Model output discussion - Winter has arrived and the hunt for cold is on

[SMU]

40 minutes ago, jordan smith said:

Are you okay Arpege?

Seems to want to bring heavy rain into southern counties and have it eventually fall as heavy wet snow during Tuesday.. No other model aggreement though so atm very small chance.

Gem agrees on rain pushing in but remaining as rain.  putting any other detail onto that at this stage is rather pointless but will be interesting to see what the afternoon and evening runs bring and if there begins to be more support or.. None. We shall see. 

Me & @shaky talked about this the other day when GEM showed it

ECM is broadly the same @T84

Its where the system moving up from biscay bumps into the relative cold air streaming SW over England.

 

Much stronger ridging from the GFS 06z

Not quite this run though - Deep cold edging further SW though-

 

 

[shaky]

8 minutes ago, Steve Murr said:

Me & @shaky talked about this the other day when GEM showed it

ECM is broadly the same @T84

Its where the system moving up from biscay bumps into the relative cold air streaming SW over England.

 

Much stronger ridging from the GFS 06z

Not quite this run though - Deep cold edging further SW though-

 

 

Yes we did steve and its a realistic possibility now!!something to keep an eye on and for.once its not in fantasy island!!better ridging into scandi at 168 hours on gfs!!!keep the upgrades coming!!

[Methuselah]

I think I must be seeing a different set of charts, to everyone else!

    

[Skullzrulerz]

27 minutes ago, Steve Murr said:

Me & @shaky talked about this the other day when GEM showed it

ECM is broadly the same @T84

Its where the system moving up from biscay bumps into the relative cold air streaming SW over England.

 

Much stronger ridging from the GFS 06z

Not quite this run though - Deep cold edging further SW though-

 

 

Can I ask what date this is showing on the GFS 06z? 

Seems there may be some surprises on the way to Xmas before becoming milder just before the big day 

 

[Jordan S]

33 minutes ago, Steve Murr said:

Me & @shaky talked about this the other day when GEM showed it

ECM is broadly the same @T84

Its where the system moving up from biscay bumps into the relative cold air streaming SW over England. 

Yes the Ecm does show it but low confidence on this and it could remain mostly to our southeast just grazing the southeast with Rain. Such as the Icon and Gfs show. 

GFS. 

Icon. 

Edited December 14, 2019 by jordan smith

[SMU]

20 minutes ago, Skullzrulerz said:

Can I ask what date this is showing on the GFS 06z? 

Seems there may be some surprises on the way to Xmas before becoming milder just before the big day 

 

Day 7 168..

[IDO]

It looks like a benign rather bland end to December, mostly average temps wise. There was an opportunity for cold in around a week but with no forcing, any promise just evaporates as the NH profile zonal flow takes hold. All models going to D10 suggest this at the moment.

We see the FI on the 06z^^^. Not a lot further to say really apart that the tPV is still not a driver per se so as we head into January getting cold to mid-lats will be quick, just can we see the underlying state allow the UK to get in the action?

[Jonathan Rhodri Roberts]

Well the GFS isn't feeling very festive this morning with the low teens making a comeback all thanks to a long fetch of southerly winds for Christmas Eve's Eve

[SMU]

More GFS ensembles starting to warm up  All around day 7. 

 

 

[booferking]

4 minutes ago, Steve Murr said:

More GFS ensembles starting to warm up  All around day 7. 

 

 

I hear yea brother.

[IDO]

Hard to spin it any other way, the GEFS T850 mean in FI...

...is not great. The tPV trending to its natural Winter home, but just one run and expected when the NH profile flattens.

[Nick F]

1 hour ago, Steve Murr said:

Me & @shaky talked about this the other day when GEM showed it

ECM is broadly the same @T84

Its where the system moving up from biscay bumps into the relative cold air streaming SW over England.

 

Closer-up charts of 00z EC for noon Monday, you would never guess snow possible with those 850mb temps

Edited December 14, 2019 by Nick F

[Ali1977]

Mean starting to show the height rise to our NE.

[swfc]

6 minutes ago, IDO said:

Hard to spin it any other way, the GEFS T850 mean in FI...

...is not great. The tPV trending to its natural Winter home, but just one run and expected when the NH profile flattens.

youd be surprised about the spin.Anyway yes unless theres a big turn around midterm looks an unsettled spell on the run up  to new year.nothing unusual for december

 

 

 

 

 

 

[SMU]

5 minutes ago, Nick F said:

Closer-up charts of 00z EC for noon Monday, you would never guess snow possible with those 850mb temps

Classic Evaporational cooling with decent lapse rates !

[Mapantz]

UKV is having none of it:

 

[Jason M]

16 minutes ago, IDO said:

Hard to spin it any other way, the GEFS T850 mean in FI...

...is not great. The tPV trending to its natural Winter home, but just one run and expected when the NH profile flattens.

First post of the winter because I've seen nothing to interest me cold wise (and still don't!). That said, this obsession with mean charts 10 days or more away is surely not healthy as they will nearly always show climatic norms (albeit I think you know this ).

 

 

 

[SMU]

2 minutes ago, Jason M said:

First post of the winter because I've seen nothing to interest me cold wise (and still don't!). That said, this obsession with mean charts 10 days or more away is surely not healthy as they will nearly always show climatic norms (albeit I think you know this ).

 

 

 

Yep totally pointless waste of energy unless there is a considerable signal for a Greenland high an isolated mean at day 10   will never provide anything meaningful - especially when you are looking at small wedges of high pressure to steer the jet stream.

[Jason M]

2 minutes ago, Steve Murr said:

Yep totally pointless waste of energy unless there is a considerable signal for a Greenland high an isolated mean at day 10   will never provide anything meaningful - especially when you are looking at small wedges of high pressure to steer the jet stream.

I'd argue the same even if he were showing a Greeny high. I've seen many examples of these beasts out in FI but they are rarer than hens teeth in reality.

[MP-R]

Keep having to remind myself it's December looking at the output. This chart below almost looks like a poor summer chart for the UK. Add 5C to the 850hpa's and it could be July - heat building over Spain.

The extent of warmth moving up over inland Europe as well is quite notable for the time of year. Is it conceivable that the increasingly weak Atlantic as time goes on is actually hindering any pattern change as conditions become flabby in situ and troughs become unstuck? 

[I remember Atlantic 252]

58 minutes ago, Nick F said:

Closer-up charts of 00z EC for noon Monday, you would never guess snow possible with those 850mb temps

Tues, but rather the UKV came off posted by Mapantz below, FAX also seems to agree with UKV

[IDO]

57 minutes ago, Jason M said:

First post of the winter because I've seen nothing to interest me cold wise (and still don't!). That said, this obsession with mean charts 10 days or more away is surely not healthy as they will nearly always show climatic norms (albeit I think you know this ).

 

 

 

...they show trends with flow if you are reasonable sure of the long-wave pattern. The charts show quite a smooth transition of the tPV moving towards the NW of the UK (why I did a GIFF), that has not been seen much this season. The upper temps show a lack of cold reflected in the vast majority of GEFS. 

I would say that the mean has a higher verification than the op at the same range and a significant better representation than random ensemble members that are posted Just For Fun?

53 minutes ago, Steve Murr said:

Yep totally pointless waste of energy unless there is a considerable signal for a Greenland high an isolated mean at day 10   will never provide anything meaningful - especially when you are looking at small wedges of high pressure to steer the jet stream.

...the charts I posted were post when the wedges are being consumed by the lower heights. Based on current modelling and accepting the usual caveats and disclaimers with the weather.

Edited December 14, 2019 by DiagonalRedLine

[Nick F]

8 minutes ago, I remember Atlantic 252 said:

Tues, but rather the UKV came off posted by Mapantz below, FAX also seems to agree with UKV

Yeah, apologies, is Tuesday not Monday!

[Dennis]

Icon6z 

[Catacol]

2 hours ago, Steve Murr said:

More GFS ensembles starting to warm up  All around day 7. 

 

 

Worth chipping in here and saying anecdotally that the GFS ensemble suite may be doing rather well against EPS according to US observers. For once it would appear that the EC is having a problem picking the Pacific pattern, and verification stats for Dec might be worth a look at month’s end. While we know GFS has a westerly bias in the Atlantic if it is doing a better job of sorting out the MJO conundrum in the face of static conditions in the IO then it has a head start. Might be a time not to be so quick to bin GFS and hence the charts above have cogency.

Some kind of change is coming. The Pacific signal is tougher than usual to read right now, and GLAAM is heading downwards at the moment which is not good (though was expected) but the passage of convection towards the maritimes will undoubtedly inject some kind of extra westerly momentum to shake up the relatively flat pattern of the last 10-14 days or so. NWP is making a right mess of working out exactly where any heights might land, but with a long range eye to things I’m hoping it will be as close to Scandy as possible in order to encourage the strongest available wave 2 forcing on the vortex. A cut off high with an easterly feed would be the pot of gold at the end of a rather long shot rainbow given the current wider context, and a more static and settled end product with frost overnight but not a great deal in the way of lowland snow potential feels the more likely best end product for the Xmas period. Worst case scenario would be insufficient forcing to get Euro heights northwards, and the dreaded spectre of a long draw southerly as heights get only half way there. Yuck...but not the form horse in my view.

No harm eyeballing the pot of gold, and hoping MJO progression might emerge robustly, giving a spiking westerly momentum profile that could support a genuine high lat block. We are certainly in the business end of winter now with sufficient cold air across the NH to give proper wintry conditions given the right synoptics.