Model output discussion - Winter approaches

[Decemberof2010]

I know some people disagree with cherry picking one random ensemble at over 10 days out. That’s why this evening I’ve cherry picked 2

[SMU]

^^^ -14c uppers in the SE from a Northerly

[weirpig]

3 minutes ago, Allseasons-si said:

Not kidding JFF,there is only two that show this potent northerly,pert 5 and 30

most of them show benign conditions but cold.

 

Err  right  I know.   I was just asking a question when did a chart like that  come to fruition    and what does jff mean ? 

[Paul_1978]

4 hours ago, Snow lover 2020 said:

Omg we are getting hints maybe for a beast from east possibly from that chart!!!

I’m certainly seeing something blocked on the horizon - my blocked list. 

[Kirkcaldy Weather]

On 16/11/2020 at 13:15, Kirkcaldy Weather said:

Well we got the ridge but were unlucky with too much energy going over the top and flattening it.

Positive to see the models attempting for a second try at the scandi high route this seems like the direction (hopefully) we are headed with it fitting in with phase 1 / 2 of the MJO in November, quite a few look very battleground type setup to me which can always have a chance of delivering some big snowfalls in the uk but we can worry about the finer details once we see how things develop.  there was one that looked a bit more iffy suppose there’s always the chance of the high being that bit too far east 

But again positive signs from my perspective and hopefully some lovely charts coming our way ️

Looks like we aren’t too far off these patterns starting to unfold over the next week or so, the first bit of interest remains that little cold pool that drops out of Scandinavia as the higher pressure builds there, looks like the models will continue to have a bit of a disagreement trying to pinpoint where it ends up and just how low the 850 temps will be but I wouldn’t rule out the chance of a bit of wintry weather for the UK should it head our way, then looks like lower pressure to the south which is usually a decent sign of blocking somewhere to the north whether that be scandi or toward Greenland looks to be the next big question but certainly not a mild zonal setup from what I’m seeing currently  

[booferking]

14 minutes ago, Steve Murr said:

^^^ -14c uppers in the SE from a Northerly

2020 anything possible

[Daniel*]

EPS NAO forecast compare with a day ago I like what I’m seeing, good expectation for -NAO in first week of December the cold northerly patterns aren’t something being pulled out a hat...

[kold weather]

So there is definately a path towards sustained cold on the models but its a really messy path, we could just as easily see the LP sink SSW and us end up in a southerly airflow followed by a toppled HP that morphs back to a Euro High.

There seems to be a theme on the models for LP to move SSE close to the UK past day 8. Its a pattern that will make it very tricky for any milder air to try and come in at least at the surface, however its also a pattern that will take some time to bring in much colder air unless we get a lucky break with the positioning of everything, and lets be honest, when was the last time that happened! If you want to see a version of that, look at Ptb.5 on the GFS ensembles, an utter monster of a cold run.

In the shorter term, we have got a cool, possibly frosty outlook depending on cloud cover (but either way suppressed surface temps) with maybe a chance of something trying to sneak in from the east briefly?

[Allseasons-Si]

22 minutes ago, weirpig said:

Err  right  I know.   I was just asking a question when did a chart like that  come to fruition    and what does jff mean ? 

Yes,sorry

i don't want to derail the thread and this question is probably suited to the historic thread but i don't know this without digging through the archives and it could take a while,i looked online too but to no avail>maybe never!

JFF is (just for fun)

anyway,i should head back to MOD

and the gefs mean at day ten looks V good...i mean very good

 

[Allseasons-Si]

There is a lot of ridging to our west on the extended gefs ens,that is encouraging.

Edited November 25, 2020 by Allseasons-si

[Daniel*]

You see in successive ECM det runs the trend for more -AO and -NAO. The trend is our friend.
 

ECM 12z was impressive in that respect, strongly negative NAO the AO not shabby either forecasts been more unsure with AO, yet a lot of folk not satisfied, it highlights to me we have seen too much good output, more of a slow burner but perhaps this route would be more sustaining for a future cold spell.

[Mark wheeler]

39 minutes ago, Steve Murr said:

^^^ -14c uppers in the SE from a Northerly

Bank

[kold weather]

16 minutes ago, Daniel* said:

You see in successive ECM det runs the trend for more -AO and -NAO. The trend is our friend.
 

ECM 12z was impressive in that respect, strongly negative NAO the AO not shabby either forecasts been more unsure with AO, yet a lot of folk not satisfied, it highlights to me we have seen too much good output, more of a slow burner but perhaps this route would be more sustaining for a future cold spell.

Looking at the ECM ensembles members individually there is a somewhat stronger agreement tonight of keeping HP more in charge than it is on the GFS, especially over Scandinavian regions, and instead the LP is forced southwards/SSW. I'm guessing that is also starting to show on those NAO forecasts as well from the ECM det.

It means we end up pulling in either a very lukewarm easterly (not cold enough for much given above normal SSTs and above normal soil temps) or a SSe airflow. Both would probably be below average still but we'd need to see a somewhat different type of pattern to get anything meaningful in terms of cold/snow potential if that were right. Cool more than outright cold probably in those solution

It could also mean in theory we end up with cracking northerly blocking and still keep a somewhat poor outlook dominated by the southern flow of a LP to our SW.

There are some northerly airflows in the mix as well, but they are not what the 12z ECM ensembles favoured. 

Plenty of time for both up and down grades at the moment, and lets hope models continue to strengthen the easterly flow into something that could be useful in the medium term.

Very subtle long term hints from both ECM/GFS ensembles that the atlantic northern arm of the jet re-strengthens towards the very end of the runs. Nothing to yet be worried about, but when both sets of ensembles pick up that signal even that range its worth keeping an eye on. Also worth remembering, that doesn't necessarily mean a rampant Atlantic either, especially if we have the right blocking pieces in play.

Edited November 25, 2020 by kold weather

[A Frayed Knot]

Fantastic posts reading through them all... Bring back the old skool winters I say. 

Oh yes they are on there way, glad of this lockdown, no pollution and the world is back on track with proper Winters ahead

[Relativistic]

2 hours ago, weirpig said:

Just for fun  but pert 5 goes for -12 uppers across the country from a northerly   with colder air to follow     when was the last time that happened? 

March 2018.

[northwestsnow]

Gfs 00z looks very seasonal with lots of frost fog etc over the coming week or more....

Bank ...beats wind and rain every time for me personally...

[swfc]

1 minute ago, northwestsnow said:

Gfs 00z looks very seasonal with lots of frost fog etc over the coming week or more....

Bank ...beats wind and rain every time for me personally...

It does nw which like you say better than the usual west to east flow. For what it's worth like I said yesterday I still think given so much blocking west and east a block sitting over the UK is probably the outcome over the next 10 - 14 days

[sheikhy]

Very cold and frosty ukmo gfs and ecm so far!!i take that for now!!still think there might be some changes with the initial easterly around 96 to 120 hours!!

[Griff]

Spare a thought for those of us getting absolutely 'snowed under' at work currently, only occasional lurking and no time to comment. 

Looking tasty... 

At least it's a break from permanent autumn. 

Edited November 25, 2020 by Griff

[sheikhy]

Ecm 192 hours❄!!!!cold pool from continent and low sliding into spain from the atlantic!!!

[Ali1977]

ECM at 216 could definitely produce some flurries in the SE, a chilly flow in this run and again the low heading towards Spain is a big piece of a cold puzzle coming together. 

[IDO]

The GFS 0z op has lost the amplified upstream that the 12z had and that means a flatter profile in our region:

d8-d16 gfs>>   d11 gefs>>> 

Late on, we get a bit more forcing. All academic as I suspect the models are clueless after D8. Looking at the D11 GEFS and they are showing entropy on a grand scale, a ragtag bunch TBH. ECM at D8 is similar to last night's run:

ecm d8 0z>>  ecm d9 12z yesterday>> 

ECM has the trough dropping too far west.

GEM is keeping the potential for a northerly and maybe the best in the short term:

 

[swfc]

Yes IDO ec at least consistent from yesterday's 12z.things to the east just not rite are they in regard to the position of the high, to far south and shape etc. Jet to the south but in the UK not really bringing much benefit to our neck of the woods. day ten brings the Atlantic high into play heading into greenland againGod loves a trier eh

Edited November 25, 2020 by swfc

[mb018538]

ECM day 10 is interesting from the perspective of being very blocked and having a complete shutdown of the Atlantic storm train. PV has been sent across to Siberia:



On the downside, we get a low anchored off the coast of Iberia sending mild air flooding across western Europe. No cold air in place at all:

[sheikhy]

Got a feeling we gona see a big set of 12zs this evening and in a good way as well if cold frosty and snowy weather is ur thing❄!have i just gone and jinxed it