IW Met

Im certainly not one to ramp or anything, but I do find it rather interesting that the latest GFS somewhat resembles this in 1881. WWW.METEOCIEL.FR Archives NOAA NCEP de 1836 à maintenant By no means am I saying it will be anything like that! But it goes to show how patterns like this can evolve if everything is just right. Retrogressing high to greenland followed by a gently declining pressure up that way and a crazily south tracking jet.

The problem with a Scandinavian high is that in a sense it isn't always a true block. What I mean is that a Greenland high is quite often an extension or part of an Arctic high, and whilst a Scandi high can also work the same way (be part of an Arctic high like Feb 2018), more often than not a Scandi high is just a mid latitude block that is propped up by low pressure over Eastern Europe or the Med, and without the "prop" it often just sinks. So a Greenland high shifting to Scandi CAN happen, it just isn't a scenario that we usually see. We do occasionally see a Westward extension of the annual Siberian high but this is usually its own unique pattern and unrelated to Northern blocking. So to answer the question, yes it is possible but unlikely. Original post: https://community.netweather.tv/topic/99584-model-output-discussion-into-winter/?do=findComment&comment=4971569

The problem with a Scandinavian high is that in a sense it isn't always a true block. What I mean is that a Greenland high is quite often an extension or part of an Arctic high, and whilst a Scandi high can also work the same way (be part of an Arctic high like Feb 2018), more often than not a Scandi high is just a mid latitude block that is propped up by low pressure over Eastern Europe or the Med, and without the "prop" it often just sinks. So a Greenland high shifting to Scandi CAN happen, it just isn't a scenario that we usually see. We do occasionally see a Westward extension of the annual Siberian high but this is usually its own unique pattern and unrelated to Northern blocking. So to answer the question, yes it is possible but unlikely.

Down here we need that surface wind to be north of east, even if just by 10 degrees, otherwise the channel will keep surface temps a fair bit higher than just 10 miles north and west. Luckily the fetch is short which means any surface warmth from the channel will be shallow, so central and northwestern parts of the island are often much colder than eastern and southern parts in any potential east flow.

Sea temps are surprisingly not as high as many might think. Compare the buoy temps from Nov so far this year with previous years. We are sat at maybe 1°C or (less) above the average from the last 15 years.....down here anyway (English Channel). National Coastal Monitoring - Realtime Data COASTALMONITORING.ORG

Having an extremely cold spell across many parts of the US and even Siberia at the moment. There are some positive anomalies too of course, but that cold over the US looks fairly extreme!

There were some fairly decent easterlies in the 90s, for example Feb 4th - 12th 1991 with a Scandi high and huge snowfalls in some parts. Nov 19th - 22nd 1993 that brought quite widespread snow. Feb 12th - 15th 1994 with a scandi high and lots of snow in south and east. Dec 4th - 16th 1995, Jan 21st - Feb 8th 1996, Dec 21st - Jan 10th 96/97 that brought snow to the usual areas and freezing drizzle to the IOW. Dec 14th - 17th 1997, although it was fairly short lived but still brought plenty of snow showers followed by a very heavy transitional snow event to many places in the UK. I would say no less than any other decade to be fair. I would love to see day by day strat charts for the dates above as I am sure there are probably splits and displacements driving some of them, as we know very well that even just minor warmings can occasionally influence the strat, especially if wave 2, although during the Neutral ENSO years I am leaning more towards trop driven blocking or at least lack of strat-trop connection for the early season Easterlies.

A bit off topic, but here on the IOW we had 2 amazing falls of snow in January and March 2013, 3 falls in 2018 and about 5-8cm worth in 2019 away from the east and south coast of the island. All cold was strat triggered too, with 2019 being a displacement. No different to the previous 40 years here really. Our worst snow drought was from Dec 1987-Nov 1993, with 1991 having a slight dusting. We are yet to beat that!

I agree, at least for the southern half. The norhtern half of the UK would take a beating!

Synoptically looks reasonable but the cold is much further north, so really based on this run, only half the country will be seeing the good stuff while the other half watches on TV

Im very relaxed, im just talking about what this run is showing, not what I think it will be showing when the day comes. Thats the whole point of this thread, to discuss what is currently being shown

I do think so, those uppers are pretty poor for southern parts.

I think the comment meant South-southwest when saying SSW

6z Arome The problem we have is that the air will be fairly dry, particularly on the western edge of any streamer type activity that runs south through the country, so we will be seeing a lot of the precipitation evaporating before it reaches the ground, but that said, where it manages to become a little heavier it will almost certainly be snow. Down in the far south (along the coast) it will be too far away from the source of the convective streamers, this means that most of the rain, sleet or snow will have fallen, leaving a lot of the far south mostly dry, at least through the daytime anyway.

No problem if the main low stalls, as long as it sends a trough eastwards, that can then "prop" up any heights to our north.

Doesn't look terrible to be honest, hints of an undercut with the main low out west stalling.

I wish people would stop saying things like this . 2018 and 2019 saw significant snow in lowland UK including right along the south coast of the UK. I have said this many times and I will say it again. It hasn't been cold because it has been displaced over the other side of the northern hemisphere. Its pure synoptics that have meant the cold isn't in Europe, that's it, plain and simple. A change in the synoptics over the coming week or two may well introduce much colder conditions into Europe, then....if that Strat warming has enough influence, we may then see that cold advected westwards......maybe.....

....and there it is although to be fair anything past 96 hours is so uncertain at the moment. Its nice to have a fantasy though

Yes that frame but the trend on GFS and ECM is to drop heights a little further north and the short-med term trend isnt as good as it was. That said if it fdrops that bit more south then a good portion of UK could get a proper blast, but the southern half likely missing out.

Thats going to go bad if cold is whats wanted , soon to see shortwaves rippling east in atlantic. If it can head a touch further south though then we may be in with a shot.

Sorry, somehow I ended up replying to the wrong post! oops! haha, I didn't sleep well last night! ha Thats a now out of date run and you are using a random perturbation. If you make forecasts using this method im afraid you will end up on the worst side of wrong many times before the winter is out Best use the operational run and then see how many ensembles and/or other models back it up

I find comments like this extremely frustrating. People seem to forget so quickly! The only reason the cold is not over our side of the northern hemisphere is because of synoptics, plain and simple. The cold is there, its just the wrong side of the pole. Jan 2019 was pretty weak but still plenty of cold in the northern hemisphere and N Europe! Feb 2018 perhaps? Lack of cold in recent years!

Yes but it all depends on the synoptic setup. If the cold is too far east, it will most likely stay there. The ideal scenario is for a low to plunge deep into russia and sink south/southeast followed by high pressure settling to the north of it (east/northeast of UK). This is when we get the super deep cold. You can on occasion get a retrogressing high but these tend to be on the same latitude as the UK, so yes they can bring cold but that tends to be later in Jan or Feb when the continent/russia/siberia is at its coldest.

Not in the near future! The northern hemisphere has the cold, its just over the opposite side. The recent synoptic setup has meant the cold has been pushed away from the pole and into eastern Siberia and Asia along with Alaska. Its not that the cold isn't there, its just in the wrong place.

Oddly enough China Crisis, Wishful thinking. Its because of the video though. It looks cold and late autumn/early winter in the music video and it gives me that "feeling" :)