Model output discussion 25th Jan - The final third of winter beckons..

[Snowyowl9]

Last 2 winter easterlies.

Much stronger scandi high this time round.

http://.wetterzentrale.de/pics/Rtavn1201.html

[Connor Bailey Degnan]

Given the Meto update, and slight upgrades on snow potential, I'm slightly more optimistic today.

[Ali1977]

METO for next Fri, how does this compare with the latest GFS do we think?

scandy high slightly lower but WAA in Atlantic coming in higher round the LP to our south.  Not sure if this is better or not!!

Could do with the LP moving East a little 

Edited February 5, 2017 by Ali1977

[Frosty.]

Plenty of cold / wintry weather on the GEFS 6z

Hoping we are looking at cold weather becoming entrenched for more or less the month ahead!

Edited February 5, 2017 by Frosty.

[Luke Attwood]

1 minute ago, Frosty. said:

Plenty of cold / wintry weather on the GEFS 6z

Hoping we are looking at cold weather becoming entrenched for more or less the month ahead!

Well I do hope you are right,but should remain cautious its only one run 06z which was great. Having said that I do believe we will see cold weather starting Wednesday and probably lasting until Monday or Tuesday the following week at least! During this period we likely to see temps range from about 3-6c and and as low as -3 overnight. That's just my opinion looking at the models. I really hope we can repeat it on the 12z

[BARRY]

1 minute ago, Frosty. said:

Plenty of cold / wintry weather on the GEFS 6z

Hoping we are looking at cold weather becoming entrenched for more or less the month ahead!

This is all hoping the GFS is right, it has so far this winter Been unreliable, where as the UKMO has the last laugh on all the models lets see what the UKMO has to say before we go predicting cold runs.

 

[Frosty.]

4 minutes ago, Luke Attwood said:

Well I do hope you are right,but should remain cautious its only one run 06z which was great. Having said that I do believe we will see cold weather starting Wednesday and probably lasting until Monday or Tuesday the following week at least! During this period we likely to see temps range from about 3-6c and and as low as -3 overnight. That's just my opinion looking at the models. I really hope we can repeat it on the 12z

Well I hope I'm right, it looks like the best spell of the winter so far nationwide according to most of the models, hopefully it can go from strength to strength..been waiting all winter for a spell like this

[Luke Attwood]

4 minutes ago, Frosty. said:

Well I hope I'm right, it looks like the best spell of the winter so far nationwide according to most of the models, hopefully it can go from strength to strength..been waiting all winter for a spell like this

Yes how long u think it will last then,your opinion?

Edited February 5, 2017 by Luke Attwood

[Frosty.]

2 minutes ago, Luke Attwood said:

Yes how long u think it will last then,your opinion?

Difficult to say but strong scandi blocking can be hard to shift once firmly established so we could stay predominantly on the cold side with a mix of deep cold / surface cold for 2 to 3 weeks.

[Mark Parsons]

This is looking really good, a classic pre 2000 scandi high setting up something of a rarity in our modern winters and something many on here have not experienced........however caution as ever because as we know easterlies can flip at short notice but what may help this one succeed is the pending SSW.

Great respect to Steve Murr on his knowledge on the subject of easterlies ,i'm right up there with you Mr and know exactly where you are coming from, happy days!  

[phil nw.]

We don't get many easterlies these days and while it's good to see one modeled to develop within the next few days i hope to see improvements in the pattern so that we really get one to remember.Currently the outlook is quite dry although of course quite a lot colder with perhaps a few areas seeing some flurries later.

For newbies the best easterlies show a better orientated Scandi high pointing ne/sw with some cold upper air coming around the base of the block and heading westwards across N.Europe towards the UK.The best 2 examples of this are from 1987/91

we can see that segments of the Siberian upper cold pool have broken off and forced westwards under the returning arm of the jet so an ideal orientation of the pattern for us.Indeed both setups brought the deep cold and widespread snow across many parts of the UK.

Now compare a couple of current charts UK-00z and GFS 06z for day 4 and we can see the differences

see the Siberian deep cold heading further south rather than west under the block.So in the short term we get a less deeper cold flow although of course still decent but for snow a colder incursion shown in the earlier examples create the instability and meaningfull snowfall.

Ok so the first stage is to get the easterly here which looking at the fax's and near term models is pretty much done and then let's hope for a better aligned high with time and deeper cold heading our way under the block.As long as the Atlantic is held at bay and we have continuing background signals for further amplification then this remains possible.

I think many of us after such a frustrating winter so far suffering cold and dry mid-latitude blocks would love to see this season finish with at least one widespread snowy spell.

Edited February 5, 2017 by phil nw.

[Frosty.]

19 minutes ago, BARRY said:

This is all hoping the GFS is right, it has so far this winter Been unreliable, where as the UKMO has the last laugh on all the models lets see what the UKMO has to say before we go predicting cold runs.

 

It's not just the Gfs / Gefs..it helps considerably to have the backing of the pros with their mogreps / GloSea5 seasonal models..it's looking very good I must say

[BARRY]

Just now, Frosty. said:

It's not just the Gfs / Gefs..it helps considerably to have the backing of the pros with their mogreps / GloSea5 seasonal models..it's looking very good I must say

Well here's to hoping we have across model agreement because it's along time coming 

[Frosty.]

1 minute ago, BARRY said:

Well here's to hoping we have across model agreement because it's along time coming 

I couldn't agree more, generally speaking the latest models look very encouraging for the majority on here who love cold weather with a chance of snow from the second half of the week ahead onwards..Bring It On! 

[Duane S.]

Before the 12z proper start to roll out. It may be worth remembering that it is macro differences in the longwave pattern (which is rapidly being firmed up upon) that are going to make the differences for what happens on the ground in the UK. And this will not be resolved today or any time soon. All we are seeing are differing outcomes in the Ops / ens.

Try to keep your toys in your prams, there will be plenty of runs to come which will show higher uppers than we'd like. Also, don't worry about the Azores High, that ought to end up being our friend, not foe. 1991 / 1996 both evolved in very similar ways and not doubt would have had this forum flapping in pretty much the same way as in recent days on here.

Let's just enjoy the ride because we don't even have a ticket to the raffle most winters!

Edited February 5, 2017 by s4lancia

[SMU]

The 12z is a nibble better alligned at 54 as well as the atlantic another 50-100 miles away from the North of ireland

we have x2 ways of getting deeper cold closer -

* better allignment

* bigger cold pool

I would suggest that the allignment wont correct a 'huge' amount ( scope 200 miles tops ) however again on the 12z the expanse of the area of lower heights ( remember the positive height bias ) means that the cold pool expanse is growing south - hence the -10c line is expanding south / south west with it....

S

 

[Hammer]

Noticed even at t66 the colder 850's a tad closer to East coast at same time frame to 6z

[Daniel*]

Surely that is unprecedented for the time of year? 

An abundance of  'warm' moist Tm air is going to fed up there due to our block in the coming days. It doesn't look good up there at all nonetheless we see our cold spell gain traction. 

Edited February 5, 2017 by Daniel*

[SMU]

Here we go folks - another upgrade coming- @72 & we have another 6 runs down to 36

expect the -10 line into London by T90...

[Duane S.]

3 minutes ago, Hammer said:

Noticed even at t66 the colder 850's a tad closer to East coast at same time frame to 6z

Yep, those small differences mentioned above by Steve are helping drag in colder 850s further west.

[Ice Day]

5 minutes ago, Steve Murr said:

Here we go folks - another upgrade coming- @72 & we have another 6 runs down to 36

expect the -10 line into London by T90...

Well the -11 into Norfolk at T78.  Everything further west again, could be another stonker coming up?

[Ali1977]

Looking better but what we need to prolong it and produce better convection related E flow, is to get the WAA that comes in around 144 from the West to cutting off the lump of LP to come in on a higher trajectory. At 144 on the last run it was into NW Scotland, the higher this is the better chance of holding back any NW feed and re-establishing a stronger high in a more favourable location

Edited February 5, 2017 by Ali1977

[That ECM]

How great to see this at T96! 

Edited February 5, 2017 by That ECM

[Man With Beard]

GFS 12Z - at T102, are there signs that the cold pool in the north sea is going to fuse with the depression sliding to the SW? If it does, we could see the whole cold pool dragged back south over the country. Snow would be likely!!

Edit: just missed!!

Edited February 5, 2017 by Man With Beard

[Duane S.]

Looks like the 12z GFS wants to deepen that low to our West a tad. Net effect that should keep it further north. Interested to see where we go from here with this playing out. Possibly a stronger initial easterly