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

[Nick L]

To put the radiosonde myth to bed...

http://weather.uwyo.edu/upperair/sounding.html

Check out the archives, soundings are still made on Christmas Day. And let's be honest, in the grand scheme of things, radiosonde data is TINY in comparison to the world. I fully expect this nonsense to be brought up again next Christmas, and the next, and the next. That's the last I'll say on this matter.

[TEITS]

15 minutes ago, Nick L said:

"there have been studies into it"

I'll also add that myself and several others on here actually work as forecasters, and this "lack of data" myth has zero bearing on our thoughts. In fact, I haven't heard it mentioned once in my office. It's only something that seems to have manifested itself through hearsay on forums and social media. If a butterfly flaps its wings in China, you get Chinese whispers.

So you don't believe in the chaos theory with regards to the NWP. Astonishing, back to basics for some I feel!!

[shotski]

2 minutes ago, Nick L said:

To put the radiosonde myth to bed...

http://weather.uwyo.edu/upperair/sounding.html

Check out the archives, soundings are still made on Christmas Day. And let's be honest, in the grand scheme of things, radiosonde data is TINY in comparison to the world. I fully expect this nonsense to be brought up again next Christmas, and the next, and the next. That's the last I'll say on this matter.

And maybe again for the orthodox Christmas 

[TEITS]

3 minutes ago, Nick L said:

To put the radiosonde myth to bed...

http://weather.uwyo.edu/upperair/sounding.html

Check out the archives, soundings are still made on Christmas Day. And let's be honest, in the grand scheme of things, radiosonde data is TINY in comparison to the world. I fully expect this nonsense to be brought up again next Christmas, and the next, and the next. That's the last I'll say on this matter.

Radiosonde data is tiny eh? Some disagree.

http://www.greatfallstribune.com/story/news/local/2015/04/02/weather-balloons-still-critical-forecasting/70861502/

[swilliam]

15 minutes ago, TEITS said:

How do we know it has a negligible effect. If a butterfly flapping its wings can change the outcome then surely lack of data can do the same. Also do you know the exact amount of weather balloons launched on a normal day and how many on xmas day. If you cannot answer then you cannot say Xmas model output isn't affected.

This seems to me to be very easy to prove or not. There are detailed verification statistics for all the models at different timescales. If someone would care to go back through these over the years then if there was any influence of any change in the amount of data over Christmas then this would  show up as highly correlated dip in model accuracy over 25/26/27 Dec. I am not going to do this as

• It is up to those who believe this to be true to show this - not for others to prove that there is no correlation
• I am sure the world weather organisations have already checked this and would have highlighted it if there was a dip in model accuracy over this period 

[snow mad]

33 minutes ago, TEITS said:

Run out of helium

Wasn't  that when the models were showing relentless gales over the Christmas period and now it's flipped to quite anticyclonic?

[legritter]

11 minutes ago, TEITS said:

How do we know it has a negligible effect. If a butterfly flapping its wings can change the outcome then surely lack of data can do the same. Also do you know the exact amount of weather balloons launched on a normal day and how many on xmas day. If you cannot answer then you cannot say Xmas model output isn't affected.

Another thought ,perhaps we need to take into account the number of planes taking off and flying around ,if a butterfly flapping its wings can effect our atmosphere [just a thought ]I dont mean to appear rude but looking outside this morning at all the north american air traffic coming in i,m sure that must affect our atmosphere .

Iwould also like to point out too new members , the study of aircraft contrails is a very interesting read ,and for any one trying to understand the upper atmosphere at about 300mb which is about 30,000 feet  different thicknesses and length of these contrails also how fast they break up etc , any how models today looking very encouraging for out past this sunday ,but dont look for the snow word too much at the moment as this will come nearer the time in any met forecast ,there are Weather sharks out there people with no more interest than selling their papers etc , well gang catch you up later at that golden hour of 7pm for tonights runs ,cheers 

[Blessed Weather]

With both my UK and Alps 'snow search' hat on I've been looking at the GEFS NH 500 Mean Anomalies since yesterday morning's 0z run. There's a consistent story for the 1st Jan, with strong heights to our west and low heights to our east. So we now have reasonable continuity with GFS Op runs showing a northerly flow with UK snow for (at least) higher ground in the UK. The bad news for the Alps is the continued lack of lower heights in Europe is reflected by Op runs continuing to show the band of snow rapidly fizzling out as it approaches the Alps.

Charts for 0z yesterday, 0z today and 6z today for 1st Jan:

Moving on to the 5th Jan and looking at the same run of charts they show a minor but unwelcome trend (if it's snow you seek), with the heights to our west starting to extend across the UK into Europe. Similarly the lower heights over Scandanavia are edging further east. This suggests we may end up more under the influence of high pressure with any 'bite two' northerly flow slipping away to our east?

We'll have to await this afternoon/evening's runs to see whether this is a continuing trend or not.

 

[Summer Sun]

 

[NeilN]

No matter what, I think we're going to spend January in the freezer and I am happy after a benign December. 

[blizzard81]

Today's updated CPC AO and NAO forecasts are much improved on yesterday's. I wonder if this will lead to some peachy cold 12z runs?

[Summer Sun]

The 06z ens shows the Op was on the cold side from around the 6th the peak of the cold looks to be early next week after which we see a slight rise in the 850's but still remaining on the chilly side

Edited December 27, 2016 by Summer Sun

[Ali1977]

25 minutes ago, blizzard81 said:

Today's updated CPC AO and NAO forecasts are much improved on yesterday's. I wonder if this will lead to some peachy cold 12z runs?

AO dive bomb would suggest WAA making further inroads to the pole than shown on the 6z I think.

[Daniel*]

In the words of Steve Murr: This is a classic -EPO/ -NAO couplet 

Well EPS is certainly up that alley  

 

[bluearmy]

These noaa AO/nao forecasts aren't any more reliable than the regular gefs/eps/geps ones

good to see them plummeting but not convinced they are going to prove accurate  

[Interitus]

6 minutes ago, Changing Skies said:

 

He's been on the sherry!

 

Back on topic, this chart shows the comparative importance of various input components to NWP for error reduction, from a 2013 powerpoint presentation focused on aircraft data -

source: ftp://ftp.wmo.int/Documents/www/amdar/presentations/wmo_airc_leadcenter_work.pps

 

Edited December 27, 2016 by Interitus

[Paul]

Matt's latest synoptic guidance blog is online

Synoptic Guidance - Cold Start To 2017

[winterof79]

21 minutes ago, Ali1977 said:

AO dive bomb would suggest WAA making further inroads to the pole than shown on the 6z I think.

A tanking AO is a clear indication around our region that cold weather is around the corner.I cannot recall a time when it was a faux pas

[offerman]

GFS seems to of downgraded from earlier runs but still short colder periods.

[stewfox]

11 minutes ago, offerman said:

GFS seems to of downgraded from earlier runs but still short colder periods.

GFS 12z has just started rolling out ?

[bobbydog]

1 hour ago, bluearmy said:

I'm sure NOAA will be delighted to read the members of NW have decided to take the multi million pound gfs upgrade seriously!

since it became available I am taking it far more seriously than the normal gfs

lets see if the current trend to develop a week 2 more west based neg NAO begins to show on the normal gfs. Of course, week 2 op output isn't for close analysis in any case.

This is something I have wondered. Is the new GFS parallel verifying better than the current Op? As you say, it is supposed to be an upgrade, therefore it should be. If so, I'll take the 00z!

[bluearmy]

Gfsp 06z in week 2 is certainly not as much fun as the 00z was ?!

[radiohead]

Sadly the 06Z GFS P doesn't provide the type of epic eye candy for coldies in deep FI which was saw on the 0Z. But such is the nature of operational runs at that range...

[bobbydog]

2 minutes ago, bluearmy said:

Gfsp 06z in week 2 is certainly not as much fun as the 00z was ?!

It's not but obviously we should ignore it because Chinese butterflies have eaten some of the data...

[johnholmes]

2 hours ago, TEITS said:

So you don't believe in the chaos theory with regards to the NWP. Astonishing, back to basics for some I feel!!

Come on TEITS, the only time this theory is trotted out is when there is no sign of cold weather. So yes it is fairly often with our run of relatively mild spells around Christmas. Odd though, don't you  think, that this theory is absent if 'cold' seems likely and even less so if it is cold and some get snow over Christmas. Like a hundred and one other factors taken into account by forecasters the period of data absent, for whatever reason, is ALWAYS factored in to any professional forecaster when assessing all the data available. In truth there is a larger number of aircraft over the Atlantic on Christmas Day in the past few years than say 10 years ago. Have a look at the IATA data for these days if you do not believe me.

Also a bit rude of you to suggest for a professional to go back to basics. Can you tell us what your meteorological qualifications are please?

Sorry for this post not having any model data in it but as an ex forecaster this red herring every year when it is not cold gets on my nerves.