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phil nw.

Model Output Discussions 12z 30/11/16

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Tonight's GEFS 18z mean concurs with the operational with a mild swly changeable airflow becoming established next week.

21_168_850tmp.png

21_192_850tmp.png

21_216_2mtmpmax.png

21_216_850tmp.png

Edited by Frosty.

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GEFS not as tasty as some recent runs but the strongest trend remains to put high pressure to the west of Ireland by mid-December.

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40 minutes ago, Paul_1978 said:

Well well..... South Westerlies at T+201 becomes Westerly/North Westerly by T+225, and a sinking low and Easterly by T+276 and the Atlantic starting to look blocked again. 

Perhaps today hasn't been so bad after all?

image.png

Exactly. Does it matter what happens next week? Its the evolution thereafter that counts.

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2 minutes ago, Barry Reynolds said:

Exactly. Does it matter what happens next week? Its the evolution thereafter that counts.

Yes it does matter, it has a knock on effect. It does look as though it will become mild next week after a chilly start 

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Of course. Every evolution has a knock on effect. But the chart I referred to in Paul_1978's post shows how the knock on effect could be a good one.

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1 hour ago, lorenzo said:

c) the summaries - a concise, honest analysis of where things are heading and where we have been, an evolving roadmap as it were.

Essentially in doing things in this manner it allows us to acknowledge the wildcards, chaos theory and unforeseen characteristics of a UK Winter, and provide some further retrospective and forward analysis. In itself I feel that is a step forward from publishing a simplistic temp map saying the whole of Iberia will be warm or Scandi cold etc etc. If we can analyze how winter started then acknowledge the changes - the hope is this leads to better understanding next time around etc etc.

A very sensible approach in view of the difficulties this winter.

I've recently read three professionally written (meteorological agency) forecasts for my more immediate location - all highlighting uncertainties and model divergence in outcome for the season. Discussing risk for periods of cold/very cold but also probabilities favouring milder climatological bias. Emphasis on ongoing updates as situation evolves.

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12 minutes ago, Frosty. said:

Yes it does matter, it has a knock on effect. It does look as though it will become mild next week after a chilly start 

I thought that a mild spell was always on the cards?

Im happy enough for mild weather to show its hand now.... I still feel that a cold second half of December will happen.

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Quite a turnaround from yesterdays ECM 12z ensembles.

ensemble-tt6-london.gif

But on the plus side temps do start to tale off toward mid month again (albeit far too much scatter to cal it a signal of any significance)

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1 hour ago, bluearmy said:

Bit surprised gav would make a vid off a single CFS run - perhaps he needs a soft sell to get some hits for his advertising budget!

anyway, if the demise of the accentuated ridging early next week verifies then it backs up Exeter to a fair extent and probably means mogreps was seeing things a little differently to the eps. 

Bit disingenuous there Blue. Gav yes used one run but has done since he started the Xmas forecast. As he said putting them all together there was a trend appearing. I was always told that was the way to look at the charts and not the run by run analysis on a daily basis of the models which sends people over the edge. 

Example being the ongoing saga re blocking. I have loss count of the amount of times Tamara / GP / M Hugo / Steve Murr / BFTP to name but a few have tried to get people on here to focus on the longer trends and back ground signals which effectively is what Gavs video is. Mid Dec has been mentioned so many times yet if charts aren't showing at day 6 or 10 these signals then there is melt down. 6 - 10 days from now isn't mid Dec.

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2 hours ago, Banbury said:

If Winter stopped at the time Gav ended his vid then that would do for me........................absolutely NO chance of CFS being correct

Would have to disagree - reason being it has been consistent now for a while on the cold theme and added to the other back ground signals would have a better than average chance of coming off. Would love to see it verify as Gav has shown and I'm sure it will be interesting to see the final outcome !!❄️❄️❄️

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8 minutes ago, DR(S)NO said:

I thought that a mild spell was always on the cards?

Im happy enough for mild weather to show its hand now.... I still feel that a cold second half of December will happen.

Not what I can see, as far as I have mainly read in this thread there was a lot of hype the start of December could start cold and blocked and only to a very small extent it will but lets be honest, there has been a lot of hype in this thread about the winter prospects and perhaps understandably so with all these background signals but what does not help at all is when certain members(and its usually the same ones) who will post a cold snowy chart at the infamous Day 10 stage when a GFS FI run shows this or seeing people cherry picking those charts and because 2 or 3 runs show this in succession, its contributes to be a trend despite the massive timescale. Also the constant comments about "The charts are nothing like last winter" is also untrue and mis-leading, December 2015 was extreme but too me, what I have seen in the short to medium term has been in the main quite normal and there has been little to no blocking either with only half attempts of Amplification which allowed some cold air to filter in at times during November.

We got to remember any splits in the PV only increases the chances of colder air to hit the UK, its does not gurantee the cold will come nor does it gurantee proper sustained blocking in any favorable positions either, January 2016 is a good example of that where there is much more blocking then than there is now but the cold air was fairly fleeting occurances and snowfall was limited and that despite the PV being smashed to bits over the Arctic.

I'm not too dissapointed in the current output however as the UK high could turn out to be more of a nuisence just like that infamous Russian high was a couple of weeks back. I still would not fully go on board and say the SW'lies will occur but the chances of any easterly flow is very very slim now after some brief hope on yesterday's outputs. One other minor change is we may not see much in the way of frost and fog now because there is a shallow low gets embedded with the SSE'ly flow and its head into some Western parts which will increase the cloud and may bring some rainfall. Alot of uncertainty will no doubt surround that though. However what seems more certain is the winds are forecast to increase somewhat and this could well limit the frost and most definately fog risk.

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Been at work for most of the day and just catching up...I had hoped that we would be seeing stronger signs of something more wintry in the deeper realms of the NWP by now but apparently not. Does this come as a surprise? No.

I'm pleased that Matt Hugo has addressed the apparent disconnect between the longer range modelling and the more short/medium range NWP products. I noted this the other day as some of you may remember; with the 'dream synoptics' having been pushed back update after update. I don't know the reasoning for this BUT whenever you see heights failing to lower across Europe (repeatedly) then alarm bells start to ring. For whatever reason, the longer range modelling has seemingly been too eager to introduce lower heights across the mainland...which obviously goes hand in hand with the seemingly ever present HP cell being not able to migrate further N.

Where do we go from here...I don't know in all honesty but to see the HP modelled to slip SE is not a good omen in my very honest opinion and as Matt has said I think in the next week, crunch time will come for the rest of December's weather.

However, there is a positive. I don't (and haven't for about 3 weeks) believe that this will be a 'front loaded' winter. I don't think it will be a typical nina template i.e late mildness. I was surprised at the UKMO bullishness towards early cold in all honesty given last month's GLOSEA output which to me suggests that cold (or at least snowy episodes) would be more likely in the Jan-Mar period than the Dec-Feb timeframe and the CFS (for all its faults) has repeatedly gone for March blocking. This suggests to me that there is potential further along into the season & indeed early spring...so no need for anyone to be despondent in my view.

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17 minutes ago, johnny1972 said:

Would have to disagree - reason being it has been consistent now for a while on the cold theme and added to the other back ground signals would have a better than average chance of coming off. Would love to see it verify as Gav has shown and I'm sure it will be interesting to see the final outcome !!❄️❄️❄️

I would have to disagree lol

Those charts on Gavs vid showed a 2 week period of Ice days / blizzards you name it = severe winter weather , not sure that has been hinted at by anyone

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Good morning fellow weather geeks, another day of ups and downs and smiles and frowns.

Interesting GFS this morning.

Doesn't close off the Atlantic trough but certainly backs it up plenty. Also a nice Arctic high forming.

gfsnh-0-168.png

Inot FI proper and we have a split hemisphere (more or less) and look how close we are to picking up a NE flow

gfsnh-0-234.pnggfsnh-1-264.png

GFS deep FI lets the Atlantic in but it does show how things could crop unexpectedly - a few minor tweaks and we were in a cold pattern there

gfsnh-0-288.png

I won't sully this post with UKMO and GEM :nonono:

Edited by Mucka

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Another dreadful GFS00z. (The profile to the NE looks very nice with some very cold uppers spilling out of the arctic but the Atlantic is really not showing any signs of slowing down enough to allow for any retrogression...)

Positive NAO throughout.

UKMO looks bleak at 144 -

Rukm1441.gif

Hoping ECM provides something more positive for coldies... :)

Edited by northwestsnow

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34 minutes ago, northwestsnow said:

Another dreadful GFS00z. (The profile to the NE looks very nice with some very cold uppers spilling out of the arctic but the Atlantic is really not showing any signs of slowing down enough to allow for any retrogression...)

Positive NAO throughout.

UKMO looks bleak at 144 -

Rukm1441.gif

Hoping ECM provides something more positive for coldies... :)

LOL cheer up matey. Signs of life in FI within the ensembles.

gensnh-5-1-264.pnggensnh-6-1-300.png

And as we all know the outsider cold charts in deep FI always verify.

graphe3_1000_260_87___.gifgraphe6_1000_260_87___.gif

Edited by Mucka

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A few post have been moved to the moan/ramp thread, Let's please keep this thread clean and informative, Thanks.

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1 hour ago, northwestsnow said:

Another dreadful GFS00z. (The profile to the NE looks very nice with some very cold uppers spilling out of the arctic but the Atlantic is really not showing any signs of slowing down enough to allow for any retrogression...)

Positive NAO throughout.

UKMO looks bleak at 144 -

Rukm1441.gif

Hoping ECM provides something more positive for coldies... :)

You'd expect the later stages of FI in the GEM and UKMO to be poor as they only run for 10 or 6 days respectively and that is when the GFS is milder too. 6 or 7 ENS now below -5c 850s later on, and that's to mid month. Things are looking ok to me so far.  I expect the ECM won't be great at day ten neither for now.

Edited by Ali1977

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ecm at 160 plus looks pretty rank tbh with the high just sitting there.Where things go past ten days who nos!!!!!

 

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7 minutes ago, swfc said:

ecm at 160 plus looks pretty rank tbh with the high just sitting there.Where things go past ten days who nos!!!!!

 

I think the energy will push over the top based on the 168 to 192 progression. Also you meant who knows not nos, which is an abbreviation for nitrous oxide.

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