Now here is a theory and it might be (and probably is) complete codswallop but here goes.



I believe in winters we are going to see less of the PV influencing the weather

The PV exists because it sits above a pool of very cold air which is sinking, think of taking the plug out of the bath and the water going down the hole, it creates a whirlpool and the PV is basically an atmospheric version of that.

Now add to the mix that the polar regions due to Climate Change are around 7-8c above average this year, as is Greenland (When cold this is why the PV often sits over Greenland), so there is less forcing or downwelling of air over the pole so less force creating the whirlpool. Hence we have a weak and disorganised PV. I believe this will become a feature of winter going forward because of said climate change. The Pole heats faster basically because there is no land mass, just ocean. The reason for the PV shifting toward Greenland over the past 2 decades, is because of this as Greenland was the nearest landmass for the cold air to pool over.



Now the bad news for us is that High pressure likes cold pools and when the PV is disorganised this allows the cold air to fall into the mid latitudes, and where there is a landmass it will cool more and more, and produce a high pressure cells. So the high pressure over Europe/Siberia is displaced south as the cold air is leaking further south due to lack of PV. The bad news for us is that this would mean that we would have a semi permanent high over central Europe in winter, with strong temperature contrast between land and sea (remember the seas are warming), low pressures will dominate the Atlantic and Pacific basins.

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I think we can all agree there is very good agreement at southwesterly or westerly winds in the run up and probably over the xmas Period.

Charts are now consistently showing some intense features clipping, hitting, or scurrying over the UK. It looks very wet. over 100mm of rainfall for the 2 week period of GFS.... like i said before, this has a very 2014 look about it

Very unsettled with little chance of frost

Slightest chances of breaking out to a colder regime are possible... but realistically this seems no different to any other year in the UK...

If there was a serious chance of maybe something colder, we would have seen some evolutions to that idea... but theres literally been nothing for days now

I would love to be wrong...

 

 

I think at the moment all hopes hinge on this maybe?

 

Xmas Day is 15 days away , I'd wait and see what the ENS say first , I'm certainly not in the agreement club 

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Control could give easterly for Xmas day

Now here is a theory and it might be (and probably is) complete codswallop but here goes.



I believe in winters we are going to see less of the PV influencing the weather

The PV exists because it sits above a pool of very cold air which is sinking, think of taking the plug out of the bath and the water going down the hole, it creates a whirlpool and the PV is basically an atmospheric version of that.

Now add to the mix that the polar regions due to Climate Change are around 7-8c above average this year, as is Greenland (When cold this is why the PV often sits over Greenland), so there is less forcing or downwelling of air over the pole so less force creating the whirlpool. Hence we have a weak and disorganised PV. I believe this will become a feature of winter going forward because of said climate change. The Pole heats faster basically because there is no land mass, just ocean. The reason for the PV shifting toward Greenland over the past 2 decades, is because of this as Greenland was the nearest landmass for the cold air to pool over.



Now the bad news for us is that High pressure likes cold pools and when the PV is disorganised this allows the cold air to fall into the mid latitudes, and where there is a landmass it will cool more and more, and produce a high pressure cells. So the high pressure over Europe/Siberia is displaced south as the cold air is leaking further south due to lack of PV. The bad news for us is that this would mean that we would have a semi permanent high over central Europe in winter, with strong temperature contrast between land and sea (remember the seas are warming), low pressures will dominate the Atlantic and Pacific basins.

 

 

Interesting post, and I can't fault the depressing logic (although I am just a keen amateur, very much at the lower end of meteorological knowledge amongst keen amateurs)

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P13 for Xmas
www.wetterzentrale.de/maps/GFSP13EU06_366_2.png

There are some absolutely fab runs in the 06z gfs run out in FI. The ensemble mean dipped further, better than 0z. Wait for 12z to reverse it again!!
Martin

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Definitely trending towards colder for Xmas week, hopefully that continues

I think we can all agree there is very good agreement at southwesterly or westerly winds in the run up and probably over the xmas Period.

That's definitely not a call I am prepared to make at this stage. It could well be correct but it is still far too early to be confident.

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On the subject of temperatures in the Northern Hemisphere I will make the following very simple observations:

1) The evidence I've seen suggests the Azores / Bores / Euro HP belt has strengthened in the last 70 years

2) We are having month after month of above CET in the UK. The frequency of colder months has decreased

3) Arctic ice levels more often than not are below the mean both when measured by extent and thickness

4) The NH appears to be warmer at most levels in the troposphere than it was several decades ago

Now I couldn't give a monkey's whether you ascribe those changes to the magic tooth fairy or global warming. However, to deny them is utterly crazy.

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On the subject of temperatures in the Northern Hemisphere I will make the following very simple observations:

1) The evidence I've seen suggests the Azores / Bores / Euro HP belt has strengthened in the last 70 years

2) We are having month after month of above CET in the UK. The frequency of colder months has decreased

3) Arctic ice levels more often than not are below the mean both when measured by extent and thickness

4) The NH appears to be warmer at most levels in the troposphere than it was several decades ago

Now I couldn't give a monkey's whether you ascribe those changes to the magic tooth fairy or global warming. However, to deny them is utterly crazy.

 

I'll add that in terms of impact for the UK, it seems over the past 20 years that...

1) Springs are getting more volatile (this last decade we've had both extreme cold and extreme warm spells)

2) Augusts have got more rubbish

3) Octobers and Novembers have got warmer

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Now here is a theory and it might be (and probably is) complete codswallop but here goes.



I believe in winters we are going to see less of the PV influencing the weather

The PV exists because it sits above a pool of very cold air which is sinking, think of taking the plug out of the bath and the water going down the hole, it creates a whirlpool and the PV is basically an atmospheric version of that.

Now add to the mix that the polar regions due to Climate Change are around 7-8c above average this year, as is Greenland (When cold this is why the PV often sits over Greenland), so there is less forcing or downwelling of air over the pole so less force creating the whirlpool. Hence we have a weak and disorganised PV. I believe this will become a feature of winter going forward because of said climate change. The Pole heats faster basically because there is no land mass, just ocean. The reason for the PV shifting toward Greenland over the past 2 decades, is because of this as Greenland was the nearest landmass for the cold air to pool over.



Now the bad news for us is that High pressure likes cold pools and when the PV is disorganised this allows the cold air to fall into the mid latitudes, and where there is a landmass it will cool more and more, and produce a high pressure cells. So the high pressure over Europe/Siberia is displaced south as the cold air is leaking further south due to lack of PV. The bad news for us is that this would mean that we would have a semi permanent high over central Europe in winter, with strong temperature contrast between land and sea (remember the seas are warming), low pressures will dominate the Atlantic and Pacific basins.

 

The jet streams (the polar jet particularly) is fundamentally caused by the difference in temperature between the Poles and the Equator. Rapid warming at the Poles compared to the Equator would weaken the jetstream? 

Definitely trending towards colder for Xmas week, hopefully that continues

Agreed , fingers crossed 

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The jet streams (the polar jet particularly) is fundamentally caused by the difference in temperature between the Poles and the Equator. Rapid warming at the Poles compared to the Equator would weaken the jetstream? 

Indeed which is what we have seen over the last couple of years, this precipitates meanderings and stuck patterns, which perpetuate cold pools and heat in the oceans.

Just look at this year, how often have we seen a raging West to East jet this year. Hardly at all.

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The GEFS mean has been steadily dropping at the end of the run for a day or two now, mean 850mb temps now down to -3C for London by the end and a 15% chance of snow or thereabouts. The op run was very much on the mild side of the pack.

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I'll add that in terms of impact for the UK, it seems over the past 20 years that...

1) Springs are getting more volatile (this last decade we've had both extreme cold and extreme warm spells)

2) Augusts have got more rubbish

3) Octobers and Novembers have got warmer

 

Rubbish meaning horribly hot for point 2?

Last August was defined by another unbearable heatwave.

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One of the biggest changes in our climate is how commonplace uncomfortable heat is down here in summer. We run the gauntlet of oppressive conditions June through September seemingly every year.

Not a good trend.

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One of the biggest changes in our climate is how commonplace uncomfortable heat is down here in summer. We run the gauntlet of oppressive conditions June through September seemingly every year.

Not a good trend.

Yes, we are looking at getting a form of Air Con installed down here, as this year was the last straw.

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Here's a comparison between 1963 and 2019 at the 850hPa level. I used a 2 deg grid resolution with 24 hour timesteps. (I could run at 6 hours with a 1 deg timescale but the script would take about 60 mins per year rather than 15 mins.

Lat: 40 to 90
Lon: 0 to 360

 

1963
-10C or lower | -5C to -9C | -4C to 0C
660637          |291005      |321637

2019
-10C or lower | -5C to -9C | -4C to 0C
573608          |294614      |334404

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Yes, we are looking at getting a form of Air Con installed down here, as this year was the last straw.

 

I have put a bed in the cabin in the garden - next best thing to aircon. As you imply, it is unbearable and impossible to sleep without some form of countermeasures. Exhausting. 

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Rubbish meaning horribly hot for point 2?

Last August was defined by another unbearable heatwave.

 

This August was the best since 2003, with half the month under warm to hot weather and a fair bit of sun. But:

1) I did state that I was talking over the past 20 years. Most Augusts this century have overall been below average, and we've struggled for great August months (in the same league as 2003), whereas we've had several very nice  June's and July's

2) I'm talking the whole of the UK (even in the fantastic summer of 2018, by early August the very settled, sunny and warm weather had been replaced by more unsettled conditions across the north-western half of the UK at least). The SE has perhaps not experienced as poor August weather as the rest of us.

3) Away from the SE this August, there were some hot days for sure, but the focus of the heat and settled weather was in the SE and S.

4) in the second half of the month, we had both Storm Ellen and Storm Francis, which brought high winds, much lower temps and widespread heavy and prolonged rain to many parts.

 

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