[Scottish weather discussion - Spring 2023/24]

 Ross B

The worst of the second batch missing me to the south just by the hair of a baw

[Scottish weather discussion - Spring 2023/24]

Next band getting its act together for round 2 

[Scottish weather discussion - Spring 2023/24]

Proper squall, well highlighted on the radar too 

 

 

 

Managed to catch the thunder snow in this second video albeit the tail end of the longest thunder rumble known to man

 

 

End result until the next batch moves in 

 

[Scottish weather discussion - Spring 2023/24]

-10c after a few inches of snow will do me fine 

[Scottish weather discussion - Spring 2023/24]

Not got a lot of time to look but I reckon an Amber will be dished out for tomorrow for the higher ground around the centre of the central belt and possibly extending north and south to cover the uncertainty of the track but the timing of it and the potential probably merits an amber

[Scottish weather discussion - Spring 2023/24]

3 hours ago, johncam said:

We have went from-6 to -2 and no   ice days now , aw well mabye next time 

Wait til you see this John, you'll pish your frillies ..... the ice days are coming back 

Coatbridge ...

-5C's in there for minima aswell plus 2 ice days over the next 4 days for you. MetO generally slightly over estimates temps too, especially the night time minima temps. 

[Scottish weather discussion - Spring 2023/24]

A lot more pink than I expected to see tbh 

[Scottish weather discussion - Spring 2023/24]

Warning area to the south of Scotland extended northwards 

Interesting

 

Could give a good a fee cm before turning back to rain 

 

 

 

[Model discussion highlights]

17 minutes ago, Harsh Climate said:

It's already happening and in full flow by Sunday!

We are seeing an almost immediate impact due to the Canadian Warming and a few various other factors this is why we may not need a full SSW for Cold/Snow Nirvana Mid January, we might just get away with it but we are relying on pieces of the jigsaw coming together in just the right places.

That chart you're showing is the warming taking place higher up in the strat .... and when you look at the mean windspeed up top for today/tomorrow, they are at the peak. 

The reduction in the zonal winds doesn't bottom out until the 6th of January, again bearing in mind this is up top. There's no way that the great reduction of zonal winds can imprint its effects on the trop on Sunday when it's still 1 week prior to the reduction in windspeed taking place. Following on from that, even when the windspeed reduction takes place up top, there is going to be a respective response time, with even a QTR taking some time to filter down to the trop. You can't have an instantaneous response, it just isn't possible. There needs to be a degree of time for the effects to filter down to the trop. 

Original post: https://community.netweather.tv/topic/99584-model-output-discussion-into-winter/?do=findComment&comment=4987631

[Model Output Discussion - Into Winter]

Nice to have healthy debate and conversation for once with no sniping and all views being considering and discussed. How it should be! @Mike Poole @Met4Cast @Harsh Climate

[Model Output Discussion - Into Winter]

4 minutes ago, Harsh Climate said:

Thanks. To be fair though doesn't a strat warming usually take 3/4 weeks?? What I am saying it will happen a lot faster this time around due to the other factors I highlighted (Canadian warming etc.).

I think that was part of the debate on the strat thread to be honest, with having a -NAO already in place at the time of a SSW, whether this led to a compounding of the -NAO signature with a quicker downwelling with less atmospheric resistance. But a downwelling into the trop can never be guaranteed either with some SSW's in the past failing to downwell and imprint on the trop at all. 

In terms of what factors can speed up or hinder a trop response, the strat guys will be able to enlighten far better than I will but my understanding is that a QTR would be considered to be inside the 2 week mark and a more generic response being beyond the 2 week mark. 

There is no A+B=C when it comes to the strat though, it's a developing science in its absolute infancy which is where the interesting differing perspectives come from. There can't be any guarantees at this stage in terms of downwelling or what response we will achieve if any, whether or not we've had a previous Canadian warming. That's where the interest and intrigue comes from, more especially as we head into weeks 2/3/4 of January to see how the trop is effected by the reduction of zonal winds. 

As others have said though, regardless of not achieving a technical SSW, it doesn't look like we'll be far off in terms of zonal wind speed so there will still be a profound effect if it downwells successfully. 

[Model Output Discussion - Into Winter]

17 minutes ago, Harsh Climate said:

It's already happening and in full flow by Sunday!

We are seeing an almost immediate impact due to the Canadian Warming and a few various other factors this is why we may not need a full SSW for Cold/Snow Nirvana Mid January, we might just get away with it but we are relying on pieces of the jigsaw coming together in just the right places.

That chart you're showing is the warming taking place higher up in the strat .... and when you look at the mean windspeed up top for today/tomorrow, they are at the peak. 

The reduction in the zonal winds doesn't bottom out until the 6th of January, again bearing in mind this is up top. There's no way that the great reduction of zonal winds can imprint its effects on the trop on Sunday when it's still 1 week prior to the reduction in windspeed taking place. Following on from that, even when the windspeed reduction takes place up top, there is going to be a respective response time, with even a QTR taking some time to filter down to the trop. You can't have an instantaneous response, it just isn't possible. There needs to be a degree of time for the effects to filter down to the trop. 

[Scottish weather discussion - Spring 2023/24]

2 hours ago, Kirkcaldy Weather said:

Jan week 1 is giving me big February 2021 deja vu,

 

I love it when you talk dirty to me  

Im ready for a Feb 2021 re-run

 

 

[Model discussion highlights]

1 hour ago, TillyS said:

This is as zonal as I can ever recall for this time of year. We are in the midst of an Atlantic battering  .

 

47 minutes ago, TillyS said:

Thanks for your realism

 

The absence of any useful northerly blocking is incredible tbh. There’s usually something around Greenland, Iceland, Svalbard, Scandinavia at this time of year.

Come on! You really can't be serious with this? Pessimism must be high to conjur up statements like this but unfortunately they just aren't true. 

For balance of presenting fact as opposed to dramatic headline grabbers .... here is yesterday's verified chart: 

 

 

Now compare that with a genuine pessimistic chart for this time of year, aka 2004: 

 

You can see the cause for pessimism diminishes somewhat.... and further to that, we have a more amplified MJO, phase 8/1, a pending significant weakening of the strat, and a host of other favourable teleconections which I won't go in to analyse given the great job that others do so well to explain to everyone and have been giving a running commentary on. Point being, there is plenty reason for optimism beyond the 7-10 range, its not your 2004 picture painted above. 

To keep the balance of realism for maybe newer members (as I suspect the seasoned will know that you threw a few statements out with no rationale, or indeed, maybe for the controversy) ....

Here are 5 of the last 8 years for this same time of year: 

 

And here is the 3 remaining years of the last 8 years which have a slightly better viewing albeit, still don't show up the "abundant end of December northern blocking" 

 

Model fatigue can be a funny thing, but when you go back to looking for the basics, eg a roaring PV over Greenland, strong azores high or iberian high with a strongly positive NAO, or indeed strongly positive AO, a cold strat with zero warmings, an MJO in the COD and so on.... if you can tick all those boxes with no change in the forecast, only then will your statements hold credence. 

I envy the newer members this winter more than probably any before because the sheer amount of false factless based information being branded about this winter makes for a difficult read and gives a very poor foundation for learning. 

Original post: https://community.netweather.tv/topic/99584-model-output-discussion-into-winter/?do=findComment&comment=4985691

[Model Output Discussion - Into Winter]

1 hour ago, TillyS said:

This is as zonal as I can ever recall for this time of year. We are in the midst of an Atlantic battering  .

 

47 minutes ago, TillyS said:

Thanks for your realism

 

The absence of any useful northerly blocking is incredible tbh. There’s usually something around Greenland, Iceland, Svalbard, Scandinavia at this time of year.

Come on! You really can't be serious with this? Pessimism must be high to conjur up statements like this but unfortunately they just aren't true. 

For balance of presenting fact as opposed to dramatic headline grabbers .... here is yesterday's verified chart: 

 

 

Now compare that with a genuine pessimistic chart for this time of year, aka 2004: 

 

You can see the cause for pessimism diminishes somewhat.... and further to that, we have a more amplified MJO, phase 8/1, a pending significant weakening of the strat, and a host of other favourable teleconections which I won't go in to analyse given the great job that others do so well to explain to everyone and have been giving a running commentary on. Point being, there is plenty reason for optimism beyond the 7-10 range, its not your 2004 picture painted above. 

To keep the balance of realism for maybe newer members (as I suspect the seasoned will know that you threw a few statements out with no rationale, or indeed, maybe for the controversy) ....

Here are 5 of the last 8 years for this same time of year: 

 

And here is the 3 remaining years of the last 8 years which have a slightly better viewing albeit, still don't show up the "abundant end of December northern blocking" 

 

Model fatigue can be a funny thing, but when you go back to looking for the basics, eg a roaring PV over Greenland, strong azores high or iberian high with a strongly positive NAO, or indeed strongly positive AO, a cold strat with zero warmings, an MJO in the COD and so on.... if you can tick all those boxes with no change in the forecast, only then will your statements hold credence. 

I envy the newer members this winter more than probably any before because the sheer amount of false factless based information being branded about this winter makes for a difficult read and gives a very poor foundation for learning. 

[Scottish weather discussion - Spring 2023/24]

Genuinely unbelievable how this has remained a yellow warning through-out. Its 100% a high amber, verging on red if it was down south. 

Unfortunately round 2 appears to be inbound aswell following a very brief lull. 

[Model Output Discussion - Into Winter]

54 minutes ago, TSNWK said:

06z gfs should give a clue on that.. look at jetstream and heights post vortex plunge end of next week

 

52 minutes ago, northwestsnow said:

Without any Blocking highs at northerly latitudes polar maritime attacks will almost always end with azores heights ridging into Europe via Spain.

The firm favourite is then an ugly NH profile.

Hopefully background drivers save the day later down the line..

In the meantime I'm hoping for a decent cold blast 

This is my point, the basis for most people for this 'mild and wet for the next 3 weeks' narrative is mostly being pushed by model output alone. 

It's far too turbulent to be basing a forecast for the next few weeks off the back of a closer range forecast that hasn't verified yet. 

As stated by someone above, beyond 144 at the moment is up for grabs. There was next to no lead time for the current forecast of the potentially active/ possibly colder with some snow etc spell of weather for next week, to show its hand. Literally the day before it started to materialise people were calling for a very mild Xmas period, not a sniff of colder weather until next year etc. ...... who have conveniently not commented since  

[Model Output Discussion - Into Winter]

45 minutes ago, weathercold said:

Morning, as expected 24 hours on any cold/wintry looking charts seems to be reducing rapidly.

Whilst not wanting to be that person who said ‘told you so’ I really couldn’t see the over egging optimism of some yesterday.

There is no concrete supijuuport for anything wintry for most of the UK, in fact quite the opposite. I’m not even confident hills up north will see much if anything over the Xmas period.

A chilly few days possible, nothing more than that and temps around average for Dec UK wide.

Some calling a cold and wintry Jan are making a brave call, fair play if correct. I’m not seeing much evidence to support this currently. 
 

Taking into account all available info, it’s looking very Atlantic driven through to the end of the month. A rather mild and wet Xmas period is a sound punt right now.

WC

Why was it expected to reduce 24 hours later? 

And what's all the available info you're referring to for the next 2 and a half weeks to be Atlantic driven? 

[Model Output Discussion - Into Winter]

29 minutes ago, knocker said:

I don't think that is what he is saying. But in any case  it is not that easy to evaluate the probable influence of the the forecast background signals on the Atlantic and European weather as some on here make out. But having said that they should always be taken into account along with  a keen scrutiny  of the model outputs.

I've maybe picked it up wrong but what I'm reading is that someone who thinks its a mugs game to be trying to formulate a forecast based on background signals or teleconnections, but iinstead is looking across model suites at this given time and affirming that it is giving credence to wet and mild for the next 3 weeks until the months end? 

Basing an outlook solely on model output, especially one that hasn't happened yet is not a way to back up an argument. More than happy to listen to views or opinions with a rationale behind them, be it cold, mild or anything in between 

[Model Output Discussion - Into Winter]

25 minutes ago, adamgooner said:

Firmly believe we are looking at a wet and v mild run up to Xmas and personally until end of year. Background signals don’t guarantee you anything and these current charts show you just that - pinning your hopes on these alone is a mugs game sadly.

I think you'll probably find that calling wet and mild until the end of the year when it's far outside even the depths of FI on the models is more of a 'mugs game' 

Essentially what you've said is: ignore background signals, have a look at what you see in the models, take that as gospel and run with the thought ls that it'll continue beyond the forecast period exactly the same. 

Nothing can be taken as gospel just now, not when the extent of the MJO amplification can't be pinned down yet with conflicting forecasts. There's no doubt that whatever verifies with the MJO in terms of amplification will have a knock on effect. 

MJO aside, it's again subjective to location, in terms of how wet and how mild the near term gets but I'd not be hanging my hat on it continuing until the end of the year, just as much as I'd not be hanging on a colder outlook. There's plenty water to pass under the bridge in the next week or so. 

[Scotland Weather discussion]

Well I wasn't expecting much being so far to the east of the warning but I'll take it. Looks like a bit more to come yet judging from the radar too. Almost looks like the much rarer Clyde - Forth streamer

 

[Scotland Weather discussion]

1 hour ago, Kirkcaldy Weather said:

Eyes switch towards around Dec 4th

 

Don't switch your eyes just yet.......

The Eastern half of the central belt might just be in for a wee surprise tonight. 

The direction of flow for the showers has been gradually swing round from the NE over the last few hours. 

2 hour difference is clear : 

Just needs to swing a wee bit more before there on a good bearing for coming into the central belt and there plenty shower activity showing in the North Sea the for it: 

The overall strength of flow isnt drastic so showers are fizzling out fairly quickly as they push inland but some small continuing adjustments could see some Eastern parts of the central belt getting a covering  

[Scotland Weather discussion]

The latest UKV highlighting the narrative of tonight quite well and showing the differences from yesterday morning: 

[Scotland Weather discussion]

39 minutes ago, Big Gally said:

I’m still optimistic. straight easterly’s would be better but who knows streamers  crop up out of nowhere.

The direction is important though and the flow strength because without a strong flow, any showers that do form will fizzle out before making it far inland and if the direction of flow isn't enough East to West then there won't be anything blowing through the central belt. The length of the draw is also important as is the upper air temp (850hpa). 

That doesn't rule out the likes of East Lothian getting a better feed of showers ofcourse with how things look at present. 

As things stand, any tracks of showers look like setting up more over Eastern and south-eastern England with our window for showers potentially driving inland looking much shorter, however the latest MetO charts do seem to provide a slither of hope for a small window of chance, but not your classic streamers, more akin to standard showers. 

Further north still looks to do quite well and potentially Eastern borders depending on how things develop but it's definitely no outstanding lake effect snow / streamer synoptics just yet. 

Here's the latest Met O chart for Thursday: 

 

And if you compare that with your more classic streamer scenarios of the past 2010, 2018 and for me personally feb 2021, you can see the areas we're lacking synoptically at the minute for such a set up: 

[Scotland Weather discussion]

Well the thought was nice but the continuing southward corrections will likely remove the notion of any snow showers piling through the central belt. Maybe the odd shower but with the flow now looking much slacker in Scotland due to the southerly track of the low, coupled with a sharper orientation to the wind flow i.e much more NE than E, it seems a stick on now that we'll have primarily dry and cold conditions for Thursday and Friday, unless any features crop up or there is a change in the modelled output of Thursday's Low. 

 

Although just as I typed that, the latest MetO run depicts that all is not lost, I might backtrack my backtrack by tomorrow