Model Output Discussion - January 11th.

[snowmadchrisuk]

Thanks for the reply I'll be honest, this is probably the most unsure I've seen the models and this forum since I joined. Everything is so volatile, changing every single run to something different!

From what I can gather, the setup we're currently in is one that has many different doors leading out from it.. Hopefully we can get the right one!

PV moving west ... massive Scandi high , I still say look East for our first country wide Cold spell , and I dont really go along with the ECM later output , I dont think low pressure will be able to get that far east .. although it still shows a cold outcome I dont think its the right one

Edited January 12, 2012 by snowmadchrisuk

[IDO]

00z GFS kills any chance of an Easterly this side of Feb?

Again nothing develops, wintry wise, till the end of FI.

Atlantic/Jetstream dominant in reliable time frame after a cold few days over the weekend.

Models and runs becoming more consistent in their trend: the first chance of wintry weather will miss our shores.

Today should rubber stamp the above so yes the omens for Jan are trending poor for snow and we have to hope the couple of chances that may or may not occur in Feb will come to fruition. Tick tock...

[Paul]

00z GFS kills any chance of an Easterly this side of Feb?

Again nothing develops, wintry wise, till the end of FI.

Atlantic/Jetstream dominant in reliable time frame after a cold few days over the weekend.

Models and runs becoming more consistent in their trend: the first chance of wintry weather will miss our shores.

Today should rubber stamp the above so yes the omens for Jan are trending poor for snow and we have to hope the couple of chances that may or may not occur in Feb will come to fruition. Tick tock...

Hmm, you talk about FI as being unreliable (GFS incidentally shows a few cold shots from the end of next week - albeit not from the east) but then suggest today will rubberstamp the outcome until the end of the month? Not sure the two can possibly go hand in hand.

[winterof79]

Again the ECM has the atlantic meeting the block and starting sending the trough s/e in to europe http://www.meteociel...1-168.GIF?12-12 .Consistancy is the key.Docked.. http://www.meteociel.fr/modeles/ecmwf/runs/2012011200/ECH1-192.GIF .

Edited January 12, 2012 by winterof79

[IDO]

Hmm, you talk about FI as being unreliable (GFS incidentally shows a few cold shots from the end of next week - albeit not from the east) but then suggest today will rubberstamp the outcome until the end of the month? Not sure the two can possibly go hand in hand.

The Synoptics were as good as they have been all winter and if we did not get cold with this shot it would be back to the zonal train. Strat warming looks the only thing that will shift the pattern and it is now cooling so we have missed that first shot. Feb will reflect other warming events and will aid with dislodging the omnipotent jet stream , but this month now looks too late. Of course with zonal we may get some transitional cold but I think most members are looking for sustained cold.

Edited January 12, 2012 by i'm dreaming of...

[Jason T]

00z GFS kills any chance of an Easterly this side of Feb?

Again nothing develops, wintry wise, till the end of FI.

Atlantic/Jetstream dominant in reliable time frame after a cold few days over the weekend.

Models and runs becoming more consistent in their trend: the first chance of wintry weather will miss our shores.

Today should rubber stamp the above so yes the omens for Jan are trending poor for snow and we have to hope the couple of chances that may or may not occur in Feb will come to fruition. Tick tock...

Hmm, you talk about FI as being unreliable (GFS incidentally shows a few cold shots from the end of next week - albeit not from the east) but then suggest today will rubberstamp the outcome until the end of the month? Not sure the two can possibly go hand in hand.

Indeed Paul could not agree more. I think to call rubberstamp based on that ECM run and furthe runs today is just not plausable. i believe that the MENS are already in play in respect to different agreement's on each model and also the same but at seperate run time's. This is a BIG pattern change going on allround and time is not running out,Just the model's are juggling conclusion's. Prog date 15th.

SL

[winterof79]

UKMO to an extent and ECM both developing the low s/e of Greenland at 144z

http://www.wetterzentrale.de/pics/Rukm1441.gif

http://www.wetterzentrale.de/pics/Recm1441.gif

GFS pushes it n/e

http://www.wetterzentrale.de/pics/Rtavn1681.png

[Jason M]

quick post to summarise

GFS = Zonal (control is better)

ECM = Looks like yesterdays 12Z run on quick inspection (which is ok!)

GFS Ensembles = Still updating but the 'day after tommorow' runs look to have largely vanished. Some support for ECM outlook though within them

METO = As always the pot of gold is at day 10, so METO not that relevant IMO as not enough data (know some will disagree)

Cannon Fodder models = generally not great and tending to back GFS

I may have missed something as not much time

Worth mentioning that the AZores high is in control one way or another on nearly every model (not good!). Just because the PV moves and things change globally it doesnt mean the Azores high will clear off. IMO, unless it does were out of luck (except maybe a brief toppler).

Jason

[snow drift]

The Synoptics were as good as they have been all winter and if we did not get cold with this shot it would be back to the zonal train. Start warming looks the only thing that will shift the pattern and it is now cooling so we have missed that first shot. Feb will reflect other warming events and will aid with dislodging the omnipotent jet stream , but this month now looks too late. Of course with zonal we may get some transitional cold but I think most members are looking for sustained cold.

I am not sure that you can say from the recent output that we will be back in the Zonal train. With the jet trending to go further south and not as powerful as it was. In fi there is indications of blocks being set up and the PV is being shown to move. Time will tell but to suggest that with 19 days left of the month, it will not change, is not appropriate IMO.

[Paul]

The synoptics haven't been good for cold at all yet, some FI charts have shown decent chances for cold later in the month, but none have actually occurred yet, so not sure what chance has been missed?

As for the stratosphere - the initial warming starting to work it's way down, with more warmings forecast in the not too distant future by both the GFS and ECM. There is always a timelag on changes in the stratosphere.

In terms of the Change to zonal conditions you were keen to point out that any cold was in FI - well any change to screaming zonality is as well. But back to the original point - you can't have your cake and eat it, if you want to say FI is unreliable then you really can't create a forecast based on it for the next 18 days or so.

[bluearmy]

Not allowed one liners but ecm is the model to follow on this. It maybe a little progressive but it's setting the agenda.

[Roger J Smith]

Flow is buckling and becoming more volatile all around the hemisphere now, looks good in general and we could hope that the ECM is generally on track, although a more robust cold advection towards the end would be plausible if that's the trend (widespread pressure rises across northern Europe but not much land mass under -10 C at 850 mb, seems like it could be upgraded),

Another possible outcome that is hidden in the perturbations would be that this current minor blocking episode would build more dramatically and transform into the high latitude blocking without the return to the Atlantic. That's probably a longshot but we should be watching for a more limited return to mild mid-week than the GFS was advertising.

[VillagePlank]

GEFS Analysis, London, Thurs 12th, 00z output,

Edited January 12, 2012 by Boar Wrinklestorm

[Radiating Dendrite]

People getting too hung up on the easterly.

The big change is happening and the ecm is leading the way. As Ian says and indeed GP, look north not east.

[VillagePlank]

I'm considering adding weighting to my GEFS analysis. Here's the same one as a couple of posts above, but with the dotted lines showing how far to either the minimum or the maximum the overall ensemble spread is,

Shows, unfortunately, that that cold member seems to be way out on it's own ... yes, at period 33 (19th Jan) we are much more likely to see one of the ensemble members posting warmer than the mean 850hPa than those posting cooler.

As for predictive power - who knows?

Edited January 12, 2012 by Boar Wrinklestorm

[shedhead]

All the overnight outputs have drifted towards the evolution suggested in the UKMO 6-15 dayer from yesterday, with the Atlantic set to win the battle again as we go through next week. Despite what currently looks like solid agreement on this though I still think there is time for a complete volte face from the models IF this weekends HP ultimately builds in a more favourable position - the next 24hrs should see this resolved one way or the other.

[mountain shadow]

All the overnight outputs have drifted towards the evolution suggested in the UKMO 6-15 dayer from yesterday, with the Atlantic set to win the battle again as we go through next week. Despite what currently looks like solid agreement on this though I still think there is time for a complete volte face from the models IF this weekends HP ultimately builds in a more favourable position - the next 24hrs should see this resolved one way or the other.

Erm no. The ECM is showing great consistency in moving the PV away westwards from Greenland (see my post from last night), it has moved from T+240 to T+168.

[bluearmy]

All the overnight outputs have drifted towards the evolution suggested in the UKMO 6-15 dayer from yesterday, with the Atlantic set to win the battle again as we go through next week. Despite what currently looks like solid agreement on this though I still think there is time for a complete volte face from the models IF this weekends HP ultimately builds in a more favourable position - the next 24hrs should see this resolved one way or the other.

forget next week. there is no easterly next week as modelled over the weekend and into monday. the change comes as the trough drops into europe, aided by the blocking to out ne. you have the chance of an easterly once the trough has dropped in. thats next weekend onwards.

[Cecil Hogmanay Melchett]

I can't post charts because of this damn unbuntu system but i think the overnight runs continue to diverge from each other.GFS looks out of line compared to the UKMO/ECM which both make more of the buliding high across NW Russia.

The main difference between ecm and gfs is the Atlantic profile with ecm bulding heights from the azores into the Atlantic and finally into GReenland.

I hope ECM Is correct here because gfs is another frustrating run athough the ecm evolution looks risky.

UKMO only goes to 144h but it defo looks more like ecm to my eyes.

summary,i really dont think we are closer to knowing what the last week of jan will bring this morning.

[Isolated Frost]

That upper trough digging into europe in the next few days is a trigger, and I believe the time is closing in on the first real cold spell of the winter for many southern areas. The road is still paved for north-west to north winds as that trough digs down into europe, with the jet axis orientated nw-se, and that vortex slipping away to baffin/nunavut.

Stratospherical warmings will indeed have some impact on the hemispherical pattern and so I believe the aleutian ridge will eventually link with the siberian high, this to further quash the PV.. The motion for high-lat blocking as we move into feb.

Apart from the warming forecast by the ECM, another substantial warming, this time closer to the pole, would finish it off in my opinion.. The vortex is building back or at least the flow is still uncertain for arctic blocking unless we get another strat warming.

A cold front with some gusts, especially in the NE today, followed by a good few days dominated by clear skies and at times, cool temperatures.

[lorenzo]

Looking North good height rises on ECM 240 chart. A visit from a lobe of PV for the final third of the month.

Not the fabled Easterly, and not the pseudo Bartlett ridge either. Another solution on the table. - 10 uppers across the UK.

Hard to see things not looking like a proper winter blast from here.

[Paul]

New thread - The models: Summed up.

Perhaps now is a good time to post a morning update? Be great to see as many people as possible getting involved in what could be a fun and interesting thread to follow:

http://forum.netweat...dels-summed-up/

[nick sussex]

Still disagreements this morning between the ECM and GFS, although at least they both agree on the main PV edging further west before the GFS brings it back in its lower resolution output.

The ECM of course looks the best today from a cold perspective but with one caveat, I don't like its hint of a western based negative NAO, this may not be an issue if that troughing can get pushed all the way into mainland Europe but preferably you want the low centred to the east so that if it remains slow moving you're on the cold side of the troughing.

Looking at its ensemble mean that looks okay with PV north of Hudson Bay and troughing over the UK with strong ridge to the east and ne:

http://www.meteociel.fr/modeles/ecmwf.php?ech=240&mode=1&map=1&type=1

In the earlier timeframe the models have taken that ridge further north, and it certainly looks frosty for several days before this sinks, as soon as that high becomes separated from the ridge to the east you want it to go quickly to allow troughing to dig se.

If you look at the ECM ensemble maps you can see why its important you get rid of that high quickly once its decided to sink

http://www.ecmwf.int/samples/d/inspect/catalog/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!168!pop!od!enfo!enplot!2009112700!!/

The best looking ensembles at 168hrs carve more se tilt to the jet with the ridge displaced to the west this is as a result of more amplification upstream, this now is the next thing to look for, the more amplified this is the more digging into Europe you'll get with the troughing as this will be forced between a mid latitude high to the west and the high to the east and ne.

[Osbourne One-Nil]

Can I just ask, and this is for the benefit of members who are still learning....not myself; lots of talk of the polar vortex and what it might do. What do we want it to do if we want to se an increased risk of cold?

[nick sussex]

I think GP will be delighted with the ECM particularly with regard to his forecast.

Its all a fair way off though and I wouldn't be worrying about a possible West based -NAO, I'd worry about getting the -NAO in the first place.

Of course, we haven't even got to that point yet and the ECM is still very good but whilst these differences remain between the ECM and GFS then its hard to have too much confidence in the outlook.