[Winter 2017 2018 General Discussion]

On 09/10/2017 at 21:32, karyo said:

I like the look of the December chart! 

Is the January chart available anywhere?

Even the Feb chart is not that bad as it would allow for some night frost at least.

Of course I can give it to you. I didn't have enough time to post it, but there it is. Looks fairly neutral for the UK.

[Stratosphere temperature watch - 2016/17]

10 hours ago, Interitus said:

Well here is an alternative view to take some account of seasonality. Using the month of easterly wind onset at 30mb as the start of a QBO cycle, the current cycle began June this year. There are five other cycles since 1960 (data prior to this is generally poor) which began in June - 2009, 1991, 1986, 1981 and 1967.

All show an apparent weakening of the easterlies in the autumn or early winter apart from 1981, which does at least display a moderation in strengthening. Then 4 out of 5 have a 25/26 month cycle, with maximum easterlies in the spring or early summer the year after onset. The exception being the long 32 month QBO of 1967 which started out looking like it might return westerly at the beginning. This did happen for the QBO beginning in July '64, which switched back to westerly in October, before commencing again in January '65.

In any case, it can be seen in the graph that this year is stronger than all these previous years at the four month stage (though this could be because QBO amplitude has tended to increase with time in the data).

Interesting. Thanks for that.

[Stratosphere temperature watch - 2016/17]

28 minutes ago, Interitus said:

Whatever happens, the QBO is following a more typical course at present and is already totally different to the 'failed easterly' of last year, as can be seen in the chart below of monthly 30mb equatorial zonal wind -

Fair enough. What I am saying is that it could be weaker than a normal -QBO phase. I had a chat with Paul Roundy on Twitter and he said that the EC model prediction is probably not enough to forecast a QBO reversal properly. Which I agree with, just noting patterns I am watching.

[The Seasonal Forecast Thread]

The NMME above doesn't look great for the UK. Mostly neutral precipitation and above average temps. For those who don't know what the NMME is, it is a mixture of the CanSIPS and CFS seasonal ensembles.

EC Seasonal forecasts (paid forecasts) are below. MSLP forecasts for Europe.

December is progged to have ridging over the UK, particularly to the north.

January shows troughing to west of the UK, with potential Atlantic influence.

February shows a ridge over the UK.

Very interesting prog, next month's one could be interesting.

[Stratosphere temperature watch - 2016/17]

Here is the QBO forecast, which is in easterly mode at the moment. But this forecast hints at a slight weakening of the -QBO.

Other things of note, the SAO jet is strengthening in it's current positive mode. Same with the jetstream over the Northern Hemisphere. This seems to somewhat correspond with the current +AO (stronger polar vortex), that is set to continue for the next 10 days at least, with longer term charts (GFS) showing a potential move to neutral AO.  

EPS Control also shows a weakening of the easterly QBO jet over the 10-15 day period. Interesting, will the QBO follow fthe forecast? Will the 'failed' easterly phase happen again?

[Stratosphere temperature watch - 2016/17]

The QBO looks to weaken from it's westerly phase over the next few weeks. EPS Control Zonal Wind Anomaly below. 

+00

+360

[Australian Weather]

6 hours ago, Styx said:

This weekend is the traditional opening of the ski season on the mainland,  some of the main resorts have opened already catering for minor activities, like snow play, sledding and some piste runs. The snow guns have done most of the work, churning it out in the cold and frosty conditions. There was about 20cm of natural snow cover at the end of May at high range, but that's all. There are no snow bearing fronts on the horizon,  they would be wanting something to show up by the end of the month I think.     

There are some signs of frontal activity towards the end of the month. EPS Control suggests the period beyond the 20th to be cold for SE Australia. But too early to call...