Model output discussion - winter proper underway

[gottolovethisweather]

Well, the mild blip referenced here, seemingly turned out to be a forecast for an extended period of milder than average Temperatures. ust goes to show, we can predict stuff all we like at a surface-level, but the primary drivers of the bigger picture are often detected far sooner by the pros. My local UKMO forecast now predicts a gloomy ole picture for Newbury, scraping double-digit every day with leaden skies right through to Christmas Day itself with no crisp frosts under clear skies, yuk! Here's hoping even that forecast might alter to allow for some brighter skies. It's enough to put me off chasing FI charts for a few days, so into lurk mode I go.

Meanwhile, post-Christmas Day and beyond, hints of a-change are undoubtedly worth contemplating if you ask me. The Pacific ridging and the resultant Arctic warming must surely mean a change of direction, but the question is how will our little island be affected by it all? This latter aspect has been predicted in mid-range across all the model suites of late as shown below. Will it mean a ramping of the Jet, I wonder? I guess so, and in time it should dig south too. This post from Singularity sums things up very nicely if anybody hasn't seen it as well.

 

This was Sunday evening's ECM 12z at t+144.

 

Here's the NH image for the same timeframe now, courtesy of the ECM 0z.

That's a retrogressing High near us, and low heights over the near continent. 

The t+144 hours offering ie. Christmas Day offering is interesting for sure, when looking at NH setup. Euro heights are building, granted but a change is a-foot over our shores. Focus on the encircled red area and the black boxed area.

And here's the Boxing Day offering, again a decent enough offering given the run-up to the festive period. Again, focus on the black and red paint jobs, highlighting regions to focus one's attention on over the coming days.

 

I cannot be drawn into looking beyond D5 regarding the surface specifics because I am of the opinion, a pattern-change is obviously on its way, but whether it brings the holy grail of wintry weather to one and all, the jury is very much still out on that one.

Do have a great festive break guys n gals and enjoy it, but equally stay safe, fit and well. 

 

Edited December 19, 2017 by gottolovethisweather

[Dennis]

the change.... ?? Ridge at NE USA

[Devonshire]

5 hours ago, BLAST FROM THE PAST said:

am very keen on this Xmas period, in the winter hopes thread on 7th Dec I mentioned anticipated strong solar wind hit around 22nd.  Well today we have Earth facing Coronal hole with strong solar winds anticipated to arrive 21/22nd bang on cue (info courtesy of space weather).  Let’s see what develops from here.  My thoughts on this are jetstream effects (meandering more/ southward shift) and increase in depth/strength of LPs.

I am not sure where you are getting a 'strong solar wind' hit from - there are 2 small coronal holes on Earth side of Sun - certainly nothing out of the ordinary to my eyes, especially in light of much larger ones that trundle round periodically (days, not weeks). I will keep an eye on the jet though in case it exhibits any extraordinary short-notice behaviour - same with LPs, though my (limited!) understanding is that flares/CMEs are more implicated than solar wind in affecting strength/track of storm systems.

To appease mods: if there is a sudden effect on the Jet I guess we can look at sudden (actual) departures from modelled jet track /LPs in very short term - as well as any sudden large shifts in models' track of jet/LPs, wrt timing of solar wind inpacts .... maybe. It would be great to think that Solar teleconnections could be included in (public) models - or at least included (mechanistically) by those who are switched on to teleconnections. I suspect this conversation is for another place though ...

Edited December 19, 2017 by Devonshire
typo

[BlueHedgehog074]

Not sure if it’s just me, or that the ECMWF maybe has a habit of making Low Pressure systems a little too cut off/separate at times in FI! 

The chart at 192 hours from the 00Z run being an example.

I know ECMWF can have a possible habit of over-doing amplification of the weather patterns at times, but I think I remember seeing similar charts like the above where the ECMWF had a habit of having too much separation between the Lows, particularly the stormy ones. The results being Lows that would end up being less separate and more organised.

[Seasonality]

I think the 12z is going to pull some interest out of the hat as of the 27th of December. Colder air back over the UK, with -8 850s creeping towards northern Scotland. Sorry, can't post images at the moment.

 

[frosty ground]

1 minute ago, Seasonality said:

I think the 12z is going to pull some interest out of the hat as of the 27th of December. Colder air back over the UK, with -8 850s creeping towards northern Scotland. Sorry, can't post images at the moment.

 

[feb1991blizzard]

GFS 12z is about to bring a dumping for somewhere in the UK, not sure I buy into its earlier evolution though, doesn't match the UKMO wrt the alskan / pacific ridge.

Edited December 19, 2017 by feb1991blizzard

[Ali1977]

impressive ridge, you'd think things could get interesting beyond this if the models only went to 192. If only an Atlantic burst of WAA could meet it 

Edited December 19, 2017 by Ali1977

[Seasonality]

Chalk and cheese. Much better run if colder weather is what you're after.

[tight isobar]

Geting going!!!

Things on a' momentum phase as the pac ridge starts to arrange with other incline-to exact- a colder outlook for uk.

850s are now produce of the the evolutions of modeling ...they always look undercooked when there is a pattern change to hand...

And mid term...you can decipher that colder infer-into the mix via pm flow and things taking a transition!!!

Edited December 19, 2017 by tight isobar

[Singularity]

Well, it all got a bit messy across N. America and I was thinking what a shame that was, but now GFS has gone and decided that a very strong poleward push of heights is on the menu after all.

Pretty cool idea I guess 

 - but I still prefer the stronger first attempt that UKMO 00z/12z and ECM 00z depict 

[Daniel*]

GFS 12z is pretty wintry for a time following ECM 00z of this morning a more positive day for coldies. 

[Seasonality]

And there were some writing off Xmas week and even further ahead. Just goes to show, even at the 6 and 7 day juncture it is still wide open. Will await the ECM 12z with renewed interest!

[ACCOUNT DELETED]

What about that Boxing Day storm? Is that still showing on the GFS 12z? I can't look at the charts atm 

[feb1991blizzard]

2 minutes ago, Seasonality said:

And there were some writing off Xmas week and even further ahead. Just goes to show, even at the 6 and 7 day juncture it is still wide open. Will await the ECM 12z with renewed interest!

Wide open for what though? - yes a brief cold snap but look through the ensembles, is anything sustained likely?, I'm still and always have been writing xmas week off for any potent outbreak and probably a decent way beyond that right now.

[knocker]

The gfs still has the wave 'bombing' but tracking a little further to the north west with a strong low level jet.

[gottolovethisweather]

24 minutes ago, Seasonality said:

And there were some writing off Xmas week and even further ahead. Just goes to show, even at the 6 and 7 day juncture it is still wide open. Will await the ECM 12z with renewed interest!

Note, the "some" in the above.  To be fair, I think it's the locked-in cold Synoptics so many want, they were quick to write off, but such spells can creep up on us out of the blue. Transient snow is the way of things these days and expecting bitter cold for days on end is a most unlikely scenario, we're given what we're given in the UK due to our position in the globe and we need to be realistic. Getting back to the specifics, the sum of it being, we should never judge a single model run in isolation, we should compare like with like, 12z with 12z or 0z with 0z and look at the bigger picture, despite that being an old netweather JH (and several trusted other nw folks) proverb, it holds a lot of water, at least the skies shouldn't for a while. Anyway, I'm supposed to be lurking, mid-range improvements, good stuff, keep em coming! 

Edited December 19, 2017 by gottolovethisweather

[SMU]

A decent ish UKMO @144 keeps the dream alive possibly for NI & North western areas for Xmas day !

The high across the pole is worth watching at this stage as well as it’s exact location is hard to model....

S

 

[The Eagle]

The big freeze across North America by day 9 has all but disappeared...

 

 

See, it does not only happen to us!

Edited December 19, 2017 by The Eagle

[Dennis]

3 minutes ago, The Eagle said:

The big freeze across North America by day 9 has all but disappeared...

 

 

See, it does not only happen to us!

True it can quick change ; and some have mentioned about that - Europe could be hit soon agan

[Paul_1978]

17 minutes ago, The Eagle said:

The big freeze across North America by day 9 has all but disappeared...

 

 

See, it does not only happen to us!

Which, if it verifies, means a weaker jet stream perhaps.....

[fromey]

18 minutes ago, The Eagle said:

The big freeze across North America by day 9 has all but disappeared...

 

 

See, it does not only happen to us!

Surely that could be good for us, slow down the jet stream etc? 

[swebby]

18 minutes ago, The Eagle said:

The big freeze across North America by day 9 has all but disappeared...

 

 

See, it does not only happen to us!

Ah, but did it end up in Greece instead?

Over the past few days the GFS and ECM have been churning out some pretty extreme solutions in the extended period (<950mb alantic lows, big alaskan ridges, on/offf pacific typhoons, scandi highs).  How much faith we should be putting in the extended outputs, including the ens, at the mo is debatable. 

[nick sussex]

Yesterdays GFS 12hrs run to T216 hrs versus todays to T192hrs:

 

Todays:

 

A good reason to not be looking too far ahead and also a good reason to ignore the ensembles until the models settle down. Its obvious theres lots of background noise.

As we saw from this mornings ECM op run versus yesterdays.

So far today its been positive in terms of shortening any milder mush and the impossible a few days back might seem less outlandish today.

Theres still a chance Christmas week could develop more wintry potential.

 

 

[Boro Snow]

1 hour ago, The Eagle said:

The big freeze across North America by day 9 has all but disappeared...

 

 

See, it does not only happen to us!

But it quickly returns and is there throughout the rest of the run on the GFS 

Edited December 19, 2017 by Boro Snow