Model output discussion - heading into 2018

[nick sussex]

Morning all

Nice overnight developments with things trending the right way.

The GFS of course stands out as the best this morning upto T240hrs, we're not able to though clear completely shortwave energy to the nw. The ECM and GFS though absorb this into the upstream low without too many dramas. The main thing is no phasing takes place between the main low clearing se and the deep low leaving the ne USA.

Its hard to put too much detail this far out, chances of a slider low battle ground set up remain and a ne flow before that.

 

 

Edited December 29, 2017 by nick sussex

[chris55]

Both ECM and GFS trending colder this morning beyond days 8/9

A more diffuse pattern allowing heights to our north east to build

GFS day 10 would be mighty chilly with some really crisp frosty weather. And any sliders from the negatively tilted Atlantic flow could deliver snow.

Certainly something to keep our interest as we follow the models over the coming days

Edited December 29, 2017 by chris55

[bluearmy]

As I posted yesterday morning, it's pointless trying to resolve what happens with the ballon of heights thrown up - ops and ens will do various things with it for a few runs yet before honing in on a broad solution. And even that will be subject to change as we know the modelling tries to push any blocking (even transient) away too quickly. 

Remaining unsettled seasonal for the foreseeable with a few milder interludes chucked in further south. 

still no sign of the increased strat zonal flow affecting the trop by day 16. (Hemispherically speaking - we are Ina very mobile area !)

[TEITS]

A fasinating period of model watching which seems to be making any long range predictions virtually impossible. I recall my gloomy posts prior to xmas mentioning the jet angled SW-NE and very mild SW,lys and this likely to extend into the first couple of weeks of Jan.

What apparently seems to be happening is the models continue to be backtracking from this scenario with the 5th Jan seeing increased amplification with a ridge of HP in the Atlantic and a trough developing in the Med with the jet running NW-SE. We then have the scenario of building heights to our NE/E. The Oslo SLP mean supports this.

Im still not convinced any Scandi HP can resist the energy from the Atlantic but at this stage im going to sit on the fence. Seems to me this winter isn't reading the Teleconnections/Strat forecasts script. I say this not to be mischevious, but lets be honest I don't think anyone here would of been expecting to be discussing an E,ly via a Scandi HP!

[offerman]

25 minutes ago, TEITS said:

A fasinating period of model watching which seems to be making any long range predictions virtually impossible. I recall my gloomy posts prior to xmas mentioning the jet angled SW-NE and very mild SW,lys and this likely to extend into the first couple of weeks of Jan.

What apparently seems to be happening is the models continue to be backtracking from this scenario with the 5th Jan seeing increased amplification with a ridge of HP in the Atlantic and a trough developing in the Med with the jet running NW-SE. We then have the scenario of building heights to our NE/E. The Oslo SLP mean supports this.

Im still not convinced any Scandi HP can resist the energy from the Atlantic but at this stage im going to sit on the fence. Seems to me this winter isn't reading the Teleconnections/Strat forecasts script. I say this not to be mischevious, but lets be honest I don't think anyone here would of been expecting to be discussing an E,ly via a Scandi HP!

I would say it sall too far ahead don’t get excited only majority of the timea

to be let down. Forget looking to far ahead just concentrate on the next 3-4 days of charts of which we all know even these can change too........

 

[tight isobar]

Going to await supporting-data from the running 6z suite before any deeper analysis.

But just to say the 00z suites are a big leap to some decent/very interesting weather.

And this polar maritime flow is quickly evolving into a true notable feature as we move into new year...

Sliders/pop up features a-plenty...

And all on a possible route to the high climb....for a set up from east/north east...

Who can grumble!???....

Edit: and very foolish of me not to mention-that mlb teasing us with northerly incurs: 

Ive decipher'ed 4 slants at them in the next 8-days on route to possible more nirvana like synoptics.....

Great stuff imo!!!

 

Edited December 29, 2017 by tight isobar

[blizzard81]

40 minutes ago, TEITS said:

A fasinating period of model watching which seems to be making any long range predictions virtually impossible. I recall my gloomy posts prior to xmas mentioning the jet angled SW-NE and very mild SW,lys and this likely to extend into the first couple of weeks of Jan.

What apparently seems to be happening is the models continue to be backtracking from this scenario with the 5th Jan seeing increased amplification with a ridge of HP in the Atlantic and a trough developing in the Med with the jet running NW-SE. We then have the scenario of building heights to our NE/E. The Oslo SLP mean supports this.

Im still not convinced any Scandi HP can resist the energy from the Atlantic but at this stage im going to sit on the fence. Seems to me this winter isn't reading the Teleconnections/Strat forecasts script. I say this not to be mischevious, but lets be honest I don't think anyone here would of been expecting to be discussing an E,ly via a Scandi HP!

To be fair to the teleconnections experts, they were in fact gunning for a scandi high to be taking shape in early Jan back in early to mid December. This signal then waned somewhat but as we all know, the weather is a constantly evolving animal. 

[Snowjokes92]

A greenland high develops later on gfs bloody hell

[Nick F]

06z GFS delaying amplification over the Atlantic (vs 00z) until the low res part of the run it seems, but boy does look like putting on a show for coldies in FI!

Edited December 29, 2017 by Nick F

[nick sussex]

After a good start to the day the GFS 06hrs run delivers an underwhelming output  in the earlier timeframe and then tries to salvage things past day ten.

The Pacific profile shows big changes from the 00hrs run. Although this might be better in the longer term expecting things to go right well into FI after they've hit the buffers earlier doesn't have a good track record.

I'd rather the quickest route to cold , more time it takes to get there more variables can pop up nearer the time.

Nice try GFS but no thanks!

 

[Snowman.]

6z dismantles the PV in FI

 

[TEITS]

Classic example of what I mean.

Based on some of the comments over recent days with regards to the  Strat the GFS should not be showing these charts!

Also look at the difference between the 06 & 0Z. If a supercomputer can churn out such a massive difference then what hope do us humans have in making an accurate LRF!

[nick sussex]

Remember that wise Chinese proverb!

Better the pot of silver closer to home than the pot of gold at the end of the rainbow!

I made that up but you get my drift!

Lets hope this is a rogue run from the GFS.

[Summer Sun]

Looks like a very windy spell to end the year with Storm Dylan due Saturday night and into Sunday

[blizzard81]

The gfs 06z often goes against the grain so I wouldn't trust it at all, especially the low resolution part. The 12z runs will be the ones to watch. 

[Nick F]

Don't want to steal Man With Beard's thunder, but a look at the 00z EPS clusters shows fairly good confidence actually in the mid-Atlantic amplification, that then leads onto pressure/height rise over northern Scandi:

However, it maybe a short-lived affair the effect of the height rises to the N and NE, before the next surge of the trop PV moves in from the NW/W.

Given the strength of the trop PV influence upstream and the strat-trop coupling profile, it would be difficult to get a block to develop to the NE and keep the Atlantic at bay from the UK, unless more energy from the trop PV goes SE under the UK.

Edited December 29, 2017 by Nick F

[carinthian]

5 minutes ago, nick sussex said:

After a good start to the day the GFS 06hrs run delivers an underwhelming output  in the earlier timeframe and then tries to salvage things past day ten.

The Pacific profile shows big changes from the 00hrs run. Although this might be better in the longer term expecting things to go right well into FI after they've hit the buffers earlier doesn't have a good track record.

I'd rather the quickest route to cold , more time it takes to get there more variables can pop up nearer the time.

Nice try GFS but no thanks!

 

I think you have to make what you can out of this run, but its now clear to me a evolution of some kind is heading for a colder outcome towards mid January and potentially a snowy one for many. The mean control from GFS keeps even London location under zero Oc at 850mb level for the first 2 weeks of January which must be a good sign. Tonights run will probabaly be a different evolution but cold it will be ! Keep the faith Nick.

 C

[Paul_1978]

11 minutes ago, nick sussex said:

After a good start to the day the GFS 06hrs run delivers an underwhelming output  in the earlier timeframe and then tries to salvage things past day ten.

The Pacific profile shows big changes from the 00hrs run. Although this might be better in the longer term expecting things to go right well into FI after they've hit the buffers earlier doesn't have a good track record.

I'd rather the quickest route to cold , more time it takes to get there more variables can pop up nearer the time.

Nice try GFS but no thanks!

 

Surprised at the downbeat post Nick. Yes it's not as mouthwatering as the previous run, but taking the general theme overall without the inter-run dissection, then overall things are looking pretty good IMO. 

This chart is at T+180 for example. I'm not suggesting it's snow laden, but this time last year we'd have been jumping up and down with excitement seeing a chart like this at that time range. 

Edited December 29, 2017 by Paul_1978

[Man With Beard]

 

3 minutes ago, Nick F said:

Don't want to steal Man With Beard's thunder, but a look at the 00z EC clusters shows fairly good confidence actually in the mid-Atlantic amplification, that then leads onto pressure/height rise over Scandi:

However, it maybe a short-lived affair the effect of the height rises to the NE, before the next surge of the trop PV moves in from the NW/W.

Given the strength of the trop PV influence upstream and the strat-trop coupling profile, it would be difficult to get a bloc to develop to the NE and keep the Atlantic at bay from the  UK, unless more energy goes SE under the UK.

You are very welcome to steal my thunder as you imply, it's only a baby step towards a lasting Scandi High and may not last anyway, but I imagine GP and others may be very interested as this would match their predictions from weeks back.

Hypothetically, could result in a very snowy breakdown if there is to be one.

Edited December 29, 2017 by Man With Beard

[blizzard81]

2 minutes ago, Nick F said:

Don't want to steal Man With Beard's thunder, but a look at the 00z EC clusters shows fairly good confidence actually in the mid-Atlantic amplification, that then leads onto pressure/height rise over Scandi:

However, it maybe a short-lived affair the effect of the height rises to the NE, before the next surge of the trop PV moves in from the NW/W.

Given the strength of the trop PV influence upstream and the strat-trop coupling profile, it would be difficult to get a bloc to develop to the NE and keep the Atlantic at bay from the  UK, unless more energy goes SE under the UK.

I agree based on the current modelling and forecasts. Looks like this winter could be a case of plenty of cold spells but rather short lived affairs. Nothing disruptive over a long time period. 

[Methuselah]

11 minutes ago, TEITS said:

Classic example of what I mean.

Based on some of the comments over recent days with regards to the  Strat the GFS should not be showing these charts!

Also look at the difference between the 06 & 0Z. If a supercomputer can churn out such a massive difference then what hope do us humans have in making an accurate LRF!

I think we might be overlooking the invisible caveat (that goes along with any sort of attempted scientific prediction) ...all other things being equal? Although that tacit caveat often applies in controlled conditions, it seldom, if ever, applies to the real world...?

Anywho, like you, I have major doubts as to how accurate LRFs can be...It is an epistemological problem at heart...?

[Catacol]

27 minutes ago, blizzard81 said:

To be fair to the teleconnections experts, they were in fact gunning for a scandi high to be taking shape in early Jan back in early to mid December. This signal then waned somewhat but as we all know, the weather is a constantly evolving animal. 

Spot on. Frankly the idea that indications of height rises to the NE has come from nowhere is bizarre. It was flagged throughout December as the direction of travel due to GWO oscillation and phase of the MJO. Very briefly we got phase 8 before swift descent to the COD. 

Given the lag effects of the MJO signal and 4/8 GWO oscillation it is not surprising to see some NWP output toying with such a scenario in early January. However the big problem here is that the GWO went into sharp decline immediately before Xmas as the MJO wave dissolved away. Given this hard data the suspicion has to be that any height rise to the NE will be short lived and blown away by westerly energy. The reduction in tropical AAM has given a boost to momentum budgets in the extra tropics - combine this with the strengthening vortex profile and there is little support for any duration to a continental feed.

A brief flirtation with an easterly remains possible, but it would therefore go against all the signals if a scandy high set up shop for the longer term. Any window for battleground snow is likely therefore to be short - though the SW can benefit from these kinds of scenarios so I will have fingers crossed for any such window to stay open as long as possible.

[carinthian]

10 minutes ago, carinthian said:

I think you have to make what you can out of this run, but its now clear to me a evolution of some kind is heading for a colder outcome towards mid January and potentially a snowy one for many. The mean control from GFS keeps even London location under zero Oc at 850mb level for the first 2 weeks of January which must be a good sign. Tonights run will probabaly be a different evolution but cold it will be ! Keep the faith Nick.

 C

Certainly the models are firing out some interesting winter charts . This one from GFS showing the jet well south on the morning run at t240 with UK on the cold side of the Polar Front, so snow possible even down south  at times. All moving very quickly and looks like a cold evolution by day 10 of some sort !.

 C

[bluearmy]

The eps clusters back up my musings - anyone predicting what the second half of week 2 and into week 3 will deliver is tossing a coin. There are some that are contracted to do so - good luck! 

Edited December 29, 2017 by bluearmy

[TEITS]

23 minutes ago, Man With Beard said:

 

You are very welcome to steal my thunder as you imply, it's only a baby step towards a lasting Scandi High and may not last anyway, but I imagine GP and others may be very interested as this would match their predictions from weeks back.

Hypothetically, could result in a very snowy breakdown if there is to be one.

Sorry but I cannot let this one go.

If we read back to around Xmas we will see explainations from GP and others why an E,ly was now unlikely towards Xmas & New year. You will also note rather dire predictions for January of a mild, zonal spell. Should the current model output be proved correct then in my opinion it is wrong to say the predictions from GP & others weeks back are now correct.

The same was said to me many years ago when I was always predicting E,lys. The same rule applies!