General Model Output Discussion:

[Methuselah]

Please continue:

Previous:

[Polar Continental]

Cold outputs from the models this morning, showing northern blocking becoming extensive at T228

All major models now on to continued mostly cold or very cold theme for the foreseeable future.

The GFS UKMO and ECM showing polar air rushing in on Thursday and Friday, with disturbances on all running in the flow on Friday, giving a chance of snow for some, but this will be marginal and light I think over most inland low lying areas of England.

The ECM shows another minor disturbance running down the flow on Saturday!

Looking further out, another interesting disturbance at T150, though this will be very marginal for most as a good deal of less cold air is shown to be getting in to the mix by then.

After that a ridge builds over the country around T150, then the GFS and ECM go big time for the easterly, with the GFS getting this going at T228.

Very interesting models this morning.

[Steve Edgefield]

Very interesting charts this morning, esp with reference to a potential easterly setting up. Would be interested to hear GP's thoughts on this - he posted an update in the In Depth section yesterday evening suggesting that the likely scenario is for the UK to be kept in a NW flow with the mean ridge being held out to our west - not mild but there was no mention of a possible pressure rise to the NE.

[Glacier Point]

Just a quick steer on the NWP operationals this morning...

Although all seem to be heading towards a sustained easterly, the tropical signals are very clear about the core of any mean ridge being centred to the west or north-west of the UK, potentially retrogressing in the very extended timeframe (t360+). The GFS ensemble mean supports this - still cold but masked if you look at the 850 hPa values.

Easterlies modelled this winter have tended to signal a quick evolution to a push of cold air from the NE. That said, it's not difficult to see why models are suggesting heights building over Scandinavia given a deep cold pool centred over the Canadian Arctic.

Edited January 26, 2010 by Glacier Point

[Terminal Moraine]

Agree with that, Paul. It's the second time within 24 hours that the GFS has shown strong pressure rises to the north and north east of Britain following the forthcoming northerly and there is now support from ECM. Interestingly the control run on the 00z is even colder than the operational and still has some support from other members although, as might be expected at that range, there is a fair degree of scatter.

It's still a long way off but definitely encouraging signs.

[SteveB]

Hi GP,

Are you not buying the easterly shown on the models, & favouring a more north westerly set up?

[Lewis]

Morning,

I'm glad i woke up early this morning to see the 00z .

Lovely models, modeling at it's best! I love the way the first northerly topples within a few hours bringing in a more "Northerly" feed instead of a NNW. Not only this, there's the chance of some transitional snow especially for E/SE, NE areas.

The colder air establishes and does not want to leave the East, with any approaching fronts not getting that far east with the precipitation ahead of the warm front's. Not as "generally cold regarding 850's, although there's not much difference compared to the uppers with previous runs yesterday".

I have noticed the sudden blocking coming into play later into FI, we don't have the best of blocking this second, but we are still getting our weather from the North, and hopefully in a week or two's time from the East

I'm just going to sit back and "hopefully" continue to enjoy these outputs over the coming days. I think a fair number of us will be surprised with the amount of precipitation they will be come Friday onwards.

I can't wait to test out my new weather station, it's due in the post today, as my other one broke i decided to spend £200 on the new orgein, but guess what.. I woke up this morning and now the other one seems to work fine now!! O'well, at least now i can compare.

Anyhow, enough of my gob this early in the morning, enjoy the models.

Roll on the 06z

Edited January 26, 2010 by Storm Force Lewis

[Polar Continental]

Agree with that, Paul. It's the second time within 24 hours that the GFS has shown strong pressure rises to the north and north east of Britain following the forthcoming northerly and there is now support from ECM. Interestingly the control run on the 00z is even colder than the operational and still has some support from other members although, as might be expected at that range, there is a fair degree of scatter.

It's still a long way off but definitely encouraging signs.

Morning TM,

Yes, I was hoping the GFS would repeat the northern blocking theme from this time yesterday, and with the ECM steering towards the same, I have a little more confidence this could happen now.

Still a long way to go though and with GP seeming a little tentative this morning I wont throw caution to the wind just yet.

Encouraging though as you say.

Edited January 26, 2010 by Polar Continental

[Frosty.]

Stunning 00z output for coldies, the Northerly looks potent and prolonged, possibly 4 or 5 days, especially further north east, into next week and a chance that it will remain cold but details sketchy at this stage, another peachy gfs 00z run which even improves on yesterday but was followed by a less than impressive 6z run so i'm expecting a less cold FI on the next run.

Edited January 26, 2010 by Frosty039

[Nick F]

Nice agreement from the 8-10 day mean H500 comparisons between ECM and GFS for the Atlantic ridge to build NE across the UK in the medium range and join up with the Siberian ridge.

... this will be reliant though on amplification of the trough upstream off NE N America/NW Atlantic. Though good agreement from GEFS members for this amplification of the trough, though less agreement on what happens to the east.

Before then, interesting low progged moving SE across Ireland, Wales and western half of England on Friday; snow on on its eastern/northern flank as cold air undercuts from the north, rain would be likely across Wales and SW England though. Track of the low still will be uncertain this far out, so the snow margin may to and fro a bit over next few days:

http://cache.netweather.tv/fax/PPVK89.png

After the low moves though though, coastal areas even in the west in with a shout of seeing some snow showers, though the 'wishbone effect' common during showery N'erly flows with no fronts/troughs probably meaning it'll be dry inland.

[Snowyowl9]

Morning,

I'm glad i woke up early this morning to see the 00z .

Lovely models, modeling at it's best! I love the way the first northerly topples within a few hours bringing in a more "Northerly" feed instead of a NNW. Not only this, there's the chance of some transitional snow especially for E/SE, NE areas.

Roll on the 06z

I would say theres a more NW-ly flow on todays runs,besides saturday when theres a straight N-ly.

http://weather.unisys.com/gfsx/9panel/gfsx_850_9panel_eur.html

As you can see on there no mild at all,theres still another high coming in again to the west,

and of course GFS and ECM showing a mighty cold easterly in FI.

[Lewis]

I would say theres a more NW-ly flow on todays runs,besides saturday when theres a straight N-ly.

http://weather.unisys.com/gfsx/9panel/gfsx_850_9panel_eur.html

As you can see on there no mild at all,theres still another high coming in again to the west,

and of course GFS and ECM showing a mighty cold easterly in FI.

Yep,

That's what i was looking at "Saturday" is looking very interesting indeed. And that beasterly, yes please

[BLAST FROM THE PAST]

Hi GP,

Are you not buying the easterly shown on the models, & favouring a more north westerly set up?

Steve

I believe GP is suggesting that pressure should be high to our W or NW. This would provide a more general N and sometimes NE'ly flow. The case of a very deep cold pool over Canada suggests that Scandi HP is feasible. I do believe an easterly is likely in Feb and I mentioned yesterday on my outlook to bin any model showing a breakdown and westerly set up from t168 on aas models will soon pick up on the evolution. I didn't expect it to happen so soon and I didn't expect an easterly so early as ECM shows. BUT OVERALL the models look like the signal is picked up now....and round 3 of cold winter beckons.

BFTP

[The PIT]

Deep FI loosing it's marbles. If it comes off we're going to be looking at one of the coldest winters for a very long time. The only oil in the ointment is that secondary feature bringing in a warmer sector this week.

[Lewis]

Deep FI loosing it's marbles. If it comes off we're going to be looking at one of the coldest winters for a very long time. The only oil in the ointment is that secondary feature bringing in a warmer sector this week.

Hi mate,

Over the past 3 days it has at worst shown the warm sector covering western isles, with eastern areas not marginal and perfect, recent runs have shifted the warmer sector further west, and it also appears to just evaperate. So for your area you have a lot of "room" for margin. Which i suppose is better than a straight "It's way to marginal".

[Glacier Point]

Nice agreement from the 8-10 day mean H500 comparisons between ECM and GFS for the Atlantic ridge to build NE across the UK in the medium range and join up with the Siberian ridge.

You can add the GEM ensemble mean days 11 through 15 to that as well Nick....

http://raleighwx.easternuswx.com/models/cmcensemble/00zCMCENS11-15day500mbHeightAnomalyNH.gif

Striking how the polar vortex is once again being modelled scattered to the for winds with a series of cut off lows spinning around a building Arctic ridge. I'm thinking the upper weakness around the Azores will be our main driver, helping to suppport a mid Atlantic ridge (favouring a north or NW'ly flow) although the Siberian High looks once again to power up.

If we are to see a gradual weakening in the polar westerlies and substitition with easterlies, the expansion of the Arctic High is firmly on the agenda. Those polar westerlies are the only thing keeping us from hitting the jackpot for the third or fourth time this winter.

[derrylynne]

Deep FI loosing it's marbles. If it comes off we're going to be looking at one of the coldest winters for a very long time. The only oil in the ointment is that secondary feature bringing in a warmer sector this week.

Looking at this morning charts I am surprised there is not much excitement in F1 with a raging beast from the East. The GFS could be picking up on something. Particular as solar events are pointing to a very cold February. Will be interesting to see what the next set of charts bring and if they all fall in line....

[Tim Bland]

Latest Faxes -

http://www.meteociel.fr/modeles/ukmo2.php?ech=72&carte=2000

http://www.meteociel.fr/modeles/ukmo2.php?ech=84&carte=2000

I like the Friday 00 chart, it shows 3 bads of precipitation. A good chance of many Central and Eastern areas having a covering on Friday.

Based on these I would expect forecasts to start talking up the snow risk for friday and even start issuing warnings.

Beyond, if you look at the ensembles they have been showing an easterly fron the 5th for days now. People only look at the operational but its been on its own for a while.

Edited January 26, 2010 by Tim Bland

[TEITS]

Can't say im surprised by the E,ly being shown on the models. Very pleasing from a forecasting perspective as at the moment it looks as though I even got the date right (4th Feb).

Obviously its early to start ramping but as the GFS/ECM/GEM all go for an E,ly these are promising signs. Rather simply put if some of the charts this morning come off then the 09/10 winter will be remembered for many years!

[cooling climate]

Looking at this morning charts I am surprised there is not much excitement in F1 with a raging beast from the East. The GFS could be picking up on something. Particular as solar events are pointing to a very cold February. Will be interesting to see what the next set of charts bring and if they all fall in line....

I think this post qualifies as excited.

The 0z GFS run is a ABSOLUTE STONKER of a run probably the best I have ever seen but

even this run could be surpassed over the coming days who knows.

From Scotland down the eastern half of the UK into East Anglia and parts of the southeast

from this Friday the temperature does not rise above 2c for the entire run.

Even though the northerly topples the east stays very cold.

T216 and its easterlies all the way. The control run in the ensembles gives its full support

to magnificent run which brings ice days, snow, frost, wind chill, its got the lot.

excellent, excellent run.

A good sign of how cold this winter has been is when forcasters are calling today's maximum

temperatures of 2or 3c as chilly. In our past mild winters this would be classed as a freeze

(I'm not joking either). Maybe they are saving the more headline grabbing expletives for next

week and onwards.

Edited January 26, 2010 by cooling climate

[Nick F]

You can add the GEM ensemble mean days 11 through 15 to that as well Nick....

http://raleighwx.easternuswx.com/models/cmcensemble/00zCMCENS11-15day500mbHeightAnomalyNH.gif

Striking how the polar vortex is once again being modelled scattered to the for winds with a series of cut off lows spinning around a building Arctic ridge. I'm thinking the upper weakness around the Azores will be our main driver, helping to suppport a mid Atlantic ridge (favouring a north or NW'ly flow) although the Siberian High looks once again to power up.

I noticed in your earlier post and your analysis in the techy thread that with the tropical signal you are favouring the mean ridge to position just to our NW/W? I presume this may mean that the mid Atlantic ridge building NE, as the trough upstream amplifies, does not link up with the Siberian/arctic ridge but instead we keep a mean trough to the east? This would still mean a cold flow from the N or NW. Does this still look more likely than easterlies with a ridge buidling to the N and NE?

Be interesting to see which way we go, but nothing pointing to the flow coming from a mild direction as we go into early Feb.

[Glacier Point]

Indeed Nick, below average looks prolonged.

There seems to be a trend for the ridge to shift around edging first eastwards and northwards due to he residual cold pool over the Canadian Arctic edging around and dropping cold uppers into the upstream flow. As this part of the PV weakens and begins to lift out, we should see the ridge being pulled back west and north. But that's probably taking the modelling too literally and I would prefer to favour Global Wind Oscillation composites for phase 5 perhaps 5-6-7 type orbit which suggest the strongest positive H5 anomaly to our west / NW.

[Lewis]

Everything seems further East on this run, with the sinker not amounting to much, its the secondary behind that im more concerned about.

Lovely mild sector from the LOW to the west now bang smack over all of England and Wales. No handbags out yet... But friday is a non-event on this run.

Edited January 26, 2010 by Storm Force Lewis

[cowdog]

Everything seems further East on this run, with the sinker not amounting to much, its the secondary behind that im more concerned about.

Lovely mild sector from the LOW to the west now bang smack over all of England and Wales. No handbags out yet... But friday is a non-event on this run.

Looks identical to the 00z run to me near enough, with if anything the low stronger. Change of flow to a slightly more NW though maybe, in part due to the low strengthening.

Edit: does look like that small change is enough to make the temps borderline for anywhere but Scotland and Northern England.

Edited January 26, 2010 by cowdog

[Lewis]

Looks identical to the 00z run to me near enough, with if anything the low stronger. Change of flow to a slightly more NW though maybe, in part due to the low strengthening.

The LP deepens, and has a much larger core too it, with a W/NW flow (with warmer 850's inside and wrapped around it) So the result of this (if it verifies) would mean rain for everyone with some wintery precipitation over higher ground, then later in the day back edge snow for Central N england, and around the border of Scotland.