Model output discussion - winter proper underway

[MP-R]

28 minutes ago, January Snowstorm said:

One thing always surprises me is those who look for cold even when it won't snow. I mean there's nothing to be gained by 4/5 C and cold rain. Surely it may as well be 13 and pleasant?!

I get the whole seasonal 'feel' thing but in the end of the day snow is our love not cold rain.

Regarding this evenings runs nothing much on offer right now but things can change quickly and those calling Christmas 10 days out is folly. Sunday at the earliest so still 2 days to hope for change

If one could get 13 AND pleasant then I'm sure it would be better received. Sadly though it takes some pretty unpleasant weather to get those sorts of temperatures here in winter, 9 times out of 10 involving rain and gales. 

[Guest]

Briefly (for me) some of the 18z GEFS ensemble members seem to be  exploring new meteorological boundaries. Just a handful purely for entertainment:

            Perturbation 2 at T+288                   Perturbation 8 at T+288                    Perturbation 9 at T+288                     Perturbation 16 at T+384                   Perturbation 18 at T+372  

                            

  Shattered vortex and Scandi HP         The sub 920 mb LP is back!                   A bigger Scandi HP                        Another spitting vortex         Even bigger Scandi HP + into the Arctic

There are loads of others and it's hard to find one that isn't highly unusual from D11 to D16! Now they must be on to something but I doubt if the experts know what this might be!  Seriously, the fact that we're seeing such diversity proves that the models (well at least the GFS) just cannot come to terms with the conflicting background signals. I know that @Tamara suggested a possible hybrid solution but surely not almost record LP south-west of Iceland with a blocked Atlantic and an easterly over us. Perhaps it's a case of the energy having to go somewhere and the intense lows will just deepen and then fill up in situ.  Well@feb1991blizzard will be much happier to see his easterlies reappear.

I feel that we'll see lots more volatility but perhaps nothing quite as extreme as this.

Edited December 16, 2017 by Guest
Correct typos and check charts

[Catacol]

Quick update - no change from me. SOI index now negative for 5 consecutive days suggesting Nino style forcing in place... MJO set to hit phase 7 within 48/72 hours and precipitation forecasts in the pacific sizeable enough to support indications of reasonable MJO amplitude.

 

Looking for pressure rise across Europe extending northwards as per MJO phase 7 composites in around a week (as ECM has tonight up until about 168) and then fingers crossed for the atlantic trough to angle SE underneath the block in the run up to New Year. The pitfalls have been well advertised by Tamara - too much energy firing out from the canadian trough into the northern arm of the jet would compress the pattern.... so the tug of war between the Nina background state and pacific forcing made possible by warmer waters in the western Pacific is about to begin in earnest. The bigger the amplitude the better, especially with the alaskan ridge driving polewards. High enough amplitude and the cross-polar ridge from alaska to scandinavia suggested as an outside bet the other day is possible.

Annoyingly no update in concrete AAM and torque data now since Dec 6th... which is holding back accurate interpretations of the ongoing pacific pattern. Relying on forecasts is risky - hard data is much better. As soon as that data becomes available again much more can be said with confidence. Remember - if AAM budgets fall too low and low poleward flux allows the GWO 4 - 8 orbit to sink towards 1-2-3 then be prepared for a very wet and unpleasant phase after Xmas. Best bet at the moment though is that this wont happen... IF's tweet suggesting the Met are expecting some changes to model run direction before too long backs this up. Teleconnective predictions, such as we have, continue to indicate problems for the vortex and ridging returning. 

[weathermadbarnsleylad]

1 hour ago, bobbydog said:

to be fair, the American Navy can't spot an oil tanker at 50 yards let alone what the weather is doing next week....

That made me laugh yes navgem doesn't pull a very good punch 

[weathermadbarnsleylad]

Let's just take it all run to run day by day. We are now looking at high pressure in some sort of control at the minute bringing mild south Westerlys for at least 4/5days but then I think we need to see where the high wants to go. That's the key to where we go next. In my opinion FI is at 3\4 days max at the moment so wouldnt get eat up about Christmas yet until at least Tuesday next week to have a better picture. I do hope we end up with an Easterly but I think this year we will just get northerlys thru the winter no evidence. It's just my take on things. Chin up coldies we will get what we want in the end even if it's not for Christmas.thankyou.

[MildCarlilse]

55 minutes ago, weathermadbarnsleylad said:

Let's just take it all run to run day by day. We are now looking at high pressure in some sort of control at the minute bringing mild south Westerlys for at least 4/5days but then I think we need to see where the high wants to go. That's the key to where we go next. In my opinion FI is at 3\4 days max at the moment so wouldnt get eat up about Christmas yet until at least Tuesday next week to have a better picture. I do hope we end up with an Easterly but I think this year we will just get northerlys thru the winter no evidence. It's just my take on things. Chin up coldies we will get what we want in the end even if it's not for Christmas.thankyou.

Agreed.What I find fascinating in this model thread is this...we have experts herein,who can interpret and evaluate the data the models are offering and to very great detail.I am in awe at some of the scripts from the experts.Aforesaid(s) will conclude future casts from all sources,and come to conclusions of their outcomes.However,this is not forecasting the weather,it is speculation on the models' markets.I believe pattern matching albeit less scientific has far greater reliability in the 7-10 day period than what the models and their peers are capable of at present.Let's be fair to all,we are trying to predict from chaos.Next time you stir the cream in a cup of coffee,think of the jet stream.During the last few weeks I have noted a distinct pattern with heights persisting unusually to the north west,with the added 6 day northerly being forecasted and,realised.Traditionally there has always been a reset/pattern change in the weather around 18th December in the U.K. unless the big drivers are in charge,2009/2010.The GFS had given hope,the ECM was it's biggest critic and the METO was in the middle ground,quietly confident.Where are we heading now? I refer back to the pattern change,many have seen a 'front loaded' start to winter,this is unusual and confounded some of the models until well into the reliable.I do believe the trend will be short-term real time changes which the models will only just keep up with.

[tight isobar]

Just a quick 1..

What amazes me' is the constant quote'ing of 'do not take run to run as fruition and look for the overall trend!!!

Yet with such data/dynamics/divergance' it would be a bit'crackers' not to!..

Its why we have per-suites..ie-00z/6z/12z/18z...

And thats on an, operational scale!..

The only time to reference every run 'non worthy' of decipher is when its complete cross model agree.

Its gets my goat when its flagged up not to dissect every run...when clearly every run needs just that....

And current output flags this under-argue...very well..

Each suite/and run, needs eyeballing' to the finest/micro-exact!

Edited December 16, 2017 by tight isobar

[feb1991blizzard]

Corking GEFS suite trickling out.

CPF's galore.

Mean Scandi ridge at 384.

Edited December 16, 2017 by feb1991blizzard

[Ali1977]

10 minutes ago, feb1991blizzard said:

Corking GEFS suite trickling out.

CPF's galore.

Mean Scandi ridge at 384.

Just about to mention this, snap shot here!! Some are awesome.

[feb1991blizzard]

Much better ECM - pacific ridge slicing vortex completely - this is what we need.

[Frosty.]

Looks like there is plenty of mild / very mlld weather lurking in the woodshed for the week ahead, mid teens celsius for some, a lot of cloud generally too..time to turn the heating down

Edited December 16, 2017 by Frosty.

[West is Best]

There will inevitably be some gloom around with the overnight runs, however I do urge that game is far from over for the month. The ensembles continue to show huge scatter with a significant number of cold or very cold members:

18z:

0z:

There is a hint at T240 of the ECM of something interesting:

[Frosty.]

14 minutes ago, West is Best said:

There will inevitably be some gloom around with the overnight runs, however I do urge that game is far from over for the month. The ensembles continue to show huge scatter with a significant number of cold or very cold members:

18z:

0z:

There is a hint at T240 of the ECM of something interesting:

I'm really looking forward to the big plume of milder air shown on the 00z runs, I was extremely worried / concerned about how the December daffs were struggling during the cold icy weather but it looks like they will be making a great recovery during the week ahead with temps for some areas rising into the low to mid teens celsius range, especially during next midweek period..enjoy

Edited December 16, 2017 by Frosty.

[Weather-history]

58 minutes ago, Frosty. said:

Looks like there is plenty of mild / very mlld weather lurking in the woodshed for the week ahead, mid teens celsius for some, a lot of cloud generally too..time to turn the heating down

Don't see mid teens, at the moment. Teens are 13 to 19, so mid teens would be around 16C. Don't see that in the charts, doesn't look a classic fohn effect set up but we shall see.

[chris55]

ECM 192

"I feel a disturbance in the force Luke"

ECM perhaps sniffing a pattern change, the Atlantic conveyor wobbles.

[Daniel*]

4 minutes ago, chris55 said:

ECM 192

"I feel a disturbance in the force Luke"

ECM perhaps sniffing a pattern change, the Atlantic conveyor wobbles.

I feel it too.  

It’s quite remarkable how persistent +ve heights have been over the pole. ECM takes Pacific ridge to a new extreme could be quite influential on our weather, not just CONUS. 

 

[Frosty.]

24 minutes ago, Weather-history said:

Don't see mid teens, at the moment. Teens are 13 to 19, so mid teens would be around 16C. Don't see that in the charts, doesn't look a classic fohn effect set up but we shall see.

Stav Danaos mentioned 14/15c next midweek..pretty mild if you ask me!.. The Gfs 00z shows plenty of mild weather from sunday onwards, some days milder than others but sidney will be delighted with this run.

[nick sussex]

Morning all

A better start to the day for coldies than yesterday with the models playing with some different evolutions. Whilst nothing stands out within the T240hrs timeframe at least they want to displace the high to the sw further west and begin to angle the jet more se near the UK.

This comes in response to high pressure building into the Arctic from the Pacific side and some renewed amplification upstream.

At the moment Christmas Day is looking unsettled and close to average temp wise but the actual position of the jet this far out is subject to change. A southwards adjustment could develop some interest more especially for the north.

Given the re-newed upstream amplification hasn't started the downstream effects of that might take some time to feed into the outputs.

I wouldn't give up hope just yet regarding Christmas Day.

 

 

 

 

[blizzard81]

Ecm op much better this morning. The thing I like most about it is that there is much more room for improvement when looking at the northern hemisphere profile. I couldn't really say that after the previous few ecm runs. 

[swfc]

1 hour ago, Frosty. said:

I'm really looking forward to the big plume of milder air shown on the 00z runs, I was extremely worried / concerned about how the December daffs were struggling during the cold icy weather but it looks like they will be making a great recovery during the week ahead with temps for some areas rising into the low to mid teens celsius range, especially during next midweek period..enjoy

Have to say this morning im a bit confused why folk arnt a bit upbeat after yesterday's shambles

Ecm very close be it late on to a great run and a good upgrade on gfs.imo I think today will continue to improve things on the nhp and ens sorry frosty that was in reply to wib 

Edited December 16, 2017 by swfc

[chris55]

13 minutes ago, Frosty. said:

Stav Danaos mentioned 14/15c next midweek..pretty mild if you ask me!.. The Gfs 00z shows plenty of mild weather from sunday onwards, some days milder than others but sidney will be delighted with this run.

Looks like a real change, we'll certainly feel it!! Variety is the spice of life eh, as long as it doesn't last all winter I'm quite looking forward to the mild week. 

[Dennis]

give me hope

[blizzard81]

A big improvement on the ecm debilt ext ens. Many more cold runs compared to last night's scrooge suite. 

 

[nick sussex]

Reading todays NOAA update it looks like we will see a lot of energy thrown into the Atlantic between the cold air plunging south into the northern US states and high pressure over the se with moist air heading ne.

.OVERVIEW...

MODELS/ENSEMBLES ARE IN GENERAL AGREEMENT THAT THE LARGE SCALE
PATTERN ACROSS NORTH AMERICA WILL BECOME MORE AMPLIFIED OVER THE
NEXT WEEK. STRONGLY NEGATIVE HEIGHT ANOMALIES JUST NORTH OF HAWAII
WILL HAVE DOWNSTREAM EFFECTS OF ONCE AGAIN AMPLIFYING A RIDGE JUST
OFF THE NORTH AMERICAN WEST COAST (NORTH TO THE ARCTIC), WITH
TROUGHING PREVALENT ACROSS THE CENTRAL U.S. IN SOME WAYS THIS
SHOWS SIMILARITIES TO THE AMPLIFIED PATTERN EXPERIENCED ACROSS THE
CONUS IN RECENT WEEKS, BUT A STARK DIFFERENCE THIS TIME SEEMS TO
BE THE WESTERN ATLANTIC SUBTROPICAL RIDGE ATTEMPTING TO BUILD INTO
THE SOUTHEASTERN STATES. THIS PATTERN WOULD FAVOR A PERSISTENT,
SHARP, AND WAVY BAROCLINIC ZONE FROM THE SOUTHERN PLAINS INTO THE
GREAT LAKES AS ARCTIC AIR IS ABLE TO PLUNGE SOUTH INTO THE NORTH
CENTRAL CONUS WHILE COINCIDENTALLY, WARM AND MOIST AIR FROM THE
GULF OF MEXICO SPREADS NORTH INTO THE LOWER MS VALLEY AND
SOUTHEAST.
 

The issue is the track of the jet into the UK. The reason for my surprising hope for Christmas is the re-emergence of some pressure rises to the ne.

It maybe that the Atlantic is just too strong and we can't get enough trough disruption near the UK however this type of ECM spread isn't the worst I've seen.

As you can see the main spread to the west and south which indicates that more se jet track with some energy disrupting se.

So for the timebeing I'd wait to see whether this gathers pace and whether we can get enough pressure rises to the ne to get the UK on the polar side of the jet.

 

[Nick F]

Pretty impressive arctic high on the 00z ECM

I do think the models are underestimating the effects of the –EPO (which is tanking through the floor) + the effects from the MJO wave through phases 7/8 which combined will enact big poleward warming on arctic at 500mb and above into the lower stratosphere.

Mid-upper tropospheric and stratospheric forecasts have consistently signalled for major warming over Canada /Alaska side of the arctic which eventually warms the whole of the arctic above the boundary layer. The stratospheric PV is already displaced off the pole from recent warming on Canadian side and although shows signs of seasonal cooling/strengthening on forecasts, still looks in a more weakened state than is usual for the time of year.

 But onto the model guidance, I do sense that they could be programmed with an overriding ‘La Nina’ code that seems to be trying to default the runs into producing patterns typical of Nina climatology towards/into low res – i.e. –EPO ridge, SW-NE aligned trough over N America above as SE U.S. ridge then downstream a zonal flow across the Atlantic and Europe as Canadian tropospheric PV extends east over far N Atlantic and Greenland.

 However, do the models factor in the nuances of a MJO wave stuttering and stalling before heading through phases 7 and 8, which they are now only recently beginning to pick up on – along with the background of –QBO, downwelling / coupling between stratosphere and troposphere? Sometimes I think there are limitations to model guidance in that they are only as good as how they are programmed and the data that’s put into them and given they are not, as far as I’m aware, run with analogue data, exposes them to increasing margin of error when there is conflicting signals, such as La Nina against –QBO and coherent and amplified MJO, increased strat-trop coupling.

 I’m not saying for one moment that we should ignore model guidance and that they will suddenly change from the strong +NAO look to bring as HLB and winter nirvana for coldies, but it maybe worth considering, given the background signal of –QBO, fall of solar activity toward 3 year minimum and the current forecast major warming aloft of the arctic driven by highly anomalous –EPO ridging to the pole and MJO divergence aloft, that the models may start showing some effects from the arctic warming on the mid-latitudes – by forcing the cold pools and vortices out into the mid-latitudes. ECM/EPS has indicated expanding polar high pushing low heights south, which in turn, pushes the jet and storm track over N Atlantic on a more southerly track, which may eventually open up the door for HLB over Greeland, Svalbard and Norway.

But it maybe a slow process, so we may not expect to see the fruits of the arctic warming until the New Year. We could see a spell of quite stormy weather between Xmas and New Year, if the jet starts to track more south as indicated by extended EPS/GEFS.