Model output discussion - mid January

[Chesil View]

Nothing significant showing in the 144 range yet but hopefully that will have changed by midweek.  Things generally seem to be heading in the right direction and certainly the ensembles from both ECM and GFS keep showing us some great possibilties. Fergies tweet this morning was certainly interesting regarding UKMO thoughts on the ECM ensembles. As ever for now its a case of keeping the faith.

[bobbydog]

9 minutes ago, jvenge said:

Begs the question....

Who would actually want one mid feb? 

form an orderly queue... 

[feb1991blizzard]

15 minutes ago, jvenge said:

Begs the question....

Who would actually want one mid feb? 

Me please.

[Singularity]

It’s a fascinating scenario in the 7-12 day range, as we see an unusually vigorous vortex over Canada but also low heights in Europe (AAM response) which raises the potential for a major ‘mirror’ circulation I.e. anticyclone to spin up within a region spanning from the UK to E. Scandinavia or W. Russia.

Fine margins with respect to the latitude at which the ridge has its axis will make a huge difference to surface weather in the UK. 

Maldonado affected is just how much the unusually strong flow between the vortex and ridge is directed toward high polar terrain and deflected into the stratosphere to potentially hurt the stratospheric vortex a great deal.

Along with the MJO forcing this m a y then allow us to keep a blocking theme when otherwise it would simply be squashed out - but that’s getting ahead of reasonable consideration. Let’s get the cold in first... hopefully without too much drama (yeah, right...!).

Edited January 28, 2018 by Singularity

[Daniel*]

26 minutes ago, jvenge said:

Begs the question....

Who would actually want one mid feb? 

March can very much be a winter month I’d say it is for the far north. It isn’t ideal in the S the warm months I like to call them are long we have can 20C days in March all the way to late October again perhaps IMBY speaking, whereas cold months where freezing conditions are possible there’s a much more limited window. 

Edited January 28, 2018 by Daniel*

[simshady]

29 minutes ago, jvenge said:

Begs the question....

Who would actually want one mid feb? 

Count me in

[Snowman.]

1 minute ago, Daniel* said:

March can very much be a winter month I’d say it is for the far north. It isn’t ideal in the S the warm months I like to call them are long we have can 20C days in March all the way to late October again perhaps IMBY speaking, whereas cold months where freezing conditions are possible there’s a much more limited window. 

December and March are surprising equal in terms of snowfall just long lasting snow is harder to come by.

[snowray]

45 minutes ago, Ice Day said:

Indeed so, it has us in an easterly flow by 180hrs.  There are some stonking ensembles at 192 showing up as well, in fact a significant number I would say!

       

Yes some nice ens there. Looks like a rather cold mean starting on the 31st, -4/-5/-6c, so one thing that looks pretty certain now, February will start off cold and this theme might well continue to mid month, at least.

Edited January 28, 2018 by snowray

[Daniel*]

6 minutes ago, SN0WM4N said:

December and March are surprising equal in terms of snowfall just long lasting snow is harder to come by.

I recall more incidences of cold and snowy conditions in March certainly first half than December unsure if there are statistics to back that. IMO December is barely a winter month in the S, especially nowadays it seems. With March the SSTs are at their coldest less moderation from sea track, however it does become a challenge with being able to form a cold pool - continental cold March 2013 was so rare in that instance in its lateness. 

Edited January 28, 2018 by Daniel*

[karlos1983]

For sure March can dilever down south, but the further into March the less likely it is. And as Daniel says it’s hard to keep it in the ground for long in March. I’d rather be chasing some early spring warmth if I’m honest though after my winter cut off, March 15th! Cold rain is not nice. 

A good day today, the pendulum of hope seems to have swung back to a cold period of weather looking more likely as we head into February. Should be an interesting week of mode watching this week!

 

Edited January 28, 2018 by karlos1983

[SMU]

So annoying a whole post wiped out when the forum was down-

For fear of a people throwing their toys out the Pram I’m just going to run commentary on this evolution - no forecast as it’s going to be a close run thing - at least the most striking thing developing is the depth of cold on tap to the east which has been notable in its absence in the last few years -

So its all about ‘the Wedge holding in situ’ whilst waiting for the Atlantic ridge to pick it up ‘ 144-192 is that time!

This is the shape of the jet that’s beginning to develop @150

The acute flow will only stay like that for another 12/24 hours before the jet sweeps NE at mega speed

That acceleration will allow a ridge to move NE & if the residual heights ( wedge ) are in the correct place then it will feed nicely together-

So this is where we want our wedge of her heights

note NW of Scandi - also note the CAA deep into Western Europe...

From there the rest is fairly predictable

The high is closing off sending CAA westwards under the base-

Thats our route to an Easterly - If we have weaker residual heights then the High may be a little further south -

In terms of cold on tap - good timing for the first week of Feb- Climo indicates this is the lowest point in Winter ( ave for London is -3 ) & certainly -16c to the east is a fair shout

possibly Colder...

So this really does need to be the centrepiece of winter as If is missed wintertime will be ticking after day 10-15.

Were in the game people....

 

[CK1981]

11 minutes ago, Steve Murr said:

So annoying a whole post wiped out when the forum was down-

For fear of a people throwing their toys out the Pram I’m just going to run commentary on this evolution - no forecast as it’s going to be a close run thing - at least the most striking thing developing is the depth of cold on tap to the east which has been notable in its absence in the last few years -

So its all about ‘the Wedge holding in situ’ whilst waiting for the Atlantic ridge to pick it up ‘ 144-192 is that time!

This is the shape of the jet that’s beginning to develop @150

The acute flow will only stay like that for another 12/24 hours before the jet sweeps NE at mega speed

That acceleration will allow a ridge to move NE & if the residual heights ( wedge ) are in the correct place then it will feed nicely together-

So this is where we want our wedge of her heights

note NW of Scandi - also note the CAA deep into Western Europe...

From there the rest is fairly predictable

The high is closing off sending CAA westwards under the base-

Thats our route to an Easterly - If we have weaker residual heights then the High may be a little further south -

In terms of cold on tap - good timing for the first week of Feb- Climo indicates this is the lowest point in Winter ( ave for London is -3 ) & certainly -16c to the east is a fair shout

possibly Colder...

So this really does need to be the centrepiece of winter as If is missed wintertime will be ticking after day 10-15.

Were in the game people....

 

Are we looking at surface temperatures being approximately 10c higher than the 850’s?

[snowray]

38 minutes ago, SN0WM4N said:

December and March are surprising equal in terms of snowfall just long lasting snow is harder to come by.

I don't think so, the sun is at its minimum in Dec, 21st is the shortest day of the year of course, so any decent cold spell would feel bitter and settled snow would be hard to shift, by March the sun is at the spring equinox so much stronger particularly in the south so any snow that settles over night is gone by midday particularly in late March. I personally have never experienced a very cold March with Ice days and settled snow, ever, although I was told that they were more frequent pre 1960s.

One other thing, if cold starts in Feb with snow and hard frosts, then this can extend into early March if the cold stagnant air is left in situ over snowfields.

Edited January 28, 2018 by snowray

[Weathizard]

Not much difference between the GFS and ECM at day 6 then...

[Snowman.]

35 minutes ago, Daniel* said:

I recall more incidences of cold and snowy conditions in March certainly first half than December unsure if there are statistics to back that. IMO December is barely a winter month in the S, especially nowadays it seems. With March the SSTs are at their coldest less moderation from sea track, however it does become a challenge with being able to form a cold pool - continental cold March 2013 was so rare in that instance in its lateness. 

By MO averages they're roughly the same but snow cover is much lower in March.

https://www.metoffice.gov.uk/public/weather/climate/

[markw2680]

We go from millions of posts and pictures to absolutely nothing!! Where the hell is frosty these days?

back to the models I feel there will be lots of chopping and changing but hopefully will all lead to the train delivering the cold

[Snowman.]

7 minutes ago, snowray said:

I don't think so, the sun is at its minimum in Dec, 21st is the shortest day of the year of course, so any decent cold spell would feel bitter and settled snow would be hard to shift, by March the sun is at the spring equinox so much stronger particularly in the south so any snow that settles over night is gone by midday particularly in late March. I personally have never experienced a very cold March with Ice days and settled snow, ever, although I was told that they were more frequent pre 1960s.

One other thing, if cold starts in Feb with snow and hard frosts, then this can extend into early March if the cold stagnant air is left in situ over snowfields.

I was talking snowfall. Snow cover is much lower. And March 2013 was our last one with Ice Days down here.

Edited January 28, 2018 by SN0WM4N

[snowray]

42 minutes ago, Daniel* said:

I recall more incidences of cold and snowy conditions in March certainly first half than December unsure if there are statistics to back that. IMO December is barely a winter month in the S, especially nowadays it seems. With March the SSTs are at their coldest less moderation from sea track, however it does become a challenge with being able to form a cold pool - continental cold March 2013 was so rare in that instance in its lateness. 

Interesting that the best snow that I have had in the last 10 years was from the late Nov to 1st/2nd December around 2010/2011, apart from that the infamous February Thames streamer from about 2009. 

I actually missed March 2013, was out of the country.

Edited January 28, 2018 by snowray

[SMU]

14 minutes ago, CK1981 said:

Are we looking at surface temperatures being approximately 10c higher than the 850’s?

11c ish -

ECM / UKMO broadly similar with a more aggressive low pressure around 144-168 taking a slightly different direction to the GFS I highlighted - although depending on the rushing could be similar by 192-

S

Edited January 28, 2018 by Steve Murr

[SMU]

ECM similar but quite progressive @192

[Weathizard]

ECM 192 is pretty poor to be brutally honest. The differences at only 144 though mean it should be taken with a serious spoonful of salt.

[SLEETY]

Still think it be a miracle if we get a deep cold Easterly,that’s how it is in our climate now,you only have to look at the past 30 years to see that

Wait until said Easterly appears at t96 if it ever get that close....

Edited January 28, 2018 by SLEETY

[SMU]

JMA profiles same as GFS

which means it will be very good-

Very difficult call this would be - So just let it roll... 

[Daniel*]

1 minute ago, Weathizard said:

ECM 192 is pretty poor to be brutally honest. The differences at only 144 though mean it should be taken with a serious spoonful of salt.

Well fine margins here I wouldn’t say poor it’s still very cold in the S/E albeit dry.

[Matthew.]

If it wasn’t for the huge purples around Greenland we could be in the money. Longer term this could change though but I’m not so sure