Model Output Discussions 12z 01/09/2016

[Frosty.]

As long as the models keep showing colder than average, I will be happy.

[feb1991blizzard]

Just now, Frosty. said:

As long as the models keep showing colder than average, I will be happy.

Better than mild but I wont be completely satisfied until they show a massive belting right insde the reliable timeframe.

[Frosty.]

1 minute ago, feb1991blizzard said:

Better than mild but I wont be completely satisfied until they show a massive belting right insde the reliable timeframe.

Agreed but the models are showing a cold end to the week which looks nailed on. Baby steps.

[weirpig]

7 minutes ago, feb1991blizzard said:

Better than mild but I wont be completely satisfied until they show a massive belting right insde the reliable timeframe.

There you go   Bound to happen. only at 384h  

Edited October 31, 2016 by weirpig

[jvenge]

15 minutes ago, Polar Maritime said:

Certainly interesting times ahead as even the 'experts' are struggling with very low certainty as we head into wk2. So expect more wild swings in the models over the coming days, with such a turbulent atmosphere atm.

I don't look too deeply for the UK (obvious reasons), but yes, the differences between the GFS 0z and 6z suggests still a lot to play for next week. Past Saturday I'm not sure if there can be much confidence at the moment.

[bradymk]

32 minutes ago, jvenge said:

Just keep in mind that Sea Ice will likely to start an acceleration after November 10th or so and things can freeze fast up there. That said, I'm not sure how much the sea ice will come into play come the start of winter, or if the lack of sea ice now can influence the setup we have in December. Perhaps someone can clarify, but I suspect it would be for a different thread.

Yes the Sea ice will inevitably start to accelerate over the coming weeks but for October it is the lowest it has ever been as of the 27th by some distance. October is a key month for factors such as arctic sea ice and Eurasian snow cover. What happens now, particularly during October can cause feedback loops for the upcoming winter months. 

In regard to how much it will affect the winter, numerous studies have shown Arctic sea ice loss plays an important role in weakening the stratospheric polar vortex. Basically, planetary scale wave generation by sea ice losses and its upward propagation during early winter months can cause a weaker Strat PV and can then cause -ve AO at the surface. Either way, it certainly affects atmospheric circulation and at a record low, we're entering a sort of atmospheric unknown so to speak but it certainly increases chances of -AO/-NAO.

Obviously too, Arctic sea ice represents only one of the possible factors that can affect the polar vortex. Eurasian snow cover, the QBO, El Niño/La Nina and solar activity are just some others, but we're in a good position in terms of sea ice and snow cover. 

Someone else will be able to explain better! But it's certainly a very important factor and it's record low situation this year is a good sign for sure.

Edited October 31, 2016 by bradythemole

[Ali1977]

Quite a lot of talk about split vortex, zonel wind reversal, wave 1 activity on the strat thread. Will the models even show any evidence of this at ground level in FI, or are we likely to see quite sudden flips say 10 days out whilst the models get a handle on these stranger things happening higher up in the atmosphere.  

Surely these factors cause even the METO headaches on longer range predictions, never mind people with my knowledge.

[weirpig]

30 minutes ago, karlos1983 said:

https://twitter.com/judah47/status/793093171144232961

 

It really is very strange  this year    AO predicted to be very negative  for the first 2 3rds  of November  going by that prediction,  Surely that must have some positive ramifications going into the winter season.  If that is correct  i expect November to be below average in temps

Edited October 31, 2016 by weirpig

[karlos1983]

Sorry, it took me a few attempts on how to actually load the tweet rather than a link. 

 

Edited October 31, 2016 by karlos1983

[karlos1983]

14 minutes ago, weirpig said:

It really is very strange  this year    AO predicted to be very negative  for the whole duration of November  going by that prediction,  Surely that must have some positive ramifications going into the winter season

Yes I think so, if you look at everything that is in our favor. We've had the Big strong Scandi High at the beggining of October, the Strat has come under early big time pressure, The Sea Ice extent, Eurasia snow cover which is expanding daily and a stonking -AO prediction, Canada still in Summer, BBQ's out in Greenland (okay so I made that one up) WE ARE IN A GOOD PLACE 

 

(Credit NOAA and Meteociel for images)

Edited October 31, 2016 by karlos1983

[bluearmy]

29 minutes ago, Ali1977 said:

Quite a lot of talk about split vortex, zonel wind reversal, wave 1 activity on the strat thread. Will the models even show any evidence of this at ground level in FI, or are we likely to see quite sudden flips say 10 days out whilst the models get a handle on these stranger things happening higher up in the atmosphere.  

Surely these factors cause even the METO headaches on longer range predictions, never mind people with my knowledge.

The strat thread is looking way beyond events in the trop modelling that we are looking at. Assumptions on what might transpire in Dec and Jan are not going to show on the current fi modelling for a fair while yet. 

The trop patterns are interesting enough for the time of year

be patient! 

And im not too sure where an 'AO very negative' forecast exists for the whole of November??? (That we can see anyway)

Edited October 31, 2016 by bluearmy

[weirpig]

4 minutes ago, bluearmy said:

The strat thread is looking way beyond events in the trop modelling that we are looking at. Assumptions on what might transpire in Dec and Jan are not going to show on the current fi modelling for a fair while yet. 

The trop patterns are interesting enough for the time of year

be patient! 

And im not too sure where an 'AO very negative' forecast exists for the whole of November??? (That we can see anyway)

Ammended  to first 2 thirds  of November.  Surely if that prediction above is anything right  then surely the whole of the month looks like being negative?

[Mucka]

06z was interesting in FI as it suggests a potential slider which others have already alluded to.

 

It may be that the models are beginning to react to the dense cold air that will be over the continent at that time but it could also just be run to run variation.

more runs needed etc.

 

[SMU]

53 minutes ago, weirpig said:

It really is very strange  this year    AO predicted to be very negative  for the first 2 3rds  of November  going by that prediction,  Surely that must have some positive ramifications going into the winter season.  If that is correct  i expect November to be below average in temps

Hi I did a post on TWO that reviewed all the -1 AO Novmebers, back to when the records started- I think Ended up with 9 Novembers so 27 Winter Months -

Of these The return was 21 /27 -AO Months ( included most if not all of the juicy winters )

removing 1998 which was a Super Nino winter the sample went 24/27.... ( 89%)

I will leave that here.....

 

[bluearmy]

1 minute ago, weirpig said:

Ammended  to first 2 thirds  of November.  Surely if that prediction above is anything right  then surely the whole of the month looks like being negative?

Currently predicted to be around the following by mid month re most recent ens

ecm : -2

Geps: -1.5

gefs : -1.6

there doesn't seem to be much appetite for the NH pattern to become positive enough to get those numbers above -1. Even a fairly neutral entire second half of the month would see us around -1 so yes, currently looking like a negative AO month but just how negative is the question. 

[weirpig]

9 minutes ago, Steve Murr said:

Hi I did a post on TWO that reviewed all the -1 AO Novmebers, back to when the records started- I think Ended up with 9 Novembers so 27 Winter Months -

Of these The return was 21 /27 -AO Months ( included most if not all of the juicy winters )

removing 1998 which was a Super Nino winter the sample went 24/27.... ( 89%)

I will leave that here.....

 

Thank you for that information,  9 Novembers however in that period of time  does not  seem like a lot.    I suppose it shows how quite rare the situation we currently find ourselves in.

[Gael_Force]

33 minutes ago, weirpig said:

Ammended  to first 2 thirds  of November.  Surely if that prediction above is anything right  then surely the whole of the month looks like being negative?

It is the CFS so caution but there are some stonking low AO runs in there.

[johnholmes]

16 minutes ago, Steve Murr said:

 

 

But we have to get 'there' first, as we all know, predictions are not always correct but interesting all the same.

[karlos1983]

certainly going to feel different out Sun-Tues going off the 06z GFS.

After the mild weather of late, it will feel cold indeed.

 

[northwestsnow]

Well its going to feel much more like Autumn from tomorrow onwards, gfs12z shows the warmer uppers being shunted south overnight and into tomorrow.

Nice to see a Greenland high in November too, here's to plenty more of that over the coming 12 weeks or so !

[SMU]

A marked improvement of the High pressure over scandi @ 138 on the GFS

138 12z v 144 06z

also a cleaner easterly ... + With a higher pressure over Scandi this will force the CAA further west 

 

perhaps -6s into england on this run....

 

Edited October 31, 2016 by Steve Murr

[swfc]

16 minutes ago, northwestsnow said:

Well its going to feel much more like Autumn from tomorrow onwards, gfs12z shows the warmer uppers being shunted south overnight and into tomorrow.

Nice to see a Greenland high in November too, here's to plenty more of that over the coming 12 weeks or so !

to be honest its not a true greenland high but that aside things dont look to bad do they 

[Ali1977]

8 minutes ago, Steve Murr said:

A marked improvement of the High pressure over scandi @ 138 on the GFS

138 12z v 144 06z

also a cleaner easterly ... + With a higher pressure over Scandi this will force the CAA further west 

 

perhaps -6s into england on this run....

 

Quite a big difference in NE canada too, the low on the 06z has gone - not sure how that will effect us but may help build some heights/WAA into Greeny again.  Looks cold on Sunday, wintery showers in England on the hills with those temps.

 

Edited October 31, 2016 by Ali1977

[SMU]

Very very good afternoon so far

GFS good to about 162- you can it trying to drop energy south - however after that the GFS rolls all the energy eastward

UKMO - superb with the 524 line in the NE at 144 indicating a high chance of snow falling !!

[Captain Shortwave]

GFS and UKMO at day 6

   

A fairly deep trough aligned SW/NE through western Europe with a raw north easterly wind, this will need watching as an airmass which would be cold enough for snow even at low levels is not that far away. Whilst the models seem to be bringing westerlies back in in week 2, we must watch for potential other solutions to develop. We do have weak heights over north Scandinavia which could very well have greater influence than what is being suggested now. By Sunday maximum temperatures look to be 6-8C at best, possibly colder still if we can get a cleaner feed of cold air from the east/north east.

Food for thought considering that the 20C mark was breached quite widely in parts of England and Wales today.

 

Edited October 31, 2016 by Captain Shortwave