Model Output Discussions 18z 31/01/2016

[karyo]

8 minutes ago, Man With Beard said:

 

We just need the front to stall/slow significantly so it can be affected by dry/cold SElys. I think the 850s will be sufficient if a continental sourced wind gets to work on the front. The 12Zs generally had a bit too much on the front to stall it or slow it, but way way too early to say it won't stall. T72 will be the earliest we can really call that one.

More chance to see some snow showers with the northwesterly that follows in the ECM. It is shown to be cold enough (at the moment). It can easily downgrade as well of course.

[weather eater]

56 minutes ago, Karl. said:

It's not the models getting worse it's just a few extremely poor British winters, you can't blame the models for that..the models generally speaking are much better than they were when I joined NW in 2005...in my opinion

Couldn't agree more Karl. In fact the GFS has done really well here, it picked out the general pattern and stuck with it. Only on a couple of occasions has it hinted at a longer cold spell and it's our hopes and expectations that lead us up the garden path at times. We all have to face it, we are a tiny island and 50 miles N,S,E or west makes a big difference. And I really do feel that we need to keep in mind what is going on under the hood of these models. Some serious mathematics with numbers that are already old even before they are run. Far from being poor they do a fantastic job every single day of the year. But the further you get from zero hour the more they are going to be wrong. What is needed by those of us who view them every day is a change of onus. From will this run verify to how much and from what point is this run going wrong. For the UK I would suggest that's day three at best most of the time. Of course the ensembles are supposed to be a guide for this but all too often they are either not up to the task or they are cherry picked for cold.

 

Edited February 12, 2016 by weather eater

[Frosty.]

The JMA 12z looks similar to yesterday and much less progressive than the other models, quite a cold pool developing with sharp frosts, in the longer term, the south stays fine with night frosts whereas it becomes more Atlantic driven further north. I still think things are finely balanced regarding the second half of next week, a few ordinary op runs doesn't mean it's game over for more wintry conditions.

[johnholmes]

1 hour ago, mackerel sky said:

I joined this forum many years ago, I think in 2003 as member 500 or so - I have never seen such a poor verification of models. Getting worse not better.

also to TB below the above post

It is of course a difference we all see between what we feel was the case 10 years or more ago and actual verification statistics from the main 3, be that actual forecast verification from UK Met or upper air verification from the other main two (ECMWF and GFS), all of which, unless you think they are concocted, which is frankly ludicrous, show slight, in some cases very slight, improvement in that time.

[Nick F]

18 minutes ago, Man With Beard said:

Regards Wednesday, a bit too early to write off the snow chances (though I can understand the desire to do so with so many snow opportunities vanishing in the past week). Looking at the ECM at T126, lots of precipitation around.

We just need the front to stall/slow significantly so it can be affected by dry/cold SElys. I think the 850s will be sufficient if a continental sourced wind gets to work on the front. The 12Zs generally had a bit too much on the front to stall it or slow it, but way way too early to say it won't stall. T72 will be the earliest we can really call that one.

12z EC on weatherbell showing a period of snow for Scotland, N England, Wales, Midlands, Lincs and E Anglia as that frontal system moves through, though not further south. So perhaps, just perhaps, some transitory snow in places even to lower levels next week for those not near the coasts before it's back to westerlies and snow confined to northern hills.

Must admit the 00z GEFS stamps this morning were convincingly supporting the operational, but it appears now the GFS op could be playing catch up with ECM and the anomaly charts from EPS and NOAA which have maintained that troughing will push down from the NW and east into Scandinavia. All the more reason to follow these anomaly charts for guidance, as John Holmes helpfully updates us on, rather than the ops, when there are differences appearing between the models.

 

[Rob Deacon]

i've been reading the model forums since before this forum was born, and 1 thing has not changed in them 15 plus years, you get lead up the garden path thinking this time it's some how going to get it right and big snow will come, 99.9 times out of 100 it doesn't, but i never learn.

but im cool with that, all part the fun in this thread really.

I now drive to the Arctic circle with a mate every year for a snow fix, bit extreme maybe but it works

[Man With Beard]

A very great number of colder options on the ECM T120 postage stamps:

http://old.ecmwf.int/samples/d/inspect/teasers/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!120!pop!od!enfo!enplot!2016011600!!/

[phil nw.]

There is some detail to be agreed wrt the midweek trough as it comes in off the Atlantic and where if any snowfall will occur.It does look though that this will bring in a more westerly pattern behind it though with less cold air.

Day 10 height anomalies from GFS and ECM ens 

the one area of low pressure again stuck like a limpet to our north.A trend building though for an increasing influence from the high pressure in the south which should at least mean a drier period away from the far north.

We can see from the Warks. gef graphs rainfall amounts are forecasted to be very low in fact for the next 2 weeks and temperatures trending towards normal after the coming week as the Atlantic westerlies take over.

 

 

[Cleeve Hill]

51 minutes ago, kingdeacon said:

i've been reading the model forums since before this forum was born, and 1 thing has not changed in them 15 plus years, you get lead up the garden path thinking this time it's some how going to get it right and big snow will come, 99.9 times out of 100 it doesn't, but i never learn.

but im cool with that, all part the fun in this thread really.

I now drive to the Arctic circle with a mate every year for a snow fix, bit extreme maybe but it works

Talking of snow fixes next week we are off to Tromso next Tuesday for an artic jaunt. Third time we have gone in search of Northern Lights (2failures so far). Been looking at the charts and those GFS charts were just the job for North Norway but now it looks like changing with the High never really in place. 

At least we'll see some snow but it's clear skies we want. 

[Eskimo]

I said I wouldn't post until probably next winter and just observe until then, however the last few days really have been gripping.

Shame though that the 18z is ever more progressive it seems.

 

EDIT: Mixing out the milder uppers far better though!

Edited February 12, 2016 by PerfectStorm

[Faronstream]

12 minutes ago, PerfectStorm said:

I said I wouldn't post until probably next winter and just observe until then, however the last few days really have been gripping.

Shame though that the 18z is ever more progressive it seems.

 

EDIT: Mixing out the milder uppers far better though!

So the westerlies will take over in long range? I really thought the GFS would become true with -25 Celsius in London again -,-

[Rob Deacon]

41 minutes ago, Cleeve Hill said:

Talking of snow fixes next week we are off to Tromso next Tuesday for an artic jaunt. Third time we have gone in search of Northern Lights (2failures so far). Been looking at the charts and those GFS charts were just the job for North Norway but now it looks like changing with the High never really in place. 

At least we'll see some snow but it's clear skies we want. 

I find this the good thing with going to Norway in winter, you either see the northern lights or snow

[Ice Day]

At least there's been a bit of a rebound (maybe a dead cat bounce!). but this is a better run up to 132.  Uppers are colder and better heights into Scandi.  We've fallen back a long way today, who's got the stamina for another few days trawling for upgrades????

 

[Tim Bland]

The roller coaster of model runs continues! GFS 18z is similar to the 06z output and most places wake up Thursday to a covering of snow 

[I remember Atlantic 252]

North to get a bloody 'ammering, another trough disruption Fri am, not good though for my location

[feb1991blizzard]

3 minutes ago, Tim Bland said:

The roller coaster of model runs continues! GFS 18z is similar to the 06z output and most places wake up Thursday to a covering of snow 

And another go on Friday as well.

[feb1991blizzard]

Some advice though re - that second slider on Friday, In all seriousness I would treat it as an outlier solution (synoptic wise not temperature) at least until it has more support,

[booferking]

4 minutes ago, feb1991blizzard said:

And another go on Friday as well.

Yep having another go.

Edited February 12, 2016 by booferking

[Fozfoster]

11 minutes ago, Tim Bland said:

The roller coaster of model runs continues! GFS 18z is similar to the 06z output and most places wake up Thursday to a covering of snow 

Thanks for the picture Tim . This morning the sweet spot was southeast now northeast, no one knows yet. So enjoy the ride, it's been a long old winter........... Where's my towel!!;-)

Edited February 12, 2016 by Fozfoster
Name

[booferking]

9 minutes ago, Tim Bland said:

The roller coaster of model runs continues! GFS 18z is similar to the 06z output and most places wake up Thursday to a covering of snow 

Yep good for most of England Scotland Wales not so much Ireland.

[feb1991blizzard]

1 minute ago, booferking said:

Yep having another go.

Unfortunately though no other model agrees.

[gottolovethisweather]

3 hours ago, Karl. said:

It's not the models getting worse it's just a few extremely poor British winters, you can't blame the models for that..the models generally speaking are much better than they were when I joined NW in 2005...in my opinion

Indeed Frosty/Karl and another important aspect to consider are the timescales involved.

A note to all...................................................

When and if people get hung up about inter-run differences at t+144 which show those ultimately salivating uppers of +20 850s in Summer or -10 in Winter one minute and hey ho , they're gone the next run, why are they surprised at this? People are of course always going to be disappointed when they disappear from one run to the next, yet of course this random climate/weather variation of type is to be expected when speaking of t+12000 minute timescales (equates to only five days ahead if my sums are correct). 

What folk need to do is save their own charts of interest to the cloud or on their tablet/pc/laptop over a period of days and see just how much variation there truly is at such a timescale, yet alone well within the reliable say <t+48 for instance. Our old hand John Holmes among others regularly tells us to try this approach and to compare like with like (eg. 12z with 12z) operational runs and only then can you get a reasonable idea as to why things do upgrade or downgrade against one's favoured weather type on a regular basis. 

 

Enough of that, this is borderline model output discussion at best, I suspect very much like those borderline rain/sleet/snow events upcoming. 

 

Edited February 12, 2016 by gottolovethisweather

[Pixel]

1 hour ago, kingdeacon said:

i've been reading the model forums since before this forum was born, and 1 thing has not changed in them 15 plus years, you get lead up the garden path thinking this time it's some how going to get it right and big snow will come, 99.9 times out of 100 it doesn't, but i never learn.

but im cool with that, all part the fun in this thread really.

I now drive to the Arctic circle with a mate every year for a snow fix, bit extreme maybe but it works

Keep on trucking my friend..

You'll have more laughs going to where you know the snow is than searching for it on here - but yes it is exhausting reading hopeful posts in this thread over every winter - been there, wish I had a printed T-Shirt. Can't think of a caption... maybe there's a new thread for that.

sorry mods can't help my empathy... Maybe there's a brief southerly wisp to the jet stream to encourage moist warmth to come up against the cold in this classic feb set up?  but more importantly which side (above or below) of the M4 is it going to be? 

[booferking]

1 minute ago, feb1991blizzard said:

Unfortunately though no other model agrees.

The PV really is something this year so well organized gets hit every direction and always seems to regroup again were we don,t want.

[kumquat]

Quote

Its due to my fellow weather enthusiasts believing and building hopes on charts a week away.

Yes, but sometimes they do verify and that is The Chase.