Model output discussion - mid January

[mb018538]

2 hours ago, East_England_Stormchaser91 said:

It's that persistent cold pooling over Canada yet again that's throwing the constant curveball at us. It's barely moved all winter. 

I'm sorry, but the idea of eastern Pacific ridging only diverts the polar vortex to sit very stubbornly over NE Canada as the jet becomes rampant and digs down SE over the states and roars up the US east coast. I'd be more confident of us getting the cold with a Siberian placed main PV. The Azores high has also made sure of us missing out on easterly/northeasterly shots too. Unless we see that Canadian vortex removed and low heights over the Azores too, any chance of a classic spell will start to wane. 

As we approach solar minimum, I'm getting confident however that we will see something terrific maybe in one of the next few up and coming winters. 

This is what I've been nagging about all winter...



So long as that lump of the PV keeps sitting there (as it seems to pretty much all of the time), it'll keep unsettling the apple cart by pouring super cold air off the eastern seaboard to clash with the tropical air coming up from the south - ramping up the jet and sending deep lows our way across the Atlantic. Still chances to grab something good out of winter, but with all output pretty much excluding the first week of February from anything wintry, we are only going to have about 3/4 weeks of true winter left.

[Chesil View]

An interesting period of  model watching and hopefully weather coming up in the next 3/4 week or so I think. The GEFS and the ECM/EPS means give cause for hope from cold and snow lovers.  As we head towards the end of meteorological winter hoping for another 47 or 63 becomes less of an interest but a 2 week cold spell with copious snowfall is still not out of the question and if we could get one that spread the snow around to some of the parts that didn't get it in Dec and Jan then many on here would say overall that it had not been a bad winter and certainly better than the last few..

A point about the fab winter synptics that have been showing in the longer range on the gfs.  In my twenty years of model watching on the internet I have only ever once seen a cold and snowy spell countdown consistently from 300+ to T0 and that was late Nov /Dec 2010. All the others flashed up in FI then waxed and waned or sometime disappeared completely only to return in the closer time frame.

So reacting too negatively to the 4 times a day operational output  from the GFS is really not worth it. The suites should always be viewed as a whole which means the ens as well and even these will wax and wane in terms of numbers of cold/snowy runs.

The main thing as we head into Feb is that the main drivers are looking more likely  to give more amplified solutions as we move forward which  probably gives us a better chance of getting one of the recently shown winter wonderland outputs to verify at some point. In fact we probably have a greater chance of that outcome than we have had all winter. 

So my suggestion is similar to Tamara's don't turn yourself inside out with every twist an turn of GFS operationals at 240 and beyond because that way madness lies.

The bigger picture is the best we,ve had going forward for a long time, yes its still partially hidden but let it unfold and you may well be very pleasantly surprised

[inghams85]

Good to see people talking lag times of the MJO GWO. Nick F' s post was bang on the money. Even my own opinion of the 9th was probably on the optimistic side of the lag effects of the AAM state. Guys be patient. The eye candy was just a bonus  (might not feel like it) but the deep cold is definitely not off the menu we have a strong chance of ending this winter with a bang

[ACCOUNT DELETED]

ECM shows a ridge of high pressure across the UK & Ireland on Tuesday, low pressure returning Wednesday bringing colder air in northern & central areas but staying milder in south. Friday northerly winds but sheltered parts of southern England and South Wales could stay dry and sunny. Next weekend that high looks to be remaining close to SW UK and becoming milder again. 

Thankfully GFS 6z show rainfall totals in the SW expected to be much less than recently during the next 5 days 

Edited January 27, 2018 by Draig Goch

[beng]

1 hour ago, Matthew. said:

Thank you for all the respectful yet differing viewpoints from Nick F, Steve M, Tamara. Makes for fascinating reading and the difficulties of long range forecasting. I wonder if the Sst anomalies over in the Nw Atlantic are adding to the lows sweeping out of the Canadian side?

The SST anomalies have become slightly more favourable for cold in W Europe since the beginning on the month IMHO. Waters to our SW have cooled, but remain elevated further West. If anything I'd expect that to increase the changes that the azores ridge may be centred further westwards on average through Feb; that should allow any troughing that occurs to our East a better chance of backing west.

Plenty of fuel off the US/Canadian coast for developing deep lows though (as you allude to) so SST by no means perfect.

 

 

[East_England_Stormchaser91]

15 minutes ago, mb018538 said:

This is what I've been nagging about all winter...



So long as that lump of the PV keeps sitting there (as it seems to pretty much all of the time), it'll keep unsettling the apple cart by pouring super cold air off the eastern seaboard to clash with the tropical air coming up from the south - ramping up the jet and sending deep lows our way across the Atlantic. Still chances to grab something good out of winter, but with all output pretty much excluding the first week of February from anything wintry, we are only going to have about 3/4 weeks of true winter left.

Exactly! What we need is this, as opposed to the current theme.

[bobbydog]

9 minutes ago, inghams85 said:

Good to see people talking lag times of the MJO GWO. Nick F' s post was bang on the money. Even my own opinion of the 9th was probably on the optimistic side of the lag effects of the AAM state. Guys be patient. The eye candy was just a bonus  (might not feel like it) but the deep cold is definitely not off the menu we have a strong chance of ending this winter with a bang

ideally, we want the "eye candy" to verify, then if the MJO lands favourably, it should/could extend the (potential...) cold spell and our patience this winter will be generously rewarded. 

[MR EXTREMES]

1 hour ago, feb1991blizzard said:

Definite downgrade on the 2 GEFS suites since 18z and there is no point dressing it up any other way, I think we need to accept that earlier suites were too early with any potent Easterly and just keep fingers crossed on the D13-16 parts of the suites for the next couple of days.

I agree fair to say it's been another wild goose chase.

Still bit of time for February to show something special but with Nina still very much dictating the atmospheric chaos.

We need the vortex to either relocate or a full reversal and this seems unlikely.

I threw the towel in ages ago but that's not to say it's not been a close call.

butthe GFS has been consistent with its more westerly flow with flattening of Atlantic ridge with unsettled cooler further north.

South generally more settled dryer to.

Actually all models have backed of the eye candy shown.

Extremely frustrating but not a surprising.

JMA looked beautiful a few days back but has now joined to ECM and GFS on backing away from anything other than a pretty bog standard start to February.

Ao beautifully negative.

But nao reflection of vortex fighting hard with strong jet stream with deep lows constantly running along to our north.

I also don't see any chance of Scandinavia block or Greenland block.

Over all disappointing I really do believe it's unlikely we will see anything with la Nina and Azores and strong jet stream all working against blocking.

Toppler is the word of February.

 

[beng]

2 hours ago, Steve Murr said:

This winters got 3-4 main weeks left & then it’s over for another year, whist we have been lucky in certain locations the headline figures will be yet again no SSW which makes it what 7-8 years -

probably no deep cold from the continent ( although there is still time ) 

No Greenland high - when was the last time we saw that & an above average winter...

We will be very very lucky if things work in our favour now..

just for a moment think of every single excited outlook / forecast & model run since the last week of November - & there has been hundreds from all quarters NOT 1 SINGLE DAY OF THIS WINTER HAS RECORDED A NEGATIVE NAO

The Atlantic SSTA were absolutely terrible for cold at the beginning of the winter - I posted something in the winter thread during (in Nov or Dec) about them being the polar opposite of Nov 1962 so it's been interesting to watch things play out. Even though we've had no negative NAO, it's been a reasonable winter I in Scotland and the midlands have done okay too - so could have been worse. 

Crap here though.  

I think the 'atmosphere' has been better suited for cold this winter than the previous couple, but the Atlantic SSTs have fought that signal all the way.  We should be in a much better position (my opinion only) from an Atlantic SST position when we start next winter as the solar minimum begins to take hold and the AMO cools a bit more, although the QBO will then be against us.

I think we'll actually get one decent cold shot during Feb - based on the MJO cycle (which I admit is based on a model forecast that could be wrong) and the sheer amount of surface cold over Russia now: 

- starting 8th-10th Feb is my prediction (similar start point to the 1991 - won't be on the same scale as that one though (probably).

[Chesil View]

25 minutes ago, inghams85 said:

Good to see people talking lag times of the MJO GWO. Nick F' s post was bang on the money. Even my own opinion of the 9th was probably on the optimistic side of the lag effects of the AAM state. Guys be patient. The eye candy was just a bonus  (might not feel like it) but the deep cold is definitely not off the menu we have a strong chance of ending this winter with a bang

Good post Inghams85 . Being of a late middle aged vintage I can remember very well the cold spell and sensational southwest snowfalls of Feb 1978, here in Dorset but it wasn't really until the 7/8th Feb that year that it became obvious what was about to happen cold wise just a few days later. The two heavy snowfalls on the 15th and 16th followed by the great southwest blizzard were just the icing on the cake.. .. Amid feb cold spell and copious snowfall are still possible.  Could it be that this winter saves its best for last.

[Daniel*]

P20 is a thing of beauty Steve M sausage? The 5th keeps cropping up I notice outside chance of much colder conditions week 1, -12C isotherm is there from T+228 all the way to end at T+384 severely cold 

[SMU]

1 hour ago, jvenge said:

I appreciate the irony of you appreciating the irony. You literally just celebrated the fact the other data source was pulled and then quoted another message also mentioning the fact the data source was pulled. Thus leaving only GEFS output to post? Erm.

MJO data still available from all models. Not that it was the full picture anyway. GEFS still better than nothing.

People are forgetting lag times. There wasn't going to be a Scandinavian high so quickly. Even if everything goes to plan from today onwards (GEFS showing a phase 4 GWO now, actually in already, not talking forecast), that would be at least 10 days away, probably nearer 15. From today.

 

Here’s a poser then

the GFS for a day or 2 had a Scandi high well before your lagged time - A model doesn’t forget things - so unless it was being progressive by 10 days / 2 weeks then it goes against what your indicating..

so vis a vee at that point the MJO was necessary driving the GFS output-

 

in terms of GFS being the only data source available for some quite important plots that’s like school kids taking turns picking their football teams & the GFS being the last one picked because it had to be picked- doesn’t make it any good-

Edited January 27, 2018 by Steve Murr

[Singularity]

2 hours ago, bluearmy said:

I think the issue with the MJO plots is the lag re patterns establishing this side of the NH. There must be a good 5 to 7 days to get the patten over the east Atlantic reflective of the MJO analogue. the models are showing a trop that seems pre disposed to amplification at the moment. But seems tough for this to sustain with the Canadian vortex spewing out pulses of low heights every few days. the fact that we know glosea and ec 46 are both ridgy to our east by mid Feb is notable. Anything before that remains unreliable and given the range, those tools are always suspect. I think the end of last jan saw us chasing a scandi ridge as the strat vortex showed a sudden drop to almost ssw territory. We aren’t in the same place this season stratwise but we are still chasing the scandi ridge! 

I have been wondering whether the analogue plots actually show what tends to be happening after a lag time as opposed to just what tens to be happening while the MJO is within the given phase.

The latter case would mean that what we see as a phase 7 composite is actually a combination of phase 6 after typically 4-6 days lag and little MJO influence at all (cases when the MJO was weak in 6 but strengthened in 7).

That sounds inefficient so intuitively the expectation is that some manner of lag is being factored in - but this is not guaranteed unless someone can find information on the methodology behind the plots?

 

Anyway, in the 6-12 day period the main questions revolve around how much the rising GLAAM tendency can adjust the positioning and movement of the deep cold over N. America; can it do enough to turn an eastward cold air spillage into the N. Atlantic into a SE/SSE'ward plunge that gives rise to a deep but slow-moving or stalled-out LP system that amplifies the downstream pattern?

GLAAM set against the GWO enables interpretation of what model outcomes should be taken more seriously than others. At times this is easily done; when GLAAM is resolutely low as it was earlier this month, or high as it was a couple of winters back. During times like we have now though, when GLAAM is being forced upward but against a background that would rather this was not the case, and with uncertainties regarding the relative strength of the forcing mechanisms involved, then there is indeed more of a 'wait and see' nature to the assessment - but we do at least know that a change is trying very much to manifest for our part of the world. So we might as well cross our fingers?

[inghams85]

39 minutes ago, bobbydog said:

ideally, we want the "eye candy" to verify, then if the MJO lands favourably, it should/could extend the (potential...) cold spell and our patience this winter will be generously rewarded. 

I agree! That would be incredible but the chances are diminishing of getting anything from the EPO ridge

[inghams85]

26 minutes ago, Broadmayne blizzard said:

Good post Inghams85 . Being of a late middle aged vintage I can remember very well the cold spell and sensational southwest snowfalls of Feb 1978, here in Dorset but it wasn't really until the 7/8th Feb that year that it became obvious what was about to happen cold wise just a few days later. The two heavy snowfalls on the 15th and 16th followed by the great southwest blizzard were just the icing on the cake.. .. Amid feb cold spell and copious snowfall are still possible.  Could it be that this winter saves its best for last.

That's just before my time I'm afraid! (Born 1985) but in my lifetime all the best cold spells have been in February! The cards look stacked in our favour though certainly mid feb!

[Paul]

25 minutes ago, Steve Murr said:

In terms of GFS being the only data source available for some quite important plots that’s like school kids taking turns picking their football teams & the GFS being the last one picked because it had to be picked- doesn’t make it any good-

It doesn't make it automatically rubbish and not work looking at either though. The way forward is surely to use all the data that's available and try to make a balanced judgement, not to arbitrarily throw bits away.

[SMU]

25 minutes ago, Paul said:

It doesn't make it automatically rubbish and not work looking at either though. The way forward is surely to use all the data that's available and try to make a balanced judgement, not to arbitrarily throw bits away.

No - but your left in the position of thinking hum what elements can be trusted if any-

whats more likely to fail & so on- & that brings us back round to where we have always been with the NWP @ day 6-8..

nothing much has really changed in the last 10 years-

Edited January 27, 2018 by Steve Murr

[bluearmy]

Fwiw, the anomoly at the back  end of the gefs 06z looking like the eps at that stage as the low heights from the nw begin to undercut the developing ridge to our east 

[offerman]

With regards to the charts = forecasts = accuracy and best thread forecaster.

Hi all, 

Would it be possible to build a table of the most accurate forecaster on this thread and what the best charts most accurate charts have been over say he last Ten years or so.

Then focus on those areas and build collate extra data to see if these get surpassed to try and build up an analytical pattern legacy results.

Then perhaps make a league table of the most accurate charts to certain types of weather, then corresponding sun spots/solar flares/ Ferrell Cell / Volcanoes above and below sea level, if great under water eruptions occur then this surely must have an affect on water temperatures locally and maybe on a wider scale during larger magma quantities. Some of this heat making its way to the surface albeit diluted due to surrounding cold but sure these changing must have an effect of some kind. so many factors and many i probably have missed but if a database could be created somewhere and add in the above said points mentioned then maybe a slightly more reliable pattenr translating in to forecast for coldies could be possible although will never be bang on accurate but with a goal of maximising forecasts.  GFS lets evryone down with amazing cold charts and 99/100 gets watered down or just doesnt evolve as too far out .

[ArHu3]

2 hours ago, East_England_Stormchaser91 said:

As I've said, continuous ridging of heights in the NE Pacific is almost certainly to blame. I would like to see this totally gone next winter and see a different approach from the jet stream across the US, instead of it being supplied with rocket fuel along the eastern seaboard. We need it to dive down SE out of the states instead of parallel along the coast heading NE, not only to have reduced power, but to displace/replace high pressure over the Azores with a deep low. This would then leave room for heights to develop around Greenland and to get the proper omega style high in place up there instead of repeated failed ridging that ends up being a mediocre toppler. 

If you look at the likes of the real true snowfests of 78/79, 62/63, 46/47, the charts for back then clearly showed what I have mentioned above. All of them had absence of the Azores high. 

 

That is not really always true, eg a week before the 63 coldspell began there was a huge azores high and 79 saw huge pacific highs. Looking back at winters past what is quite noticeable is a much greater piece of vortex in Siberia and or Alaska, I have no clue why the vortex moved, perhaps it's the loss of sea ice and/or the greater snow cover in Siberia? 

[ArHu3]

1 hour ago, Singularity said:

I have been wondering whether the analogue plots actually show what tends to be happening after a lag time as opposed to just what tens to be happening while the MJO is within the given phase.

The latter case would mean that what we see as a phase 7 composite is actually a combination of phase 6 after typically 4-6 days lag and little MJO influence at all (cases when the MJO was weak in 6 but strengthened in 7).

That sounds inefficient so intuitively the expectation is that some manner of lag is being factored in - but this is not guaranteed unless someone can find information on the methodology behind the plots?

 

Anyway, in the 6-12 day period the main questions revolve around how much the rising GLAAM tendency can adjust the positioning and movement of the deep cold over N. America; can it do enough to turn an eastward cold air spillage into the N. Atlantic into a SE/SSE'ward plunge that gives rise to a deep but slow-moving or stalled-out LP system that amplifies the downstream pattern?

GLAAM set against the GWO enables interpretation of what model outcomes should be taken more seriously than others. At times this is easily done; when GLAAM is resolutely low as it was earlier this month, or high as it was a couple of winters back. During times like we have now though, when GLAAM is being forced upward but against a background that would rather this was not the case, and with uncertainties regarding the relative strength of the forcing mechanisms involved, then there is indeed more of a 'wait and see' nature to the assessment - but we do at least know that a change is trying very much to manifest for our part of the world. So we might as well cross our fingers?

Anthony masiello and Sam lillo often post beautiful animations of waves originating in the tropics propagating and breaking, my guess is that is what the models try to calculate, these waves in the atmosphere 

[Mucka]

God bless this forum and all who sail in her.

No matter what our Winter weather brings we can always guarantee cold snaps, storms and hot air here.

And yes I most definitely include myself in that.

Cold signal has been wavering today but is still there, nothing some good Op runs won't put right though.

 

 

 

[Chesil View]

1 hour ago, Daniel* said:

P20 is a thing of beauty Steve M sausage? The 5th keeps cropping up I notice outside chance of much colder conditions week 1, -12C isotherm is there from T+228 all the way to end at T+384 severely cold 

Yes Daniel that really is a corker. Very 47 esque.

[tight isobar]

Oh-dear-oh-dear -oh dear!!!

Will some not equate, to the fact as mentioned by myself/and others many times of late...

That exactly the reverbs-model miss-dynamics are 'bound'..

Nina/mjo forcing..and hem-situ are as stark as they can be for model miss-managment!!..

Its un-tieing the knot of a massive tangle.

Bur the signals and raw out should be the note.

We are in a very steady state(beleive or not)..

For some great dynamics and infer for the best..perhaps most notable spell-of certainly this winter...and maybe those past..

I'll elaborate later on to my deciphers on all above...and hope to shovel out the confusion.....

[snowbunting]

My thoughts are there is still alot of uncertainty from next week onwards. I still fell the NW flow will rule..the ensembles . From around the 2nd of feb, really show this.