Model Output Discussion; into 2015

[IDO]

  MattHugo81

@chionomaniac - Just looked through 00Z EC Clusters and not a whiff of any N blocking yet it's a zonal +AO & esp +NAO pattern throughout.

29/12/2014 09:22

 

^^^Despite the warming in the strat the ECM trop output shows no sign of a quick response. The GEFS are also similar apart from the odd one. Caution on the strat thread as well as wave 2 warming is probably not ideal for a full SSW (at the moment): https://forum.netweather.tv/topic/81567-stratosphere-temperature-watch-20142015/page-48

 

Even with very good warming events it does appear that the strat to trop relationship is never as straight forward as you hope.

 

ECM, GEM and GFS mean at D10:

 

   

 

As expected good agreement.

[MPG]

  MattHugo81

@chionomaniac - Just looked through 00Z EC Clusters and not a whiff of any N blocking yet it's a zonal +AO & esp +NAO pattern throughout.

29/12/2014 09:22

 

^^^Despite the warming in the strat the ECM trop output shows no sign of a quick response. The GEFS are also similar apart from the odd one. Caution on the strat thread as well as wave 2 warming is probably not ideal for a full SSW (at the moment): https://forum.netweather.tv/topic/81567-stratosphere-temperature-watch-20142015/page-48

 

Even with very good warming events it does appear that the strat to trop relationship is never as straight forward as you hope.

 

ECM, GEM and GFS mean at D10:

 

gens-21-1-240 (3).png gens-21-1-240 (2).png EDM1-240 (3).gif

 

As expected good agreement.

 

Must admit that's a very level headed post from IDO. 

[Summer Sun]

A pretty poor ecm ens again for colder prospects the 850's

 

NYD starts with a sw'ly flow

 

 

That then swings round to a west to north westerly

 

 

Then its a westerly till then end

 

 

This is the coldest the 850's get

 

 

Beyond this its nothing worse than -3 once those colder 850's clear

 

[bluearmy]

I wouldn't be counting any stratospheric chickens based on the extended ECM ens. They do go to the very top of the strat and should provide good guidance as to any potential quick response in the trop to events up there. However, we are looking at a potential SSW but it wouldn't happen within the next 12 days, and perhaps a few more thereafter. I guess to see no response in trop output which goes to two weeks shouldn't be a surprise.

What was encouraging to see recently, was an apparent mirroring between the trop long wave pattern and the upper strat . that appears to have waned as we see a slight disconnect in the upper strat between events 10hpa/50hpa. IF, the upper strat modelling by ECM op is correct, we can expect to see some stellar output for mid January beginning to show and that should be initially on the extended ECM clusters, hopefully followed by gfsp (which looks like it may be starting to whiff the same coffee as ECM ).

So I would be looking at the gfsp NH profile on 10hpa strat to see if it mimics the ECM temps (stronger warming Greenland area compared to Asia) and then watch if there is any trop response in the 12/14 day timeframe. you have to look at the NH profile to monitor this.

[The Weather Watcher]

  MattHugo81

@chionomaniac - Just looked through 00Z EC Clusters and not a whiff of any N blocking yet it's a zonal +AO & esp +NAO pattern throughout.

29/12/2014 09:22

 

^^^Despite the warming in the strat the ECM trop output shows no sign of a quick response. The GEFS are also similar apart from the odd one. Caution on the strat thread as well as wave 2 warming is probably not ideal for a full SSW (at the moment): https://forum.netweather.tv/topic/81567-stratosphere-temperature-watch-20142015/page-48

 

Even with very good warming events it does appear that the strat to trop relationship is never as straight forward as you hope.

 

ECM, GEM and GFS mean at D10:

 

gens-21-1-240 (3).png gens-21-1-240 (2).png EDM1-240 (3).gif

 

As expected good agreement.

 

 

 

Well, the strat to trop relationship wasn't always 100% but it's still early to be expecting Split Vortices and HLB forecasted in abundance. The models don't look promising, but that can change very quickly.

[mulzy]

As eluded to above, the NWP is poor for sustained wintry conditions.  The ECM ensembles for De Bilt are pretty ordinary (as far as wintry weather is concerned)

 

 

Not surprising when you consider the NAO and AO are expected to go significantly positive in the medium term.

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.sprd2.gif

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.sprd2.gif

 

However, we know that the NWP can flip so I guess patience is required.

[Yarmy]

  MattHugo81

@chionomaniac - Just looked through 00Z EC Clusters and not a whiff of any N blocking yet it's a zonal +AO & esp +NAO pattern throughout.

29/12/2014 09:22

 

^^^Despite the warming in the strat the ECM trop output shows no sign of a quick response. The GEFS are also similar apart from the odd one. Caution on the strat thread as well as wave 2 warming is probably not ideal for a full SSW (at the moment): https://forum.netweather.tv/topic/81567-stratosphere-temperature-watch-20142015/page-48

 

Even with very good warming events it does appear that the strat to trop relationship is never as straight forward as you hope.

 

ECM, GEM and GFS mean at D10:

 

gens-21-1-240 (3).png gens-21-1-240 (2).png EDM1-240 (3).gif

 

As expected good agreement.

 

 

Solid consistency there, so it would be very surprising if it panned out differently in the short to medium term.

 

Re:Matt's tweet on the EC clusters. There was a point in mid-December when all 51 members pointed to a mild SW flow for Christmas Day. As ever, time will tell.

[IDO]

Well, the strat to trop relationship wasn't always 100% but it's still early to be expecting Split Vortices and HLB forecasted in abundance. The models don't look promising, but that can change very quickly.

 

 

No I only mentioned it as there had been good coupling strat - trop lately. Is it not typical that there is a good connect when zonality is forecast but when the trop is showing a split there is a time lapse

[kev238]

It seems pretty clear the pattern for the next 10 days or so is set.

What needs to be remembered is that it did not take especially outstanding charts to deliver a notable snowfall to central parts - albeit a pretty limited zone. Therefore, this hunt for -10 uppers blowing from East is not necessary to product snowfall.

[karyo]

We have seen this before, the models showing frequent incursions of polar maritime air with wintriness even at lower levels but as we approach the T0, those incursions move further and further norts and in the end we end up with average or even mild weather. This is because the models have the tendency to overdo the extend of those incursions. 

 

Like other posters have already said, tropospherically, there is nothing promising in the models today. 

[bluearmy]

No I only mentioned it as there had been good coupling strat - trop lately. Is it not typical that there is a good connect when zonality is forecast but when the trop is showing a split there is a time lapse

 

but the upcoming arctic ridge splitting of the trop vortex shows strat then trop within a 24/48 hour timeframe ? that seems quite quick to me IDO. thats why i believe that any reversal high up will propogate effecively.

[karlos1983]

I think patience is the key for the turn of the year. It is fairly clear for all to see that we will be influenced now by a predominately Westerly flow with some PM incursions, on a personal note, never really any good for my neck of the woods, just cold and wet as opposed to warm and wet/windy.

 

But with what is going on in the Strat, things can change pretty quickly. It will be tough viewing the Models for the next 10 days at least IMO, but reading between the lines, as we enter the second part of January the general feeling is things could well change pretty quickly. Or at least I hope it will, as I'm not sure how many more attempts we will get away with for deep cold to produce for the UK as a whole. Couple of years ago the north got battered with snow, whilst the south missed out all together, as we head into the later stages of winter it becomes increasingly difficult to get deep cold this far south from past experiences.

 

Here's to a cracking New Year    hopefully

[IDO]

hi

I have missed them but would be grateful to see them if anyone can give me a link please?

 

Hi John. Re ECM bias

 

My findings are that ECM are far better within an ongoing pattern up to D10 and that is why verification is better than GFS. The later's bias with the Atlantic means it will always trail the ECM in a static pattern. However it is when there is a pattern change, be it mid-lat lows or a build up of heights the ECM fails. They have a strong height bias in the early days of an upcoming pattern change. This current "block" is a case in point, where ECM built Scandi and Greenland Highs, over estimating the pattern change.

 

We can see from the D6 verification stats, the period of 26th is just showing up: 

 

The average for D6 is 0.85 (31 days) but the last two runs show 0.65 and 0.58. They coincide with the uncertainty re the sinking Atlantic high. ECM will nearly always fail through over blowing heights. We would expect some loss of verification due to the synoptic change, but ECM was only worsened by GEM, who are even worse at over blowing heights!

 

Of course models are most needed when pattern changes are forecast, as that is when forecasters' need the most help, so ECM's bias does lead to some very exciting winter charts as the early bias feeds into the D8-10 charts. They rarely verify and hence the disappointment with the ECM performance.

 

Only in my opinion.

Edited December 29, 2014 by i'm dreaming of...

[IDO]

Interesting GFS op: 

 

Good warming but still not quite a split by D16:

 

  At 30mb: 

 

Apart from that little change on the GFS 06z op for our sector. Zonal right out till D16. However on a NH perspective the op rebuilds the Alaskan ridge in its later stages:

 

[blizzard81]

Hi John. Re ECM bias

 

My findings are that ECM are far better within an ongoing pattern up to D10 and that is why verification is better than GFS. The later's bias with the Atlantic means it will always trail the ECM in a static pattern. However it is when there is a pattern change, be it mid-lat lows or a build up of heights the ECM fails. They have a strong height bias in the early days of an upcoming pattern change. This current "block" is a case in point, where ECM built Scandi and Greenland Highs, over estimating the pattern change.

 

We can see from the D6 verification stats, the period of 26th is just showing up: cor_day6_HGT_P500_G2NHX.png

 

The average for D6 is 0.85 (31 days) but the last two runs show 0.65 and 0.58. They coincide with the uncertainty re the sinking Atlantic high. ECM will nearly always fail through over blowing heights. We would expect some loss of verification due to the synoptic change, but ECM was only worsened by GEM, who are even worse at over blowing heights!

 

Of course models are most needed when pattern changes are forecast, as that is when forecasters' need the most help, so ECM's bias does lead to some very exciting winter charts as the early bias feeds into the D8-10 charts. They rarely verify and hence the disappointment with the ECM performance.

 

Only in my opinion.

Thank you IDO. This is what I was trying to get across to the forum last night. Some members had a terrible reaction to it but you have explained it very well indeed. Back to the modelling of today and I must agree with some of the comments with regards to cool/cold zonality being over cooked by the models. It's as if the models under estimate heights over Europe so that as we run down the clock, pressure is higher over Europe than was originally modelled. As a result, we get more TM air as opposed to PM air.

[John Snow]

as we head into the later stages of winter it becomes increasingly difficult to get deep cold this far south from past experiences.

 

Here's to a cracking New Year    hopefully

Feb 2009 I got 16" of snow from a Thames streamer, anything is possible, feb 2009 was as a result of an SSW event too so there is still everything to play for

[Stormyking]

People may think im crazy but as a neutral weather enthusiast , I love all this chop and changing with the charts, be it showing mild or cold.

 

Anyways, Next couple of days, nice ridge of high pressure over the UK to give some lovely sunny days and harsh frosts at night, I for one am not complaining! Coldest bit of weather in 2 years! 

 

Nice crisp frosty weather with this chart

 

All change as we head into the weekend, with some weather fronts bringing some more wetter weather, which i dont mind at all either!

 

Things look to be going really unsettled for a time by the looks of it as time goes on, but after this weekend i think is all up in the air, so im not worried about anything, still not even in January yet!

 

This would be rather nasty though :O

[Polar Maritime]

Ok lets continue with polite and respectful discussion please.

Thanks.

[EML Network]

Since there's very little in the way of any decent cold weather on the horizon for the next few weeks (it would seem), my attention is now being drawn to some of the extreme wind speeds that the GFS has been churning out run after run post 192 over the past 4 or 5 days. 

 

To kick off the GFS Op for Thursday afternoon +81 shows a large part of Northen England and Scotland with Max gusts of up to 70 Mph

 

 

WAY in FI but run after run, the 6-11th Jan shows some really stormy outputs, this one the GFS Op for the 9th, showing a system that runs across the SE of the UK, IF this came off as shown then it's batten down the hatches time.

The same ''Storm'' exiting the UK

Sticking with the OP, and the output showing a windy day for everyone on the 11th Jan...

 

That's JUST the Op run, let's delve into the Parallel to see if there's ANY support or if any of the dates coincide..

 

No surprise to see Thursdays wind speeds there, but slightly further south and not quite as strong as the Op, still Max gusts 65 Mph are not to be sniffed at and covering a large area of the UK...

 

.

 

 

The Parallel wants things to get quite windy on Saturday too, getting close to 60 Mph across the South. 

The Parallel then has a small part of NW Scotland getting absolutely battered on Monday the 5th, although they're used to it up there

Just 2 days later and on the 6th Jan the Parallel has almost every part of the UK experiencing wind gusts of between 50-75 Mph 

THE VERY NEXT DAY...7TH JAN !

10TH Jan.again on the Parallel....

 

 

The Parallel is one of the stormiest runs I have ever seen with day after day after day of extremely high winds and presumably copious amounts of rainfall. 

 

FINALLY, looking at the control run for a 3rd and final comparison , looking solely at the pressure charts fr the periods 7-11th Jan...

 

Here's the 7th Jan, looking pretty windy to me

and the 10th Jan again looks very stormy

 

If it wasn't the fact that this is about the 5th or 6th day in a row that the time period 6-11th January is showing up as very stormy on the GFS runs, I wouldn't have bothered posting these charts, but if the trend starts to firm up over the next 7 days then IMO the wind and rain will be getting the headlines and the cold will be taken off people's minds for a short while at least

Edited December 29, 2014 by EML Network

[johnholmes]

Hi John. Re ECM bias

 

My findings are that ECM are far better within an ongoing pattern up to D10 and that is why verification is better than GFS. The later's bias with the Atlantic means it will always trail the ECM in a static pattern. However it is when there is a pattern change, be it mid-lat lows or a build up of heights the ECM fails. They have a strong height bias in the early days of an upcoming pattern change. This current "block" is a case in point, where ECM built Scandi and Greenland Highs, over estimating the pattern change.

 

We can see from the D6 verification stats, the period of 26th is just showing up: cor_day6_HGT_P500_G2NHX.png

 

The average for D6 is 0.85 (31 days) but the last two runs show 0.65 and 0.58. They coincide with the uncertainty re the sinking Atlantic high. ECM will nearly always fail through over blowing heights. We would expect some loss of verification due to the synoptic change, but ECM was only worsened by GEM, who are even worse at over blowing heights!

 

Of course models are most needed when pattern changes are forecast, as that is when forecasters' need the most help, so ECM's bias does lead to some very exciting winter charts as the early bias feeds into the D8-10 charts. They rarely verify and hence the disappointment with the ECM performance.

 

Only in my opinion.

 

thanks for that IDO.

I suppose it depends on how you view those statistics. For sure ECMWF is falling very sharply so also is GFS, a bit less than ECMWF though. To me that suggests that ECMWF and GFS at those time scales show similar frailty. Thus neigher can be really trusted perhaps. But if we use the 6-10 NOAA anomaly charts and, usually, the ECMWF-GFS versions, then we do get a better more consistent usually and usually also a more accurate handle on what is likely to happen. Certainly another item to try and have in mind when using any model output though-thanks again.

[johnholmes]

Since there's very little in the way of any decent cold weather on the horizon for the next few weeks (it would seem), my attention is now being drawn to some of the extreme wind speeds that the GFS has been churning out run after run post 192 over the past 4 or 5 days. 

 

I think what the synoptic models, especially the GFS are doing. is along the lines one would expect when checking the anomaly charts. With such a strong westerly Atlantic flow predicted at 500mb then the jet some 10-15,000ft above this height will be very strong much of the time. Minor ripples in it may well create the conditions for a fairly major low with subsequent very strong winds as it deepens as it moves on a track, probably (note probably) somewhere N of the NW of Scotland. In my view while the strong upper flow continues there is going to be at least one of these fairly deep, possibly very deep, surface lows.

Edited December 29, 2014 by johnholmes

[winterof79]

Looks straight forward to me this 

http://www.wetterzentrale.de/pics/MT8_Manchester_ens.png

 

Nothing guaranteed after Friday.

Edited December 29, 2014 by winterof79

[MR EXTREMES]

IDO the ECM's strat warming today is even stronger than last night so that's some good news.

If it happens and it may well be to little to late!.

Couple that with the vortex having a rest recently from wave activity allowing it to regenerate to some degree as we can see from all the models.

Let's add another talking point that a lot of more experienced strat posters feel that this may not benefit us in the uk.

The ecm throws a surge of higher uppers into the uk and deep into eastern northeastern Europe.

Cool wet windy with snow on the Welsh mountains and maybe at lower levels further north especially Scotland but even here boarder line as uppers are not as cold as recent event.

Gfs shows possible topplers as weather systems pass threw which would benefit northern and eastern areas if cold snap is wanted.

Tick tock though the winter pendulum swings further away from anything seen in better winters like 2010.

The strat influence is not a certainty neither is the influence of the Arctic heights mjo still in unfavourable area add strong northern arm of the jet plus a resilient polar vortex as like last year the vortex is underestimated.

Those hoping for a Greenland block might be worth waiting for February as this is a month when blocking can make inroads to Greenland as the zonal train relaxes its grip although this to is not a given.

The uk is about to really head towards a true zonal west to east pattern and it's likely to hold on for a fair amount of time.

[marksiwnc]

I have been reading about the snow that's due in Las Vegas over the new year period and what has caught my eye is nearly every time this has happened the weather here has warmed historically and it has produced cold and sunny weather in about two weeks after the date. Weird I know but things like this dont happen in Vegas too often. Infact there has only been 15 since 1930.. It's a good trend if you ask me. So sunny and cold in two weeks time. Perfect

[winterof79]

So we have two warmings to look forward to.

The here and now

http://modeles.meteociel.fr/modeles/gfs/runs/2014122906/gfsnh-10-6.png?6

And in 10 or so days time(pic courtesy of Matt hugo)

Interesting times ahead