Model Output Discussion - cold spell to end Autumn

[Mucka]

Although the output looks poor on the face of it I think it is possible we are seeing the models seeing a new evolution which will lead to Northerly, just a later one than originally modelled.

GFS/UKMO 144 comparison

Rather unintuitively the new flatter pattern out to mid term may help us so long as we can get some amplification upstream by allowing the shortwave lows to eject East and phase with the main trough retaining some Atlantic blocking not allowing the Atlantic in proper.

UKMO is better upstream than GFS and the 168 chart would likely show a Northerly which could become accentuated by those shortwaves ejecting East. There is a danger of a West based neg NAO developing if they phase to far North and/or West but if they phase further South and/or East they could actually be a big help.

If this is correct we will see a slow transition to a Northerly anything from one to a few days later than initially modelled recently dependent on how clean any development is.

All bets are off for me until we see if this signal is correct and and how it is modelled with any consistency but don't be surprised to now see the first programmed Northerly fail only to be replaced by another.

Fascinating developments this morning.

 

Edited November 30, 2017 by Mucka

[carboncowboy75]

Gfs 192 looks promising 

[IDO]

+ EPO and PV lobe over Canada/Greenland = fast jet + flatter pattern UK segment.

Best we can hope for is cold zonal in medium term. 

After mid Dec flattening EPO so reset. See what that brings?

[jvenge]

25 minutes ago, carboncowboy75 said:

Gfs 192 looks promising 

Promisingly wet? Or windy?

[cheshire snow]

LOL

By T276 We get the Northerly,Watch The ECM have a change of Heart

C.S

[Tracy Flick]

Some members still offer a northerly or north-easterly.

Some don't.

[Mucka]

1 hour ago, Mucka said:

Although the output looks poor on the face of it I think it is possible we are seeing the models seeing a new evolution which will lead to Northerly, just a later one than originally modelled.

GFS/UKMO 144 comparison

Rather unintuitively the new flatter pattern out to mid term may help us so long as we can get some amplification upstream by allowing the shortwave lows to eject East and phase with the main trough retaining some Atlantic blocking not allowing the Atlantic in proper.

UKMO is better upstream than GFS and the 168 chart would likely show a Northerly which could become accentuated by those shortwaves ejecting East. There is a danger of a West based neg NAO developing if they phase to far North and/or West but if they phase further South and/or East they could actually be a big help.

If this is correct we will see a slow transition to a Northerly anything from one to a few days later than initially modelled recently dependent on how clean any development is.

All bets are off for me until we see if this signal is correct and and how it is modelled with any consistency but don't be surprised to now see the first programmed Northerly fail only to be replaced by another.

Fascinating developments this morning.

 

Alluding to my previous post, new evolution to a delayed Northerly possible.

There are a few ensemble members who bring the new evolution I suggested they may move toward.

They are by no means definitive examples and I expect upstream to be more amplified so the ridge to be stronger and a little further West if it comes off. (It is of course one possible solution of many but seems a very feasible way to rescue victory from the jaws of defeat.)

I will use p10,19,20 to show how they all have the failed Northerly 144 

You can see that they all have the shortwave ejecting East allowed by the flatter pattern instead of rolling North up the now demised ridge.

After they phase with the trough they look like this at 180.

Because of the upstream pattern p10 and p20 quickly break the ridge down in FI but p19 produces this by day 10

I know this glass half full given the output but I think the initial Northerly is pretty much dead but this delayed one still has a genuine chance of coming into our sights very quickly in the Op output.

I at least expect to see something similar modelled today or tomorrow by one of the main models.

I would forget the ensemble graphs for now, they are of little use when the models are searching for a new signal.

I can't really see any other way the pattern can reamplify quickly so fingers crossed.

Edited November 30, 2017 by Mucka

[The PIT]

As expected the GFS has twitched towards the ECM solution. So the developing trend is towards a milder mobile outlook possibly. The next few runs should show that. However in deep fi big switches can still occur at any point.

[ScottishSnowStorm]

The 0z as i looked at it wasn't all that bad yeah it didn't produce the northerly that we are all expecting but that was never stuck on with realistically anything past 120hr being a shot in the dark right now but there are aspects in the 0z which stand out in the evolution that are worth noting.

Lets start with our first charts at  156hr and as we can see from this chart there are a few things of note

Firstly the low pressures in the atlantic which instead of merging and moving northward actually seperate and part of the energy moves north east and leaves a seperate low pressure south in the atlantic

Secondly we see better development of WAA over the eastern seaboard of canada which in turn starts to produce a stronger ridge in this area

Next at 180hr we see the one area of low pressure being left alot further south in the atlantic which is good and we also see the WAA really going up the western side of greenland another good thing to see

The one bad point in it all is how deep the low over the UK is but it is certainly starting to displace the hieghts over europe

Then as we see this develops into hieghts being pulled towards greenland with the low in the atlantic aiding the push of WAA into greenland in doing this now we could probably do with that part of the PV being a little further from greenland but with the NOAA prognosis earlier was calling for that part of PV moving northwestward away from greenland so i am sure we would gain a little westward movement 

Also to notice from this as well is hieghts building east of greenland which is always better for us here 

Now eventually the run doesnt work out and the ridge starts to fall as seen here 

So although not giving us our northerly it is quite a good solution up stream for us which shows better WAA into greenland than the weak shortwave filled affair we have been seeing

But of course it is just another solution and is always open to change especially the way the models are acting 

[booferking]

Yep as expected no Northely get ready for the return of the jet, states goes in to the freezer again never bodes well.

Edited November 30, 2017 by booferking

[knocker]

Today starts with the familiar patter of low pressure centred southern Sweden and the high cell west of Ireland so the UK still in the cold, breezy northerly with wintry sowers down the coasts but more particularly in the north and down the east coast. A widespread frost this morning and icy in many places.

During the day, with the high tending to ridge NE the low will track south to northern Germany thus veering the wind NE and with troughs appearing in the flow more concentrated showers down the east coast (some still affecting the SW) which will be borderline vis rain, sleet or snow.

Overnight these will clear the south east as the ridge moves south cutting off the northerly and by 12 Friday a front accompanied by cloud and rain will be affecting the north west with temps on the rise to around average,

Over the weekend the high pressure will stay centred to the SW of Ireland thus the UK in a north westerly flow and mainly dry apart from showers in the NW and temps around normal. This is the synopsis at Monday 00 with the overall pattern not unfamiliar with the twin energy flows, one around Greenland and the other out of the eastern seaboard that are both putting the high cell under pressure

But the high is nothing if not resilient and although it has been shunted east by 12 Tuesday the UK remains under it's influence. But during the shunt a wave has developed on the front associated with the main trough to the west and has traveled quickly around the high pressure via Iceland, where it phases with the colder trough to the north , and by the same time Tuesday is in the Norwegian Basin with the front lying west-east north of Scotland. This is the boundary between the cold and warm airmasses.

So where from here? Over the next 24 hours the front moves a little south  over Scotland as another wave forms on it as the main trough to the south west continues to push north east but the rest of the UK remains under the auspices of the resilient HP and in warmish westerly zephyrs.as the delineation between the cold and warm air remains along the front.

It would be wise to stop here as I don't give any credence to the evolution from this point but just to note it. The main trough continues to push NE and develops into an intense are of low pressure over the UK which if did occur, would bring blizzards to many places. Best forget it

 

Edited November 30, 2017 by knocker

[swfc]

I was musing over what tamara said recently over people looking at the nhp and expecting major blocking. The profile going threw next week shows atlantic ridging "trying" to get quite a Way north but being suppressed to a degree. No real sign of any lasting block which is basically what she meant.

[NO LONGER POSTING]

I was going to write yesterday, how many times have we seen the GFS crawl towards the ECM output compared to the ECM go towards the GFS... Anyway, it's not even winter yet and a lot people have experienced some pretty wintry stuff.

[ScottishSnowStorm]

22 minutes ago, ScottishSnowStorm said:

The 0z as i looked at it wasn't all that bad yeah it didn't produce the northerly that we are all expecting but that was never stuck on with realistically anything past 120hr being a shot in the dark right now but there are aspects in the 0z which stand out in the evolution that are worth noting.

Lets start with our first charts at  156hr and as we can see from this chart there are a few things of note

Firstly the low pressures in the atlantic which instead of merging and moving northward actually seperate and part of the energy moves north east and leaves a seperate low pressure south in the atlantic

Secondly we see better development of WAA over the eastern seaboard of canada which in turn starts to produce a stronger ridge in this area

Next at 180hr we see the one area of low pressure being left alot further south in the atlantic which is good and we also see the WAA really going up the western side of greenland another good thing to see

The one bad point in it all is how deep the low over the UK is but it is certainly starting to displace the hieghts over europe

Then as we see this develops into hieghts being pulled towards greenland with the low in the atlantic aiding the push of WAA into greenland in doing this now we could probably do with that part of the PV being a little further from greenland but with the NOAA prognosis earlier was calling for that part of PV moving northwestward away from greenland so i am sure we would gain a little westward movement 

Also to notice from this as well is hieghts building east of greenland which is always better for us here 

Now eventually the run doesnt work out and the ridge starts to fall as seen here 

So although not giving us our northerly it is quite a good solution up stream for us which shows better WAA into greenland than the weak shortwave filled affair we have been seeing

But of course it is just another solution and is always open to change especially the way the models are acting 

This is also a very similar pattern we saw develop on yesterdays ECM 0z 

And also with this mornings UKMO 0z you can see where this pattern could come from this chart 

 

Edited November 30, 2017 by ScottishSnowStorm

[ScottishSnowStorm]

17 minutes ago, ScottishSnowStorm said:

This is also a very similar pattern we saw develop on yesterdays ECM 0z 

And also with this mornings UKMO 0z you can see where this pattern could come from this chart 

 

ICON same theme 

GEM similar as well 

[ScottishSnowStorm]

ECM moving in right direction as well 

Further west over canada and lows in atalantic seperate 

Edited November 30, 2017 by ScottishSnowStorm

[Dennis]

its a strong fight next week

[feb1991blizzard]

ECM was already saying no by 120.

[swfc]

Didn't think ecm could get any worse after yesterday's 12z.ah well roll on winter! !! Lol 168 looks ok 

Edited November 30, 2017 by swfc

[ScottishSnowStorm]

ECM 168hr and lows in the atlantic have seperated and not merged and pushed north and looking ok over eastern canada 

[comet]

2 hours ago, Mucka said:

Although the output looks poor on the face of it I think it is possible we are seeing the models seeing a new evolution which will lead to Northerly, just a later one than originally modelled.

GFS/UKMO 144 comparison

Rather unintuitively the new flatter pattern out to mid term may help us so long as we can get some amplification upstream by allowing the shortwave lows to eject East and phase with the main trough retaining some Atlantic blocking not allowing the Atlantic in proper.

UKMO is better upstream than GFS and the 168 chart would likely show a Northerly which could become accentuated by those shortwaves ejecting East. There is a danger of a West based neg NAO developing if they phase to far North and/or West but if they phase further South and/or East they could actually be a big help.

If this is correct we will see a slow transition to a Northerly anything from one to a few days later than initially modelled recently dependent on how clean any development is.

All bets are off for me until we see if this signal is correct and and how it is modelled with any consistency but don't be surprised to now see the first programmed Northerly fail only to be replaced by another.

Fascinating developments this morning.

 

My exact thoughts when viewing the models this morning.

Keep the faith people's the freeze is just delayed not postponed.

[That ECM]

All 3 at t144. Ecm and gfs go from here and still want to send heights to our nw. This model watching isn't for the faint hearted at the mo. 

[ScottishSnowStorm]

3 minutes ago, That ECM said:

All 3 at t144. Ecm and gfs go from here and still want to send heights to our nw. This model watching isn't for the faint hearted at the mo. 

GEM and ICON are having good goes with similar evolution as well

[cheshire snow]

9 minutes ago, ShortWaveHell said:

At 192 the ecm develops a sense of humor !! Goodness me 

And at T216 it' even better,just when GFS says no,The ECM comes on board 

C.S

Obviously FI Terotery 

[Ravelin]

The models taketh away and the models giveth... 

Not that the models have the much of a clue-eth. 

Oh, and there's enough of a covering of snow here this morning to start closing schools in the more weather prone, rural, areas.