Model Output Discussion - 1st February Onwards 12z--->

[johnholmes]

Just scanning through the ens. outputs this morning and the Atlantic pattern does look well set out to week 2 of the runs.

The naefs and ecm ht anomalies at day 10 

naefsnh-0-0-240.pngEDH101-240.gif

 

however just a hint that the jet turns more nw-se in towards month end so a chance perhaps of something colder if this develops.

naefsnh-0-0-384.png

 

the overall pattern looks similar but if the Azores high retreats a little then a colder Northerly shot rather than the brief north westerlies we will see in the next few days could be quite possible.

 

In the meantime over the next 10 days or so it all looks very average some cooler and some milder days between the frontal systems with the drier conditions further south and east.

 

The ECMWF-GFS anomaly charts have, this morning, shown something along those lines. Be careful with these though it is the first fairly close similarity between these two in several days. NOAA 6-10 has yet to follow this idea. 'This idea'=a slight veering of the upper flow to bring the flow into the UK from just N of W but still with fairly high contour values. It needs some cooling in those heights and more veering on all 3 before it can be said to be a done deal. However, it was the EC-GFS combination that led NOAA to the prediction of the coldish spell post Christmas Day so coldies keep your fingers crossed for a day or two yet.

[IDO]

As far as the bigger picture is concerned we are likely to see a slow breakdown of the stubborn high pressure across much of Europe - a real winter killer for the UK as far as snow chances go as it is too low latitude to give anything from the East and too stubborn to allow anything to dig down from the North.

 

This will take some time with the South having the best of the dry weather while unsettled weather tries to push in from the NW at times.

It could feel quite pleasant at times in the South next week as temps lift somewhat.

 

We are still on course for a slow pattern change into the last week of February with our old friend the Euro trough setting up. The signal for a return to cooler/colder zonal conditions to return is gathering pace a little now but hard to know how cold or prolonged it may be.

There is no sing of a true blocked cold spell setting up as yet and we will have to wait another week or so to know if that is a possibility as any potential blocking would be well outside the 10 day range.

For now it is case of seeing if this signal for the Euro trough can strengthen further and trying to nail down how far West/East it is likely to set up and how amplified the pattern behind will be.

 

Yes the 10-15 day ECM ensemble mean clearly supports the GEFS that has been consistent for days:  

 

  WSI_Energy

Shades of February 2014. 500mb 11-15 day period forecast from ECMWF looks spot on with last year's February pattern. http://t.co/ejKvI9QKTw

13/02/2015 14:55

 

Very little chance of Northern blocking before March.

[Paul]

As far as the bigger picture is concerned we are likely to see a slow breakdown of the stubborn high pressure across much of Europe - a real winter killer for the UK as far as snow chances go as it is too low latitude to give anything from the East and too stubborn to allow anything to dig down from the North.

 

This will take some time with the South having the best of the dry weather while unsettled weather tries to push in from the NW at times.

It could feel quite pleasant at times in the South next week as temps lift somewhat.

 

We are still on course for a slow pattern change into the last week of February with our old friend the Euro trough setting up. The signal for a return to cooler/colder zonal conditions to return is gathering pace a little now but hard to know how cold or prolonged it may be.

There is no sing of a true blocked cold spell setting up as yet and we will have to wait another week or so to know if that is a possibility as any potential blocking would be well outside the 10 day range.

For now it is case of seeing if this signal for the Euro trough can strengthen further and trying to nail down how far West/East it is likely to set up and how amplified the pattern behind will be.

 

This morning's ensembles picked this up really well. 

 

  

[johnholmes]

This morning's ensembles picked this up really well. 

 

ens1.png ens2.png ens3.png

 

Yes that pattern, if perhaps not the actual anomalies shows nice and simply the idea that is gaining ground within most of the model outputs.

 

So in terms of northern blocking=no, but something not that different to what the UK area has seen at least twice this winter, a veering of the upper flow as the Atlantic upper ridge and Scandinavian (area) upper low inter react to give a colder flow. How long, who knows this far out. IF the 8-14 NOAA starts showing this consistently then that will give a good idea. If only the 6-10 starts (it is not yet showing this-only the EC-GFS output at the moment) then 6-10 days possibly a bit longer. If that comes away from the idea after only a couple of days then no more than 3-4 days.

Edited February 13, 2015 by johnholmes

[knocker]

Having a quick look at the 00z ext EPS mean it has the LP further west Greenland way and the HP a tad flatter and further south so the flow more W than NW. Await to see how this evenings evolves.

[IDO]

I ignored the FI on the 0z GFS suite as it appeared to be a departure from the mean runs of late and the 12z has now reinforced that with lots of scatter again after D8/9:

 

 

However the op and control continue with a UK HP in charge from D4 to D11:

 

 

 

A relatively dry run for Birmingham south. GEM has also ditched it's more unsettled 0z run and follows the GFS op with a settled period from D4. By around D9 it is a N/S split but much better than this morning's run. Even UKMO are now suggesting a longer spell of HP with most of the UK benefitting and has moved towards GFS:

 

 Compared 0z: 

 

There was a suggestion yesterday that the high was sinking in the short term, but the GFS op, control and Mean remain solid for a robust UK wide High from D4 till at least D9 with only a brief wet spell for the NW as the highs merge around D6:

 

GFS D8 mean and control:  

 

The D11 GEFS are not really giving any direction of travel: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=264

 

A couple of interesting members with half decent NH profiles:

 

 

 

But not really anything that suggests a change is on its way.

 

 

 

 

 

 

 

[bluearmy]

Having a quick look at the 00z ext EPS mean it has the LP further west Greenland way and the HP a tad flatter and further south so the flow more W than NW. Await to see how this evenings evolves.

 

true knocks but as i alluded this morning, the mean anomolys will take account of all the runs, inc those which are wrong. the trend on the spreads by day 10 is to sink the lower heights further south and west than the mean and anomolies. if that continues, you can expect the whole pattern to correct in that direction as time ticks by. 

[johnholmes]

true knocks but as i alluded this morning, the mean anomolys will take account of all the runs, inc those which are wrong. the trend on the spreads by day 10 is to sink the lower heights further south and west than the mean and anomolies. if that continues, you can expect the whole pattern to correct in that direction as time ticks by. 

 

that little word again (IF)!

[J10]

The latest Ski blog now up

 

https://forum.netwea...-february-2015/

 

Please give it a read, as viewers numbers have been dropping.

 

Very much a split this week

 

Mild, dry and sunny for the North East with perhaps the chance of a foehn wind at times. No bad skiing conditions, especially for the morning.

 

More unsettled to the South and West, with the risk of heavy precipitation for NW Italy Sunday into Monday, temps are no perfect, so by no means an entirely snow event, but on higher slopes, quite a lot of snow is possible, with perhaps over a 1m in places.

 

From midweek onwards looking dry everywhere for the Alps.

[Ali1977]

The Alps are in for a hammering, 12 feet in next 6 days.

[ANYWEATHER]

Looks as though we are in for mainly milder weather ,with occasional blips of colder weather especially for the North, regarding the gfs and ecm. The gfs at the end of the run brings us into March with unsettled conditions from the Atlantic.

[Daniel*]

Seen much worse ensembles does keep options open.

Agreement on a short cold snap on Tuesday with the chance of snow, low lying ares might scrape a wet snow shower sums up the winter, as we draw into 3rd week there's legroom in the colder options with a general slope down however big scatter - looking average to below as a safe bet IMO. Bar few mild days february is not looking tropical. I'm sure a last hurrah would be a nice tonic, for many dazed winter folks.

[ANYWEATHER]

Seen much worse ensembles does keep options open.

Agreement on a short cold snap on Tuesday with the chance of snow, low lying ares might scrape a wet snow shower sums up the winter, as we draw into 3rd week there's legroom in the colder options with a general slope down however big scatter - looking average to below as a safe bet IMO. Bar few mild days february is not looking tropical. I'm sure a last hurrah would be a nice tonic, for many dazed winter folks.

image.jpg

Hi .Little chance Buddy on anything wintry with these charts away from the Scottish mountains....

[bluearmy]

ECM ens mean and, more importantly, spreads continue to advertise any high SLP period being reduced ed to a few days. The pattern sinking south on a west/east basis. Nothing particularly cold within ten days unless the systems suddenly dive se in the next few runs. could be some pretty windy conditions as lows pass across the uk. Doesn't look like the blocky gfs, that's for sure.

EDIT: extended eps back the euro trough and low anomoly west a few hundred miles. That brings us into the game on the western side. could easily end up in a similar place to the last trough although I suspect this time, with less strat support, it will be les sustained.

Edited February 13, 2015 by bluearmy

[knocker]

ECM ens mean and, more importantly, spreads continue to advertise any high SLP period being reduced ed to a few days. The pattern sinking south on a west/east basis. Nothing particularly cold within ten days unless the systems suddenly dive se in the next few runs. could be some pretty windy conditions as lows pass across the uk. Doesn't look like the blocky gfs, that's for sure.

EDIT: extended eps back the euro trough and low anomoly west a few hundred miles. That brings us into the game on the western side. could easily end up in a similar place to the last trough although I suspect this time, with less strat support, it will be les sustained.

 

I understand what you are saying ba but by T360 on ext eps hasn't the euro part of the trough weakened with the low heights over Greenland being more influential thus giving this N/S split in the Atlantic and the UK with a westerly airstream. NOAA 8-14 doesn't make as much of the Greenland low and pushes the HP further north thus tending to more NWN airstream,

Edited February 13, 2015 by knocker

[polar vortex]

Still confident of a pattern change last third of the month with much more in the way of northern 

blocking as we go into March. This due to tropical convection and MJO signal although the models

are struggling with this. The strat has ruled the roost this winter with very little in the way of 

northern blocking ( possibly due to very strong - QBO ) but hopefully we will see a change over the 

coming days and weeks.

[bluearmy]

I understand what you are saying ba but by T360 on ext eps hasn't the euro part of the trough weakened with the low heights over Greenland being more influential thus giving this N/S split in the Atlantic and the UK with a westerly airstream. NOAA 8-14 doesn't make as much of the Greenland low and pushes the HP further north thus tending to more NWN airstream,

I was commenting exclusively on the ECM extended. The NOAA chart (mean from T192 to T336 so it will have to include the period where there is no low euro anomoly). Will also have some gefs and gem ens input. If also has no 12z ECM input. Expect it to change over the next few days knocker if the ECM trend continues. (Yes john , there's that word again!)

it's the trend knocker and at the moment, it's headed into a repeat of what we've seen several times already this season. with it being in the 10day + timeframe, there is plenty of detail to firm up on.

[Frosty.]

Ecm 12z ensemble mean is still pointing towards an increasing bias in favour of colder westerly / northwesterly winds during late February. I know some will pour scorn on me for being positive about this as some already have today but let me just say, we cannot change the cards we are dealt, nobody on here desires a bitter easterly or northerly more than me and it hurts that this winter has been another flop for many low lying southern parts of the UK but what can we do..moaning about our bad luck won't change a thing but hopefully March will bring some cold and snowy weather.

[johnholmes]

I understand what you are saying ba but by T360 on ext eps hasn't the euro part of the trough weakened with the low heights over Greenland being more influential thus giving this N/S split in the Atlantic and the UK with a westerly airstream. NOAA 8-14 doesn't make as much of the Greenland low and pushes the HP further north thus tending to more NWN airstream,

 

Each to their own but I am happy to use the NOAA and EC-GFS WHERE they agree. I have almost lost count of the number of times they give the best guidance in the time frames available Be that a continuation of the then current upper pattern or a change either marked or not so marked. Two instances this winter and both reliably indicated by NOAA, indeed one of them first indicated by the EC-GFS combo which is something not often seen by me in the 5-6 years I have daily collected their data. And I hasten to add never used without my usual caveats and looking at whatever else is available to us.

[knocker]

I was commenting exclusively on the ECM extended. The NOAA chart (mean from T192 to T336 so it will have to include the period where there is no low euro anomoly). Will also have some gefs and gem ens input. If also has no 12z ECM input. Expect it to change over the next few days knocker if the ECM trend continues. (Yes john , there's that word again!)

it's the trend knocker and at the moment, it's headed into a repeat of what we've seen several times already this season. with it being in the 10day + timeframe, there is plenty of detail to firm up on

 

I was commenting solely on the ext eps, forget the NOAA for the moment, and my comment still stands. The euro anomaly is very weak by T360 and the Greenland low is the dominant factor. I'm not sure we are not at cross purposes here. I'm suggesting the trend is towards the analysis that has been around before with LP Greenland and HP to the SW of the UK.

Edited February 13, 2015 by knocker

[knocker]

Each to their own but I am happy to use the NOAA and EC-GFS WHERE they agree. I have almost lost count of the number of times they give the best guidance in the time frames available Be that a continuation of the then current upper pattern or a change either marked or not so marked. Two instances this winter and both reliably indicated by NOAA, indeed one of them first indicated by the EC-GFS combo which is something not often seen by me in the 5-6 years I have daily collected their data. And I hasten to add never used without my usual caveats and looking at whatever else is available to us.

 

I have no problem whatsoever with that.

[bluearmy]

. The euro anomaly is very weak by T360 and the Greenland low is the dominant factor. .

At that range, I'm not surprised!

If the euro low anomoly continues to be shown by the model, I suspect it will become more marked and be centred to our se (Switzerland /Austria/ Czech Republic). Again, no evidence it would be a sustained feature - yet.

[knocker]

At that range, I'm not surprised!

If the euro low anomoly continues to be shown by the model, I suspect it will become more marked and be centred to our se (Switzerland /Austria/ Czech Republic). Again, no evidence it would be a sustained feature - yet.

 

Neither am I but I'm afraid the reasons for your suspicions vis a vis the strengthening of the low anomaly to the SE are alluding me at the moment. Anyway we shall in the fullness of time.

 

EDIT

If it's of any interest I've just posted Michael Ventrice's updated analysis of events in the eastern Pacific in the North American thread.

Edited February 13, 2015 by knocker

[Nouska]

For those who don't have access to the ECM data on Weatherbell - the WSI blog has posted up some charts from the most recent ECM32. Headline - cooler into March.

 

 

 

Images courtesy of WSI  ...  http://www.wsi.com/blog/wp-content/uploads/ECM_125.png

[bluearmy]

The gem ens anomoly is broadly in line with the ECM knocker. Maybe two out of three models showing this anomoly pattern is where I'm coming from knocker ??