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

[mountain shadow]

We have to accept the models got it wrong initially and we won't get a slider and will be back into a Westerly pattern by Wednesday.

No use crying about it. Enjoy whatever you get over the next few days then its back to FI watching.

[SMU]

There is 'SOME' good news tonight.

 

The slider low in its adjustments over the day ( im referring to the second one- the main one ) has picked up slightly a more northerly starting locale when it enters the UK

 

here illustrated is yesterdays 12z entry point

 

http://modeles.meteociel.fr/modeles/gfs/archives/gfs-2015011512-0-108.png?12

 

V tonights 18z @ 108

 

http://modeles.meteociel.fr/modeles/gfs/runs/2015011618/gfs-0-108.png?18

( notice no time change across 24 hours )

 

You will see instead of the Ireland entry point has been replaced by a system coming down via Iceland.

 

The net fallout from this is less of a milder SW TM feed ahead of the frontal zone & more of a potent under cut from the NW into the rear of the front. as a result it will become occluded & there will possibly be a triple point.

 

Looking at the18z surface temps even the SE doesn't get above freezing until T156 ( barring a 3-6 hour period ) when the front moves through & that's only to +1 degree

 

so as it stands its still balanced nice on a knife edge & with the front being at t120 plenty of wiggle room yet...

 

All the comments around the 18z being a downgrade are incorrect as they based mostly on assumptions - its actually an upgrade.

Also post 140 ignore the 18z flow the GFS wont amplify a second time to a nearer time value.

 

 

The 18z is closest we have has so far to a near all snow event.....

 

 

best regards

Steve

Edited January 16, 2015 by Steve Murr

[Daniel*]

We have to accept the models got it wrong initially and we won't get a slider and will be back into a Westerly pattern by Wednesday.

No use crying about it. Enjoy whatever you get over the next few days then its back to FI watching.

Not true if it can flip that much why can it no do the inverse? the volatility at such a short timeframe is exceptional thus nothing can be discounted at this stage. Throwing toys saga... yet again.

[Mucka]

We have to accept the models got it wrong initially and we won't get a slider and will be back into a Westerly pattern by Wednesday.

No use crying about it. Enjoy whatever you get over the next few days then its back to FI watching.

 

Nah too early to give up. It has been a bad day for coldies no doubt but let's see what tomorrow brings.

[blizzard81]

I have to say I am shocked by the vastness of the turnaround in the output today. Yesterday the low was going to slide right through the UK and introduce an Easterly (of various potency) but today that has all gone and it looks very much like we get no slider at all and we will be in a Westerly flow instead!

It's a staggering backflip and goes to show how nothing at mid range can ever be taken as read.

Of course, the positive is that all could change again and it also shows that any predictions (cold or mild) beyond five days simply cannot be relied upon.

I stated the trend after yesterday's 12z runs and unfortunately that trend has gained momentum today. Too much energy to our north west, the pv just will not give up the ghost. I think all the main models were guilty of showing an icelandic/norwegion pressure rise and all were wrong. Why is this? An epic fail for the models in this respect.

[bluearmy]

this maybe the time to stand back a little from todays nwp. NOAA cpc comment that upstream, they are very unhappy with continuity from yesterday and have low confidence in the current output. the overall pattern has lost some amplification which moves it too far east for us to stay in the action for very long. what if upstream is wrong today on the nwp and tomorrow sees the amplfication return in the models ? it wouldnt be the first time that we see a bit of tooing and froing prior to the onset of a cold period.

 

perhaps the booing and gnashing of teeth should wait another 12 hours? maybe 24. after all, most wise posters indicated tomorrow evening as being when we would get a decent handle on the track of the trough.

[weather eater]

No back flip has occurred just the same old problem when viewing model output in that the evolution doesn't just stop or carry on in a theme that suits us, that's why stella charts at 120hrs plus and often less are of as much use a marzipan very stiff thing often used in the bedroom. what remains to be seen is how they will evolve from here but given the starting place and the lobe of the PV sitting over Greenland like an angry wasp it will be not to our liking for a while I think.

Edited January 16, 2015 by weather eater

[TSNWK]

It has not been a sudden flip.. The models have wobbled and stumbled in one direction for the last 24 hours since yesterday evenings high point..

Very hard to reverse the trend for the middle of next week onwards, as we get nearer the signal becomes stronger and this 18z might be the first run post tipping point.

[mountain shadow]

Nah too early to give up. It has been a bad day for coldies no doubt but let's see what tomorrow brings.

As far as I can see, every model now goes with a deeper low and the models handle zonal much better than blocking.

I cannot see a big turnaround now.

[stewfox]

No but it is the trend throughout all the output throughout the day that makes it soul destroying for coldies, it has only gone one way unfortunately.

Someone flicked a switch somewhere.

Azores high and the jet seem to be a factor now ?

[damianslaw]

GFS playing around with various scenarios I think this evening - BBC and Met Office certainly not buying it, and I would give it very little credence.. Yes an occluded front will occur and pivot and slide SE.

 

Its not long ago many seemed to bemoan the GFS 18Z on daily basis, suddenly it has the pattern right, watch it do  a back flip tomorrow, it is notorious for flip flopping from day to day, more so than any other run..

Edited January 16, 2015 by damianslaw

[Geordiesnow]

Not true if it can flip that much why can it no do the inverse? the volatility at such a short timeframe is exceptional thus nothing can be discounted at this stage. Throwing toys saga... yet again.

 

Reason why its unlikely to flip again is because we are closer to the reliable time frame and the trend is for more energy to push out of the states/canada which has an affect down the line for us, these things can and do happen regardless of the weather type we face hence we can see charts which look bleak turn in favor for cold lovers. its all part of the volatile nature of the weather. 

 

Models were right with it turning colder but they look incorrect in predicting a slider low through the UK however there is still some snow potential when we do get a breakdown from the West, just got too see if this will turn out in the favor of snow lovers or not. 

[bluearmy]

GFS playing around with various scenarios I think this evening - BBC and Met Office certainly not buying it, and I would give it very little credence.. Yes an occluded front will occur and pivot and slide SE.

 

not according to the latest FAX. the first occlusion clears east with sub 528 dam air behind as the raw ukmo showed. the parent low is beginning to head se as per the 12z model and in the west atlantic, the next system looks to be struggling to make n latitudinal progress.

[i luv snow]

It is only just one run, so we don't actually know if this particular one of one particular model is right or wrong. Even if it is right, there is still snow to be had, but I highly doubt it will verify like this. Needless to say, let's see how the next few runs turn out - you can't write anything off just yet, and regardless there are still a good few days of very cold air. Nighttime temps will be between -10 and -15oC for some over the weekend, with snow for various areas, and that won't budge easily. At least not 18z GFS easily.

Edited January 16, 2015 by i luv snow

[Mucka]

As far as I can see, every model now goes with a deeper low and the models handle zonal much better than blocking.

I cannot see a big turnaround now.

 

That is the worrying part, that it has been cross model, cross ensemble strengthening trend so it is not as if one model has bad data or they re flip flopping between them.

Even so we saw fairly dramatic switch to the cold signal and now we have seen a fairly dramatic switch back the other way so we can't be sure the models have things pinned now after so many struggles.

I wanted to punch my monitor in TBH, we snow freaks all suffer the same, but there is definitely still hope even if it is painful to keep having those hopes dashed.

 

Go back to ECM 12z and this is the 850 ensemble mean for 192

 

 

In between we would have about 4 days of proper cold and some chilly days with wintry ppn mix across the country.

If that is what transpired it really wouldn't be so bad.

[weather eater]

Anyone any Ideas what changed this reversal in fortunes?? What did the models get wrong or predict wrong??

Nothing they just did the maths based on the data they had at the time, I can't stress this enough you cannot rely on computer synoptic modelling post 120hrs sometimes less and to do so in regards cold and snow will result in tears almost every time.

[Met4Cast]

"It's only one run"

 

The above statement can be bought when it IS just one run. But we've been trending this way for several runs on several different models. Yes, it might be an upgrade in the short term as far as snow potential, but it's a downgrade in the longer term and I think it's the longer term most of us are worried about. Having snow on the ground for a day before the thaw sets in isn't really what most of us are looking for.

 

Clear trend for the high to collapse and Westerlies to return by next weekend now, as I stated yesterday but was gunned down with the "it's only one run" comment. Still time to change? Sure, but not a whole lot of evidence for heights remaining in the right places as per Ians F's comments earlier this evening.

 

A few days ago we were looking at a possible snowy Easterly after the sliders. Now we're looking at a watered down version, a bit of snow for the lucky spots then back to the mobility regime. 

[Paul]

I think I moved/removed my first post of the day at about 7am this morning, it's now nearly 11pm and we're still going - please can you let me and the others in the team go to bed and just pre-moderate your own posts from here on in - that means for the small minority who still don't seem to want to do it, please post in the banter thread if you want to have a good old moan or whatever else, and keep his thread to discussion of the model output. 

 

Thank you!!

[Jason M]

It has not been a sudden flip.. The models have wobbled and stumbled in one direction for the last 24 hours since yesterday evenings high point..

Very hard to reverse the trend for the middle of next week onwards, as we get nearer the signal becomes stronger and this 18z might be the first run post tipping point.

Yep, the trend has been there ever since the old GFS went out in a blaze of glory. We can't seem to sustain any northern blocking at all this winter (just as per last winter really).

I have known the models do this before and then bring back cold charts with a vengeance the next day, so as others have said things can change. What concerns me though is the trend towards a rampant PV just where we don't want it again. Its not good to put too much stall in FI charts (or one run tbh) but trends should not be ignored. Hopefully tomorrow brings a new trend!!

GEFS will be interesting again this evening to see if they are starting to cluster around an early breakdown.

[Smiler1709]

I think the models are having a mare with his to deal with this cold situation, think we're gonna have to wait another 48 hours before the details get ironed out. Shame about the downgrades but still plenty to play for. New day tomorrow and a new set of runs.

[mountain shadow]

Nothing they just did the maths based on the data they had at the time, I can't stress this enough you cannot rely on computer synoptic modelling post 120hrs sometimes less and to do so in regards cold and snow will result in tears almost every time.

I would say the can be reliable up to 192 hours in a strong Westerly zonal pattern, throw in a hint of blocking and that drops to 72/96 hours.

[khodds]

I think I moved/removed my first post of the day at about 7am this morning, it's now nearly 11pm and we're still going - please can you let me and the others in the team go to bed and just pre-moderate your own posts from here on in - that means for the small minority who still don't seem to want to do it, please post in the banter thread if you want to have a good old moan or whatever else, and keep his thread to discussion of the model output. 

 

Thank you!!

Thank you for all your hard work, it really is appreciated is there a way that people who repeatedly do it can be penalised or banned? To give you an easier job

[Gibby]

A distinct correction West on tonight's 120hr fax when compared with the raw data of the earlier 12z.

http://www.meteociel.fr/modeles/ukmo2.php?carte=2000&ech=0

[damianslaw]

I think I moved/removed my first post of the day at about 7am this morning, it's now nearly 11pm and we're still going - please can you let me go to bed and just pre-moderate your own posts from here on in - that means for the small minority who still don't seem to want to do it, please post in the banter thread if you want to have a good old moan or whatever else, and keep his thread to discussion of the model output. 

 

Thank you!!

 

 

Its a shame it has to get like this in here - there is a model moaning thread etc which people don't seem to be using - incidentally that thread is something I very rarely dip into - it is utterly depressing. To keep my sanity I will be dipping into the regionals mostly with a glance through the MOD thread but if today is anything to go by, I may just simply go into the regionals and spend time actually enjoying the cold spell rather than reading posts about when it is going to end - I do sometimes wonder if people actually spend any time enjoying the here and now..

Edited January 16, 2015 by damianslaw

[Mucka]

JMA 18z

The first model to correct itself back West. Let's hope it is anew trend!