Winter 2019/2020

[Rroff]

As there is no thread yet and things are just starting to look interesting on the model front I thought I'd start one.

Some speculation of a SSW type event mid-December (though the effect usually starts to be felt 2+ weeks later) with a good chance of significant arctic outbreak for some part of the northern hemisphere but too early to say what and where.

https://www.aer.com/science-research/climate-weather/arctic-oscillation/

The end of the GEFS run starting to show some promise for colder possibly snowy weather come December



https://www.theweatheroutlook.com/twodata/chart.aspx?chart=/charts/gefs/gefsens850London0.png?cb=2

Siberian snow coverage is progressing well and ahead of many recent years

https://www.natice.noaa.gov/pub/ims/ims_v3/ims_gif/ARCHIVE/EuAsia/2019/ims2019321_asiaeurope.gif

And we've seen early snow for some parts of the UK already with parts of Wales especially getting a taste https://www.bbc.co.uk/news/uk-wales-50376070

Gav's latest in-depth look at the potential for the coming winter:

 

[Rroff]

Not too bothered about snow ,im half way up a very steep hill ,cant do with the hassle (although did make it home when cormwall ground to a halt in January
as a bodyboarder and storm watcher im more excited about this weeks groundswell ,20 second period ,drooling
https://magicseaweed.com/news/xxl-swell-about-to-hit-europe/11625/

Certainly living in some interesting times for weather - though I'd like to see at least one decent winter in this era - the last proper snowy winter (lasting more in weeks timescale rather than the 2-3 days we've had of late and 5 foot drifts, etc.) in the part of the country I'm living now was a year before I was born.

 

[Rroff]

Not a fan of snow, its novelty quickly wears off. I would love it to be summer 12 months a year. Hotter the better.

I like a bit of novelty to break up the routine - not a fan of dealing with a prolonged wintery spell but a decent snowfall with 2-3 "snow" days I find as good as a holiday so to speak.

 

[Rroff]

Looking at approx. 3-5th Dec (and onwards) the models variations are going nuts unable to really handle the data (beyond the usual uncertainty with range) - typically in the past happening around a SSW type event. 1 and 10hPa charts show all kinds of disruption not that I know enough to read anything from it other than it is more unusual weather wise than normal.

 

[Rroff]

GloSea (MO seasonal forecasting system) is hinting at a slowdown of zonal windows as we enter December, which would mean not an end to the westerly and wet weather, but a reduction.

We have seen the start of a potential SSW event taking place, how this will affect the polar vortex for the UK its yet to be seen.

Ah that hated zonal word heh. Still everything to play for but at the very least the most positive looking (for wintery weather) signs heading towards winter we've had in a long time.

I just want the sunspots to come back. It's all very well being at the bottom of cycle 24 but it would be nice for cycle 25 to start.

Some claim SC25 has already begun or at least onset - technically there is some very slight activity which would be part of SC25 rather than 24 but IMO still 15-18 months away from a cleanly defined start of SC25.

 

[Rroff]

OP why do you make it sound like a good thing, being over dramatic elderly people die and there's many more road accidents as well as costing the economy!

Snow snow go away, come back another day

While I have sympathy for those in ill health who it will impact and can't avoid it - a large amount of those problems are because people aren't sensible and not prepared! and for that I don't have much sympathy. (And there is a happy medium between not being prepared at all and panicking and stocking up like its the end of the world but for some reason most people seem to fall to one of the extremes).

 

[Rroff]

WOW...

Not been in long so hadn't seen the GEM / ECM 12z output....stonker!!!

OK so it may be fantasy island stuff but it has legs and would bring the vortex down and with it cold and snow.

Yeah deeply FI stuff but better than the last couple of years which were just pure muck and meh at this point in the year.

 

[Rroff]

18Z updates are an improvement



Still everything to play for but good support for the potential for wintery weather - more so than the 12Z runs.

EDIT: 0Z the control and operational runs are all reaching at milder conditions while the ensembles are all over the place - which isn't so good on the face of it but IMO with a potential SSW event in play an indication that the models aren't able to nail down anything.



Way beyond the scope of my knowledge and needs combining with other data to tell any kind of story but that looks very potent for polar disruption and potential cold outbreaks

Other factors like the jet stream and NAO are marginal - not good, not terrible in terms of potential for wintery weather in the UK. Sun continues to be quiet without sunspot activity as far as that goes though some minor geomagnetic storming.

Data from www.theweatheroutlook.com

 

[Rroff]

Yeah I don't really remember winters like that - I think there have only been two in my lifetime in this country I've seen proper icicles forming from pipes and gutters, etc. I think the coldest I've ever seen in this country was -10C and that was only overnight once.

 

[Rroff]

Still no definite picture for the winter ahead emerging - but still everything to play for with good potential there. Couple of forecasts:

https://www.theweatheroutlook.com/t...=hpnews&id=5095&title=Winter+2019/20+forecast

https://www.gavsweathervids.com/winter-2019-20-weather-forecast.php

 

[Rroff]

Who's going to be putting on winter tyres though?

Got "all terrain", "all season" tyres on mine not sure about winters unless we have a solid forecast for prolonged cold.

 

[Rroff]

Sadly I don't think we'll see that - a brief blip around the 13th/14th that looks to be sleety at best for most of the country and still very uncertain whether any arctic/polar disturbance will pan out - it is looking like a glancing blow stratospheric warming wise which might throw some cold our way but nothing notable.

 

[Rroff]

I was planning on driving up to Scotland on Friday night to have a play in the snow on Saturday but the cold weather seems to have disappeared and any good climbing conditions have been stripped. Looks like it's just going to be a miserable mild, wet and windy weekend now instead so I've scrapped my plans.

Mid December looking interesting for snow over Scotland - when/if it does looks like it will be very heavy but conditions are marginal could be a lot of slush instead.

 

[Rroff]

Any chances of a northerly next week have gone, we will be stuck in a zonal pattern (Atlantic driven) with rain and average temperatures

We are too far from any kind of reliable timeframe to start talking about snow any further than 7 days out

Yeah sadly looks like the potential SSW is turning out to be just a glancing blow though still signs there might be more on that front to come. Lot of the potential for something wintery mid-month is biasing back towards zonal on the outputs tonight.

So, is it going to snow this year or what? I don't understand all these fancy charts, just give it to me straight.

Hard to tell really - the only thing that has been of note so far is that fairly early on wintery weather has been a possibility versus some years recently when the models had little to offer but zonal muck (rain, cool to mild temperatures and potentially windy).

 

[Rroff]

The PV on some runs has been obliterated, not what you would expect to see for the start of December.

Saying that, last year we always seemed to be at t+240 with an SSW on our doorstep only for it to never materialize.....I really don't want a repeat of last winter.

Not sure what to make of the latest models - seems any impact SSW wise is glancing and with quite a bit of support for central/eastern Europe seeing uncharacteristically mild weather towards mid/end of December but some hints it might play out longer term as splitting the PV. The only consolation I can take is that at least there isn't a shortage of options - I like some variation in the weather hate it when winter just turns into cool, rainy (zonal) muck for weeks on end.

 

[Rroff]

https://twitter.com/i/web/status/1204164632614768640

However Wednesday some should some the odd flurry - doesn't look like show stopping stuff even by Southern standards though :s probably wet mush at best.

https://twitter.com/i/web/status/1204119965919522816

Though other models like Arpege show it as contained mostly to high ground over North West Scotland.

 

[Rroff]

Ah this is so frustrating LOL no shortage of options for some wintery weather but it just doesn't seem to come off with lots of signals for continued cool, rainy weather and possible more flooding.

Some indications of potential for a very strong SSW event early in January but the polar vortex seems more resilient than usual at the moment shrugging off previous potential disruptions with ease.

 

[Rroff]

Its barely stopped raining for the last 2 weeks and its raining now. Roads are flooded right left and centre even the motorway was closed yesterday under a foot of water in places. 3 months of drought during summer and now its making up for it.



Bascially every xmas then. Well it should be dry next week for the first half of the week at least that'll do me.

Saw a nasty one on the way back from work early hours of this morning - the outside lane of the dual carriageway was flooded completely for about 30 yards (level with the verge) on the inside of a bend and in the dark completely invisible before you hit it - 2 cars had already had incidents before I got there looked like they'd rolled from the damage - fortunately police had put signs out before I got there.

 

[Rroff]

I'm no expert but it isn't looking to me like any of these potential SSWs are going to come off - the cold is just clinging on over the arctic every run it is just looking too strong to be displaced. Though the polar vortex can collapse very suddenly and often does from its strongest state I'm just not seeing it in the current setup - on the other hand it seems to be coming almost constantly under assault this year with indications of more to come so plenty of chances for it to still happen maybe later in January.

 

[Rroff]

Nothing in the models but mild and very mild with occasional cooler snaps - all the ingredients are there but the cold is firmly staying bottled up over the Arctic for now - even Norway, etc. isn't getting it like they normally would. Quite frustrating.