Model output discussion - 21st Jan Onwards

[nick sussex]

Still quite a few different solutions at T120hrs in the ECM postage stamps:

http://old.ecmwf.int/samples/d/inspect/teasers/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!120!pop!od!enfo!enplot!2016012912!!/

The track of that Greenland low which drops se still open for changes. Theres also some support for a shortwave running close to the south of the UK like the earlier Arpege run.

[Allseasons-Si]

1 hour ago, johnholmes said:

The NOAA anomaly charts show how the colder spell is going to develop, cannot show links but easy enough to find. If desperate look for my posts 2 weeks ago for the links!

All being well back to normal posts from Sunday

 

Just looked at them john,are you refering to the disconnect of the atlantic there?,pressure to the north and ridge in the atlantic so the only way the trough will head is SE,looks that way to me

looking at the latest models,it does seem that everything is going to be thrown into the mix including the kitchen sink in the next 7-10 days,

temps slowly coming down now so hopefully we will all get there in the end,we have been waiting for soooo long now

00z12z

some back end snow 5th feb maybe?

and to add,the warming at 10 hpa is more prevailant on the 18z

12z @ 25218z @ 240

Edited January 29, 2016 by Allseasons-si

[BLAST FROM THE PAST]

1 hour ago, lukemc said:

BFTP by impactful weather do you mean snow potential? I suppose it could mean wind but that low does not look that deep to me so maybe you were talking about snow potential.  Things do seem to be getting colder what do you think do you think we are in with a good chance of a good snow event in the next 2 weeks hopefully the SSW will help.

 

Luke 

I mean disruptive, and I think snow will be a part of that disruption with a risk for all the Uk....but not at same time of course.

 

BFTP

[TomDav]

52 minutes ago, Allseasons-si said:

and to add,the warming at 10 hpa is more prevailant on the 18z

12z @ 25218z @ 240

Although there is no split on the 18z

12z  18z 

Hopefully there will be improvements in the morning

[Jason M]

GEFS out to 240. If there is a cold spell coming I certainly can't see it. A few look okay at face value but of course in such a mobile pattern the 850s are not supportive of anything much. In terms of wintry weather IMHO the absolute best we can achieve is something akin to tonight  with snow on high ground and in Scotland.

 

 

Edited January 29, 2016 by Jason M

[Daniel*]

Disagree Jason,

Wednesday looks rather interesting up & down the country.

A disturbance in the flow moving down the country 500mb temperatures below -35C ideal for polar low development, I think it is a polar low...

much of the country seeing snowfall even in S. Quite marginal with 850's.

Edited January 29, 2016 by Daniel*

[lorenzo]

Keep onboard, its coming

Torpedos - so misaligned perception, GP spot on really, lagged effects are perfect..

NWP modelling - hints of fun.

Winter forecast for NWx.

Well we did it and it's played per plan, no. doubt. February - okay give us the cold strato. no one will complain, but will it.

Analog central for West based  NAO pulling in but hey I don't actually care if it goes off here, if we get this wrong at 135 days out then am not worried 

 

Especially if this delivers cold for those looking.

[Jason M]

2 minutes ago, Daniel* said:

Disagree Jason,

Wednesday looks rather interesting up & down the country.

A disturbance in the flow moving down the country 500mb temperatures below -35C ideal for polar low development, I think it is a polar low...

much of the country seeing snowfall even in S. Quite marginal with 850's.

Fair enough. 

my observation on those charts is that to get meaningful snow for much of the country you really need theta values of 10 or less. The GEFS snow predictions usually over egg things dramatically. I'm sticking to my prediction of nothing untoward. Snow over high ground in northern England and maybe some wet stuff to lower levels in Scotland. 

We are essentially looking at a heavily modified PM airmass. Nothing for most to excited about IMHO, albeit with altitude some might get lucky. It's just bog standard winter weather really.

i suppose the proof one way or other will come after the event. 

[lorenzo]

10 minutes ago, feb1991blizzard said:

I remember thinking at the time that it wouldn't take a massive deviation from your forecast for a cold February.

It's a good point and back in October, one that Ed and I debated somewhat.

For those of you wondering i want to reinforce that the reference is without any question indeed October.

This is born from the analogs, the stratospheric bridge that created those analogs, the QBO, the BDC, the transport expectations and much more.

Much more a la the Nino standing wave and various MJO imprints throughout this winter

Leading the MHO is the GWO oscillation and on a very basic view, one that I enjoy, is whether the atmosphere rolls up, more blocking, or rolls down, more Nina elements, more flow, less blocking

This year is nothing short of spectacular for pitching both head on.

1 we have an uber cold vortex delivering unknowns in analogs for the stratosphere in respect of feedbacs when wave breaking evolves/

2 we have an anomalous Kara Ridge establishing from late December as a classic atmospheric Block. We all love Blocking we have looked fondly on blocked patterns many a time. This ridge though formed directly beneath the peak zonal wind analog in the stratosphere, we have the strat. buzzing at full cold tilt reaching climatalogical obscene levels and yet this once in 24 yrs Kara Sea ridge maintains

 

Result - extraordinary season where on the best analysis we have we see the huge disconnect between stratopsheric evolution and any other mode.

 

I say any other mode as MJO / GWO / Nino Imprint from what is canonical in analog years - this is not replicated for the 15/16 winter.

 

So where are we now?

1 honestly, beyond my knowledge, am not a scientist, have learned lots here but suspect we are into a mode beyond one that is currently known.

2  working idea, we have a mesospheric signal related to EPF that resides in the upper stratosphere, this mode then downw ells over a time at varying particle efficiency to create an atmospheric mode. This mode is not quantified due to lack of resource in atmospheric monitoring, however even without it, this mode can identify the faults in other theories based around the standard solar cycle.  The solar 11 yr cycle not successfully moving on from the base mode of historical inflect.

 

Outcome

Oour stratospheric monitoring hides another mode, one that is informed by solar flux and has a cycle that originates in the mesosphere, the evidence of this mode will be delivered by re analysis of the design of the QBO.

 

[lorenzo]

Hey @blizzard81 hope the other post explained, long week for me too !

Anyhow in a nutshell...

1 In October Ed and I identified possible SSW window.

2 At same time binned cold analogs ( huge 10hPa displacement Dec /Jan )and went with instinct ( hence references to NW Forecast)

Hopefully I explained more in subsequent post, sorry if not !

Interesting point here is the stratospheric connection to El Nino and whether this actually has an effect.

 

In a year with a massive El Nino, okay so that's an understatement already, the biggest basin wide El Nino ever witnessed..

Then, 

We have grounds to examine the impacts of the trop on the strat. We have grounds to look at this Nino and tropical excitation of the stratosphere.

This was one of the key elements of our forecast, did I mention we wrote it in October...

So, here we are in Feb, or atleast model out put looks to Feb.

1 SSW hasnt happened.. moan moan - well it did happen as far as wave dynamics are concerned, you saw on boxing day the most impressive P2 ACW break in history.

2 Why no SSW - uber vortex, an anomaly no one could predict.

3 Now - well we would say in forecast, back to canonical West Based hell for the NAO. Truth is hopefully something else is borne from the SSW ( yeah the one we didnt actually foresee in October) as a result of the Nino bridge( again not ever mentioned in October) sorry am being silly.

Truth told without the odd Northerly meander via MJO then winter has rolled thru as per forecast. In all honesty the only debate Ed and i had was on liit of NS divide

On hear one would have you believe micro inflections deliver UK weather, sorry - I think not.Jan so far showed cold and Feb well let's see, cannot be arsed with minute semantics. It is what it is, a forecast based on the whole season

Personally as a coldie I hope we get a surprise trop effect cold hit, otherwise will trust what I saw what is now 5 months ago and the pull through of a waning canonical nino forcing.

Edited January 30, 2016 by lorenzo
Will try to explain more coherently tomorrow !

[Mucka]

Interesting UKO this morning and the noticeable differences with GFS start early and by 120 the result is that UKMO doesn't have the Azores high nosing back thus maintaining the colder air over the UK which could produce some transient snowfall, more especially for the North . Either way I prefer it to GFS as it gets the trough further South. 

 

[Ravelin]

The thing that strikes me about those charts @Mucka is the hieghts over the pole and the generally messed up state of the PV. ECM shows pretty much the same and then maintains the same theme out to t240. 

The GFS though tends to re-energise the PV to an extent, whilst at the same time maintaining a much more robust Alaskain ridge through the run. 

[IDO]

The models are still struggling with the EPO ridge as and how the Arctic High is handled so anything after D7 is fluid. Consistency at D10 re this EPO ridge, and tghat looks to have more staying power than I initially thought. Upstream amplification is never a bad thing though with  PV lobes settling in the Atlantic region there is little hope of a sympathetic Atlantic Ridge in that period.

D10 three main models: 

Depending on where the Arctic heights are look like they will effect the orientation, longevity and placement  of any trough in our vicinity. The previous ECM runs showing good trough disruption are no longer there and accordingly any cold uppers are now warmed out. 

So a cooler flow but nothing far off seasonal expectations especially for the south. The GEFS show average temps throughout (Sunday & Monday milder) with no sign of anything but cold rain away from hills, mountains and Scotland.

London T850 and 2m temps: 

Rain again the main headline: 

 CFS w3 & w4: 

The CFS^^^has the positive anomalous heights remaining in w3 and w4 with no sign of Northern Blocking.

All this is just what the models are currently showing and with many background activities we are in a situation that the models may just flip in the next 10-20 days. The next week or so looks of little interest for anything blocked and just average winter weather. The GEFS through to D16 are still not showing anything in the way of a cold blocked pattern, with a PV lobe to our NW spawning low followed by low through the UK towards a trough east of the Azores. Mean at D16:

Edited January 30, 2016 by IDO

[Singularity]

GFS has become very inconsistent even with the stratosphere, a sign that it's trying to figure out how changes in tropical forcing affect the situation (e.g. EPO ridge). Unfortunately it had the MJO going the wrong way (toward 3 instead of 5) as of yesterday so that will be messing with things. The idea of a strat. split has yet to re-appear since the 12z, and the second displacement is failing as well, although I struggle to comprehend how given the strength of the predicted warming event.

 

Anyway, some trouble in the shorter-term this morning, as a slower, more amplified trend ends up working against us with respect to how far east the LP crossing the Atlantic gets before it stalls out and digs south. It doesn't get far enough to merge with the Scandi trough and so a UK trough becomes the dominant feature with a fair bit of rain and some strong winds to contend with.

By continuing the slowing of the jet and increasing of amplification, ECM does arrive at a promising day 10 setup. In a way the procession toward a proper northerly has been put back by around 36 hours.

GFS, thanks to both its taking of the MJO to phase 3 (La Nina type forcing) and its movement of the strat. vortex to Greenland manages to build a new Canadian vortex in the troposphere which is, to put no fine spin on it, lame.

 

UKMO's shorter-term is an interesting variation in which there is no organisation south of Greenland of the disturbances crossing the N. Atlantic, whcih retains a faster momentum eastward, resulting in those features merging with the Scandi trough. The focus of stormy weather still ends up over the UK but with less in the way of milder air thrown into the mix and perhaps a quicker route to a northerly in the days to follow.

  

 

Hah, just seen your post IDO, picking out the EPO ridge as well 

What CFSv2 is showing is a classic El Nino pattern without modification by unusual MJO activity, which may prove to be an oversight if the EC-30 has its way. Then there's the possible strat. influence, but that seems to be up in the air at the moment.

[Frosty.]

The Ecm 00z ends on a promising note for much colder prospects beyond T+240 as the large complex trough across the UK pushes away to the NE enabling arctic air on it's western flank to eventually flood south across the UK...actually it's rather cold for much of the time even before we get to that with close to 528 dam thicknesses...not mild!

[IDO]

27 minutes ago, Singularity said:

 

What CFSv2 is showing is a classic El Nino pattern without modification by unusual MJO activity, which may prove to be an oversight if the EC-30 has its way. Then there's the possible strat. influence, but that seems to be up in the air at the moment.

Yes I post the CFS just for reference as to the most likely outcome based on re-analysis. I am never going to hang my hat on them. This year as the Pros have said is a one off and the experts can use their knowledge to work out the most likely outcomes, but as we really don't know if that major SSW will ever materialise, we are hoping for the MJO later in Feb to spark a change or the trop PV to wane a bit quicker than currently predicted to enable a more meridional flow. 

I suspect the models will look more promising in a weeks time and then we can then see if the UK will benefit from any NH pattern changes.

Edited January 30, 2016 by IDO

[bluearmy]

Still looking beyond the 10th for things to potentially get very interesting. the Russian ridge seems set in concrete  and will prevent eastward movement of the upper trough too far to our East. another Arctic high appears though we know from January that modelling this, run to run with any accuracy will prove tough .  The Canadian p/v seems likely to retreat west a bit. there is an amplification in the PFJ heading east across the Atlantic.  too many options on the table to make a prediction but there are some possibly very wintry ones that could ensue from that starting point.  In any case, I would suspect the northern half of the UK at elevation will see an impressive piling up of snowcover through the month. whether we will see patterns play out to draw that down to sea level is the question.  once GFS gets a handle on the broad evolution, the 10/16 day output could be fun to watch.

[Ali1977]

Very good FI coming, WAA on its way to Greenland 

This still gets bowled over by the chunk of PV in Canada though!!

Edited January 30, 2016 by Ali1977

[Spah1]

GFS starting to smell the coffee???

[Ali1977]

2 minutes ago, Spah1 said:

GFS starting to smell the coffee???

It's smelling something in FI, not sure it's coffee though!! 

[Frosty.]

The Gfs 6z shows several attempts at a Northerly outbreak, the first attempt next week is a non starter as it soon gets flattened from the west before the cold air can become established but next weekend is a bit more successful with more of a cold dig south and then similar results from the next attempt but with leading edge snow as the Atlantic sweeps back in with snow becoming confined to northern hills but there are quite a few frosty nights on this run, especially in the north. It makes me wonder what we have to do to get a decent arctic blast in this country but I feel we are on the right track to getting one during February...I should also mention it looks like more stormy weather will hit the UK at times in the next 7-10 days, especially northwestern Britain but the 6z ends calmer and drier further south as high pressure builds in across southern areas from the near continent. There is a lot going on and for coldies there is at least more potential than we have seen so far in this sorry winter!

Edited January 30, 2016 by Frosty.

[Frosty.]

No respite from these damn storms, Gertrude is gone but the next storm, horrid Henry is sweeping in for Monday although it doesn't look as severe as Gertrude. Monday looks very mild across the southern half of the UK with max temps into the low teens celsius, more like spring than mid / late winter but temps then fall back closer to normal once Henry clears off!

[terrier]

So once again we are looking at day 10 charts for something colder. How many times has the gfs and ecm teased us at day 10 this winter. If the models are flip flopping at t144 what hope do we have at day 10. 

[ColdFront80]

I'm sure this will be Storm Henry.

[terrier]

7 minutes ago, Frosty. said:

Day 10?..it's snowing in the north today!

Maybe so frosty but that's not unusual for Scotland. And looking at the output we're all back in milder air tomorrow. With more rain and gales next week. The point I was making is these charts showing colder nationwide are always at day 10 and we always seem to be chasing that pot of gold in the charts which never seem to get any closer.