Model Output Discussion 01/09/17

[Cheshire Freeze]

1 minute ago, Ali1977 said:

Now then, this WOULD put the UK into the freezer a day or two later!! What a set up, just shane its in FI 

But with support from GEFS (at present)

[northwestsnow]

3 minutes ago, January Snowstorm said:

I see things rather differently this morning. Mid range has energy going over the top and we're left with milder air steadily moving down over us. Perhaps there is a trend for a rather strong Greenland high in FI but sure isn't that purely fantasy land at the moment 

The 00z runs look great to me JS..cold cold and more cold ...

[Cheshire Freeze]

Oh and here is the DAY 16! mean anomaly from the GEFS

Latest December CFS run (quite a flip from what it had been showing)

Still way too early to get excited though. Plenty of time for it all to come crashing down around us!

Edited November 25, 2017 by CreweCold

[northwestsnow]

4 minutes ago, CreweCold said:

Oh and here is the DAY 16! mean anomaly from the GEFS

Latest December CFS run (quite a flip from what it had been showing)

Still way too early to get excited though. Plenty of time for it all to come crashing down around us!

Already got a dusting after some lovely snow showers this morning think thats as good as all last winter!!!

Ec/Gfs both sniffing out the block bringing cold frosty weather then the block eventually retrogresses to Greeny....

Whats not to like

[mother nature rocks]

4 minutes ago, CreweCold said:

Oh and here is the DAY 16! mean anomaly from the GEFS

Latest December CFS run

It doesn’t look like the blocking is going anywhere fast if that 16 day GEFS is to believed, which would be a huge result for us!!!!

[knocker]

Anyway putting aside the fine detail the ecm is pretty much in the same ball park as the gfs up until the weekend. here it diverges although it does nod in the same direction as the gfs and has energy shooting out of north east North America across Greenland which does flatten (not through though)  the ridge quite quickly and eventually relegating the high pressure to the south west. This allows the Atlantic a route and allows troughs to track east from the north west which could well produce gales in the north whilst returning temps to around normal

This one of the possible scenarios that one could deduce from last night's anomalies

EDIT

I'm wondering why I keep getting different outputs to everyone else. It can only be a conspiracy methinks

 

Edited November 25, 2017 by knocker

[ArHu3]

17 minutes ago, mother nature rocks said:

It doesn’t look like the blocking is going anywhere fast if that 16 day GEFS is to believed, which would be a huge result for us!!!!

I'm on mobile, so I could just see the standard deviation map of the the ensemble , over there something odd happens too: uncertainty in the model first increases but then starts decreasing again towards the end ?

 

 

Edited November 25, 2017 by ArHu3

[Captain Shortwave]

Well good agreement on us seeing a convective northerly from the middle of the week onwards so areas closed to exposed coasts should see some heavy showers which could have sleet and snow mixed in (especially away from the coastline).

Day 5 charts

     

Beyond that, once that arctic high link up goes we see pressure fall rapidly towards Greenland, the resultant low then runs over the ridge and potentially feeds into the trough over Europe with the next push of heights in the Atlantic. The broad theme is there are the anomalies show, just the details still look sketchy. We could hold a northerly for a lengthy period, high pressure could nove over the UK or towards Scandinavia (cold easterly). 

The GFS and ECM charts show the differences in route detail here

   

GFS has that wedge of heights with the split flow developing later, the ECM tending to move high pressure towards us briefly with the retrogression route already being teed up.

I guess if we lose that arctic high linl up I would prefer the Scandi high option as once pressure falls towards Greenland then sometimes fullly clearing those low heights can sometimes prove difficult and tends to be handled poorly by the models. In the end i expect largw variation in the solutions for next weekend onwards until the trough/ridge interactions upstream are sorted. Best news is the better UKMO this morning which seals that initial convective northerly late next week.

Edited November 25, 2017 by Captain Shortwave
Charts added

[Matthew.]

7 minutes ago, knocker said:

Anyway putting aside the fine detail the ecm is pretty much in the same ball park as the gfs up until the weekend. here it diverges although it does nod in the same direction as the gfs and has energy shooting out of north east North America across Greenland which does flatten (not through though)  the ridge quite quickly and eventually relegating the high pressure to the south west. This allows the Atlantic a route and allows troughs to track east from the north west which could well produce gales in the north whilst returning temps to around normal

This one of the possible scenarios that one could deduce from last night's anomalies

EDIT

I'm wondering why I keep getting different outputs to everyone else. It can only be a conspiracy methinks

 

 History is against mild outputs for December Knocker. Wait till January when things will possibly flatten out

[bluearmy]

Awaiting the eps with interest but the direction of travel seems pretty set now. the consistency of the extended ens around mid Atlantic and even greeny ridge later week 2 is reminiscent of 2010 or 2009.  So we wonder if this weeks sceuro trough can bring anything unusually wintry to the uk (probably not re snowfall though by no means a done deal) and then the transition to further amplification later week 2 is the conundrum.

[Met4Cast]

GFS - Very Good

UKMO - Very Good

ECM - Good

GEM - Very Good
Ensembles etc.. also very good. We're now in a very good position. A few days ago we were struggling to find the cold air to tap into and now with each subsequent run, the 850hPas are getting colder. 

I'd say the cold spell is a go after what we've seen this morning. Details still of course to be ironed out, but expect snow events to pop up at short notice, it's quite an unstable airstream. 

[NO LONGER POSTING]

 

Oh GFS ... Can you imagine a time when we might be able to see 300-400 hours in advance and know whats coming, instead FI exists after this time.. . Although I think that would spoil the chase..

[Frosty.]

Comparing like for like, this morning's 00z are an upgrade if you love cold..so I'm happy..hope it continues!

[NO LONGER POSTING]

Also worth mentioning snow amounts over Europe look very good so far... So anything coming from that direction is likely to be very cold 

[bluearmy]

Day 7/8 much flatter upstream on the ec mean than previous runs. Less undercutting of the Atlantic ridge means it's almost flat out west by that point.  (That's the mean upper flow - clusters could be quite different but the mean Atlantic surface high would show a bit further south). 

Edited November 25, 2017 by bluearmy

[Polar Maritime]

The cold trend continues this morning from the models, With the Atlantic continuing to be blocked off..Some of the most interesting model watching for many a year, Woke to a covering of snow here this morning ☺

[mulzy]

4 minutes ago, bluearmy said:

Day 7/8 much flatter upstream on the ec mean than previous runs. Less undercutting of the Atlantic ridge means it's almost flat out west by that point. 

Medium term pain for longer term gain perhaps?  Would be interesting to see if the eps has the retrogression signal similar to the operational.

[Ali1977]

A nice cold week or so nailed but nothing extreme by any means, I'm just wondering if this week is the calm before the storm though - Is a proper big freeze coming 2nd week of December onwards, there's a chance going of today's FI charts - no PV in its usual place that's for sure!!

[joggs]

45 minutes ago, knocker said:

Anyway putting aside the fine detail the ecm is pretty much in the same ball park as the gfs up until the weekend. here it diverges although it does nod in the same direction as the gfs and has energy shooting out of north east North America across Greenland which does flatten (not through though)  the ridge quite quickly and eventually relegating the high pressure to the south west. This allows the Atlantic a route and allows troughs to track east from the north west which could well produce gales in the north whilst returning temps to around normal

This one of the possible scenarios that one could deduce from last night's anomalies

EDIT

I'm wondering why I keep getting different outputs to everyone else. It can only be a conspiracy methinks

 

Mild preference?

[knocker]

1 minute ago, joggs said:

Mild preference?

What the ecm? I'm not sure 'mild' is appropriate terminology at the moment and in any case it smacks of subjectivity which is very much against the ethos of the thread.

[karlos1983]

Another morning where my fear of viewing the overnight runs is replaced with content!! 

Rated purely on next week the big 3 all get a massive tick from me! 

Oh and the uppers are getting colder almost with each run, I don’t think precip falling as rain will be a concern from mid week onward! 

 

 

Edited November 25, 2017 by karlos1983

[Britneyfan]

Great to see models sticking to the cold theme for next week! I feel more upgrades are coming later today 

[northwestsnow]

33 minutes ago, bluearmy said:

Day 7/8 much flatter upstream on the ec mean than previous runs. Less undercutting of the Atlantic ridge means it's almost flat out west by that point.  (That's the mean upper flow - clusters could be quite different but the mean Atlantic surface high would show a bit further south). 

Sounds plausable...just the high in the Atlantic preparing for next phase of retrogression  ...

[Ice Day]

1 hour ago, CreweCold said:

Not bad, not bad ; )

I think the 268 chart would have been 2010esque! 

Another excellent set of runs this morning with a cold/very cold week coming up depending on your location. What's really interesting me is the evolution beyond next week when there remains a possibility of a very significant event. Could go the shape of the pear, but on the other hand.....

Edited November 25, 2017 by Ice Day

[Chesil View]

Nice looking charts again this morning.Although I would urge caution to anyone expecting a 2010 repeat (for now at least). Back then we had a genuine greenland /arctic high building east to Svalbard and south into the Atlantic. What we have this time is an amplified Atlantic ridging extending north. These are two very different creatures.

However there are some retrogression signals in the extended outlooks so one never knows what might occur down the line but for now I do not see the charts showing a Dec 2010 repeat.

Obviously this comes with the caveat that I hope I,m proved wrong over the coming days. Lol