Model Output Discussions 06z 04/11/16

[karlos1983]

4 minutes ago, nick sussex said:

Given where we were yesterday and the huge changes especially in the UKMO output we've at least reached base camp!

Where we go from here depends on how much energy can disrupt off the troughing to the west, we don't want to see the bowling ball low as per the UKMO T144hrs output.

You preferably want the weaker shortwave as shown in the GFS, we still don't manage to get those lower heights far enough east towards northern Italy. That's really what we need to see going forward.

Yep, that's really all I was saying. I wasn't insinuating that we are staring down the barrel of a deep cold outbreak from the north or east. But to win the lottery you need a ticket. I'd say we've just got to the shop and are standing in the que right now. Whereas yesterday we had got to the shop at 7:45 and it was to late!

Edited November 26, 2016 by karlos1983

[SMU]

22 minutes ago, IDO said:

Not really seeing anything unusually cold in the next 7 days. The trend looks to push the cold upper flow too far east for snow (nominal chance now) and still a small chance of a dry northerly. The high has been consistently modelled to sink SE and in this run it does. That high is not going to just sit there IMO as the models are not even entertaining that. The Azores then pushes in bringing milder air from around D9.

I see no upstream amplification to stop the mobility of the flow and there is absolutely no WAA worth its salt other than transient topplers other than to ML's. Very little potential showing up in the runs and unless the models flip soon its wait it out till mid-Dec.

At around D9 on the GEM and GEFS: 

Mild more likely in the mid term with 14c after D10 possible with that Azores push.

We have a PV in disarray and there is just no forcing to take advantage of this, even if its just Rossby wave action to kick the strat PV; really a missed opportunity despite the potential further down the line. Thankfully the trop PV still showing no trend to regroup so maybe in a couple of weeks we will get some forcing but certainly zero consistent cold runs coming from the GFS and that is not good when so much is in our favour.

In the current position which is a possible transitional one in the mid term- pointless looking past day 7 TBH let alone forecasting 14c after day 10..

Also in just 2 runs the GFS ENS ( now 12z) have totally changed the atlantic profile at 120 from a positive tilted NE jet flow to a blocked neg tilt...

S

[Captain Shortwave]

A lot of interesting output to take in, but perhaps again it is best to compared the same initialised run between today and yesterday.

Yesterdays UKMO 12z (Day 6) vs todays (Day 5)

   

That is quite a difference with yesterdays output suggesting an increase in temperatures and the threat of wind and rain for northern and western areas, today we see low pressure becoming slow moving in the western Atlantic with the UK ridge slowly sheering away as the milder 850s get mixed out and more importantly warm air pushes north west. The result is an increasingly chilly outlook albeit still dry with potentially some hard frosts developing after midweek. 

The same with the GFS

   

The key again is the much deeper Atlantic trough which is aligned in a similar manner to UKMO which differs from yesterday with that rather strong Azores/UK high with milder air trying to force its way NE.

Funny old thing watching the models, we have actually seen a full swing to the ECM's idea of really developing that low upstream but have suddenly found another route to develop a more amplified pattern from the starting position of some of those grotty ECM operationals over the past couple of days.

Do not rule anything out, but I remain more convinced of conditions being settled and chilly with milder weather being limited in scope, whether we can get a proper cold/wintry spell remains to be seen but I don't see a proper westerly set up occurred in the near future. Anyway no point trying to predict a week in advance as by the charts above the models are currently either very wrong at 5/6 days out anyway.

Edited November 26, 2016 by Captain Shortwave

[OldMetMan]

On 11/21/2016 at 14:55, Summer Sun said:

@OldMetMan is still around he last visited on Thursday

https://www.netweather.tv/forum/profile/13989-oldmetman/

Yes I'm still here, just too busy with work and the like. I appreciate the kind comments though, thank you all.

This autumn/early winter looks so different compared to recent years, I am impressed by the significant temperature fluctuations up in the stratosphere, not to mention the relative weakness of the Atlantic systems coming our way (apart from Storm Angus of course). I note that quite regularly in runs over the last week or two the GFS has shown a real wintry setup in the longer term, with the jet travelling way south. 

There's quite an arctic plunge heading into W Europe in the next few days, bit too far E for our purposes but if HP stays anchored close to us and LP going over the top, further incursions of cold air seem likely very near to us. I'm looking for signs of cold air pooling over Europe in the coming days. There has already been very intense HP last week in Russia (near to 1070mb) so if the cold air gets a real chance to settle over Europe, I think it would only be a matter of time before it spreads our way.

I've a feeling in my old bones that the weather might make headlines this winter and not from rain, wind and floods as has happened so much in recent years, but "The Big Freeze" type story. I think a really cold winter is well overdue (the last one that I think qualifies as that was 1978/79). I've even beefed up my home heating in preparation! 

If I see anything I think looks promising in the coming days, I'll be back!

 

[phil nw.]

Certainly comparing both todays 12z runs with yesterdays and looking at the same date-01/12/16 both on the UK and GFS we see better Atlantic ridging.

So on the left day 6(yesterday) and day 5(today) on the right

a sharper and better ridging nw up towards Greenland and a more negatively tilted pattern indicating less forcing from the northern jet.Note too the Newfoundland trough heading further south east underlining a better split in the jet with more energy heading south.

Another switch like this tomorrow and it could well change the later pattern.

It will interesting to see what the ECM makes of it all later.

Note-I see the captain got there first -anyway here's the NH view,lol

Edited November 26, 2016 by phil nw.

[blizzard81]

48 minutes ago, Banbury said:

Just looking at what the charts are churning out they seem to show something different to what N Miller has just said

 " as the week goes on it will turn less cold "  I know these charts aren't that great BUT

Also the UKMO 12z run would suggest some chilly days ,  today has been 9c , seems an odd comment from Nicky boy

Either the models are all wrong at T120 or the bbc forecasts are using old data. It really is that simple.

[northwestsnow]

Its complicated, where i do agree with IDO is the repeating signal to sink the high, the natural upstream  response to that would be the PV gathering strength- thats not a pattern coldies want to see - ecm will be interesting...

[nick sussex]

Lets hope that after this move to the ECM it then doesn't go AWOL! I tend to think that its on the money here because the GFS and UKMO have been woeful in the last few weeks and its like picking the form team in football. Of course as we've seen form teams can score the odd own goal but with the ECM latching onto this trend within the T144hrs mark and with others supporting that now I would be gobsmacked if it hoofed the penalty over the bar.

The issue if lets say the ECM continues with the same trend is to get the cold air west rather than doing its skirting routine avoiding the UK and heading se and we still need some changes to get to that point.

[IDO]

21 minutes ago, Steve Murr said:

In the current position which is a possible transitional one in the mid term- pointless looking past day 7 TBH let alone forecasting 14c after day 10..

Also in just 2 runs the GFS ENS ( now 12z) have totally changed the atlantic profile at 120 from a positive tilted NE jet flow to a blocked neg tilt...

S

Hi

I admire your fortitude, but looking at the GEFS at D8-9 and there is zero interest, in fact solid agreement despite your opinion that it can all change after D7: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=216

The fact there are subtle changes in the short wave pattern yet the long wave pattern seems to be solid suggests that these changes will just alter surface conditions and speed of transition and will have minimal effect on a pattern change. Again at D12: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=288 good support for the ops amongst the GEFS (for FI), though not as mild:

Based on these charts I would have higher confidence than of late on the next 10-12 days. But the good thing with weather it can flip flop quickly though I see little interest on Twitter for any driver for change currently.

[nick sussex]

12 minutes ago, IDO said:

Hi

I admire your fortitude, but looking at the GEFS at D8-9 and there is zero interest, in fact solid agreement despite your opinion that it can all change after D7: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=216

The fact there are subtle changes in the short wave pattern yet the long wave pattern seems to be solid suggests that these changes will just alter surface conditions and speed of transition and will have minimal effect on a pattern change. Again at D12: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=288 good support for the ops amongst the GEFS (for FI), though not as mild:

Based on these charts I would have higher confidence than of late on the next 10-12 days. But the good thing with weather it can flip flop quickly though I see little interest on Twitter for any driver for change currently.

Yes but every early change like the butterfly effect can culminate in bigger changes later. Take for instance the  change in tilt and orientation of the shortwave over the central USA, this impacted the amplitude of the Atlantic low and clearance of shortwave energy to the north at a critical timeframe.

And of course weather is fluid, every action has a reaction if you know what I mean. The upstream change effectively was picked up only today so it could be that this might take some time to feed into the more medium term. I'm not saying that we should get our sledges and ear muffs out but for the timebeing should keep an open mind in case these changes within the T144hrs timeframe start to have a greater effect down the line.

To use a couple of analogies. If you change the start of the book you might get a different ending! or for poultry lovers, what comes first the chicken or the egg, we might get a happier chicken which might lay a better egg!

Edited November 26, 2016 by nick sussex

[Frosty.]

The Gem 12z isn't interested in anything wintry, quite the opposite in fact as it bathes the uk in mild air later in the run.

 

 

 

Edited November 26, 2016 by Frosty.

[booferking]

Great upgrades today so far from the 3 main models from the position we were in Yesterday hopefully the ECM continues the theme shortly. No point looking beyond 168hr until the earlier stages are settled.

Edited November 26, 2016 by booferking

[Summer Sun]

Next weekend could see another chilly snap before temperatures recover during the 1st full week of December - we then see a downward trend as we approach mid month

[Methuselah]

Haven't seen upgrades like these for yonks; not since at least 2012-13.

[chris55]

GFS caught my attention this evening, no silly cold FI charts, but certainly a very positive set up as we enter winter 2016/17.

 

[gottolovethisweather]

24 minutes ago, Summer Sun said:

Next weekend could see another chilly snap before temperatures recover during the 1st full week of December - we then see a downward trend as we approach mid month

 

 

 

Yes, the first proper cool to cold spell (below average for at least 3-4 days consecutively next week) upcoming for London and the SE area in general. Nothing new for parts due North of the Midlands and parts of Ireland as they've endured several cold days of late. Judging by that graph as others have stated don't put too much faith in any model outputs past the 1st/2nd December right now but look for interconnected scenarios across the 12zs and days past. A long haul to snow filled conditions but the cold is a-coming in. Over to the ECM and I'd suggest you shouldn't panic if it diverts back to an alternate scenario past D7, as it's simply toying with all the uncertainties at that timeframe and beyond. Main takeaways to hope for if a coldie, is a blocked Atlantic and an increasing depth of cold over the nearby continent. 

 

EDIT: Oops, the ECM operational is having none of the above, so far it seems. However, we should never take the forecasted 850s as gospel, whether looking for either milder or colder solutions as lingering FOG will result in huge differences at the surface.

Edited November 26, 2016 by gottolovethisweather

[A.J]

 

*very important*

GFS, ECMWF, UKMO, JMA & NAVGEM have now finally come together.......the announcement has just been made on facebook.....relationship status: "It's complicated"......yup, that sums up the models quite nicely! lol

[gottolovethisweather]

1 minute ago, ajpoolshark said:

 

*very important*

GFS, ECMWF, UKMO, JMA & NAVGEM have now finally come together.......the announcement has just been made on facebook.....relationship status: "It's complicated"......yup, that sums up the models quite nicely! lol

 

I prefer the relationship status of "Not Telling" which is presumably more accurate. 

[stratty]

Back to the models you two please! 

[northwestsnow]

Ecm not going to be as good as this morning imho, more energy south tip of Greeny at 96....

[Methuselah]

21 minutes ago, chris55 said:

GFS caught my attention this evening, no silly cold FI charts, but certainly a very positive set up as we enter winter 2016/17.

 

To me, that big wodge of HP looks primed to retrogress...If it does the flood gates would surely open...Yee Ha!

[A.J]

2 minutes ago, stratty said:

Back to the models you two please! 

BOOM!.....apologies ......erm, erm, erm, GFS looks nice, if you like quiet weather (he says, desperately trying to sound on-topic) 

[Captain Shortwave]

The problem with saying that there is good model agreement at day 8 onwards is quite simply this.

This was the output for day 6 yesterday

      

Now 24 hours later we have decent agreement for this...

      

Looking at this, the ECM seems to be ahead of the game as the chart 24 hours ago wasn't too far off, the only difference was a secondary low which ran north east and flattened the UK ridge (base of the Atlantic trough). The other two have now come around to the same broad longwave solution now.

Now the GEFs at around day 8 allow the Azores high to ridge north east and cut off the low heights to our south west and hence send the jet over the top, hence the mild mean solution. What if this situation does not occur as seen by the transformation over the past 24 hours? Whilst the GEFs show reasonable longer range consistency, I would treat this with caution given the chance that the upstream jet could again split against heights near the UK.

I will say that whilst the ECM day 6 is not as good as this mornings, that high will hold and not drift ESE.

Edited November 26, 2016 by Captain Shortwave

[Frosty.]

if you like high pressure there's lots to like about the Ecm 12z, it looks fine and benign.

Edited November 26, 2016 by Frosty.

[karlos1983]

Back from behind the sofa as the ECM keeps the trend of this morning and the subsequent 12z gfs and ukmo. Now we can hopefully start to improve on this and perhaps get some decent uppers towards the uk. Tall order but not impossible at all.

edit: I would say we have now bought our ticket. 

Edited November 26, 2016 by karlos1983