The hunt for cold - Model discussion (late November)

[frosty ground]

Westerly all the way



Not stupidly mild but plenty of rain on the way, no real cold shown either just the occasional visit to the -5 line from a few rouge runs.

Barley a frost to be seen

Edited November 28, 2018 by frosty ground

[weirpig]

To be honest  its what to expect in early December.  im sure in a few days if not earlier  the models will become better in terms of height rises and colder weather.  Ps  i see the put downs have taken on a more adroit form     to be honest i didnt even realise the big white bearded fella even had a brigade 

[mulzy]

17 minutes ago, tight isobar said:

Rubbish....???

There as mixed out-and @odds as the ops !!!!

As we stand!

They are poor mate.  Dec 1-10 CET *could* be +2C above normal looking at the charts out to 10/12 days.  We are in desperate need for something to change the zonal outlook.  If this was the "hunt for mild", we'll all be saying things are aligning perfectly.

On the other hand, today is November 28th so plenty of time for things to change for the better.

[Methuselah]

So even the para doesn't charge in on a white charger:

But there's always the chance that the 12Z will conjure-up a real stonker? Won't change the weather, though...

[bluearmy]

The gets continue to show plenty of upstream energy to interfere with the repeated attempts to amplify - add in the polar high and it’s unpredictable nature and you have a recipe for chaotic nwp 

i still maintain we are at 50/50 re proper cold by mid December - no way will the low res gefs be getting things right as week two progresses - the mean anomaly’s will give a loose indication but nothing more than that .....

the eps running at a resolution similar to gfs op are clearly struggling 

[tight isobar]

6 minutes ago, mulzy said:

They are poor mate.  Dec 1-10 CET *could* be +2C above normal looking at the charts out to 10/12 days.  We are in desperate need for something to change the zonal outlook.  If this was the "hunt for mild", we'll all be saying things are aligning perfectly.

On the other hand, today is November 28th so plenty of time for things to change for the better.

Yeah-agree..

But the point of note AGAIN- is the notion of divergence...across the raws!!..

And ens will and do react to that!!..

As the mean-and spread are indicating!!.

@scatter.

Imo its primmed for flip into new month (weekend)...

As again the polar situ..amd overall norn hem is eye waterng..at times...and continues the route...lets see aye!!!

Edited November 28, 2018 by tight isobar

[Met4Cast]

lol at the number of people taking day 10/12 charts seriously when they can't even get consistency for day 6/7. 

Quite frankly anything past day 6 may as well be drawn by a 5 year old, they're absolutely meaningless given the uncertainty/massive spread within not only the GEFS but the EPS too. 

[feb1991blizzard]

6 minutes ago, bluearmy said:

The gets continue to show plenty of upstream energy to interfere with the repeated attempts to amplify - add in the polar high and it’s unpredictable nature and you have a recipe for chaotic nwp 

i still maintain we are at 50/50 re proper cold by mid December - no way will the low res gefs be getting things right as week two progresses - the mean anomaly’s will give a loose indication but nothing more than that .....

the eps running at a resolution similar to gfs op are clearly struggling 

really????    i would have it at 0% - i always thought you were a realist coldie.

[Met4Cast]

2 minutes ago, feb1991blizzard said:

really????    i would have it at 0% - i always thought you were a realist coldie.

Has Ian Brown hacked your account or something?

[Polar Maritime]

Let's please keep posts balanced and polite please, Thanks.

[feb1991blizzard]

Just now, Daniel Smith said:

Has Ian Brown hacked your account or something?

Ensembles are there for the 15d range, because no resolution currently available can deal with the atmospheric dynamics involved to make a d15 forecast, thats why they change the starting data, yet no gefs member gets in deep cold even with some of them tweaked with a bias towards that?

[Met4Cast]

Just now, feb1991blizzard said:

Ensembles are there for the 15d range, because no resolution currently available can deal with the atmospheric dynamics involved to make a d15 forecast, thats why they change the starting data, yet no gefs member gets in deep cold even with some of them tweaked with a bias towards that?

So that means they must be right about no deep cold at the 15 day range, then?

[feb1991blizzard]

Just now, Daniel Smith said:

So that means they must be right about no deep cold at the 15 day range, then?

Yes IMO, look if people want to challenge me to a forecasting competion for December, i would wecome it.

[swfc]

Just now, Daniel Smith said:

So that means they must be right about no deep cold at the 15 day range, then?

Hi daniel.whats leads you to think there is any deep cold in the pipeline that far out given our usual west to east general weather?

[frosty ground]

1 minute ago, Daniel Smith said:

So that means they must be right about no deep cold at the 15 day range, then?

People can only say what they see, and there is no deep cold are even frosts to be seen for England.

Scotland being closer to the boundary layer will see frost and snow from time to time, but that's about it.

[frosty ground]

The last 4 GEFS output. Out of 60 runs only 1 hits the -10 line and only a few hit -7/8

No Deep cold on the horizon, of course it may change but on this evidence the next 15 days are westerly and wet

[tight isobar]

Until there are any 'definitive' clustering sig's-via ens- 

Then i cant see what this is all about!??.and there clearly isn't!!

Topping that with the fantastical synoptics..for blocking/northern hem structure/dissaryed polar vortex..

I know where my bets are going.

And yes a netweather members-dec-forecast would be a great idea!!!

Im in....

 

Edited November 28, 2018 by tight isobar

[SLEETY]

13 minutes ago, feb1991blizzard said:

Ensembles are there for the 15d range, because no resolution currently available can deal with the atmospheric dynamics involved to make a d15 forecast, thats why they change the starting data, yet no gefs member gets in deep cold even with some of them tweaked with a bias towards that?

But you just said no resolution can make a forecast at 15 d range then you said no gfs member gets in deep cold .

 

See the problem with what you said 

 

[MP-R]

All very November 2009esque. Amazing what an Atlantic-dominated outlook it is given what a mess it is over the Arctic - 'bad luck' comes to mind. Those heights over Iberia don't help either - they're essentially helping waft horrendously mild air over us and heights to the east are stopping lows get too far past the UK so we're just left in a yawnfest of southwesterlies. Needless to say though, things can and will change very quickly. Even the most unsettled of starts to December have brought a rapid turn around before mid month. Two examples:

2007

   

2002

 

 

 

We could just do with a long enough break between lows (which seem to form like lightning considering it's now December) as I think ridging from the south would very quickly rise through the UK given the chance. Just a shame we have to wait for interest while putting up with such garbage in the meantime.

[feb1991blizzard]

1 minute ago, SLEETY said:

But you just said no resolution can make a forecast at 15 d range then you said no gfs member gets in deep cold .

 

See the problem with what you said 

 

thats why they tweak the ensembles

[bluearmy]

6 minutes ago, frosty ground said:

The last 4 GEFS output. Out of 60 runs only 1 hits the -10 line and only a few hit -7/8

No Deep cold on the horizon, of course it may change but on this evidence the next 15 days are westerly and wet

December doesn’t require below -8c to bring deep cold (or snowfall) on a continental feed 

@feb1991blizzard - I am being realistic - 12/18 days is a long time - even Exeter are actually talking about possibilities of snow showers back end week 2 - low probability but then they would say that ........ give it until the back end of the week until we see the polar profile settle down somewhat - then my percentages will be re assessed. 

[Met4Cast]

19 minutes ago, swfc said:

Hi daniel.whats leads you to think there is any deep cold in the pipeline that far out given our usual west to east general weather?

Good question. 

I've not stated that I'm expecting deep cold, I'm with Bluearmy sitting on the 50/50 fence. But there's a few reasons why I think the Atlantic onslaught is going to be temporary and why I think a return to a more blocked pattern come mid-December is likely.

Reason 1: EPO/NAO

EPO is currently expected to go more negative and this supports troughing across the Eastern Seaboard and a more active Atlantic Jet (this is being seen currently/forecast on most models) In response we also see the NAO trending more positive

The AO is expected to remain negative throughout, for what it's worth, even becoming more negative than it currently is

14 day EPO forecast is suggestive of a return to neutral/positive after a short negative dip, I expect the NAO forecast to trend more negative once again when that takes place.

Reason 2: MJO

Phasing through 8-1 as we go into December, whilst amplitude should be enough to at least trigger the Atmsophere to produce some sort of blocking response, add the lag and that takes us to around December 15th

Reason 3: EPS/GEFS ensembles (EPS left)

I know I said the ensemble means are useless at that range in this situation in a previous post and to a large extent, they are. However, there's agreement between both models for heights towards Northern Scandi/across much of the Eastern Arctic days 10>16. The Atlantic trough more prominent on the EPS is almost non-existent on the GEFS means = huge uncertainty. 

However, what is rather certain in the Arctic blocking and heights towards the Scandi region. EPS also has a clustering of colder solutions in the extended, though given the spread not much can be gleamed from that

Comparing all the Deterministic runs, there's a clear though not major signal for a cooling trend towards the end of the first week of December, also note the reduced PPN signal suggesting an Atlantic onslaught is unlikely to continue

So.. deep cold? I'm not sure, that of course depends where the blocking sets up/if we can tap into the cold air, as others have said there's not really a signal for "deep cold", however. 

Neither is there a signal for a continuation of mild, Atlantic, wet dominated weather, either..

That's my reasoning/why I expect a blocking theme is more likely going towards mid-December, away from the Operationals I'm struggling to see a prolonged zonal signal within the models/background signals.

Going from GP's posts too (a little above my pay grade), various other signals other than the ones I've mentioned in this post are also suggesting zonal weather through December is unlikely.

 

Edited November 28, 2018 by Daniel Smith

[Penicuikblizzard]

So!! A couple of weeks ago the charts were showing bitter cold all the way,,,now they are showing mild! who is to say it won’t revert back in a couple of weeks?

Face it December is rarely a wintery month in the uk,,,,let’s get the the building blocks in place for a cold Jan/Feb 

[frosty ground]

26 minutes ago, bluearmy said:

December doesn’t require below -8c to bring deep cold (or snowfall) on a continental feed 

 

Indeed but did you miss my post that showed 2m temps which showed barley a frost for the next 15 days?, pretty sure deep cold would at least register a frost.

Snowfall chances are at 10% as you would expect from brief north westerlies.

I also stated that only a handful of runs hit the -7/8 mark.


 

[ICE COLD]

Just a quick question for the Mods , how come you can’t see who is viewing this topic at the bottom of the page anymore??