Model output discussion - 5th December 2016 - Into Winter we go

[Rocheydub]

1 minute ago, fergieweather said:

Yup it's fine. There's every reason to have cynicism in longer-lead output currently, but equally there's scope for some optimism too (for the colder winter weather fans). 

Just hearing about your old colleague Ian, so terribly sorry for your loss. I live in Dublin, but regularly switched to BBC over the decades, to see what his thought's were in the years before (and after) the internet age. A terrific way of explaining to the masses, and a scientific knowledge never weakened from doing so. A huge loss! Hope you will oblige me by passing on the condolences of the Irish weather enthusiasts to your buddies.

As a great tribute to him, I hope that mother nature continues to battle with the wits here and beyond, by confounding us all with predictions and different results! As we say here in Ireland: Ar dheis De go raibh a anam.

 

Back to NWP, slightly more encouraging, but still not hopeful for a cold and possibly snowy festive season by the 12's and 18 outputs. 

[JBMWeatherForever]

Ian McCaskill - Legend, very sad to hear that he has passed way. He was so good to listen to and such a personality with it. I remember him giving the weekly forecast during the epic spell of early January 87 with his tales of the timber wolf etc. Remember that spell came at quite short notice, just as many Easterly's do. On this occasion though I do think it being flaged up for us.     

[Chris.R]

14 minutes ago, karlos1983 said:

Really Don't want to see mucka naked, don't want south westerlies, oh life choices are a pain sometimes ! 

 

 

  I'm still Waiting for Backtrack to eat his socks from 2010 so God knows when that's happening! I've just got this feeling that this Easterly will come off at the end of the month. I've got no science to back this up but there you go. . 

Edited December 12, 2016 by Chris.R

[Frosty.]

3 minutes ago, Rocheydub said:

Back to NWP, slightly more encouraging, but still not hopeful for a cold and possibly snowy festive season by the 12's and 18 outputs. 

It's too early to say, a lot can change in two weeks.

[feb1991blizzard]

GEFS have gone more zonal again though.

[Rocheydub]

2 minutes ago, Frosty. said:

It's too early to say, a lot can change in two weeks.

Indeed, no disputing that.

I am however discussing the latest output as I stated. This is the MOD thread, not the "I give up hope and despair" thread! :-)

[karlos1983]

5 minutes ago, feb1991blizzard said:

GEFS have gone more zonal again though.

Flicking through fl and I'm seeing a lot of not very zonal at all charts Feb? Or are you talking earlier?

i guess 50/50 ish 

Edited December 12, 2016 by karlos1983

[Rocheydub]

1 minute ago, karlos1983 said:

Flicking through fl and I'm seeing a lot of not very zonal at all charts Feb? Or are you talking earlier?

Sorry Karlos, no doubting it, there is a bigger swing through all the ensembles to a more westerly dominated regime, from mid range to FI.

[feb1991blizzard]

2 minutes ago, karlos1983 said:

Flicking through fl and I'm seeing a lot of not very zonal at all charts Feb? Or are you talking earlier?

6 or 7 out the first 10 show zonality (of sorts) only 1 or 2 show proper blocking and none with blocking to the North and a cold uppers via an Easterly at 384.

[karlos1983]

3 minutes ago, Rocheydub said:

Sorry Karlos, no doubting it, there is a bigger swing through all the ensembles to a more westerly dominated regime, from mid range to FI.

Fair enough, I didn't look in great detail. ECM ensembles don't look great tbh 

 

Edited December 12, 2016 by karlos1983

[weathermadbarnsleylad]

Interesting reading as always from everybody I might be on the wrong page but can't see much hope for cold and snow from the latest output today. It feels like it could get close then. Next time you look its gone so frustrating  but if it was so simply we wouldn't be weather mad it's a rush that never goes away and we always come back for more but eventually we will get what we all want roll on the 00z and hope That stellar run comes and stays night all

[Paul_1978]

384 this, 384 that....

Whatever's showing at 384...it ain't gonna happen. 

[feb1991blizzard]

1 minute ago, karlos1983 said:

Fair enough, I didn't look in great detail. ECM ensembles don't look great tbh 

 

Yes the ECM ens look bad in graph form, was expecting that though anyway after Matthew Hugo's comment.

[weathermadbarnsleylad]

1 minute ago, Paul_1978 said:

384 this, 384 that....

Whatever's showing at 384...it ain't gonna happen. 

Always seems that way

[feb1991blizzard]

The problem now is that the latest runs of the 2 model suites (12z EC EPS and 18z GEFS) are both poor for cold, the Glosea5 and EC46 are run off 24 hour old starting data.

[Tamara]

50 minutes ago, feb1991blizzard said:

The problem now is that the latest runs of the 2 model suites (12z EC EPS and 18z GEFS) are both poor for cold, the Glosea5 and EC46 are run off 24 hour old starting data.

This post I type will already be out of date (technically) by the time I have posted it. You will not eat, sleep, breathe. do anything outside of the virtual NWP world and live in any moment in time if, like some others on here, you wait on every single model suite seeking constant data reassurance

There is simply not a need to watch all of it, model by model, frame by frame - let alone the fact there is no time to do it.  

For my own perspective -  and taking into account the usual caveats of uncertainties and distance in time, there is enough there to reflect very well the musings of the post made earlier today. Much of that relates to the period at the furthest end of day 10 to 15 output anyway.

I'm still reflecting about Ian MacC  He was like a favourite Uncle, a real sweetie - not the precise description many would use on here, but the 6 Feb 91 forecast is as clear as a bell in my mind. Like others maybe, I can remember the whole day, where I was (at work) the arrival of those first powdery snow showers sifting along the bone dry surfaces...and then home in the evening and that classic forecast, delivered in his inimitable way

Unlike the temperature In Richmond (25C that day) lets hope it won't be a long long time before we have to wait to revisit those synoptics.

RIP

 

Edited December 13, 2016 by Tamara

[Guest]

UPDATE TO MY RECENT POST WITH LATEST DR JUDAH COHEN REPORT

Please refer to my full report (No. 3) posted on Sunday, December 11th on page 84 of this thread.

Dr Judah Cohen’s Latest Arctic Oscillation Report:

Judah Cohen’s has just published his latest AO report (late last night on December 12th). It makes for vital reading and I would sum it up as “reasonably encouraging for coldies” but we may have to wait until week 3 and week 4 to see the Siberian and West Asian deep cold to spread back into Europe. It is after 1 am and I’ve had a very long day, so I’ll only make very brief comments below but I will provide further analysis in my next full post (Winter 2016-17 Report no. 4 due on Sunday, December 18th). Here is the link to Judah's update:

http://www.aer.com/science-research/climate-weather/arctic-oscillation
 

I copy his summary below:

..."Summary

The Arctic Oscillation (AO) is currently positive and is predicted to remain positive week one and then trend negative close to neutral week two.

The current positive AO is reflective of mixed pressure/geopotential height anomalies in the Arctic but mostly positive pressure/geopotential height anomalies across the mid-latitudes of the North Atlantic sector. The North Atlantic Oscillation (NAO) is currently neutral because of positive height anomalies near Iceland and Greenland.  However, the NAO is also predicted to remain mostly positive over the next two weeks.

With the possible exception of Northern Europe, I continue to believe that variability associated with the AO does not currently best explain anticipated weather across the Northern Hemisphere (NH).  Instead recent and future variability associated with the polar vortex (PV) best explains the large-scale weather patterns across the NH continents.

The lowest geopotential heights and coldest temperatures are predicted to persist across Northwest Asia and Siberia where the stratospheric PV center has been located for much of December.

Upstream from the negative geopotential height anomalies over Northwestern Asia, positive geopotential height anomalies predicted over Europe will result in a mild pattern for much of Europe.  However, as the center of the ridging/positive geopotential height anomalies migrate north, colder air from Western Asia will start to slide west underneath the ridging across Southern Europe.

Cross polar flow around the main PV center is helping to drive Arctic air south first across Western North America and then east into Southeastern Canada and the Northeastern United States.

However, with the PV predicted to strengthen, the models are predicting a milder pattern across North America, especially in eastern North America.

East Asia tends to be colder ahead of rather than post a PV weakening event and consistent with this pattern, temperatures are predicted to be seasonable to mild in East Asia over the next two weeks.

It is my opinion that the next few weeks are critical for winter means as we transition from a weak to strong PV regime and potentially setup (or not) for a subsequent PV weakening...."

 

Here is part of his more detailed look at the “Impacts”:

“….Impacts

With a relatively quiet period in upward Wave Activity Flux (WAFz)/poleward heat flux predicted over the next two weeks, the prolonged PV weakening/sudden stratospheric warming (SSW) is predicted to conclude with the stratospheric PV returning to normal.  This includes the PV center returning to a location near the North Pole and with the lowest heights and temperatures over the Arctic basin.  How much and when the stronger PV will influence the weather across the NH in my opinion still remains an open question but something that needs to be considered strongly in trying to anticipate weather beyond the synoptic time scale (7-10 days).

In the near term the atmospheric circulation across Eurasia looks fairly stable over the next two weeks. Ridging/positive geopotential height anomalies will remain centered over Europe but slowly sliding north over time.  Downstream from the ridging, troughing/negative geopotential height anomalies stretching from Western Asia east across all of Siberia. This will favor widespread above normal temperatures for Europe with widespread below normal temperatures across Western Asia and northern Eurasia including much of Siberia.  The circulation across North America will be more transitory.  Initially a strong ridge/positive geopotential height anomalies north of Alaska will help force a deep trough/negative geopotential height anomalies and cold temperatures across much of Canada and the Northern US.  Next week, energy and negative geopotential height anomalies from Siberia will propagate eastwards across the Bering Sea towards Alaska and Western Canada.  Cold temperatures will therefore likely continue across Alaska and Western Canada.  However, with the axis of negative geopotential height anomalies shifting further west over time, favors rising geopotential heights and temperatures across the Eastern US for next week.  As I discuss below I don’t consider the prediction of milder weather a pattern reversal but rather a relaxation of the cold pattern, at least not yet.  But uncertainty is quite high.…..”  

 

Judah continues with his usual look at the near term, the next few weeks and further ahead. This part contains many maps, charts and diagrams and is far too long for me to reproduce here.

Brief Comment:

So Judah, like many other experts, is also uncertain but he feels that the mild spell in Europe (and the UK) is only likely to be a temporary “relaxation of the cold pattern”  He indicates around  2 weeks of mild weather across much of Europe which is in line with most of the models. He explains his views on and reasons for the delay in renewed cold. We will need to be patient (as always) but Judah is still optimistic for much of the Winter but a little less so than last week. Like many others, he feel that we are reaching a crucial point during the next couple of weeks. Good night!

@fergieweather I sent a full reply to you last night following your interest about the Rickmansworth frost hollow and my weather station there - you will find it in your Netweather message box.

Edited December 13, 2016 by Guest
correct typos

[Backtrack]

3 hours ago, Chris.R said:

  I'm still Waiting for Backtrack to eat his socks from 2010 so God knows when that's happening! I've just got this feeling that this Easterly will come off at the end of the month. I've got no science to back this up but there you go. . 

Mate those socks are long eaten! 

Whats happening is a standard winter pattern. The U.K. Can never seem to sustain anything for a long period of time, so the usual mild, cold, mild, cold scenario looking likely, I do think a colder spell is on the cards soon. Hopefully in time for Christmas. 

[Mucka]

 

While hardly a classic Easterly I would happily admit that would be colder than anything I expected from the East if it came off.

But I would also note it comes about by shortwave trough dropping down and moving West under the high and not undercut from the Atlantic, something I said could happen but I didn't expect the high to be far enough North for it to draw colder air over us.

Clearly it is here,at least for a short while which at least would have it feeling more seasonable  a day or two before Christmas.

Right, I'm off for a long break so early merry christmas to one and all.

Fingers crossed for some of the white stuff soon.

Edited December 13, 2016 by Mucka

[Snowman.]

Surprised you didn't mention the para Mucka, goes with the theme if sliding lows against a high to the north east.

[knocker]

Today

Not very inspiring with outbreaks of rain and drizzle in most areas as this area trundles NE during the Day. Perhaps a bit brighter behind but more sporadic rain will approach from the south west later Scotland also cloudy with some drizzle except the north which is clear with some frost this morning. Otherwise continuing quite mild particularly in the south west.

The GEFS is showing no significant changes in the long wave pattern this morning so once again it's a matter of a quick look at the day to day detail vis the det. output.

Friday sees the familiar story of the upper trough deconstruct over western Britain against the high pressure and yet another surge of the Azores HP NE over the weekend.

The high pressure then proceeds to consolidate to the east during next week with the UK remaining under it's influence except possibly the NW of Scotland where fronts from the west may just encroach. Thus all parts remaining dry with temps around average but getting cooler towards the end of the week' There is one area of interest though as it does return to an old theme. The energy in the form of the jet runs around the HP and once again a small low breaks off from the trough to the east and tracks west around the high pressure

This low continues it's journey west and by T240 there is an upper cold pool over France/southern Britain with the surface low a little further south east. All of this backs the surface flow easterly and accounts for the aforementioned drop  in temperature but still remaining dry. This seems like a very good time to stop.

Edited December 13, 2016 by knocker

[Seasonality]

A chilly xmas eve on the 00z. Poor old Father Christmas expecting the usual mild UK mush for a liitle break after he crosses the Atlantic. And for those looking for cold to the east a significant amount of really frigid ensembles appearing for Warsaw. 

 

[Seasonality]

5 hours ago, Bring Back1962-63 said:

 

Brief Comment:

So Judah, like many other experts, is also uncertain but he feels that the mild spell in Europe (and the UK) is only likely to be a temporary “relaxation of the cold pattern”  He indicates around  2 weeks of mild weather across much of Europe which is in line with most of the models. He explains his views on and reasons for the delay in renewed cold. We will need to be patient (as always) but Judah is still optimistic for much of the Winter but a little less so than last week. Like many others, he feel that we are reaching a crucial point during the next couple of weeks. Good night!

 

Just to add to your comment. In the north of central Europe and in eastern Europe there was only a little 'snap' of mild. Back to average or a touch colder at the surface now.

[Gustywind]

29 minutes ago, Seasonality said:

A chilly xmas eve on the 00z. Poor old Father Christmas expecting the usual mild UK mush for a liitle break after he crosses the Atlantic. And for those looking for cold to the east a significant amount of really frigid ensembles appearing for Warsaw. 

 

A few chilly ensemble members but the vast majority are milder than -5 850 temps, which isn't great for Warsaw, or ourselves if we want a cold easterly.

Apologies - They are 2m temps, thanks to those who flagged this.

Edited December 13, 2016 by Gustywind

[shotski]

8 minutes ago, Gustywind said:

A few chilly ensemble members but the vast majority are milder than -5 850 temps, which isn't great for Warsaw, or ourselves if we want a cold easterly.

Aren't they the 2m temps ?