Model Output Discussion 29th December - Into mid-Winter.

[Man With Beard]

Tonight's EC monthly will not silence the Feb 1991 brigade:

of course most runs at that range this winter have drastically underestimated the amount of blue to our north, so not a chart to go crazy about just yet.

[Gael_Force]

1 hour ago, Seasonality said:

There is a term for this period that I can't remember. It refers to the first half February often being the coldest part of winter "the x minimum." Just can't remember what the x is, I keep thinking Maunder Minimum but I know that is something completely different. Can anyone help?

It's called the 'series minimum' for coldest part of winter in mid february. I'm assuming the series refers to the CET. 

Edited January 16, 2017 by Gael_Force

[Guest]

Please note that Judah Cohen’s latest update has been delayed by 24 hours and will be published on Tuesday evening. I will provide my usual coverage then.

CENTRAL ENGLAND TEMPERATURES (CET):

I noticed the conversation on the MOD earlier this evening regarding the CET records. I see that @karlos1983 asked what were the readings based on and I saw the “short” correct answer in respect of the triangular area used for determining the mean. This data set was established by the famous climatologist Gordon Manley and it took him over 30 years to compile the temperature records taken from his carefully chosen “representative” sites within the “triangle” (London, Bristol and Lancashire). It was the longest temperature record set anywhere in the world and goes back to 1659, so his choice was limited by the much smaller number of observation sites in those early days. He had to overcome the variability of specific site conditions and made allowances for the changes in recording temperatures such as exposed “north wall” thermometers at Greenwich and Kew, then the changes to the Glaisher white board stands and finally to the standardised Stevenson's screens. His work was first published in 1953.

He wrote two papers on this in the Royal Meterological Society Quarterly Journals in 1953 and 1974. They are fascinating reading and will tell you everything that you need to know about CETs – here are the links to download the pdf documents:

http://www.rmets.org/sites/default/files/qj53manley.pdf

http://www.rmets.org.uk/sites/default/files/qj74manley.pdf

His work is maintained today at the Met Office’s Hadley Centre. They made certain adjustments which were criticised by meteorologist, Philip Eden. He constructed his own record set which he says are much more closely related to Manley’s criteria and maintain a far better consistency. Both data sets were available for comparison.

Many readers will be familiar with Gordon Manley’s excellent book: “Climate and the British Scene” first published in 1952. This is one of the most enjoyable “Weather” books that I have ever read and I highly recommend it to everyone who is learning the subject as well as more seasoned posters. It has had several reprints and I think it is still available (probably on Amazon or eBay or from other leading book sellers).

 

Edited January 17, 2017 by Guest

[Ali1977]

Things could be looking up again - PV looking weak again towards the end of the month on many ENS, plenty of colder options sneaking back in too - few examples below.

[northwestsnow]

 

 

 

10pha today

 

 

10pha 31 January

 

GFS still suggesting a bit of a change up in the strat over the coming 10 days or so, will be intersting to see how this pans out.

 

 

[jvenge]

EPS 46 mean is mild for the foreseeable. The only good thing to say about it, for those wanting cold, is that it's signal doesn't look so strong after day 15 or so.

I'd be really surprised if ALL of Europe manages to stay under warmer air than usual for so long. 

[feb1991blizzard]

5 minutes ago, northwestsnow said:

 

 

 

10pha today

 

 

10pha 31 January

 

GFS still suggesting a bit of a change up in the strat over the coming 10 days or so, will be intersting to see how this pans out.

 

 

A big zonal wind reversal right at the very top showing up now, best run so far.

[The Beast From The East]

Good morning, so reading all the post on hear it now looks like we're hoping for end of Jan or in to Feb for maybe are next chance to hopefully get something wintery.

Does anyone have a guid or a chart showing how the average temps should be during say from December through to March ?  We often see the temps we should expect from Spring through till say October and as you would expect August is the peak in temps. I wonder when the peak is for the possible coldest temps we should expect. 

Cheers.

[ArHu3]

2 minutes ago, Unleash the Beast said:

Good morning, so reading all the post on hear it now looks like we're hoping for end of Jan or in to Feb for maybe are next chance to hopefully get something wintery.

Does anyone have a guid or a chart showing how the average temps should be during say from December through to March ?  We often see the temps we should expect from Spring through till say October and as you would expect August is the peak in temps. I wonder when the peak is for the possible coldest temps we should expect. 

Cheers.

For the netherlands 2nd week of january to 2nd week of february is generally the coldest period, I think it's probably not to different on the other side of the pond

[IDO]

The London Ens sum up the chances for snow in the next 16 days, 5% at best. A week of below average temps then the possibility of much milder temps for the next 5-6 days as the zonal spell takes hold. The D10 mean is self-explanatory:

 GEM D10

Where the boundary between higher and lower pressure meets being the main variation on the GEFS. The GEM op is 100% behind the GEFS mean. 

So the rest of Jan is average UK winter fayre, cold and dry the further SE you are this week then wet and windy the further NW you are next week, with a period of uppers +8c above average at times.

Late Jan should see the NPO index move from positive slowly to negative so potential for pattern change if that is correct.

ECM 0z has really struggled at D10 of late and i would ignore their D9 & D10 charts as the model is clearly unreliable after D8. Looking at the 0z verification; at D8 is is an easy winner, but by D10 only CFS is worse, and it has verification of 0.1 on a couple of occasions. Of course the models are experiencing uncertainty, but ECM should still be top dog. However it has been apparent for a while when these setups are predicted it loses the plot more than the competition:

The GEFS towards D16 are showing more amplification towards the Pacific as the NPO would suggest, so maybe some interest early Feb, whilst we await the possible SSW.

 

[winterof79]

GFS going it's own way with its modelling over Canada and Northern States.Interesting latter stages from ECM and GEM with more forcing over the pond.We will have a period of Atlantic driven crud to go through for sure as is the norm for our Island but if we can get a week of proper winter I'm sure it will be worth it

 

 

 

Edited January 17, 2017 by winterof79

[TEITS]

Looking at this mornings output and a trend I have noticed has gathered pace. The calls of a return to unsettled, zonal spell of weather are beginning to look rather dodgy.

Note on the ECM low pressure in the Atlantic is constantly being modelled to be further NW from the UK and as a result high pressure remains in control. Now at the moment this isn't a good thing for cold lovers because mild SW,lys are being suggested. However this is a new developing trend and I shall await to see what happens over the next few runs.

[winterof79]

2 hours ago, northwestsnow said:

 

 

 

10pha today

 

 

10pha 31 January

 

GFS still suggesting a bit of a change up in the strat over the coming 10 days or so, will be intersting to see how this pans out.

 

 

For once it is getting nearer and stronger too

[Ali1977]

20 minutes ago, winterof79 said:

For once it is getting nearer and stronger too

Good point, hopefully this gathers pace as getting one late Jan would be much better than later into Feb - March 13 worked out well with a later SSW but that was a one off.  

Could the EC32 be pick up effects from a SSW, this may not be Northern blocking though  !

Edited January 17, 2017 by Ali1977

[Argyle1980]

This mornings ECM at 240 hinting of the high over Europe rising to our NE and maybe that low in the Atlantic sliding down to the med.

all trends worth watching  and with SSW coming into the frame nothing can be ruled out.

[Troubleatmill]

32 minutes ago, TEITS said:

Looking at this mornings output and a trend I have noticed has gathered pace. The calls of a return to unsettled, zonal spell of weather are beginning to look rather dodgy.

Note on the ECM low pressure in the Atlantic is constantly being modelled to be further NW from the UK and as a result high pressure remains in control. Now at the moment this isn't a good thing for cold lovers because mild SW,lys are being suggested. However this is a new developing trend and I shall await to see what happens over the next few runs.

Not sure I see high pressure in control on that chart TEITS? Central Europe for sure, hope you have spotted something though.

[Seasonality]

Just now, Nicholas B said:

Not sure I see high pressure in control on that chart TEITS? Central Europe for sure, hope you have spotted something though.

High pressure clearly in control, a tongue of blocking extending over UK and through to Scandi. Ff anything, more easterly parts of Central Europe (ie Poland, Czech Republic, Slovakia, Hungary) have somewhat higher pressure but lower 850s. High pressure still in control though. I prefer meteociel charts as I personally find them more clear. Here pressure and thicknesses without 850s for clarity. Completely different from yesterday's 12z. Note the progression from 216 to 240. Pressure lowering over the med, Atlantic trough pushing east and high pressure being pushed north east.

[Seasonality]

My little battle between ECM and GFS for temperatures in Poland is now going the way of the GFS! After days of faffing around and predicting milder temperatures the ECM now agrees with the GFS for this Friday and the weekend with -double digit minimum on Friday morning and it has pushed the warm up to above freezing back to 25 January. Forecast from yr.no which uses ECM data.

 

 

[Troubleatmill]

28 minutes ago, Seasonality said:

High pressure clearly in control, a tongue of blocking extending over UK and through to Scandi. Ff anything, more easterly parts of Central Europe (ie Poland, Czech Republic, Slovakia, Hungary) have somewhat higher pressure but lower 850s. High pressure still in control though. I prefer meteociel charts as I personally find them more clear. Here pressure and thicknesses without 850s for clarity. Completely different from yesterday's 12z. Note the progression from 216 to 240. Pressure lowering over the med, Atlantic trough pushing east and high pressure being pushed north east.

No still don't see high pressure in control, depends where you live a I guess, if you are the midlands north that has breezy, grey laden sky with rain written all over it, not my idea of high pressure in control.

Edited January 17, 2017 by Nicholas B

[MAF]

2 hours ago, Unleash the Beast said:

Good morning, so reading all the post on hear it now looks like we're hoping for end of Jan or in to Feb for maybe are next chance to hopefully get something wintery.

Does anyone have a guid or a chart showing how the average temps should be during say from December through to March ?  We often see the temps we should expect from Spring through till say October and as you would expect August is the peak in temps. I wonder when the peak is for the possible coldest temps we should expect. 

Cheers.

this is from the Met O for my area, if you put your area in it will show the temps for the year

http://www.metoffice.gov.uk/public/weather/climate/u10hcktps#averagesTable

[Seasonality]

Just now, Nicholas B said:

No still don't see high pressure in control, depends where you live a I guess, if you are the midlands north that has grey laden sky with rain written all over it, not my idea of high pressure in control

So you're making a comment on what you believe high pressure in control looks like in your personal opinion rather than what the charts show? Not having a go at you but for sake of clarity to make sense of what you are seeing because both of those charts show high pressure controlling the weather over the bulk of Europe. High pressure can be grey and drizzly too, not just bright and sunny. 

[Singularity]

During large MJO events I believe there is a tendency for models and their ensembles to implement the changes quickly and cleanly, with the resultant setup difficult to break down within even a whole week, but then as the times draw nearer, complications arise, the pattern response to the MJO becomes less clean, and further changes in background forcing seem more able to take down the new pattern in short order.

With ECM seeing the MJO propagating east out of phase 8/1 while remaining amplified, it's increasingly seeing alternatives to a positively tilted mid-Atlantic trough. Indeed with further amplification from upstream the idea of the trough stalling, becoming negatively tilted and disrupting with a secondary low sliding toward Europe seems very logical. Funny how this may mean the theme of the winter so far - HP dominance via ridges extending out of Europe - gets to show its hand yet again.

GFS still only has a gradually decaying MJO in 8/1 so there's less impetus to move away from the positively tilted mid-Atlantic trough, but even here we see some signs of changes beyond around 10 days range.

 

So many times we see assumed long-term pattern changes cut short or even derailed. It happens (too) often with changes to cold patterns and certainly occurs for changes to mild patterns too. Another reason not to 'face value' the model output

[russell k]

1 hour ago, IDO said:

The London Ens sum up the chances for snow in the next 16 days, 5% at best. A week of below average temps then the possibility of much milder temps for the next 5-6 days as the zonal spell takes hold. The D10 mean is self-explanatory:

 GEM D10

Where the boundary between higher and lower pressure meets being the main variation on the GEFS. The GEM op is 100% behind the GEFS mean. 

So the rest of Jan is average UK winter fayre, cold and dry the further SE you are this week then wet and windy the further NW you are next week, with a period of uppers +8c above average at times.

Late Jan should see the NPO index move from positive slowly to negative so potential for pattern change if that is correct.

ECM 0z has really struggled at D10 of late and i would ignore their D9 & D10 charts as the model is clearly unreliable after D8. Looking at the 0z verification; at D8 is is an easy winner, but by D10 only CFS is worse, and it has verification of 0.1 on a couple of occasions. Of course the models are experiencing uncertainty, but ECM should still be top dog. However it has been apparent for a while when these setups are predicted it loses the plot more than the competition:

The GEFS towards D16 are showing more amplification towards the Pacific as the NPO would suggest, so maybe some interest early Feb, whilst we await the possible SSW.

 

Any idea when the ENS update on NW ? still showing 06 from yesterday,,,thanks

[Troubleatmill]

13 minutes ago, Seasonality said:

So you're making a comment on what you believe high pressure in control looks like in your personal opinion rather than what the charts show? Not having a go at you but for sake of clarity to make sense of what you are seeing because both of those charts show high pressure controlling the weather over the bulk of Europe. High pressure can be grey and drizzly too, not just bright and sunny. 

Nope I believe it is what the chart shows for the majority of the uk, yes high pressure is in control of the vast of Europe but we are talking about the UK. High pressure is clearly in control as we speak and it is grey and drizzly in my location so I understand what you say, but if you watched the BBC forecast for the day shown (if it turned out that way) they would not be saying high pressure in control of the UK weather. We will have to agree to disagree  

Edited January 17, 2017 by Nicholas B

[Seasonality]

Just to emphasise the differences between the two most recent ECM runs.