General Model Output Discussion

[karyo]

Could anybody explain why February will be mild? I am not disputing it, just need to see the reasoning behind this idea. I haven't followed the model output discussion thread recently and may have missed relevant posts.

Thanks

Karyo

Edited January 8, 2010 by karyo

[Liam J]

i think the models are unsure on how to evolve the situation at the moment, one model goes mild with an attack from the SW mainly the gfs through yesterday when the 12z run turned around from the 6z.

when the ecm was showing the cold hanging on and the ukmo also, yet today the gfs has gone back to the idea of the cold continuing further. and the ecm/ukmo going for a milder break down next week.

some of the minor models like the gem have kept the cold theme through next week, and until we see the models singing off the same song sheet we cannot be sure as to the outcome and the end of this cold spell.

since the current synoptic set up has not been seen for many many years for that reason i think the models over the next few days will throw out different scenarios until they grasp a continuing trend or pick up on the milder weather which is bound to happen sooner or later.

nothing is set in concrete yet, i wouldnt panic to much about losing your precious snow cover just yet, i feel many more fun and games to be had in the next 6 days or so.

Edited January 8, 2010 by james12

[nick sussex]

yeah me too!! why a mild Feb? I am still waiting for some snow here in Nottingham, as we have a MEASELY ONE & A HALF INCH. and seeing this being a very freak winter for the UK of recent years, Im scared my chances of some big snow are going to go away, and I will have to wait another 15-20 years for a similar event. I LOVE snow, and my hopes lie in Feb to produce since this Jan is really rubbish so far (snow-wise) for me!

Well the teleconnections suggest this but of course nothing is set in stone. To be honest if January continues cold by that time even the cold and snow lovers in here might welcome something a little warmer. Even if its milder that doesn't mean there won't be any short cold snaps.

That's a long way off though so lets just enjoy the current cold spell, it might not be perhaps the snowfest for yourself but for many people this will live long in the memory.

[Thundery wintry showers]

It is likely to turn milder for February because the teleconnections support the blocking getting a shift on, and pools of warm and cold air shifting around the Northern Hemisphere rather than sticking to certain areas (i.e. Eurasia)- or at least that was the latest I saw on it from Glacier Point and others.

Also, when we get this scenario with a Scandinavian High and no obvious sign of retrogression to Greenland, it usually ends (at least temporarily) with an attack finally succeeding from the south-west. A retrogression to Greenland is usually needed to keep the cold snowy weather going from here- the only other way it's likely to stay cold from here is cold and dry with high pressure, as happened for example around mid January 1982 and in late February 1979, and I don't think that scenario is very likely with the Atlantic powering up.

But note "milder" rather than necessarily "mild". I'm not convinced that once it turns milder it will stay that way for the rest of the season. We might still end up with north-west Europe often under the influence of cold pockets of air during February, especially if we get a stratospheric warming event, and if we do get cold spells during February there's a good chance of them being snowy.

[stewfox]

Could anybody explain why February will be mild? I am not disputing it, just need to see the reasoning behind this idea. I haven't followed the model output discussion thread recently and may have missed relevant posts.

Thanks

Karyo

Nobody knows on here what February will be like yet. It could be very very cold or average or very very mild. You could 'suggest' a trend at T240 but we are no where near T240 for Feb yet, beyond that even trends are FI.

Teleconnection towards the end of November still had most season forecasters predicating mild or average winter and/or a mild end to the year (JH). Looked what happened.

Check the November forcastes e.g SM 3rd week November (October prediction) has dry cold settled weather, we had exact opposite.

In fact the Met Office was still predicting a milder then average winter on 27^th November!

The best forecasting in the world can still only go to T168 and I would argue their 'trends' beyond that for a small Island like ours is often miles out

I.e. don't get too hung up on it or sell the shovel just yet.

Edited January 8, 2010 by stewfox

[karyo]

Thank you both for the responses.

I hope the models are overprogressive with trying to push away the cold too early! That was certainly the case with the December cold spell.

Karyo

[Coast]

I dont understand these charts and I am looking for guidance.

http://forum.netweather.tv/forum/69-learners-area/

[mrmonopoly]

http://forum.netweather.tv/forum/69-learners-area/

I understand those ones ok. What I am trying to say is thats confused me. Why is the breakdown occuring on the east side of the country or why does that seem to be the focus of the discussions.

[NorthNorfolkWeather]

I understand those ones ok. What I am trying to say is thats confused me. Why is the breakdown occuring on the east side of the country or why does that seem to be the focus of the discussions.

As a Welshman now living a long way from home, most of the focus being on the east at the moment because it ( the weather ) is coming from the East, which is relatively unusual.

The breakdown, when it comes WILL come from the south or South west, but the way things are, you are best going here and looking at the ensembles, after all Swansea is the second in the list (Abertawe), that will give you some idea on what is expected to happen in your neck of the woods.

[mrmonopoly]

As a Welshman now living a long way from home, most of the focus being on the east at the moment because it ( the weather ) is coming from the East, which is relatively unusual.

The breakdown, when it comes WILL come from the south or South west, but the way things are, you are best going here and looking at the ensembles, after all Swansea is the second in the list (Abertawe), that will give you some idea on what is expected to happen in your neck of the woods.

That looks intresting, it increases to just below zero you can see the semi break down then over the next 3 days it drops right back down again before a steady increase towards feb. IS that the classic reload scenario

[john w]

I do ind it interesting that each model has apparantly done a u-turn in the past 24 hours and i would suggest tentatively that the eventual outcome is likely to be something in the middle. agree with many that I think we will see milder conditions from mid next week here in the south but that milder in the ontext of today and averages will be something that is between well below average and average...i.e. still below average (but making events more marginal).

I note the meto have however in their languae at work trendedaway from 'less cold' discussions. The meto are also a little concerned that next week may herald some significant snow for some.

The max on the thermometer which i reset on Tuesday has not gone past 2 degrees and thaw here is limited. this cold spell will go down as one to be remembered.

[NorthNorfolkWeather]

That looks intresting, it increases to just below zero you can see the semi break down then over the next 3 days it drops right back down again before a steady increase towards feb. IS that the classic reload scenario

Personally, I wouldn't trust any model past 4 days (T96) at the moment. FI (Fantasy Island) is a moveable feast, and only when most of, or all, the models agree can you take FI out to as far as 8 Days (T192), and even then the detail will change.

So for the next 3 days, I'd say it will be slightly less cold, after that, I wouldn't trust the GFS ensembles as ECM goes in a totally different direction

I do ind it interesting that each model has apparantly done a u-turn in the past 24 hours and i would suggest tentatively that the eventual outcome is likely to be something in the middle. agree with many that I think we will see milder conditions from mid next week here in the south but that milder in the ontext of today and averages will be something that is between well below average and average...i.e. still below average (but making events more marginal).

I note the meto have however in their languae at work trended away from 'less cold' discussions. The meto are also a little concerned that next week may herald some significant snow for some.

The max on the thermometer which i reset on Tuesday has not gone past 2 degrees and thaw here is limited. this cold spell will go down as one to be remembered.

Good post, I think that the 'middle road' somewhere between the models is much more likely to be right. It's strange how the outputs have reversed for most of the models, we'll see some extra flips before this is finished.

The breakdown, when it comes is much more likely to produce a dump, followed by a thaw, rather than going out with a whimper. I cannot see milder air ending up over the whole country without some fairly heavy snowfall. If we get some wind in there, could be very interesting.

I personally STILL feel that we will not see much happen before late Thursday/Early Friday, and then we could see a lot

Edited January 8, 2010 by NorthNorfolkWeather

[len]

In the breakdown situations that are beginning to show in the models (Now that ECM has caught up with GFS)we always have lots of posts about how the "embedded" cold with resist (and perhaps even shrug off) these attacks.

Of course there is some obvious truth in this phenomenom, but I don't think it should be overated or become a straw to clutch at.

Have you ever thought that, if cold is so difficult to shift, we would never successfully get those WAA southerlies into Greenland that cause the height rises that create Greenie Highs.

You can't have it both ways, when we get an Arctic blast it's because the cold is being booted out somewhere else.

When the Jet (or the bigger synoptic picture) says shift, the cold shifts.

It may take 24 or 48 hours longer than computers say, but don't create false hopes.

Len

[snowking]

Big downgrade in precipitation on the 12z???

Not huge, slight - still a heavier pulse of precip running along and just to the north of the M4 on sunday, everything a little further south

The downgrade of precip, however, is due to the less pronounced warm sector and much lower dews and 850's

http://www.wetterzentrale.de/pics/Rmgfs848.gif

http://www.wetterzentrale.de/pics/Rmgfs842.gif

Compared to:

SK

[Eugene]

Coldest mild breakdown ever, surely

http://www.wetterzentrale.de/pics/Rtavn12617.png

Mild breakdown to temps around 0C

[nick sussex]

The ukmo looks very interesting so far upto 120hrs with some major snowfall but impossible to get an accurate track of the low at this stage. The key here is that the flow looks east to se ahead of the lows, lower dewpoints and drier air being pulled up from mainland Europe.

[Matt12]

It's hardly surprising people are skeptical about a 'so-called' mild breakdown given that it's still in F1: would anyone, for instance, take it as gospel if the charts showed a major snow event in F1? I think we'd all be rightly dubious until we were in closer to the actual event. Though, that doesn't mean it won't happen.

[Eugene]

Which mild breakdown is that matt, it doesn't exist on the three models runs tonight that have been released so far, GFS 12Z going for another cold two weeks just incredible. @O

The atlantic looks dead and blocking looks strong, can't see a change at all esp as we enter Feb traditionally one of the quietest months of the year.

[sandstorm2]

I had resigned myself to some sort of less cold weather in a weeks time but the models are now showing tonight, that this cold looks like going on and on! Parts of northern spain look like taking a beating too.

SS2

[Tom D]

The GFS is quite scary with no end to the block and thus remaining cold - if not snowy or as cold as recently then very chilly and below average. UKMO is very similar up to 144 pushing the first low below the block, potential snow event in England and Wales.

It's only one run, the ensembles are churning out now so interesting to see how the operational stands amongst the other runs.

ECM strongly hinted at an end to the block earlier, will it be very different this evening?

[Snowly does it]

For trend spotters, the following should be watched for as they are now recurring on GFS operationals and are a good guide to what we might expect.

On Tuesday of next week, an area of LP attacking into the SW but making very minor inroads and dropping snow along a to-be-determined line en route.

This is pushed through under cutting the sagging Scandi HP which holds on over S Norway/Sweden at 1025-1030mb propped by the sliding LPs

The LP pushing through drags an Easterly or ESE flow back across us and -5s or thereabouts drop back in

Azores High throws up a tenative ridge to the West of Ireland which may be of future benefit

Deeper FI - signs of a renewed HP rise to the NE and perhaps the NW

At best for 'milder' weather the GFS suggests the South coast may struggle up to around average for a day or two next week as the LP slide under us

[igloo]

I had resigned myself to some sort of less cold weather in a weeks time but the models are now showing tonight, that this cold looks like going on and on! Parts of northern spain look like taking a beating too.

SS2

[/quote

seriously stop looking at the charts after +168 they are pointless stupid infact

[nick sussex]

The GFS is quite scary with no end to the block and thus remaining cold - if not snowy or as cold as recently then very chilly and below average. UKMO is very similar up to 144 pushing the first low below the block, potential snow event in England and Wales.

It's only one run, the ensembles are churning out now so interesting to see how the operational stands amongst the other runs.

ECM strongly hinted at an end to the block earlier, will it be very different this evening?

Given the trend so far this evening i think we're seeing the models pull back from a complete breakdown and there are some possible major snow events for areas lucky or as the case maybe unlucky on the northern flank of those lows. I wonder if this continues well into January whether even cold and snow lovers might want something less cold.

As much as we all love the cold and snow just how much could the UK take!

[Shiny_Bottom_1]

For trend spotters, the following should be watched for as they are now recurring on GFS operationals and are a good guide to what we might expect.

On Tuesday of next week, an area of LP attacking into the SW but making very minor inroads and dropping snow along a to-be-determined line en route.

This is pushed through under cutting the sagging Scandi HP which holds on over S Norway/Sweden at 1025-1030mb propped by the sliding LPs

The LP pushing through drags an Easterly or ESE flow back across us and -5s or thereabouts drop back in

Azores High throws up a tenative ridge to the West of Ireland which may be of future benefit

Deeper FI - signs of a renewed HP rise to the NE and perhaps the NW

At best for 'milder' weather the GFS suggests the South coast may struggle up to around average for a day or two next week as the LP slide under us

Very much in line with my thoughts from this morning SM.

HAven't seen the 12z ensembles, but a cold weather continuing looks like a good bet at the moment.

When looking at the charts, its quite clear how cold much of Europe is, including France, so even a flow from this direction looks chilly.

seriously stop looking at the charts after +168 they are pointless stupid infact

Come on. Model discussion. Models go out to T+384, so people are entitled to post such things.

[Iceberg]

The GFS really is failing to push the Atlantic in, isn't it. Same kind of dogs dinner as the last few runs in reality, the best that can be said is that it fails, no matter how it might try to introduce any kind of average weather.

There are a few days where DP's rise above freezing, but you can count them on one hand for the next 15 days.

The lows deliver snow away from Cornwall even on METO.

ECM is really going to be interesting tonight.