Model output discussion - 5th December 2016 - Into Winter we go

[Abyss]

59 minutes ago, feb1991blizzard said:

Glosea for me - its modelling of the strat is second to none and been faultless for a few years since its inception. mild to very mild winter overall for me.

Didn't Glosea indicate a cold loaded first half to Winter?

Edited December 11, 2016 by Abyss

[Mucka]

16 minutes ago, Nick F said:

With the potential for the trop PV retreating west over Canada because of the +EPO / break down of Aleutian high I mentioned in my last post, certainly feasible for a high to the west as per 18z GFS FI, though equally the high may ridge north over or east of the UK, depending how the wavelengths adjust.

Everything is feasible two weeks out including Santa riding in on an Easterly, I'm just of the opinion the only aid blocking to our East will be is to help back up the Atlantic enough to get a little amplification upstream.

That could be a bad call but I just don't see an Easterly with a Scandi/Russian block even with a fairly favourable turnaround upstream, in that instance I would expect the high to retrogress NW with only a brief Se/E/NE flow as it attempted to retrogress either ending in a failed attempt and UK high or better attempt and trough dropping through Scandi which would be the opposite of Scandi high/Easterly scenario.

The undercut necessary does not seem possible but a negatively tilted trough and retrogressing high seems more plausible - I just don't favour as I think the the Atlantic pattern will be too fast and flat meaning high pressure will likely be further East and accordingly the trough and by way of logic any amplification upstream would be Atlantic sector in such a scenario.

I will admit the current anomalies don't suggest any of this, they are just the possibilities I see in my minds eye having watched the output slowly evolve toward a new pattern somewhere around Christmas.

Not often I stick my neck out but someone has to be the Xmas pudding.

 

 

Edited December 11, 2016 by Mucka

[Nick F]

35 minutes ago, nick sussex said:

BA the JMA later output ties in with your earlier post re the Siberian high giving the Euro high a helping hand nw and troughing digging se.

Desperate times when we start wheeling out the JMA, though I suppose that model has more cred than NOGAPS. 

The short to medium range we will just have to make the most out of the potential for increasingly colder/drier surface air arriving from near continent late week and next weekend as still advertised by 18z GFS, with return of frosty nights. But there are increasing signs we may see sufficient changes in the upper flow around Xmas to perhaps bring something more interesting ...

Edited December 11, 2016 by Nick F

[nick sussex]

6 minutes ago, Nick F said:

Desperate times when we start wheeling out the JMA, though I suppose that model has more cred than NOGAPS.

The short to medium range we will just have to make the most out of the potential for increasingly colder/drier surface air arriving from near continent late week and next weekend as still advertised by 18z GFS, with return of frosty nights. But there are increasing signs we may see sufficient changes in the upper flow around Xmas to perhaps bring something more interesting ...

Lol! Yes and I think the current situation does qualify as desperate times! The last few weeks of tedium would be forgotten if we could somehow get something interesting over Christmas.

[snowray]

2 hours ago, Weathervane said:

That would be a great call. One of my favourites from the archives is December 1938 when a high migrates from  around Nova Zemyla to Scandinavia over a week or so. Unforeseen then and I wonder how well it would have been forecasted today?

Oh what I would give for a chart like that on 20th Dec....

 

But GFS 18z London ENS are having none of it, Yuk!

[Cheshire Freeze]

2 hours ago, fergieweather said:

Incidentally, after such a prolonged period of close broadscale agreement between runs of GloSea5 and ECMWF Seasonal, you'll note now how they finally bid each other farewell in their respective Dec updates and ride their own separate ways into J-F-M. Glosea fits with previous thinking (a marked switch away from -ve NAO 2nd half of winter); ECMWF continues similar to before. Of course, the combined 3-monthly means mask detail of how the journey unfolds, but it'll be intriguing to watch.

''a marked switch away from -ve NAO 2nd half of winter''

Well to see a switch away from a -NAO we'd have to have the -NAO first 

Not a chance this month will return a mean -NAO

[Seasonality]

Positives from the 00z. The euroslug is on the move again at the end of the run. Seems to be a growing trend. 18z parallel for comparison.

 

[AWD]

If that T384 GFS 0z Op chart is the best the GFS has to offer this morning then I think I'll go back to sleep for another 2 weeks.

[Mucka]

10 minutes ago, Seasonality said:

Positives from the 00z. The euroslug is on the move again at the end of the run. Seems to be a growing trend. 18z parallel for comparison.

 

We have seen the retrogressing high scenario played out many times already in FI over the last few weeks but it has never made it inside day10.

We can but hope.

Edited December 12, 2016 by Mucka

[BLAST FROM THE PAST]

The only thing on my mind here is 'drought'.  ah well at least my pre Xmas visits to Wales will not be affected by the weather 

 

BFTP

[knocker]

Today

Cool with fog in some central southern areas but clearing fairly quickly. Sporadic light rain, already into the south west, will track north east during the day. Becoming drier over night but the next frontal systems soon arriving late Tuesday/early Wednesday.Remaining quite mild today particularly in parts of the south west.

Yesterday evening the were indications of a change in the long wave patter upstream in the latter stages of the run which could well influence proceedings downstream with the tough in the NW Atlantic becoming less influential but how that effect the evolution in the eastern isn't yet clear, well to me anyway. So as usual just sticking to the next ten days where the pattern has as yet not changed hugely so it remains the day to day interaction between the energy emitted upstream and the Azores ridging which just needs sorting.

 

As mentioned above the next frontal systems arrive Wednesday morning but the upper trough deconstructs against the ridge so quickly on to a repeat on Friday

From here until day ten the HP sets it's stall out to the east/south east replenished by the Azores feeder whilst the trough(s) run east/north east on the strong thermal gradient that this interaction produces.

By day ten the large, complex, trough to the north has has depressed the high pressure somewhat thus allowing systems to track further south and and impact the top half of the country.

A quick synopsis of the weather. With high pressure being in mainly in charge the period will be quite dry, especially so in the south east. with just some sporadic rain in the west. The exception being Scotland which may well cop some fronts as systems track further south. Temps generally around average.

The GEFS anomalies this morning confirm the pattern change and the decline of the Atlantic trough but no indication of height rises to the east, more a return to zonality

Edited December 12, 2016 by knocker

[Weather-history]

6 hours ago, Nick F said:

Desperate times when we start wheeling out the JMA, though I suppose that model has more cred than NOGAPS. 

The short to medium range we will just have to make the most out of the potential for increasingly colder/drier surface air arriving from near continent late week and next weekend as still advertised by 18z GFS, with return of frosty nights. But there are increasing signs we may see sufficient changes in the upper flow around Xmas to perhaps bring something more interesting ...

My memory maybe failing here but I'm sure some reputable person in the past said JMA model is regarded by the Met Office. This raised some surprise. 

[northwestsnow]

ECM-day10....wet.and..windy..christmas..incoming?

[igloo]

9 minutes ago, northwestsnow said:

ECM-day10....wet.and..windy..christmas..incoming?

it would be a welcome site for some after near drought conditions for the past 2 months but dont underestimate the euro slug its hanging on for dear life

Edited December 12, 2016 by igloo

[Nick F]

48 minutes ago, Weather-history said:

My memory maybe failing here but I'm sure some reputable person in the past said JMA model is regarded by the Met Office. This raised some surprise. 

I think they are well-regarded for tropical forecasting

7 minutes ago, northwestsnow said:

ECM-day10....wet.and..windy..christmas..incoming?

Thank goodness it's day 10! Though all models seem to be singing from the same hymn sheet this morning. Still think we may see changes to the wavelengths around Xmas due to tropical forcing / changes over the NE Pacific.

[northwestsnow]

9 minutes ago, Nick F said:

I think they are well-regarded for tropical forecasting

Thank goodness it's day 10! Though all models seem to be singing from the same hymn sheet this morning. Still think we may see changes to the wavelengths around Xmas due to tropical forcing / changes over the NE Pacific.

Hopeso.Nick...'winter'..fast..turning..into,,another.horror.show..

WAA..into..the...arctic?uppers..+5.into..the..Barents.sea.

Edited December 12, 2016 by northwestsnow

[knocker]

The ecm is not dissimilar to the GFS up to around T180 when the vortex and the trough make their move. This latter period is still to be resolved.

Edited December 12, 2016 by knocker

[Les Penniston]

1 hour ago, BLAST FROM THE PAST said:

The only thing on my mind here is 'drought'.  ah well at least my pre Xmas visits to Wales will not be affected by the weather 

 

BFTP

Thinking exactly the same BFTP not much change in the models at the moment

 

[bluearmy]

Interesting feature headed into the Atlantic day 10 on ec op. The cold high started its life as part of the Siberian vortex ridge (its there at T0) . not sure we have seen one of these work its way around the NH, given the fairly neutral/neg AO that has been persistent thus far. 

If it were to verify, it might be an interesting  addition to the equation .

[West is Best]

Pretty grim models for those of us wanting something more seasonal. All 3 big players continue the Atlantic drift out into the medium timeframe. Sigh. Thankfully it's still only 12th Dec.

[fergieweather]

6 hours ago, CreweCold said:

''a marked switch away from -ve NAO 2nd half of winter''

Well to see a switch away from a -NAO we'd have to have the -NAO first 

Not a chance this month will return a mean -NAO

Ha ha. I was, of course, referring to the *model output* and where it sat previously versus now.

Talking of which: yesterday's Glosea run has suddenly retreated from the stronger zonal/mobile theme into early Jan and is much less bullish now: more blocked members again therein. If today's run does likewise, anticipate some tweaking to wording of UKMO 15-30d outlook, albeit they note ECMWF tonight awaited for comparison anyway.

[KTtom]

Heights dominating to the south and east but nothing in the way of cold, by that I mean in the way of sub minus 5 uppers, being forecast for the uk. Whilst we continue to dream about an '87 or '91 I feel winter will slowly ebb away and we'll remain in nomans land. Hopefully the Vortex will move from the north west to the north east sooner rather than later, probably have to wait until new year for that though, then we may have a better chance of something more interesting 

Edited December 12, 2016 by KTtom

[karlos1983]

Well that's a good update for a Monday morning. No way way was I expecting that. Thought it would be the EC flipping back. Look forward to updates tonight/ tomorrow 

[Dennis]

Last 10 days of this month could have a quick change .....

[snowsummer]

Firstly sorry mods if this is wrong thread (strat thread maybe?) but do the models take into account the effects of space weather?  I only ask as where this thread has been quieter of late, I've been attempting to understand the connections between solar winds,polar stratospheric  clouds sunspot numbers etc and the effects on our weather (or more importantly our winters!) could someone please point me in the right direction to learn more? thank you