Winter 20/21 - General Discussion

leahyl · 11-09-2020 11:54am

10 year anniversary this year.....could it happen again??! Hey, it's 2020!

sryanbruen · 20-09-2020 12:35pm

This likely won't be much an issue here as compared to Netweather but I thought I should mention it anyway.

A weak stratospheric polar vortex in late autumn is a good starting point but rarely does it coincide with a season of consistently weak SPV, 2009-10 being such a year. Recent years have had the tendency to feature a weak SPV through the autumn period or a disconnection between the trop and strat before a big ramp up or reconnection by December or January. This was especially the case in 2016-17. The life span of the SPV is non-linear, every season has maximum and minimum spikes to various degrees.

I used models like the CFSv2 in years such as 2018-19 (my most recent winter forecast) in helping to anticipate major sudden stratospheric warming (SSW) events at long ranges. The issue with this is the model has a negative bias with hindcasting zonal mean zonal winds at 60N 10hPa that might not necessarily reflect the actual forecast. Simon Lee has a great thread on this matter below.

https://twitter.com/SimonLeeWx/status/1306929368288178176?s=20

I felt confident on using this model to anticipate a major SSW of some kind during December 2018 or January 2019 due to a theory regarding increased risk of such when the QBO is transitioning from easterly to westerly. Fortunately, this indeed verified but the effects were very different from the major SSW event in February 2018 of course. The hindcast of the CFSv2 is again showing weak zonal mean zonal winds for the autumn into the winter period but not to be relied upon and I don't have any other factors like the QBO in 2018-19 to make me consider otherwise this time.

To answer a question set forth by hatrickpatrick, I think the earliest the annual stratosphere watch thread should be created is late October. You or anybody else are obviously more than welcome to do so any time but that's just my opinion.

Meanwhile, on the ENSO side of things, we are firmly into weak La Nina now and it's looking more like an East Pacific (EP) Nina at the moment. Models like Glosea5 and CanSIPS show the possibility of this La Nina strengthening to strong levels by the end of the year. As mentioned prior, strong ENSO events historically do not correlate well for high latitude blocking dominated winters in our part of the world though the analog record of such is small. I think the chances of a strong La Nina are low at the moment with moderate having the highest probability. La Nina events favour the earlier part of the winter to having an increased chance of -NAO whilst the latter part favours +NAO so La Nina winters tend to be more front-loaded although, especially with weak events, this link is weak with decent number of exceptions from the past.

Anyway, I digress.

Oneiric 3 · 21-09-2020 9:28pm

Fairly typical 'La Nina' pattern over the N. American continent:

which would suggest that explosive lows would easier develop of the eastern seaboard, but which really means nothing for us as 1. this could amplify high pressure zone over the central or NE Atlantic or, just keep the pattern flat and stormy over us, with the latter pattern slightly more likely if the La Nina remains in weak state.

sryanbruen · 25-09-2020 6:02pm

Could not resist sharing this super interesting thread.

https://twitter.com/griteater/status/1309524586803998721?s=20

https://twitter.com/griteater/status/1309524598480949250?s=20

https://twitter.com/griteater/status/1309524601832198148?s=20

sryanbruen · 25-09-2020 6:18pm

And to simplify what the above showed, most of the negative Arctic Oscillation / North Atlantic Oscillation combo (which indicates blocking in the high latitudes and cold air displaced into the mid latitudes like Ireland) winters have been associated with cool ENSO or La Nina events since 1990 as compared to El Nino.

The pattern of the Octobers preceding these La Nina winters bears a striking resemblance to the projected synoptic profile across the Northern Hemisphere in late September / early October 2020 with including, but not limited to, blocking high pressure over the Urals and a corresponding trough near or over Ireland.

The last tweet shows the 500mb height anomaly for the following November/December which both feature Greenland blocking and a southerly tracking jet stream. This is an overall average for the analog years and of course, extreme years like 2010 will skew things somewhat but interesting nonetheless and each of the years featured high latitude blocking at some point through their respective months.

All food for thought and for fun, nothing more, nothing less.

lapua20grain · 01-10-2020 2:42pm

https://twitter.com/judah47/status/1311658936597131265?s=19

SeaBreezes · 01-10-2020 9:55pm

lapua20grain wrote: »

https://twitter.com/judah47/status/1311658936597131265?s=19

Warm east might mean cold for us?

Graces7 · 02-10-2020 9:46am

Memories keep coming of my Orkney decade. Snow was part of every winter at some stage. But we were well equipped, not like the disruption in less experienced places. My home help would arrive with the shopping on the family tractor in two feet of snow.

The island lorry ( rubbish collection etc) had a snowplough attachment. One year ( and I could see the lane from my door, but, thankfully, not hear the language..) it got stuck in the snow and had to be pulled out by a tractor....

Watching my hens emerge into the snow, and be horrified to LOSE THEIR FEET! They have such expressive faces.

" Ah yes, I remember it well.!"

Graces7 · 02-10-2020 10:16pm

There was one week when the power failed on the whole island; there was thick snow on the ground..

Romantic soul that I am, I stood at my front door in the moonlight, gazing at the silent expanses of white, dreaming of the "old days" when no one had electricity and life was a balancing act.... Then my practicai streak reminded me that there was a freezer and cupboards full of food behind me and that thankfully we will never know that kind of dire poverty again.

But it was so utterly lovely, that snow silence. Whiteness in the moonlight.

Snow seems to do that; take us back to "times long past"; maybe as it is blessedly rare we romanticise it? It is an adventure! And the utter silence it instils, So you hold your breath.,

In those Orkney years I saw the reality of annual snow. The last snowman I made was there; I made it too near the back window and it used to make me jump as I thought someone was out there!

If we get snow , I will put a large snowman on guard on the drive!

Well, we can dream ..How about a thread on snow dreams! Later I mean..We have the autumn gales to get through first...

mcburns07 · 02-10-2020 10:19pm

I wasn't aware that snow was a common thing in Orkney, I know it's quite far north but it's surprising considering it's in a small island.

nacho libre · 02-10-2020 10:22pm

SeaBreezes wrote: »

Warm east might mean cold for us?

When places like Alberta get milder weather during winter than they are used to, it can be good news for us.

Graces7 · 02-10-2020 11:13pm

mcburns07 wrote: »

I wasn't aware that snow was a common thing in Orkney, I know it's quite far north but it's surprising considering it's in a small island.

It is between the far north of Scotland and Shetland so of course it gets snow. Not sure why it would not? Regardless of size. It snows at sea too

.. And not just one island but a whole collection of islands. I was on one of the Outer North Islands. One larger and many smaller. Ours was about six miles by two. At least 2 hours from mainland Orkney by boat...

We had snow every winter. There is a website listing the Top Ten snowiest places in the UK. and Orkney comes 4th with snow on 59 days of the year. Lovely photos if you google "snow Orkney". The gales were amazing so imagine the drifts....:eek:

Oneiric 3 · 03-10-2020 12:48pm

https://twitter.com/JoaquimCampa/status/1311391615425093634

Cluedo Monopoly · 09-10-2020 6:28pm

I had hailstones today in Connemara. Nasty shower. Nice to see some white stuff.

bazlers · 12-10-2020 10:59am

Has anyone put out any entertaining winter forecast yet?

Gonzo · 12-10-2020 12:10pm

bazlers wrote: »

Has anyone put out any entertaining winter forecast yet?

it's a bit early really as we are only half way through Autumn. Alot can happen between now and December. Gavs weather will issue his winter forecast around December 2nd.

SeaBreezes · 12-10-2020 10:56pm

https://twitter.com/severeweatherEU/status/1315653538379423746?s=20

bazlers · 13-10-2020 12:13pm

Im sure MT Craniums' Winter forecast will be along quiet soon.
My prediction is for a colder than average winter.
Second half of November might bring first snowfalls.
December will be average enough but after xamas another lengthy spell of frigid air will encroach from the north east and decend upon us for the first two to 3 weeks of january. This will be bitter cold with some of the coldest temps recorded for january for up to 40 Years.
It will be dry though with only maybe one big snowfall.
February will be average with March also cold but not near as cold as January.
Time will tell.

NickNickleby · 13-10-2020 12:37pm

Well, bazlers, that's a real pick-me-up

:)

however, can I ask you to move November's snowfall to the 2nd and 3rd week of December, just to make it more Chrismassy, like.

Failing that, we may have to burn down the observatory :pac::pac::pac:.

bazlers · 13-10-2020 12:50pm

NickNickleby wrote: »

Well, bazlers, that's a real pick-me-up :)

however, can I ask you to move November's snowfall to the 2nd and 3rd week of December, just to make it more Chrismassy, like.

Failing that, we may have to burn down the observatory :pac::pac::pac:.

Yes burning down the observatory always helps ; )

Gonzo · 13-10-2020 3:14pm

This winter is likely to be colder than the past two winters which is an easy target to beat. It remains to be seen if we get anything special this winter but I've a feeling we will definitely see more in the way of frost and precipitation of a wintry nature this winter compared to recent winters with perhaps the first half of winter being the coldest half.

One of my main wishes for this winter apart from cold and snow is an overall dryer winter than last winter, completely fed up of the Atlantic and it's deluges, the past 12 months has overall been very wet aside from Spring.

Graces7 · 13-10-2020 11:44pm

Gonzo wrote: »

This winter is likely to be colder than the past two winters which is an easy target to beat. It remains to be seen if we get anything special this winter but I've a feeling we will definitely see more in the way of frost and precipitation of a wintry nature this winter compared to recent winters with perhaps the first half of winter being the coldest half.

One of my main wishes for this winter apart from cold and snow is an overall dryer winter than last winter, completely fed up of the Atlantic and it's deluges, the past 12 months has overall been very wet aside from Spring.

Thank you. My immediate response to this, being of a practical nature, is to make sure I lag the pipe from the gas tank outside, and to store some water..

M.T. Cranium · 14-10-2020 6:56am

We had our first snow at my location earlier today, about 3-5 cm of wet slushy accumulation, trending towards 15 cm on higher slopes around here (my elevation is 1080 m). This is actually two weeks later than 2019 but still a bit earlier than long-term average for this location.

I am as alleged working on a winter outlook, not very far into the process yet and hoping to have something ready by the weekend perhaps, 20th absolute deadline.

No preliminary hunches or impressions. I do know people who are gung-ho about this winter in Britain, but I think quiet sun is the main foundation of their optimism and we've had that for several years now.

Like the patient gambler at the blackjack table, the chances of hitting a winning streak are always better the longer you play, so there is that. Even if this is the modern equivalent of the 1920s you could hit a 1929.

Looks like some transient cold in central to eastern N America in coming week, but that's not a good omen statistically at least, the years I came up with as analogues all sucked for European cold winters (Oct 1972, 74, 87, 88, 2006 were among the colder ones). Could be a case of firing up the jet at an inopportune time and tilting the odds towards zonal flow.

I suspect the indicators and trends will be weak favouring a near-average outcome but will go through the whole process and see what the number crunch indicates.

antimatterx · 14-10-2020 10:16am

Gonzo wrote: »

This winter is likely to be colder than the past two winters which is an easy target to beat. It remains to be seen if we get anything special this winter but I've a feeling we will definitely see more in the way of frost and precipitation of a wintry nature this winter compared to recent winters with perhaps the first half of winter being the coldest half.

One of my main wishes for this winter apart from cold and snow is an overall dryer winter than last winter, completely fed up of the Atlantic and it's deluges, the past 12 months has overall been very wet aside from Spring.

I would bad weather and would love nothing more than a bad Winter, but it would have to my a dry winter for me to enjoy.

Loughc · 14-10-2020 10:55am

bazlers wrote: »

Im sure MT Craniums' Winter forecast will be along quiet soon.
My prediction is for a colder than average winter.
Second half of November might bring first snowfalls.
December will be average enough but after xamas another lengthy spell of frigid air will encroach from the north east and decend upon us for the first two to 3 weeks of january. This will be bitter cold with some of the coldest temps recorded for january for up to 40 Years.
It will be dry though with only maybe one big snowfall.
February will be average with March also cold but not near as cold as January.
Time will tell.

I'm predicting a mild, wet, windy winter.

Gonzo · 14-10-2020 12:30pm

Loughc wrote: »

I'm predicting a mild, wet, windy winter.

more than likely that is what we will get as it is the form horse for Irish winters, given the almost unbroken run of mild winters (if you ignore that the Beast From The East in 2018 was more of a Spring event), we seem to get 1 decent winter every 10 years or so, last one being 2010, so mild winters tend to have a 90% success rate in this country.

We are overdue a cold winter at this stage, particularly a cold December or January.

Artane2002 · 14-10-2020 4:14pm

Gonzo wrote: »

more than likely that is what we will get as it is the form horse for Irish winters, given the almost unbroken run of mild winters (if you ignore that the Beast From The East in 2018 was more of a Spring event), we seem to get 1 decent winter every 10 years or so, last one being 2010, so mild winters tend to have a 90% success rate in this country.

We are overdue a cold winter at this stage, particularly a cold December or January.

2017/18 was pretty decent by Irish standards in my opinion, even ignoring the BFTE. it had many snowfalls, like the one on December 10th 2017 for example. Storm Fionn in January 2018 brought snow showers with lying snow even in Dublin, which is unusual for a northwesterly. February 2018 had some snow showers too from northwesterlies and also a frontal snow event which gave slight accumulations in the midlands and east around the 6th if I remember correctly.

2014/15 wasn't too bad, it had lots of very frosty mornings and a temperature of -8c in Dublin (Casement?) in February 2015.

nacho libre · 15-10-2020 2:25pm

Any sign of a Canadian warming this November:D

It has been a while since we had a proper snow event during the winter months

I'm getting the impression from M.T. Cranium's earlier post that he thinks this winter will be an average one with no notable cold period. If this is the case we could still get a few snow days at times, which would be a lot better than last year.

Artane2002 · 15-10-2020 6:35pm

nacho libre wrote: »

Any sign of a Canadian warming this November:D

It has been a while since we had a proper snow event during the winter months

I'm getting the impression from M.T. Cranium's earlier post that he thinks this winter will be an average one with no notable cold period. If this is the case we could still get a few snow days at times, which would be a lot better than last year.

March could bail us out as usual if the winter fails :rolleyes:

bazlers · 15-10-2020 8:09pm

Even MT wont get it close to100% right but I will say he is the best i know of for long range anyhow.
I still say we will get decent cold this winter at times.

ZX7R · 17-10-2020 11:47am

I'm cheating a bit but I expect to see snow by mid November even earlier as I live in eastern Poland now.
Temperatures are starting to drop after an extremely mild autumn so far .
A slight rise towards the end of next week into the mid teens and expected to drop off there after.

Rebelbrowser · 17-10-2020 1:22pm

There's always a view here that we don't want snow over the Christmas period as it would interfere with visiting, socialising, etc. Arguably, therefore, if there was ever a year to get a snowy period over the last week of the year it would be this...... Kids would all be at home to enjoy playing outside with their friends too.

Gonzo · 17-10-2020 3:05pm

yep normally I wish for snow through most of the winter with the exception of the 2 weeks leading up to Christmas day but this year is completely different as Christmas is basically a write-off this year so let it snow instead! At least we would have that to enjoy.

Humberto Salazar · 18-10-2020 10:24am

MT warning his winter forecast may not be what we want to hear tomorrow. I do want to see a very mild November and early December, then by law of averages the pattern must change by mid to end December to much colder weather. And we're due a colder than average winter. Purely speculating here, no science involved.

Jimbob1977 · 18-10-2020 10:29am

Does anyone happen to know if October snowfall is possible?

In my lifetime, I can only remember snow in November to April.

I seem to recall May 1st snowfall in the late 1980s.

esposito · 18-10-2020 10:41am

Humberto Salazar wrote: »

MT warning his winter forecast may not be what we want to hear tomorrow. I do want to see a very mild November and early December, then by law of averages the pattern must change by mid to end December to much colder weather. And we're due a colder than average winter. Purely speculating here, no science involved.

Fully expecting him to mention “big windstorm around Christmas or just after” because of full moon etc. Forecast out tomorrow I believe.

esposito · 18-10-2020 10:44am

Jimbob1977 wrote: »

Does anyone happen to know if October snowfall is possible?

In my lifetime, I can only remember snow in November to April.

I seem to recall May 1st snowfall in the late 1980s.

It happened in October 2008. Around 29th -31st in the east (mainly falling on high ground) was a light dusting on the Dublin mountains if I do recall.

Gonzo · 18-10-2020 11:36am

we had a covering of snow here in Meath end of October 2008,however I wasn't here to enjoy it, was in Berlin at the time and it was snow free there, once I got back home the snow was well and truly melted.

Beechwoodspark · 18-10-2020 11:57am

esposito wrote: »

Fully expecting him to mention “big windstorm around Christmas or just after” because of full moon etc. Forecast out tomorrow I believe.

V much an amateur when it comes to all things forecasting. But is there a strong connection between full moons and wind storms?

ZX7R · 18-10-2020 11:57am

Jimbob1977 wrote: »

Does anyone happen to know if October snowfall is possible?

In my lifetime, I can only remember snow in November to April.

I seem to recall May 1st snowfall in the late 1980s.

I remember snow falling in October at least 4 times during my childhood living in Wicklow.

Gonzo · 18-10-2020 11:58am

Humberto Salazar wrote: »

MT warning his winter forecast may not be what we want to hear tomorrow. I do want to see a very mild November and early December, then by law of averages the pattern must change by mid to end December to much colder weather. And we're due a colder than average winter. Purely speculating here, no science involved.

He mentions the word mild is going to get a decent workout this winter, it couldn't be even milder than last winter unless were talking about 12-15C days throughout the winter 3 month period and a record breaking Polar Vortex that beats last year's record breaking PV.

mcburns07 · 18-10-2020 1:14pm

Luckily MT is as accurate as every long range forecast

Still, looking forward to hearing his thoughts.

nacho libre · 18-10-2020 2:14pm

Humberto Salazar wrote: »

MT warning his winter forecast may not be what we want to hear tomorrow. I do want to see a very mild November and early December, then by law of averages the pattern must change by mid to end December to much colder weather. And we're due a colder than average winter. Purely speculating here, no science involved.

This is the impression i got from his post last week. As we see the polar vortex is now firing up, which could last months before we get a pattern change.
However if systems start to run on a nw- se axis we could eek some snow days out of it in some parts of the country, but it will be short-lived before the Atlantic takes over again.

Gonzo · 18-10-2020 3:16pm

the Atlantic is set to be unleashed and the PV is going to really power up over the next few weeks, however that is perfectly normal behavior for November. It's rare that we get a dry and cold November. November is typically one of the wettest months of the year as the PV usually kicks itself into gear by November. November 2018 and November 2019 were both incredibly wet here in Meath.

nacho libre · 18-10-2020 5:09pm

Gonzo wrote: »

the Atlantic is set to be unleashed and the PV is going to really power up over the next few weeks, however that is perfectly normal behavior for November. It's rare that we get a dry and cold November. November is typically one of the wettest months of the year as the PV usually kicks itself into gear by November. November 2018 and November 2019 were both incredibly wet here in Meath.

Yes it is, but once the Polar Vortex powers up it can last for months depending on how strong it is. We just have to hope it can be split or disrupted at some stage. It will be disappointing , with all the low solar activity in recent years, if we don't get something favourable this winter.

snowstorm445 · 18-10-2020 5:13pm

I remember a work colleague of mine last year talking about how even in her native Estonia they had no snow that Christmas, and temperatures were about 15 degrees above average, seems to be the same depressing story elsewhere in Europe. The thing is that it would have be considered weird a decade ago, but at least in this part of the world its fully expected at this stage. Every consecutive winter seems to be guaranteed to be worse than the one that went before. As much as I dislike the term as it’s been used this year, this seems to be the new normal (and as with every year, I’d very much like to be proven wrong).

M.T. Cranium · 18-10-2020 9:30pm

Well you might not find this too discouraging ... the winter outlook that I will be including in the morning forecast ...

Winter forecast ... The first half of the winter including December and most of January looks rather mild and occasionally stormy with temperatures 1 to 3 deg above normal and rainfall near average, little snow expected away from perhaps higher ground in the north. The second half of the winter looks more promising. The analogue set shows a tendency to blocking in February and some of the years in the set are quite cold. So the forecast conservatively says dry and rather cold weather patterns may dominate February and early March, with some chance of a more severe cold developing, and one or two snowfall events possible. A few of the analogues see the transition earlier allowing the colder synoptics to appear in January. I would say on balance this is a promising winter but with perhaps a one in three chance of remaining too mild throughout for winter weather enthusiasts.

giveitholly · 18-10-2020 9:56pm

M.T. Cranium wrote: »

Well you might not find this too discouraging ... the winter outlook that I will be including in the morning forecast ...

Winter forecast ... The first half of the winter including December and most of January looks rather mild and occasionally stormy with temperatures 1 to 3 deg above normal and rainfall near average, little snow expected away from perhaps higher ground in the north. The second half of the winter looks more promising. The analogue set shows a tendency to blocking in February and some of the years in the set are quite cold. So the forecast conservatively says dry and rather cold weather patterns may dominate February and early March, with some chance of a more severe cold developing, and one or two snowfall events possible. A few of the analogues see the transition earlier allowing the colder synoptics to appear in January. I would say on balance this is a promising winter but with perhaps a one in three chance of remaining too mild throughout for winter weather enthusiasts.

The cold usually gets pushed out to March/April,seems to be the trend more often than not the last 10 years

Gonzo · 18-10-2020 11:02pm

M.T. Cranium wrote: »

Well you might not find this too discouraging ... the winter outlook that I will be including in the morning forecast ...

Winter forecast ... The first half of the winter including December and most of January looks rather mild and occasionally stormy with temperatures 1 to 3 deg above normal and rainfall near average, little snow expected away from perhaps higher ground in the north. The second half of the winter looks more promising. The analogue set shows a tendency to blocking in February and some of the years in the set are quite cold. So the forecast conservatively says dry and rather cold weather patterns may dominate February and early March, with some chance of a more severe cold developing, and one or two snowfall events possible. A few of the analogues see the transition earlier allowing the colder synoptics to appear in January. I would say on balance this is a promising winter but with perhaps a one in three chance of remaining too mild throughout for winter weather enthusiasts.

that almost sounds like a repeat of last winter, not good news at all!

Cluedo Monopoly · 18-10-2020 11:12pm

M.T. Cranium wrote: »

Well you might not find this too discouraging ... the winter outlook that I will be including in the morning forecast ...

Winter forecast ... The first half of the winter including December and most of January looks rather mild and occasionally stormy with temperatures 1 to 3 deg above normal and rainfall near average, little snow expected away from perhaps higher ground in the north. The second half of the winter looks more promising. The analogue set shows a tendency to blocking in February and some of the years in the set are quite cold. So the forecast conservatively says dry and rather cold weather patterns may dominate February and early March, with some chance of a more severe cold developing, and one or two snowfall events possible. A few of the analogues see the transition earlier allowing the colder synoptics to appear in January. I would say on balance this is a promising winter but with perhaps a one in three chance of remaining too mild throughout for winter weather enthusiasts.

I'll take it. I much rather cold weather at or after Christmas. There's not a lot else happening in January/February.

Winter 20/21 - General Discussion

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