Model output discussion - into the last third of January

[MATTWOLVES 3]

Positive signs for February perhaps! Just to take a look at a few ens that bring some interest moving forward! Lots of options as always with the GFS ens...

EC data also hinting at further warming events of the strat in the weeks ahead..coupled with perhaps  movement of the MJO cycle into perhaps 6/7. Im not quite so sure of the la Nina cycle bringing that milder more Atlantic dominated spell late Winter..perhaps to the Eastern States,but not to our shores..Feb could be very interesting this year...im certainly not seeing a 2019 re run..with record warmth..Thank god.

Chart on strat data courtesy of Marco P.

Edited January 19, 2021 by MATTWOLVES

[Frosty.]

The GEFS 6z mean indicates a general return to colder conditions later this week continuing into early next week but then a milder trend / spike towards the end of Jan...but then another return to colder conditions early next month...still hoping the ssw will eventually bear fruit for our little dot on the map!!!!!.

Edited January 19, 2021 by Jon Snow

[jimbo36]

1 hour ago, Frosty Winter said:

Interesting, I’ve also been monitoring the extended GFS control runs recently and there has been a relatively consistent signal for northern blocking to re-establish itself by mid-February. This run is from yesterday and I’m still waiting to see today’s. Of course it may still come to nothing but it’s something to watch nonetheless.

i haven't posted for a few years after annual snow disappointments but would just like to say whilst recuperating that the 2nd image shows a nice pair of Y fronts in the centre :-)

[MAF]

yeah, its known as a Y block, as opposed to an Omega one

[Jason M]

Slightly different take on the GEFS to others in here. I tend to scan quickly through all 30 at 192, 240, 384 hours  (I admit I look a bit more at interesting ones!). Not a foolproof method by any means but it has generally served me well.  I don't feel much benefit in looking much before 192 hours at present as I feel (maybe wrongly) that the general pattern is locked anyway at present before that point (as it seems to me to be 90% likely that we reach day 10 with heights in or around Iberia).

My take on them is that southern heights remain dominant out beyond ten days. From day 13 onwards they are pretty much 'scatter'. There are some cold charts in amongst them but nothing that would suggest a Beast or anything like. The problem with looking at the odd 'chart' that shows the easterly is that it doesn't illustrate the fact that its a 48 hour event at best. As the GEFS suite progresses it gets more mobile and there is not much evidence of any tendency towards northern heights. 

Based on what I'm seeing my main observations would be

1. Little chance of deep cold in the UK out to day 14 (maybe just a fleeting 24-48 sideswipe is just about possible - 20% chance?)

2. Little evidence of northern blocking (seems nearly impossible now to get this in mid winter). Without that a lengthy cold spell is difficult to achieve.

3. Pattern becoming slowly more zonal (albeit it will feel like its zonal at the surface anyway through much of the period)

As you would expect across 30 GEFS there are odd charts that show heights in better areas, but nothing convincing or that doesn't just look like random scatter. the longer term trend towards mobility is tempered a bit by the fact that the runs will tend naturally to climatology over the longer term. As said above, I'm seeing nothing at present to suggest a significantly cold or lengthy cold spell. A 'bog standard' type of cold spell is possible still though.

I'm seeing nothing to suggest the output is struggling with the SSW. At this stage the opposite seems true to me (although others might perceive differently).

[mountain shadow]

2 minutes ago, Jason M said:

Slightly different take on the GEFS to others in here. I tend to scan quickly through all 30 at 192, 240, 384 hours  (I admit I look a bit more at interesting ones!). Not a foolproof method by any means but it has generally served me well.  I don't feel much benefit in looking much before 192 hours at present as I feel (maybe wrongly) that the general pattern is locked anyway at present before that point (as it seems to me to be 90% likely that we reach day 10 with heights in or around Iberia).

My take on them is that southern heights remain dominant out beyond ten days. From day 13 onwards they are pretty much 'scatter'. There are some cold charts in amongst them but nothing that would suggest a Beast or anything like. The problem with looking at the odd 'chart' that shows the easterly is that it doesn't illustrate the fact that its a 48 hour event at best. As the GEFS suite progresses it gets more mobile and there is not much evidence of any tendency towards northern heights. 

Based on what I'm seeing my main observations would be

1. Little chance of deep cold in the UK out to day 14 (maybe just a fleeting 24-48 sideswipe is just about possible - 20% chance?)

2. Little evidence of northern blocking (seems nearly impossible now to get this in mid winter). Without that a lengthy cold spell is difficult to achieve.

3. Pattern becoming slowly more zonal (albeit it will feel like its zonal at the surface anyway through much of the period)

As you would expect across 30 GEFS there are odd charts that show heights in better areas, but nothing convincing or that doesn't just look like random scatter. the longer term trend towards mobility is tempered a bit by the fact that the runs will tend naturally to climatology over the longer term. As said above, I'm seeing nothing at present to suggest a significantly cold or lengthy cold spell. A 'bog standard' type of cold spell is possible still though.

I'm seeing nothing to suggest the output is struggling with the SSW. At this stage the opposite seems true to me (although others might perceive differently).

That seems a fair summary Jason. The SSW does not look like delivery anything deep and cold which is probably why this thread has died a death.

Seems we are now waiting for a favourable MJO towards the end of February into March to deliver along with a final Strat warming may deliver but of course by then the days are getting longer and the sun stronger.

 

[Guest]

Looks like a very uninspiring set of ensembles for the south for the rest of the month. Certainly chilly at times through the weekend however nothing particularly cold, in fact even through the weekend 6-8C looks likely on the south coast. 

 

 

 

[Jason M]

1 minute ago, mountain shadow said:

That seems a fair summary Jason. The SSW does not look like delivery anything deep and cold which is probably why this thread has died a death.

Seems we are now waiting for a favourable MJO towards the end of February into March to deliver along with a final Strat warming may deliver but of course by then the days are getting longer and the sun stronger.

 

Yep, agree with this. I always tend to thing that the period for the gold plated midwinter cold spell is from last 10 days of Dec through to second week of Feb. After that solar input increases very quickly and whilst still perfectly possible to get very cold weather at the back end of Feb its rare for snow to stick around for long.

[MAF]

so, here's a question I may have asked before. And hopefully model related. Does anyone ever look at a day 10 chart and then when day ten comes along compare it with the predicted chart for that day?

It would be really interesting as to the percentage of correctness a day 10 chart gives, say, over a month for example. 

As some may know, I don't give much credence to anything past 5 days, and sometimes even three days ahead. so would love to see some percentages of past those days that a model has predicted correctly, albeit, even a close semblance of the 10th day that was forecast.

[chris55]

Saturdays runner is a chance for some places in the south to seem the first snowfall of the winter.

Track and intensity are still very uncertain, and we'll need to wait a few more days to firm up on details, could well miss us altogether!! But seeing as the chance is there its something worth following over the next few runs. We need to see it develop as it moves east spinning up momentum to pull it further north into the UK.

EC tracks it across the south Saturday with main snow risk to the south east.

GFS operational 6z takes it into northern France.

UKMO doesn't really develop it, keeping it well south.

 

P22 on GFS ensembles is a good scenario with 20 cm for Westcountry and 10cm for London, highlighting a swath of southern England getting snowfall.

Snow depth charts for London show the risk of the system delivering snow, but the mean also shows confidence is very low with only 6-7 members bringing worthwhile amounts.

 

Overall, something to keep an eye on, but not to get to excited about at this point

 

[WINTRY WALES]

There are models which are pointing towards a favourable Feb. Something to pin our hopes on. For us down south it’s been so frustrating after all the hope for the last third of Jan on. I suppose many parts of Europe have felt the benefits of the SSW....just unlucky for us southerners ....even more so when places like Madrid which is well south of us can even get a Hammering of the white stuff!

[egret]

7 minutes ago, MAF said:

so, here's a question I may have asked before. And hopefully model related. Does anyone ever look at a day 10 chart and then when day ten comes along compare it with the predicted chart for that day?

It would be really interesting as to the percentage of correctness a day 10 chart gives, say, over a month for example. 

As some may know, I don't give much credence to anything past 5 days, and sometimes even three days ahead. so would love to see some percentages of past those days that a model has predicted correctly, albeit, even a close semblance of the 10th day that was forecast.

I haven’t done as you describe but it is very tempting.

I sometimes wonder if the best way to forecast at ten days out is to go for the opposite of what the charts are predicting!!

just a brief comment on the ‘mid February is end of real winter’ thinking.

whilst that is probably true for most of U.K., down here on the South Coast our best snowfalls are commonly at the end of February or even March. I put that down in part to the sea being at its coldest at that time of year, despite the sun being much stronger.

I like others am surprised and perhaps a tad disappointed that the SSW has not resulted in easterlies showing by now in the models for the end of January.

 

 

 

[Guest]

38 minutes ago, Jason M said:

Slightly different take on the GEFS to others in here. I tend to scan quickly through all 30 at 192, 240, 384 hours  (I admit I look a bit more at interesting ones!). Not a foolproof method by any means but it has generally served me well.  I don't feel much benefit in looking much before 192 hours at present as I feel (maybe wrongly) that the general pattern is locked anyway at present before that point (as it seems to me to be 90% likely that we reach day 10 with heights in or around Iberia).

My take on them is that southern heights remain dominant out beyond ten days. From day 13 onwards they are pretty much 'scatter'. There are some cold charts in amongst them but nothing that would suggest a Beast or anything like. The problem with looking at the odd 'chart' that shows the easterly is that it doesn't illustrate the fact that its a 48 hour event at best. As the GEFS suite progresses it gets more mobile and there is not much evidence of any tendency towards northern heights. 

Based on what I'm seeing my main observations would be

1. Little chance of deep cold in the UK out to day 14 (maybe just a fleeting 24-48 sideswipe is just about possible - 20% chance?)

2. Little evidence of northern blocking (seems nearly impossible now to get this in mid winter). Without that a lengthy cold spell is difficult to achieve.

3. Pattern becoming slowly more zonal (albeit it will feel like its zonal at the surface anyway through much of the period)

As you would expect across 30 GEFS there are odd charts that show heights in better areas, but nothing convincing or that doesn't just look like random scatter. the longer term trend towards mobility is tempered a bit by the fact that the runs will tend naturally to climatology over the longer term. As said above, I'm seeing nothing at present to suggest a significantly cold or lengthy cold spell. A 'bog standard' type of cold spell is possible still though.

I'm seeing nothing to suggest the output is struggling with the SSW. At this stage the opposite seems true to me (although others might perceive differently).

Thank you Jason. A very balanced review of the models.

[SLEETY]

39 minutes ago, MAF said:

so, here's a question I may have asked before. And hopefully model related. Does anyone ever look at a day 10 chart and then when day ten comes along compare it with the predicted chart for that day?

It would be really interesting as to the percentage of correctness a day 10 chart gives, say, over a month for example. 

As some may know, I don't give much credence to anything past 5 days, and sometimes even three days ahead. so would love to see some percentages of past those days that a model has predicted correctly, albeit, even a close semblance of the 10th day that was forecast.

Wester history Posts the day 10 charts then reality and the difference is normally massive lol, although occasionally one of the models flukes it and shows  something fairly similar. 

Hoping the gfs green line is the trend setter on the ensembles, minus 15  upper air  would mean snow for everyone and not marginal rubbish, wish I could find the permutation.

Can anyone post it? 

Edited January 19, 2021 by SLEETY

[MAF]

3 minutes ago, SLEETY said:

Wester history Posts the day 10 charts then reality and the difference is normally massive lol, although occasionally one of the models flukes it and get something fairly similar. 

Hoping the gfs green line is the trend setter on the ensembles, minus 15  upper air  would mean snow for everyone and not marginal rubbish, wish I could find the permutation. 

and hence my belief that anything posted looking beyond 3-5 days is like looking at fools gold  

However, and using a much quoted phrase on here, it would be nice to "verify" the findings of others

Edited January 19, 2021 by MAF

[icykev]

Id say it was p9 sleety. . .

Pert 1 looks good too, thers a few in the ensembles.

Control.

[mushymanrob]

55 minutes ago, MAF said:

so, here's a question I may have asked before. And hopefully model related. Does anyone ever look at a day 10 chart and then when day ten comes along compare it with the predicted chart for that day?

It would be really interesting as to the percentage of correctness a day 10 chart gives, say, over a month for example. 

 

The only ten day charts i take any notice of are the ones that the NOAA anomaly charts support, they usually turn out to be pretty accurate, but not always.

[MAF]

3 minutes ago, mushymanrob said:

The only ten day charts i take any notice of are the ones that the NOAA anomaly charts support, they usually turn out to be pretty accurate, but not always.

again, forgive me if this is not model discussion Mods; 

So as a percentage you would give the NOAA charts an above 50% rating. And thats what i am asking everyone here, how reliable would you give a winter model a rating. Obviously other seasons may be easier to model, but it seems winter is the most unreliable season to even try and predict past 5 days. 

basically, it boils down to me wondering "why are you looking so far ahead?" when even tomorrow might not turn out to be as forecast. And, yes, i totally agree that an answer to that question might be that 'its the fun of the chase' And i also am a person of belief that 'each to their own' is how things should be  

[winterof79]

06z Euro4 changed again southward

weather model euro4 h model - united kingdom - rain/snowfall [base + 1] - loop | weatheronline

WWW.WEATHERONLINE.CO.UK

---

Weather for UK, Ireland and the world. Sailing, Marine Weather, Weather maps, radar, satellite, climate, historic weather data, information about meteorology...

 

[Timmytour]

1 hour ago, MAF said:

so, here's a question I may have asked before. And hopefully model related. Does anyone ever look at a day 10 chart and then when day ten comes along compare it with the predicted chart for that day?

It would be really interesting as to the percentage of correctness a day 10 chart gives, say, over a month for example. 

As some may know, I don't give much credence to anything past 5 days, and sometimes even three days ahead. so would love to see some percentages of past those days that a model has predicted correctly, albeit, even a close semblance of the 10th day that was forecast.

I would not expect most to have it spot on, near even be close to it, but I suspect bar the odd run, especially the ones showing narnia, the type of weather they predict are not too far off.  That said, if our type of weather were the points of a compass, pretty much 340/360 would bring us mild wet weather this time of year. So the models can direct us to the wrong point on a compass, but the look up for it delivers the same result in terms of weather anyway!

I see some talking about March holding out hope for us. Just from a historical point of view I can't see this happening. Cold Marches for me happen on the back of a winter where there have been at least spells of easterlies in the preceding months.  I don't think this winter qualifies.   In addition we are currently living in what is perhaps a unique period in time in history for the UK when it can be said our coldest month in the last ten years was not a December, a January or a February, but a March!  It's a pretty rare thing for a March just to be colder than any of the three preceding months.  This century has so far delivered us a December and a March colder than any from the last century.  January looks like ending up pretty nondescript in CET terms.  A February colder than any of the last century would be lovely, but I would settle for the coldest one for 30 years!

Edited January 19, 2021 by Timmytour

[Battleground Snow]

Icon a little deeper and further north with Saturday system, a few people might at least see falling snow in the far south

 

[goosey007]

23 minutes ago, winterof79 said:

06z Euro4 changed again southward

weather model euro4 h model - united kingdom - rain/snowfall [base + 1] - loop | weatheronline

WWW.WEATHERONLINE.CO.UK

---

Weather for UK, Ireland and the world. Sailing, Marine Weather, Weather maps, radar, satellite, climate, historic weather data, information about meteorology...

 

How accurate is this euro4 at 48 hours out  ?  Im guessing not very

 

showing continuous snow showers in my location for 6 hours plus at the moment...48 -54 hour mark...i can but dream......

 

[chris55]

2 minutes ago, Battleground Snow said:

Icon a little deeper and further north with Saturday system, a few people might at least see falling snow in the far south

 

Just grazes the south coast......

 

Its going to be a long few days lol

[Djdazzle]

You have to love the models.

A couple of weeks ago, we had that deep area of low pressure which, although cold enough, delivered relatively little snow.

Now, we have another low pressure system which, with the air not cold enough, looks set to deliver copious amounts of rain!

We need some great runs to lift the mood!

 

[Tim Bland]

8 minutes ago, goosey007 said:

How accurate is this euro4 at 48 hours out  ?  Im guessing not very

 

showing continuous snow showers in my location for 6 hours plus at the moment...48 -54 hour mark...i can but dream......

 

With uppers of -2 and flow from the west I’d says it’s very unlikely to see snow that far south. Perhaps high ground of Wales, Pennines and Moors but not low ground sub 200m