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Model Output Discussion - 31/10/2014 and Beyond


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Couple of comments

ECM heights bias will lead to over amplification and possible feedback loops where the exaggeration becomes more exaggerated. However, it isn't as though it's out on its own re the upcoming ten days.

My experience of the past few years is that MOGREPS has been slow to the party when cold has indeed verified. I am not surprised that Exeter only had an easterly at 10%. We can see that on the Dutch ECM ens.

And thirdly, I bet a few of you are up earlier in the morning than is usual for a Sunday!

Excellent ECM this evening to be sure but a word of caution. Remember THE FAILED EASTERLY OF 2012. :shok:

Very interesting model watch it has to be said. :good:

Need to watch the ENS X model trends and check consistencey over the coming days.

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Some very Wintry charts on offer this evening, Another step in the right direction. After last year i was never expecting to see charts like this.   :)

 

ECH1-216.GIF?08-0

Edited by Polar Maritime
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Lol..... Okim not mr popular, but i dont see it happening. The ecm has in recent months had some bizarre swings over the summer past t168. I truely believe theres too much being read into the possible ecm output.

The thing is, i dont care if im proven wrong, ive nothing to lose. But until theres far more cross model support within a reliable timeframe then i reckon some of you are setting yourselves up for a massive disappointed.

The gfs is having none of it. If the gfs is right will it then be taken more seriously? But my monies on something in between the main two becoming reality.

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Am I allowed to be picky? I'm quite hard to please when it comes to cold synoptics so although the ECM shows an excellent trend in terms of the block being in place we don't want the pattern too far west.

 

It's better to see a chunk of the PV setting up in Scandi rather than moving sw towards the UK, it might look good on the charts but for longevity of cold its better to have a more eastern based negative NAO.

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www.cpc.ncep.noaa.gov/products/predictions/814day/500mb.php

Bit by bit the NOAA is increasing the blocking over Greenland, I'd say its following ECM more than GFS mean, which is actually going slightly in the opposite direction re strength of heights in Greenland

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No one is saying that's how it's going to happen Mush. It's what the Model's are showing, And the trend they are following.

C'mon mate, people are all ignoring the data that doesnt suit their agenda and are concentrating on the things they want to see happen most of which is fi!! Lol.

Im not saying it wont happen, but its far from certain especially given the way the ecm has swung wildly in recent times in fi.

I see no point at all in getting excited over anything until its within a very reliable timeframe.

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But SURELY, that Low to the south west is pumping warm air across the UK, not blizzards but buckets full of rain and winds! What is all the cold outlook hoola for?

HI Dave, 

Its what we call in the trade as a trigger low, if you look at the next frame on the ECM the low kind of darts south into mainland Europe and ( cuts below the Uk , you may have read on here about undercutting lows before) some refer to it as a slider low. 

What you are seeing to a point is as you said warm air being pumped in our direction but it is more than short lived (T+144), because the low changes shape, its basically being squashed between heights to our north and the jet stream to our south. 

Because of this ``squashing `` effect the air flow is no longer a south/ south westerly... it more of a south easterly or easterly from continental europe (T+168) which at this time of year is of benefit to the uk for getting in a cooler/ colder flow from a rapidly cooling continent at this time of year. if not dank and dreary for the east coast. 

 

So the low pressure continues to dive south into portugal / spain taking the jet with it and incidentally the low sends energy right across northern europe, whilst this is happening the heights over iceland/greeland orientate themselves in a manner that cuts off a southerly flow and swing to the east. (T+ 168 to192 ).

 

 By T+216 it is evident that the slider low/ trigger low sat over France by now is reeling in an easterly on its northern flank because of cyclonic flows around low pressure. 

The Beauty is David this.... heights to our north have a chance to build... and as you can see from the ECM (T+240) a very potent northerly is on the cards.Thats what the big Hoola is about , a great big but is getting cold into the uk and the route to it 

Its just one run of many though. heres hoping . 

Hope this helps  :good:

Edited by bryan629
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Am I allowed to be picky? I'm quite hard to please when it comes to cold synoptics so although the ECM shows an excellent trend in terms of the block being in place we don't want the pattern too far west.

 

It's better to see a chunk of the PV setting up in Scandi rather than moving sw towards the UK, it might look good on the charts but for longevity of cold its better to have a more eastern based negative NAO.

 

Hi Nick, surely we need a northerly at this time of year, what's the point of an easterly and 'eye candy' synoptics if the source is too mild, combined with the high North Sea SSTS ?

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Comparing the ECM 12z 120 hrs chart for Thursday with the 168 hrs chart from a couple of days ago reveals some big changes over the polar field with a much cleaner split in the vortex,and much more loaded onto our side of the hemisphere.

 

today..  2 days ago..

 

 

Its clear that the pattern is still evolving,and evolving in the right direction. :)

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Well all I can say is the ECM anomaly charts for T216 and T324 are not a million miles from NOAA and the GEFS. Slightly higher heights viv a vis Greenland at 216 and the trough in eastern Europe a tad further west at 324, which may or not be significant. Still resulting in low pressure in the eastern Atlantic and average temps over the run. The jet still running just south of the UK but tending further north later in the run but very weak.

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Agree with we need a northerly to set in for a while and then (early mid December) the beast can arrive! Not quite getting the bit about the vortex and being loaded to "our side "if the hemisphere!?! Yes agree it's a nice looking split and a huge improvement on last year if it progresses, however we are so vulnerable to so many variables it's still too far out for me.. 

Edited by phil nw.
snow cover in another thread
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Hi Nick, surely we need a northerly at this time of year, what's the point of an easterly and 'eye candy' synoptics if the source is too mild, combined with the high North Sea SSTS ?

You can still have a northerly with the pattern further east and troughing setting up over Scandi, an easterly I agree at this time isn't up too much. The reason I was critical of the ECM is that if the pattern gets edged too far west then the weak point of the block comes under attack from the sw.

 

I am happy however to see the ECM increase the blocking signal, tomorrows output may well be even better. I'm by no means trying to dampen the festive spirit in here the ECM is a very good output for the overall NH set up.

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I know I shouldn't keep doing these but what the heck!

 

Compare

 

 

Arguably the current ECM 10 day is synoptically the better chart.

 

steady purga - you'll get another 'popular' post.

 

going back to something nick s posted earlier, we see the 12z ecm correcting west wrt the previous run. it could carry on this way and we would end up west based -NAO. if you want my non ramping prediction, i'd say that we will see an almost textbook p/v split and surge sw of the cold. however, it wont make it this far as we will find ourselves too far south. perhaps the scots just taking a hit but not further south.  i would say that if this does happen, then its not a portent of near misses to come but merely a reflection how early in the season we are and that the wavelengths need to adjust more to allow us to get closer to any outpouring of arctic cold displaced by the neg AO.

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Hi Nick, surely we need a northerly at this time of year, what's the point of an easterly and 'eye candy' synoptics if the source is too mild, combined with the high North Sea SSTS ?

Hi Kimb, 

A Northerly is of use to members on North facing coasts due to the ```wish bone effect""" 

A northerly for inland areas are not much use unless there is a lot of unstable air comming in with it, look for kinks in the isobars for that if it evovles to verification  :rolleyes:

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Hi Kimb, 

A Northerly is of use to members on North facing coasts due to the ```wish bone effect""" 

A northerly for inland areas are not much use unless there is a lot of unstable air comming in with it, look for kinks in the isobars for that if it evovles to verification  :rolleyes:

A strong Northerly at this time of year with the warmer sea temps is exactly what we want, preferably a Northerly that varies to a North Westerly over to a North Easterly and then Easterly would suffice.

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