Model Output Discussion

[Cecil Hogmanay Melchett]

Worth pointing out kold the runs last week were going for atlantic domination this week which is far from the reality with just one front coming through west to east, just late last week most on here were very confident of atlantic westerlies taking over, go back to earlier models threads and see for yourself.

http://www.wetterzentrale.de/pics/Rtavn1441.png

Yes your correct Eugene,i got it very wrong and swallowed the Atlantic dominated outputs only 48 hours ago.I notice that others who got it very wrong are strangely missing since Saturday.

I guess the conclusion is the models are very unreliable at 96 hours and longer.

Kudos to TEITS and Nick Sussex and others who remained open minded and objective when others inc myself were trumpetting the Atlantic and basically dismissing the Siberian High.

Exciting times.

:lol:

[phil nw.]

The runs ,so far, showing some sort of East or South Easterly flow by Monday.

This showed on yesterday`s 12z ECM and now all the others are going for it.

It will be cold at the surface regardless of whether we get the colder uppers from the East.

At the moment it looks a fairly dry few days after the last front goes through on Friday and pressure then starts to rise.

It would be typical if the ECM showed something else now but looking at this mornings ens. i would be suprised,

http://www.meteogrou...-tt6-london.gif

It`s just a case of where the High will finally settle now as to whether we get renewed cold uppers from the East.

At the moment i would favour something more South East,but as i say still cold.

[MR EXTREMES]

i think the models are really stuck its a very difficult setup to call.

i was going mild alantic it seems im wrong about that one but still feel the alantic will break through in time.

but for now i dont see nothing to be over excited about although cooler nothing extreme and because of this snowfall will be very small,

i expect a cool quiet cloudy conditions as kold suggested and as nick sussex explained really theres no point with running away with the idear deep cold will be back,

although more runs are needed and its possible deep cold could come back,

but the block if anything is making it hard for anything exciting to happen thats why im skeptical of nearly every single run.

but all the same its intresting to see how this develops:drinks:

[shuggee]

Worth pointing out kold the runs last week were going for atlantic domination this week which is far from the reality with just one front coming through west to east, just late last week most on here were very confident of atlantic westerlies taking over, go back to earlier models threads and see for yourself.

http://www.wetterzen...s/Rtavn1441.png

Were they?

Today's 12Z GFS T+24:

And last Thursday's 12Z GFS T+144:

Of course, if folk insist on looking beyond anything like the reliable timeframe then of course it's going to chop and change all of the time. That's why anything past T+144 should be taken with the largest pinch of salt and it's quite disingenuous to be forever saying how 'the models are struggling' etc etc when actually they are performing within normal parameters as indeed the model verification stats at 6 days continue to show...

[kold weather]

Worth pointing out kold the runs last week were going for atlantic domination this week which is far from the reality with just one front coming through west to east, just late last week most on here were very confident of atlantic westerlies taking over, go back to earlier models threads and see for yourself.

http://www.wetterzen...s/Rtavn1441.png

Whenever you need the jet and the PV to be in perfect locations to just about force away any block, you can pretty much be certain that once either part of the duo eases off the block will head back west again. In this case we don't really get into the Scandi high set-up on the models till 144-168hrs and instead what we are under is an increasingly displaced Azores high thats tilted in such a way by the stronger high to its NE which allows what will be a bitter drag from the ESE in.

This could allow in a brief colder shot, and IF the block holds close enough to the UK in the longer term then the pattern could evolve eventually similar to Feb 91...but any such evolution is VERY long winded, we are talking 10-15 days once we have the block in place.

Still I've said time and time again, the models very often do under-estimate blocks, indeed I've seen cases where the ridge is 300% stronger then progged...at just 12hrs!!!

[MR EXTREMES]

of coarse shugee i understand what your saying its all still fi.:lol:

[Frosty.]

Anyway, in the short term the atlantic will win as fronts move east on thursday and friday with only rain forecast and milder air following into the west but still feeling chilly in the persistent rain and strong winds in the east on friday. We are then looking for the changes to commence over the weekend which will hopefully set us up for a cold spell next week which hopefully the ecm will stick with.

[Ben_Cambs]

Anyway, in the short term the atlantic will win as fronts move east on thursday and friday with only rain forecast and milder air following into the west but still feeling chilly in the persistent rain and strong winds in the east on friday. We are then looking for the changes to commence over the weekend which will hopefully set us up for a cold spell next week which hopefully the ecm will stick with.

ECM 12z T+96:

[cooling climate]

ECM at t96 and a much better orientation of the high compared to the

12 GFS run. I may well be jumping the gun but this could be a very good

run.

Scrap that.

[Cheese Rice]

i think the models are really stuck its a very difficult setup to call.

i was going mild alantic it seems im wrong about that one but still feel the alantic will break through in time.

but for now i dont see nothing to be over excited about although cooler nothing extreme and because of this snowfall will be very small,

i expect a cool quiet cloudy conditions as kold suggested and as nick sussex explained really theres no point with running away with the idear deep cold will be back,

although more runs are needed and its possible deep cold could come back,

but the block if anything is making it hard for anything exciting to happen thats why im skeptical of nearly every single run.

but all the same its intresting to see how this develops:drinks:

I'm thinking something similar to Jan 2009, the continent will be very cold and with winds coming from the south east we would see the cold surface air spreading across the country. I wouldn't be surprised if many ended up with sub-zero daytime temps and night temps down to -10c to -15.c. Coupled with freezing fog we could be looking at a very cold spell even though on the face of it, it doesn't look that cold.

[MR EXTREMES]

ECM at t96 and a much better orientation of the high compared to the

12 GFS run. I may well be jumping the gun but this could be a very good

run.

looks to me its retreating.

[Cloud 10]

FWIW,the nogaps 12z is aboard the easterly express.:lol:

[SP1986]

looks to me its retreating.

Hard to tell, it is in a better position if it can ridge north, but it's difficult to tell at the moment, at that point though it feeds in a light westerly, but it's all very close. I suppose whatever happens under this pattern evolution, cold is 60/40 in favour to win.

I think eventually it will have to ridge north and east bringing at least a short inversion condition.

I suppose the signals are really causing a headache in the models as Ian Brown alluded to a few days ago.

re: NGP, if were fair we can write that off, it can be fairly stable as a model but it tends to be wrong in the first place :lol: (usually)

[Ben_Cambs]

FWIW,the nogaps 12z is aboard the easterly express.:lol:

Thats one massive change from NOGAPS 00z, which had no Easterly at all! Shows how much all the models major and minor are changing at the moment!

[cooling climate]

Yes I think I jumped the gun there. It looked better on the northern hemisphere charts

but when I viewed it on the European it didn't look that great.

[Ben_Cambs]

The very cold uppers not far away at all on GEM 12z at 144 hours:

[Matty M]

ECM slows things abit as compared to the UKM.

Impressive height rises to our north.

ECM not as impressive as some would like.

I think the main difference between the ECM and UKM is that it allows that low to push towards us at around 120hrs thus

setting back the block moving in from the east.

[SP1986]

After seeing the GFS evolution being perhaps the wrong side of trustworthy, I now think the evolution on the ECM is not something I can see happening, I think the transfer eastwards of the high bringing in the Atlantic is a bit progressive for my liking.

I think the secret as some have said is that FI is something like 96 hours right now.

[cooling climate]

Well the 12z ECM run has quelled the excitement somewhat I would have imagined.

Everything still up in the air I would say as regards to next week.

Again the ensembles will give us a better idea, roll on 21.15.

[Guest North Sea Snow Convection]

One difference between now and the New Year period is that we have lost the -NAO signal. This was helping to retrogress high pressure westwards. There are signs of Azores High pressure on all of the models, plus more energy further north instead of the undercutting lows we have seen previously. That is going to make things harder to back the cold west - hence why it is just possible that the coldest upper air might not get far enough to us.

A dry easterly is looking fairly likely, at least for a while, which would certainly be cold at the surface, but I think potential for snow is less now than it was during the last cold spell.

[MR EXTREMES]

The models are agreeing on some sort of HIgh to the East, it doesn't look to be of high enough latitude to bring a cold AND snowy easterly and I would think it unlikely to evolve into such a situation.

However looking at the output tonight and the general way the Atlantic is looking held, this easterly of sorts looks much more likely to occur than the one being progged a few days back.

i think thats what i was thinking the general position of the high is not very favourable on some models.

but its trying to push cold our way.

i think a nice striaght easterly or even a north easterly is that azores high trying to drift nw aswell?

i think last winter was dominated by heights in the alantic and cold feeding from greenland and the arctic,

perhapes not ideal for all but was pretty snowy in some parts,

although this is not likely right now with activity there in the alantic im just intrested to see where the azores h ends up i expect it will just sink south again.

still just goes to show how intresting this winter is with easterly flow trying to dominate incredible really.

[nick sussex]

The model merry go round continues with the ECM pulling out a rather bizarre looking run. It throws a piece of energy eastwards off the main trough at 120hrs then eventually struggles to a slack easterly flow and then sinks the high but then decides to not sink it completely by keeping low pressure in the Med. I think the GEM is actually a little similar earlier on but then is quicker to get to the easterly.

I think we can see now why i was worried about the 120 to 144 hrs timeframe! I'm afraid the uncertainty continues.

[Snowyowl9]

I would think the next cold spell if it comes off will be a very much dryer one to the last with lots of frost more like last January.

We have seen alot of snow this winter so can`t complain.

ECM shows alot of blocking going on.

[Guest North Sea Snow Convection]

I would think the next cold spell if it comes off will be a very much dryer one to the last with lots of frost more like last January.

We have seen alot of snow this winter so can`t complain.

ECM shows alot of blocking going on.

As great as snow is, I must say that cold, crisp weather with plenty of frost and winter sunshine would be prefectly acceptable to me. Quiet High pressure is quite welcomed by me - we haven't seen much of it this winter at all

As you say, we can't complain in terms of the large amounts of snow we have already seen.

[MR EXTREMES]

The model merry go round continues with the ECM pulling out a rather bizarre looking run. It throws a piece of energy eastwards off the main trough at 120hrs then eventually struggles to a slack easterly flow and then sinks the high but then decides to not sink it completely by keeping low pressure in the Med. I think the GEM is actually a little similar earlier on but then is quicker to get to the easterly.

I think we can see now why i was worried about the 120 to 144 hrs timeframe! I'm afraid the uncertainty continues.

yes i agree its crazy stuff i think the mjo is on the move lots going on with el nino ive even herd talk that its weakening i think the neg nao losing its grip is very likely to throw teleconnection in the air im not so sure what the ao is doing.

but im now even more certain we are going to be in a tug of war situation,

but never to unsettled i dont think blowtorch,

i dont think very cold either just average or slightly below but snowfall very very limited if any.

where stuck in a rut lol.