WinterOf47

The models are not high enough resolution to pick these events up. I was saying this the other day here that a little smudge of activity on one of the main models can be impactful locally. I noticed then a streamer over the South East was forecast for tonight but that seems to have moved to daylight hours tomorrow so I doubt will come to much other than a wet mix. I used to live downwind of Georgian Bay in Canada and they had mesoscale predictive radar out to 48 hours that was much better at picking up local activity…which regularly dumped 20cms on us, when the likes of the GFS had nothing.

Thanks! Guessed it was something like that. It is quite insane that despite the evolution in computing power, the ability to forecast with much precision beyond 5 days has only improved incrementally since the 1980s. I am pretty sure AI will fix this. The simple fact is that despite the humongous amount of variables, the weather today should be predictable from the surface and atmospheric data available 3 weeks ago. I know that with each day there is an exponential increase in the amount of calculations, but still, I think there should have been greater improvements than we have seen. However, would make these discussions a little more boring! The GFS is showing a potential streamer for Sunday night into Monday morning for the South east. Could give some in West Kent, South Essex, East Surrey, North Sussex and SE London their first snow of the winter, and the first taster of what will hopefully be a memorable spell. Unfortunately the resolution this far out is not great and I’m not sure how granular they get. In Canada we used to have predicted radar down to 3km and that was great at predicting LES, and a little smudge like we see below could drop 20cm in the space of 2 hours! Now only 4 nights away, so may be the GFS is picking up first signs of some potential activity. Just a subtle shift in wind could kill it off though, or enhance it. Close to the coast would be a mix, but inland on the downs especially, could be snow.

I know this is fantasy (by the way, I know this is related, but relatively new here…what does F1 mean?) at hr 354 of an OP, but it shows the kind of weather scenario that could develop if we ended up with persistent northern high. Even if it wobbles about between Greenland and Scandinavia, it will allow for lots of opportunities for snow as lows come from the south west or south east. A couple of weeks of northern blocking could make this one of the more memorable winters. Let’s hope it comes off.

That’s total accumulation and includes snow predicted to fall from now, including sunday onwards, which is definitely coming into some sort of sensible range.

I agree. If the grass is covered, the snow is powder, I will be quite happy.

Bit of perspective at this stage…most of us will be lucky to see more than 5 cms. However, this kind of chart is not always good at picking up localised accumulations from streamers. If the latest run pans out, I would expect to see a few lucky places on the East coast and south east get over 10-30 cms of snow locally.

This would be perfect timing for the coldest scenario, late Jan early Feb, bit like having a heat plume late July. Let’s hope it locks in and delivers.

If it helps, it’s not just us, North America is looking pretty snowless this Christmas too. GFS anomalies from the 12Z:

The GFS got last December’s snow right as well. It forecast 4-6 inches across the south East days before any other model picked it up. It is a bit all over the place ATM though so lots of scepticism this will be in later runs. However the set up they have at the moment is for snow in the North and inland from coasts exposed to the wind, but there is also a low pressure feature lurking out to the west next weekend that could prove interesting if the models align around cold northerlies. It was this kind of feature that evolved into last years event in the South East as it trundled along the South Coast then spun up to East Anglia. Anyway just a bit of fun from an OP run, but hopefully a sign of change.:

Any serious cold weather events predicted by the GFS more than 10 days out should be taken with a mountain of salt. The OP runs they were producing earlier this week for the run up to Christmas always seemed a tad far fetched. It seems that the Iberian/Azores high is a comfortable fit for the weather in the winter and the GFS is now accepting that. Even though the GFS is not be relied on more than 10 days out when predicting weather we might like to see, the kind of charts we are seeing now always do seem to be accurate! I would be extremely surprised if we see anything outside of the set up below at Christmas, and even into the New Year. This thing is not going to shift in a hurry. Personally, I am quite happy with that. Daytime highs touching the double digits and nights no lower than 5 degrees are pleasant. There should be quite a bit of sun as well. After the awful autumn of endless rain we had, this is very welcome (in the South at least - the North will get wet and cold incursions).

I lived in Barrie Canada for 7 years. I actually chose to live there because it was in the snow belt. We’d get lake effect snow when the wind came from a certain direction, and the rates of accumulation could be 5-10cms an hour and a squall could get stuck for hours over one location. I went to bed one night about 11.00pm and there was maybe 2 cms on the ground, and got up at 7:00am with 45cms…and the roads had been ploughed! (clearing the plough poop from the end of the drive in -20 was my least favourite chore). Incredibly 2 kms down the road they’d had nothing. The thing about that kind of accumulation though was that it would quickly compact to about 70% of that depth as the air gets trapped as it falls so quickly…like the air in duvet. One winter we had temps below zero from Jan 6th to March 20th, and about 2m of snow fell, but it only measured 75cms in my yard. It was very dense. It was still awesome though. Then I came back here

This has more comments, so I’m going to post here. This will be a tree killer storm (and any humans beneath). The ground is absolutely saturated down here on the south coast after a week of heavy rain showers and more to come, already got floods in some places. Most of the trees are still in full leaf…most in fact still green. There could be loss of life as the winds will be strong during the day on Thursday as well. I won’t be venturing out as at the least could be lots of road closures.

Everyone in the UK can blame me…I installed air conditioning in a couple of attic rooms at the beginning of July. Seriously, the models have been shocking beyond 5 days this summer, especially august…the only thing consistently predictable is their lack of predicting trends, let alone weather. Need to keep the memory of this close to hand when it comes to forecasts of blizzards in January!

The ensemble of the GFS 00Z run has temps around normal compared to a furnace for the OP. Is there an algorithm that determines which member is represented in the OP, or is it a sequential thing…they take in turns? I’ve never understood what determines when complete outliers are shown like this one.

If only. Would make up for the past 7 weeks if it came off. Heat all the way through till the beginning of September after this weekend.

Could it be related to the establishment of the jet stream further north for later into the year? To be honest, if this correlation is really strong…i.e. warm September mild winter, I am ready to throw September under the bus and write of this summer (except June) and hold out for something exceptional in terms of cold over the winter. Also I am away most of September

How have they performed so far this summer?

I really can’t quite get over how the forecast has collapsed so badly for this coming weekend. The models were reasonably consistent about there being at least some high pressure in the mix, and some were very bullish, up until yesterday, and now it is back to LP dominating, even in the SE which looked like it might be spared, but now is not. Losing any hope for August now really so starting to think of winter…does anyone who follows the analogues, know of years that match this year so far, especially with the sharp contrasts that have occurred during various seasons? How did the autumn and winter play out?

Agreed, the 00Z GFS has London touching 27 at noon on Thursday, so I would expect 30 to be the peak somewhere in the capital.

Indeed. The temp anomalies from 11th look very tasty. Possibly see 30 if this plays out but still a long way off…shame it’s 9 days out instead of 2. RPReplay_Final1690974816.mov

Agreed. This time last year we were starring down the throat of 2 days above 35. Yuck. The models this week are not too bad now for the south, with high lurking in some of the charts. 20-24 is ideal. Yesterday I was in Hove, clear blue skies and huge waves. Everyone was in summer wear as temp was about 21. Even with the wind, it was lovely.

Yep, the latest OP of the GFS is a true misery maker. A bit of temporary warmth and dry for the south early next week (when we are mostly back at work), then a descent into endless windy showery weather. Feel very lucky to have had my UK holiday in the last week in June, which wasn’t perfect, but much better than what is coming. The ensemble accumulated rainfall and temp anomalies for the next 2 weeks also show most off the UK, showery and cool. The South east will be bearable as it will be spared the worst of the rain and cool, but definitely not beach weather! RPReplay_Final1689407802.mp4 RPReplay_Final1689407756.mp4

Can anyone from Cornwall tell me what next weeks set up will likely bring from experience. Going to St Ives. Increasingly looking like westerlies with high to the south west and low to the northwest. Other than the odd front passing over, not much chance of heavy rain, but does this usually mean endless cloud for the far south west? Could handle sun and cloud, but being stuck under a blob of endless grey would be very depressing. (I live on the south coast which usually pretty pleasant with this set up).