Model output discussion - 21st Jan Onwards

[Catacol]

17 minutes ago, Earnest Easterly* said:

A little patience is needed, some silly posts creeping in.

February is ripe for the taking. I'm no strat expert but the chart below shows a significant warming on Eurasia side off the scale in fact!  They do not come often

At 10hPa level on latest GFS, it would reshuffle the deck' imo.

Yes - it probably would. But the point that many have correctly made as to the strat this season is that these charts seem to remain just out of reach at the 240h mark each time. This is another long range prediction. Fingers crossed the slow burner finally gets somewhere close to ignition..

[IDO]

4 minutes ago, Earnest Easterly* said:

A little patience is needed, some silly posts creeping in.

February is ripe for the taking. I'm no strat expert but the chart below shows a significant warming on Eurasia side off the scale in fact!  They do not come often

At 10hPa level on latest GFS, it would reshuffle the deck' imo.

Are the models showing a major SSW? I thought that a minor one was being modelled? That is assuming that comes to fruition. If it is a minor one, and that is obviously better than none, then I am not sure we can expect too much from that, compared to the cold that would flood south if the vortex was smashed. Dr Cohen tweet, still downbeat:

 

 

So little sign of a strat to trop response in the next two weeks (from this run).

We are seeing a strong El Nino combined with a cold strat PV and AAM off the charts, a rare occurrence, so we are really in the dark as to how this will play out, so maybe assumptions about a cold Feb and March should not be banked, as to date nothing has really gone to expectations? Best just to follow the models and if they don't show cold, then maybe that is what happens when we get this type of background signals? 

[Singularity]

Well, GFS finds some great amplification in lower-res... but it's in the wrong place! It looks to be to me an issue of having that strong support for subtropical ridging remaining in place as the strat events impact the troposphere, basically making a large westward adjustment to the location where the jet dives a long way south. 

This is why I keep banging on about the model taking the AAM into phases 1/2. Remove that, and I expect the output would shift abruptly toward something more like ECM's 12z det. run, which makes relatively subtle, but far closer to expected, adjustments to the longwave pattern, the subtropical ridge being gradually suppressed south while the vortex starts to make itself at home over Scandinavia. 

Hopefully GFS will make that AAM adjustment soon, as I'm getting bored with its constant championing of over-inflated Euro Highs.

I expect our main headaches will come from residual low heights over Canada and how long it takes for the tropical forcing to either drive them out east, pull then back west, or a bit of both. The retrogression of the Aleutian low that's needed for a pull west is evident in the ECM 12z det. but the model vacates the low heights east instead. I remember it was a bit keen on doing that in the run-up to last year's cold spell which also involved a vortex shift to Scandinavia (but executed rather messily due to a lack of strong support from the teleconnections). It actually led to overly 'clean' transitions with high pressure springing up toward Greenland, when in reality this was not carried out well enough and shortwaves quickly broke the ridge down again before it could settle in. I believe a safer route is to retrogress the low heights in Canada in tandem with the Aleutian trough.

 

As an aside - any chance the scale on the strat. charts can be adjusted to a higher limit, admin team?

This is so far off the current scale, it's embarrassing!

If I have my facts straight, it's a consequence of having such a large, deep area of low heights over Scandinavia with the associated cyclonic flow piling into the Himalayas, driving an Asian MT which is the trigger for dramatic strat. warming. 

Edited January 22, 2016 by Singularity
typo!

[Yarmy]

11 minutes ago, Singularity said:

Well, GFS finds some great amplification in lower-res... but it's in the wrong place! It looks to be to me an issue of having that strong support for subtropical ridging remaining in place as the strat events impact the troposphere, basically making a large westward adjustment to the location where the jet dives a long way south. 

This is why I keep banging on about the model taking the AAM into phases 1/2. Remove that, and I expect the output would shift abruptly toward something more like ECM's 12z det. run, which makes relatively subtle, but far closer to expected, adjustments to the longwave pattern, the subtropical ridge being gradually suppressed south while the vortex starts to make itself at home over Scandinavia. 

Hopefully GFS will make that AAM adjustment soon, as I'm getting bored with its constant championing of over-inflated Euro Highs.

I expect our main headaches will come from residual low heights over Canada and how long it takes for the tropical forcing to either drive them out east, pull then back west, or a bit of both. The retrogression of the Aleutian low that's needed for a pull west is evident in the ECM 12z det. but the model vacates the low heights east instead. I remember it was a bit keen on doing that in the run-up to last year's cold spell which also involved a vortex shift to Scandinavia (but executed rather messily due to a lack of strong support from the teleconnections). It actually led to overly 'clean' transitions with high pressure springing up toward Greenland, when in reality this was not carried out well enough and shortwaves quickly broke the ridge down again before it could settle in. I believe a safer route is to retrogress the low heights in Canada in tandem with the Aleutian trough.

 

As an aside - any chance the scale on the strat. charts can be adjusted to a higher limit, admin team?

This is so far off the current scale, it's embarrasing! (Hah, turns out Chrome's U.S. English does not recognise embarrasing as a word!).

If I have my facts straight, it's a consequence of having such a large, deep area of low heights over Scandinavia with the associated cyclonic flow piling into the Himalayas, driving an Asian MT which is the trigger for dramatic strat. warming. 

 

Embarrassing has a double s.

ECM has been pretty consistent with shifting the bulk of the low heights over Greenland to the East, but it's all for nought while the upstream pattern remains flatter than an Amish disco. 

[Singularity]

15 minutes ago, Yarmy said:

 

Embarrassing has a double s.

ECM has been pretty consistent with shifting the bulk of the low heights over Greenland to the East, but it's all for nought while the upstream pattern remains flatter than an Amish disco. 

Cripes, shows how much I lean on autocorrect... how embarrassing 

For some reason the word doesn't come up on the list. I will correct and then this post can be deleted, mods!

 

Edit: or I could just grin and bear it, and add something on topic in response to the second line of Yarmy's post;

I don't know about you, but to me that looks well amplified over the U.S. and I expect this would propagate across to the Atlantic over the following days.

Edited January 22, 2016 by Singularity
=]

[Bob G]

1 hour ago, Singularity said:

Well, GFS finds some great amplification in lower-res... but it's in the wrong place! It looks to be to me an issue of having that strong support for subtropical ridging remaining in place as the strat events impact the troposphere, basically making a large westward adjustment to the location where the jet dives a long way south. 

This is why I keep banging on about the model taking the AAM into phases 1/2. Remove that, and I expect the output would shift abruptly toward something more like ECM's 12z det. run, which makes relatively subtle, but far closer to expected, adjustments to the longwave pattern, the subtropical ridge being gradually suppressed south while the vortex starts to make itself at home over Scandinavia. 

Hopefully GFS will make that AAM adjustment soon, as I'm getting bored with its constant championing of over-inflated Euro Highs.

I expect our main headaches will come from residual low heights over Canada and how long it takes for the tropical forcing to either drive them out east, pull then back west, or a bit of both. The retrogression of the Aleutian low that's needed for a pull west is evident in the ECM 12z det. but the model vacates the low heights east instead. I remember it was a bit keen on doing that in the run-up to last year's cold spell which also involved a vortex shift to Scandinavia (but executed rather messily due to a lack of strong support from the teleconnections). It actually led to overly 'clean' transitions with high pressure springing up toward Greenland, when in reality this was not carried out well enough and shortwaves quickly broke the ridge down again before it could settle in. I believe a safer route is to retrogress the low heights in Canada in tandem with the Aleutian trough.

 

As an aside - any chance the scale on the strat. charts can be adjusted to a higher limit, admin team?

This is so far off the current scale, it's embarrasing! (Hah, turns out Chrome's U.S. English does not recognise embarrasing as a word!).

If I have my facts straight, it's a consequence of having such a large, deep area of low heights over Scandinavia with the associated cyclonic flow piling into the Himalayas, driving an Asian MT which is the trigger for dramatic strat. warming. 

I'm pretty new at this model stuff, but if I understand it right, the stratosphere is not as dense as the troposphere so it is easier to model, something at T360 in the strat is about the same as something at T180 in the trop. So, this is right on the edge of possibilities and if the models are still showing it in a couple of days time we could be onto something .

Please forgive and correct me if I'm wrong

Edited January 22, 2016 by Bob G

[Chris K]

57 minutes ago, IDO said:

We are seeing a strong El Nino combined with a cold strat PV and AAM off the charts, a rare occurrence, so we are really in the dark as to how this will play out, so maybe assumptions about a cold Feb and March should not be banked, as to date nothing has really gone to expectations? Best just to follow the models and if they don't show cold, then maybe that is what happens when we get this type of background signals? 

If we are really in the dark as to how this will play out, maybe assumptions about a cold OR mild Feb / March should not be banked? I have seen plenty of times where the models are consistently showing mild and zonal right out to T+384 non stop, then a week later that has changed completely. Just like vice versa where a cold spell could be modeled to last for a couple of weeks then it gets shunted away in a few days...

Do the models tend to verify better when they show mild set ups in FI time-frames? People seem to assume that, based on the fact our weather is predominantly Atlantic sourced, but I genuinely do not know?

[cheeky_monkey]

4 minutes ago, Chris K said:

If we are really in the dark as to how this will play out, maybe assumptions about a cold OR mild Feb / March should not be banked? I have seen plenty of times where the models are consistently showing mild and zonal right out to T+384 non stop, then a week later that has changed completely. Just like vice versa where a cold spell could be modeled to last for a couple of weeks then it gets shunted away in a few days...

Do the models tend to verify better when they show mild set ups in FI time-frames? People seem to assume that, based on the fact our weather is predominantly Atlantic sourced, but I genuinely do not know?

if our weather is predominately atlantic sourced then you have answered your own questions...you dont need to be sherlock holmes to work out that if the models are showing mild weather in the outlook then 9/10 it will be right.

[Hotspur62]

Well looks like all the fun and games is  on the other side of the pond atm with the historic blizzard commencing and dumping  upto 3 feet of snow in the sweetspots. The models are all pretty dismal from a coldies  pov and the latest update from IF doesn't look too positive. However, things can change very quickly and whilst I accept we will not get another cold spell this month February still holds promise and with the help of the anticipated SSW (where statistically we have a 2 in 3 chance of cold coming to the UK if it does happen) I am still positive that February will trend colder as the month progresses.

I think that the blizzard in the US is acting as a "depressant" to some on here which is understandable but lets not focus on the US weather. Good Luck to them but lets not forget that the winter on the Eastern Side of the US has been pretty mild to this point. Lets get through  the next 7-10 days as painful as they might be and see what the models show us after that. I noted the comments of Tamara and CC of yesterday and concur with them that things will gradually look better as Feb progresses. If it doesn't happen then so be it but I think come this time next month we may be looking at things differently.    

[booferking]

Come on please show us something good on this 18z we really really deserve weather gods. 

[wishingforsnow]

Interesting post over on the TWO forums they claim that they have discussed with experts and the consensus is that the ECM is more likely the correct outlook rather than GFS

http://www.theweatheroutlook.com/twocommunity/default.aspx?g=posts&t=15798&p=49

Edited January 22, 2016 by wishingforsnow

[Chris K]

11 minutes ago, cheeky_monkey said:

if our weather is predominately atlantic sourced then you have answered your own questions...you dont need to be sherlock holmes to work out that if the models are showing mild weather in the outlook then 9/10 it will be right.

No you're right I don't need to be Sherlock Holmes, but I was interested in knowing if models handle westerly type weather patterns better than others. I missed the obvious, thank you.

I still stand by my point though - why should we bank Feb/Mar being cold or mild? We do not know even if one is more likely than the other.

Edited January 22, 2016 by Chris K

[Ali1977]

Call me ever the optomist, but I still think things could change early Feb - FI is not at 384 it's at about 216, obviously a lot going on stratospherically so I am sure the models are performing worse than normal - and let's face it, they aren't good beyond 240 at the best of times.

 

[northwestsnow]

18Z looks an improvement , its slower with the low at 144 off the eastern seaboard,and is quicker to clear the deep lows away from western greenland.

Edited January 22, 2016 by northwestsnow

[bluearmy]

Just an observation that we have now got an upcoming Alaskan ridge (was promised by some over a week or so ago). However, with the euro slug seeming to become a semi permanent feature for the next two weeks, we won't see anything particularly cold apart from some cold zonality behind CF's. 

we require the upstream amplification to draw the euro high west to become a mid Atlantic ridge. Suspect that remains the direction of travel though was hoping this westerly phase would be only a week rather than two. 

[Weather Observer]

The mothership has landed

[Ali1977]

Day 9 and main differences is that some WAA is building into Alaska , and a big lump of PV has moved over Scandy - still not looking great at this point as the Med and Rurope still has a giant HP

The ridgeing into Alaska could definitely help shift that PV away from Greenland though.

Edited January 22, 2016 by Ali1977

[Derbyshire Snow]

Hi all. This evenings model is once again showing the key drive being the strength  of the jetstream and  for many days yet it seems. There is a high probability of stormy winds throughout the UK at times next week. The strong polar vortex stretching down to mid latitudes unfortunately is in the wrong place. We need a SSW to split the PV or weaken it , but if that does not occur, then prolonged colder temperatures will be restricted to north east Europe. The polar vortex `should`  traditionally weaken in Spring but we require something to happen now.

The Azores high linking to a Bartlett is not helping matters one bit

Theres just a chance that the huge trough giving bad conditions in the US may disrupt  the jetstream and heights might develop in its wake as it moves out of US and in to the North Atlantic. Hopefully  it might but i am  not sure it will

 

Winter is far from done with yet and just maybe some surprises and the worst is still to come.

Latest image from my satellite system of The North Atlantic and the snowstorm in the US  downloaded 10.15pm

Edited January 22, 2016 by Derbyshire Snow

[winterof79]

59 minutes ago, wishingforsnow said:

Interesting post over on the TWO forums they claim that they have discussed with experts and the consensus is that the ECM is more likely the correct outlook rather than GFS

http://www.theweatheroutlook.com/twocommunity/default.aspx?g=posts&t=15798&p=49

I wonder if Singularity knows Storm Chaser?....Just a thought

[booferking]

Signs @240 18z that Greenland getting attacked with WAA from North and South.

[Derbyshire Snow]

Interesting middle and end of model run. The system leaving US is causing some interesting developments, heights trying to form over Greenland but i think jet stream too strong. mor e interested in the heights behind the big US trough

 

Jet stream wins out as usual , but on this run alone much better signs of cold in to February, Massive amount of cold to the North, we just need to tap in to it. The trough plunging in to Europe would be a great move as well

Edited January 22, 2016 by Derbyshire Snow

[Blake]

FI only... sorry... IF only...

 

I was scrolling through thinking it was early Feb and got a little excited. That depicts perfection for snow lovers. Uppers -8 to -12 UK wide too. One day we'll get our rewards. You know we could just all move abroad rather than moan!

[bryan629]

I would like to nominate the chart of the day to the GFS at +384 pfftt... 

Get out of that if you can MR.Nasty . >>>>>>> 

 

 

[wishingforsnow]

After these GFS runs we can only hope that the ECM is the form horse for the coming period end of January into February as it seems to be the lesser of 2 evils at the moment as we face another Atlantic dominated weather period for a while: bringing less volatile, mild conditions and with a quicker improvement towards building blocking at the end of the run. Especially beneficial towards North Western regions where the last thing anyone wants is to be plunged back into floods just when they are starting to put their homes and lives back together.

Although, it has to be said that strat warming is proving a remarkably consistent signal on the models and perhaps the ends of the runs are starting to show the beginning of the result of whatever could happen to the PV? Atlantic domination waning again mid February? Blocking? Still a lot to play for. 

Edited January 22, 2016 by wishingforsnow

[Singularity]

Perhaps GFS is just starting to get the hint... the 12z GEFS were exploring more in the way of theoretically correct paths than the previous few suites and now we have a det. run that's more amplified over the U.S. and almost gets there with the Atlantic.

I am so done with waiting for GFS to get with the times, so very much hoping tomorrow is the day!