over Europe, sometimes extending across the South and this is not a good position for very cold conditions with hard-frosts for the North Pennines. This part of the country has often had mild air off the North Atlantic whilst the South East has had dry cold and frosty weather under high-pressure. That said, the (predicted) circulation far aloft over the Arctic and sub-arctic gives more grounds for optimism (as regards cold weather and snow) over the next fortnight and certainly for those of us living in the north of England the longer-term forecast charts (which have strong high-pressure over Scandinavia) there are prospects for the coldest weather this winter to date. In early January the predicted mean winds at 10 mb were over 30 m/s (67 mph or more) along 60N and the strong westerly QBO high over the Equator looked like it might help maintain the strong upper flow; thanks to upwards wave activity over the tropics associated with convective disturbances (leading to subsidence and warming in the Arctic Stratosphere) since early January the 10 mb level westerlies averaged along 60N are now much weaker ( and predicted to remain so) leading to the surface synoptic set-up with high-pressure over Scandinavia expected this week. if it comes off I, for one, will be quite chuffed!

@Weather-history; Certainly the QBO phase is not the only factor and I do not mean to suggest that this is so. It is certainly, on the other hand, an important factor- along with the El Ninó/La Niná phase, the stage of the Solar Cycle; the period you refer to of 1988 to 1992 occurs during and just after the peak of Schwabe Cycle 22- the previous Solar Cycle but one- an active Sun with more sunspots and solar flares promotes a stronger Circumpolar Vortex in higher latitudes through interaction with Earth's magnetic field (this would also help explain some of the mild winters over Britain at that time despite easterly QBO phases). Also very relevant for NW Europe are sea-surface temperatures over the North Atlantic and the extent of Arctic ice-cover, not to mention factors such as winter snow-cover and the consequent entrenchment of frigid conditions over Eurasia and indeed North America (when these conditions encourage the expansion of the Circumpolar Vortex with the displacement of the jet-stream into lower latitudes this greatly increases the likelihood of cold weather over Britain in the winter months). I am confident that, over the next few winters that the trend towards a very inactive Sun, with the QBO being turning easterly and the right ENSO conditions (weak-moderate El Ninó) will help to set the scene for another major winter cold spell in Britain (by which I mean most locations dropping well below -10C and staying below freezing point for a week or more). A major volcano in the tropics over these next few years would be a Godsend in that regard because it would provide further assistance towards creating conditions for severe winter cold in western Europe: It would do this by warming the Stratosphere and cooling the low troposphere (due to dust and sulphur dioxide): That would weaken the Hadley Circulation and sharply reduce the regular production of Westerly Atmospheric Angular Momentum that ends up powering the higher-latitude Westerlies in the winter months- ergo weak Westerlies and high-latitude blocking bringing severe winter weather from Russia or the Arctic towards the UK.

@Man With Beard; I do actually hope that this Scandinavian blocking-pattern comes off because for where I live, at over 400 metres' elevation in the North Pennines (a location where in a typical winter we would expect extreme minima down to -8C and over thirty days of snow-cover) it has been a thoroughly naff winter! Even on the highest part of the North Pennines (Cross Fell at almost 900 metres' elevation) there is scarcely any snow lying at present and tomorrow is 1st February! We could well do with some proper winter weather-excitement for a change. Real snow and low temperatures. The developments aloft high over the Arctic do in that regard offer some grounds for optimism (though not massively so, the mean wind-speed at 10 mb and 60N is still-just- westerly at its weakest)!

@Harsh Climate; Indeed, chart-watchers can tie themselves in knots looking a depressions crossing the North Atlantic and high-pressure cells over Spain: This is part of the prevailing climate of NW Europe with a prevailing wind from the south-west! Current and predicted developments in the Arctic Stratosphere (and predicted up to a week into the future with considerable reliability nowadays), and which take two to three weeks to fully manifest at the surface give a better general outlook for two or more weeks out. Beyond that, the state of the Quasi Biennial Oscillation (the alternating pattern of east then westerly winds high up above the Equator), the state of the Sun, El Ninó/La Niná and patterns of sea-surface temperature in the North Atlantic and Arctic pack-ice extent are the parameters I use in making seasonal forecasts- with some measure of reliability. I know from bitter experience not to look at weather charts predicted more than a fortnight out. One is liable to be disappointed!