Model output discussion - 1st December onwards

[Frosty.]

2 minutes ago, Snowmut said:

Winters coming !!!

 

  Yipeeeeeeeee !!!!!

If ...and it's a BIG IF the met office say so, I will believe it, until then it's only FI eye candy! Besides, there is more strong winds and heavy rain to worry about in the week ahead which is desperately sad for the flood hit areas but I certainly hope we are going to see a marked change to wintry weather early in the new year. 

[John Badrick]

56 minutes ago, knocker said:

What a scenario!! You have the upper trough running down the N. Sea to southern Spain with the jet zipping around it's western flank and the HP ridging north from SE Europe. Just ripe for a low to nip down the trough and stall to the SE bringing an easterly snowfest to England. Really doesn't bear thinking about.

You know things are looking up and going in our favor (coldies) when knocker mentions the s word

[Carlrg]

Frosty, that Scandi ridge does look pretty unmoveable though on the UKMO T144 charts.

Edited December 27, 2015 by Carlrg

[gottolovethisweather]

11 minutes ago, Snowmut said:

Winters coming !!!

 

  Yipeeeeeeeee !!!!!

According to those charts it's still at least nine days away, nice to peer over but... That is not to say, something better isn't on its way, these charts are increasingly showing up in mid-range timeframes which can only be good. At least Eastern Europe has something to savour too, last snow they had was in October I believe, so its not just in the Uk who are snow-starved. Average to colder than normal Temperatures would be a good start, which is precisely what those charts show. 

[Ali1977]

Things do look like changing, but having just read the latest METO I would suggest the charts are wrong....I wonder if we'll see the Scandy high being modelled much further East over the next few runs....either that or the wording of the METOs forecast may start changing!!

[Snowman.]

1 minute ago, Ali1977 said:

Things do look like changing, but having just read the latest METO I would suggest the charts are wrong....I wonder if we'll see the Scandy high being modelled much further East over the next few runs....either that or the wording of the METOs forecast may start changing!!

It's difficult to predict, if I was going to give a forecast I would also go with the no slider version.

[Polar Maritime]

Agreeing with the above..Let's please leave the METO extended text forecast for the relevant threads please, Thanks.

Edited December 27, 2015 by Polar Maritime

[Liam J]

EPS control looking very unsettled for the UK & NW Europe post T240 out to T360 (end of the run) which would bring a continued risk of flooding and gales at times. It wouldn't be as mild as recent weeks though with blasts of PM air.

Edited December 27, 2015 by *Sub*Zero*

[northwestsnow]

14 minutes ago, gottolovethisweather said:

According to those charts it's still at least nine days away, nice to peer over but... That is not to say, something better isn't on its way, these charts are increasingly showing up in mid-range timeframes which can only be good. At least Eastern Europe has something to savour too, last snow they had was in October I believe, so its not just in the Uk who are snow-starved. Average to colder than normal Temperatures would be a good start, which is precisely what those charts show. 

Dont bothe reading it frosty, its depressing.

im still believing though, the battle between east and west is just beginning, the undercut is gathering momentum on the 00z runs so lets give the metoffice dudes another day or two before they begin to change their tune...

[Catacol]

1 hour ago, IDO said:

Just a sense of trend, the signal is hinting at the COD after D7:

JMANUKME:NCPE:

JMAN:ECM mean

 

 

 

None of those hit COD in the reliable as you can see - and if you check the 2 week verification stats for MJO modelling you will see that consistently the output has been underestimating the strength of convection.

The fact that even Knocker - who loves to post ensemble means and long distance EC32 forecasts that inevitably smooth out features - is acknowledging significant amplification is news in itself... and the reality of the MJO forecast and hindcasts suggest that January is not going to be a story of never ending westerlies. I suspect, like many others, that we will need a bit more time to see the vortex reduced and the atlantic quietened down.... but I am drawn again to twitter comments from Chio a while back suggesting we were running a fortnight ahead of normal. I am getting that feeling strongly now, and it is most encouraging to think that instead of looking at the last half of January and hoping for a change in pattern we are doing it before we even reach NY. 

I'd like to hear GP's take on the current situation. Could we really get a genuine retrogression of the pattern earlier than most thought was possible? Gulp... could we even get northern blocking in place just at the time when the vortex gets battered into submission and the AO turns negative with MJO forcing driving cold air out of its nest? That is a tantalising prospect. 

Edited December 27, 2015 by Catacol

[Nouska]

1 hour ago, chrisbell-nottheweatherman said:

Hi Nick, as mentioned above, IDO on the previous page of this thread mentioned the MJO entering the COD post-D7.  Any sign of that (obviously not in the CFS ouput you posted, but elsewhere)?

Probably best to see the main models on the same chart as it does explain the original comment about returning close to neutral. The four ensemble members from the CFS are in sync with the more amplified signal from the GEFS - it may be correct but it is usually much more generic than what actually takes place.

[gottolovethisweather]

12 minutes ago, northwestsnow said:

Dont bothe reading it frosty, its depressing.

im still believing though, the battle between east and west is just beginning, the undercut is gathering momentum on the 00z runs so lets give the metoffice dudes another day or two before they begin to change their tune...

I'm not frosty although I'm hoping it'll turn frosty some day soon. 

[John Badrick]

36 minutes ago, Carlrg said:

Frosty, that Scandi ridge does look pretty unmoveable though on the UKMO T144 charts.

I know, what's wrong with frosty? He'd usually be all over this

[Snowman.]

1 minute ago, John Badrick said:

I know, what's wrong with frosty? He'd usually be all over this

The fact that the north of England is experiencing the worst floods in decades and that chart just adds more.

[Frosty.]

2 minutes ago, John Badrick said:

I know, what's wrong with frosty? He'd usually be all over this

I'm fine, just waiting and hoping the experts see growing support for a pattern change in the days ahead...fingers crossed.

[damianslaw]

Changing times perhaps... lots of change shown in the model outputs compared to what we have endured for the last 2 months.

Key factors - warm advection into scandi in recent days is continuing in the short term enabling heights to build strongly further east over western Russia - stalling frontal activity from the atlantic edging it NW at first and then crucially SE, with the jet forced more NW-SE alignment - (this latter change has been consistent in all models in recent days) - final outcome very good chance of trough disruption with heights locked in place to the NE.

Lets see how things develop over the coming 2 or 3 days. The start of 2016 could see a battleground of sorts develop.

 

Edited December 27, 2015 by damianslaw

[knocker]

Michael Ventrice ‏@MJVentrice 23h23 hours ago

An evolving MJO will superimpose onto a strong #ElNino base state this week; Big response in global circulation +AAM

[Froze were the Days]

7 minutes ago, Frosty. said:

I'm fine, just waiting and hoping the experts see growing support for a pattern change in the days ahead...fingers crossed.

Yep Frosty agree...any experienced/veteran of watching models knows that 9/10 days away on modelling continental (easterly) weather to this country in winter is frought with twists and turns. Overall the trend is there and far better model watching than anything we've seen over the pathetic last 2 months! fingers crossed too...

Edited December 27, 2015 by Froze were the Days

[Nick F]

1 hour ago, nick sussex said:

Because this moves more quickly this could explain why theres the differences between the smoothed out version versus the normal models.

The MJO isn't an exact science and theres still arguments amongst scientists( whats new!) However my view is that the NWP is currently catching up to the real MJO versus the Kelvin wave.

This is why I've been a bit more optimistic over the last few days because essentially there was room for upgrades.

We'll see over the next few days whether we can continue to see that Russian block strengthen and whether that trough disruption is more favourable.

 

There is still ongoing debate on a few of the US forums and twitter about whether the MJO signal is actually bonafide or bogus, a walker cell convective flare-up over the tropical Pacific has perhaps been interfering with the MJO signal. And also the forecast rather coherent/amplified MJO signal is unlikely during a very strong El Nino - which historically tends to subdue the signal. Furthermore, looking at the DJF MJO plots, there has only been 3, I think, MJO waves through 8/1 in January during an ENSO event of >1.0C since the late 70s. Those were 1998, 1992 and 1983. And those MJO 8/1 phases didn't play to the usual composites of those years.

Whether the MJO signal is bogus or not, remains open to debate and it remains to be seen whether it is actually the driver for the blocking signals over western Canada and Scandi/NW Russia ... or whether it's working in tandem with El Nino, or El Nino is more likely IMO the driving force for this pattern change,

Be interesting to see if the Scandi/NW Russia block and Greenland PV will retrograde enough to allow that developing deep cold pool west towards us. Confidence in NWP output in these situations can often decrease with regards to how much energy goes NE over the block and how much under the block. But the fact that the 500mb pattern is retrograding upstream with the Aleutain/Alaska low moving westward over the Bering Sea to be replaced by a ridge over Alaska/western Canada will surely suggest the trough over the N Atlantic and Greenland will too edge west as a trough carves out over eastern US/Canada - which is a big positive step for that Russian cold to back west towards the UK and force the jet south into SW Europe.

Even if it takes a few bites of the cherry to tap into the cold to the east, as I mention in the strat thread, the PV looks increasingly doomed as we head into late winter, as not only is the strat vortex being attacked by trop wave activity over Alaska and Scandi, the wQBO is showing signs of weakening towards neutral and maybe going slightly negative. A weak QBO is, apparently suggested by research, better for high latitude blocking than with strong westerly or strong easterly QBO phases.

Edited December 27, 2015 by Nick F

[knocker]

Just in time for a little daub before the rugby based on the 06z anomalies which maintain an unsettled W/SW regime and in the process remove the Russian HP

 

[Timmytour]

I'm seeing some rare developments..... Frosty being cautious and Knocker ramping cold

[Nick F]

06z GEFS teleconnections all trending in the right direction:

AO

NAO

Also liking the 00z GEFS mean cross polar meet-up between the Alaskan ridge and Scandi/Russian ridges, that's gonna squeeze the trop vortex and push that jet south ...

 

Another reason we want that undercut, other than many of us wanting it turn much colder of course, is if the jet energy all diverts N/NE against the block to the east, we end up with slow-moving fronts aligned to a moist S/SW flow that will continue to bring further persistent rain to those areas that have seen way, way too much already. Get that undercut on the rains go south.

A slow-moving frontal boundary indicated by the models for Weds/Thurs this coming week, could bring more flooding problems to the west on top of the fronts passing through the next few days (albeit moving more quickly earlier this week)

GFS and ECM both advertising a spell of snow over Ireland and Nern UK Thursday night, as cold Pm air undercuts from the west, looks like the excessively mild days are numbered ...

Suddenly the weather's got interesting ...

Edited December 27, 2015 by Nick F

[Mucka]

The picture is coming into focus now.

The initial long shot Easterly we were chasing via our Scandi high is seemingly off the cards with the high being forced too far NE (not enough trough disruption and energy going under the block) - that is being modeled across all output.

However we are now looking to a second bite of the cherry via a trigger low which I discussed both last night and this morning. The track of this low is absolutely key.

This will be the first opportunity (there could possibly be another chance depending on strength and orientation of the block but really it is this low that we need to help us out. ECM has brought this low further South moving it more toward today's GFS ,while GFS itself had this low diving South West of Europe yesterday but has now corrected that and is currently being programmed to come up against the block just SW of UK which is ideal to get some disruption and undercut.

This afternoon we can follow the track of this low across the Atlantic from Dec 31st.The other big piece of the jigsaw is obviously all about the positioning and orientation of our block when this low comes to meet it.

 

Good to see ECM ensembles go a little cooler this morning but whether we get cold sooner or later or not at all I truly hope we can get something drier given the dire situation in parts of Northern England. The signs are that blocking will become more likely as we move through January - fingers crossed.

 

Edited December 27, 2015 by Mucka

[Alpine glow]

Hi. Have been watching the model forum for many years now and tried to learn things on the way.

may I ask a couple of questions regarding the current progged set up without causing too much disruption? Just want to validate a couple of things in my mind really.

i'm wondering about the SW low andwhy it's so important. Am I right in thinking that if it cuts under and merges with the scandi High, it will produce snow? Is this because the milder air is merging with the cold air. Also, is it this kind of set up (if it happens) that produces a channel low?

if it doesn't undercut, is the Scandi high enough to produce snow with the right ingredients? I think this is the closest I've ever understood anything and it feels good to understand a little no matter how basic.

whilst I'm here, I'd just like to say the all posters no matter what the style have always been great for me which is what makes the forum the best on the Internet

 

edit : oops, write this when quiet and now lots of posts are happening. Ignore it if it's in the way.

Edited December 27, 2015 by Alpine glow

[Eskimo]

22 minutes ago, Alpine glow said:

Hi. Have been watching the model forum for many years now and tried to learn things on the way.

may I ask a couple of questions regarding the current progged set up without causing too much disruption? Just want to validate a couple of things in my mind really.

i'm wondering about the SW low andwhy it's so important. Am I right in thinking that if it cuts under and merges with the scandi High, it will produce snow? Is this because the milder air is merging with the cold air. Also, is it this kind of set up (if it happens) that produces a channel low?

if it doesn't undercut, is the Scandi high enough to produce snow with the right ingredients? I think this is the closest I've ever understood anything and it feels good to understand a little no matter how basic.

whilst I'm here, I'd just like to say the all posters no matter what the style have always been great for me which is what makes the forum the best on the Internet

 

edit : oops, write this when quiet and now lots of posts are happening. Ignore it if it's in the way.

You have the high pressure to the Northeast and a low to the south, they act like a set of gears. Low pressure spins anti-clockwise and high pressure spins clockwise, dragging the cold westwards towards the UK. Ideally we need the low to slip under because it acts as a catalyst, really pulling at the cold towards us. If we didn't have the low, then the cold will just keep spinning around the high pressure across E-Europe and Russia and not really give us anything, leaving us in this kind of 'no mans land' of cooler temperatures but nothing special. Of course, having the low push underneath us gives much of southern England and possibly Wales the chance of snowfall as well, as the colder air starts digging into the moisture associated with the low. 

Hopefully this helps, as this really would be the pinnacle of bringing in a sustained bitter easterly. 

Edited December 27, 2015 by PerfectStorm