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Model Output Discussions 12z 30/11/16

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1 minute ago, blizzard81 said:

Shame they are higher resolution though.

Doesn't mean they can't be excluded if they are an outlier

GFS miles away from ECM Mean.

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Just now, bluearmy said:

But it's not over the pole day 10 and at 30/50 hpa it's even further displaced to siberia ???

IMG_4695.PNG

 

 

Yes but the fact that the trop pattern is solidly predicted on the models to be flat will mean that the upper level zonal wind speed increase will face no resistance and downwell easily (time of year and nothing being fluxed poleward at the moment).

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2 minutes ago, feb1991blizzard said:

Yes but the fact that the trop pattern is solidly predicted on the models to be flat will mean that the upper level zonal wind speed increase will face no resistance and downwell easily (time of year and nothing being fluxed poleward at the moment).

I cant see any forecast strat height/anomaly  pattern that I wouldn't be comfortable seeing imprinted on the trop from a coldie perspective. maybe you could show me one?

and I dont see a flat hemispheric pattern either. there is plenty of amplification around - we are forecast a split trop vortex !!!!!!!!!!

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1 hour ago, mountain shadow said:

Not one of those show the Atlantic taking hold. Those show the Euro slug High taking hold.

Sorry, but they do. If it hadn't the charts wouldn't look like that. The euro high has been pushed E due to a low moving N to the W of the UK bringing milder conditions from the Azores. ;)

Edited by Grimers

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34 minutes ago, bluearmy said:

 Otherwise it just becomes 'anarchy' ??

sadly, just Muppetry - the 'ignore user' function is great for this thread, but every now and then I get to see what Kermit and Fozzie and the rest are up to when they are quoted by more sensible members (up to three pages of ignored users now in a little over a week!) - hint for casual observers of this forum: register and you get to 'hide' serial offenders!

... I know, model comment only ... apologies to sensible posters ...

 

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48 minutes ago, northwestsnow said:

ke9iz8.jpgecm ens, not as bad as i feared, seems the ops this morning were indeed worse case scenario for coldies..

Yes, it could be a lot worse but it could also be a lot better (not trying to dig here). The NCEP and ECMWF are predicting slightly above average uppers on that chart. I would hope that there's a slight upgrade in favour of coldies' wishes.

Edited by Grimers

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8 minutes ago, Summer Sun said:

1ac6d7ec-c4a1-4dd6-819e-133ccb4f3d17.png

This is what we need the amplified tropospheric patterns to fight against by sustaining the disrupted lower stratospheric vortex state. It's possible to ward off downward propagation for a great many weeks - this is why it's such a bonus to begin the winter with a disheveled lower vortex. Perhaps it explains those historical Canadians Warming-led winters that kept on producing HLB episodes in the troposphere despite the stratospheric vortex spending most of the time merely displaced toward Siberia as opposed to split.

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Well it looks like becoming significantly milder next week after a chilly, settled start and rain looks like gradually spreading south and east, even reaching southeast england towards the end of next week but the most unsettled weather looks concentrated across the northwest. Into the following week also looks mild and unsettled, especially in the north with the best of the fine weather further S / SE. From around mid december there is still a signal for high pressure to regain control but confidence is not as high as recently. :)

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2 minutes ago, Singularity said:

This is what we need the amplified tropospheric patterns to fight against by sustaining the disrupted lower stratospheric vortex state. It's possible to ward off downward propagation for a great many weeks - this is why it's such a bonus to begin the winter with a disheveled lower vortex. Perhaps it explains those historical Canadians Warming-led winters that kept on producing HLB episodes in the troposphere despite the stratospheric vortex spending most of the time merely displaced toward Siberia as opposed to split.

Exactly, the PV may be getting it's act  together, but if is displaced, it can still effect what we get. To be honest, some interpretation without cross analysis is just misleading.

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1 minute ago, warrenb said:

Exactly, the PV may be getting it's act  together, but if is displaced, it can still effect what we get. To be honest, some interpretation without cross analysis is just misleading.

We are lucky that the PV is taking longer to become organised, in complete contrast to this time last year. 

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21 minutes ago, Summer Sun said:

1ac6d7ec-c4a1-4dd6-819e-133ccb4f3d17.png

A weakened PV hasn't brought us cold and snow, maybe a strengthening vortex will.

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I think people are disappointed that predictions for a cold December have been reined in somewhat, largely because of long range models backing up promising background signals. I do however think a little perspective is required, not least because it is only the 2nd of December! Of course people may have an opinion as to how the rest of the month may turn out but let's not confuse that with what the models actually say. On top of that after 4 or 5 days the verification stats significantly reduce anyway.

To my untrained eye the background signals, while more mixed, still hold some promise - and even when every background signal in the broad sense is in our favour that is not itself a guarantee of cold. It's pretty clear that we have a spell of milder weather to get through but who knows what will happen after that. Personally I would happily put up with another two and a half weeks of mild mush if it turns cold in time for Christmas.

In terms of model watching I intend to look for trends in FI and take note of the measured opinions of knowledgable posters such as Tamara, GP, Bluarmy etc. Let's see what happens and enjoy the weather what ever turns up :)

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What I am not seeing here is anything like the zonal @warm dross that we had last year. As I said in the last thread, it will turn into an awfully long winter if we are chasing 316 charts on the 2nd December. Yes I know what the ECM and Glosea said, it is hindsight that a) we have to work with and b) we have seen it all before. The set up we have now is so so so different to last year. It was already a train and we had already had four named storms. One this year and its across the south west and East where it struck not the normal place.

My take on this really has not changed from middle of November. It can and will go either way. I must admit though I am loving the frosty nights, is a throw back to the hallowed Dec 10. As someone says in there avatar is not enough we lived through the coldest December for 300 years.... Get the cold entrenched in Europe and something here then we are in for some fun.

I am grateful for the very knowledgeable posters from Matt Hugo and Ian  and I think not enough respect is shown to them when their forecasts are not listened to.

Keep th Prozac in the tin and lets get through this mild blip. So different to last year its stark. Charts may not show wot we want but need for calmness is now here.

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A few tweets and replies from Ian

5464654.png

Going by that mid-December onwards is still up for grabs as one would expect

Edited by Summer Sun

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In my opinion, people should stop giving time periods for pattern changes, because it usually leads to disappointment. Due to the background signals being much better than last year, I believe that at some point during the next 3 months we will get a pattern change to a cold blocked pattern, but to give a specific time on when that will happen is impossible. It's not a dig at anyone, but simply a fact that no one, no matter how knowledgeable, can forecast more than 10 days out with any accuracy. Including the Met Office. If people start mentioning the end of December now for a pattern change I think I might scream. This winter WILL most likely be better than last winter but nothing is certain past day 10.

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Im going to try over the next few days, to look for those ensembles picking up a colder second half/ week 2 + 3 of december. Slightly flawed in that as far north as i can get the ECMWF ensembles is Zurich, but a downward trend there would at least indicate the chance of something more blocked and  seasonal over us in the run up to Christmas..

Already, in my opinion, the number of colder runs is increasing post 13th/14th December.

 

 

 

Screen Shot 2016-12-01 at 10.15.20.png

Screen Shot 2016-12-01 at 11.24.38.png

Screen Shot 2016-12-02 at 14.36.44.png

Edited by -uksnow-

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TBH I can see where Feb1991 is coming from...the trend since that failed WAA attempt into Greenland a couple of weeks back has been a deteriorating one as far as December's prospects are concerned. I did even say at that time that it was a disappointment as I felt it was a big big opportunity missed (not to mention that drive of WAA was most probably critical as to how the here and now is playing out). 

I think we all know that once an unsettled/Atlantic driven spell gets going in a UK winter it is very hard to overcome...especially (as Feb notes) when there is little in the way of drivers that seem able to force a change of fortunes. From the strat thread it also seems as though GP is now looking towards latter December for a potential driver for change...which is getting on towards the time I expect we'll see the greatest propensity for favourable blocking..i.e January. 

I remain optimistic that we'll see a good period of wintry weather this year.

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BOMM_phase_33m_small.gif

Just in case anyone needed a laugh :rofl:

The Australian modelling aside, I've noticed that while the ECM ensembles have been starting to sniff out possible 4-5-6 MJO propagation, GEFS have not:

ECMF_phase_51m_small.gif  NCPE_phase_21m_small.gif

Today's update will be of interest to see if the EPS have taken the signal any further.

In the mid-range, a wander into phase 3 by day 9/10 could help get us back to a mid-latitude block by mid-Dec as opposed to Euro blocking:

DecemberPhase3gt1500mb.gif

This may be at least partially what the Met Office/GloSea5 is seeing, but with GEFS largely blind to it until it sees the MJO propagation (assuming it does occur).

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33 minutes ago, Barry95 said:

In my opinion, people should stop giving time periods for pattern changes, because it usually leads to disappointment. Due to the background signals being much better than last year, I believe that at some point during the next 3 months we will get a pattern change to a cold blocked pattern, but to give a specific time on when that will happen is impossible. It's not a dig at anyone, but simply a fact that no one, no matter how knowledgeable, can forecast more than 10 days out with any accuracy. Including the Met Office. If people start mentioning the end of December now for a pattern change I think I might scream. This winter WILL most likely be better than last winter but nothing is certain past day 10.

we have been locked into a  dry spell and some what coldish spell since october so you are right a pattern chance is due but i fear its not what some people wish for unfortunately  if its not dry and cold what else can it be tell me weather patterns tend to last 2-3 months at a time then change in my 42 years of living in this country 

2016_10_Rainfall_Anomaly_1981-2010.gif

2016_11_Rainfall_Anomaly_1981-2010.gif

2016_10_Sunshine_Anomaly_1981-2010.gif

2016_11_Sunshine_Anomaly_1981-2010.gif

Edited by igloo

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8 minutes ago, fergieweather said:

...precisely so, and precisely echoing UKMO thoughts after some recent flip-flopping of output (including yesterday's ECMWF Monthly, which suddenly offered substantial weakening of the previously strong +ve MSLP anomaly north/NW of the UK that it yielded in the run only 3 days prior and in all previous recent runs, for later December. Is it wholly trustworthy, given marked swing? No, not until we see the sense of direction offered in runs on Mon-Thurs next week.

The situation currently is that whilst ECMWF now offers just a bland, weak +ve MSLP anomaly to the west of the UK, it equally - and quite starkly - offers no signal either to suggest a markedly zonal, +ve NAO set-up either....

 

 

Ian, could you qualify 'massive ramp up' as being return to climatology (as GEFS), or above tercile, and whether such similar signal exists for 70hPa or 50hPa layers ?

Edited by Glacier Point

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1 hour ago, feb1991blizzard said:

Look at the 10hpa temps at the end of almost every run now, wave activity not doing anything to stop the vortex strenghthening over the pole, to me its obvious but don't want to upset posters I respct (fellow cold fans) so unless I'm badly wrong, I wont be posting for a while now (ie - when outputs improve)

Take a deep breath Feb - not sure what images you are looking at... but 10 day run sees the vortex off centre and elongated at 10hpa

ecmwf10f240.gif

 

and the warming visible there on the Russian side is clearly shown here:

 

ecmwfzm_ha1_f240.gif

 

There have been better strat charts over the years - yes - but when one considers this:

ecmwfzm_u_f240.gif

with a clear signal for weakening westerlies in the troposphere and a vortex considerably less strong at 60N than one might expect at this time of year you cannot possibly be gloomy. A dull week coming up... but we are still a long way from mid December!

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npst30.png  npst30.png  npst30.png

As much as longer-range GEFS is under question at the moment, worth noting how we see a new bout of warming at the mid-levels even as the Canadian one moves into the Atlantic and fades out (in mid-Nov GEFS was showing this to be strong enough to generate a decent stratospheric ridge near Greenland but that proved too optimistic), a new bout of warming emerges over Asia and starts circling the vortex like a hungry shark smelling blood.

That sort of thing - but ideally stronger - is what may fend off the upper vortex. Hopefully.

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