Model output discussion - winter proper underway

[ArHu3]

9 minutes ago, Ali1977 said:

Greeny high tries to hold but looks like the PV's just to strong and is going to shut it down, however the trend of building a greeny high could strengthen , definitely one to watch.

I hope that this is something new the operational sniffed out this morning and the ensemble follows suit with more openings for a Greenland high

[Nick F]

Quite seismic differences between EC and GFS at only t+144: with EC making a lot more of the -EPO ridge across the arctic into Greenland by raising heights here.

EC seems to be the first model to perhaps start to truly grasp the effects of the highly anomalous -EPO ridge and wave breaking on the height fields over the arctic, but will it be sustainable height rises over Greenland? Perhaps we really can’t trust models past t+144. Interesting times ahead if this is a start of a new trend to see cross polar ridging effecting the height fields over Greenland, but not totally unexpected by some of us on here.

Edited December 20, 2017 by Nick F

[ArHu3]

3 minutes ago, Nick F said:

Quite seismic differences between EC and GFS at only t+144: with EC making a lot more of the -EPO ridge across the arctic into Greenland by raising heights here.

EC seems to be the first model to perhaps strait to truly grasp the effects of the highly anomalous -EPO ridge and wave breaking on the height fields over the arctic, but will it be sustainable height rises over Greenland? Perhaps we really can’t trust models past t+144. Interesting times ahead if this is a start of a new trend to see cross polar ridging effecting the height fields over Greenland, but not totally unexpected by some of us on here.

Also very different from ukmo, icon and gem are also making very small attempts at a Greenland high

[mountain shadow]

25 minutes ago, chris55 said:

ECM raising some eyebrows this morning, genuine Greenland high in the making. With the Alaskan ridge ridge migrating and splitting the PV!

I'm not sure I can recall a Greenland High courtesy of ridging from the Pacific rather than the Atlantic.

This must be a very rare synoptic  (if it occurs).

[knocker]

The ecm takes the wave a little further north (fine margins) at 12 Monday thus eliminating the Scotland snow risk. The second wave quickly forms and is over Ireland by 00 Tuesday with the associated front Scotland/Wales/Cornwall.

Over the next 24 hours it drifts north east to be near Ailsa Craig, and deepens quite considerable to be 964mb by 00 Wednesday. It then drifts slowly across the UK as it it fills before exiting into the North Sea.

So potentially a very unsettled two or three days with sporadic rain and the possibility of localized gales.

[Timmytour]

It's great to see Knocker back on the thread. While it's nice to see analysis of how what the models are showing might lead to a path of cold, it great to have an actual analysis of the weather we could expect from the runs as they are

[Seasonality]

20 minutes ago, Nick F said:

Quite seismic differences between EC and GFS at only t+144: with EC making a lot more of the -EPO ridge across the arctic into Greenland by raising heights here.

EC seems to be the first model to perhaps start to truly grasp the effects of the highly anomalous -EPO ridge and wave breaking on the height fields over the arctic, but will it be sustainable height rises over Greenland? Perhaps we really can’t trust models past t+144. Interesting times ahead if this is a start of a new trend to see cross polar ridging effecting the height fields over Greenland, but not totally unexpected by some of us on here.

I was thinking the same thing this morning. Has certainly been an interesting week of model watching. Quite fascinating differences at t+144 as you've pointed out

[Paul_1978]

1 hour ago, ArHu3 said:

It's very hard to edit a quoted post on a pc and on mobile nearly impossible ?

He surely just neede to rate the post as a Like or Thanks?!

Anyway, I'm sure we'll see our next named storm on the 27th!

[MR EXTREMES]

11 minutes ago, Seasonality said:

I was thinking the same thing this morning. Has certainly been an interesting week of model watching. Quite fascinating differences at t+144 as you've pointed out

Although the models don't look fantastic in the mid term, but suppose we need to see what's going to happen during this period of stormy weather coming.

Although from experience anything unsettled can lead on to wintry outbreaks.

The ECM has that ridge cutting in very fast.

[blizzard81]

Were people asleep all day yesterday? The ecm just carries on from yesterday's output with a very strong pacific ridge. Yesterday the gfs and ukmo were going down a similar path but have backed off this morning. 

[Duane S.]

Having viewed the 00z and speaking generally, I have to say I am becoming increasingly surprised that there aren't more eye candy charts on offer with the Pacific ridge and subsequent Arctic profile. 

[Borei]

GFS, in FI, is consistently showing high pressure building to our south and south east - a veritable winter killer. 

This is consistent with the MetO long ranger.

 

[Seasonality]

9 minutes ago, blizzard81 said:

Were people asleep all day yesterday? The ecm just carries on from yesterday's output with a very strong pacific ridge. Yesterday the gfs and ukmo were going down a similar path but have backed off this morning. 

Maybe everyone is busy with Xmas preparations? Anyway, far from clear what will happen by even t+144 this morning, so plenty of interest imo.

[Seasonality]

3 minutes ago, Borei said:

GFS, in FI, is consistently showing high pressure building to our south and south east - a veritable winter killer. 

This is consistent with the MetO long ranger.

 

Well, not really though. This is 240 to 384 on the latest GFS run, hardly a raging Bartlett high.

[ArHu3]

44 minutes ago, Paul_1978 said:

He surely just neede to rate the post as a Like or Thanks?!

Anyway, I'm sure we'll see our next named storm on the 27th!

Maybe in this case but sometimes you really just want to quote a small part of a large post but I have given up doing this on mobile 

[phil nw.]

Morning all,

A few earlier ot posts were removed. Just a reminder that the like system is usually sufficient to thank someone for their post, however the pm system is also there if further comments are needed. This saves clogging the thread up, especially if a long post is re-quoted. 

Thanks all, have a good day. 

[Nick F]

55 minutes ago, Seasonality said:

I was thinking the same thing this morning. Has certainly been an interesting week of model watching. Quite fascinating differences at t+144 as you've pointed out

Not a great fan of the meteociel 500mb/slp charts that a lot use and post on hereTBH, think it's the colour scales, but also the Mercator projection for Europe, prefer Netweather or wetterzentrale colour scale for 500mb and the projections. With regards to the  effects of the -EPO ridge on the arctic and Greenland height fields, loop of the EC 500mb timeframes can clearly be seen ion the loop below (need to click in to it):

Be interesting to see if subsequent GFS runs pick up on the Greenland height rises and if the 12z EC has more sustained +ve heights over Greenland, as past t+168 the +ve heights over the arctic relax their influence with low heights taking over to our north.

Think we really need to rely on the high res runs to lead the way on the effects of the -EPO ridge over the arctic as the ensembles may be missing the changes in the early stages of initialization of the runs. But even the high res runs are just starting to catch up on the effects of EPO / MJO.

Edited December 20, 2017 by Nick F

[Chesil View]

Certainly some intetesting developments regarding possible build of polar hieghts on the ECM this morning. I seem to recall GP suggesting that around the 21st/22nd December might be the period that the NWP models might start to show some interesting runs. Early days of course and would be interesting to get an update from GP on how he thinks things are progressing with regards to his suggestiobs if hieghts building to our northeast after xmas.

Edited December 20, 2017 by Broadmayne blizzard

[mb018538]

1 hour ago, Timmytour said:

It's great to see Knocker back on the thread. While it's nice to see analysis of how what the models are showing might lead to a path of cold, it great to have an actual analysis of the weather we could expect from the runs as they are

We all know the short to mid term outlook if knocker is posting regularly again  

I don’t think the models have this nailed down by any stretch yet. Really struggling to get to grips with the NH profile.

[ArHu3]

2 hours ago, ShortWaveHell said:

Was waiting for something like that at 240h , didn’t expect it at 120-144

In the past cold spells always appeared on relative short notice (+168h)but that was a long time ago, I would have guessed the models must improved by now 

[carinthian]

The much improved NAVGEM was the first model to pick up Polar Height Rises in its runs a few days ago. This mornings latest 300mb wind flow chart clearly shows a developing -AO  over the Arctic at 180t. On each run from the other main models the North Atlantic jet is now being pushed further south. Forecasting will not be easy with this developing situation but looks like the earlier forecasts for post Christmas Tm circulation,   especially from ECM into NW Europe being pushed further SE with each run.

C

[northwestsnow]

EC does offer some snow depths again- this time the north pennines is the big winner but alas, anything wintry looks very transient as that horrid piece of vortex over canada spills its energy across the Atlantic on a strong jet.

Earlier developments allow just about enough energy to go south enough to brings wintry weather between 192 and 216hrs- but by 240 it looks a lost cause as the azores high is already ridging into Spain/France.

The only hope is the high over NW Russia can push west to deflect the jet SE again but that looks a long shot -

Perhaps with a bit of luck we will see the high way to the NE gather strength (it will need it against an angry looking Atlantic. )

[Ali1977]

Right then GFS, let's get some energy into the pole as per the ECM.

[northwestsnow]

I'm no expert but there is a 10Hpa  warming over Siberia on GFS 0z getting started in around 3 days 

Which carries on until the end of the run- a few snapshots..

168

192

216

and by the end-

This is from the GFS model, and i have to confess, i'm not entirely sure what effect this will have down the line..

[Frosty.]

The thinking is, or certainly was that the northern arm of the jet will weaken considerably again as we go further into January following it's angry christmas / new year phase..?..really hope Jan / Feb deliver the kind of severe cold from the East we have been sadly lacking in the last few years..