Model Output Discussion - 18z 31/10/15 onwards

[knocker]

...albeit 12z EC clusters highlights some much more vigorous cyclonic outcomes possible from mid-month (out to T+360), & not solely tracking off up to the NW of UK.

 

Noted Fergie but I see the mean EPS anomaly at T360 doesn't actually look too bad with HP to the south  and weak trough the the NE and no significant troughing to the west.

Edited November 3, 2015 by knocker

[bluearmy]

Noted Fergie but I see the mean EPS anomaly at T360 doesn't actually look too bad with HP to the south  and weak trough the the NE and no significant troughing to the west.

But we know that ens means and anomalys at two weeks are not good indicators of specific features. The clusters are significantly better in that regard. enjoying watching the differences between the new GEFS and ECM extended to see if the GEFS are going to be a handy new tool as we head into winter

[Ali1977]

GFS consistent again with a cold Northerly, this time by day 12 not 15....Greeny high looks better.

Then this....crazy looking NH profile...

Edited November 3, 2015 by Ali1977

[bobbydog]

Fair enough, however so far the new GFS upgrade has resulted in this:

 

850 temp correlation day 6

 

ECM 0.773

GFS 0.729

 

day 8

 

ECM 0.570

GFS 0.478

 

day 10

 

ECM 0.362

GFS 0.272

 

These were the main biases as observed in the USA for the GFS,

 

Prediction of southward progression of cold air over done

Model a bit too extreme in temp patterns beyond 84 hours

Precip Type Algorithm off of GFS  too eager to depict snow 

Over forecast of cyclogenesis east of Rockies

 

That list won't come as a surprise, we'll of course reserve judgement to see how the GFS does after the winter.

thanks for the reply nick, just to be clear, you have far more knowledge of the models than i do, and if there is still a bias, you are in a much better position than me to spot it. my only issue was that people seem to forget about the GFS upgrade. time will tell and i look forward to your opinion on it.

[london and south east kent]

Hi all The cold is still there to night on gfs lets see if ecm sees this in next few days I can't see us being in a strong westerly later November we'll see.The meto might need change there further ahead forecasts to a more colder note..

[nick sussex]

thanks for the reply nick, just to be clear, you have far more knowledge of the models than i do, and if there is still a bias, you are in a much better position than me to spot it. my only issue was that people seem to forget about the GFS upgrade. time will tell and i look forward to your opinion on it.

I admit I completely forgot about that upgrade! The ECM doesn't avoid criticism especially over recent winters when its tended to come out with more outlandish scenarios than the GFS used to due to its bias to overamplify patterns. Of course these are much more focused upon in the winter months where we're looking at the outputs with a lot more interest. The one thing however regarding the GFS is its generous data that the public have access to so on that front it deserves credit.

 

I agree though only time will tell, hopefully the GFS upgrade will reduce some of that bias.

[Polar Maritime]

Way out in the run by the GFS showing a pretty cold picture tonight. With -6/-7 850's over the UK and even a flurry in the S/W, Nice to 'see'..

Edited November 4, 2015 by Polar Maritime

[pip22]

The GFS 00z is showing mild weather all the way through even in FI.

 

I find a possible breakthrough of cold on the 16th it is only a blink and you miss it affair though:

 

 

 

 

Overhaul it is going to be mild all the way according to the latest GFS 00Z. That explains no-one is posting anything this morning.

[Nick F]

The GFS 00z is showing mild weather all the way through even in FI.

 

I find a possible breakthrough of cold on the 16th it is only a blink and you miss it affair though:

 

 

Little change in the medium to longer range outlooks looking at the ens 500mb means/anomalies from ECM and GFS and yesterday's CPC 8-14 day H500 prognositc chart. Upper trough to the N and NW of UK, stubborn ridge over S Europe which occasionally builds north across mainland Europe when the trough amplifies out in the Atlantic.

 

 

 

So staying unsettled with mild SWlys much of the time, though the jet across northern UK dipping south occasionaly on the 00z GFS op to bring brief Pm incursions which will be more noticeable in the north. Conversely, potential for the ridge over Europe to nudge north to bring drier weather to southern parts.

 

Looking at the wider perspective, quite a progressive flow upstream over N America and the N Pacific with little signs of great amplitude or slowing of the flow, so nothing working through to change a great deal from what we've got now

Edited November 4, 2015 by Nick F

[legritter]

Morning all,seems to be all systems go for a generally mild first half of Nov looking at today's charts ,I am now in the IT age first post from a tablet here goes

[Cloud 10]

GEFS (p) ensemble mean still looking promising for some colder shots from the N/NW from mid-month onwards,although still a work in progress at the moment.

 

 

 

Meanwhile the GEM control run looks to have lost the plot.

 

[Captain Shortwave]

Not a lot cold wise going on again today from the models, if anything by the looks of it we could see the Euro high re-build again into week 2.

The ECM pretty bullish at day 10

Mean height of 1030mb in the far south, quite supportive of the operational. Luckily it is at 10 days out so we may see some changes.

 

The GFS not so keen and keeps a mixed westerly pattern.

 

Overall the picture seems to be that we will see an increasingly zonal picture with spells of rain mixed with brighter, showery intervals with the potential for southern areas to become drier again as we approach mid-month.

[carinthian]

A big change on the latest GFS (12Z) run. 10 days of Tm air mass for the bulk of the population then a dramatic change to polar air mass and then an Arctic front follows ? Long way off as always. Hope it turns out right though !

 C

[Ravelin]

A big change on the latest GFS (12Z) run. 10 days of Tm air mass for the bulk of the population then a dramatic change to polar air mass and then an Arctic front follows ? Long way off as always. Hope it turns out right though !

 C

 

Yeah, back to showing a Northerly. Toying with our emotions. Although in reality it's too early and too short-lived to do anything but whet the appetite.

 

 

Edit: Actually, this one tries to hang around...

 

Edited November 4, 2015 by Ravelin

[Summer Sun]

Anyone still up for a wintry spell around mid month?

 

 

Any precipitation would readily turn to snow as the colder air digs further south

 

:cold:

 

Edited November 4, 2015 by Summer Sun

[tight isobar]

Gfs becoming "systemic "

Again throwing up decent solutions ' of the road to cold highway ......

Ecm watched with a keen eye !

This evenings +240.

[BlueHedgehog074]

I remember when John Holmes mentioned it was advisable to compare the same model runs with each other; for example, comparing today's GFS 12Z run with previous GFS 12Z runs to see how the particular model updates are handling the weather patterns. Good for trend-spotting too.

For the sake of consistency, have compared yesterday's 12Z GFS run with tonight, albeit focusing on a certain day in the dreamland zone.

This was what the 12Z run showed yesterday for Tuesday 17th November...

...and this is what the 12Z update has shown for tonight on that day.

The run tonight sticks to a similar theme with a cold blast from the North over the UK with some kind if ridging in the Atlantic. As you would expect, the Nortgerlies on both aren't exactly the same. Scandinavian troughing on tonight's 12Z run, for example, is a bit deeper with a stormy looking Low over Scandinavia, plus the UK Northerly is a bit less potent.

Either way, interesting to see the GFS stick to a similar theme. And as great as it is to see, still wouldn't be worth considering looking outside watching those lamposts. As some posts mentioned in the last day or so, the GFS does seem to overdo the amplification of weather patterns in Fantasy Island. And even should an outcome like this come off, there's a good chance it could become watered down somewhat, especially if the models are underestimating the strength of the Jetstream in the Atlantic (which could result in a bit more of a flatter pattern with perhaps only the Northern UK being affected by a cool/cold shot from the North/North-West. Wouldn't, however, totally discount the GFS's Nortgerly ideas as it has shown similar scenarios in Fantasy Island in the last few days.

But... until the other operational models start picking up on the GFS's mid-Atlantic ridging and Northerly ideas (with also backing from the anomaly charts (such as NOAA) and the Met Office), would perhaps resist buying tickets to board any snow train service coming down from the North or East unless confidence grows for a colder spell. I'd imagine there's a lot of cold weather enthusiasts who'd love to board the snow train service (myself included), but as is the case with these things there's always a risk it could break down on it's way to the UK. From what I read yesteday, and something I agree with, getting deep cold into the UK at this time of year is hard and something that's more likely in December. And especially in January.

Just have to hope somehow the GFS is onto something (but for now, I expect there'll be some waiting at the station before the snow train service arrives unless possibly you live on/close to Northern hills).

[Ali1977]

This GFS is really good, and not in far reaches of FI - which makes me think it won't happen as the METO would surely have picked up on this by now. If ECM day 10 shows the same I'll be shocked but interested to hear what the more knowledgable have to say.

GEFS are not without interest neither.

[Man With Beard]

How quickly things can change! A few days ago we were talking of a locked-in Euro High producing a record mild first half of November - but the little low this week went over the High rather than under, and suddenly the Atlantic gets in. A little pressure rise between Atlantic lows and ... well, the GFS cold spell suddenly becomes just a little bit plausible. What a shock it would be though, air frosts nationwide and single digit maximums.

[Ali1977]

This GFS is really good, and not in far reaches of FI - which makes me think it won't happen as the METO would surely have picked up on this by now. If ECM day 10 shows the same I'll be shocked but interested to hear what the more knowledgable have to say.

GEFS are not without interest neither.

I think ECM holds some interest going forward from day 10, doesn't really back up the GFS which is as expected.

[knocker]

Quite a mild pleasant ten days with the ecm

I think ECM holds some interest going forward from day 10, doesn't really back up the GFS which is as expected.

 

Could you be a little more specific?

Edited November 4, 2015 by knocker

[blizzard81]

It is too early for the meto to throw it's weight behind a cold spell that is two weeks away. They are always cautious when it comes to forecasting cold spells. I expect them to come on board in the next couple of days. A cold spell in 2 weeks is just about nailed on imo. GFS consistent on this from 360 hours out, now into the 10 day range. Oh, the second reason - cold spells very often follow persistent foggy spells a couple of weeks later. If people haven't noticed this phenomenom over the years then they clearly haven't been paying enough attention

[Ali1977]

Quite a mild pleasant ten days with the ecm

 

Could you be a little more specific?

WAA is pumping up into Labrador and above at day 10, once that low pressure in the Atlantic sweeps though day 11/12 ish it would open the Door to a Northerly with heights up around Greenland.

I will add, I'm by know means knowledgable in this field - so this is my interpretation and prob Not anywhere close to being correct.

[fat chad]

Quote "A cold spell in 2 weeks is just about nailed on imo."

I don't think that anything can be nailed on 2 weeks in advance....

[nick sussex]

So tonights GFS reverts to a few recent operationals with that high moving out of Canada and the pattern eventually progressing far enough east to bring down that colder n/nw flow.

 

The ECM is less progressive but at least now agrees with that Canadian high, I think the issue is more whether low pressure will get sufficiently east or whether it will be slow moving to the nw.

 

At least theres a hint of some change towards mid-month but in terms of anything much colder the juries out for the timebeing.