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

2 minutes ago, blizzard81 said:

Post of the day if that is true.

There's a lot of data on SSW events, some contradicting others, from what I've found, it seems. I think I worked with some on Martineau's data, I seem to recall. Perhaps someone with more access to the research could run an analysis to try to confirm my findings.

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

16 minutes ago, Steve Murr said:

To be fair if theres one thing ive been saying for the last 8-10 days its a summary of the above- ie the strat vortex was on the significant rise & that it would overwhelm any tropospheric signal !

@Catacol

week 1-2 jan is the way downwards ( expected ) for the strat zonal + 10 days propergation -so background signal is +AO  until then ( neutral at best ) 

within that some MLB availability which could locate favourably for the UK

Glosea + EC also late to the party in terms of picking up the signal...

 

I did some work a few years ago, chosing winters with negative CET months and concluded that there were no SWW or any which occurred in time to explain the cold, and that a split vortex was absent in all or almost all these winters. Also, examining the historical data, as per here:

http://ozonewatch.gsfc.nasa.gov/meteorology/wind_1985_MERRA2_NH.html

shows that there's not a lot of evidence supporting worrying what winds at 10hPa are doing, let alone worrying about forecasts for this far up in the stratosphere.

 

 

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

I understood that a Westerly QBO is more associated with  extremes of weather- extreme mild or extreme cold, than Easterly QBOs, which, however, tend to give colder weather when averaged. Think 1947, 1979, 1986, 2010.

And if the current, Westerly QBO is record- long, as it appears to be, and there continues to be a strat- trop disconnect, then past about a week, there's ample reason to treat the model output with caution. Were're in uncharted territory.

[Model Output Discussions 12z 30/11/16]

44 minutes ago, ArHu3 said:

That's 65N, a bit too far north

It's in agreement with this:

 

http://ozonewatch.gsfc.nasa.gov/meteorology/wind_2016_MERRA2_NH.html

 

and is more detailed, so I'll take it.

I should add that as Bluearmy has said, there is a long time- lag between 10hPa and the troposhere, and, furthermore, there may be something of a trop- strat split this winter.

 

A note on ECMWF, and I can't find much to complain about- a split trop vortex with opportunities for Atlantic ridging, GFS ensembles are quite keen on said ridging for just beyond this timeframe, and 4 GFS opperational runs yesterday into today, provided us with said height rises by day 16! That's not what I would call poor model output.

[Model Output Discussions 12z 30/11/16]

1 hour ago, bobbydog said:

Try this-

http://www.atmos.albany.edu/student/hattard/realtime.php

Bingo! Exactly what I wanted. Thanks muchly!!

[Model Output Discussions 12z 30/11/16]

14 minutes ago, Steve Murr said:

Woeful runs today

GFS now has 10 runs reaching above average 60N zonal wind speeds - ( post 192 ) thats up 5 from yesterday

its rapidly going pete tong im afraid.

UKMO 144 is about the best chart today..

Would you have a link for the 60N mean zonal wind speed forecasts, Steve? I asked on the strat thread but didn't get a response. found this:

http://ozonewatch.gsfc.nasa.gov/meteorology/figures/merra2/wind/u60n_10_2016_merra2.txt

 

but I don't think it's the same source as you're using. Thanks.

 

 

[Stratosphere temperature watch - 2016/17]

14 hours ago, snowwman said:

Does anyone have a free access source of CFS and GFS ensemble 60N mean zonal wind forecasts for the medium- long range? Been searching with very little success. Thanks.

Scrub this- I've found a source:

http://ozonewatch.gsfc.nasa.gov/meteorology/figures/merra2/wind/u60n_10_2016_merra2.txt

 

. But where is the forecast surge in mean zonal 60N wind strength? Doesn't seem to me that the strat is behaving as forecast, though that may be me reading the data wrong.

[Stratosphere temperature watch - 2016/17]

Does anyone have a free access source of CFS and GFS ensemble 60N mean zonal wind forecasts for the medium- long range? Been searching with very little success. Thanks.

[Model Output Discussions 06z 04/11/16]

In my opinion the measure of solar activity we should be paying most attention to is heavy cosmic ray influx, as per here:

 

https://cosmicrays.oulu.fi/

 

; where we are now, going by this, is rarely where we've been even at solar minimum of the cycles between  1965 and 2008, which is renarkable, as we're not even at minimum for this cycle yet.

As per model output, ECM ensembles are encouraging in that the vortex moves towards Siberia by day 10, and all which remains now is to get that high over continental Europe to be pushed South. GFS at day 16 has very few stamps maintaining this high, with quite a few (a majority) going for height- rises in the Greenland vicinity:

 

  .

[Model Output Discussions 06z 04/11/16]

The latest GFS output may seem backed by the ensemble mean, but it's instructive to look at all 20 ensemble stamps to understand what's going on:

 

 

, and that is the small percentage of members which are going with the operational run are skewing the mean. Some 15 out of 20 members are unsupportive of the op, and I suspect that in only a few run's time, the GFS op will be back with the blocked options. The same might apply to ECM, though I can't say for sure as I don't have access to the 51 members.

[Model Output Discussions 06z 04/11/16]

1 hour ago, BLAST FROM THE PAST said:

UKMO has the HP further north so for me ECM is on its own,  I think whatever the ECM is onto it is part of the movement that will see an attack from the N and NE.....AND ECM is wrong, I  anticipate it will move the HP to more like UKMO and GFS at t144 range

 

BFTP

I too have doubts about the ECM solution. The latest day 10 chart seems to me particulary unfeasible. A retrogresssion of heights to Greenland is what I'd expect.

[Model Output Discussions 06z 04/11/16]

2 hours ago, blizzard81 said:

Don't know why but I have noticed for years that the GFS 00z runs always seem to be by far the least amplified. Anyone else noticed this?

Sort of- I've noticed that the 18z seems to be the most amplified, though I haven't done any research to check this. What I've noticed about GFS is that it tends to go full circle wih an idea such as a break-down of a warm spell, or a block forming. For example, it's been putting out some very zonal charts for the 20th or thereabouts for a few days now, but the latest run final frame shows this:

  !

[Model Output Discussions 06z 04/11/16]

3 hours ago, bobbydog said:

Challenge accepted....

I give you... 1962

Then 1965 and '77 for good measure

Back to today, great ECM at day 10

Very different to the GFS

Another fun day ahead!

Hello, all, long-term user, not- until now poster.

Indeed, bobbydog, with the vortex like that in 1962, who'd have thought that we'd get the winter which followed?

 

I've done my own reasearch on historical anologues as well, and what I find frustrating is that the colour scheme changes for each year, much like it does sometimes on the operational runs. By this I mean that deep red might signify a particular geopotential height on one run, but another (albeit similar) height on another. It makes trying to compare winters frustratingly difficult!