Model output discussion 24/01/21

[sheikhy]

Best thing is it all starts from this saturday

[winterof79]

4 minutes ago, sebastiaan1973 said:

Please read Nick F's comment earlier this morning.

Your diagram has NO Iberian low and why should I read his comments on it being an outlier of sorts. 

[sebastiaan1973]

Just now, winterof79 said:

Your diagram has NO Iberian low and why should I read his comments on it being an outlier of sorts. 

The iberian low is at the included chart.

[winterof79]

23 minutes ago, feb1991blizzard said:

Only slight problem with the Para is its highish heights, so limited PPN, clouds would be topping out quite low.

At what timescale are you predicting these clouds to be topping out low as you didn't refer to one. Thanks

[winterof79]

4 minutes ago, sebastiaan1973 said:

The iberian low is at the included chart.

That's a low? Whats that going to prop up? 

 

[Griff]

19 minutes ago, IDO said:

The para has been very west based in FI of late, so not a preferred solution for IMBY. Last two runs:

 

Surely preferred solutions is a different thread to model watching?

... But I 100% get what you're saying

[feb1991blizzard]

5 minutes ago, winterof79 said:

At what timescale are you predicting these clouds to be topping out low as you didn't refer to one. Thanks

The timescale by where you have easily cold enough 850's, so the lapse rates are good up to a few km's off the ground, but you have the yellows and very pale greens on the feed from the Easterly into us, so the mid level lapse rates wouldn't be steep to allow big dumpings, could be some decent graupel though but no big dumpings from that.

GFS easily better than para but a more long winded way to get there in other words.

Edited January 28, 2021 by feb1991blizzard

[sebastiaan1973]

1 minute ago, winterof79 said:

That's a low? Whats that going to prop up? 

 

Please read Nick F comment about it

[BLAST FROM THE PAST]

15 hours ago, BLAST FROM THE PAST said:

Want to come back to this....here is today’s ECM at t120 which was the t168 in above post.

looks so much better doesn’t it ?

Here is the t168 from Monday

BFTP

And today it will be t96

look at the difference......it appears to have been way too progressive.  Let’s hope that it has got it more right now at t96.

 

BFTP

 

[That ECM]

More gefs on board I would suggest.

[BLAST FROM THE PAST]

If we get here as per GFS 06z para at t240

 

had to post this due to all the -12s

I can’t see it collapsing so quickly to this by t288....even though synoptically it’s within the mix....it’s too fast for me IMO 

 

BFTP

 

Edited January 28, 2021 by BLAST FROM THE PAST

[Battleground Snow]

Just now, That ECM said:

More gefs on board I would suggest.

Very big improvements from the 00z run 

Graph form is diving

[johnholmes]

The 500 mb check I promised

Thursday 28 January

Ec-gfs and this morning both show something ec had yesterday, suggesting ridging over/ne of Iceland. Near the uk and there is little flow on either, the strong w’ly showing for several days has gone with a sort of flabby trough in the uk area. In the far w of the charts the trough-ridge pattern is kept but is a bit far west, I think, to generate a similar pattern downwind, but we shall see.

Noaa 6-10 last evening and its w’ly flow over the uk continues to decrease. In the far west the trough ridge pattern remains, much as the last couple of days, again a shade too far west to be conducive to replicating downwind yet? There is just a slight sign of ridging in the Iceland area. On the 8-14 this is much more marked and there is also a +ve signal for height rises between Iceland and Jan Mayen. Looking again at the n America pattern and there is marked troughing down the middle of the continent. An interesting set of charts with perhaps some hint of a change in the wave length pattern over the eastern Atlantic and Europe-too early to have more than a 30% belief it will happen!

The ECMWF outputs suggest the north of the uk staying cold with the colder 850 air edging south then north in the different time scales out to day 10 from now. Also some suggestion in the 850 wind flow of a combination of a marked low in the far ne and a ridge just west of it.

Best wait and see how these charts all develop over the next 48 hours.

ECMWF/GFS DAY 8-10 MEAN 500MB HEIGHT COMPARISON

WWW.METEO.PSU.EDU

Climate Prediction Center - 6-10 Day 500mb Outlook

WWW.CPC.NCEP.NOAA.GOV

These are ECMWF 500 and surface charts on this link

http://www2.wetter3.de/Fax/00_ECMWF_ENS_p0_500hPa+144_240.gif

and another link into ECMWF charts

http://meteocentre.com/numerical-weather-prediction/

[Cloud 10]

Even the ensemble means at 360hrs are stonkers today!

GEFS and GEM

[Ali1977]

I just read pages 62/63 and it’s all about the latest GFS being an amazing run for coldies - surely a sign

[Matt H]

The GEFS 06z ensemble mean is now down to around -7C by the 6th February compared to a mean of -5C on the 00z suite. Plenty of runs going colder than this as well. Progress!

Edited January 28, 2021 by Frosty Winter

[Methuselah]

My, what a stonker the 06Z is! Even right at the death (Yes, I know it's @T=384, and probably won't verify!) But, what if it did?!

    

Mustn't get too carried away!

[Boro Snow]

[sheikhy]

10 minutes ago, Battleground Snow said:

Very big improvements from the 00z run 

Graph form is diving

Expecting the milder bunch between the 2nd and 3rd of feb to get flattened out on the 12zs if everything goes according to plan!!!

[MJB]

Control at 276h looks v good to me 

[snowking]

I haven't had much time to look into things too extensively lately with a heavy workload.

So we're in the period of the last third of Jan that I and many others had hoped would bring some significantly wintry weather to the UK's shores. And whilst many of us have been lucky enough to see snow, and indeed through the rest of this week that will continue to be the case, there is no dressing up that the 'big boom' winter synoptics we would have hoped for during this period, courtesy of our SSW, have not come fully to fruition.

In truth I think we have been desperately unlucky, given the synoptic setups we have seen, to have had such a warm early season across Europe so as to prevent something which in previous years, with similar synoptics, would have delivered far more. A lesson learned here that even though we saw some temporary splitting of the stratospheric vortex at various junctures following our huge Wave 1 displacement event, Wave 2 led vortex disruption events and their (usually) consequent far more significant splitting of the stratospheric polar vortex offers probably a greater chance of something more significantly wintry in our part of the northern hemisphere.

All of this being said, the stratospheric warming episodes which have already occurred, and the one due to occur once again over the coming days, have already done lasting damage to the stratospheric vortex, and left our tropospheric vortex in relative tatters compared to other winters in the past 25 years - here's an example of where we are this year, vs where we have been in previous years (2019/20 used as the example here)

So, the stratosphere has done its part (as much as it can given the dynamics this year), and left us with a relative void of westerlies at northern latitudes throughout the stratosphere and troposphere, as demonstrated nicely here on the ECM op day 9 zonal wind profile

Over to the troposphere now to play its part. There have been two things we have been sorely lacking in from what I can see from a tropospheric perspective (and the cause of this is still to be hotly debated - at the moment, La Nina seems to be the most mooted contender, particularly when taking tropical influences, or lack of, such as the MJO into account - we'll leave this for another time) - positive global angular momentum through January, and assistance from the tropics. Well, we may be about to get both.

Relative angular momentum tendency seems to be on the way up, the screenshot below taken from Ant Masiello over on Twitter as I've lost my links through to such analysis (if anyone is able to help with the links to where these now live that would be greatly appreciated!)

The net result of which we would expect to be a much more ridgy/troughy longwave pattern - think plenty of opportunity for blocking highs to occur.

Then the second, very well advertised ingredient which may be able to ride to our rescue and allow the troposphere to take advantage of the relative lack of westerly momentum imprinted from the stratosphere above, is the MJO movement through to phases 6 and 7. I wont re-post these as they have been very widely covered in here already, but let's keep in mind that phase 6 would tend to suggest high pressure at slightly lower latitudes than phase 7 in our vicinity at least.

So where does that leave the thinking for the 2 weeks ahead? My punt at this stage would actually be something very akin to the recent GFS para output, such as this at day 10:

Main features for me are:

1. Would expect more of a high pressure cell close to the N of the UK - Norway through to Iceland, somewhere close to that. What that probably means initially at least is something much colder and drier for many (probably welcome relief in flooded communities).

2. As we transition from MJO phase 6 through to 7, expect any high pressure to gain latitude with time. This should allow for something a little more interesting as time goes on in terms of snow potential.

I would also be suspicious of any model output promoting anything too west based in terms of the NAO at this stage too - it's more of a hunch than anything, but given the relative lack of momentum in either direction currently, along with the likely uptick in angular momentum, I can see that with movement from MJO phase 6 and 7 the opportunity for high pressure to move further North with time, but I'm not sure where the forcing would come from for drastic retrogression of any blocking pattern within the next 14 days.

Final note from me - this sort of ensemble mean suggests huge potential to advect some very cold air from East to West through Europe - there's a reason @nick sussex loves a Genoa low (although this may leave us just a little short of that).

Angle/alignment of such features all still very much to be worked out, and plenty that can still go wrong in the shorter term to prevent us from even arriving at the sort of destination currently modelled through days 8-10 (and as we know from this winter already, anything that can go wrong for UK cold generally will). But with both Troposphere and Stratosphere now doing everything they can to move us towards something seasonal, this feels like our best chance yet.

 

 

[MJB]

Even with this system sliding down the cold air remains 

And at 264h

[Turnedoutniceagain]

MetO now onboard at T-48

 

[MJB]

And BINGO the Control is stunning

[MJB]

2 minutes ago, Turnedoutniceagain said:

MetO now onboard at T-48

 

Looking good for West and North Oxfordshire ..........................I hope