Model output discussion - 1st December onwards

[chris55]

ECM debit also with a colder cluster still apparent. Op in the middle.

 

[shaky]

Gfs pretty much the same as 00z after an improvement of sorts at 90 hours!!!the de bilt ensembles look delicious!!!there is more colder runs than mild ones!!could we see a ecm special tonight!!

[blizzard81]

2 minutes ago, shaky said:

Gfs pretty much the same as 00z after an improvement of sorts at 90 hours!!!the de bilt ensembles look delicious!!!there is more colder runs than mild ones!!could we see a ecm special tonight!!

I hate to say it but I am certain the opposite will happen. The op with it's higher resolution will lead the way and therefore I expect the colder ensembles to lift out this evening.

[Nick F]

43 minutes ago, blizzard81 said:

As long as they undercut, otherwise it's just more wet, stormy weather. This is what I fear as heights remain relatively high over southern europe.

Well this the risk we face with the current pattern, a continuous feed of lows from the Atlantic directed at the UK and a block to the east with NWP not really taking these lows far enough south to spare northern and western Britain from more flooding misery, because the block is drifting away from us.

The block to our east has not developed through the usual route, IMO,  to bring us sustained cold and wintry weather from the east. The usual empirical route to a cold easterly would be either: a Scandi high to develop from a ridge of high pressure building NE over the UK pushing a cold pool S then SW across NW Russia then west across Europe, with Atlantic lows then merging with low heights/pressure over Europe; or, an upper vortex breaks away SE from Greenland into northern then Central Europe with Arctic high pressure over Svalbard area bridging with high pressure building in behind from the N Atlantic witn blocking to our north.

The current / near term block develops from a ridge north to our east ahead of low pressure close to western UK ... a higher risk strategy in my view to get a cold enough easterly flow across all the UK for snow with such a vigorous Atlantic flow against a block receding to the east.

Longer term prospects still looking good though, with the signal for plenty of high latitude blocking, we just need to wait for the Atlantic to weaken and the flow to become more convoluted upstream.

Edited December 29, 2015 by Nick F

[Chris K]

6 minutes ago, shaky said:

Gfs pretty much the same as 00z after an improvement of sorts at 90 hours!!!the de bilt ensembles look delicious!!!there is more colder runs than mild ones!!could we see a ecm special tonight!!

Sorry shaky I'm not as confident as you. All I've seen the past couple of days is the UK being stuck with further wet and windy weather with the block only causing rain to stall over us instead of sweeping through.

Every time the real cold air is about to touch our shores it gets shunted away again by repeating LP systems pushing in.

I am aware the cooler uppers may mean some snow for higher levels, but for the majority its wet and windy. I'm just hoping a more favourable pattern sets in longer term.

[winterof79]

18 minutes ago, chris55 said:

ECM debit also with a colder cluster still apparent. Op in the middle.

 

Morning Chris,could you provide a link for those as I appear to have a glitch on my previous link.

[snowangel32]

Knife edge stuff who needs Christmas TV when we have netweather today has been a mixed bag the gfs has moved towards the UKMO but on the other side the Ecm has moved towards the gfs outcome, those dam pesky short waves . But with the models chopping and changing almost every run even in the reliable time frame and the mixed background signals this could go either way still as the ensembles demonstrate. Very interesting times ahead though but I say that with a heavy hart because we can all agree there is further rain and wind coming to areas that just can't  cope at the moment. 

[mulzy]

16 minutes ago, shaky said:

Gfs pretty much the same as 00z after an improvement of sorts at 90 hours!!!the de bilt ensembles look delicious!!!there is more colder runs than mild ones!!could we see a ecm special tonight!!

That's De Bilt.  UK ensembles will probably not look that good.  I think confidence is growing for a wet spell into the New Year for most (with snow on high ground in the North).  Think we'll have to be honest and say we're losing this one.  Still time for a change and lots of potential later so not all doom and gloom...

Edited December 29, 2015 by mulzy

[mountain shadow]

4 hours ago, mulzy said:

Think we'll have to be honest and say we're losing this one.  

I don't think there was any real support for a cold Easterly.  There was the occasional run showing great potential which was ramped up.

The Met Office were never on board and have once again shown their prowess. 

Still things look promising for later in the Winter.

[mb018538]

I agree, to me the colder clusters were outweighed by the not so cold ones....it looks horrendous from here. A huge block stopping all those Atlantic lows going anywhere, so we're stuck right under the trough with copious rainfall again and gale force winds. Yuck!!!

[MPG]

1 minute ago, mb018538 said:

I agree, to me the colder clusters were outweighed by the not so cold ones....it looks horrendous from here. A huge block stopping all those Atlantic lows going anywhere, so we're stuck right under the trough with copious rainfall again and gale force winds. Yuck!!!

Give me a Greenland high any day over a Scandi block.

[blizzard81]

Just now, mb018538 said:

I agree, to me the colder clusters were outweighed by the not so cold ones....it looks horrendous from here. A huge block stopping all those Atlantic lows going anywhere, so we're stuck right under the trough with copious rainfall again and gale force winds. Yuck!!!

I must say that I am gutted with the latest outputs, the last thing this country needs at the moment is more heavy rainfall. I really do feel for all those affected by this atrocious weather.

[David Morse]

The latest GFS looks very confident that the cold air encroaching from the east will be easily displaced. Would it be correct to say that the GFS always underestimates how hard it is for cold blocking to be moved out of the way with a return to more zonal conditions? I remember in 2010 that the GFS kept predicting the end of the cold only to have to back track in later runs and try again, but the block remained! Probably because very cold air at the surface under cuts the encroaching warm Atlantic air and it just stays put?

[blizzard81]

2 minutes ago, David Morse said:

The latest GFS looks very confident that the cold air encroaching from the east will be easily displaced. Would it be correct to say that the GFS always underestimates how hard it is for cold blocking to be moved out of the way with a return to more zonal conditions? I remember in 2010 that the GFS kept predicting the end of the cold only to have to back track in later runs and try again, but the block remained! Probably because very cold air at the surface under cuts the encroaching warm Atlantic air and it just stays put?

I think the jet has let us down here. We needed it to be on a more southerly trajectory. We would probably have hit the jackpot then.

[knocker]

Apparently divergent outflow emanating from the winter storms in the US is helping to tighten PV gradient over eastern Canada & amplifying the jet exiting the same. To my simplistic mind this will increase energy transfer over the UK and be bad news vis wet and windy as LP systems run ENE,

[NO LONGER POSTING]

1 minute ago, knocker said:

Apparently divergent outflow emanating from the winter storms in the US is helping to tighten PV gradient over eastern Canada & amplifying the jet exiting the same. To my simplistic mind this will increase energy transfer over the UK and be bad news vis wet and windy as LP systems run ENE,

Me and another cant remember who were talking about this at the beginning of December the GFS was picking up on strengthening the jet towards the end of December, but then the charts removed it..

[chris55]

37 minutes ago, winterof79 said:

Morning Chris,could you provide a link for those as I appear to have a glitch on my previous link.

 

http://www.knmi.nl/nederland-nu/weer/waarschuwingen-en-verwachtingen/ensemble-verwachting-detail

 

Mine went strange as well. Looks like it's now mobile friendly. 

[blizzard81]

1 minute ago, knocker said:

Apparently divergent outflow emanating from the winter storms in the US is helping to tighten PV gradient over eastern Canada & amplifying the jet exiting the same. To my simplistic mind this will increase energy transfer over the UK and be bad news vis wet and windy as LP systems run ENE,

To my even more simplistic mind, I haven't got a clue what that means for the UK. I thought anything to do with amplification would be good news for us? 

[Nick F]

At least we eventually get salvation from 06z GFS  with regards to mid Atlantic and Greenland height rises as the Atlantic vortex merges with the cold pool over Scandi ... This a much better route for sustained cold from the N and NE.

[knocker]

1 minute ago, blizzard81 said:

To my even more simplistic mind, I haven't got a clue what that means for the UK. I thought anything to do with amplification would be good news for us? 

The jet would be an exception.

[Snowman.]

5 minutes ago, blizzard81 said:

To my even more simplistic mind, I haven't got a clue what that means for the UK. I thought anything to do with amplification would be good news for us? 

There is never a guarantee of cold even an SSW doesn't guarantee cold.  

[damianslaw]

More topsy turvy twists and turns to come from the models in the days ahead - the general theme is for a colder episode as we enter the New Year compared to recent weeks (temps around normal mind, but a bit below in the north increasing the likelihood of snow down to low levels over northern half of the country, the Scottish Ski resorts will be very pleased with the outlook - copious snowfall and plenty of freeze slight thaw action).

Importantly all the models are maintaining a weak build of heights to our north which will keep the jet on a more southerly track, and help aid foundations for something perhaps substantially colder as we move further into January.

The most likely pattern is quite a complicated one - heights remaining strong over western Russia but relinquishing heir grip over scandi, allowing the atlantic trough to edge far enough eastwards to pull down a potent PM blast later next week and more importantly allowing mid atlantic height rises to develop. A push of mid atlantic heights towards Greenland linking up with the strong heights to our NE is the most likely way to a cold spell setting in as we enter the middle of next month.

[David Morse]

The jet is strong in the latest 06z GFS run, but its showing a divergence to the south at 90 hours which remains so well into FI. In North America there has seen a recent change to cold in the south from a very mild winter so far (t-shirt weather in Atlanta on xmas day at 71F) this is at odds to what a normal El Nino winter should be with nominally warmer to the north and colder to the south which should weaken the jet? I wonder if this change will see a weakening of the jet now?

[MR EXTREMES]

16 minutes ago, Nick F said:

At least we eventually get salvation from 06z GFS  with regards to mid Atlantic and Greenland height rises as the Atlantic vortex merges with the cold pool over Scandi ... This a much better route for sustained cold from the N and NE.

Certainly is a possibility.

minor exiting of systems from the northern parts of the states can turn things and be major game changers if cold is what is wanted.

can also work the opposite way but removing heights from our southwest or south out of Europe is a big part of the jigsaw as for knockers hunt for a northerly tracking jet this will become a distant memory as and when the vortex comes to Scandinavia side.

but in all honesty in the next few days I see the building blocks towards cold gathering pace mjo phase 8 yes please.

the models have been very good to pick up although finer details are always troublesome regardless which model.

cant wait for the 12z

although easterly may not be incoming still cold enough from the west or northwest for some disruptive white stuff.

although I must admit I feel for those who are suffering yet another winter of discontent so my heart goes out to them.

[Cloud 10]

1 hour ago, Weathizard said:

A quite massive difference between that and the 00z GFS ensemble suite mean, surprising for two ensemble suites to be so different, shows the volatility of the situation I guess.

 

 

 

Ensemble mean a bit colder on the 06z.