BadgeIsBack

It seems there is snow in parts of the UK. The UK is really getting cold why?

Lots of confusing advice. On the one hand Co2 levels are increasing and people have long been obsessed with them. Arctic sea ice is melting.

On the other hand, we've had a spate of cold ones. (Winters, Not beer! Wake up!)

I've had a handle on the fact it seems that the salinity changes in the sea can effect the subterrean currents that bring warmer water to NW Europe...this is long term - but it also seems that the differential in temps between the UK and Arctic is reducing and allowing the Uk to get cooler weather...

...hot off the press..my weather forecast guru (not climate change - that is harder) tells me that there is oscillation of some sort in the Arctic which periodically (seasonally) brings colder winter to the north..only recently is this incorporated in models.

cheers!

verystormy

Its not difficult The UK has always had a risk of late snow - same as it has always had a chance of later summer - known as the indian summer. It is not evidence of climatic change.

BadgeIsBack

I agree about climate change, it's hard to know, but my guru tells me that these seasonal changes can be brought about by seasonal oscillations....I may not have the terminology right, it's also a function of high level winds...

and he and colleagues can predict them...or the effects....

GarryP

http://www.guardian.co.uk/environmen...c-sea-ice-loss

Basically the Arctic has been getting much warmer, with climate change, than the general rise in temp. That means its very shortly going to be sea ice free in summer. It also means that the heat gradient between the equator and the poles is less, and its that gradient that powers the big scale airflow in the atmosphere. Via fluid dynamics, the atmosphere breaks into 'cells' with this flow, with the jet streams formed between these cells and the weather systems constrained by these cells and the boundary jet streams. Since the heat gradient is less, the cells change shape, and with them the jet streams location, and the weather. The UK gets hit with european type winters, instead of what its used to.

Amazulu

It happens like this sometimes. Nothing to do with climate change

carolinephillips

It is the oscillation which for some reason has kinked, dragging the cooler Arctic air down over the UK instead of where it normally sits, over Scandinavia. This can happed sporadically whatever the climate.

My dad was a meteorologist and spent many happy hours explaining clouds, jet stream, gulf stream, and weather patterns to me. He used to bring home the satellite pictures, and for join the dots (in the days before computers) he'd bring home maps with the barometric pressures on them and then we'd join them up to draw the isobars!

BadgeIsBack

I'm not sure why people are focusing on climate change when my final point and last post talked about the ability of forecasters to forecast these spikes and seasonal weather changes...not of climate....I only mentioned climate to introduce the topic, then channeled in to these local events.....to debunk climate change ...I am in agreement with you.

BadgeIsBack

Yes, this is weather, seasonal stuff, and which can therefore be forecast to an extent (seasonal forecasts) not climate...and can effect why it can get cold...I can't be clear whether we are talking about exactly the same effect...(as I am not 100pc on the terminology..)

My friend tells me though that now they are going to introduce this into the computer models in a away they have not done previously.
The util companies like to use the forecast to work out energy requirements...

GarryP

The reason why I was quickly trying to answer your question with reference to climate change is that the reason for the shift of the jet stream is thought to be because of climate change. That ties in with caroline's reference to 'kinked' and arctic air.

Check out this diagram:




If the polar jet stream moves south, the the UK gets cold northern winds. The position of the polar jet is chaotic, but its tied to the gradient of that temp gradient between pole and equator (eg the top red line). The theory is that the dramatic temp increase in the arctic cuts the gradient and is directly responsible for the 'spike' referenced - and the general shifting of the jet streams, Rossby waves, and 'joining' of the two streams on a more regular basis.

http://www.twnside.org.sg/title2/res...70/cover13.htm

Grayling

Late snow is nothing new. I remember heavy snow one day in May in the late 70's when it caused problems on the opening day of the the trout fishing season at Rutland water.

A county cricket match was stopped because of heavy snow at Buxton in June 1975

Not really that unusual

BadgeIsBack

Glad to be informed Gary, and it seems that my talk about general climate change, by way of introduction to seasonal weather was more telling than I had realised after all... The problem I have now is that I am not sure if the phenemenon my friend talked about is this same effect, because he seemed to link it to a general change that was more pronounced in some years and not other - a sort of wobble (and! I don't think he was talking about those wobbles in the earth's spin either..)

Seeing as you've got so technical, I will actually confirm with him whether this effect is the one he was talking about.

Regardless, plugging it into the model gives us a more accurate seasonal forecast it would seem - and he has been tasked with aspects of the collaboration.

I experienced snow in April 2008 (first night back in the UK) and was moderately surprised. It has been a long time (in my living memory which may be flawed of course) since I recall snow so late.

What I think this reminds me is that the UK is in latitudes where, found on other continents, brings far colder weather...!

commonwealth

the world's climate is ****ed up. in Sydney it's almost 'winter' but the beaches are warm enough - 20 degrees seawater during noontime!

BadgeIsBack

But as my friend says, we had a win with CFCs! Remember those. We actually won there.

GarryP

Think of it like this. Climate change means that hurricanes get more frequent, and stronger. However they don't predict when or where they will occur - its statistics not specifics.

It's the same as the effect on the jet stream and the cells. We know that the reduced temp gradient will shift them, but the full complexity only comes from some complex models - in particular the hydrodynamics, the waves, and the speed. Whilst the basics are simple physics (5-6C arctic rise = less gradient) the specifics are much more complex. For instance, the differential heating of the ocean and the continent in the winter seems to have some effect.

It's one of the reasons you don't want any climate change - the eventual outcome is complex/chaotic and you really don't want to f**k with it.

BadgeIsBack

Yes, that's the impression I get all along - the matters of degrees end up with disaster..

BTW, trawling back through the posts I see I missed your first technical explanation.

I find weather fascinating - what is even more so, is the way forecasters can model actually very accurately - more than we realise.
There is a lot of collaboration going on between the N and S Hemispheres.