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SPRING 2016: UNSETTLED


iapennell

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Posted
  • Location: Alston, Cumbria
  • Weather Preferences: Proper Seasons,lots of frost and snow October to April, hot summers!
  • Location: Alston, Cumbria

I am offering my provisional outlook for Spring 2016 for the United Kingdom. In some ways the spring and summer are harder to forecast from a month or more out than winter because the Circumpolar Vortex weakens in spring; this makes it prone to sudden flips and higher latitude blocking-patterns which can cause remarkable changes in prevailing weather patterns in the space of a few days. That said, there are enough of the pan-regional temperature and circulation anomalies to gain some insight into the processes likely to affect the weather in coming months. 

Firstly El Nino: This is still in a positive phase with very warm water stretching to coastal Peru and Ecuador.  This means the ITCZ remains strong and that will maintain strength in the NE Trade Winds in the tropical North Pacific. This implies a need for stronger Westerlies at higher latitudes to satisfy conservation of angular momentum laws.

Secondly there is now a sizeable pool of really cold water in the mid NW Atlantic (this water gets really cold by February anyway but it is colder than normal by up to 3C) but the NE Atlantic is warmer than the seasonal norm (but not by a lot). Arctic Ice extent is less than normal in the Eurasian Arctic but extending a bit further south than normal around Newfoundland and of course Greenland and NE Canada are very cold indeed at present.

Third, the QBO high over the Equator remains in Westerly Mode and we are still in active phase of the current Sunspot Cycle (Schwabe Cycle number 24, I do believe). We can now put the pieces together to arrive at a prediction:

cont'd below 

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Posted
  • Location: New Forest (Western)
  • Weather Preferences: Fascinated by extreme weather. Despise drizzle.
  • Location: New Forest (Western)

I appreciate the effort that has been put into this forecast, however I do find the wording way too confident for my liking. For example, there are enough signs of significant MJO influence early March, which may change the AAM picture considerably, that a predominantly westerly pattern is far from assured.

To be fair, the composites for the past two super El Ninos do offer good support the westerly theme when the MJO is quiet:

BRuEb5uVgV.png fIUAomZcZf.png

...although this year's event is rather different in some ways due to anomalous warmth in the Indian Ocean plus an increasingly 'Central Pacific' or 'Modoki' tendency to the SST and convection anomalies.

In fact the peak anomalies are now around 145W. In 1983 they were at about 130W in Feb which is a considerable difference.

MLPCSJ3Rdh.pngsst.anom.gif

It will be interesting to see what consequences this has on the Trade Winds for example. 

 

 

 

 

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Posted
  • Location: Nymburk, Czech Republic and Staines, UK
  • Weather Preferences: Sunny and warm in summer, thunderstorms, snow, fog, frost, squall lines
  • Location: Nymburk, Czech Republic and Staines, UK

An interesting analysis/prediction. Hopefully not all correct though. Some warmth and sunshine would be preferable to snow in April!

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Posted
  • Location: Austevoll Kommune North of 60 deg N
  • Weather Preferences: Cold with a metre of lying snow
  • Location: Austevoll Kommune North of 60 deg N

..... and we are still in active phase of the current Sunspot Cycle (Schwabe Cycle number 24, I do believe).

Ian,

Can you explain the phrase " active phase" in the above please?

Yes, we are in Cycle number 24 and heading towards a solar minimum in 2019.

Cheers

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Posted
  • Location: Truro, Cornwall
  • Weather Preferences: Winter - Heavy Snow Summer - Hot with Night time Thunderstorms
  • Location: Truro, Cornwall

Not great for warmth and sunshine it seems. Same as last few years. Any bets summer will go down the same route? Lol.

looks like April may save the spring again a little. Predictable!

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Posted
  • Location: Bude
  • Weather Preferences: Extreme weather...heavy snow and heat waves
  • Location: Bude
4 hours ago, Hocus Pocus said:

Another fascinating read Ian and I for one am sold on your methodology  despite being very sceptical in the beginning. :)

 

4 hours ago, Hocus Pocus said:

Another fascinating read Ian and I for one am sold on your methodology  despite being very sceptical in the beginning. :)

I echo this statement. Your methodology is most accurate than anywhere else I have seen

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Posted
  • Location: Bristol/South East
  • Location: Bristol/South East

But taking into account the AAM as Singularity pointed out and the fact that the PV will get weaker and weaker, realistically how much longer can an Atlantic dominated weather set up prevail? 

I think spring will start off unsettled if February really does turn out to be a stormy month throughout and gradually improve as the Atlantic quietens down and that we may see more rainfall but sporadically especially in the South with longer interludes of drier, useable (but perhaps colder in the North and Scotland) weather. But I don't see Spring being the relentless onslaught of storms and gales that Winter mostly was/is. 

Edited by wishingforsnow
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Posted
  • Location: Alston, Cumbria
  • Weather Preferences: Proper Seasons,lots of frost and snow October to April, hot summers!
  • Location: Alston, Cumbria

Thanks for the vote of confidence, though I have to confess that making a successful Spring prediction is harder because of the weaker Circumpolar Vortex.  The only reason I can make this prediction is that there are macro-scale controls on the large-scale wind-patterns likely to keep the Westerlies stronger (and more predictable) than normal for the season: That is a basis for predicting strong cold West and North West winds earlier in the spring, the unusually cold sea surface temperatures in the North Atlantic also gives me some confidence in predicting the latter part of the spring too- the positions of upper troughs and high-pressures will be modulated by this large patch of unusually cold water and when westerly winds blow over Britain later in the season they will have blown across a North Atlantic over 2C colder than usual over a wide area- this will (naturally) bring mean temperatures down.

I have had a check on the North Atlantic sea surface temperature anomalies and it now seems that a sizeable proportion of the ocean surface- particularly west of 15W and northwards of 40N is considerably colder than normal.  With the Circumpolar Vortex still likely to be strong through to April and the seasonal warming of continental Europe likely to be underway during March (currently much of Europe as far as Moscow is above freezing point) the trough associated with the Circumpolar Vortex that is normally over eastern Canada and the NW Atlantic is likely to shift further east than normal.  One can be confident that there will west and NW winds in March 2016 that will be cold, that these are likely to bring snow and night frost at times to northern Britain.

Later in spring, as the Arctic warms somewhat (likely to be helped by ice-cover being at lower than normal extent overall, though not in the Canada/Greenland sector) and the NE Trade Winds weaken in response to strong spring insolation over subtropical continents weakening the subtropical highs both baroclinic and angular momentum conservation influences will weaken the Circumpolar Vortex substantially and with it the higher-latitude Westerlies. The influence of the cold North Atlantic may well then come into its own then, but the point I made above about the weaker upper Westerlies of late spring being liable to "flip" quickly in unpredictable ways does mean that I am not so prepared to bet my life savings on a warm sunny spell in late April in the South or a cold wet May across most of the country: This is, alas, the most likely outcome as far as I can make out from studying the fundamentals. 

What is much more certain about late spring 2016 is that there will be a number of short spells with markedly different weather types which, against a measure of confidence in chillier and unsettled conditions rather than warmth, means I am certain of at least one spell with very cold weather (for the time of year) in late April or early May which will bring snowfalls to the North and night frosts across the country.  It is possible that the upper troughs caused by the cold North Atlantic remain west of the United Kingdom a couple of times during May in which case it will remain unsettled but warm southerly winds will bring temperatures above 20C to the South, though with an upper trough to the west we will not get wall-to-wall sunshine and blazing heat.  However, the Circumpolar Vortex usually becomes weak enough for it to segue from the two-three wave pattern of winter into a four-wave pattern by May: With an upper-ridge locked to the Canadian Rockies by then (normally the case but the so-called "topographical locking" of the Circumpolar Vortex has less control as the upper winds weaken) a four-wave pattern would place a trough over the United Kingdom; colder-than-normal waters over the North Atlantic would reinforce troughing over and downwind of the cold ocean surfaces. For these reasons I am prepared to predict with some confidence that (on the whole) May 2016 will be colder than normal across the country. This does not mean every day will be cold and wet for the time of year; given the sharp variations likely from one week to the next there will be some warm sunny spells but these are likely to be short lived affairs that will not persist to the extent where really hot weather can build up.

The transition of the upper winds from three-wave to four-wave normally occurs in late April, this is likely to be the time when high-pressure (caused by an upper ridge crossing Britain) will bring a fine warm spell to the South (though clear nights will be cold with frost likely to occur). With the upper ridge retreating westwards after this fine spell and the new (extra) trough ridge pattern inserting into the weakened upper Westerlies over Europe- Russia, this is the time when bitter Arctic winds are likely to sweep the country.

Another factor that gives me confidence in making this prediction is that winter this year (certainly the latter part of it) is not too dissimilar to late January and February last year: Admittedly there was a more decent cold spell but this year- cold waters in the NW Atlantic, reduced pack-ice in the Eurasian Arctic and slightly warmer than usual waters around the north and east of Britain bear a striking resemblance to last February. Last spring was windy in March, there was a spell of warm sunny weather in April, a nasty late-April cold snap bringing the lowest temperatures (certainly to the North Pennines) for so late in the year seen for thirty years (one man living not far from me had the entire contents of his pollytunnel killed off)- and May was cold and wet. Only this year I am more confident March will be colder than normal because the cold waters of the North Atlantic are even colder over a wider area!          

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Posted
  • Location: Irlam
  • Location: Irlam

Iapennell, what do you make of that the 5 strongest El Niños since 1950 were all followed by a below average April containing a notable wintry episode? Even the El Niño of 1918-19 which is believed to have been strong was followed by a below average April and a notable late season snow event.

Edited by Weather-history
.
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Posted
  • Location: Alston, Cumbria
  • Weather Preferences: Proper Seasons,lots of frost and snow October to April, hot summers!
  • Location: Alston, Cumbria
6 hours ago, Norway Nut said:

..... and we are still in active phase of the current Sunspot Cycle (Schwabe Cycle number 24, I do believe).

Ian,

Can you explain the phrase " active phase" in the above please?

Yes, we are in Cycle number 24 and heading towards a solar minimum in 2019.

Cheers

When the annual sunspot total falls below 70 we will have come out of the current active phase of Schwabe Cycle 24. That will mean weaker higher-latitude Westerlies because the quieter Sun will direct less solar storms with large masses of plasma interacting with the Earth's magnetic field (such events have been associated with increases in intensities of depressions in higher latitudes which means that the interaction of solar particles with the Earth's magnetic field leads to a small increase in the westerly momentum delivered to the atmosphere).  I believe the sunspot activity has passed its peak and will enter a quiet phase (as per the above definition) at some point early next year.

However the only significant small influences on the global circulation when the Sun goes quiet will be the tidal influences of the moon and Sun on the Earth which (through trying to retard the atmosphere on our planet- a bit like marine tidal friction) leads to a small loss of westerly momentum from the Earth-atmosphere system. This effect is undoubtedly greater near the Equator where the Earth rotates fastest and it must account for some of the variation of the QBO in the Equatorial stratosphere, it is well known these winds then impact on the rest of the global circulation and the influence is not negligible.   Weaker higher-latitude westerlies mean colder winters for Britain and much of Europe as blocking patterns in high latitudes have more chance of gaining a foothold and bringing frigid air from the Arctic or northern Russia. 

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Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl

A good read and logical, any westerly/northwesterly airstream would deliver colder than normal conditions during Spring thanks to SST'S reaching a very low point. We saw a very similar set up in much of 2015 until November when it all flipped, an omnipresent trough anchored to our NW which kept temps very much average at best with some colder episodes - late July being a case in point. Your suggestion the trough will align itself more to the east this time around would see the UK on the cold side, so yes the outcome would be a very disappointing Spring, indeed temps not much warmer than now... oh dear!!!

I have a feeling given how mild the last 3 months have been, there will be a cooling trend from now on.. hope I'm wrong.

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Posted
  • Location: Alston, Cumbria
  • Weather Preferences: Proper Seasons,lots of frost and snow October to April, hot summers!
  • Location: Alston, Cumbria

Some of the springs we used to have in the North Pennines in the 1970s and 1980s were really cold: Cold winds and rain at times interspersed with some savage northerlies bringing snow (so-called lambing storms when they occurred in April and threatened little lambs with hypothermia or worse- asphyxiation under deep snow-drifts!) and when skies cleared following these northerlies temperatures would regularly drop to -5C or colder (even in late April); however May used to make up for lost time with high-pressure over Scandinavia delivering temperatures above 20C (though clear nights even then would often drop to freezing).  Those are the springs with interesting extremes that I enjoyed in my teens but the warmth in May disguised the severe cold of march/April by tempering the averages- even so seasons with mean temperatures below 4C were not uncommon!

I'm not suggesting it will get this cold in Spring 2015 but there will be no long warm sunny spells in May- definitely not in the North! A warm sunny May these years is now something of an oxymoron around these parts (we have not had one for eight years).

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Posted
  • Location: Drayton, Portsmouth
  • Location: Drayton, Portsmouth

Oh Ian, I am so disappointed to hear this because I love a warm spring, and this sounds more like an endless February!! You have been more accurate than any other forecaster on here in recent years, so, where's that passport renewal form, and where's the foreign holiday brochure??

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Posted
  • Location: Cleeve, North Somerset
  • Weather Preferences: Continental winters & summers.
  • Location: Cleeve, North Somerset

Oh boy, if it transpires as such we will basically have had 6 months of the same temperatures since mid October - how depressing. How typical that the southwesterly winds would have been most prevalent at the worst point in the year; how different it would have been if the northwesterlies/northerlies were in winter and southwesterlies in spring!

Nevertheless, great description and explanation Ian. Fingers crossed that if it's going to be a cold spring, that there's plenty of convective weather about. More cold greyness would finish a lot of us off!

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Posted
  • Location: Bude
  • Weather Preferences: Extreme weather...heavy snow and heat waves
  • Location: Bude

I'm looking forward to the day Ian forecasts a winter of abundant  GL highs , cold and snow for the UK:D

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Posted
  • Location: Runcorn, Cheshire
  • Weather Preferences: Snowy winters, hot, sunny springs and summers.
  • Location: Runcorn, Cheshire

"May 2016 is certain to be wet and chilly"

Ah. So you write for the express. Can I borrow your crystal ball? I'd like to check the lottery numbers whilst I'm forecasting 15 weeks ahead. 

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Posted
  • Location: Bude
  • Weather Preferences: Extreme weather...heavy snow and heat waves
  • Location: Bude
22 minutes ago, Backtrack said:

"May 2016 is certain to be wet and chilly"

Ah. So you write for the express. Can I borrow your crystal ball? I'd like to check the lottery numbers whilst I'm forecasting 15 weeks ahead. 

Frustrating may it seem, but Ian has been closer to the mark and (impressively  accurate )with his forecasts than anyone else recently and backs it with impressive knowledge and understanding of the  certain drivers at play. I have, at times been disappointed in what I'm reading purely because I want the opposite to happen, but I will always believe in what he forecasts before anyone else's long term predictions on Netweather or any other website.

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Posted
  • Location: Exile from Argyll
  • Location: Exile from Argyll
3 minutes ago, John Badrick said:

Frustrating may it seem, but Ian has been closer to the mark and (impressively  accurate )with his forecasts than anyone else recently and backs it with impressive knowledge and understanding of the  certain drivers at play. I have, at times been disappointed in what I'm reading purely because I want the opposite to happen, but I will always believe in what he forecasts before anyone else's long term predictions on Netweather or any other website.

"May 2016 is certain to be wet and chilly" ....

.... is a very definitive statement: one that reputations are lost or won on. Personally, I think it is best to keep things vague as we've already seen the repercussions from PR disasters like the UKMO BBQ summer. Even our own GP was a little rash with his torpedo statement.

 

 

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Posted
  • Location: Carvoeiro, The Algarve
  • Location: Carvoeiro, The Algarve
13 minutes ago, John Badrick said:

Frustrating may it seem, but Ian has been closer to the mark and (impressively  accurate )with his forecasts than anyone else recently and backs it with impressive knowledge and understanding of the  certain drivers at play. I have, at times been disappointed in what I'm reading purely because I want the opposite to happen, but I will always believe in what he forecasts before anyone else's long term predictions on Netweather or any other website.

Agreed.

Ian's been pretty accurate last couple of winters (incl this winter), although some said he released this Winter's forecast a little late he's still been proven correct so far.

The second half of Winter cold predicted by some has not turned up and at the moment doesn't look like it will (certainly not down here imby)

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Posted
  • Location: Newton in Bowland
  • Location: Newton in Bowland
10 hours ago, Bristle boy said:

Agreed.

Ian's been pretty accurate last couple of winters (incl this winter), although some said he released this Winter's forecast a little late he's still been proven correct so far.

The second half of Winter cold predicted by some has not turned up and at the moment doesn't look like it will (certainly not down here imby)

Indeed he has been and if any potential businesses are looking for a reliable LRF then they should be banging Ian's door down and offering him a contract:D

What really stands a out is the fabled SSW which was touted by many individuals/organisations to occur either mid January or February, the exception being Ian who gave his reason as to why he didn't expect one. The rest is history and from here on there's only one chaps forecasts I'll be taking on board in future.

Edited by Hocus Pocus
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