Jump to content

Model Output Discussion 29th December - Into mid-Winter.


Recommended Posts

1 minute ago, AWD said:

I'm intrigued with the EC T240 chart.

I can't fathom where it's trying to go though.  Anybody care to hazard a guess at the following days likely upper air pattern?

, if you look to the south of Greenland, its flowing all the way towards Canada, this suggests to me that its got a West based -NAO written all over it, you want our high and the high over North Canada to link up, so the flow is a straight Northerly and a proper Greenland high.

Link to post
Share on other sites
  • Replies 7.9k
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

Evening All For those of us who have been here for a long while there is times when you know you have to throw in the towel on chasing cold & times ( very rare ) when you 'just know' that the

Boom goodnight vienna

People being a bit harsh on Steve Murr, at least he has the balls to try and read and predict what may happen from his viewpoint rather than just posting what charts show.

Posted Images

Slightly disappointing outputs tonight with the issue later that the models are picking up a signal to retrogress the high which ironically will send the PV east/se , the high never manages to gain sufficient latitude before that happens. If this is the case its whether we see a western negative NAO or whether this can be further east.

The UKMO really even less interested with the high the furthest south. I can understand the frustration of some members with the models reluctant to bring the deeper cold across the Channel. The GFS does have that interesting kink in the flow and both it and the ECM could still improve. One things for sure we want the UKMO to bite the dust !

  • Like 4
Link to post
Share on other sites
Just now, nick sussex said:

Slightly disappointing outputs tonight with the issue later that the models are picking up a signal to retrogress the high which ironically will send the PV east/se , the high never manages to gain sufficient latitude before that happens. If this is the case its whether we see a western negative NAO or whether this can be further east.

The UKMO really even less interested with the high the furthest south. I can understand the frustration of some members with the models reluctant to bring the deeper cold across the Channel. The GFS does have that interesting kink in the flow and both it and the ECM could still improve. One things for sure we want the UKMO to bite the dust !

I'm not convinced that chart is as bad as it looks at face value. It would be interesting if we could have rolled that forward another couple of days.

Link to post
Share on other sites
5 minutes ago, Jason M said:

I'm not convinced that chart is as bad as it looks at face value. It would be interesting if we could have rolled that forward another couple of days.

You can see it here, just the Atlantic bit, the high does get a bit further ne with a slack easterly flow into southern areas at T168hrs but that has even less chance of getting that colder upper air into the UK.

ukm168.png

 

  • Like 1
Link to post
Share on other sites
3 minutes ago, nick sussex said:

You can see it here, just the Atlantic bit, the high does get a bit further ne with a slack easterly flow into southern areas at T168hrs but that has even less chance of getting that colder upper air into the UK.

ukm168.png

 

Wasn't really thinking about the easterly as IMHO I think that's dead in the water tbh (at least the deep cold convective type). More that the high could get pulled up to the NW with a northerly within a few days. Always difficult with METO charts as the info is so limited.

Edited by Jason M
  • Like 1
Link to post
Share on other sites

I would usually post chart snapshots to 'firm my point/points. .However its pretty pointless.

This is because once again im going to use the word 'exactions'and at this point there are many on offer.the point basically being that the placement/placements of evolving pin-point of hp settlement are far and way from being nailed! And obviously placement of even a few hundred miles (which is not a great deal run to run) will continue to migrate/sink/extend heights' in the next 24/48hrs minimum. 

Given that its on an' even scale will it won't it focus..

But yet again it continues to be a v-blocked situ..and by this time tomorrow' it could be that placement is again favorable. ..or perhaps not...However its by far at least a cold outlook and again its all about exactions'and watching atm.

Edited by tight isobar
  • Like 7
Link to post
Share on other sites

The latest MJO forecast has agreement on a speedy move into phase 1. And the amplitude if it verifies looks quite good, I wonder if the UKMO are a bit concerned yet that their dismissal of the MJO was a bit premature!

Theres disagreement though with the MacRitchie one which reduces interference, that goes into a lowish amplitude phase 7 in the next few days.

The composites for either are nice for cold, looking at the ECM,GFS they seem to be following the latter ones script.

Edited by nick sussex
  • Like 1
Link to post
Share on other sites

Regarding the easterly, I think the ECM had the right idea but nailing down the details will always be difficult so we may get some sort of flow from the East but its always seem be the case to me it will be an easterly with high pressure influencing rather than low pressure influencing,

It will be nice if we could pick up more of a flow off the continent as not only this will bring colder upper air temps, it will bring drier air which will hopefully get rid of any cloud cover which will get trapped into the high and the chances of sunny days and frosty nights increases again.

It is now clear though the ECM over amplified a bit in the short term hence the milder air toppling in is now a bit more widespread but the evolution of the overall pattern(which is to suggest the outlook will become blocked) it got pretty much right hence why people rate the ECM so highly.

What we don't want too see which has been hinted at by other models is for this blocking high to turn into a blocking Euro high and I would not rule out this being the case just yet.

Link to post
Share on other sites

I agree with the above comments, next week looks increasingly cold and blocked with high pressure expected to become centred over the uk..we could still get an Easterly with a chance of snow flurries, the door is still ajar, no reason to be downbeat..full of potential for later in Jan.

  • Like 3
Link to post
Share on other sites
Just now, Zakos said:

I think the potential in the medium range is being overlooked

ECM101-144.GIF?12-0ECM101-168.GIF?12-0

With anomalies like these from the ECM at 144+ and 168+.... surely there is potential for a small shift in the output to produce snowy scenarios ?

At the very least for eastern england and across the south and southeast?

Many people have stated to wait until 72+ to be confident over an easterly.

Surely, by that logic, a snowy easterly feed could crop up after the 72 hour timeframe?

I think a snowy easterly was never really on the cards Zakos, as thicknesses are not all that low and even the ECM never forecast pressure to get all that low either. What could change is the UK taps into the colder air but it does now look like the ridge is not going to be as amplified as first thought so it will be tough to get especially cold air in terms of uppers at least. Do hope at the very least we get a SE'ly flow to help melt the cloud away as this high looks like it will start off as a cloudy one with a weather front trapped within it.

Link to post
Share on other sites
24 minutes ago, Geordiesnow said:

I think a snowy easterly was never really on the cards Zakos, as thicknesses are not all that low and even the ECM never forecast pressure to get all that low either. What could change is the UK taps into the colder air but it does now look like the ridge is not going to be as amplified as first thought so it will be tough to get especially cold air in terms of uppers at least. Do hope at the very least we get a SE'ly flow to help melt the cloud away as this high looks like it will start off as a cloudy one with a weather front trapped within it.

h500slp.pngukprec.png

A true convective easterly within a week is unlikely I agree

But we could surely see moderate snowfalls across england based on the 12z GFS

Depends what you're looking for I guess, watching snow fall is more than enough for me personally

 

 

Edited by Zakos
  • Like 2
Link to post
Share on other sites

So what does everyone think. These are the composites for phase 7 and 1 of the MJO.

Phase 7                                                           Phase 1

JanuaryPhase7All500mb.gifJanuaryPhase1All500mb.gif

Compare that to the outputs of the ECM and GFS towards day ten.

If its something like phase 7 with high pressure over Greenland then we need to see this either central to eastern based not west because a west negative NAO is risky, Atlantic energy will attack the weak point of the blocking, if you're lucky you get trough disruption to the south but theres a risk if the main block is too far towards Canada.

 

Edited by nick sussex
  • Like 4
Link to post
Share on other sites

The extended ens are all singing a west based neg NAO and to compound matters, they are headed towards a renewal of the Alaskan ridge to drive a chunk of the Siberian displaced vortex back to e Canada by the end of week 2. We need the eps to begin to change the NH profile in the 9/12 day timescale (as per the day 10 solution carried forward) so that we drive a pattern change to non west based - NAO  or the return of high Euro height beckons in two weeks time!!

  • Like 1
Link to post
Share on other sites

It really stands out to me that we're looking at stagnating cold across the UK later next week at a time when unusual NE US warmth coupled with vortex displacement to Siberia looks to completely take the oomph out of the Atlantic jet.

What this means is any attempt by Atlantic LP to move in should see it disrupt and cause a snow event - but odds are it won't manage to move in at all and we'll be looking for the Siberian vortex lobe to edge west, which is a big ask but has big rewards as Dec 2010 showed us.

The MJO looks feisty enough and there's enough lean toward phase 8 (remembering H-W plots are likely going to continue struggling due to multiple convective centres) that a believe we're actually in with a shout. Bonkers, I know!

  • Like 9
Link to post
Share on other sites
3 minutes ago, bluearmy said:

The extended ens are all singing a west based neg NAO and to compound matters, they are headed towards a renewal of the Alaskan ridge to drive a chunk of the Siberian displaced vortex back to e Canada by the end of week 2. We need the eps to begin to change the NH profile in the 9/12 day timescale (as per the day 10 solution carried forward) so that we drive a pattern change to non west based - NAO  or the return of high Euro height beckons in two weeks time!!

A sobering update indeed. Are you referring to this morning's ext ens?

Link to post
Share on other sites
7 minutes ago, nick sussex said:

So what does everyone think. These are the composites for phase 7 and 1 of the MJO.

Phase 7                                                           Phase 1

JanuaryPhase7All500mb.gifJanuaryPhase1All500mb.gif

Compare that to the outputs of the ECM and GFS towards day ten.

If its something like phase 7 with high pressure over Greenland then we need to see this either central to eastern based not west because a west negative NAO is risky, Atlantic energy will attack the weak point of the blocking, if you're lucky you get trough disruption to the south but theres a risk if the main block is too far towards Canada.

 

If you were to ask me what I think would be the sequence of events based on the ECM, that the MJO would be going into 7 then 1.

EDIT : sorry 1 then 7.

Edited by feb1991blizzard
Link to post
Share on other sites
5 minutes ago, Singularity said:

It really stands out to me that we're looking at stagnating cold across the UK later next week at a time when unusual NE US warmth coupled with vortex displacement to Siberia looks to completely take the oomph out of the Atlantic jet.

What this means is any attempt by Atlantic LP to move in should see it disrupt and cause a snow event - but odds are it won't manage to move in at all and we'll be looking for the Siberian vortex lobe to edge west, which is a big ask but has big rewards as Dec 2010 showed us.

The MJO looks feisty enough and there's enough lean toward phase 8 (remembering H-W plots are likely going to continue struggling due to multiple convective centres) that a believe we're actually in with a shout. Bonkers, I know!

Feb 1991 the eastern seaboard had warm temps in the low 20's when we had the snow. Good sign !

  • Like 1
Link to post
Share on other sites
13 minutes ago, feb1991blizzard said:

If you were to ask me what I think would be the sequence of events based on the ECM, that the MJO would be going into 7 then 1.

EDIT : sorry 1 then 7.

You have to take into some timelag. The phase 1 might look like what we're currently having but that's unlikely to be MJO induced given the phase is low amplitude and in the COD and has just left phase 5 and 6 going by the normal modelling. The MacRitchie one has a low amplitude phase 7 within a few days. The others shoot the signal right across the COD into phase 1 in which case if the MJO was the driver we might have seen a quick retrogression then back to easterly. Whatever happens I just don't want a west negative NAO and we can just hope that this isn't where we're going.

I think someone mentioned a few days ago a very good way of looking at the retrogression. Its a race between low pressure to the ne and low pressure in the Atlantic. You have to have the pattern sufficiently south and east before you get any phasing of those two. For example on the ECM T240hrs, I've circled those low heights, they musn't meet, you need the high retrogressing nw 'wards to cut that possibility off. That way you have a chance to pull the cold northerly down. If you get them phasing then its a hard slog from there unless upstream theres a signal to push the pattern east and currently the trend is for a more west negative NAO.

ECH1-240.gif

 

Edited by nick sussex
  • Like 6
Link to post
Share on other sites

ECM ens

EDM1-144.GIF?12-0   EDM1-192.GIF?12-0   EDM1-240.GIF?12-0

EDM101-144.GIF?12-0   EDM101-192.GIF?12-0   EDM101-240.GIF?12-0

It could still be cold under clear skies though the front on Sunday may end up stuck over us which could inhibit the sunshine amounts. In the end the trend is a southward correction though the south could still see a continental drift. Going towards week 2 the retrograde is still there but we seem to still keep heights close the the UK.

Looking at the way things are panning out, I am starting to consider calling this winter "default to UK high". Maybe things will trend better and the northerly option in the extended range is plausible and there is still hope that we could drag the high further north over coming runs due to the complexities of the trough in the Atlantic and the Euro low even in the 3-5 day range.

Edited by Captain Shortwave
  • Like 7
Link to post
Share on other sites
21 minutes ago, nick sussex said:

You have to take into some timelag. The phase 1 might look like what we're currently having but that's unlikely to be MJO induced given the phase is low amplitude and in the COD and has just left phase 5 and 6 going by the normal modelling. The MacRitchie one has a low amplitude phase 7 within a few days. The others shoot the signal right across the COD into phase 1 in which case if the MJO was the driver we might have seen a quick retrogression then back to easterly. Whatever happens I just don't want a negative NAO and we can just hope that this isn't where we're going.

Right, cherrs I'm not really that knowledgeable on the MJO, what I would say regarding the west based -NAO though, I would much rather see one modelled at this range than a pattern too far East, I predicted a west based -NAO at the beginning of Dec when a really strong GEFS mean modelled one at serious range, but we always seen to end up with the pattern too far East so I'm never forecasting one again, a lot of people on here always say the models have the pattern too far East, I think the other way, I would rather start of with a West based -NAO, how many times in the last few years have we had the pattern 'TOO' amplified - not often, and how many times has the cold been out of reach and the continent to the East gets it? nearly every time I would suggest.

 

EDIT - yes Nick, agree, if those 2 troughs engage its game over, any time when troughs engage too far North its usually the end.

Edited by feb1991blizzard
  • Like 4
Link to post
Share on other sites
Guest
This topic is now closed to further replies.
×
×
  • Create New...