Jump to content

Archived

This topic is now archived and is closed to further replies.

Paul

Model output discussion - 16th Nov onwards

Recommended Posts

Plenty of egg on face if this winter does have a twist - baring in mind it hasn't started yet. We are a little in Un- chartered territory with regards see temps around Alaska, El NIno, low sea ice, and many various forces....Yes some do point towards a milder winter such as Westerly QBO but together they all bring a new uncharteted global pattern....not one you can predict with any certainty. In has been said by some more experienced model watchers that the nearest winter set up to all current factors is 1941...a very cold one.

Anyway, onto the charts - that is one nasty storm heading for Northern Scotland/Shetland next Monday, one to keep an eye on. And for those budding skiers amongst you, let's hope the high doesn't set up around the Alps for the next few weeks, not what they will want down there.

Share this post


Link to post
Share on other sites

Hey up, is the pub run about to deliver again in FI?

 

npsh500.png

 

 

 

Certainly a much weaker vortex than the 12z

Share this post


Link to post
Share on other sites

Jet stream isn't screaming Zonal here at day 12 although it does revert a little in the far reaches of FI. 👎

post-18651-0-67457600-1448319423_thumb.p

Share this post


Link to post
Share on other sites

Plenty of egg on face if this winter does have a twist - baring in mind it hasn't started yet. We are a little in Un- chartered territory with regards see temps around Alaska, El NIno, low sea ice, and many various forces....Yes some do point towards a milder winter such as Westerly QBO but together they all bring a new uncharteted global pattern....not one you can predict with any certainty. In has been said by some more experienced model watchers that the nearest winter set up to all current factors is 1941...a very cold one.

 Not sure what you mean by 'uncharted territory' ? Its all very standard. e.g El Nino, low sea ice etc is hardly new

Share this post


Link to post
Share on other sites

ECMWF EPS weeklies just out, and FWIW the EPS control run looks interesting from day 16 to day 32, with the combo of strong Canadian high and Siberian high breaching through to the pole at times, heights rising over Svalbard too from day 20, all of which would induce a more meridional flow over the N Atlantic/N Europe towards mid-December.

Share this post


Link to post
Share on other sites

Not sure what you mean by 'uncharted territory' ? Its all very standard. e.g El Nino, low sea ice etc is hardly new

If you can name another year with a strong El Niño, warm North Pacific, cold central Atlantic, lowering sun activity, in a westerly QBO with good early Siberian snow cover I'll take your point. I agree a cold winter isn't looking on the cards, but so many variables make it no where near straight forward to predict ..

Share this post


Link to post
Share on other sites

Jet stream isn't screaming Zonal here at day 12 although it does revert a little in the far reaches of FI. 👎

It is rather zonal with 'potential' any depressions will be carried like a conveyor belt straight to our shores I sense a very unsettled start to the winter is coming. I think we can wipe 2 weeks for any meaningful cold/snow aside from fleeting wintriness on uplands of northern Britain. I expect this to increasingly wane as we got into mid December into festive period I'll rather endure this now than New Years. A lot is riding on this Siberian high by the sound of it - it may be the catalyst we need to initiate something much more favourable. :)

Share this post


Link to post
Share on other sites

ECMWF EPS weeklies just out, and FWIW the EPS control run looks interesting from day 16 to day 32, with the combo of strong Canadian high and Siberian high breaching through to the pole at times, heights rising over Svalbard too from day 20, all of which would induce a more meridional flow over the N Atlantic/N Europe towards mid-December.

 

Certainly fits with my expectations but maybe a tad premature in terms of timeframe- though I'm guessing it shows just what could happen if things run in our favour.

 

What we're not seeing in any of the models is a flat, fast jet circumnavigating the globe in unstoppable fashion....that is a far cry from where we've been at this juncture in other years.

Share this post


Link to post
Share on other sites

UKMO has another chilly weekend lined up though GFS is less clean and thus doesn't get colder air South.

Shame there are no 850's for UKMO but this chart for Sunday looks like it might get some cold air quite far South albeit relatively short lived.

 

UN120-21.GIF?24-05

Share this post


Link to post
Share on other sites

ECMWF EPS weeklies just out, and FWIW the EPS control run looks interesting from day 16 to day 32, with the combo of strong Canadian high and Siberian high breaching through to the pole at times, heights rising over Svalbard too from day 20, all of which would induce a more meridional flow over the N Atlantic/N Europe towards mid-December.

 

Although this may well be true, although the combo of the Siberian and Canadian HP is debatable towards the end of the run, surely care has to be taken not to read to much into this.

 

Looking at the ens mean anomalies, and I appreciate you will get a flattening of the flow the further out one travels, to my untutored eye there is no appreciable change from the current pattern between now and Xmas Day.

 

On the 9th December we have HP North America and Russia with the Azores pushing up from the south with low pressure Siberia/Alaska and Greenland with trough into Scandinavia.  By the 25th Low pressure Siberia/Alaska and Greenland with trough down to the UK and HP NE Canada and Russia with less influence from the Azores.

 

Thus a rough summary for the period would be a continuation of the westerly flow with alternating periods of influence from the Pm and Tm airmassess with temps around average but varying during the transition of systems from the west. All of this inclining to a N/S split.

 

N.B. I also appreciate without looking at the full suite one can also read too much into this but I can only tell it as I see it.

Share this post


Link to post
Share on other sites

A couple of images selected from the ecm are worth more than a thousand words

 

post-12275-0-65549400-1448353401_thumb.p

post-12275-0-52697500-1448353408_thumb.p

Share this post


Link to post
Share on other sites

Although this may well be true, although the combo of the Siberian and Canadian HP is debatable towards the end of the run, surely care has to be taken not to read to much into this.

 

Looking at the ens mean anomalies, and I appreciate you will get a flattening of the flow the further out one travels, to my untutored eye there is no appreciable change from the current pattern between now and Xmas Day.

 

On the 9th December we have HP North America and Russia with the Azores pushing up from the south with low pressure Siberia/Alaska and Greenland with trough into Scandinavia.  By the 25th Low pressure Siberia/Alaska and Greenland with trough down to the UK and HP NE Canada and Russia with less influence from the Azores.

 

Thus a rough summary for the period would be a continuation of the westerly flow with alternating periods of influence from the Pm and Tm airmassess with temps around average but varying during the transition of systems from the west. All of this inclining to a N/S split.

 

N.B. I also appreciate without looking at the full suite one can also read too much into this but I can only tell it as I see it.

Agreed. W'rly dominance (between SW to NW, so transient colder phases) & little sign of pattern change out to late Dec in either EC Monthly or latest GloSea5, albeit more anticyclonic members appearing to influence southern UK later. But both models agree on +ve temp anomaly and wetter than average signal to W/NW areas; drier to E. Persusal of individual EC stamps for period 14/12 to 20/12 has only minority (6/50 on my count) of members with -6C 850 isotherm over any part of UK. So, whilst change may well ultimately appear, it's yet to do so in any compelling fashion in the 14-30 day products.

Share this post


Link to post
Share on other sites

I'll try again after nearly 10 minutes setting up a post, it disappeared as I tried to type a link ECMWF!

back in a bit

 

Trying again

Using the 3 anomaly sets of charts I use then they do not suugest any lasting deep cold nor do they suggest a very mild long spell of weather. With a broadly westerly flow at 500mb, switching between about 300 and 250 degrees then occasional Pm and Tm air seems the weather pattern for about 2 weeks or so. Nor does the MJO (GFS version) suggest anything might change with orbits ending almost at the origin. Synoptic charts, naturally enough, given what is suggested above are and will continue to switch from cold looking to mild looking. What they do show is that surface features will move quickly across the Atlantic bringing their switches from Pm to Tm air, pretty much on a NW-N/SW-S split. Hills of Scotland being the most likely to have snow cover at times. If one looks at the overall pattern predicted on the UK Met Fax charts it gives as good an idea as we are likely to get from free data as to what to expect.

Links, trying again

ECMWF-GFS, note not able to get the 00z version I usually input so this is the 12z from last night

http://mp1.met.psu.edu/~fxg1/ECMWF_12z/hgtcomp.html

NOAA

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

MJO (GFS version)

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/whindex.shtml

NAEFS

http://www.meteociel.fr/modeles/naefs_cartes.php?code=0&ech=240&mode=0&map=1&runpara=

http://www.weathercharts.org/ukmomslp.htm

and of course the various synoptic model outputs for comparison

 

from the post above by Fergie from Met Office briefings it seems they suggest much as I've posted and indeed they seem to have nothing beyond 2 weeks to mark any major change.

This should not be surprising given the overall upper pattern and ENSO outputs along with their monthly charts they issue which are along similar lines.

So to those wanting sub zero values for days on end and deep snow=sorry, not yet on the menu sheet. 

Share this post


Link to post
Share on other sites

The balance of power has shifted more in favour of higher heights over Europe at the expense of such over central/eastern Asia. Not a great trend for both the medium and longer term - and seemingly a reflection of amplification returning but too late to prevent low pressure from advancing as far as Siberia by 9 or 10 days from now.

 

Having said that, a Siberian storm coupled with an increasingly meridional jet could produce cyclonic wave breaking off the Asian mountains. The GFS 00z det. falls short of this, with a flatter jet, but the ECM counterpart is more like what I'm talking about.

 

 

Really the bulk of December is now looking more like I imagined it would, based on current guidance. The expectation has been that I'd spend the month focusing on stratospheric developments in light of a lack of much weather interest in the troposphere - though it'll probably be wet and wild in the north on more occasions than many would like.

 

I say more like, as there's still a notable lack of polar vortex organisation in the troposphere being depicted by the models - it has a go here and there but never really kicks off. So long as this continues, there's a chance of a deviation from the westerly regime - and it should prove difficult for the models to pick out in advance, given the lack of a consistent driving force at the high latitudes.

 

The GFS 00z det. doesn't offer any cold conditions beyond +240 but does set up a pattern reminiscent of Nov 2009 in which large Atlantic storms come up against a Eurasian Block, resulting in frontal systems piling into the UK only to slow down overhead and dump large volumes of rain. It's one possible consequence of the more meridional jet that a disorganised polar vortex permits.

Share this post


Link to post
Share on other sites

ECM ens

 

After a short lived north westerly flow at the weekend perhaps bringing some snow to the northern hills we see a return to a westerly flow winds strong at times with some rain or showers crossing the UK however as the high begins to dominate over large parts of mainland Europe this could move up to the UK keeping the south and SE drier and less windy over time

 

Reem1441.gifReem1681.gifReem1921.gifReem2161.gifReem2401.gif

Share this post


Link to post
Share on other sites

Although this may well be true, although the combo of the Siberian and Canadian HP is debatable towards the end of the run, surely care has to be taken not to read to much into this.

 

Looking at the ens mean anomalies, and I appreciate you will get a flattening of the flow the further out one travels, to my untutored eye there is no appreciable change from the current pattern between now and Xmas Day.

 

The Canadian high building certainly looks to be an increasingly notable feature on NWP guidance as is the Siberian high anomaly, as per ENS means and yesterday's CPC 8-14 day chart below  - unfortunately, for us though, with a vortex still sat over Greenland.

 

post-1052-0-53048100-1448358655_thumb.jp post-1052-0-24983300-1448358757_thumb.pn

 

The Canadian high with troughing beneath it from the Pacific across southern US - is typical strong Nino response with the strong STJ and shows well on the re-analysis plots for Decembers with Nino 4, Nino 3.4 and Nino 1+2 as this is a basin wide Nino this year. 

 

post-1052-0-05865000-1448358943_thumb.gipost-1052-0-98935800-1448358949_thumb.gipost-1052-0-55235900-1448358958_thumb.gi

 

Also note the troughing over the N Atlantic as expected, but ridging over Scandinavia, which has been a feature of some the extended EPS control runs and is also now hinted at by 00z ECM det. and 00z GFS op at day 10 and on.

 

What the reanalysis plots above doesn't take into account, of course, is any anomalous +ve heights across Siberia.

 

It remains to be seen whether the Canadian and Siberian highs will have much impact on the PV through December, but at least the PV looks under threat early on. Though we may have to grin and bear the Atlantic lows for a good while yet.

Share this post


Link to post
Share on other sites

I wouldn't at this stage worry too much about models saying SW'ly regime for month ahead, we had that in Nov with anomaly charts and like and then we had a nice change come upon us which wasn't in that script.  Let's get to weekend and see where we are headed as although no freeze anticipated or major northern blocking, I don't think Euro HP is a given either and must be treated with equal caution as I think pM air is always close enough to be well in the mix. 

 

BFTP 

Share this post


Link to post
Share on other sites

Sorry Fred, but the anomaly charts have never precluded a 48-72 hour cold snap; in fact, they've suggested that such an event is always possible... :)

Share this post


Link to post
Share on other sites

Sorry Fred, but the anomaly charts have never precluded a 48-72 hour cold snap; in fact, they've suggested that such an event is always possible... :)

 

They had Euro HP dominant and fixed and weren't they showing the same for rest of 2015?  Now re always possible...I would say a a January 1987 event in next couple of weeks is impossible :D

 

Personally thanks for message you posted :good: much appreciated

 

BFTP

Share this post


Link to post
Share on other sites

The models don't suggest a SW dominated month ahead - they suggest a predominant W/SW flow for the 7-10 day period, after that anything could happen!

As it is I still don't mind this set up, as I believe we are still a good 3 weeks away from the start of the optimum period for cold. Much as summer doesn't usually have much oomph in late may/early june....winter doesn't tend to pack much of a punch in late november/early december!

Share this post


Link to post
Share on other sites

They had Euro HP dominant and fixed and weren't they showing the same for rest of 2015?  Now re always possible...I would say a a January 1987 event in next couple of weeks is impossible :D

 

Personally thanks for message you posted :good: much appreciated

 

BFTP

 

Not sure which anomaly charts you refer to above Fred. Certainly not the ones I use. Indeed their time scale is, at most, 15 days with NOAA. Not sure what any others show as I have never done as much checking on them as I did a few years ago with NOAA along with EC-GFS?

Share this post


Link to post
Share on other sites

Not sure which anomaly charts you refer to above Fred. Certainly not the ones I use. Indeed their time scale is, at most, 15 days with NOAA. Not sure what any others show as I have never done as much checking on them as I did a few years ago with NOAA along with EC-GFS?

 

Indeed not John,  I read your updates and outlooks with great interest.  I'm derailing things here its probably the longer term ones that get posted up about the place and my post is more angled about the reliability detail of anomaly models and not about any posters and assessments.

 

regards

 

Fred aka BFTP

Share this post


Link to post
Share on other sites

To be quite frank if anything there is a strengthening threat between all of the output of a very mild SE/NW split in the weather coming up again from next week and because of the nature of these setups they can be an absolute stubborn animal to break out of once established which on past proof has given the UK weeks and weeks of mild weather in Winters past without a hint of cold. I am not of course saying that this is going to happen this time round but it does look like the chance of anything wintry is put back to well into December at least unless the models start to diverge from their current output soon. Sorry folks just saying it as I see it.

Share this post


Link to post
Share on other sites
Guest
This topic is now closed to further replies.

×
×
  • Create New...