Model Output Discussion - 23rd Jan - 12z onwards

[Cheshire Freeze]

very marginal, rain low levels?, to newbies, purples do not mean cold

With such low heights, 850 temps will sit a lot closer to the surface than they would otherwise. Dew points etc therefore would be reduced accordingly compared to the norm. Yes, still marginal but SK did a good post on this earlier.

[Ice Day]

No backdown from the ECM.  This at 144, looking great.

 

[Harsh Climate]

In which case, given we have fantastic charts within a week, why post it J?

Anyway, quite astonished by some posts this afternoon. Kris has explained why black is not white and yet some still protest that it is.

Also, IDO, why use the coastal snow signal when it's damn difficult to get coastal snow due to the SST evident. (Unless you are purely looking at coasts with no possible onshore wind vector in which case they will probably not show any convective potential)

All very confusing for me and I don't consider myself a novice. God knows what some of the new members and guests are thinking. I imagine poor JH on his fifth scotch looking up at the jungfrau pulling out whatever hair he can spare! Fortunately , he won't be reading this thread today!

 

If that post is causing you distress I suggest you go grab a cup of hot chocolate and take a time out. 

 

If someone wants to show a great chart showing what could happen (albeit most unlikely) then so be it, this is the model thread after all and let's face it, just about every chart posted is FI and just another very small piece of jigsaw that they churn out every 6 hours..

 

And I'm pretty sure ''poor JH'' will get over it..

Edited January 25, 2015 by Harsh Climate

[Day 10]

People can't be moaning over the uppers in this frame

 

[inghams85]

This! It's a very unusual set up with the low heights. Normal rules go out of the window. This could be a very interesting unstable snowy cold spell. The newsworthy aspect of Ian F's twitter post could well be snowfall. Troughs and fronts are almost guaranteed. IIncredibly unstable cold air

With such low heights, 850 temps will sit a lot closer to the surface than they would otherwise. Dew points etc therefore would be reduced accordingly compared to the norm. Yes, still marginal but SK did a good post on this earlier.

[Ice Day]

People can't be moaning over the uppers in this frame

 

.....give it time!

[Daniel*]

From what I've seen so far ECM 12z is superb following on 00z there's hardly any marginality whatsoever really impressive cold minima for the E on T144 chart, I would think under a really slack flow from the far arctic gates. Ian may be correct in saying it may be a notable spell of weather. Brimmed with potential.

[Cheshire Freeze]

168 hrs of ECM could possibly be one of the best charts of the winter going forward. Hint- look at sliding low to NW and amplification behind.

[Snow Grain]

People can't be moaning over the uppers in this frame

if you are talking Canada and the USA lol

[chris55]

ECM 168

 

[Day 10]

if you are talking Canada and the USA lol

Yes exactly! lol

[EML Network]

Solid agreement between the UKMO and ECM at + 144, leads one to think that the UKMO evolution wouldn't be too far away from the ECM evolution perhaps

 

UKMO + 144

ECM + 144 

GFS Op for comparison

JMA is more similar at + 144 but goes on to show the Azores High taking control a few frames later

 

 

GFS out on it's own at that particular juncture. 

 

But the Azores still sits there waiting to pounce , I can't even remember the last time that Azores high wasn't there, does it ever go away ???

[shotski]

Solid agreement between the UKMO and ECM at + 144, leads one to think that the UKMO evolution wouldn't be too far away from the ECM evolution perhaps

 

UKMO + 144

ECM + 144 

GFS Op for comparison

JMA is more similar at + 144 but goes on to show the Azores High taking control a few frames later

 

 

GFS out on it's own at that particular juncture. 

 

But the Azores still sits there waiting to pounce , I can't even remember the last time that Azores high wasn't there, does it ever go away ???

I think the clues in the name ?

[Harsh Climate]

Right here would be the south east's greatest chance of snow, shame it only looks a fleeting affair.

 

[shaky]

What a freezer of a run the ecm is!! Snow from Wednesday onwardw widely right until the end of the run!!hopefully it can build a stronger ridge in the atlantic between 192 and 240 hours tomorrow!!

[J10]

ECM pretty much duplicates its morning run out to day 5.

850s similar too. The pressure pattern suggest a front moving southwards later on Thursday and into Friday, this could produce an organised band of precipitation. (850s along the band look to be around -5/6C)

 

Northerly at day 6

850s on the fall again, Friday looks a little less cold with temperatures around 4-6C (this just going by the BBC forecast from earlier, this looks like the high point for temperatures). Turning cold or very cold from Saturday.

 Seems spot on analysis there.

[Harsh Climate]

What a freezer of a run the ecm is!! Snow from Wednesday onwardw widely right until the end of the run!!hopefully it can build a stronger ridge in the atlantic between 192 and 240 hours tomorrow!!

 

IMO the ECM is much closer to the GFS solution than the UKMO. It looks a lot scruffier and marginal albeit probably more chances of snow than the UKMO which to me looks a little dry away from northern scotland and coastal areas.

[snowice]

Solid agreement between the UKMO and ECM at + 144, leads one to think that the UKMO evolution wouldn't be too far away from the ECM evolution perhaps

 

UKMO + 144

ECM + 144 

GFS Op for comparison

JMA is more similar at + 144 but goes on to show the Azores High taking control a few frames later

 

 

GFS out on it's own at that particular juncture. 

 

But the Azores still sits there waiting to pounce , I can't even remember the last time that Azores high wasn't there, does it ever go away ???

IF there the same at 144, than how are they further apart? I would imagine ecm UKMO cross agreement between the two euros is a pretty big indorsement of a blast of polar artic air?

[Captain Shortwave]

Hmm

Not sure about whether the polar vortex will relocate to the Greenland sector with extensive blocking over Siberia. Given the stratospheric forecasts keep the polar vortex in the Euro sector.

Simple terms, I don't buy the day 10 output of flattening out the pattern.

Edited January 25, 2015 by Captain shortwave

[Cheshire Freeze]

Well we don't get the toppling ridge into scandi this time but it's something to watch out for in future output post Scandi troughing.

Edited January 25, 2015 by CreweCold

[Banbury]

What a freezer of a run the ecm is!! Snow from Wednesday onwardw widely right until the end of the run!!hopefully it can build a stronger ridge in the atlantic between 192 and 240 hours tomorrow!!

I'm certainly not sure about using the word 'widely',

[Geordiesnow]

I'm certainly not sure about using the word 'widely',

 

And I'm not sure whether I will use the term "freezer" either, the ECM is okay but nothing what I would say all thate noteworthy in all honesty. 

 

Obviously there has been much debate regarding 850 temps and low thicknesses in how lower thicknesses could mean 850 could become less of an issue but looking at the ECM, I'm not sure you will get all that low temps on that 120 hours chart for example especially during daylight hours. However in general, the theme has not changed but the detail has and no doubt this will keep chopping and changing, although the signal is only small, it would be good to get at least a decent enough Atlantic block, it can only help to sustain the Northerly for longer. 

[bluearmy]

The raw data on ECM has quite a few occasions where Dp shows positive, especially midlands south - these almost always tie into when there is something decent qty wise falling from the sky. judging from last week, the DP's are a better guide than the snow cover charts. anyway, I agree that the 12z ECM is more marginal for snowfall than yesterday's charts but I would still expect quite a lot of snow to be falling from that run. How much of it delivers low level lying snow would be the question.

The end of the run is surely over progressive over the polar field

[blizzard81]

What a freezer of a run the ecm is!! Snow from Wednesday onwardw widely right until the end of the run!!hopefully it can build a stronger ridge in the atlantic between 192 and 240 hours tomorrow!!

Yes, we need to see that trend tomorrow but without the assistance of an arctic high, that is going to be a tall order. The good news is that there is plenty of time for this trend to emerge as we are still talking 8 days plus away.

Edited January 25, 2015 by blizzard81

[nick sussex]

Still a  lack of agreement between the outputs regarding the Euro troughing, the UKMO is by far the best, the GFS is underwhelming although it has more promise later.

 

The issue remains the lack of any blocking although at least the GFS tries to develop a decent high pressure to the nw, the best opportunity IMO to get some deeper cold in is through a ridge like the GFS extending further ne, that might still happen regardless of the quite progressive ECM operational run.

 

In terms of dew points and the infamous GFS snow precip charts at longer range these are wildly innacurate, some other parameters might look good for snow but I'd urge caution until nearer the time.

 

With this static type pattern with the Euro troughing it can throw up the odd surprise but I think its a case of being patient till nearer the time. Because we're not dealing with a deep cold flow its difficult to call snow at 5 days out.