The hunt for cold - Model discussion (late November)

[Staffordshire]

10 minutes ago, MattStoke said:

Both often bring more wintriness than December, from personal experience.

April is often more transient I find, I think it is just a case of never really getting lucky synoptic wise in December. Look at last year, December was a great month for many, and of course 2010. December can definitely deliver better than April, it is just a case of getting lucky, but when we do, it is certainly cold enough for substantial snow, more so than the transient stuff in April.

[Duane S.]

On 10/12/2018 at 11:32, s4lancia said:

Going down... Bottom floor...

It's getting there hopefully. With one slightly bonkers member going for -20 m/s. In December!

 

 

I guess this has already been posted. It certainly looking odds-on for an SSW just after Christmas then. Will be a case of waiting to see how this pans out. Gives us an extra couple of tickets for the raffle, that's for sure.

 

[MattStoke]

6 minutes ago, Staffordshire said:

April is often more transient I find, I think it is just a case of never really getting lucky synoptic wise in December. Look at last year, December was a great month for many, and of course 2010. December can definitely deliver better than April, it is just a case of getting lucky, but when we do, it is certainly cold enough for substantial snow, more so than the transient stuff in April.

Indeed. A December cold spell will be more significant than an April one but more cold spells seem to occur during April (From personal experience. Records may say otherwise). Most Decembers are more like a continuation of autumn than a winter month.

Reckon this could well be the case this time round.

Edited December 13, 2018 by MattStoke

[MP-R]

6 minutes ago, Staffordshire said:

April is often more transient I find, I think it is just a case of never really getting lucky synoptic wise in December. Look at last year, December was a great month for many, and of course 2010. December can definitely deliver better than April, it is just a case of getting lucky, but when we do, it is certainly cold enough for substantial snow, more so than the transient stuff in April.

Indeed. No matter what anyone says, December is more wintry than April and is more likely to get widespread snow than April. In spring it's only really the first half of March which can compete with the first half of December - the second half of December is generally more wintry than the second half of March and onwards. Wintry synoptics on the other hand... as you say, sometimes April really does tease us and we think, if only this was winter - the typical adage of getting the right synoptics at the wrong time of year. Rather similar to the somewhat autumnal synoptics we're still experiencing even into December.

[huntso]

I was born on Dec 22nd 1958 and  have never seen it snow on my birthday.

Admittedly I have spent most of it in London and Easy Anglia so not that surprising I suppose. Got lucky in 1986, went to Igls near Innsbruck and it hardly stopped all week, but that's cheating

Not expecting that to change this year, just have to shoot off somewhere a bit more wintry

 

[bluearmy]

13 minutes ago, s4lancia said:

I guess this has already been posted. It certainly looking odds-on for an SSW just after Christmas then. Will be a case of waiting to see how this pans out. Gives us an extra couple of tickets for the raffle, that's for sure.

From the blue book ..........

[Froze were the Days]

47 minutes ago, Ed Stone said:

With so many indicators suggesting a back-loaded winter, and even the Met hinting at some fun-and-games in early January, just how memorable might this winter be? A lot of time has passed, since February 1947...

It will be memorable but for the wrong reasons...it will become known as the 'Brexit winter', a lot of expectation, hot air without much happening!

Edited December 13, 2018 by Froze were the Days

[BLAST FROM THE PAST]

53 minutes ago, lassie23 said:

It's cold today, the hunt is over

Indeed, cold yesterday too....maybe we should have ‘hunt for a freeze’

 

BFTP

[coldie]

5 minutes ago, huntso said:

I was born on Dec 22nd 1958 and  have never seen it snow on my birthday.

 

I know how you feel, I was born on christmas day and have never seen snow on my birthday and I probably never will!

[Stu_London]

SSTs are lower in early April than December meaning less modified air masses

The Jet tends to ease off as well as the Vortex collapses leading to a less westerly regime.

Humidity tends to be lower in April also which supports snow falling through the air at higher temperatures.

However a prolonged cold spell over several days with laying snow at low lying areas is very much possible in December and might occur on average every 5-10 years whereas in April it is almost impossible.

 

[MattStoke]

1 minute ago, coldie said:

I know how you feel, I was born on christmas day and have never seen snow on my birthday and I probably never will!

Reverse psychology - I like it

Edited December 13, 2018 by MattStoke

[Methuselah]

From a strictly inland perspective, late March and early April are the time when convection gets going and uppers are often still quite cold; I think it's in showery conditions that gives springtime so many days with snow falling...? Should any snow lie, it usually melts within about 10 minutes, though.

[Ross90]

In terms of days where snow falls the first half of dec and first half of apr have been fairly even where i am over the last 20 years.The days where snow actually settles is miles apart though, i've never seen snow settling and staying around for more than a few hours in April compared to lying snow for 24 hours + in at least half of the Decembers that i can remember.

[johnholmes]

44 minutes ago, Devonshire said:

John, I can see the logic of this in terms of expectation management (and emotional resilience!) - but this begs the question - that has probably been asked (and answered) before somewhere;  are the 0, 6, 12, and 18z runs (e.g. for GFS) different in the assumptions, algorithms, no. of data points built in (or anything else) - or is it simply a case of different starting data being put in? (notwithstanding weather balloons avoiding Santa's sleigh over Christmas and related myths)

I'll try to answer you D although my knowledge of just what goes in, now 25 years since I was professionally involved, is that data is basically the same regardless of the time, ie surface reports. Then it gets more complex with upper air data usually being simply, as with the surface data, just transposed by 12 hours, ie 00 and 12 z, less data at 06 and 18 z. Aircraft reports will also be more at certain data times. Then the models are simply set to go and carry on be it 00, 06, 12, 18 to their time end based on the same rules/laws etc.

Thus I feel that 00 and 12 data sets are better, or were. Of course the usual myhs you quote re missing data over Xmas, and it is a myth, usually only brought out if the models do not show cold scenarios.

The other point I was making is comparing like with like time outputs, is a valid one at time scales beyond 144 h perhaps 168h. Ftom 144h down then comparing successive runs is fine as the later data will over=ride data amounts.

Hope this helps?

 

[bluearmy]

4 hours ago, Kentspur said:

How accurate are these 10HPA zonal winds forecasts? I don't want to sound negative but that's a dramatic change from previous days. With the CFS showing the majority much closer to average through much of the winter now after the initial drop in December 

I wouldn’t be concerned about anything the CFSv2 shows ........it’s up and down like a tarts draws ......

[Mucka]

Unusual to see GFS be the model keen on undercut and blocking while ECM rejecting it, a bit of role reversal there.

We may not have to wait very long for this to be settled though.

Both GFS 6z and GFSp 6z moved more toward ECM and the GFS ooz operational output had little to no backing from the ensemble suite so it is more likely its 12z output will do away with the undercut than ECM get on board.

The one ray of hope is that 6z output tends to be rather progressive.

It would be great to see GFS with a coup in modelling an unexpected cold spell so fingers crossed this evenings output shows just that.

Edited December 13, 2018 by Mucka

[Frosty.]

The hunt for cold is about to bear fruit, some snow to come in the short term further n / e..especially at elevation and I have a very good feeling about the extended outlook at Christmas or soon after..I think coldies have plenty to smile about..cr*p mild mush looks in short supply and for a change..predominantly colder weather looks the form horse!!!!!..fingers crossed fellow coldies!

[phil nw.]

Just scanning the outputs and there's little of any interest from a cold pov out to day 10 with the onset of the westerlies over the weekend.

Something in the eps clusters caught my eye though beyond that with the main group showing a sharp ridging from Iberia north over t he UK an d by day 15 we see this. 

It could be the start of a move to a Scandi.block with those +ve ht anomalies up there- or it may be transient as the 2 smaller clusters show more of the jet pushing through.

A pity we can't see the upstream flow and the polar field but just seeing that small area there are signs of some energy undercut from the Atlantic trough and as we can expect by that stage a slowing down of zonal winds it may develop into something.....

[bluearmy]

4 minutes ago, phil nw. said:

Just scanning the outputs and there's little of any interest from a cold pov out to day 10 with the onset of the westerlies over the weekend.

Something in the eps clusters caught my eye though beyond that with the main group showing a sharp ridging from Iberia north over t he UK an d by day 15 we see this. 

It could be the start of a move to a Scandi.block with those +ve ht anomalies up there- or it may be transient as the 2 smaller clusters show more of the jet pushing through.

A pity we can't see the upstream flow and the polar field but just seeing that small area there are signs of some energy undercut from the Atlantic trough and as we can expect by that stage a slowing down of zonal winds it may develop into something.....

Was just looking at those clusters and wondering which one fits Exeter’s latest musings .... possibly cluster 1 but I feel that the 00z suite doesn’t fit with the latest glosea run ....their musings becoming ever more indicative of a proper wintry spell in the new year .....10pm tonight we will be checking weeks 3 and  4 on the ec 46!  

[booferking]

3 minutes ago, bluearmy said:

Was just looking at those clusters and wondering which one fits Exeter’s latest musings .... possibly cluster 1 but I feel that the 00z suite doesn’t fit with the latest glosea run ....their musings becoming ever more indicative of a proper wintry spell in the new year .....10pm tonight we will be checking weeks 3 and  4 on the ec 46!  

But do any of them clusters fit in with  Exeter for period around Christmas and shortly after they say northerly or northwesterly regime -  cluster 1 wouldn't produce northerly northwesterly regime?

[phil nw.]

1 minute ago, bluearmy said:

Was just looking at those clusters and wondering which one fits Exeter’s latest musings .... possibly cluster 1 but I feel that the 00z suite doesn’t fit with the latest glosea run ....their musings becoming ever more indicative of a proper wintry spell in the new year .....10pm tonight we will be checking weeks 3 and  4 on the ec 46!  

News of the ec46 probably will be more revealing as to which way things may be going.

Nothing really catching my eye yet Blue in the day 15 gef set with only weak anomalies plastered everywhere but the eps are at least hinting at something interesting by then.

It seems many cold roads( indicators) are heading for around or just after Christmas.We should expect quite a weak Atlantic by then if these signposts are correct(zonal wind forecasts,tropical convection etc).Some reasoning to hope for heights to build further north as any sub-tropical ridging should become more pronounced in a weaker and buckling jet flow.

Still at this range we have to say it still speculation.

[Frosty.]

10 minutes ago, phil nw. said:

News of the ec46 probably will be more revealing as to which way things may be going.

Nothing really catching my eye yet Blue in the day 15 gef set with only weak anomalies plastered everywhere but the eps are at least hinting at something interesting by then.

It seems many cold roads( indicators) are heading for around or just after Christmas.We should expect quite a weak Atlantic by then if these signposts are correct(zonal wind forecasts,tropical convection etc).Some reasoning to hope for heights to build further north as any sub-tropical ridging should become more pronounced in a weaker and buckling jet flow.

Still at this range we have to say it still speculation.

Certainly more reasons for coldies to be positive than usual!..great update from exeter post crimbo and especially new year onwards..I'm a happy coldie and in the short term..some will see snow / snaw cover in the next few days..all in all..not your typical cr*p mild mush fest to endure!!

Edited December 13, 2018 by Frosty.

[northwestsnow]

7 minutes ago, phil nw. said:

News of the ec46 probably will be more revealing as to which way things may be going.

Nothing really catching my eye yet Blue in the day 15 gef set with only weak anomalies plastered everywhere but the eps are at least hinting at something interesting by then.

It seems many cold roads( indicators) are heading for around or just after Christmas.We should expect quite a weak Atlantic by then if these signposts are correct(zonal wind forecasts,tropical convection etc).Some reasoning to hope for heights to build further north as any sub-tropical ridging should become more pronounced in a weaker and buckling jet flow.

Still at this range we have to say it still speculation.

Absolutely agreed Phil..

I want to see EC moving away from its 00z run ..

[johnholmes]

45 minutes ago, Ross90 said:

In terms of days where snow falls the first half of dec and first half of apr have been fairly even where i am over the last 20 years.The days where snow actually settles is miles apart though, i've never seen snow settling and staying around for more than a few hours in April compared to lying snow for 24 hours + in at least half of the Decembers that i can remember.

Yes snow falling is a very different matter to it lying for any length of time. Surely it stands to reason that, given similar synoptics, that it is far more likely to lie when the sun is at its lowest, ie: December into January?

[phil nw.]

11 minutes ago, northwestsnow said:

Absolutely agreed Phil..

I want to see EC moving away from its 00z run ..

It may look better soon nws if it's later clusters mean anything.Day 10 at the moment maybe just to soon to pick up the hoped for change.