Model Output Discussion - 16th Jan 12z onwards - Smile While You Post!

[Bartlett High]

Shanon is back, but I would add ; Would we be analysing the movement of a low pressure in so much detail if it was going to just bring rain?  Most of us probably don't even notice just how often the models are varying at such a short time frames as we are just glazing over the output looking for cold synoptics. 

 

FWIW my gut tells me that this coming week is just a taster, The atalntic may get in for a few days next week but it is only a matter of time before a major reload of NH blocking!

Edited January 16, 2015 by bartlett high

[JoeShmoe]

Im looking at UKMO thinking it would be actually be good for the North and Scotland - as perhaps reflected in those updated snow maps

[Bartlett High]

 

Shanon is back, but I would add ; Would we be analysing the movement of a low pressure in so much detail if it was going to just bring rain?  Most of us probably don't even notice just how often the models are varying at such a short time frames as we are just glazing over the output looking for cold synoptics. 

 

FWIW my gut tells me that this coming week is just a taster, The atalntic may get in for a few days next week but it is only a matter of time before a major reload of NH blocking!

 

So say  JMA !!

[Barking_Mad]

Perhaps a fantasy island thread would eliminate a lot of these 50year predicted charts. If we kept this thread exclusively for model discussion concerning the next 5 days it would help enable a clearer picture for noobs like me and all longer term predictions go in the FI thread

This. Please!

[blizzard81]

Shame we don't have the 850's for the ukmo but imo it looks as though the cold gets mixed out due to the low going too far east so probably a slushy mess at best!

[Long haul to mild]

And the Gem has gone for the easterly, maybe it's right maybe it's wrong doesn't matter what is important that its wise not to look too far ahead, not to get carried away and not get despondent about synoptic patterns that may never happen.gem-0-150.jpg

Yes, we want to see that verify if possible but with such a raft of solutions on the table it's hard to know what will verify. Patience is key here, a very interesting spell of weather.

Good to see you back on here WE, and good to have more East Anglian representation on the model thread; there's not all that many of us around nowadays!

[The Eagle]

The UKMO is not bad at all. A different evolution, yes, but it remains very cold in polar maritime regime and at 144 there are real prospects from the east if you take the sequence to it's logical conclusion at 192 hrs.

 

[shaky]

If the ecm doesn't back the ukmo tonight then i personally feel its gone of on one!! Also i dont think ive seen one t144 hour chart from the ukmo come of this season!!

[mulzy]

If the ecm doesn't back the ukmo tonight then i personally feel its gone of on one!! Also i dont think ive seen one t144 hour chart from the ukmo come of this season!!

 

Hmm, at 144 hrs, UKMO GM verification stats are pretty good.

 

There is also some support for the UKMO solution within the GEFS...

 

Edited January 16, 2015 by mulzy

[SE Blizzards]

Don't bother looking at the GEFS for any answers at Days 5 - 6, it's pure pandemonium.

 

Will the upcoming ECM give us any clear cut answers? I wouldn't bet on it!

 

Maybe Fergie can shed some light later on what Exeter's thought's are going forward. What a mess!

Edited January 16, 2015 by SE Blizzards

[knocker]

Well the GFS is going for a return of the set up prior to this after T156 with LP to to NW/N and the Azores high being naughty again. Jet running SW/NE and depressions forming off the eastern seaboard and dancing around the HP. Just thought I'd mention this, en passant, to give you all a break from the in depth analysis of next week.

Chart courtesy weatherbell

 

[Mucka]

Except for the embedded cold air.

To be honest I think we are hitting the lowest point of the output today and things will begin to improve again in future runs.

I could be wrong of course but I'm still hopeful the first low will slide and give snow for many and we will get get a second slider perhaps further East so not as cold but another Scandi ridge forming and undercut from there = Easterly. Obviously the way forward and the models will get there eventually. 

 

I'm with Steve TBH, there is almost no point in trying to analyse any op run or even the ensembles to determine what will happen but he like the rest of us will be watching the ECM and if it is kind posting excitedly about it. 

 

I'm just self quoting to save retyping same explanation.

One or two GFS ensembles showing such interest in among the Westerly dominated carnage and P15 is best example.

 

1st slider.

 

 

2nd slider.

 

 

Scandi ridge.

 

 

All that is missing is the final phase of undercut in FI.

So keep your feet on the ground but your head in the clouds then you will be quipped to enjoy all the lows and highs of the MO.

[The Enforcer]

Hmm, at 144 hrs, UKMO GM verification stats are pretty good.

I think that graph shows how much models struggle to accurately pinpoint the situation during spells of colder weather - see the dip in verification between Xmas and New Year coinciding with the other colder period of the winter.

Edited January 16, 2015 by The Enforcer

[MR EXTREMES]

If the ecm doesn't back the ukmo tonight then i personally feel its gone of on one!! Also i dont think ive seen one t144 hour chart from the ukmo come of this season!!

Second in the stats charts ukmo might be 3rd but even so I rate this model highly because it only goes out to 144hrs less margin for error could be wrong but it's not the worst I've seen plenty of scope for better progression towards cold even if it takes longer to get there.

Ukmo shows some wintry weather.

[nick sussex]

Tonights outputs sponsored by the De Vinci Code!

 

Any ideas as to which model would have a more accurate profile of the southern Greenland region? effectively this is the main point of contention.

 

If you look upstream theres little major difference, the UKMO is a bit weaker with the ne USA low and timing can be quite critical as the UKMO phases the energy with the low over Greenland just as this would start edging se, even 6 hours difference with phase time will effect the angle of low pressure into the UK.

 

The UKMO low is deeper which also is a problem, effectively theres a narrow tipping point between the GFS and UKMO. I think we best leave this to the ECM because at T96hrs its rarely wrong .

 

If the UKMO holds back the phasing then it could turn out much more interesting going forward, we await the ECM verdict!

[MR EXTREMES]

Well the GFS is going for a return of the set up prior to this after T156 with LP to to NW/N and the Azores high being naughty again. Jet running SW/NE and depressions forming off the eastern seaboard and dancing around the HP. Just thought I'd mention this, en passant, to give you all a break from the in depth analysis of next week.

Chart courtesy weatherbell

And it's most likely a different picture tomorrow the gfs is the best of the bunch and most certainly shows cold.

Even the chart you posted still shows cold and a possible return to polar nw flow maybe a westerly flow modified by polar air so certainly nothing above average for the foreseeable

[Chris K]

Don't bother looking at the GEFS for any answers at Days 5 - 6, it's pure pandemonium.

Will the upcoming ECM give us any clear cut answers? I wouldn't bet on it!

Maybe Fergie can shed some light later on what Exeter's thought's are going forward. What a mess!

Not sure if you have read his post from earlier but it pretty much sums their thoughts for now.

https://forum.netweather.tv/topic/82281-model-output-discussion-14th-jan-12z-onwards/?p=3122635

I realise we are lucky to have him posting here, but he does have his full time job and life to get on with!

Edited January 16, 2015 by Chris K

[SE Blizzards]

Not sure if you have read his post from earlier but it pretty much sums their thoughts for now.

https://forum.netweather.tv/topic/82281-model-output-discussion-14th-jan-12z-onwards/?p=3122635

I realise we are lucky to have him posting here, but he does have his full time job and life to get on with!

 

Ah, Thanks for that CK 

 

And yes, i fully agree, we are very lucky we have him.

Who'd be a forecaster at times like this hey!?

[gottolovethisweather]

Don't bother looking at the GEFS for any answers at Days 5 - 6, it's pure pandemonium.

 

Will the upcoming ECM give us any clear cut answers? I wouldn't bet on it!

 

Maybe Fergie can shed some light later on what Exeter thought's are going forward. What a mess!

 

Intriguing to note the different evolutions afforded to us by D5 with regard to the Atlantic High, I'd prefer a better elongated shape to the HP cell as mentioned yesterday, if it resembles an Omega block, we could prolong the cold to very cold spell beyond D7.

 

Here's the post and I'll check to see what this afternoon's run did by way of comparison.

 

https://forum.netweather.tv/topic/82281-model-output-discussion-14th-jan-12z-onwards/?p=3121292

 

 

GFS 12z chart at t+120.

 

 

Equivalent UKMO 12z chart at t+120

 

 

Better shape to the Atlantic HP cell on the GFS so perhaps that is what need to see develop longer-term. The more WAA pushing towards Greenland/Iceland and then surface features have to push over the top of the High and chances of an NE/E flow thereby increase into deep FI.

 

Reasonably likely to be some widespread snow about by then anyhow as shown below, some could be transient stuff in fairness but if heavy enough and Dewpoints are low enough it will produce the goods.

 

Edited January 16, 2015 by gottolovethisweather

[shaky]

Ecm please give us a ripper of a slidder!!! Coming out now!!

[SMU]

So here would be my take on the model suite this far tonight....

 

The models for the past 4-5 days have picked up on this reasonably shallow atlantic low pressure arriving from the North West around the 20th/21st of Jan-

 

Ahead of it there are modest heights over Scandi allowing for a bend in the jet SE wards- hence the system follows this track.

 

Things seemed generally 'well set' last night with confidence around a track that at the northern limit ( GFS ) was across the Midlands- with the Euros somewhat surpressed towards wales & the SW.- Even Cornwall was in the firing line....

 

Overnight ( also evident partially yesterday) the azores high has been modelled slightly incorrectly being that as the slider low approaches the UK the AH is actually supporting more of a burst of energy from the jet moving East.

 

This increased Easterly jet component has then spun the models into the current turmoil we have now.- If we look at ALL models the general them is ALL the same, a low pressure moving east recurving SE, however that SE curvature can be gentle ( ie faster jet ) - so models like the UKMO 12z catapault the system through the UK towards the low countries, where as the updated 12z GFS sees less of an energy burst allowing for a more acute jet & the slider moving south across the UK-

 

The actual net change is probably 500 miles of easterly movement ( as highlighted by the UKMO ) however for the UK thats going from being on one side of the polar front recieving snow to sitting on the warmer side getting a sleety mix.

( it is of course noted that Scotland could fair well out the UKMO track ) but this post is not about 'IMBY'

 

In this scenario no matter how many computers you lined up , how many pro or amatuer forecasters we have on here the situation for the slider is simply unforecastable with any degree of certainty.

 

So we have a choice of perhaps 3 avenues to go down in terms of ways of persuing possible 'best fit accuracy'.

 

* Super ensemble mean- a blend of the ECM / GFS ensembles for us - a blend of ECM / MOGREPS & Decider packages for the MET -  So the most important info that Ian F can supply tonight is where the UKMO 12z raw sits V that Mean.

 

* another way of forecasting this is via Analogues of what previous patterns have delivered for the UK, this is a very tricky route as we tend to have selective memory & only recall the ones that slid across the UK bringing snow as opposed to probably the countless ones that slid into Holland.- From my mind though most model solutions are usually to far EAST.

 

* or there is the wait & see method-  Chosen by many & certainly a far less volatile method.

 

I think from my perspective I am going to stick with my forecast cone from last night.....- ( if anyone wants to paste it up )

 

As for as the UKMO / GME blend is concerned today it feels so far east of the envelope it may be an outlier - although if it did varify I know why its happened.

 

In a nutshell the models are reacting to the slight re-morphing shape of the azores high & the subsequent jet which is making life difficult to pin down the break point where the propensity of the blocking to the NE starts to deflect the jet SE & of course how much by.

 

If all forecasting was easy there would be no need for people that actually 'forecast using experience' as opposed to ones just reading & disecting the model output daily.

 

Please no emotional rollercoasters over the next 24 hours from posters, I think were all past that now, plus theres a moaning & whining thread for that or better still a regional thread for when it goes t*ts up in your area then you can console each other- if you were to base a forecast on pure let downs alone you may as well say its heading for Debilt & come in & join the SE thread now!

I jest.

 

Have a good evening & enjoy whatever comes your way...

S

 

I forecast the ECM to be the same as the GFS track FWIW as that was along my best fit line last night.....

Edited January 16, 2015 by Steve Murr

[MR EXTREMES]

I wasn't making a point about warm or cold, merely a possible return to a familiar pattern. You really mustn't obsess so much

Oh no I was not obsessed over your post or the models either just replying to and agreed a return to what we currently have been receiving pretty cold polar air perhaps westerly at times with a mix of polar and tm although the tm air is less likely.

But all have the weak Scandinavia iceland weak ridge which is something of a plus.

The ao index has a very even split so this also reflex the model uncertainty.

[shaky]

Good 72 hours chart from ecm maybe?? Does it look closer to ukmo or gfs?

[gottolovethisweather]

So here would be my take on the model suite this far tonight....

 

 

 

Please no emotional rollercoasters over the next 24 hours from posters, I think were all past that now, plus theres a moaning & whining thread for that or better still a regional thread for when it goes t*ts up in your area then you can console each other- if you were to base a forecast on pure let downs alone you may as well say its heading for Debilt & come in & join the SE thread now!

I jest.

 

Have a good evening & enjoy whatever comes your way...

S

 

I forecast the ECM to be the same as the GFS track FWIW as that was along my best fit line last night.....

 

Regarding my first highlighted section, are you hoping to apply for the job of a moderator, Steve.    Re: the final highlighted comment, as per my post above I damn sure agree, ECM please please follow the mid-range GFS profile at the same timeframe but do not develop its deep FI output. 

Edited January 16, 2015 by gottolovethisweather

[West is Best]

Steve, good post but I'm not sure you are giving due attention to matters upstream, which is unlike you actually. The flattening jet, cyclogenesis off the eastern seaboard, concomitant lack of amplification and bifurcation are leading to the jet resurgent at a target called 'UK.' To use a phrase I think I first coined on here a decade ago: that's driving a coach and horses through any blocks.

 

 

 

It's true there are more amplified charts than that but broadly speaking unless this changes I fear the GFS have got the lead on this. Let's make the most of what we have for 4 or 5 days.

Edited January 16, 2015 by West is Best