Model output discussion - into Christmas

[Don]

1 minute ago, swfc said:

EC gone at 192 hours.the heighths to the south and the northern arm of the jet are repeating the same output on the nhp

Cannot stop those heights to the south!

[Mike Poole]

2 minutes ago, swfc said:

Oh I take your point but what inclines you to go with the gem.even at that short time scale all models arnt going to be identical!!

I'm not going with the GEM, I'm just pointing out it is a decent model and that is what it shows.  I tend to see the various op runs as a kind of super ensemble, and draw my conclusions that way, in general the pecking order is ECM, then UKMO, and GFS and GEM equal.  There is massive uncertainty with the current setup, and will require more runs to resolve.

[SLEETY]

Hopefully the models are over doing the rise of pressure to the South,they have done it enough times with high pressure over scandi and Greenland ,where the pattern nearly always flattens out to nothing !

[ICE COLD]

Day 10 on the ECM looks good but ............. are leave u all to fill in the blank . Such a struggle to even get even a half decent cold spell in this country

[Ali1977]

1 minute ago, ICE COLD said:

Day 10 on the ECM looks good but ............. are leave u all to fill in the blank . Such a struggle to even get even a half decent cold spell in this country

But it’ll verify way better than this?

Another one showing HP pulling West away from Europe then heading north, could this happen, and if so what’s driving it I wonder!! 

[LRD]

16 minutes ago, Ali1977 said:

But it’ll verify way better than this?

Another one showing HP pulling West away from Europe then heading north, could this happen, and if so what’s driving it I wonder!! 

Yes, ECM at 240 finally provides us a chart that provides a bit of light at the end of the tunnel after 48 wretched hours of model watching. We'll have to go through a bit of pain to get there but we can only hope that short term pre-New Year pain results in January gain

[Mike Poole]

16 minutes ago, Ali1977 said:

But it’ll verify way better than this?

Another one showing HP pulling West away from Europe then heading north, could this happen, and if so what’s driving it I wonder!! 

Well one driver could well be the MJO at that range, favourable phases for northern blocking are 7-8-1, and GEFS has us headed that way:

ECM more coy, but it is a trend to watch:

For newbies, the MJO is a predictable pattern of tropical convection that moves through various locations as per the diagrams above, and can influence the wave pattern in our neck of the woods down the line.  

[LRD]

8 minutes ago, Mike Poole said:

Well one driver could well be the MJO at that range, favourable phases for northern blocking are 7-8-1, and GEFS has us headed that way:

ECM more coy, but it is a trend to watch:

For newbies, the MJO is a predictable pattern of tropical convection that moves through various locations as per the diagrams above, and can influence the wave pattern in our neck of the woods down the line.  

I might be wrong but I'm sure ECM was in the circle of death* over the last couple of days so some progress.

 

*or was it GEFS?! Either way, signs of improvement as long as that's been modelled accurately

Edited December 21, 2019 by LRD

[Mike Poole]

1 minute ago, LRD said:

I might be wrong but I'm sure ECM was in the circle of death* over the last couple of days so some progress.

 

*or was it GFS?! Either way, signs of improvement as long as that's been modelled accurately

Correct ECM was in the COD, GEFS showing more amplitude, and the difference is still there, but they are closer now I think, as often what actually happens will be somewhere in between! 

[LRD]

2 minutes ago, Mike Poole said:

Correct ECM was in the COD, GEFS showing more amplitude, and the difference is still there, but they are closer now I think, as often what actually happens will be somewhere in between! 

Thanks

It's something to watch though. Will ECM move towards GFS or vice versa? Or, as you say, will they meet in the middle? At least we have a positive to cautiously cling on to for now

[Kirkcaldy Weather]

32 minutes ago, Mike Poole said:

Well one driver could well be the MJO at that range, favourable phases for northern blocking are 7-8-1, and GEFS has us headed that way:

ECM more coy, but it is a trend to watch:

For newbies, the MJO is a predictable pattern of tropical convection that moves through various locations as per the diagrams above, and can influence the wave pattern in our neck of the woods down the line.  

Hi Mike, obviously I have made my thoughts clear recently with my attention being on the feedback from phase 3 ie higher pressure of some variety, but just wanted to point out that although the diagrams show MJO in COD phase 4 conditions have been present the past few days http://www.bom.gov.au/climate/mjo/graphics/rmm.74toRealtime.txt    which suggests the higher pressure moving more out west and possibly lower pressure across Scandinavia with some higher pressure toward Barents / Kara Sea although like phase 3 this might be brief but will continue to monitor MJO progression.

[SLEETY]

Interesting that ECM op was a mild outlier at the crucial timeframe of 5 days ahead on boxing Day.

That's the period where I think the models are still struggling,maybe not all over yet.

Edited December 21, 2019 by SLEETY

[carinthian]

Interesting UKMO extended at 168t. Completely different to what the other models are showing. Not sure how to view this with limited synoptic scope but seems to show retrogression of the ridge and cutting off any Tm airmass into the British Isles. A chink of hope !

C

Edited December 21, 2019 by carinthian

[MATTWOLVES 3]

Ecm mean not great at face value. The mean still above freezing, but out to day 14 is does tend to fall away further. Hopefully a new trend setter! Lovely little ensemble from the GFS 12z in lala land... January 3rd....potential little snow maker.... Never say never, as slim a chance has it seems... I bid you good evening... Keep up the chase.

 

 

Edited December 21, 2019 by Mattwolves

[SMU]

Evening All

If I had just logged in & only seen the UKMO tonight I would have said things hung in the balance - Also 168 UkMO shows a potential snow event for the North

Lets see what model is correct

UKMO / GFS ( & 18z ICON ) neg tilted ridge > Good ( or at least better )

ECM pos tilted poor ridge > 

My eggs always in the UKMO basket.

[SMU]

14 minutes ago, carinthian said:

Interesting UKMO extended at 168t. Completely different to what the other models are showing. Not sure how to view this with limited synoptic scope but seems to show retrogression of the ridge and cutting off any Tm airmass into the British Isles. A chink of hope !

C

Yes just saw this & if you look at 144 chart plenty of cold to tap just to the North...

[Purga]

15 minutes ago, carinthian said:

Interesting UKMO extended at 168t. Completely different to what the other models are showing. Not sure how to view this with limited synoptic scope but seems to show retrogression of the ridge and cutting off any Tm airmass into the British Isles. A chink of hope !

C

Similar to the ECM at +168 isn't it?

[Mike Poole]

ICON T90:

There needs to be room to squeeze a ridge behind that annoying shortwave w of Ireland.

[KyleHenry]

2 minutes ago, Steve Murr said:

Yes just saw this & if you look at 144 chart plenty of cold to tap just to the North...

CWB to curve up to Greenland and back towards the eastern US. The lack of TPV and energy contained inside the wave break on the UKMO 168z. HP may not hold for long over Greenland but cold air down through the UK and retrogression of HP towards Scandi a likely outcome. 

[ICE COLD]

6 minutes ago, Purga said:

Similar to the ECM at +168 isn't it?

No there’s low pressure slap bang over the UK on the UKMO and a ridge behind it ( well that’s how I see it anyway ) . As Steve m says maybe snow on its northern edge . 

[carinthian]

9 minutes ago, Steve Murr said:

Yes just saw this & if you look at 144 chart plenty of cold to tap just to the North...

Yes, there is and the UKMO fax has the 528 dam line over Northern Scotland at 120t. Shame we have no access to upper air data at in relation to the 168t extended or even synoptic profile to the NE. However, an interesting chart, just wondering if that warm front forms into a low along the baroclinic boundary as this will be quite pronounced across Central Britain by that time. Just a thought to why this development has been shown. Maybe be gone in the morning !

C

[Catacol]

7 minutes ago, IDO said:

JFF as post-D10 could be anything, but better than the 06z:

Probably the two ends of the spectrum? The main takes are no Arctic High so the tPV more a player and still the Pacific Ridge MIA.

...and illustrating perfectly the difficulty NWP is having at present unravelling the upstream forcings going on. Far bigger brains than mine are interpreting the current MJO COD transition as a model best fit to a wide range of convection signals across the pacific equator that makes normal phase forecasting near impossible. And into this we need to factor the truth of a transitioning QBO, weakening +IOD event plus usual climatology for December. How many winter cold scenarios kicked off before Xmas over the years if we take out 2010? 

Faint hopes of a resilient block I think are becoming fainter - wise money would be on the block slowly becoming flattened as we move into January. A return probably to a more NW air flow and then eyes on the next opportunity for proper cold....in the second half of January. 

 

[damianslaw]

2 hours ago, Ali1977 said:

But it’ll verify way better than this?

Another one showing HP pulling West away from Europe then heading north, could this happen, and if so what’s driving it I wonder!! 

I commented earlier today on the Cold Air Advection on the eastern flank of the building euro high, a deep long wave trough developing through Scandi, and cold pool, this forcing therefore causes the high to quickly ignite west and retrogress through mid atlantic - barely a 48hr SW feed shot, and thereafter something much colder and cyclonic from the NW. Both ECM and GFS are showing this scenario as we approach new year. Many are focusing on christmas right now, quite rightly, but there are firm building blocks developing that are not conducive to a locked in SW mild fest. 

Back to the shorter term, this feature being shown for Boxing Day causing lots of headaches, its still there,but at this range far from clear how deep it will be and where it will develop. Thankfully the models are still showing a drier picture for Christmas Eve and Christmas Day, quite chilly and perhaps a touch of frost, so seasonal at least, without anything especially cold or snowy, I will take that over a wet soaking or blast from gales.

[SMU]

GFS heading towards UKMO at 120... nice flow of NE winds sinking SW west of Scandi & the atlantic low has more disruption heading ESE over the UK..

Edited December 21, 2019 by Steve Murr

[Jordan S]

Just for interest purposes the Nasa model early this morning began building high pressure over us for Christmas and beyond with it then ridging north into Scandinavia during the 28th and 29th allowing a cold northeastly flow with a few wintry/snow showers peppering Eastern areas. But not lasting long with the high moving back south over the uk by the 30th bringing calm dry and frosty conditions. 

Edited December 21, 2019 by jordan smith