Winter Approaching: Forecast and Model Discussion Commentary

[swfc-ocs]

Pretty rank 6z gfs tbh.will it vaify / hope not.Im not sure when the mjo uptick will show its head but hopefully some better runs and charts inbound

[StretfordEnd1996]

 swfc Yes not the best in the D7-10 range, pretty awful with that flat W/SW pattern

Still time for a bit of eye candy in deeper FI, got to start somewhere I guess! 

[TSNWK]

Normal services..can't even get eye candy fi  presently 

Edited December 6, 2024 by TSNWK

[AO-]

 swfc

If there is cross model agreement together with consistency, this is unfortunately the direction of travel. Too early to tell still. Again the shortwave is blown up early with the zonal pattern as a result. Similarities with EC00

[TEITS]

I have no confidence in the models at the moment especially with regards to the low pressure S of Greenland at +120. Even less confidence beyond and in my opinion makes the ensembles pointless.

I'm not making any predictions or saying a sudden flip to cold will occur. However at times you can see a significant change in the model output at a relatively early timeframe with the ensembles only slowly following behind. I feel we could well see this around the +120 period onwards.

[bluearmy]

Interesting to see that this flatter hemispheric run (in the mid term) has a lesser warming in the upper strat 

still notable but not on the same level as the 00z run 

it has bothered me that with the trop patterns dictating, we are reliant on trop modelling verifying to see sig warming high up 

[damianslaw]

Too much chopping and changing from the models at the outer edges of the reliable to give any faith in them at present. One of those occasions as always best sticking to the reliable which is about 11 Dec tops at present. The models played around with the position of the upcoming low pressure even at the 72 hr range only consolidating on the track and position 48 hrs in advance. Short term developments quickly scupper even reliable timeframes in volatile set ups as we have at present moving into mid month. 

Edited December 6, 2024 by damianslaw

[festivalking]

There seems to be continuous trend for the charts to slip into a more westerly component - with little HLB - don't shoot me but could it be the northern hemisphere is slipping into what the seasonal forecasts were suggesting.  This isn't a moan just a laymen's observation. Happy to be proved otherwise if you have evidence!

[feb1991blizzard]

 bluearmy

It looks very indicative of a fizzler to me, maybe a minor displacement at best.

Hardly any progress,  though i suppose as long as it keeps some kind of disconnect between strat and trop in terms of zonal winds it is doing its job, this was never going to be vortex obliterator.

[bluearmy]

 feb1991blizzard  If the trop patterns continue to be amplified then I can see the strat being markedly displaced somewhere on the Eurasian side.  But no sign of a split type event.   of course sig warming and a slowing upper strat vortex could flush down some mobility and possibly force a coupling into the trop.  If the strat is weakened then that’s  not a disaster although we could then see a recovering strat taking charge. 

the unluckiest outcome would be a strong warming high up flushing down mobility which flattens the NH amplifications. We’d then likely get a quick spv recovery and potentially a coupled vortex. 

 

Edited December 6, 2024 by bluearmy

[nick sussex]

 bluearmy

You mean the chance of pain without the gain .

It’s happened a few times over recent winters where a decent trop pattern was ruined by a warming which flushed down the mobility .

 

[Shaunado]

 Jacob Also known as Polar stratospheric clouds, kind of rainbow coloured and I believe can be best seen when high uppers are very low in  temperature. Rare in UK, but there was a widespread show last winter when a chunk of PV was over the UK, if I remember correctly.

Pic from Wikipedi:

[Mike Poole]

 bluearmy  nick sussex It seems to me that while the teleconnections perspective is holding firm in terms of potential, the list of possible ways that this could all go wrong is lengthening by the day…

[bluearmy]

 Mike Poole in the immortal words of Robert shaw …… we’re gonna need a bigger table!

[Gowon]

Lets pray it doesn't get too hot up there, then.

[northwestsnow]

 Mike Poole yep.

its not looking good,let's call a spade a spade here ...

[feb1991blizzard]

To be honest though, i am not sure anything will have necessarily 'gone' wrong, at no point has anything been consistently advertised that would bring any widespread cold spell or even small amounts of settling snow to anywhere south of here, to me a spell that has gone wrong was Dec 2012 where multiple outputs promised deep cold or earlier that year when a cold spell looked likely to last whole of Feb (even met office 30 dayer were on board) and 2019 too.

[Big Kev]

 northwestsnow We should still be optimistic. Hopefully a chance of SSW. Let’s hope it becomes calmer, with dry settled crisp weather heading up to the Christmas period. Then raging easterly’s. We can dream.

[Dennis]

are that the retro-signs to #christmasweek....the Beast 

there is still time my friends 

[nick sussex]

 Mike Poole

It’s a bit like heads you lose tails you lose !

Or perhaps welcome to UK winters. These strat warming’s are often a sheep in wolf’s clothing ! 

Anyway we live in hope ! 

[Dennis]

MJO 6-12

Edited December 6, 2024 by Dennis

[*Stormforce~beka*]

 Beanz The very reason I have this person on ignore. I just can't deal with a wall of text

[LRD]

52 minutes ago, Dennis said:

are that the retro-signs to #christmasweek....the Beast 

there is still time my friends 

"Cold to the left of me, cold to the right, here I am stuck in the middle without blue"

To incorrectly quote Stealers Wheel

Edited December 6, 2024 by LRD

[Dennis]

EC after midmonth 

hope the AO gets more effektiv 

[damianslaw]

 Dennis A number of expectations that the third week of Dec has a good chance of transitioning to something definitively colder with possible higher lattitude heights building favourably, alas the last few model runs of GFS and now ECM don't appear to be heading that way. However such timeframes still way beyond reliable and as I said that is 11th Dec at tops, so still time for things to sway back towards such scenario 3rd week of December.

There does seem a propensity for rapid cyclogenisis at present with low pressure systems suddenly gathering deepening, Storm Bert and now Darragh, hence I feel the medium range is prone to sudden short term developments making it prone to large scale room for marked error. 

Edited December 6, 2024 by damianslaw