Winter Season: Forecast and Model Discussion Commentary

[Lukesluckybunch]

8 minutes ago, That ECM said:

Lukesluckybunch here’s the problem imo. It’s going over the top.

Yea..-8/10 uppers creeping in from the east,but for how long..looks short lived to me

[That ECM]

 Lukesluckybunch  tbh it did better than I thought.

[TSNWK]

Yes it is going to topple over us.. but blooming hell I think we would all back 06z for now up to date 10 and then work with the latter stages in subsequent runs.

Edited December 14, 2024 by TSNWK

[northwestsnow]

6z  is great for a cold Christmas.. 

In the words of Victor Meldrew.....

[Ruzzi]

 northwestsnow

And also @LRD .... he doesn't believe it either  

 

Just a joke

[northwestsnow]

 Ruzzi

I want to believe

Mean has nudged towards the op TBH..

6z v 0z 168

[I remember Atlantic 252]

GFS still going with 'Eowyn' though

[Johnp]

Looks like the control going a similar route too. 

[Legend.Ice]

If compare JMA and GFS, there are serious differences in terms of the strength of the cold, especially Skandi and the Greenland region, JMA reads incredibly differently for such a close term

[TSNWK]

 Johnp told by those more knowledgeable that is a very good thing to see….

[Met4Cast]

47 minutes ago, bluearmy said:

my point is that I think the MJO analogues currently show part of a range of possibilities. when on a predictable high amp circuit they’re useful as a tool to illustrate where the nwp should/could be but given the lack of consistency/certainty on both MJO forecast and enso state I’m not sure they’re very useful atm. 

Agreed & a perfect example of why/how taking the MJO in isolation often leads to disappointing outcomes when blocking doesn’t deliver. 

I’m not sure what composites we’re supposed to be viewing, as you say atmospherically things look more Nino, but ocean wise it’s Nina, certainly a disconnect there and a lack of “coupling” which is quickly becoming the buzzword! 

This disconnect is largely driven by the strong westerly wind bursts in the Indian Ocean which up until now has been driving the +AAM tendency and associated Nino-esq atmospheric signature. 

Looking ahead though these WWB’s are due to fade as the MJO progresses east, coupled with strong Nina trade winds in the Pacific it does seem a trend towards ocean/atmospheric coupling and a return to -AAM is on the cards into the new year. 

Not ideal for those of us chasing cold that’s for sure! 

But to go back to MJO composites.. no idea agreed that they might not be overly helpful in the current situation. 

[Fog bound]

 blizzard81 that sounds like a spell… this would be a nice development though! Shows up the variability between runs!

[Met4Cast]

Just to add to the above - 

-EAMT (red line) and overall -MT has allowed overall GLAAM to fall back negative despite on-going +FT, I do expect we’ll see a return to +ve AAM as the MJO progresses and MT turns positive but to what extent remains uncertain. 

In any case - The period of opportunity remains 17th-28th, now obviously looking later into that period as by January teleconnective forcing will become unfavourable for high latitude blocking. The strengthening tPV really is a pain in the bottom to any potential high latitude blocking, despite increasingly favourable MJO phasing.. 

Tricky. 

[WYorksWeather]

ECM meteograms below for Reading and Aberdeen, off the 00z.

Reading first - not much sign of a cold snap here. Temperatures pretty much always above average on the mean, especially so by night (daytime temperatures may be suppressed by cloud amounts at times). Wind directions are mainly westerly, and a lot of cloud around.

For Aberdeen it's largely the same, though there is slightly more evidence of a cool down around 20th-23rd. It's not really a cold snap though - similar to Reading, the overnight lows never drop below average, and daytime highs only drop to around or just below average.

All in all, we are still looking at a very westerly pattern, with perhaps occasional north-westerly interludes bringing slightly cooler conditions. Christmas to New Year period is still outside the reliable and not to be written off yet, but unless there's a major change in the closing days, it will be another very mild December.

 

[That ECM]

Gefs T280 ish scandi height possibilities? 
 

might be hope casting on my part.

[blizzard81]

 BarometerCat Variability, volatility....all the V words. Much to be resolved yet in the days preceding Christmas, let alone Christmas itself.

[swfc-ocs]

Gfs 6z control if not especially wintry but heading in a dry and seasonal direction.All in fi but a large portion  of pv is also on its bike nne

[johncam]

 Lukesluckybunch every winter is a struggle now .

[SollyOlly]

 johncam Yes, definitely feels that way. Dec is shaping up 'as usual' so far...I can just see these chases being hinted at for weeks on end, failing to deliver, and then all of a sudden it's Spring again. You'd think that we'd be used to it by now...(!).

At least today is ok, locally. Decent bit of sunshine and not too mild. That'll do, when beggars can't be choosers...!

[phil nw.]

 Met4Cast

I think we are at a bit of a crossroads wrt to January's prospects now.

I believe we are currently seeing the lag effect of the mjo in the warm phases 4/5  and it has become slow moving.

Therein lies the problem for future prospects I think. Will we see the movement east eventually into 6/7 and the increase in momentum again.

This is the pathway to some weakening of the tpv later and increasing chances of blocking at higher latitudes.

The mjo forecasts are still variable on this with Ecm less good.

We wait and see how this develops in the coming days.

[northwestsnow]

 phil nw.

Yes Phil today's GEFS is very good ,high amplitude 6/7

EC less so

divergence starts today

Edited December 14, 2024 by northwestsnow

[phil nw.]

 northwestsnow

Yes if only....

[TSNWK]

 northwestsnow would that mjo then be part of reason for jet to head south east into Europe?

[blizzard81]

 northwestsnow Ha ha. Huge spread on the latest mogreps from 21st Dec.

[northwestsnow]

 TSNWK think it's a bit more complex than that but if you are of a cold persuasion high amplitude phase 6/7/8 is what you want.

Edited December 14, 2024 by northwestsnow