[Model Output Discussion 01/09/17]

41 minutes ago, karlos1983 said:

Question while it’s quiet if I may. can Volcanic eruptions have any impact on weather models?

Didn't that volcano in Iceland (with the funny name) erupt in 2009, which consequentely grounded a lot of flights because of the air bourne ash? 

Further to that, sunspots were low too, so I wonder if there's a link with an inactive Sun > active volcanoes > northern blocking and cold winters for north west europe?

Could it be volcano eruptions and their repercussions cause chaos with the models, such as we've seen recently?

[Model Output Discussions 06z 04/11/16]

4 hours ago, Minus 10 said:

Arctic floodgates once again! LOL

Once again, something being sniffed out for next weekend....

[Model Output Discussion - 10th Jan Onwards]

Maybe some hope in Ian's recent comments re MOGREPS - If I remember correctly MORGREPS  was a big factor in the METO not backing the failed Easterly forecast last week, for this week?

 

Also, regarding the high level of 'shannon entropy' could this also be a positive thing? I've heard it time and time again that the models struggle with reverse zonality/NE blocks, but are very good with zonal/Atlantic driven weather, so the fact they cannot forecast with high confidence what they are 'good at' suggests to me that Atlantic driven weather is less likely?

[Model Output Discussion 17th Dec.2013-12z onwards.]

I'm still not seeing the doom and gloom for January, sorry.

 

We already knew w e were locked in zonal for December, all that has changed is that the more favourable conditions for blocking as we end the month are manifesting themselves in the output - mainly in the ensembles but not exclusively so.

Now this doesn't mean HLB and a strong cold signal should appear in the same timeframe and I wouldn't expect ECM ensembles to show anything other than Ian F describes because within the 15 day timeframe any blocking is very unlikely to establish itself to the extent of bringing a cold spell and even decent blocking that is forming within those ensembles may well show a Westerly flow and moderate or even mild temperatures. Forget ECM32, or at least take its long range output with a pinch of salt, it is just going with the favourite instead of looking at the form guide.

 

The fact is there will be a window of opportunity for blocking to grab a foothold as the jet moves South with low pressure moving into Central Europe out to the mid term and what is considered reasonable reliable timeframe of the output (around 144) at the same time we have pressure rising on the other side of the pole - I will use the latest GFS 06z output to illustrate.

 

Mid term, Southerly jet, low pressure (trough) pushes South into Europe

 

 

From here a lot will depend on how much energy is forced NE over the ridge to our East and how fast and flat the next low pressure system is to our West. Too fast and flat and then the PV and mobile theme will likely override any blocking signal but  a slower pattern behind with the next low not quite so deep will likely keep the pattern amplified - see yesterdays GFS 12z (before it updates today) against the flatter faster ECM this morning.

 

 

Now Nik Sussex has already called fail on yesterdays 12z but it isn't a done deal yet IMO because there is still a signal for a slower pattern behind within GFS ensembles and GEM is still showing this today.

 

 

Even if we take a blended solution the pattern will still be more favourable for blocking going into January proper.

 

We can look at GEM at day 10 and on face value it would show an unsettled Westerly regime but look how much more favourable the pattern is for possible future developments with an almost split vortex. Now this maybe on the optimistic side of the output but ECM is on the pessimistic side IMO and even then it looks like a more amplified pattern would develop again from day 10.

 

 

 

 

 

We already knew we were playing the long game so I'm not sure how the output is so disappointing for January prospects, I just don't see it. I see increased blocking opportunities toward the end of December and through the first week of January (these will unlikely show up as cold runs even where blocking is gaining a foothold) and I do think we have a reasonable shot of a cold spell developing for the second week of Jan with prospects increasing for further blocking from there no matter what EC32 output is.

 

If we end up with a flat zonal pattern at the end of December/ start of January, I will feel very differently but I just don't see that as written in stone at the moment.

I'm not saying it will be cold and snowy second week of January (no hopecasting)- even if we got a decent block set up there is no guarantee we will be on the right side of it. All I am saying is let's not go writing January off on the basis of the current output and the EC32.Even when things look bad we can only realistically write off cold prospects for 14 days max and the output really isn't that bad and the improvements in the output over the last few days seem to have been largely overlooked because the broad theme will remain the same.

 

Granted a lot will depend from developments around the 26th Dec (I pick the 26th arbitrarily because that is when low pressure pushes South into Europe and we are on the edge of reliable output) and it may well turn out we are staring down the barrel again come the end of December but I'm just trying to give an opposite (optimistic) view of how the output may turn more favourable in January.

 

For a total novice like me, this is such a great post - explained clearly with not too much techno-jargon, the balance of optimism and realism I like a lot too.

 

Much to my wife's annoyance I have spent far too much time on here the last couple of months, even though not a lot has been going on from a cold/snowy perspective. However things seem to be slowly falling into place - during the remainder of December perhaps we're going to see the start of something 'juicy'! I really hope so...

[Model Output Discussion - 30th November onwards]

Maybe GFS coming up with a major Scandi block is going to become a bit of a trend.... which it will later drop, as the ECM starts to sniff around it?

[Model Output Discussion 18th Nov.2013-12z onwards.]

Anyone downbeat about what December will bring only needs to cast their mind back to the end of October and the talk of a mild November.

 

Things can change, there's hope...

[Winter Model Discussion 18Z 12/2/13 onwards.]

So… Once again the ECM is showing some real eye candy in FI and quite rightly there are a lot of people trying to not get too excited after the 'watering down' of the other great charts shown earlier this year. Now, although there's no doubt it would be an unforgetable end to Winter if anything like these charts were to verify, lets be realistic - if the almost expected watering down does happen and we end up with something similar to the last two 'cold snaps' of this year, that's not all bad is it? Especially when you consider only a few days ago Winter was apparantly over.

I think it's true, after the Winter 09/10 people's expectations are a lot higher. And as many have said if someone you were offered you what we've had this winter during the 2000s you would have bitten their hand off!! Let's be grateful for what we've had and of course keep our fingers crossed for Winter giving us a good kick in the balls before it says farewell!!!

[Winter Model Output Discussion - 06Z 09/02/13 onwards]

Since finding this forum, specifically this particular thread not a day goes by without me spending considerable time reading it. Great content, great people - keep it up!

I have to say I find it mildly amusing how until this morning a lot of people were critisising the GFS, saying how it should be ignored etc. But now it is showing potential for a possible sting in Winter's tail people's attitude towards it have changed massively!

Now, my level of understanding is beyond basic but one of the small pieces of information I recall is the theory that the GFS handles developments on the US eastern seaboard better then the euros - if true, perhaps this increases that glimmer of light that started shining at 06z and maybe just maybe we could well see decent heights over GL before Winter is done with us?

Apologies if I'm talking out my backside, as said I am a complete newbie to all this weather lark!

[Winter Model Discussion - 11/01/13 00z Onwards]

Good Morning! First post for me, since our winters 'turned cold' or at least cooler a few years ago my interest in the weather has really taken off. Upon hearing all about this SSW event I found this site, more precisely this thread. Amazingly interesting watching things unfold, the twists and turns in the models and learning bucket loads along the way.

I have to say though my wife isn't too pleased with my addiction to this forum!

Anyway back to the models - my knowledge is extremly limited however with the ECM appearing to be going cold (warm) on us coldies and the GFS starting to improve prospects, it almost looks to me that when looking forward at 96+ (to my untrained eyes) that the ECM is lagging behind the GFS? What I mean is with all the GFS/ECM each taking turns to a coldies's favourite' could it be that the GFS is ever so slightly ahead of the ECM with it's thinking and by the time the ECM has caught up, it has moved onto another outcome? Seems to be the general pattern and goes a little way to explaining the sometimes huges disagreement between the two models?

Apologies if I'm talking complete crap!

Great forum - even better now admin has clamped down on all the 'chit chat'