Chesil View

March 27

What is the average annual rainfall for your area and how much have you had so far this year.

March 8

Just keep twisting the knife winter of 2024 why dont you..

March 3

As usual for the past few months the road to getting any genuine deep cold to the UK is proving a long and tortuous one.

February 27

Ecm has some trough disruption to our west and some cold air coming round the Scandi High at the end.

Only ten days to reel it in.

February 19

Met4Cast

This is so true Met4Cast. And I think why some posters incorrectly poo poo the background signal or global drivers.

On a global scale the UK is tiny and to expect a Pacific based signal like the mjo to be able to forecast snow in Croydon is absolutely ridiculous.

As you say at best they give a broadbrush picture of the probabilities of what regimes may hold sway.

My personal feeling is that CC may probably making things like the mjo composites that we have relied on in the past somewhat less reliable.

Which if anything will make the great work by the likes of Tamara. Blessed weather and yourself among others even more difficult.

Rather like Catacol I am also becoming more convinced that without a proper SSW as opposed to technical SSW any extended or severe winter spells are unlikely to occur.

That is not say to we won't get snowfall even in south but I think what we do get will be shortlived without SSW.

I have not seen a decent depth of settled snowfall here in South Dorset since 31st Jan 2019. I'm sure I will see some more at some point but when? is the 64,000 dollar question.

February 16

Time for me to call it a day for this winter from a southern snow lovers point of view. Its been a frustrating one promising much but delivering very little of substance.

Even the northerly progged around day 10 just means cold wet instead of warm and wet.

The weather will probably continue to take the pee and bring a blizzard in April but I can't be bothered to sit through another 6-8 weeks of daily runs to see great looking synoptics with uppers that won't cut the mustard.

February 14

Eagle Eye That was exactly my point and why I made it with the greatest of respect.

February 14

TEITS

Very true Teits. I think part of the problem is that SSW and the strat has moved into the simplistic media world added to this that we have had two gold standard ssw responses in the relatively recent past Dec 2010 and feb/march 2018. The former providing the coldest Dec in a hundred years and the latter the coldest such spell at thst time of year since 1845 and it is easy to see how everyone gets carried away. Add into the mix biased twitter based commentators and the hype just increases.

Even the oft quoted 66% figure bringing cold to the UK is I feel somwhat disengenuous as a dumping of snow on the usual suspects in Scotland and Northern High ground in England can be classed as bringing cold and snow to the UK.

For me the test of a cold spell (and this is honestly not just because of my location) is if a cold outbreak brings deep cold and /or snow to lowland southern England because then it is out of the ordinary and beyond the realm of a bog standard chilly outbreak with snow on high ground in the usual places.

As you say Tamara's unbiased posts that are made with out a required emotional outcome are valuable in keeping ones feet on the ground although even here Tamara's suggested shuffling hieghts scenario has not really come to fruition either and I say that with greatest of respect because it simply goes to show how ultra sensitive our uk based outcomes are to small changes in the background drivers.

February 14

Weatherman_93

It really isn't that unusual for temps to hit 16c with a longfetch southerly or south-westerly in February. Not common I grant you but not that unusual. we have already hit 15.9 on 3rd.

February 14

It's frustrating being stuck in this holding pattern waiting for possible ssw fallout at the end of the month and into March while the modelling waxes and wanes as to how that may play out.

February 12

Any ridging attempts just getting steam rollered at the moment on the ecm.

February 12

RJBingham

February 12

RJBingham

But not before it had brought me this.

February 12

I think the extended outlook is just the meto covering their backsides regarding possible ssw fallout.

Let's face it pretty much every one on every weather forum knows an ssw is in the offing. If we were perchance to get a major dumping as a result and they hadn't even mentioned colder northerlies or easterlies and the possibility of snow fall on the boundary with milder intrusions they'd get roasted alive in the media.

February 12

Looks like a long drawn out process to get to anything cold. Even if the ecm is on the money. We would still be waiting for that UK high to progress to Scandinavia or retrogress to Greenland /Iceland.

Not impossible given the likely ssw but wait and see.

February 10

An interesting discussion of ideas and thoughts from Matty H. Tamara and Nick F.

I think perhaps what those not familiar the Gsdm tools might be missing and therefore reacting to when things don't come out to give us the emotionally invested result of deep cold or snowfall. Is that like many other forms of science. These tools are also a work in progress in terms of learning and attainment of results.

Tamara to her great credit has often made the point that A plus B doesn't always equal C in this subject. Which can perhaps to the uninitiated seem counter intuitive when describing something as a tool.

It could be argued that if you have a tool like pair of pliers for instance and A is the pushing together of the handles which helps to produce B the bringing together of the grips then surely if the grips don't then grab the object your trying grip (C) then that pair of pliers are a pretty useless tool. And often the answer that comes back as to why the pliers didn't work was because the chisel wasn't on the workbench as well can often just sound like a get out of jail free card.

But the ocean/ atmosphere is so massively dynamic on both horizontal and vertical levels that the simple analogy of the pliers not working is just too simplistic to cover all the nuances and small alterations than can make a huge difference to our tiny corner of the globe.

Surely both nwp and gsdm tools can as Tamara out points be complimentary. My own feeling as very much an amateur trying to understand the nuances of both is that gsdm is not there to tell us if its going to snow in our back yard or country or region. That's nwp's job

Moreover its main use as I understand it at the moment within its current limitations is to give probabilities around which regime in terms of global placement of ridges and troughs may predominate and thus the likelihood of which weather/climate regime may be likely to hold sway over a an area of the globe at a given period even a month or more hence. (I hope I'm not doing it a disservice.)

In conclusion niether nwp or gsdm are the finished article in terms of perfect results ( and indeed may never be) of what many winterwatchers seek and are to a greater or lesser extent somewhat emotionally invested in.

On a personal note I'm just extremely grateful to have access to the wealth of knowledge from those of both nwp and gsdm schools available on this forum and have huge respect for both.

February 10

Lots of really thoughtful posts in this thread making it a really interesting read.

I think the fact that there are just so many variables in the background signals that have to fall into place for the the UK to get deep cold and a winter worthy of the name has always been the problem to overcome (even back in the 60's 70's and 80's when decent winter spells were more common. )

Local records here tell the story snow wise. In the 60-80 s even lowland Dorset could expect a half decent covering in 7 winters on each of the decades. That is now down to three on average. That's is the difference a small rise the mean winter temps has made.

February 10

Nick F

Indeed Nick. I posted something similar a few days ago.

There is quite a dichotomy between what the background drivers can foretell and what many of us seek to find through nwp and being members of this thread.

A great many of us on here are lovers of good old fashioned winter weather and snowfall.

A good number of us are old enough to have had to measure snowfall in feet and inches (even in southern england) not because we're old fashioned but because on a good many occasions those were the units that you could measure it in. Nowadays we're reduced to measuring it in centimetres to try and make whatever we get sound deeper.

We are lucky enough to have some very knowledgeable members who are expert in the interpretation of gdsm. Aam mjo qbo gwo orbit and strat charts etc all of which to a certain extent make up the sum of our dynamic atmosphere and their knowledge is invaluable.

At the same though these tools are at the very best broadbrush in giving some approximate idea of where troughs and ridges may set up on a global scale.

The Dichotomy comes in that many of us would like to get a handle on whether it's going to get very cold or even snow somewhere relatively near our backyard or even in our own half of the country.

All the meteorological acronyms in the world simply can't do that yet. Or at least our interpretation of them can't yet.

Yes a certain mjo phase or gwo orbit or eamt event or combination of them MAY favour high latitude blocking to our north but as we have seen time and time again that doesn't necessarily make it happen in the right place in the real world and even if it does it still remains a lottery as to whether anything remotely wintery reaches these shores.

February 9

Weirdly there is some continuity on the Ecm 0z from last nights 12z in terms of Greenland and the arctic although not quite as out there as last night. Could be some interesting developments over the weekend output I think.

February 8

blizzard81 but will it actually bring deep cold to thr UK. That's the question?

February 7

Laughable continuity on the gfs op.

Going from multiple runs of ultra mild soutwesterlies. To an easterly then a slowly retrogressing UK high.

February 7

minus10

An excellent post and a point well made and one in line with what i feel i have learnt about them over my years on here

in my opinion The back ground drivers which I do believe control the general set up can at best only provide broadbrush picture of where ridges and troughs may set up.

Its easy to get excited when we hear that a certain mjo phase favours Grenland high or Scandi high but worth remembering you can have a high in either of these locations that doesn't advect cold air across our tiny area of the globe.

In fact the vast majority of scand blocking often just holds a trough in position over the UK with wet and mildish weather as a result.

Similarly with Greeland Highs the vast majority are slightly too far west and simply advect arctic air into the mid Atlantic.

There is no doubt in my mind that the background signal make the general broadbrush set up.

But getting deep cold to advect across the UK is down to the very exact positioning and orientation of these Greenie and Scandi Highs and that is the detail the no mjo phase or gwo orbit or qbo or eamt event can yet successfully forecast for such a small island as ours.

So whilst I am always interested to hear from the brilliant experts about the drivers that we are so fortunate to have on this site.

I am also aware, as are they. That those drivers simply cannot tell me if its going to snow in my back yard or even my country.

All they can do is give an idea of where the balance of probabilities may lie in regard to getting the cold to our shores and that is all they can and no more than that.

Original post: https://community.netweather.tv/topic/99814-model-output-discussion-22nd-jan-2024-onwards/?do=findComment&comment=5032533

February 7