Model Output Discussion 18z 30/09/15

[Yarmy]

The Met Office is suggesting something cooler than average for the South East come the end of November.   I'd be interested to see what someone more knowledgeable than I thinks on how this fits into the model output.

 

While I don't fit your criterion  , I'll comment that aside from the CFS none of the model output goes out that far. The MetO have other tools they use for the long range thoughts (EUROSIP, DECIDER, etc) along with plain old experience and expertise presumably.

 

But anyway, here's an example of an exceptionally mild start to November with a chilly end in the south east.

 

 

 

 

 

[IDO]

The Met Office is suggesting something cooler than average for the South East come the end of November.   I'd be interested to see what someone more knowledgeable than I thinks on how this fits into the model output.

 

No expert, but extrapolating from the current synoptics projected forward, I suspect that the Block will remain to our east and as the Azores High gradually becomes less of a driver and is replaced by lower heights, that block to the east, will become the driver for any more settled cooler weather. The SE will then be potentially more at risk from a SE'ly flow. Where as in the coming weeks the Azores is feeding the UK from a milder SW/W flow.

 

The CFS highlights this potential:  

[mb018538]

We've managed to squeeze a 20c at Charlwood today. The synoptics look as good (if not a tad better) for the coming days, so who knows where we could end up! ECM at 120 has the potential to deliver a slightly highertemperature than today.

[nick sussex]

Suggestions upstream for a retrogression of the pattern and a more amplified pattern developing in the eastern Pacific  which would tie in with some recent operationals which dig troughing to the west of the UK and attempt to pull high pressure north.

 

I'm not sure theres enough amplification though to pull high pressure sufficiently north to develop a colder surface flow into the UK.

 

Its noticeable that the UKMO further outlooks are hedging their bets because at this time of year the orientation of any high and how far north this gets makes a big difference to temperatures. Its clear from that UKMO outlook that they're not sure where the high is going to end up.

[cheshire snow]

Suggestions upstream for a retrogression of the pattern and a more amplified pattern developing in the eastern Pacific  which would tie in with some recent operationals which dig troughing to the west of the UK and attempt to pull high pressure north.

 

I'm not sure theres enough amplification though to pull high pressure sufficiently north to develop a colder surface flow into the UK.

Its noticeable that the UKMO further outlooks are hedging their bets because at this time of year the orientation of any high and how far north this gets makes a big difference to temperatures. Its clear from that UKMO outlook that they're not sure where the high is going to end up.

 

Great to have you back for another rollercoaster of a season Nick, Hopefully alot of hyperventilating and Booms to go with your

detailed analysis

C.S

Edited October 27, 2015 by Polar Maritime
To separate post from quote.

[ANYWEATHER]

Seems that the gfs chart viewer is not updated fully yet?

[Summer Sun]

GFS is fully updated on meteociel if your having issues with it on netweather at the moment

Edited October 27, 2015 by Summer Sun

[nick sussex]

Great to have you back for another rollercoaster of a season Nick, Hopefully alot of hyperventilating and Booms to go with your

detailed analysis

C.S

Thanks that's nice of you.Unfortunately last winter was a bitter disappointment for the UK in terms of cold and snow, unfortunately that limpet PV over the ne USA ruined chances.

[knocker]

A general comment on tonight's ecm. The HP to the east remains in place for most of it giving a general southerly drift over the UK and some above average temps. By the end the HP has reorientated to a SW/NE position veering the stream lines.

 

Moving on to this evening's GEFs anomalies the 6-10 rather supports this scenario. The 11-15 tends to slacken the HP to the east and generally supports the idea of HP centred just to the south giving a slack westerly flow. All relatively pleasant really.

http://www.tropicaltidbits.com/

 

Looking at tonight's NOAA it would appear to be keeping the centre of the HP further north and worth noting the very high confidence with the analysis.

 

Edited October 27, 2015 by knocker

[knocker]

The ecm has the HP just to the east, a position it maintains in the ext period so a rather gentle SW airflow and above average temps. At this stage the percentage is HP adjacent or over the UK for a couple of weeks once this week has settled down. Of course the key is where the surface high pressure decides to rest a while.

 

[Geordiesnow]

Still a bit of uncertainty regarding the final orientation of the high as we head from the weekend into next week which may affect just how warm things will get but there is no disputing the fact of a warming quite widely trend as we head into the weekend and next week. 

 

Going to be interesting just how warm its going to be, I guess it could boil down to how much sunshine there will be but either way, humidity should be high and it will feel like late summer regardless if its cloudy or sunny. 

[Ali1977]

FI ensembles are starting to look interesting again...lots of blocking and some split PV...11 out of the 20 hold some interest for coldies.

[knocker]

Nothing to add vis the 06z GFS that hasn't already been said. HP generally in charge with the odd impact from Atlantic systems for the north. And some quite warm days in the southerly drift of which Saturday is an example. Sunday could get close to the Nov. temp record perhaps before it becomes cooler.

Chart courtesy weatherbell

Edited October 28, 2015 by knocker

[knocker]

The ecm run also has a familiar scenario with HP to the east and SW and LP to the west/north west resulting in stream lines from the south and south west. Ergo generally above average temps and some a fair way above. There is some concern that the dafs are beginning to think it's spring.

 

 

[Man With Beard]

I would add to Knocker's analysis that the GEFS mean has pressure above 1025mb between E England and Poland all the way to T312, and 1030mb in its centre for virtually the whole period. That suggests a largely stable, southerly based flow with little precipitation apart from maybe in the NW. It fits in well with the ECM op. So confidence high in a long period of above average temperatures and mainly dry conditions - more than likely stretching from this weekend into the following. Chances of the high migrating far enough north to allow a significant easterly component (I.e. colder) are small, though not impossible. A below average November looks a long shot, even at this stage.

[Ali1977]

I still believe the high will migrate North, ensembles are starting to pick up on this - next few days could be interesting...

[Liam J]

Good agreement across the ensembles keeping the UK in a mild flow out to day 10 and possibly beyond, some horrific looking charts in there if your hoping for something of the cold variety! The B word comes to mind... 

 

Mean charts out to day 12.

 

Edited October 28, 2015 by *Sub*Zero*

[MP-R]

Good agreement across the ensembles keeping the UK in a mild flow out to day 10 and possibly beyond, some horrific looking charts in there if your hoping for something of the cold variety! The B word comes to mind... 

 

Mean charts out to day 12.

 

gfs28.pnggfs25.pnggfs26.pnggfs27.png

 

Let's not worry yet. If it were January I'd be worried by fortunately it's not and these patterns rarely last longer than a fortnight without change. It does seem a cooler more unsettled regime takes hold into week 2 (w/c 9th); it's only really a matter of time until the Atlantic breaks through. 

[Summer Sun]

ECM again shows high pressure becoming the dominant feature over large parts of Europe and indeed the UK over the weekend and into early November we'll have a lot of dry weather with this the only possible exception at times is the far north and west of Scotland but there will be plenty of dry weather too it could just take a few days longer very mild over the weekend but winds fall light next week frost and fog could become an issue with temperatures by day a little bit lower but still pleasant enough for the time of year

 

 

Day 10 ECM ens shows the high remaining the dominant features across mainland Europe and the vast majority of the UK

 

[Hocus Pocus]

Let's not worry yet. If it were January I'd be worried by fortunately it's not and these patterns rarely last longer than a fortnight without change. It does seem a cooler more unsettled regime takes hold into week 2 (w/c 9th); it's only really a matter of time until the Atlantic breaks through.

The euro high has to be the from horse for the duration of the next few months with a very strong Nino in place in my opinion. A very mild even warm set up in the reliable term and possibly lasting into the second half of November and beyond.

[MPG]

I still believe the high will migrate North, ensembles are starting to pick up on this - next few days could be interesting...

 

 

Good agreement across the ensembles keeping the UK in a mild flow out to day 10 and possibly beyond, some horrific looking charts in there if your hoping for something of the cold variety! The B word comes to mind... 

 

Mean charts out to day 12.

 

gfs28.pnggfs25.pnggfs26.pnggfs27.png

Two conflicting posts....anyone else?

[Man With Beard]

Let's not worry yet. If it were January I'd be worried by fortunately it's not and these patterns rarely last longer than a fortnight without change. It does seem a cooler more unsettled regime takes hold into week 2 (w/c 9th); it's only really a matter of time until the Atlantic breaks through.

Undoubtedly the Atlantic will break through at some point, but it is interesting to note, even this early in the season, that modelled Atlantic breakthroughs are failing. Last week, many were talking about the UK becoming a battleground - but instead, the euro block is now forecast to restrengthen. Now this could conceivable indicate a few things

1. The euro block is the driver for the coming period, and it may be underestimated by models at times

2. The Atlantic does not have strength in familiar zones for deepening lows so as to threaten the UK, so blocking could affect us from many different directions in future weeks or

3. it's just a temporary situation that will change in a couple of weeks

All options are possible but option 2. does interest me - I've notice in the last couple of weeks that some lows have exploded shortly after exiting Canada, in the way they normally do on our side of the Atlantic. This has led to them tracking north sooner, and makes them less of a threat to any block that sits over us (could this be something to do with the cool ssts?). If this is actually a pattern that will continue into winter, it would be a friend to a Scandi/Siberian high pushing westwards, as less resistance would be offered. Could that happen?

[Liam J]

Two conflicting posts....anyone else?

I backed up what I said with charts and have a look at some of the posts following mine, the Euro high is here to stay for the foreseeable keeping us in a mild flow.  

Edited October 28, 2015 by *Sub*Zero*

[Ali1977]

Two conflicting posts....anyone else?

Can't post charts, however if you look at the ensemble graphs there is a sharp drop in temps from the 11th of Nov...I was just going off that - if anyone could post this that would be great.

[solarcycle]

Can't post charts, however if you look at the ensemble graphs there is a sharp drop in temps from the 11th of Nov...I was just going off that - if anyone could post this that would be great.

 

Not sure what area of the country you're looking at. Latest for London doesn't really show this.