Winter 2016/2017: Preliminary Prediction

[I remember Atlantic 252]

19 hours ago, Ice Day said:

OK, time to nail my colours to the mast.  Here's my thoughts on Winter 2016/17 (I'm completely unqualified but very keen!!!)

November - Temps slightly below average along with lower than average rainfall.  No UK notable snow events

December - First half of the month, above average temps in the south, average in the north along with average rainfall.  Second half of December will bring a rapid cool down with significant snowfall in Scotland and Northern England (lump on a white Christmas in these areas!).  Below average temps in the south but mainly dry.

January - A significant nationwide snow event will take place in the first half of the month emanating from a northerly that swings north easterly finally around to a full blown beasterly.  Second half of the month will be colder than average but dry.

February - Starts off benign but becomes a very stormy month (the Atlantic has to kick in eventually).  Above average temps and rainfall.

 

What can go wrong?

 

Feb, I think you could be close!

[Radiating Dendrite]

So you will stick by your forecast for the rest of winter come December 1st?

[Nick B]

2 minutes ago, Radiating Dendrite said:

So you will stick by your forecast for the rest of winter come December 1st?

I'm not sure that's entirely fair! 

Ian needs no defending in here from the likes of me, my observation has been however that he states his opinions which are inevitably backed up with reasoning.  No-one can be in possession of all the facts with something so mobile.  I think it's obvious that Ian goes into details which may risk being proved wrong by subsequent events, however he does this in the full knowledge that this can and will happen - always.  My impression is that when he issues a forecast, in a sense it is a marker stuck in the ground, so that as events unfold the forecast can then be measured in order to gain further understanding of the factors influencing real events.  This is open, courageous and humble and, in particular, is a wholehearted scientific endeavour.  Hence his entirely correct reasoning for his change in position recently.

[lassie23]

November cool and unsettled becoming stormy towards the end

December, stormy start, calming down but the first proper hit of winter mid December and over christmas

January starting cold but becoming stormy until then end of the month

February a cold snowy month with winds mostly from the east

March who cares, it's spring

[Methuselah]

2 minutes ago, lassie23 said:

November cool and unsettled becoming stormy towards the end

December, stormy start, calming down but the first proper hit of winter mid December and over christmas

January starting cold but becoming stormy until then end of the month

February a cold snowy month with winds mostly from the east

March who cares, it's spring

I'm soon to be getting a cat!

[lassie23]

1 minute ago, Ed Stone said:

I'm soon to be getting a cat!

woohoo, mine makes a great foot warmer when she sits on them in the winter.

[I remember Atlantic 252]

2 hours ago, lassie23 said:

November cool and unsettled becoming stormy towards the end

December, stormy start, calming down but the first proper hit of winter mid December and over christmas

January starting cold but becoming stormy until then end of the month

February a cold snowy month with winds mostly from the east

March who cares, it's spring

Dec, mainly mild and wet, PM air at times giving snow to hills, above average rain and temps

Jan, mainly mild, Atlantic lows to dominate, snow at times in Scotland as lows move away in the PM air, flooding possible, above average temps and rain

Feb, less mild generally, coolest month of the winter, snow down to low levels in the north during PM shots, wet, but not as wet as Dec and Jan

[moorlander]

12 minutes ago, I remember Atlantic 252 said:

Dec, mainly mild and wet, PM air at times giving snow to hills, above average rain and temps

Jan, mainly mild, Atlantic lows to dominate, snow at times in Scotland as lows move away in the PM air, flooding possible, above average temps and rain

Feb, less mild generally, coolest month of the winter, snow down to low levels in the north during PM shots, wet, but not as wet as Dec and Jan

Noooooooooooooooooooooooooooooooooooo

I hope you are so wrong, cant take another Winter like that

[I remember Atlantic 252]

1 minute ago, moorlander said:

Noooooooooooooooooooooooooooooooooooo

I hope you are so wrong, cant take another Winter like that

you might be okay, peaks look good for snow in that setup, but thawing as mild sectors move through

[Hocus Pocus]

Don't get me wrong I'm not having a dig at you Ian and you're quite right it says it on the tin " preliminary ", but the facts are you were very descriptive in how you felt it was likely to play out and I'm merely suggesting (  not that I'm some sort of weather guru or expert ) that October is far too early for such in depth details. 

[Daniel*]

Personally I can't see how we can avoid a cold December.

December - cold dominated potentially very cold precipitation around average perhaps below average to the west - this largely falling as snowfall away from the far southwest. Decent snow events with channel runners.

January - first half bitterly cold beast from the east, severe cold on the continent perhaps lapping into southeast - by mid month mobility somewhat resumes with Atlantic wanting to pounce in. Battle ground scenario. Mild eventually winning out. Overall colder than average. 

February - I expect the polar vortex to have strengthened significantly - wettest month of the winter, largely southwesterly dominated. I think March might be chilly. 

A decent winter for snow across the south best since 2010...although a somewhat subdued second half that is my feeling with the disturbed vortex not staying that way - and perhaps an increase in solar activity scuppering another decent cold spell. 

Edited November 3, 2016 by Changing Skies.

[iapennell]

15 hours ago, Hocus Pocus said:

Don't get me wrong I'm not having a dig at you Ian and you're quite right it says it on the tin " preliminary ", but the facts are you were very descriptive in how you felt it was likely to play out and I'm merely suggesting (  not that I'm some sort of weather guru or expert ) that October is far too early for such in depth details. 

In which case, why would one try to make predictions for the season ahead?!! The fact remains, that there are several macro-scale pointers (that are very unlikely to change in the space of a few months), like the El Nino Cycle, the wind-pattern high over the Equator (Quasi Biennial Oscillation), pronounced sea-surface temperature anomalies north and west of Britain (and where these are) along with marked seasonal Arctic sea-ice anomalies not to mention where we are in the Sunspot Cycle that tend to hold true over longer periods of time that one can use to make a prediction. That is not to say unforeseen events cant or wont knock the prediction off course, but using the macro-scale variables to make predictions for the season ahead (particularly for a season in which the Circumpolar Vortex is liable to settle into a particular pattern and stay there- and one can ascertain where the likely baroclinic zones affecting it, and therefore the storm-tracks will be) is likely to produce more accurate forecasts over the long term than going by more transient features like blocks on weather charts.

That's not to say weather charts and model runs up to three weeks out are not valuable, particularly on approaching the beginning of our predicted season, but they tend to show up to three weeks ahead at most. Blocking highs over Scandinavia in themselves can encourage cold and snow-cover over Europe that might lead to a tweaking of the early part of a seasonal prediction in a colder direction; but both the block and European snow-cover are transient features that can be swept away should the Circumpolar Vortex strengthen, the Rossby Wave pattern shift east to place an upper trough just west of Norway and milder south-westerlies remove the European snow-cover! Even the forecast models can get these wrong! However, strong sea-surface temperature anomalies, El Nino Oscillations and high-latitude sea-ice anomalies almost never change that quickly (owing to the very large specific heat capacity of oceans) so they can be relied upon more in making seasonal predictions.  

[chrisbell-nottheweatherman]

20 hours ago, I remember Atlantic 252 said:

Dec, mainly mild and wet, PM air at times giving snow to hills, above average rain and temps

Jan, mainly mild, Atlantic lows to dominate, snow at times in Scotland as lows move away in the PM air, flooding possible, above average temps and rain

Feb, less mild generally, coolest month of the winter, snow down to low levels in the north during PM shots, wet, but not as wet as Dec and Jan

Reverse the order, and that would be pretty close to my own best guess.  I suspect a milder, wetter and windier winter than average, but with December being the chilliest month.  With the exception of the Welsh mountains and (possibly) the moors of the south west, I do not anticipate any lying snow south of the Peak District.

[Guest]

1 hour ago, chrisbell-nottheweatherman said:

Reverse the order, and that would be pretty close to my own best guess.  I suspect a milder, wetter and windier winter than average, but with December being the chilliest month.  With the exception of the Welsh mountains and (possibly) the moors of the south west, I do not anticipate any lying snow south of the Peak District.

I would take that....lol... i really do feel tho that the UK is due a proper winter spell... we have spent the last 3 winters looking over at the USA dreaming of what they have had etc... im sure its our turn this winter the NH is massively different to what we have seen in the last few winters and that must hold promise for the next few months at least... im thinking front loaded winter followed by a warm up then a big winter spell to go out on... and lets remember its still very early days... i remember we had an overnight snow fall here last November think it was the 16th and we all got happy thinking it was a sign of what the winter would hold... we had 24 hours of lying snow last winter and that was so marginal we just got lucky... if it gets to the end of January and things still have not happened then by all means start to panic...

[mcweather]

4 hours ago, iapennell said:

In which case, why would one try to make predictions for the season ahead?!! The fact remains, that there are several macro-scale pointers (that are very unlikely to change in the space of a few months), like the El Nino Cycle, the wind-pattern high over the Equator (Quasi Biennial Oscillation), pronounced sea-surface temperature anomalies north and west of Britain (and where these are) along with marked seasonal Arctic sea-ice anomalies not to mention where we are in the Sunspot Cycle that tend to hold true over longer periods of time that one can use to make a prediction. That is not to say unforeseen events cant or wont knock the prediction off course, but using the macro-scale variables to make predictions for the season ahead (particularly for a season in which the Circumpolar Vortex is liable to settle into a particular pattern and stay there- and one can ascertain where the likely baroclinic zones affecting it, and therefore the storm-tracks will be) is likely to produce more accurate forecasts over the long term than going by more transient features like blocks on weather charts.

That's not to say weather charts and model runs up to three weeks out are not valuable, particularly on approaching the beginning of our predicted season, but they tend to show up to three weeks ahead at most. Blocking highs over Scandinavia in themselves can encourage cold and snow-cover over Europe that might lead to a tweaking of the early part of a seasonal prediction in a colder direction; but both the block and European snow-cover are transient features that can be swept away should the Circumpolar Vortex strengthen, the Rossby Wave pattern shift east to place an upper trough just west of Norway and milder south-westerlies remove the European snow-cover! Even the forecast models can get these wrong! However, strong sea-surface temperature anomalies, El Nino Oscillations and high-latitude sea-ice anomalies almost never change that quickly (owing to the very large specific heat capacity of oceans) so they can be relied upon more in making seasonal predictions.  

Hi Ian I always take time to read your forecasts and admire the effort you put in and the fact that you attempt to back it up with some science.

I do have to say that I feel you offer some hostages to fortune with some of the detail that you try to give so far ahead.

I wonder have you applied your system to hindcasting some of our colder winters like 2008/9 2009/10 to see what you would have forecast, and bearing in mind the detail that you tend to put in wwhether you would have picked up the severe cold spell of late November/December of 2010 for instance.

 

[iapennell]

On 11/4/2016 at 19:25, mcweather said:

Hi Ian I always take time to read your forecasts and admire the effort you put in and the fact that you attempt to back it up with some science.

I do have to say that I feel you offer some hostages to fortune with some of the detail that you try to give so far ahead.

I wonder have you applied your system to hindcasting some of our colder winters like 2008/9 2009/10 to see what you would have forecast, and bearing in mind the detail that you tend to put in wwhether you would have picked up the severe cold spell of late November/December of 2010 for instance.

 

@mcweather, Interesting to go back through the archives to see whether I would have predicted recent cold winters: In October 2008 there was cooler-than-normal waters just west of the UK but warmer than usual to the north, the Arctic ice extent was below the long-term norm but not so much as this autumn and there was a pronounced Lá Nina in the Equatorial Pacific. I would have predicted a more northerly path of storm tracks based on warm waters in the sub-arctic but with Arctic pack-ice not much below normal still likely to get very cold (over the ice) and generate strong baroclinicity along the margin of the pack-ice. The QBO was positive (Westerly) at the time.

However, cooler than usual waters just west of Britain predicated high-pressure being more likely to occur there and Lá Nina suggests weaker NE Trade Winds over the Pacific. There was also a BIG increase in north America and Russian snow-cover in autumn 2008 and also the previous Sunspot Cycle was falling away. On the basis of all these pieces I would have predicted a slightly colder than average winter, most storm-tracks liable to pass well north of Britain (but not all of them) with plenty of dry frosty weather but also some mild wet spells. I would have expected some high-pressure to push in from Russia to bring very cold air off frozen snow-covered Eurasia but not to a great extent.  The Westerly QBO would have got me thinking that that would affect Britain later in the winter (bringing strong westerlies), I would probably not predicted the very cold and snowy start to February in 2009.

In October 2009 the mid North Atlantic was slightly cooler than average but waters north of Britain were 2 to 3C warmer than normal for October. Arctic ice was well below normal and this would have predicated strong storm tracks in winter over or possibly north of Iceland but with the cool mid North Atlantic (slightly) increasing the likelihood of high-pressure there. However, in autumn 2009 there was by then a weak El Nino and snow-cover over Russia and North America had not increased to the extent it had in autumn 2008. More than outweighing these were the very quiet state of the Sun and the fact that the QBO was strongly easterly (mean wind-speeds up to 30 mph) at the 30 mb level. On balance, and given the temperature of the ocean surfaces north of Britain I would have gone for a drier than usual winter with temperatures only a little colder than normal because the pattern of sea-ice/warmer than usual water to the north would have indicated to me stronger storm tracks towards the Arctic that would largely have prevented Arctic air reaching Britain. I would have expected however, from the cool waters just west of Britain, that there would be an increased chance of spells with bitterly cold high-pressure from Russia due to the southern portion of the jet-stream splitting and carrying some depressions into the Med leaving open the possibility of the Siberian High extending westwards.

In 2009, after over 20 years without really severe winter weather, I had come to believe that because of the somewhat reduced extent of Arctic ice combined with warmer than usual seas north of Britain that really hard winters were unlikely to occur again barring some major disruption like a thermohaline shutdown in the North Atlantic or a powerful volcano or two. That's what I believed then and if I am honest, I would not have predicted 2009/10 to be really cold based on the sea-surface temperatures, ice-cover extent, snow-cover over land, etc.

In autumn 2010 the QBO had been strongly Easterly and only became weak westerly by September by which time Lá Nina was setting in in the Equatorial Pacific (following a strong El Nino earlier in the year). The Sun, at the end of the last Sunspot Cycle at that time was very quiet- all pointers to a cold winter with plenty of blocking (at least in the early half- as the residue of Easterly QBO worked out of the Northern Hemisphere circulation). However, in October 2010, although there was extensive snow-cover over Eurasia, sea surface temperatures to the west and north of Britain were well above average for the time of year but there was cooler than normal water off the USA East Coast. Arctic sea-ice was below normal but not unusually so- strong baroclinic gradient between warm sea and very cold Arctic not far from Iceland and I would have predicted January/February 2011 to have been mild and stormy on that basis (true for February 2011). I would have expected cold spells during the early part of the winter- probably from the east but nothing as severe as actually happened and I would have anticipated mild wet spells that for November/December 2010 based on the anticipated strong baroclinic zone around Iceland (early November 2010 was indeed very wet- the SSW that occurred over the Arctic later meant that the weather later became much colder as winds turned north-easterly).

I hope this answers your question.   

[iapennell]

Quasi Biennial Oscillation average for October shows further increase in the mean strength of the Westerlies (to 12.9 metres per second), Arctic sea-ice at record low for early November but slowly increasing and sea-surface temperatures above normal to the north of Britain: Westerlies to the north augmented by likely baroclinicity Canada/Greenland-far North Atlantic and also (later) by the signal from QBO. I would re-iterate that I do not expect really severe and/or prolonged cold in January/February 2017- even though cold water patch in mid North Atlantic could result in the splitting of the Circumpolar Vortex at times with one part moving south-east over the Med at times.  

[lassie23]

12 minutes ago, iapennell said:

Quasi Biennial Oscillation average for October shows further increase in the mean strength of the Westerlies (to 12.9 metres per second), Arctic sea-ice at record low for early November but slowly increasing and sea-surface temperatures above normal to the north of Britain: Westerlies to the north augmented by likely baroclinicity Canada/Greenland-far North Atlantic and also (later) by the signal from QBO. I would re-iterate that I do not expect really severe and/or prolonged cold in January/February 2017- even though cold water patch in mid North Atlantic could result in the splitting of the Circumpolar Vortex at times with one part moving south-east over the Med at times.  

That is disappointing, seem to be stuck in a pattern of mild winters at the moment, is there no end in sight?

[Rollo]

Disappointing indeed but the weather will do what the weather wants and IMO (uneducated as it may be) ,I still hold out some good thoughts for at least the first part of winter proper.

[ArHu3]

21 minutes ago, iapennell said:

Quasi Biennial Oscillation average for October shows further increase in the mean strength of the Westerlies (to 12.9 metres per second

But the QBO has become unpredictable, we don't know why it didn't follow its regular rhythm

[Nouska]

33 minutes ago, iapennell said:

Quasi Biennial Oscillation average for October shows further increase in the mean strength of the Westerlies (to 12.9 metres per second), Arctic sea-ice at record low for early November but slowly increasing and sea-surface temperatures above normal to the north of Britain: Westerlies to the north augmented by likely baroclinicity Canada/Greenland-far North Atlantic and also (later) by the signal from QBO. I would re-iterate that I do not expect really severe and/or prolonged cold in January/February 2017- even though cold water patch in mid North Atlantic could result in the splitting of the Circumpolar Vortex at times with one part moving south-east over the Med at times.  

The 30mb measure of the equatorial stratosphere might be stuck in a westerly phase but don't ignore the two standard deviation to climatology that is going on in the zonal mean wind at the 10mb level in the arctic . Easterly phase also dominates below 50mb level.

A highly disrupted profile can not be relied on for forecasting anything this coming winter.

Edited November 7, 2016 by Nouska

[Methuselah]

I'm not at all disappointed:

No disrespect meant, but I don't give anyone's winter-forecasts much more than a cursory glance, these days...Usually, form my experience anyway (and the UK's default winter climate notwithstanding) they are almost all wrong?

There's a hint there as to why I gave up LRFing!

[Rollo]

Ed I too gave up LRF's many years ago, not because I got egg on my face but the fact it is so easy to look foolish after the event, my forecast was for many reasons was pretty accurate but I put that down to luck. For your info I repeated on a local BBC TV station.

[iapennell]

On 11/7/2016 at 14:58, Nouska said:

The 30mb measure of the equatorial stratosphere might be stuck in a westerly phase but don't ignore the two standard deviation to climatology that is going on in the zonal mean wind at the 10mb level in the arctic . Easterly phase also dominates below 50mb level.

A highly disrupted profile can not be relied on for forecasting anything this coming winter.

A look at the QBO at the 50 mb level (lower down in the Equatorial Stratosphere) shows that this, too, has become Westerly as averaged over the last month (average for October 1016):

https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwigx6Th8KDQAhVKBsAKHVMbDWcQFggwMAA&url=http%3A%2F%2Fwww.cpc.ncep.noaa.gov%2Fdata%2Findices%2Fqbo.u50.index&usg=AFQjCNHz_FLh4h2v0CwU-FxJAAf2pd5Jeg

Given the fact that October's QBO average at the 30 mb level was also 12.9 m/s from the West (about 29 miles per hour), this is not something that can be discounted.

Now,IF ONLY both the 50 mb and 30 mb QBO's had averaged 10 metres per second (or above) from the East: then I'd say, what with the extensive Eurasian snow-cover we have combined with the Lá Nina in the Equatorial Pacific- then we could be talking!!

Unfortunately, that is not the case and you can see (comparing the Stratospheric winds at the 50 mb and 30 mb levels) how the Westerliness of the QBO is working down through the Stratosphere. When it reaches into the Equatorial Troposphere it quickly gets into the Global Circulation providing an extra source of Westerly AAM. You can appreciate from this why I am not predicting a cold and snowy winter for the UK. Of course, a number of factors impact upon the strength of the Westerlies in higher latitudes and thence on the British winter weather that we can expect but the QBO is a pretty major influence. Furthermore, the patterns of sea-ice extent and ocean-surface temperature anomalies indicate to me where the likely sinks for excess Westerly AAM are going to be at the surface; Arctic sea-ice is slowly recovering from it's record Autumn lows and over the newly formed pack-ice it will, of course, get very cold and this will propagate up into the Arctic atmosphere making that very cold (and reducing thickness heights over the Arctic in the process). Over the warmer-than-normal North Atlantic and North Pacific waters on the periphery surface air and air higher in the atmosphere is warmer and thus thickness heights will be higher and between the two will be a substantial baroclinic temperature and pressure gradient: What does that tell you about the likely passage of depressions?

What I take away from the facts about the QBO is that there is a major store of Westerly AAM, currently in the Equatorial Stratosphere, this is slowly working it's way towards the Equatorial Troposphere from where it will quickly enter the Northern Hemisphere General Circulation. The increasing strength of the NE Trade Winds going into winter will increase the uptake of Westerly AAM for the Northern Hemisphere General Circulation as a whole, this fairly quickly leads to an increase in the speed and strength of the upper Westerlies further north and if baroclinic factors concentrate this towards the northern North Atlantic (as seems likely this coming winter) then we can kiss good-bye to high-latitude blocking by January.

However, there is a small caveat (or consolation!) caused by the rapid increase of scow-cover over Eurasia that could alter the scene quite dramatically: Increased snow-cover over central Asia would increase the surface albedo locally resulting in further regional cooling beyond the normal seasonal cooling that occurs- and crucially this leads to reduced mid-tropospheric thickness heights north of the Himalayas and the Central Asia Pamirs. That in turn would increase the strength of the high-level Westerlies that would then blow strongly against the highest parts of these mountain ranges (these mountains, rising to 7,000 metres or higher) are not far beneath the sub-tropical jet-stream (which itself would be strengthened, displaced equator-ward a little and further reduced in altitude by the effect of extensive snow-cover further north). The strengthening NE Trade Winds (whose frictional interaction with the underlying surface leads to an increase in Westerly AAM for the Northern Hemisphere as a whole) combined with Westerly AAM coming from high-up over the Equatorial Stratosphere would also help strengthen the subtropical jet and assist possible cyclogenesis over Central Asia= between the snow-covered rapidly-cooling North and the still-warm subtropics. The resultant Westerlies would be very strong over these mountains (easterlies north of such depressions would be weak aloft). Thus the Himalayas and Pamirs could well become a major sink for Westerly AAM which would mean less need for strong Westerlies over the North Atlantic and North Pacific with, for the United Kingdom, much greater scope for cold dry high-pressure conditions from northern Europe to affect the winter weather.

Because of all this, I very much believe this coming winter will certainly be colder than last winter overall, but there is no way I would predict a deep-freeze for either January or February. Likewise there will be much less rain this coming winter (probably more snow for most) but there will still be wet and windy spells across the country. And the effects of rising Westerly AAM in the Northern Hemisphere Circulation (from the effects of the NE Trades and Westerly QBO reaching downwards over the Equator) will be felt in the UK soon- at any rate by the middle of the next month: Of that, I can be sure! 

[iapennell]

BTW  do any of you know about Accounting? I know this is a strange topic to bring up on this Forum but I am currently studying AAT Advance Diploma in Accounting and are familiar with how assets, liabilities, capital, expenditure and income are accounted for: A business is healthy with good prospects if it has lots of assets, has goodwill and is profitable- any Accountant will tell you this. Likewise, as you can divide money up this way, there are parralels as to how heat and momentum can be divided up.

So then, we have a situation where large amounts of heat are stored in the oceans at higher latitudes, the Northern Hemisphere has been (overall) absorbing more heat than it has lost over several years and there is a large amount of this heat stored into the oceans-particularly just west and north of Britain and this country is likely to be a benefactor of this stored heat in the coming months as it is released into the atmosphere.

Overall, thanks to the laws of Conservation of Angular Momentum, the Earth-Atmosphere system only leaks very small amounts of momentum to Space (chiefly through out-gassing and marine/atmospheric tidal friction due to the Sun and the Moon- the latter being much more important). However, to follow the Accounting analogy Westerly AAM as transferred between and stored in different Ledgers": In this case these ledgers would be the solid Earth, the oceans, the Troposphere and the Stratosphere/Mesosphere and with regards to the surface Easterlies are expenditure and Westerlies income. When excess Westerly AAM is stored in the Troposphere or in the stratosphere (i.e. Westerly QBO's) and there is a strong transfer of Westerly AAM into the atmosphere at low latitudes increasing this store, the atmospheric ledgers of Westerly Momentum would soon be bursting to the brim: As such these factors increase the prospect for Westerly AAM to be returned to the surface (using Accounting analogy there are assets and money in the bank for a businessman to draw upon for personal use). This only happens if there are Westerlies interacting with the underlying surface with the frictional impact with these causing a loss of Westerly AAM.

In other words, I hope that you can appreciate why both the heat and momentum budgets are such the they don't point to a hard winter in Britain.