Model Output Discussions 18z 31/01/2016

[Methuselah]

3 minutes ago, mulzy said:

Indeed, the Met Office did not ramp the event though they do cover themselves by the term "rain or snow"....

It might seem like a daft question - but, in a situation as obviously marginal as this one, what else could they say?

[Frosty.]

1 hour ago, weirpig said:

 i just want one bloody snowflake.

There you go..

[booferking]

12 minutes ago, feb1991blizzard said:

The ensembles have completely imploded as well.

Was waiting for the report on ensembles didn't dare want to look at them myself your comment is suffice..

Edited February 12, 2016 by booferking

[weather eater]

1 minute ago, nick sussex said:

I have to disagree with the use of anomaly charts and the midweek trough disruption issue. Small scale detail as to whether you get suitable disruption to not mix out the cold won't be picked up by the NOAA anomaly charts. These just give a broadbrush view of anomalies against previous climatology.

You can't use an anomaly chart for specific detail. If you're looking at the overall pattern to get a rough idea that's fine but for next week its the NWP which supercedes the anomalies.

Yes a broad brush Nick but if the broad brush is not indicative of a proper cold spell then there will be no proper cold spell. The details may well feature a transient colder spell as we are now seeing but the fact is that for most of us are looking for something more than a 2 day northerly. However, my main point is the futility of expecting runs to be consistent post a couple of days, it's never going to happen. We could point to 2010 but even then the details kept changing in the run up, what made it stand out was the fact that the changes stayed in a cold theme.

[joggs]

I think best we can do for snow is the Ecm bring front through quicker,and GFS ukmo to follow and try let the Atlantic high push north behind the trough before the next one exiting the states.I think a nw airflow is our best bet for snow for the remainder of this extended autumn.Not good for the se though.

I don't fancy eeking cool days out of this set up with rain(snow on hills) with a decaying front.

Edited February 12, 2016 by joggs

[Redwood]

I hold my hands up.  It was me.  I made the mistake (will I ever learn) of broadcasting "its gonna snow".  Sorry

[Ali1977]

I'm really surprised after 2 very similar runs that the 12z completely changes its mind. Strange and hopefully not true!!

[Northern Sky]

From elation to despair in 6 hours! I suppose following the ups and downs of the models is all part of the fun but the reality is the vast majority of the time the eye candy cold charts don't happen. Of course there are exceptions such as 09/10 and Dec 10 and it may be that those events have spoiled us into thinking those fantastic charts are going to come true again. Well one day they will but not next week.

Of course there could be upgrades and it will certainly be a cold few days, which in the context of this Winter will make a pleasant change.

[nick sussex]

Typical now the ECM is better than the GFS at T120hrs! From hero to zero in the space of 6hrs for the GFS.

[mushymanrob]

46 minutes ago, nick sussex said:

I have to disagree with the use of anomaly charts and the midweek trough disruption issue. Small scale detail as to whether you get suitable disruption to not mix out the cold won't be picked up by the NOAA anomaly charts. These just give a broadbrush view of anomalies against previous climatology.

You can't use an anomaly chart for specific detail. If you're looking at the overall pattern to get a rough idea that's fine but for next week its the NWP operationals which supercedes the anomalies.

 

absolutely nick, but as i replied earlier, the stalling/slow moving midweek frontal system bringing the snow was relying on a more amplified ridge, some runs even evolved this ridge into something more potent for cold. the noaa always suggested a trough over the uk for next midweek which would allow for a short lived ridge, but not one the strength the gfs was suggesting - the one needed to stall the frontal system and deliver the snow.

[Purga]

What does Nick Sussex think of this?

looks to be flattening out unfortunately.

[Ben Lewis]

The disappointment by models always showing the cold in lala land only to be downgraded nearer the time, has nothing to do with poor output stats.

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

But as always it will fall on deaf ears, when the next cold is projected in FI, be it this winter or next the usual 'big ups' will apply, followed by 'prozac' moments as we are seeing tonight.

Rinse & repeat! As you were... A vicious circle that quite frankly we are all addicted to. 

[nick sussex]

3 minutes ago, mushymanrob said:

absolutely nick, but as i replied earlier, the stalling/slow moving midweek frontal system bringing the snow was relying on a more amplified ridge, some runs even evolved this ridge into something more potent for cold. the noaa always suggested a trough over the uk for next midweek which would allow for a short lived ridge, but not one the strength the gfs was suggesting - the one needed to stall the frontal system and deliver the snow.

The ECM doesn't mix the cold out, its not a stalling front but still a chance of snow. The stall and block to the east win of course would need ridging further north with less energy spilling over the top. You don't need the front to stall to bring snow just for the cold to not mix out ahead of it. At this point it could still go either way in terms of mid-week snow.

[joggs]

11 minutes ago, Purga said:

What does Nick Sussex think of this?

looks to be flattening out unfortunately.

Maybe the low over Greenland can zip se towards us and the Atlantic high can retrogress north,nw but before another low exits the states.Best outcome for coldies on that.

Edited February 12, 2016 by joggs

[mackerel sky]

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.

[Tim Brawn]

6 minutes 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.

exactly ,  it would appear a  T168 chart rarely verifies and a T240 from whatever source never verifies , if they are always wrong , then you would think that over time they would improve .   they clearly are a waste of time and maybe why the BBC stopped doing forecasts more than T120

 

[damianslaw]

It is a messy situation, and in these set ups as I said a few days ago, reliable timeframe is short, about 72 hrs max.. so is no surprise to see model runs change their tune.. GFS is most prone to change simply because it puts out 4 runs a day, compared to the 2 that most others do..

At this range, we should all remain unsure what might happen next week, yes the ensembles and broad picture does appear to be the atlantic trough winning out, but at the surface no-one at this timeframe can be certain how things may pan out, precipitation wise.

Snowfall in this country is notoriously difficult to predict, and it often comes down to nowcasting. Similar to thunderstorms, which develop at a micro level.

Always keep an open mind, and expect sudden twists and turns and surprises is the best approach.

Back to the models, I wouldn't at all be surprised to see the GFS 18z do a flip more towards to 6z output, not saying it will be verify, just saying don't be surprised if it does. ECM can flip flop about as well, as can all models, and they often do when in less than traditional set ups such as we have now.

This model watching can be exhausting and trying work!

[Frosty.]

12 minutes 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.

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

[Bob G]

8 minutes ago, damianslaw said:

Back to the models, I wouldn't at all be surprised to see the GFS 18z do a flip more towards to 6z output, not saying it will be verify, just saying don't be surprised if it does. ECM can flip flop about as well, as can all models, and they often do when in less than traditional set ups such as we have now.

This model watching can be exhausting and trying work!

I was just thinking along the same lines - if things have changed for the worse over the last 18 hours or so, what is to say that they won't change back over the next 18 hours or so? These are only computer simulations in the real world the weather will do what it wants to anyway.

Come on, collective chins up 

Edited February 12, 2016 by Bob G

[nick sussex]

Its a pretty brutal world if you're an NWP model. Lauded one day then cast aside with disdain the next.

The GFS now finds its in the position of having its invitation withdrawn, the life and soul of the party now trudging wearily home by itself.

This often happens with one output going on its own way for a few days, when it comes back to earth it does so with an almighty crash!

[Nouska]

18 minutes 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.

Is that really the case or is it that more frequent extremes and contrasts in atmospheric state is more difficult for the model algorithms to assimilate.

[J10]

Latest Snow/Ski Blog for the Alps, while we may (or may not) get snow this weekend and next week, much more certainty after fair amounts of snow for the Alps in the same time frame.

[snowray]

12z Euro4 just about sums things up, chart for 12z Sunday. Nice Easterly there but all rain, not even sleet, apart from Northern mountains.....

[Bradowl]

6 minutes ago, snowray said:

12z Euro4 just about sums things up, chart for 12z Sunday. Nice Easterly there but all rain, not even sleet, apart from Northern mountains.....

That's because mainland Europe as been so mild for past week or so. 

Probably need this set up for a good few days before we dragged some really cold air across from east of Europe. 

[Man With Beard]

4 minutes ago, snowray said:

12z Euro4 just about sums things up, chart for 12z Sunday. Nice Easterly there but all rain, not even sleet, apart from Northern mountains.....

It just needed to hang around another 6 hours (which I appreciate is not looking likely now). If you look at dew-points/uppers/thicknesses, you'll see that they are becoming more favourable through the day - and indeed already will be north of Birmingham, so any showers blown in off the north sea will probably be snow inland - I'm sure there will be some too!

I still think the SE could see something on Sunday evening - the ECM precipitation chart shows light stuff still hanging around at 6pm:

scattered snow showers over other eastern parts too

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.