Model output discussion - mid-winter

[Captain Shortwave]

Well at times it is best to compare like for like to see where the models have changed over the past 24 hours. The UKMO looks a good one to look at here;

   

Most of the differences appear to be over Canada with a much flatter pattern compared to the runs yesterday with heights also lower in general with the Canadian lobe still present as opposed to the weaker trough shown yesterday. End of the line the result is a stronger jet exiting N.America and hence the trend to move average conditions with winds generally from the west as opposed to potentially getting a northerly next weekend.

We do have higher heights over the pole which would cast doubt on whether we are seeing the right direction going forward as these tend to complicate matters, the bottom line is that things could change dramatically again (for better or for worse). Overall though the output this morning is a sharp turn away from previous days with the low Thursday night being the turd dumped on the stale cake this morning.

[Duane S.]

Well we’ve all been here before, familiar territory. There is still time for the charts to flip but it doesn’t look likely.

Im not referring to the track of the mid week storm, that will always be a last minute thing. Unlike a longwave trough, ‘base runners’ like this are notoriously difficult to predict. They can remain more of a wave or ‘bomb’ , depending on the timing of its interaction with the jet stream. Subsequently forecasts of their strength and track can and will vary wildly beforehand.

My concern is thereafter. I look upstream and don’t see a lot of help to drops heights below us and get the amplification we need to develop this into a decent cold spell. I have to be honest, I had great hopes that we were gradually heading towards a big cold spell going towards the end of January and into early Feb, my confidence is wavering a tad this morning! 

Let’s just hope the models haven’t sniffed out the right signal(s) here.

[ANYWEATHER]

Morning. A somber outlook from the models this morning with regards cold ,the winter Rollarcoaster can have big ups but unfortunately big downs. It looks as there will be some winter snow for some ,but perhaps the real news maker this week will be weds/Thurs low . Potentially stormy with damaging winds but it does zip through very quickly ,but still far enough away for some big changes. At face value this morning may look disappointing for coldest but it's just one run ,things cn change very quickly as most of the regulars on here know ,anyway have a good Sunday an interesting week ahead

[Polar Maritime]

Lots of off topic mainly moaning posts have had to go. Please keep discussions to what the Model Outputs are 'showing' or posts will continue to disappear to keep the thread running smoothly and clean.

And just a reminder that there is also the short range Model thread for detail over the next few days. With the regionals also there for Imby snow potential..

Many thanks, Please continue ☺

 

Edited January 14, 2018 by Polar Maritime

[nick sussex]

What a shocker.

The problem stems from the upstream failure to develop a more coastal low.

Instead phasing takes places further east and the pattern is flatter, downstream you can see the impact . 

No decent Atlantic ridge .

The ECM is the best of a poor bunch and has the most amplified pattern. It still goes pear shaped later but at least given the timeframes could improve .

Unfortunately the trend is against us.  I would be surprised if the ECM lasted the day.

The GFS has got even flatter overnight and the UKMO jumps ship aswell.

The shortwave low track which deepens is symptomatic of the flatter upstream pattern with it’s more northerly track.

Overall a hugely disappointing start to the day.

 

 

[Daniel*]

Not too sure on the pessimism. We have a memorable week in store.

T+42 the coldest zonal flow I’ve seen in years, you couldn’t ask for any better with origin, widespread wintry showers. While temperatures for instance may be appear too high in the S under showers they will drop like a stone.

Then we have Wednesday / early Thursday to contend with potentially a damaging Storm. Rather solid agreement for it to deepen as it crosses the country, this could be really bad. I’ve had a bad feeling about this for a while.

On Saturday GFS shows Atlantic breaking through however there is cold in situ meaning possible snow event before turning back to rain furthermore the cold could still well go on, a very interesting period. 

[Radiating Dendrite]

46 minutes ago, doghouse said:

Complete misconception regarding lowland areas of Scotland ie the most densely populated central belt....but hey, weather warnings for severe weather which covers almost 36 hours and probably involves all manner of chaos is not worth the mention,even is this particular pattern was described as rare as hens gold teeth not more than three days ago..... which incidentally equates to roughly 34 years as this was the last time such a westerly pattern delivered for parts of the UK. Hardly meaningless from the North, is it.

I'd hardly call a yellow met warning for 2-5cm of snow severe and chaotic. There is nothing overly special about this westerly, it has just been hyped up.

Yes, the uppers are slightly colder than would normally be the case but the Atlantic will moderate these which is why most areas will still make it above freezing especially outside of any showers. 

[frosty ground]

1 hour ago, mulzy said:

Yep, the NWP all trending the wrong way. To be honest the Westerly “blast” was never going to deliver much here. Temps of 8C with a breeze - yippee!! Just disappointed with the medium term outlook now - the dreaded AZH showing its hand.

Yes there was never really a cold spell for your kocation only ever on FI at 7 days plus away so there can be no shock that there has been a change after all your always telling people not to get sucked in..... i suppouse the only saving grace is that tge cold westerly is going to deliver snow for my location which was predicted almonst 10 days out. Not sure i like the look of the storm either but either a way a vwry wintry week coming up

[shaky]

6 minutes ago, nick sussex said:

What a shocker.

The problem stems from the upstream failure to develop a more coastal low.

Instead phasing takes places further east and the pattern is flatter, downstream you can see the impact . 

No decent Atlantic ridge .

The ECM is the best of a poor bunch and has the most amplified pattern. It still goes pear shaped later but at least given the timeframes could improve .

Unfortunately the trend is against us.  I would be surprised if the ECM lasted the day.

The GFS has got even flatter overnight and the UKMO jumps ship aswell.

The shortwave low track which deepens is symptomatic of the flatter upstream pattern with it’s more northerly track.

Overall a hugely disappointing start to the day.

 

 

I hate to be negative mate but i really do think its game over!!as you say its all to with the shortwave and i expect that to track further north aswell!!it crazy to think something so small like that can have an impact and bodge up up everything in the mid to long term for us!!worse thing is i cant remember the last time we had something like this but to benefit us instead for once in our lives!!

[swfc]

Not much to add really after this mornings musings so far.coldish week coming up with the north and west catching the majority of any wintryness. Just seen the lateat beeb forecast for mid week  regarding the deep low and any sleet~snow on its northern edge into scotland.unsettled week without doubt but nothing out of the ordinary imo.mayby in future some of the newer members mighnt do well not to take notice of charts ete beyond 5-7 days.yesterdays gfs 12z induced 1947 comments and look where the outlook "yet to varify"is this morning.spanners a plenty still to be thrown in given the complexity ie the systems over the esb and canada ete.have a good sunday folks

Edited January 14, 2018 by swfc

[Nick F]

'If it can go wrong it will go wrong' it seems on our small island, though there is perhaps underlying cause to our plight at the moment, i.e. any amplification the models have been factoring in until recently is fighting against La Nina forcing which is causing a typically erratic upper flow pattern which is further north than we'd like and also 'warmer phases' of MJO, which will flatten out the pattern. 

MJO phase 4 composite seems to have reasonable comparisons to the EC/GFS op days 8-10 H500 pattern, which is not a great look if you want prolonged cold

IMO until we get out these warmer phases and strike lucky with the wave amplitudes, then it may be a struggle to get any sustained cold pattern locked in as the models were showing, when there was, for a time, a signal to build heights around Iceland to allow a Nly or even NEly flow. Still hints for a late winter SSW too, but if it happens it may take time to propagate to the trop and we could be looking at Feb.

Still chance the models maybe being to flat / progressive with the flow late week onwards, but given the background drivers, the morning's output is not a surprise.

Edited January 14, 2018 by Nick F

[nick sussex]

Just now, shaky said:

I hate to be negative mate but i really do think its game over!!as you say its all to with the shortwave and i expect that to track further north aswell!!it crazy to think something so small like that can have an impact and bodge up up everything in the mid to long term for us!!worse thing is i cant remember the last time we had something like this but to benefit us instead for once in our lives!!

The shortwave by itself isn’t the issue . It’s the upstream pattern between T120hrs and T144hrs hrs.

What we saw was the models messing around with how low pressure develops over the ne USA.

We saw a trend towards the original idea of the ECM with the coastal low. Yesterday we started seeing the low further away from the coast with less favorable phasing with the shortwave which originated in the Pacific .

This resulted in less Atlantic ridging .

The ECM is the best today upto T168 hrs because you’ll see it at least phases with one main low pressure system however the others are now developing a messier system.

Give it tonight but the overnight trends aren’t good.

[snowbunting]

Two things from the model tuns this morning...

1. The low expected around this thursday is most likely going to take a more Nly track... 

2. After 150hrs we have loads of ensemble runs supporting the sustained cold conditions. 

[Summer Sun]

UKMO has a westerly at D6 by D7 is gets pushed south again allowing some colder air to filter back in from the north

 

[Summer Sun]

00z mean remaining close to average from the 22nd ish control clearly gone off on one

Still plenty of scatter both mild and cold so anything can happen in the coming days

[terrier]

Wow what a turn around on the models this morning. The ukmo looks awful. The pub run always seems to pick up a new signal and then the rest of the output follows. Next week can be summed up in two words wet and wind. As Steve murr allied to nothing to see here once again. Seems to be the story of the models this year. 

[offerman]

23 minutes ago, snowbunting said:

Two things from the model tuns this morning...

1. The low expected around this thursday is most likely going to take a more Nly track... 

2. After 150hrs we have loads of ensemble runs supporting the sustained cold conditions. 

Nice post snowbunting. 

 

Classic examples of too much excitement too far out and the charts letting people down as the event draw nearer. 

 

When will folks learn not to get their  aspirations and excitement up too much beyond 3-4 days. 

Time and time again it happens with the charts . Most of the time to the let down side for collies . 

I love the cold and snow. I too once always looked too far ahead getting excited only to be let down. I see so many others doing the same. You can’t predict the weather so far out. Just look to charts 3-4 days within but even these can change but should be more reliable timeframe as rule of thumb. 

[That ECM]

2 minutes ago, offerman said:

Nice post snowbunting. 

 

Classic examples of too much excitement too far out and the charts letting people down as the event draw nearer. 

 

When will folks learn not to get their  aspirations and excitement up too much beyond 3-4 days. 

Time and time again it happens with the charts . Most of the time to the let down side for collies . 

I love the cold and snow. I too once always looked too far ahead getting excited only to be let down. I see so many others doing the same. You can’t predict the weather so far out. Just look to charts 3-4 days within but even these can change but should be more reliable timeframe as rule of thumb. 

Indeed. See you all later so we can discuss an obscure model showing snow out in the far reaches of FI because that's what we do.  

[Paul]

I've moved some posts over into the banter thread, so please look in there if you're wondering about a missing post. As ever, please use that thread for moans, ramps and emotional reactions to the models. 

https://www.netweather.tv/forum/topic/86721-model-moans-ramps-and-banter/

 

[Daniel*]

14 minutes ago, terrier said:

Wow what a turn around on the models this morning. The ukmo looks awful. The pub run always seems to pick up a new signal and then the rest of the output follows. Next week can be summed up in two words wet and wind. As Steve murr allied to nothing to see here once again. Seems to be the story of the models this year. 

White and windy for some areas! Nothings really changed in terms of PM cold spell, yes a storm may interrupt the cold flow however it quickly moves back in. UKMO day 7 has it cold again..

A lot going on high uncertainty from the weekend.

[MR EXTREMES]

49 minutes ago, nick sussex said:

What a shocker.

The problem stems from the upstream failure to develop a more coastal low.

Instead phasing takes places further east and the pattern is flatter, downstream you can see the impact . 

No decent Atlantic ridge .

The ECM is the best of a poor bunch and has the most amplified pattern. It still goes pear shaped later but at least given the timeframes could improve .

Unfortunately the trend is against us.  I would be surprised if the ECM lasted the day.

The GFS has got even flatter overnight and the UKMO jumps ship aswell.

The shortwave low track which deepens is symptomatic of the flatter upstream pattern with it’s more northerly track.

Overall a hugely disappointing start to the day.

 

 

So would suggest that last night's states assessment was well of the mark.

But then again I expect they were seeing the model data and for few days cross model agreement,

But I hope, that maybe lots of atmospheric background noise because of other forcings could be a reason behind the switch.

Although the gem was first last night to show the back track.

I think the modelling is struggling with the shortwave storm midweek.

Towel not thrown in yet but if we see continued support for this mornings runs then I'd definitely agree with Steve murr.

This blooming country is a nightmare for true winter weather in the last two decades.

Although frustrating best to keep an open mind.

Eyes down for the GFS 6z

[Northern Sky]

3 minutes ago, Daniel* said:

White and windy for some areas! Nothings really changed in terms of PM cold spell, yes a storm may interrupt the cold flow however it quickly moves back in. UKMO day 7 has it cold again..

A lot going on high uncertainty from the weekend.

Yes that's what I was thinking. Still on course for wintry showers Tues and Wed. Wed evening the storm arrives bringing a brief milder (but potentially very interesting) interlude before the cold PM flow resumes on Thurs again, bringing wintry showers up to at least Saturday. After that there are different options on the table. Could be worse

[MR EXTREMES]

GFS 6z shows that short wave development and it looks like it is further north around northern england into scotland looks to be the modelled track.

Although as Captain shortwave explained there are heights over the pole maybe this is the thorn in our side.

Although the warm sector it don't look awful but certainly not looking like a northerly or northeasterly ATM.

 

Edited January 14, 2018 by MR EXTREMES

[Daniel*]

5 minutes ago, Northern Sky said:

Yes that's what I was thinking. Still on course for wintry showers Tues and Wed. Wed evening the storm arrives bringing a brief milder (but potentially very interesting) interlude before the cold PM flow resumes on Thurs again, bringing wintry showers up to at least Saturday. After that there are different options on the table. Could be worse

I’d still be excited if I was in the north / west. Looks very promising. Changeover to milder Atlantic weather might be snowy too as seen on GFS 00z my feeling is that it is too progressive a breakdown by Saturday. Unfortunately some are falsely putting out next week is going to be a no show just wet! Even I think I’ll see some falling snow down here..

[markw2680]

1 hour ago, shaky said:

I hate to be negative mate but i really do think its game over!!as you say its all to with the shortwave and i expect that to track further north aswell!!it crazy to think something so small like that can have an impact and bodge up up everything in the mid to long term for us!!worse thing is i cant remember the last time we had something like this but to benefit us instead for once in our lives!!

The one thing I hate more than the term upgrade and downgrade is GAME OVER!! There’s days still before Wednesday, Thursday so loads more runs, little changes can turn into big changes down the line. It’s not game over at all it’s the middle of winter and it’s the bloody weather. Hardly a life or death situation. There will be many more changes yet