Model Output Discussion 29th December - Into mid-Winter.

[Polar Maritime]

Not much change from the models this morning, With cold Pm shots next week. Very cold -10/11/12c uppers over the UK by Friday are certainly not to be sniffed at.. Plenty of room left for minor adjustments but certainly a wintry flavour as we head into next week.

 

 

 

Edited January 6, 2017 by Polar Maritime

[snowice]

Oh Dear i must be reading the wrong thread,-8 Uppers on ECM GFS for 168hrs snow showers in a lot of places.

It is the British isles members expectations are to high, i thought  a heatwave was coming after i read some of the posts.

Chin up loads of potential in the coming week with first chance of snow for many

 

 

Edited January 6, 2017 by snowice

[knocker]

The ext EPS this morning at day 12 is not good news for those of a cold persuasion  The upstream pattern change has taken place with an active Canadian vortex extending SW across Alaska and the Aleutians But also with a trough in the NW Atlantic which, coupled with some ridging over the UK backs the upper flow westerly. The trough tends to nudge east so the flow may back a tad more and the temps will thus return to average.

[snowy weather]

19 minutes ago, snowice said:

Oh Dear i must be reading the wrong thread,-8 Uppers on ECM GFS for 168hrs snow showers in a lot of places.

It is the British isles members expectations are to high, i thought  a heatwave was coming after i read some of the posts.

Chin up loads of potential in the coming week with first chance of snow for many

 

 

It's at 168 hours though. Never gonna come off.

[bluearmy]

Knocks had told you re the eps

looks like a mid lat high for most of us - makes a change !

after the brief incursion of cold of course 

 

Edited January 6, 2017 by bluearmy

[snowice]

1 minute ago, snowy weather said:

It's at 168 hours though. Never gonna come off.

IF it were just GFS I would agree with you, the fact ECM GFS are similar i have my fingers crossed its not like mad FI 

7 days away!

[radiohead]

Check out the 0Z GEFS members at T168-T180. A variety of different patterns and very few that look like the 0Z Op evolution. Quite a lot of the members show low pressure, maybe intense low pressure, close by or directing diving over us. This is something which could appear on the 06Z or 12Z runs today. I'm expecting more changes....

[Frosty.]

3 minutes ago, knocker said:

and the temps will thus return to average.

Lots of uncertainty further upstream..but the good news is a cold outbreak looks a reasonable bet for later next week.

[knocker]

32 minutes ago, Alekos said:

How is it looking for Greece ? ! I'm thinking the trend is for strong Northern jet and milder for NW Europe ? 

Oh..Oh...Oh....................

[bluearmy]

10 minutes ago, knocker said:

Oh..Oh...Oh....................

He was asking re the 46

cant say I noticed 

[knocker]

Just now, bluearmy said:

He was asking re the 46

cant say I noticed 

Oh right, nor did I.

[mb018538]

All we will get from a cold PM NW'erly outbreak is plenty of snow over the higher ground, a little to lower levels in the NW, and nothing down this way. Blink and you'll miss it stuff really. I agree with other posters in that everything is tilted in just the wrong place for the UK, so we're not going to see anything lasting or meaningful for now. Best get looking for the next window of opportunity!

[bluearmy]

It looks as though the Canadian segment is going to end up closer to w Greenland than looked the case a few days ago

that makes any meaningful amplification far enough to our west to be unsustainable and it seems a MLB close to our shores the most likely outcome 

for coldies, the best hope is for the high to ridge across to our ene and an easterly to result. Unlikely but not impossible 

 

[Frosty.]

chin up coldies, we have had some crisp frosty weather this week and next week, some of us will see snow if the models are anywhere close..

P.S.. watch out for icy patches across the SE this morning as showers fall onto frozen surfaces.

Edited January 6, 2017 by Frosty.

[frosty ground]

7 minutes ago, bluearmy said:

It looks as though the Canadian segment is going to end up closer to w Greenland than looked the case a few days ago

that makes any meaningful amplification far enough to our west to be unsustainable and it seems a MLB close to our shores the most likely outcome 

for coldies, the best hope is for the high to ridge across to our ene and an easterly to result. Unlikely but not impossible 

 

I have not seen anything other than a Atlantic High slight displaced north of the Azores that occasionally moves to allow a polar North Westerly...... and that'll do me.

HLB and Easterlies..... Just not gonna happen. 

[TEITS]

Disappointing 0Zs.

I mentioned last night the ECM has a tendancy of over amplifying and this morning we see a much flatter pattern. My fear is after the brief NW,ly outbreaks we might see high pressure settling to the S of us centred over N France. As a result milder W,lys but settled with the exception of the far N of Scotland. The only straw to clutch is a very small risk of an E,ly developing but im doubting the high can be far enough NE to benefit us in the UK.

[Summer Sun]

UKMO extended shows winds shifting more north to north westerly by Friday 13th

[weathermadbarnsleylad]

I posted last night about been led up the garden path and would leave anything forecast now for late next week with a pinch of salt only the  18z last night and now the 00z this morning push the pattern forward too quick by this time Sunday it will probably just be a blink and you will miss affair the high wants to do one fast or move to a worthwhile position hope for upgrades that slow the pattern down and brings in stronger northerly I think once we can get the cold in far enough south it could stay longer eventually we will have confidence in a cold prediction from the models but at the min not happening. 

[bluearmy]

The trend remains low height anomolies to our  south - just too far south because the northern arm flattens the Atlantic too much

suspect the London temps will still look suppressed in an hour  

[Singularity]

Amidst the model madness - where this sudden increase in mobility has come from I can hardly imagine - I've noticed one thing of interest;

For days now the GEFS projection has taken GLAAM over toward 7/8, yet each new observation keeps it in 4/5. This suggests to be that the tropical activity into the Pacific (phase 6) suggested by recent Hovmoller plots is having more of an effect on the pattern than this model at least is expecting.

So there's some scope for reversing the mobility trend over the U.S. Otherwise, a 1-3 day cold spell seems to be on the cards, though it may prove a bit mediocre for the south unless a disturbance in the flow can develop in the right place and without too much of a warm sector.

[Alekos]

10 minutes ago, Summer Sun said:

UKMO extended shows winds shifting more north to north westerly by Friday 13th

Maybe I read it wrong but that is WNW ?!

[Nick F]

Morning,

With a pretty strong jet ramping up next week, we are at the mercy of NWP modelling the timing and spacing of the shortwaves within in the jet correctly, which in turn affects developments of secondary lows at the surface. So perhaps wise IMO not too get too involved emotionally with the  evolution with each high res run past t+144 (or perhaps earlier?!) to avoid the inevitable downer - as we have seen yesterdays 12z EC vs today's 00z EC high res.

The swings between yesterday's 12z EC high res and today's 00z EC high res IMO lie with the spacing and number of waves in the jet,

For example, yesterday's 12z EC has two shortwaves in the jet next Friday 12z, one passing across the N Sea the other way back over Hudson Bay, the wave  in the jet over N Europe slows while upstream carries on and thus amplifies the flow to give us a northerly

However, on this morning's 00z EC, we have an extra wave in the jet as per diagram below, which doesn't allow the amplification and the straight northerly as like the 12z yesterday.

There is a possibility that these waves may not be modelled correctly yet, number and speed. The 00z GFS similarly has two waves in the jet close to each other over the N Atlantic - which doesn't allow anything more than cold NWly shots or perhaps the briefest of northerlies

A pretty flat upper flow pattern upstream in the medium to extended range on 00z GFS and EC high res and ensembles, as the N Pacific ridge disappears off the scene and is replaced by an upper low - though it does appear the 500mb vortex over Greenland and Iceland does retract west - but only to allow mid-latitude HP again - as Knocker and bluearmy have pointed out.

Still plenty of wintry potential from the NW cold shots, with a few surprise snowfalls not out of the question away from the  favoured northern and western hills - particularly overnight periods, but snow probably not sticking long away from hills.

Edited January 6, 2017 by Nick F

[Seasonality]

ECM 00z seems to be on the milder side of its ensembles from 192h so perhaps changes still possible. Also a comment for @Alekos, not the EC46 sorry, but I noticed GFS 00z FI shows even more cold into South East Europe. Something that keeps showing in the output in various forms. Every chance for the vintage Greek winter to continue I'd say.

[Alekos]

1 minute ago, Seasonality said:

ECM 00z seems to be on the milder side of its ensembles from 192h so perhaps changes still possible. Also a comment for @Alekos, not the EC46 sorry, but I noticed GFS 00z FI shows even more cold into South East Europe. Something that keeps showing in the output in various forms. Every chance for the vintage Greek winter to continue I'd say.

Thank you ! Yes more chances for us down here

[radiohead]

Heavy rain turning to snow in Scotland by T150 on the 06Z GFS

Colder uppers than on the 0Z at T156

By T162 there is still rain in the south but quite snowy further north and west.

T168...snow all the way down to the south.

Edited January 6, 2017 by radiohead