Model output discussion - 5th December 2016 - Into Winter we go

[blizzard81]

6 minutes ago, snowray said:

Only one member but if this is a new trend its got to start somewhere. All eyes on the 00z could be a big one, ECM needs to smell the coffee tomorrow.

The ecm ensembles have already had a sip

[Man With Beard]

3 minutes ago, karlos1983 said:

What about the mighty BOM

Can't see the BOM but the FIN and NASA disrupt too

Edit: not in a way that brings an easterly, just to be clear!

Edited December 10, 2016 by Man With Beard

[Mucka]

Netweather will be gathering a choir made from members to sing the forums version of 12 days of Christmas. (in this case 7 days)

 

On the first day of Christmas

my true love said to me:

A cold long fetch Easterly 

 

On the second day of Christmas

my true love said to me:

Two undercuts 

and a cold long fetch Easterly

 

On the third day of Christmas

my true love said to me:

Three channel lows 

Two undercuts 

and a cold long fetch Easterly 

 

On the fourth day of Christmas

my true love said to me:

Four whiteouts 

Three channel lows 

Two undercuts 

and a cold long fetch Easterly 

 

On the fifth day of Christmas

my true love said to me:

Five snow ploughs 

Four whiteouts 

Three channel lows 

Two undercuts 

and a cold long fetch Easterly 

 

On the sixth day of Christmas

my true love said to me:

Six wild goose chases 

Five snow ploughs 

Four whiteouts 

Three channel lows 

Two undercuts 

and a cold long fetch Easterly 

 

On the seventh day of Christmas

my true love said to me:

Seven swans a skating 

Six wild goose chases 

Five snow ploughs 

Four whiteouts 

Three channel lows 

Two undercuts 

and a cold long fetch Easterly 

 

 

 

[karlos1983]

5 minutes ago, feb1991blizzard said:

I think the MOGREPS updates 4 times a  day!!!

Oh, good Job I'm not a wiki data finder inputter 

I think next time I'll just let Ian reply lol 

Edited December 10, 2016 by karlos1983

[blizzard81]

3 minutes ago, Man With Beard said:

Now I've just shocked myself - I've just checked every op run - GFS, ECM, JMA, GEM, NAVGEM, ARPEGE, UKMO - and apart from the UKMO they ALL show trough disruption against the block.

That means the GFS 18Z idea is not in the slightest an outlandish one. Indeed, the JMA has arguably a better Scandi high on it. And the UKMO may disrupt later on, maybe?

It will be entirely about how far heights can push north into Scandi. There's a real chance!

 

The 168hr ukmo chart kindly posted by corinthian earlier possibly showed the best trough disruption of all today's models

[chris pawsey]

4 minutes ago, Man With Beard said:

Now I've just shocked myself - I've just checked every op run - GFS, ECM, JMA, GEM, NAVGEM, ARPEGE, UKMO - and apart from the UKMO they ALL show trough disruption against the block.

That means the GFS 18Z idea is not in the slightest an outlandish one. Indeed, the JMA has arguably a better Scandi high on it. And the UKMO may disrupt later on, maybe?

It will be entirely about how far heights can push north into Scandi. There's a real chance!

 

There is a chance, we just have to hope the trend is picked up. Glosea5 still maintains the blocked last week's of Dec, let's hope the other models jump on board the polar express  (not daily express!!). Let the GFS lead the way... can't believe I said that!! There is hope coldies!!

[feb1991blizzard]

2 minutes ago, karlos1983 said:

Oh, good Job I'm not a wiki data inputter 

Theres actually 2 different runs of the MOGREPS - the UK run and the global run, each run 4 times a day.

http://www.metoffice.gov.uk/research/modelling-systems/unified-model/weather-forecasting

[blizzard81]

The 10th Dec is going to be one of the most important days of model outputs this winter for the UK. The 00z suite is crucial. That scandi high needs to gain traction over the next 24 hours.

[snowray]

5 minutes ago, Mucka said:

Netweather will be gathering a choir made from members to sing the forums version of 12 days of Christmas. (in this case 7 days)

 

On the first day of Christmas

my true love said to me:

A cold long fetch Easterly 

 

On the second day of Christmas

my true love said to me:

Two undercuts 

and a cold long fetch Easterly

 

On the third day of Christmas

my true love said to me:

Three channel lows 

Two undercuts 

and a cold long fetch Easterly 

 

On the fourth day of Christmas

my true love said to me:

Four whiteouts 

Three channel lows 

Two undercuts 

and a cold long fetch Easterly 

 

On the fifth day of Christmas

my true love said to me:

Five snow ploughs 

Four whiteouts 

Three channel lows 

Two undercuts 

and a cold long fetch Easterly 

 

On the sixth day of Christmas

my true love said to me:

Six wild goose chases 

Five snow ploughs 

Four whiteouts 

Three channel lows 

Two undercuts 

and a cold long fetch Easterly 

 

On the seventh day of Christmas

my true love said to me:

Seven swans a skating 

Six wild goose chases 

Five snow ploughs 

Four whiteouts 

Three channel lows 

Two undercuts 

and a cold long fetch Easterly 

 

 

 

Thats brilliant Mucka...wheres frosty btw? he'd love that!

[johnny1972]

2 hours ago, damianslaw said:

Some good posts in the past 30 minutes, yes eyes on whether we see a more sharpened trough feature exiting the NE USA seaboard at the 144hrs, which will induce a more pronounced amplified low, allowing the ridge to our east to become more north-south aligned rather than east-west aligned which in turn would force the jetstream on a more NE path, meaning the current progged deep low shown on today's models rather than taking a more east-west path, will be forced NE, and crucially enable heights to build in more strongly from the SE aided by the azores high which will be able to ridge north as well.

I'm not seeing an easy ride for the atlantic zonal train, the ridge to the east looks a strong feature. In time it could very easily anchor itself into a position that enable the UK to sit on the colder side of the jet, before December is out.

I suspect the models will be painting a very different outlook 240 hr timeframe this time next week than they are now.

Damian 

I have read with interest the posts and charts since November. The charts presently scream 2015 all over again going forward with an endless SW flow and BBQ's coming back out. I completely respect all the work done and continuing to be done by the knowledgeable on here and we all know who they are.

I know there are many signals for the global pattern but I have noticed (correct me if I'm wrong) that the power in the jet stream has coincided with the vortex setting up shop in the Canadian sector which is interacting with the warm waters off the Newfoundland area thus creating a steep temp gradient. The same SST pattern was prevalent last year. In 2010 it was the opposite with cold water off Newfoundland and warm waters much further south.

could it be that it is really much simpler at present to look in this area as IMHO the interaction of the vortex with the much warmer SST's are driving our weather patterns here in the U.K. and NW Europe.

I am a coldy through and through but although there definitely are different signals this year they clearly aren't affecting the pattern as much as thought.

Views?

[nick sussex]

1 minute ago, blizzard81 said:

The 10th Dec is going to be one of the most important days of model outputs this winter for the UK. The 00z suite is crucial. That scandi high needs to gain traction over the next 24 hours.

I'll be viewing the outputs from behind the sofa tomorrow! It won't be a case of looking well into FI as we have done for signs of hope. Given the set up and the very fine margins my newly designed EEPPS( early exit poll projection system) could well call the Scandi high election by as early as T96hrs or even a bit earlier! It really is that dependent on events within that timeframe.  By latest T96hrs we'd have a good idea of the upstream pattern and whether the trigger shortwave is favourable. As much as I'd like to be up that early to watch the drama of the GFS 00hrs run unfortunately being a bit of a night owl means I'm usually only just turning in by around 2am !

[Ali1977]

Wow, disappeared for the evening and come back to 8 new pages - I knew that meant one thing...winter is back on the cards , great reading all the posts in one go that slowly got better and better...big day tomorrow .

GLOSEA could have called this correct, lets hope so. 

Edited December 10, 2016 by Ali1977

[Catacol]

Signs now of the blocking pattern becoming more favourable. Be in no doubt - we are in a very blocked atlantic pattern, and so far a very dry season as a result. 

3 key observations tonight. Firstly MJO forecast solid. Clear shift towards 6-7-8 with no sign yet on any spoilers in the Indian Ocean.

Secondly the vortex shape is also coming good. From 30hpa down to 70hpa a clear twin lobe shape forming, with consequent space for height rises to our north. 70hpa diagramme for the start of Xmas week below:

But finally important to note the ongoing GEFS forecast for the GWO. This is our ENSO disconnect condition and we dont really want to see it dropping through a 1 - 3 orbit. The current forecast is set to do exactly this, but it has been one of the ongoing peculiarities of the season so far - the fact that the ENSO suggests a drop into 1 - 3 but the atmosphere refuses to follow suit. Forecast below - but evidence of the last few weeks is that the forecast may well continue to be off target. Is this what is causing such strange behaviour from the models in not picking up the signal that the big long rangers such as GLOSEA are seeing? Is that signal about to win out?

Conclusion: the days of mild coming to an end as we return to a more neutral temperature profile and then look to see the block extend to the north. Modelling says NE. GP says NW. Frankly after the comments and depression on this thread over the last few days all I'm looking for is a movement north first of all. If that can happen then we can worry about the details later. Gut feeling of weeks ago that winter would start from approximately mid month - perhaps now last third - still a definite possibility.

Edited December 10, 2016 by Catacol

[blizzard81]

27 minutes ago, nick sussex said:

I'll be viewing the outputs from behind the sofa tomorrow! It won't be a case of looking well into FI as we have done for signs of hope. Given the set up and the very fine margins my newly designed EEPPS( early exit poll projection system) could well call the Scandi high election by as early as T96hrs or even a bit earlier! It really is that dependent on events within that timeframe.  By latest T96hrs we'd have a good idea of the upstream pattern and whether the trigger shortwave is favourable. As much as I'd like to be up that early to watch the drama of the GFS 00hrs run unfortunately being a bit of a night owl means I'm usually only just turning in by around 2am !

Same here Nick, especially on a weekend Will take my first nervous peak around 9am lol. Fingers crossed for something winterlike!

[Mucka]

Edit.

Just in case people are wondering why these early morning posts look a little odd it is because I do a running commentary with my thoughts as the run comes out and then edit in the next thought etc.

Never thought to mention that before.

 

GFS 00z good continuity with 18z with marginal improvements early

Jet profiles 144 00z/18z comparison.

leading to a sniff of undercut at 144 and the pattern upstream is also slightly more amplified.

Only negative is the jet is a little more powerful

My bones tell me that any Easterly is a red herring and it will be the Atlantic we will eventually look to for blocking be it a retrogressing pattern or Atlantic ridge - but then bones aren't very scientific.

 

Quite a few changes upstream to recent output on this run though and the PV not looking very organised.

 

By day 10 things look quite different to the 18z with blocking in control and potential for retrogression.

 

Edit

Well that escalated quickly

Good ol' GFS FI.

Other than GFS FI Atlantic hurricanes though two things of note

First decent continuity with 18z for better amplification and potentially better blocking say 72 through 120.

Secondly the huge changes upsteam which suggest the output could still be quite volatile through early FI

 

Edited December 10, 2016 by Mucka

[Mucka]

GFS ensembles.

Looks like our friend Shannon is back to haunt the models. Quite high divergence between ensemble members by 144,

Examples.

[AWD]

Suprised you haven't mentioned the UKMO 0z yet Mucka?

 I

Ideally, we would like the high a little further north over Lapland, but the intriguing prospect I see there is an attempt to send energy underneath and cut the high off.

[knocker]

Today

South Wales, south west and southern England will be cloudy with rain tracking east, which will be heavy at times, clearing the SE by this evening. Remaining mild.

So on to the GFS this morning and as usual restricting this to the next ten days. The long wave pattern is essentially the same but with more amplification and some new adjustments vis the trough and HP towards the end there is a continued move towards a more blocked scenario. The last couple of runs briefly indicated a plausible and quick route to cold by having the very strong NE jet disconnect the ridge and channel energy on a diverse path SE and feed a cut off low to the SE. This is now off the table but is replaced by probably a more likely, and interesting development. But to start a little earlier.

To start the week we have a ridge over the UK with the main upper trough out west. A small low breaks off from this and tracks SE, disrupting the ridge and bringing unsettled and showery conditions to all of the UK on Tuesday. From here the familiar story of the next upper trough tracking east whilst pushing the HP so that by T144 the next low is over Iceland with the associated trough running south west of Ireland with the surface fronts a little further east over Ireland.

From here the fun and games begin in earnest. Much amplification takes place as the trough rapidly deconstructs and the Azores HP surges north east and we actually end up with Rex Block at T204.

From here the HP moves east to be centred over Denmark whilst out west a large, complex, negatively tilted upper trough is orientated NE Canada to Iberia leaving a lot of surface lows dotted about. After that it's a raging battle between the big beasts but best left for another day.

So a quick summation weather wise.

After some showery outbreaks Tues/Weds the next frontal system hits the block on Friday and fizzles out and thereafter dry as an easterly component becomes established. Temps above average to begin with and becoming cooler in the easterly regime.

Edited December 10, 2016 by knocker

[Mucka]

8 minutes ago, AWD said:

Suprised you haven't mentioned the UKMO 0z yet Mucka?

 I

Ideally, we would like the high a little further north over Lapland, but the intriguing prospect I see there is an attempt to send energy underneath and cut the high off.

 

I guess I'm just not seeing signs of the trough disruption necessary to get the undercut we need.

It is encouraging the more pattern backs West and the stronger the block though.

BREAKING NEWS

The signal for Northern blocking in GFS ensembles in run up to Christmas is strengthening.

 

 

[ArHu3]

It's nice to suddenly see winter come this close and that I was right: winter doesn't show up in FI and then moves forward, no it suddenly appears between 144-192h and amplifies on the next few runs ;p

[knocker]

2 minutes ago, ArHu3 said:

It's nice to suddenly see winter come this close and that I was right: winter doesn't show up in FI and then moves forward, no it suddenly appears between 144-192h and amplifies on the next few runs ;p

I assume you talking about Kiev?

[ArHu3]

4 minutes ago, knocker said:

I assume you talking about Kiev?

Almost there, for me  but I also noticed that GFS has a tendency to be much too underestimate the cold on the t2m, even at the +6h, sometimes by as much as 4-5 degrees!

[Seasonality]

8 minutes ago, knocker said:

I assume you talking about Kiev?

And half of Europe knocker. 00z not as extreme but I would say it shows a colder evolution is possible. The two lobes of the vortex are like a butterfly on the 00z.

[Ali1977]

ECM quite flat at day 7, the morning runs haven't built on those from last night showing blocking or Atleast holding the high over Central Europe giving us a SEly feed. Can't say I'm surprised.

Nice high in place later on, and it would be a pretty chilly one I reckon.

Edited December 10, 2016 by Ali1977

[knocker]

47 minutes ago, ArHu3 said:

Almost there, for me  but I also noticed that GFS has a tendency to be much too underestimate the cold on the t2m, even at the +6h, sometimes by as much as 4-5 degrees!

 

Well we can always switch to 850mb temps and the Black Sea coasts