Model Output Discussion 19th January 2014-18z onwards.

[Gibby]

There doesn't seem to be any major cold blast of air modelled for the UK,but rather a steady descent into colder weather,as indicated when comparing the ECM ensemble mean charts for now and day 10.

 

now..EDM0-0.gif  day 10..EDM0-240.gif

I wouldn't disagree with that but that warm pool down to the SW is having a large say still even in 10 days on the limited spread of the cold to the NE.

[winterof79]

There doesn't seem to be any major cold blast of air modelled for the UK,but rather a steady descent into colder weather,as indicated when comparing the ECM ensemble mean charts for now and day 10.

 

now..EDM0-0.gif  day 10..EDM0-240.gif

Also if any system dares to track s/e a colder feed will wrap around it

http://modeles.meteociel.fr/modeles/gfs/runs/2014012112/gfs-0-192.png?12

http://modeles.meteociel.fr/modeles/gfs/runs/2014012112/gfs-1-186.png?12

[bobbydog]

 Err, quite, Gibby. Plus depth temperatures still not very low (versus very different scenario last year), so it would have to be something non-marginal other than at sufficient elevation. Anyway - I agreed with your earlier comments. It's been an utterly fascinating winter thus-far, albeit for all the wrong reasons for those affected by flooding. It's a personal view, but the polarised variance from last year has actually made it all the more compelling. I've no reason to think February will prove any less interesting and challenging.

 

so maybe just as polarised?... but certainly not boring.

from a 'wintry' point of view, this winter has been disappointing (so far... we still don't know what it might have in store yet!). however it has provided us with some insight into how the models deal with the weather itself and just how difficult forecasting can be. even if we end up with a snowless winter, hopefully we can all learn something from a fascinating (if frustrating) period of model watching.

[Cheese Rice]

Can someone guide me on what parameters aren't quite there for snow to fall at Thursday 9am?

 

Moderate precipitation 

 

 

 

Dew-point 0/-1.c

 

 

 

850's of -6.c

 

 

I'm at 200m ASL in central northern England (Leeds), I would of expected snowfall from this but the PPN type shows rain.

Edited January 21, 2014 by Cheese Rice

[gottolovethisweather]

Regarding possible snow at the end of the week, very good wet bulb levels and dew points.

But there is no precipitation that coincides with the above charts. Below is when there is and just isn`t happening on this GFS run.

 

Edit: I do want snow.

 

Hence those "in the know" are suggesting transient snowfall events, however I would personally happily take transient snowflakes for now. What we don't need is cold rain, yet alone mild rain. So far this season, the weather gods might be looking down on us and thinking we're returning to that once famous era which I dare not mention. Equally as time ticks on, they might be serving up another 2013 type Winter into Spring scenario. Either way, the charts generally show some interest at least for a few of us for something reminiscent of Winter.

Edited January 21, 2014 by gottolovethisweather

[Purga]

A much worse run for cold from GFS 18z coming up by the looks of it.

 

 

[Eskimo]

A much worse run for cold from GFS 18z coming up by the looks of it.

 

 

Looks more or less exactly the same as the 12z. 

[Barry Reynolds]

I rarely post on here, but I think the frequency of snowless winters varies greatly across the country. May be rare in Scotland, but not so rare in Devon away from the hills! We have been spoilt the last few years.

Anyway, that aside, I've noticed recent tweets about a possible SSW event in 15 days or so. Does anyone remember if the SSW last year was forecast correctly by the GFS? Sorry if this has already been covered....

[Jason M]

Cheese Rice

Maybe the issue is that the colder air is not embedded through the various levels of the atmosphere at that stage. Probably still some residual warmth.

[tight isobar]

The mid short lp will have major implication 18z mid atlantic south east for most Greenland.

[AWD]

Can someone guide me on what parameters aren't quite there for snow to fall at Thursday 9am?

WBFL at circa 500m+ for the majority of England still at that time;Thickness values for your part of the world touch and go too at that time still; Edited January 21, 2014 by AWD

[Cloud 10]

I wouldn't disagree with that but that warm pool down to the SW is having a large say still even in 10 days on the limited spread of the cold to the NE.

 

Can't see any warm pool at day ten,with 850 temps showing negative anomalies for

the UK?

 

[Panayiotis]

Can someone guide me on what parameters aren't quite there for snow to fall at Thursday 9am?

 

Moderate precipitation 

 

Dew-point 0/-1.c

 

850's of -6.c

 

I'm at 200m ASL in central northern England (Leeds), I would of expected snowfall from this but the PPN type shows rain.

1) The thickness chart for that time seems ok (I normally say that the 129/130 is a good approximate if you want to see snow (light blues))

2) There is no wet bulb temperature chart from the EURO4 (which is important in determining whether it will snow at a certain height) 

3)Given that there is no snowfall/rain type chart for 45hrs, how can you say that you wont see snow?

Edited January 21, 2014 by Panayiotis

[Ali1977]

Looks better to me, better heights over Greenland may slow the low over East Canada heading our way.

[TSNWK]

The mid short lp will have major implication 18z mid atlantic south east for most Greenland.

Good or bad for coldies..

[Mucka]

More amplfied to the West than the 12z but we need to low pressure move S/Se and clear into Europe effectively

 

 

That chunk of PV just wont give us an even break will it?

Edited January 21, 2014 by Mucka

[Gibby]

Can't see any warm pool at day ten,with 850 temps showing negative anomalies for

the UK?

 

EDM100-240.gif

I understand the point you are making but my point was that the Azores High which is as present as ever in 10 days time will have a big impact on whether we get into deep enough cold for what everybody wants to see and those slightly colder anomaly's for the UK you illustrate will most likely be achieved via polar maritime air from the NW rather than anything from the East. 

[Tim Bland]

18z looks ok to me. Atlantic ridge more amplified, helped by a semi split in the PV and heights over the arctic. Snow over high ground from strong flow north of west early next week. Let's see if we can get a proper Atlantic ridge and a decent northerly out of this run. Even if we don't get much snow is still like to see some entertaining model runs before this winter is out! Unless I have a bad memory it has been the worst winter for exciting model runs since I joined NW about 8 years ago. Either that or the models have become more accurate and so there is less eye candy

[gottolovethisweather]

 

 

 

In Summary there remains little chance of any significant dry weather over the course of the output tonight. There will again be plenty of rain in areas that could well do without it. For those looking for cold weather there seems little sign of that either tonight with the pattern that we have now remaining in situ for some considerable time to come. However, having said that the air that crosses the UK on the rear of exiting depressions could well be cold enough for some snowfall on hills, especially in the North but once more tonight there seems little sign of any meaningful cold and snowfall.

 

 

Whether people admire your summaries or not Gibby, your whole last paragraph sums things up perfectly right now, THANK YOU.

 

Onto other quoted posts which move away from Gibby's viewpoint slightly and nearer to my own. I believe the surprise element many have mentioned including myself, comes about from the fact given the Shannon Entrophy (trof-y, how pertinent  ) there is currently might not have any bearing on where we'll be, come the end of January. It could be a whole different ball game by then, I certainly hope so.

 

The issues for those of us wishing to see prolonged cold in the longer-term are numerous and I will pick up on those important facts quoted by others. The endless unrelenting Jet coupled with how it interacts with the Polar Vortex. Then you have the other factors which are beyond my knowledge range, the QBO and Mountain Torques, the actual synoptics up in the Arctic etc. Conversely, many positives can also be said of the fact that things Stratospherically and indeed NH wise are prone to a fair bit of chopping and changing as well in the coming days, some of which may in the end favour a colder spell than currently forecast. The Scandi High and the troughing over Central Europe bringing in the surface cold over there are two things to watch intently. No way is this man giving up on any manner of climatic possibilities and I suspect Gibby's updates will be chopping and changing, just like the models over the next few days and weeks right up until the end of meteorological Winter.

Edited January 21, 2014 by gottolovethisweather

[Geordiesnow]

At least the potential mild blast is getting shortened to more or less a day or two now and parts of  Northern and Eastern UK may not even get much in the way of mild temperatures but its looking very mild across some Western areas, temps could creep up to 12-14C I reckon.

 

That deep low being projected could be a concern if it strikes the UK that deep, I think this will be unlikely as all the mid latitude blocking will probably help keep the strongest winds away and will start to weaken it however its one to keep an eye on, the ensembles picked up on this recently and it has been mentioned in this thread that a deep Atlantic low could be on the way so one too keep a very close by on for sure. 

 

As for the cold potential, at least the GFS is now back on board in trying to split the PV in the Arctic, but of course unless an actual cold set up develops then its hard to get excited even though its fair to say, the chances for cold is higher than it was in December. 

[Purga]

Trouble is the LP to our north is phasing in with the Canadian vortex and enhancing the zonal westerly blast.

Positive is the split vortex and pressure heights over the pole but very frustrating that it won't do us any good at all at this stage.

[Troubleatmill]

More amplfied to the West than the 12z but we need to low pressure move S/Se and clear into Europe effectively

 

 

That chunk of PV just wont give us an even break will it?

Sploging its duff all over us mucka until there are fundamental changes over there I fear for us coldies

[Tim Bland]

It's so frustrating watching the PV get distorted and split and all the cold air spilling to low latitudes around the northern hemisphere.....everywhere except the UK! It really is bad luck. Look at the 850 uppers around the northern hemisphere next week! The USA is about to get "polar vortex part 2" as the media are calling it. At least Russia is getting the cold and snow for the winter games. We might all need to tune in and get our snow fix that way!

[nick sussex]

More amplfied to the West than the 12z but we need to low pressure move S/Se and clear into Europe effectively

 

 

That chunk of PV just wont give us an even break will it?

Yes sadly its a case of better upstream worse downstream, that bowling ball low takes so long to fill and sink se that even with the more amplified upstream pattern the energy still manages to attach itself, if you had the 12hrs downstream and this upstream you'd probably get the clearance of energy, but it seems to be what can go wrong will at the moment!

 

The ECM De Bilt ensembles  have solutions that are like the GFS 18hrs run downstream, the operational run is in the colder cluster for the 25/26 January before they converge once again, the actual blocking to the north and ne is better with the GFS 18hrs run but the low is too deep and round and poorly tilted.

[Joe Levy]

Based on the GFS 18z at 168 hours, there is a chance, and I say a chance because I don't like to preempt what runs will show, that the azores high will link up better with the Arctic high here, because the Arctic High is further south. So far that seems to be what is happening

EDIT and here at 186 hours we have this, which has a lot of potential to say the least

Edited January 21, 2014 by Joe Levy