Model Output Discussion - 05/01/2016 18z onwards

[Cheshire Freeze]

2 minutes ago, Mucka said:

So those talking up cold, where is it coming from, North or East.

Posting anomalies and saying cold yadda yadda on that basis is not very useful.

Please explain the pattern and evolution that brings prolonged cold so that we can monitor the progression.

Are you saying cold snap from the North, toppler, Scandi ridge, cold from the East with high pressure to our NE, or are you saying Atlantic ridge (renewed or not) and Northerly and Northeasterly with high pressure to the NW? Or are you just whistling in the wind?

Nice to get some meat on the bones if proclamations on detail are being made eh?

I'm still waiting for someone to show me a piece of conclusive evidence to suggest a cold spell of note is on the way next week?! Bar a couple of days where uppers are genuinely conducive to snowfall, the 18z looks like days of icy rain and sleet to me. Cold, yes, compared to what we've had during December- but that's not exactly hard!

The op runs are just not following the ensembles!

[bluearmy]

Scandi trough mucka. Atlantic ridge which ebbs and flows with the east American trough.  We are in between. Sometimes with the ridge more prevalent and sometimes the trough.  That's the envelope.  Now watch the models work out how it will resolve itself.

[Polar Maritime]

Why of 'note', CC? Only a 'cold' spell is shown/discussed/model'd to be on the way in the reliable for now at least.

[Cheshire Freeze]

6 minutes ago, Polar Maritime said:

Why of 'note', CC? Only a 'cold' spell is shown/discussed/model'd to be on the way in the reliable for now at least.

That's not what I've been picking up PM- infact some people are getting way ahead of themselves here. I don't know what extra info people like Fergie and Matt have but I can't see ANYTHING NWP-wise that suggests anything other than a messy, transient toppler type scenario next week. I'm really struggling on this one- maybe it's me missing something??

It takes a foolhardy so and so to blindly follow ensemble forecasting when umpteen ops from different organisations churn out the same eventuality...

Edited January 5, 2016 by CreweCold

[Polar Maritime]

Loads of posts hidden, Model Discussion only please.

[nick sussex]

Overall a somewhat underwhelming evening in terms of operational runs bar the UKMO.

The issue is the lack of oomph to move low pressure near the UK east or preferably se, a filling low over the UK with a modified flow is a bit like running downstairs on Xmas morning and instead of the latest X Box ending up with a Binatone tennis game(younger members won't have a clue what I'm on about)!

The lack of decent WAA into Greenland is a problem, the ensembles whilst offering more promising solutions have not been picked up by the operational runs which is troubling, this divergence is unlikely to last much longer.

Lets hope that they do tomorrow because tonights trend is all a bit stale buffet, mingy old coleslaw and cheap sausage rolls apart from the UKMO which offers some hope but has a poor record at being a T144hrs trend setter.

Although likely to turn colder I think having put up with 5 weeks of mild crud, cold and snow lovers in here deserve more than chasing around three hours of slush and BBC exclamations of bitter cold when the maps showing 6c and a gusty wind!

[tight isobar]

For note"

There is atm progression and dis-progression on both sides of the coin.

The unlikely scenario is progression with viable block-set to a northern westerly typo block' 

With dictate of what is atm the pesky large lobe Canadian vortex. ..

Which ironically could now be-or Aid in the evolution to a' north easterly typo' block going forward (courtesy Azores Hp).

All this before an incursion of Arctic air...snap...which will ultimately define..all above...

[Mucka]

11 minutes ago, bluearmy said:

Scandi trough mucka. Atlantic ridge which ebbs and flows with the east American trough.  We are in between. Sometimes with the ridge more prevalent and sometimes the trough.  That's the envelope.  Now watch the models work out how it will resolve itself.

 

For sure that is the triggering pattern but what we have so far is a pattern that can sustain 3 days cold, 4 absolute tops if the the trough plays ball, thereafter we need renewed blocking form somewhere.

So for me there is about a 30% chance or less that renewed blocking will come in the Atlantic, if it does great, game on but if it doesn't?

Well then we are looking to our NE instead which is also viable but my point is that it is not enough to say the mean is cold at day 10 without looking into how we get there and the progression involved. So the question is are people saying we will get Scandi high or are they saying we will get renewed Atlantic blocking because if the first attempted ridge toward Geenland fails (which looks likely) then any prolonged cold will require renewed blocking.

My personal opinion is that we are looking at around a 3 day cold shot and then a messy less cold transition with possibilities of renewed MLB or HLB thereafter but I don't see how any detail beyond that can be given assuredly, especially without the detail of progression from the now to then.

Edited January 5, 2016 by Mucka

[Polar Maritime]

1 minute ago, CreweCold said:

That's not what I've been picking up PM- infact some people are getting way ahead of themselves here. I don't know what extra info people like Fergie and Matt have but I can't see ANYTHING NWP-wise that suggests anything other than a messy, transient toppler type scenario next week. I'm really struggling on this one- maybe it's me missing something??

I think some maybe holding on the the well discussed background signals by G.P and maybe expecting to see something now regarding this in the model runs, But that's not expected until the last week of January so hopefully we may see signs of this next week. 

[Cheshire Freeze]

1 minute ago, Polar Maritime said:

I think some maybe holding on the the well discussed background signals by G.P and maybe expecting to see something now regarding this in the model runs, But that's not expected until the last week of January so hopefully we may see signs of this next week. 

I think that must be it. I fully agree things look better mid-late Jan!

[Chris K]

10 minutes ago, CreweCold said:

That's not what I've been picking up PM- infact some people are getting way ahead of themselves here. I don't know what extra info people like Fergie and Matt have but I can't see ANYTHING NWP-wise that suggests anything other than a messy, transient toppler type scenario next week. I'm really struggling on this one- maybe it's me missing something??

It takes a foolhardy so and so to blindly follow ensemble forecasting when umpteen ops from different organisations churn out the same eventuality...

Yes, but I think there has been a bit of crossover of discussion between what looks to be at transient cold snap short-mid term and perhaps more notable spell later in January with the N hemisphere undergoing a substantial change, therefore increasing our chances (but of course no guarantee...)

Unless you also mean longer term? Which then means your positive posts before Christmas of a change mid-late Jan now seems less likely now that it is starting to come into the closer timeframes?

Edited January 5, 2016 by Chris K

[feb1991blizzard]

2 minutes ago, CreweCold said:

I think that must be it. I fully agree things look better mid-late Jan!

It was always going to be a slow burner this, still confident but looking to me now more like 10th feb for complete breakdown of PV.

[Cheshire Freeze]

Just now, Chris K said:

Yes, but I think there has been a bit of crossover of discussion between what looks to be at transient cold snap short-mid term and perhaps more notable spell later in January with the N hemisphere undergoing a substantial change.

Unless you also mean longer term? Which then means your positive posts before Christmas of a change mid-late Jan now seems less likely?

Yes there has undoubtedly been crossed wires. There will be NO panacea of a cold spell next week. It'll be a 2 day window where we could see snow fall at any given location of the UK.

After that it's interesting BUT that's FI for now and we are not going to see a seamless slide into something of greater longevity after next week's brief flirt with winter.

[inghams85]

1 minute ago, Polar Maritime said:

I think some maybe holding on the the well discussed background signals by G.P and maybe expecting to see something now regarding this in the model runs, But that's not expected until the last week of January so hopefully we may see signs of this next week. 

Yay!!! Finally someone has talked sense. If posters care to read back 4 or 5 days GP forecast a cold spell between the 15 and 20th of November due to temporary amplification in the Atlantic and then a lengthy -NAO dominated cold spell from the 28th (of which he has brough forward to the 23/24th. None of the senior forecasters have forecast a severe spell next at any point. It's people seeing some of the more extreme runs and thinking this is the "torpedo" happening! It's not! It's merely a £20 rocket from Aldi until the real spell starts.  As had been discussed the true cold Synoptics are not in view until Saturday at the earliest. Get a grip people

[nick sussex]

Just now, CreweCold said:

Haha you sure have a way with words Nick! Stale buffet sums it up perfectly. It's food, it's edible but not necessarily appealing!

Thanks expect more melodramatics in the morning if the buffet gets even more stale! I'm underwhelmed not because I expected a proper Greenland high because I didn't expect to see any signs of that in the next ten days but frustrated at how its like pulling teeth to just clear that blxxdy trough east/se and develop a decent northerly flow.

Lets hope one of those nice GEFS ensembles or that nicer cluster in the ECM get picked up by the operational runs tomorrow and we can re stock the buffet with a bit of poached salmon and lobster.

[phil nw.]

Guys please stick to the model output.The team are working hard to keep this thread tidy and we have had to remove numerous posts since this new thread has opened.
Remember there is the banter and ramp thread for general chat.

Ta.

[Cheshire Freeze]

1 minute ago, inghams85 said:

Yay!!! Finally someone has talked sense. If posters care to read back 4 or 5 days GP forecast a cold spell between the 15 and 20th of November due to temporary amplification in the Atlantic and then a lengthy -NAO dominated cold spell from the 28th (of which he has brough forward to the 23/24th. None of the senior forecasters have forecast a severe spell next at any point. It's people seeing some of the more extreme runs and thinking this is the "torpedo" happening! It's not! It's merely a £20 rocket from Aldi until the real spell starts.  As had been discussed the true cold Synoptics are not in view until Saturday at the earliest. Get a grip people

It's what I've been trying to say all evening! I got the impression some people are analysing GFS runs at 5/6 days out and looking for a Greenland high. It's not going to happen...YET!

[inghams85]

1 minute ago, CreweCold said:

It's what I've been trying to say all evening! I got the impression some people are analysing GFS runs at 5/6 days out and looking for a Greenland high. It's not going to happen...YET!

No that's true and has never at any point been forecast! I think people just like to twist forecasts to give them hope for when they wake up to the morning models or the afternoons after work lol GP, IF, The met, Tamara are the biggest clues longer term and all have them have consistently said the last week of the month. All next week is is temporary amplification from the MJO signal. The week after the AAM will be hitting levels never seen before in January (record breaking even) and can only lead to Greenland height rises at this time in the year and a very very very interesting end to the winter 

[Mucka]

I know this must have been posted but JMA has wanted nothing to do with an Atlantic ridge before this evening.

Classic Winter chart.

 

[Glacier Point]

So I think I've spotted my torpedo off the starboard side in the North Pacific.

Next week we see a strong jet streak crossing the Pacific. This begins to decelerate and amplify as it interacts with the trough in the eastern Pacific, aided by a further amplification in the Asian jet tied into a trough in the western Pacific cerca 13th. 

The sub-tropical ridge is pumped into New Mexico and California around 20th. That instantly forces an eddy to break off in the polar flow as much of the flow is driven into the southern arm off Florida. Net result, mid Atlantic ridge is pumped north and north-east towards Iceland. -Nao triggered.

Period 17th January through to 7th February 1983 is your template.

last 3 gfs runs have toyed with this Pacific side evolution and dropping hints for the North Atlantic around 20th onwards.

Edited January 5, 2016 by Glacier Point

[phil nw.]

Tonight's T120hrs fax

all the polar air that's been lurking just to the north of Scotland for some days ready to filter south as the pattern starts to set up for the northerly next week.

[feb1991blizzard]

[Alexis]

I think you've got less reason to be despondent than most Crewecold. I'm more interested in seeing a Christmas Day 2004 style polar WNW setup in the current model runs at the moment.

[booferking]

UKMO & FAX charts for the same time not far apart

[karlos1983]

8 minutes ago, CreweCold said:

It's what I've been trying to say all evening! I got the impression some people are analysing GFS runs at 5/6 days out and looking for a Greenland high. It's not going to happen...YET!

CC, I think the coincidence of GP post yesterday along with JH on BBC broadcasting this Arctic high and change of pattern for NH is what is giving some the idea that this spell is the real cold Synoptics we've been craving. Clearly it isn't, but for what it's worth, I'm happy with what the models are showing next week, as it isn't to hard to see how we can get a route cold even after the high drifts east towards us, which looks like the trend to me. The good thing is it looks like it will be much colder by this time next week, and I certainly welcome that, with snow chances for some, even though it probably won't amount to much, but if we can get some decent cold in and some hard frosts this time around, that will only aid settling snow should we get the second/third bite down the line, as the ground is pretty warm at the moment.