Model output discussion pm 13/01/2016

[Mucka]

7 hours ago, jvenge said:

Hi Mucka. Did the 72-96 range settle down yet?

Hi, Not at all. Actually it is getting wilder

The phasing of the Azores low  with the Atlantic trough is almost upon us though so the output should begin to settle down though the next 24/48 hours.

It has been a long process, I first mentioned the Azores low was likely to influence our cold spell in some way back on Jan 6!

Since I first posted on the output potentially moving toward some trough disruption into NW Europe and cut off Iceland heights I think the output has shifted significantly in that direction though ultimately still with too much energy heading NE at the moment to sustain cold and snow prospects beyond the initial Atlantic incursion.

Overall we have seen any surviving amplification moved East which could keep things chilly at the surface for a day or two after the initial breakdown attempt but mix out the cold upper air so it will be difficult to get snow from the next Atlantic incursion.

I think we will get a breakdown but as that it will be inconclusive, I don't see zonal conditions returning and expect the pattern to reamplify a little further East again with possibly ridging into Scandinavia and a continued Southerly jet.

GFS 06z shows the ridge but below but I believe if we get this far we will the Atlantic digging South and not rolling over the top as ECM and GFS currently go for so I would expect to see a deeper and better defined Atlantic trough develop.

If the output goes that way then will start to see some Scandinavian high's being modeled again albeit my current thinking is an Easterly won't succeed and we wills see the focus of blocking for us once again switch to the Atlantic and possible Greenland high but that is light years away in model and forecast terms.

Back to the here and now and all of above could be irrelevant if this mornings UKMO is onto something because rather than show a trough held West and disrupt against a weakening ridge before pushing more energy NE it shows low pressure dive SE into NW Europe. I'm surprised nobody else seems to be taken by this output because it is potentially a game changer. Perhaps it is because it has no support from other models but if it repeats the dose this evening then cats and pigeons come to mind because that would hugely strengthen the prospects of a future Easterly setting up in the relatively near term IMO (say within 10 days) which would be an amazing turn around as it goes completely against current output and ensemble data. 

[Catacol]

3 hours ago, Steve Murr said:

All I would say about Stewarts forecast ( without being accused of trolling ) is both he & Tamara put a forecast out for 17 jan - end of jan delivering 1983 synotics + quote 'a classical -NAO showing' Yet no review on that ( or at least commentary on how that period is set to look ) just move onto the next projection of cold - with the caveat of 'strat allowing' - surely thats the caveat of the whole of the winter -

 

 

Yep - cant disagree with that Steve. The reference for a flip in the NAO to negative somewhere in the 23 - 27 Jan range was a clear feature, with the 1983 template of high pressure to north and a trough to the east. If this doesn't occur than the forecast will not be a fully successful one.... but note that 23rd Jan is still 8 days away and if you run the 1983 template from the archives there was actually a westerly phase in the days leading up to the flip in NAO. So if the cold does relax this week the forecast is not bust.... not until or unless we get to beyond Jan 27 and renewed northern blocking with a trough to our east doesn't arrive.

But in the end, bust or not, isn't forecasting what we are all trying to learn to do? If GP's forecast ends up off target in terms of that initial flip then so be it. We are still seeing some very exciting weather, some very exciting runs and to be honest no one can ever hope to be correct all of the time. It's all about probability... and I'm still seeing a higher than average probability of lowland cold and snow in the next few weeks for the south. Kudos to those who put their neck on the block and put together a serious forecast - much better than those of us unable or unwilling to do so.

[Methuselah]

Just a reminder ladies and genitalmens...please keep to discussing what the models are saying?

[SMU]

Will do Ed

although will reply to catacol on my post later.....

 

although will be late !

[Nouska]

2 hours ago, bobbydog said:

not necessarily the worst position for the vortex and at face value, you might even say thats a good chart-

31st Jan 1991...

We know that there was a strong SSW in the works at that time ....

Martineau animation:-     http://www.meteo.mcgill.ca/~pmartineau/updated_graphs/svw_anim/all_gif/1991_01_28

 The current projected strat profile - similar positioning of first warming but on a much weaker scale. There may be promise if it strengthens and upsets the current NH profile.

PS.  re your post of last night about my thoughts on expected weather patterns - haven't got a clue is the honest answer!

To clarify, there are so many unprecedented factors in current situation - years of studying analogues and corresponding weather patterns seem pretty futile in the face of it.

Edited January 15, 2016 by Nouska

[Swave Snow]

3 hours ago, TEITS said:

What concerns me is the models are consistently predicting a very positive NAO for the last week of Jan. Infact I would argue we are seeing more consistency in the model output in F.I than in the reliable timeframe. Like I said a few days ago, forecasts based on teleconnections mean sod all if this is not shown in the model output. I do not intend any disrespect to Tamara or GP but I do not have much faith in these forecasts.

With the utmost respect I can not see how you can say the above.  

The only consistency for over a week now is the inconsistency of the models to come to any agreement in FI or the usual reliable time period.

There should not be any concerns until there is agreement that holds together 

[Methuselah]

seems as though another reminder is required?? This is the Model Thread and is, believe it or not, the place for discussing the models' output. It ain't the place for knocking the UK MetO!

[bobbydog]

28 minutes ago, Nouska said:

We know that there was a strong SSW in the works at that time ....

Martineau animation:-     http://www.meteo.mcgill.ca/~pmartineau/updated_graphs/svw_anim/all_gif/1991_01_28

 The current projected strat profile - similar positioning of first warming but on a much weaker scale. There may be promise if it strengthens and upsets the current NH profile.

PS.  re your post of last night about my thoughts on expected weather patterns - haven't got a clue is the honest answer!

To clarify, there are so many unprecedented factors in current situation - years of studying analogues and corresponding weather patterns seem pretty futile in the face of it.

thanks nouska, that animation runs very quickly but as you say, it is in a similar position to the current strat. also worth noting (if i've interpreted the charts correctly) that the main warming happened at the turn of the month and the snow arrived only about a week later!

[ReindeerMarmalade]

5 minutes ago, Tim Brawn said:

cop out , they cant be wrong if they don't commit , they have said it might rain , it might snow , it might be cold , it might be less cold , all bases covered , suggest keep an eye on the radar and look out the window is the best option , woulod struggle to sell one of these weather computers on ebay at the moment

I rarely post in here but this is a perfect example of precisely why the MetO hedges its bets in situations like this. The models have been in turmoil recently, with at best unusual and at worst unprecedented conditions (in data terms) to try to sort through. Anyone who is literate and follows this thread will have noticed experienced posters commenting on how they've rarely (if ever) seen such outputs, and the models have struggled with internal consistency let alone cross-model agreement. I'm not entirely sure what you expect from MetO given the flip-flopping of the models...for them to pick a solution at random? Maybe resort to reading entrails or necromancy?

The idea that modelling chaotic systems is somehow 'easy' continues to perplex me, particularly when we're aware of the unusual conditions and ongoing flux. Of course, with access to at least some weather models anyone is able to have a crack at it themselves and show the MetO how it's done  

Head-bangingly frustrated as I am by the painful dearth of snow IMBY, I have to admit this has been (and is) a fascinating period for model-watching.

[Catacol]

1 hour ago, Tamara said:

 

It might be worth you going back and reading the posts that have been made, and represent what was actually said vs what is happening

 

 

Yes - rather important really.... You may be dubious as to the value of the longer range forecasting that goes on, but let's be absolutely clear what a forecast has said before calling it a bust. At the moment, as stated earlier, we are many days away from knowing.....

[Chris1986]

Next Alex update should be out in 20 min, will post here when released  

[Catacol]

2 hours ago, Steve Murr said:

 

* rain steaming in from the west - Turning to snow over the SW, wales, The midlands & NW before more than likely running out of juice - very similar to Feb 96.

 

Feb 96 had a bigger block to our east so the barrier the atlantic was sliding down against was rather more firm. But if we get anything close to Feb 96 next week I will be very happy. Most remarkable snow event in the south in my 32 years living in England....

[karlos1983]

2 minutes ago, Chris1986 said:

Next Alex update should be out in 20 min, will post here when released  

Edited January 15, 2016 by karlos1983

[Chris1986]

2 minutes ago, karlos1983 said:

Fingers crossed  Also should see the GFS throwing some runs out soon too, everyone's a winner!

[snowhope]

29 minutes ago, Tim Brawn said:

cop out , they cant be wrong if they don't commit , they have said it might rain , it might snow , it might be cold , it might be less cold , all bases covered , suggest keep an eye on the radar and look out the window is the best option , woulod struggle to sell one of these weather computers on ebay at the moment

This should tell you all you need to know though. The models as we have all seen in the past week or so are so volatile in their output, why would the MO/BBC commit? Millions of people rely on them for the forecasts! With the models in such a state of disagreement in the relative short term it would be a brave person to commit to a scenario on here let alone in the national Media.

[Chris1986]

Satellite and surface data indicate that Alex made landfall on the island of Terceira around 915 AM AST (1315 UTC) as a tropical storm with an intensity of 70 mph (110 km/h). At 1100 AM AST (1500 UTC), the center of Tropical Storm Alex was located near latitude 39.3 North, longitude 27.0 West. Alex is moving toward the north near 28 mph (44 km/h) and a turn toward the north-northwest and northwest is expected over the next day or so. Maximum sustained winds are near 70 mph (110 km/h) with higher gusts. Little change in strength is forecast during the next 48 hours. Alex is expected to lose tropical characteristics later today. Tropical storm force winds extend outward up to 460 miles (740 km) from the center. The estimated minimum central pressure is 986 mb (29.12 inches). 

 

Courtesy of National Hurricane Centre

 

Edited January 15, 2016 by Chris1986
source added

[Jason M]

38 minutes ago, Swave Snow said:

With the utmost respect I can not see how you can say the above.  

The only consistency for over a week now is the inconsistency of the models to come to any agreement in FI or the usual reliable time period.

There should not be any concerns until there is agreement that holds together 

On the contrary , there has been very good agreement regarding the medium to longer term output, which has been to rebuild Euro heights. It doesn't mean it will happen of course but it is what has (and still is) been showing. 

If an easterly was being shown with the same consistency the forum wouldn't be ignoring it. Its one of those situations where the shorter term prognosis in our part of the world is a bit uncertain but the models agree largely on the destination. As said above, no guarantees that the end result will be what's shown, but it must be seen as the hot fav at present (sadly!!).

 

[Starsail]

The last few pages of this thread is what makes this forum so amazing. The big hitters, Tamara, GP, Steve murr and a few others rolling their sleeves up and debating to such a high level with their considerable intellect and expertise.

We can't guarantee the snow but  sit down with a cup of coffee and you can guarantee a first class read.

[Interitus]

1 hour ago, Nouska said:

We know that there was a strong SSW in the works at that time ....

Martineau animation:-     http://www.meteo.mcgill.ca/~pmartineau/updated_graphs/svw_anim/all_gif/1991_01_28

 The current projected strat profile - similar positioning of first warming but on a much weaker scale. There may be promise if it strengthens and upsets the current NH profile.

PS.  re your post of last night about my thoughts on expected weather patterns - haven't got a clue is the honest answer!

To clarify, there are so many unprecedented factors in current situation - years of studying analogues and corresponding weather patterns seem pretty futile in the face of it.

No SSW, there was not a wind reversal at 10mb 60°N lol

[IDO]

Unusual for Dr Cohen to be so downbeat:

 

 

It appears that there is still no clear sign from GFS (refers to) of a SSW though he believes it cannot be ruled out. I suppose we are mid-Jan and no forecast for an SSW is getting into the reliable. We are obviously running out of time given the usual lag time. Lets hope the AAM torpedo resets the UK sector with a decent Winter pattern as a strat event is not likely in the next 4 weeks.

[bobbydog]

5 minutes ago, Interitus said:

No SSW, there was not a wind reversal at 10mb 60°N lol

interesting.... even better then really, if feb 1991 occurred with a warming rather than an SSW...

[mountain shadow]

5 minutes ago, IDO said:

Unusual for Dr Cohen to be so downbeat:

 

 

It appears that there is still no clear sign from GFS (refers to) of a SSW though he believes it cannot be ruled out. I suppose we are mid-Jan and no forecast for an SSW is getting into the reliable. We are obviously running out of time given the usual lag time. Lets hope the AAM torpedo resets the UK sector with a decent Winter pattern as a strat event is not likely in the next 4 weeks.

Reading behind the lines in Strat thread there has been a general downbeat on the lack of an SSW being modelled.  It's not going to happen for Winter now. 

However a decent displacement of PV could still result in a cold period and this current snap has occurred with a deeply cold strat vortex.

[Rocheydub]

5 minutes ago, mountain shadow said:

Reading behind the lines in Strat thread there has been a general downbeat on the lack of an SSW being modelled.  It's not going to happen for Winter now. 

However a decent displacement of PV could still result in a cold period and this current snap has occurred with a deeply cold strat vortex.

Yep, agree strongly, unless we can grasp something trop lead. Maybe Alex will trigger something off as it is so unusual. Not to discount a SSW happening at all, just looking less likely. I will of course bow to recretos and chiono et al if they differ with me, just my understanding.

[Nouska]

10 minutes ago, bobbydog said:

interesting.... even better then really, if feb 1991 occurred with a warming rather than an SSW...

I think that was a reference to a conversation in the Strat thread ....

Look at the table on the Berlin site - asterisk denotes SSW in February 1991.

http://www.geo.fu-berlin.de/en/met/ag/strat/produkte/northpole/index.html

[Day 10]

Slightly better early on