Model output discussion - heading into 2018

[knocker]

5 minutes ago, Man With Beard said:

What don't you like about the clusters? (genuine question as a bit of critical evaluation will help us all in using them in the right way)

Perhaps I wasn't very clear. I don't have a problem with the actual clusters per se, but in evaluating them within the NH perspective. Of course naturally the site is geared for Iceland. It might just be me, unless I'm missing something, but in the ext range one has to go through every 12 hour period to attempt to glean anything useful vis trends that may significantly contradict, say, comparing the NOAA, GEFS and EPS anomalies when attempting to get a handle on the upper air pattern in the medium term. Having said that the clusters are of course another useful tool in the box. Just my opinion of course.

[knocker]

Today's mjo update from the ecm has it running through phase 2-3. The phase 2 composite anomaly is not a bad fit for the current EPS 10-15 anomaly.

Edited December 27, 2017 by knocker

[Singularity]

3 hours ago, Catacol said:

https://www.longpaddock.qld.gov.au/seasonalclimateoutlook/southernoscillationindex/30daysoivalues/

According to this data we have been seeing a Nino style setup in the pressure relationship since December 11 after a spell of much more predictable Nina values. Both October and November averaged +10, which given our Nina profile is not surprising.

So why have we had 2 weeks of Nino values in December? Somewhere there is clearly some "noise" affecting the expected pattern. Anyone got any ideas? 

Latest Schiraldi plots with the handy ability to jump back up to 5 days to compare runs show that, once again, we have models failing to spot the correct GWO progression. Is this linked to the strange SOI values? Is there more energy lurking in the pacific than the swift decline of the MJO a week or so ago suggested? By hook or by crook there is a drive back across to a low amplitude phase 3 and MJO forecasts in general are not holding it in the "circle of death" for long... which is a change from a few days ago

Overall conclusion? SOI index suggesting Nino-style forcing... added to Schiraldi plots pushing towards phase 3 rather than 1/2.... plus MJO re-emerging with some amplitude... added to the 23rd Dec graph from WDT on the 23rd showing frictional torques rising again (with MT expected to follow...) = a sense that the zonal spell may not last too much longer than the 2 week period I alluded to a few days ago. Back then 7th Jan was an easy time zone for minimum length of atlantic westerlies, and in my mind it could have run 1/2 weeks beyond this. However I think the timeline can be brought forward if this current data trend holds up. I think tentatively we can hope for a change of outlook by mid-Jan - at least in terms of some much better looking NWP output as we move towards Jan 15.

Just to be clear on what I mean by "better looking output" - my cards are firmly on the table. I am always looking for a high lat block - either over Greeny or Scandy. This is my definition of a setup for cold winter weather. Polar NW airstreams are quite possible in a zonal setup (eg last night and today) - worth being clear as to what benchmark we are actually using for forecasting success.

Overall therefore feeling a bit more optimistic this morning.

Great post as usual 

Glad to see I'm not the only one finding the projected re-development of MJO activity a puzzling feature given a supposed Nina background state, and the refusal of the GWO to dip as a sign that things aren't as some guidance tools would have us believe.

I sense that the Hendon-Wheeler diagrams under-represented the recent Pacific activity through 7-8, with the models now adjusting according to some residual downstream impacts resulting in some more interesting charts for later next week than some might have expected.

Still not sufficient to drive a significant period of HLB, but given the further potential down the line, it'll do for now. Hopefully some continued model adjustment will also serve to support the strong upper-stratospheric warming signals being offered in the 9+ day range by the likes of ECM and GFS.

 

If we can see enough upward-modification of the SSTs in the tropical Pacific to accompany the atmospheric Nino desires, we'll have a good shot at the next MJO progression not falling just short of the mark such as we saw with the last one. 

Even when ECMF and CANM show some moderate phase 3 activity as the MJO crosses the IO - that could be an interesting period. Some model output already hinting at the associated southerly-tracking lows. 

[Man With Beard]

20 minutes ago, knocker said:

Perhaps I wasn't very clear. I don't have a problem with the actual clusters per se, but in evaluating them within the NH perspective. Of course naturally the site is geared for Iceland. It might just be me, unless I'm missing something, but in the ext range one has to go through every 12 hour period to attempt to glean anything useful vis trends that may significantly contradict, say, comparing the NOAA, GEFS and EPS anomalies when attempting to get a handle on the upper air pattern in the medium term. Having said that the clusters are of course another useful tool in the box. Just my opinion of course.

Yes I think those are two clear limitations (lack of NH perspectives and time needed) - it is fortunate that the Icelandic perspective covers the north Atlantic and therefore our prevailing weather pattern, but they can't tell us about developments in the Arctic or over Russia, which funnily enough is of great interest if looking for an extended cold period. Thanks Knocker

[Catacol]

7 minutes ago, Singularity said:

If we can see enough upward-modification of the SSTs in the tropical Pacific to accompany the atmospheric Nino desires, we'll have a good shot at the next MJO progression not falling just short of the mark such as we saw with the last one. 

 

I hope so. MetO long range text is most definitely seeing a Euro high setup second half of January... suggesting MJO phase 4/5 and GWO not recovering its 4/8 orbit. It might just be that they are operating a few days behind the data that has adjusted in the last 48 hours - or more likely they have some high powered under the hood stuff telling them pacific forcing will fall short again and the vortex is going to take hold.

They got the end of this month wrong when look at it from early December - so they are not infallible... but I never like to see the MetO offside. They have become irritatingly able to nail patterns at reasonable distance. Takes all the fun out of independent forecasting.... |-[

[mulzy]

Got a very noobish question about the MJO - if we move into phase 3 for example, is there any lag before the analogue pattern for that MJO phase becomes applicable or is any response immediate? 

Edited December 27, 2017 by mulzy

[pyrotech]

7 minutes ago, mulzy said:

Got a very noobish question about the MJO - if we move into phase 3 for example, is there any lag before we the analogue pattern for that MJO phase becomes applicable or is any response immediate? 

There is a lag of around 2 weeks, i actually use 10 days for pattern change / effect over Europe, the official line i think is a bit quicker but following the phases i find 10 -14 days more accurate.  Phase 7 there fore , with me has effect 1st week of jan and should bring some wintriness. 

I follow 3 experts on here and their input is invaluable with MJO, but also use my own analysis

So answer is yes a lag, but time line may differ from mine

 

Plus no such thing as noonish question, we are all learning and better to ask than never know the answer

Edited December 27, 2017 by pyrotech
Added about asking questions

[knocker]

A good chance of a flake or two in the north and Scotland on Friday.

[Catacol]

24 minutes ago, pyrotech said:

There is a lag of around 2 weeks, i actually use 10 days for pattern change / effect over Europe, the official line i think is a bit quicker but following the phases i find 10 -14 days more accurate.  Phase 7 there fore , with me has effect 1st week of jan and should bring some wintriness. 

 

Dec phase 8 would have been much better... phase 7 was transition to high lat block, but amplitude fell away. Dont think much will come of this.

[knocker]

56 minutes ago, knocker said:

Today's mjo update from the ecm has it running through phase 2-3. The phase 2 composite anomaly is not a bad fit for the current EPS 10-15 anomaly.

I'm having one of those days, I meant to post the phase 2 composite vis the EPS anomaly

[knocker]

A good illustration this evening of a low forming off the eastern seaboard and ;bombing' it's way north east on a strong jet that also marks the boundary between the cold and warm air, Subsequent to this it continues to track north east leaving in it;s wake a strong NW Pm airstream about to plunge over the UK

Edited December 27, 2017 by knocker

[pyrotech]

7 minutes ago, Catacol said:

Dec phase 8 would have been much better... phase 7 was transition to high lat block, but amplitude fell away. Dont think much will come of this.

I think your more technical than i am on MJO, but on this occasion  i think your wrong

I think we have enough from phase 7 and the little weak phase 8 to bring something wintry, not widespread snow but more than a little back ed ged stuff and possibly to levels 100m and lower. Moderate phase 7 allowing strong Siberian high pressure to cause a blocking pattern that sends low pressure South East across the UK. I admit its not going to bring the perfect conditions that would be a very strong Siberian high that brings Easterlys to the UK thou,

Perhaps i am reading your post wrong thou, and its the Easterlies that you mean when you say a poor performance for cold as yes it does not look to bring that kind of deep cold

[igloo]

poor looking GFS this evening with everything moving further north as you would expect as you get nearer the time no signs of any cold with charts like this it just looks like its going the same way as the past three years and we are chasing fantasies once again

 

 

 

[SilverWolf]

Poss of topic and apologies if so, but in my memory (I’m 41, so childhood memories..) the last few weeks and what the models are showing reminds me of the early-mid 80’s. I remember a fair few rain to snow events, and milder bits, before and around christmas then something a little more substantial for cold at various times jan/feb. Does this ring true for anyone else with better memories or actual statistics? Just curious about any similarities between then and now/rest of winter, model related or anecdotal. Thanks, if bettter asked elsewhere let me know! 

[sebastiaan1973]

Catacol, your comments about the MJO reminds me of this research http://onlinelibrary.wiley.com/doi/10.1002/2017GL072832/abstract

[mulzy]

GFS FI quite interesting...

Just for fun for now!

[chrisbell-nottheweatherman]

19 minutes ago, igloo said:

poor looking GFS this evening with everything moving further north as you would expect as you get nearer the time no signs of any cold with charts like this it just looks like its going the same way as the past three years and we are chasing fantasies once again

 

 

 

Wouldn't one of those secondary lows to our west be likely to have back-edge snow on it?  To me, the jet appears to be a fair way south in that output, or am I mistaken?

[igloo]

the problem is if we keep seeing charts like this for the north east of the usa its bad news for us and has a knock on effect with little signs of it moving for the next fortnight at least not good

 

[pyrotech]

17 minutes ago, SilverWolf said:

Poss of topic and apologies if so, but in my memory (I’m 41, so childhood memories..) the last few weeks and what the models are showing reminds me of the early-mid 80’s. I remember a fair few rain to snow events, and milder bits, before and around christmas then something a little more substantial for cold at various times jan/feb. Does this ring true for anyone else with better memories or actual statistics? Just curious about any similarities between then and now/rest of winter, model related or anecdotal. Thanks, if bettter asked elsewhere let me know! 

It does in deed, i might have a look at some old charts for comparison, I know as Brecon beacons used to get back edge snow and would rarely  go more than a day or so with the last snow drifted in a ravine, before next snow fall, its been similar this year for first time in 25 years. We also see similar pattern with backedge snow. 

There was an interesting theory about a mini ice age in 2030 on sky news today regarding magnetic waves from the sun,  i currently only understand the sun spot cycle. 

Models are throwing up some interesting weather towards NYE and beyond into fi

It used to be said in 70s and 80s when USA had big snow we get it 10 - 14 days later, that not happening yet but i wondering if that was MJO related

[Ali1977]

6 minutes ago, mulzy said:

GFS FI quite interesting...

Just for fun for now!

Yes Mulzy, decent attempt at a Scandy high for sure, hopefully some ENS support too. All I need all another pretty cold run even if it is from the W/NW with plenty of colder shots - I imagine the Scottish ski resorts could do very well from this type flow.

 

[Duane S.]

Seems to me to January 5th is fast becoming an interesting date to watch. If the jet is southerly enough, and many recent GEFS runs have been showing it (even the op flirted with the notion),  there will be a clear window of opportunity for an Icelandic wedge of sorts to form . From there the ramifications could get very interesting indeed.

[Polar Maritime]

The GFS again showing a very mobile N/W flow with plenty waves of cold air passing over the UK bringing cool/cold sometimes wintry and windy with severe gales for some especially the North. Not looking bad at all as we head into January I don't think..

 

Edited December 27, 2017 by Polar Maritime
Wups wrong Month.

[Timmytour]

6 minutes ago, s4lancia said:

Seems to me to January 5th is fast becoming an interesting date to watch. If the jet is southerly enough, and many recent GEFS runs have been showing it (even the op flirted with the notion),  there will be a clear window of opportunity for an Icelandic wedge of sorts to form . From there the ramifications could get very interesting indeed.

My 'dates to watch' bingo card now has only two dates left!!

[SilverWolf]

7 minutes ago, pyrotech said:

It does in deed, i might have a look at some old charts for comparison, I know as Brecon beacons used to get back edge snow and would rarely  go more than a day or so with the last snow drifted in a ravine, before next snow fall, its been similar this year for first time in 25 years. We also see similar pattern with backedge snow. 

Thanks for your reply, shortened quote to keep thread flowing. It’s easy to to get caught up in childhood memories to ‘create’ better prospects for more cold/snow, nice to know someone else is experiencing similar memories as perhaps being relevant. Amazing though the models can be now, maybe anecdotal stuff like this is relevant to thinking about which of the many model related outcomes in say 14 days are potentially ‘more likely’. I’ll be shot down by the scientists now no doubt! 

[Ross Andrew Hemphill]

Not really sure why people are being a bit pessimistic after this 12z. To me, it shows various snow chances for loads of us, the closest being just 36 or so hours away. 

You have to remember that you don't need -10 850s for snow and cold, and that things may have to be milder for a while before the real cold arrives.