BlueHedgehog074

Your short range model posts make for a great read. Kinda wish that Low in the Atlantic on the charts could be further West early next week, as will be going to Wales and would love it to stay dry and settled. But I suppose it could be worse.

It might be the day after Halloween, but that 12Z GEFS ensemble member 2 is a spooktacular run for the cold and snow fans!

Yeah, it’s probably better to have something like that happen later, especially when the setups that a beaten up Vortex could lead to, is more likely to deliver more in the way of sleet and snow at that time of year. Providing the Low and High Pressure systems don’t end up in the wrong places for cold and wintry weather over the U.K. (As @MP-R says, having any blocking in the correct places). The models, such as 00 GFS, show that High Pressure will be taking its morning stretch in the Atlantic today: And the same tomorrow: A chilly next few days in the Northerly to Northerly Easterly winds with a mix of showers in places - rain, hail, graupel, with sleet and snow over high ground. ?

It’s deep into the dreamland, but one interesting aspect looking at the 18Z GEFS postage stamps - the lack of a flat zonal Westerly flow over the U.K. There might be the odd one or two, but most seem to show quite a meridonal pattern. The idea of continuing to see some slow moving and wavy/blocked setups is a real possibility.

Looks like a couple more generally bright and settled days to come, mostly over Southern areas, with models showing High Pressure being invasive over the South-Western areas of the UK. Knocker and some of the others go in great detail regarding the weather for next few days, so will keep it brief. Today does indeed seem to be the warmest day (feels very mild right now), according to the GFS UK Maximum Temperature charts: The warm temperatures reserved for South and Eastern areas of the U.K. Best to make what you can of today and possibly tomorrow, as the very mild temperatures for South and Eastern parts are going to get snatched away. You can see on those 06Z GFS 500mb and Sea Level Pressure charts, lower pressure and lower heights will dig down from the North. This squeezes the Western/South-Western UK High Pressure out further West with it amplifying in the Atlantic. A chillier flow floods down from the Arctic on Friday with sunshine and showers for places. Wintry I suspect over the Northern hills. All the models in brill agreement for this Northerly now and does look certain. This is what the various operational models show for Saturday. 06Z GFS: 00Z ECMWF: 00Z GEM: 06Z ICON: 00Z NAVGEM: All show a cold plunge from the North with the Atlantic High Pressure ridge poking into Eastern Greenland. They do all show very minor differences from one another as you would expect at that sort of time-frame. The Atlantic ridge, for example, seems the most amplified on both 00Z NAVGEM and 00Z ECMWF runs. For some reason, the 00Z UKMO completely disagrees and thinks everywhere could be covered in snow... The UKMO must have had too many drinks at the pub with the 18Z GFS last night and didn’t get a good night’s sleep. Most likeky just a glitch as to how it came out at 72 hours on Wetterzentrale for that particular run. Main thing, however, is support for an Arctic blast looks rock-solid for this weekend with a transformation in the weather; cold nights, frosty mornings, a chilly, blustery, Northerly wind and a chance for some wintry weather in places. Mostly of sleet and snow over high ground, but some heavier showers could drag the sleet and snow line to down lower levels at times. Low level sleet and snow probably most likely just for Northern areas of the UK, which would see the coldest conditions. Away from the showers, it could be bright and sunny at times, particularly over in-land areas of the U.K away from Eastern and Western coastel areas (this Friday, though, would probably see rain and hail showers streaming through the Midlands from the Cheshire Gap via a North-Westerly flow). Be quite a change from what we’ve been used to.

If the likes of the ECMWF keep showing that sort of outlook with Low Pressure becoming more concentrated to the South/South-West of the U.K with the flow becoming more South-Easterly, then it will be something worth taking more notice of. Particularly if other models start supporting it. While the 00Z GEM isn’t exactly the same towards the end (the blocking High is generally positioned more further North-East towards Eastern Scandinavia/Russia, it does still have the flow generally becoming more South-Easterly for the U.K.. Probably not as warm as the ECMWF. But having the flow becoming more towards the South-East or South could be a feasible evolution to head towards. Personally, if the likes of the ECMWF does start to occur more frequently, then would personally love for that Eastern UK blocking High Pressure to be a little further West or South-West, so that it ends up becoming more settled with any Low Pressure to the South-West being pushed out the way. Admittedly though, an looking forward to the Northerly before worrying too much about what may happen after. The mid-Atlantic ridge toppling into Scandinavia does look a likely solution, though.

It does look like on those NOAA anomaly charts a Scandinavian ridge developing, marked out by those positive anomalies and the big bend in the upper flow in that area. A great post I have to say. Provided a lot of chuckles! May just be one of the funniest I’ve stumbled across in the thread this year.

It’s almost like something out of a horror movie! But one with a happy ending where the good guy - the High Pressure and its ridges - defeats the bad guy - The Vortex!

Yo! A link to his LRF right here (page 3 of this thread):

Skullzrulerz covered it on the previous page, but certainly a high quality High Pressure system showing on the 12Z ICON over Scandinavia. Towards the beginning of next week. Some remarkable upper 850 hPa cold over the Scandinavian region. A more favourable orientation to the Scandavian High with a longer drawn flow from the North-East and that cold could pounce like a panther towards the U.K. (Though would have to bear in mind some of that upper cold would probably get mixed out fairly quickly as it approached the U.K).

A little area of -10*C 850 hPa temperatures scraping past the Western edge of Scotland on the GFS 00Z run for early Saturday at 123/126 hours. That wouldn’t be too out of place in November (even if those -10*C 850 hPa’s get mixed out quickly). No real signs of any watering down of the Northerly later this week on the GFS. And with some kinks in the flow, I suspect there could be some more organised areas of showers or longer spells of precipitation at times, some of which would be wintry over the hills. But perhaps the air mass being cold enough at times for something wintry to some lower levels too. More especially the further North you are. Having something like this occur about a month later would perhaps still be ideal. But it’s something to get the cold weather fans rock and rolling!

Not perfect, but the 12Z NAVGEM gives a reasonable go at toppling the Atlantic ridge into Scandinavia. Still no match for the 12Z ECMWF, but provides a chilly Easterly flow over Central, Southern and some Northern parts of the UK. Could do with a more favourable angle to that Low Pressure to the West of Iceland (being more negatively tilted) so there would be no danger at all of the Lows piling of top of the Scandinavian ridge, or it getting knocked too far East. But at the same time, doesn’t look like it would bring an immediate return to the Atlantic and it’s Westerly/South-Westerly winds. Plus the Low over Northern Spain would probably help to keep the Scandinavian ridge propped up. Not too bad overall. While there is no guarantees a Scandinavian ridge will result from this Northerly setup (but there is at least some support), do feel it would make a nice change from those times where a Northerly just topples and the Atlantic quickly gets back in!

Hi Leo, There’s a great blog by Nick Finnis (Nick F) here, where he goes into detail as to how a SSW is triggered: https://www.netweather.tv/weather-forecasts/news/8730-sudden-stratospheric-warming-this-weekend-but-what-is-it-how-will-it-affect-our-weather We also have a Learners area of the forum where you may be able to find out further information regarding SSW’s. Feel free to ask any questions in their, but we’re always happy to help. Cheers. Edit: Just noticed CreweCold’s post above. Great explanation and advice he gives too (didn’t realise we still had an actual Stratospheric Warming thread, whoopsy lol)

I’m guessing CW stands for Canadian Warming?

Despite tomorrow looking a bit cooler... ...but with temperatures still into the low teens in South and Eastern parts of the UK, Tuesday and Wednesday look fairly warm: Warmest temperatures over Southern and Eastern parts again. The odd isolated 18, 19, or even 20*C figure could be possible in the East/South-East! Particularly in sunnier spells. Coolest over North-Western areas of the U.K with temperatures in single digits in some parts, particularly over high ground. A bit cooler again in general by Thursday: And more so by Friday as the flow becomes Northerly: Southern areas perhaps clinging onto the mildest conditions. However, it will still feel chillier than what many of us have become used to, especially those exposed to (wintry) showers as well as the chilly Northerly winds. The 06Z GFS UK Maximum Temperature charts were used as an example. Won’t go into anymore detail as the posters in the Short Range Model Discussion thread cover the details of the 0 to 5 day range well (although anyone is welcome to give their owns views of the models at any range in our various Models threads ).

Only a small thing really - as an example for next Saturday during the Northerly, the -5/6/7*C 850 hPa temperatures are a bit less diluted over the U.K on the GFS 06Z, than they were on the 00Z run. GFS 00Z: GFS 06Z: May mean any showers over inland areas of the U.K. having more of a wintry element to them at lower levels. (Still would be very marginal towards coastal areas, though, with the best chance of snow over high ground - especially towards Northern U.K and into Scotland). The potency of the 850 hPa temperatures will, I imagine, vary from run to run with variations of the Northerly likely as it’s still some days away. The distribution of the cold 850 hPa temperatures over the U.K consequently having an affect on how wintry any showers or longer spells of precipitation will be as well as other aspects, such as whether the dew points will be around or below freezing, having evaporative cooling (helped by heavy precipitation), and things like that.

If it’s okay, would like to change my guess to 6.5*C please. Tar!

Must have done at least 47 online matches on the Switch version of Mario Kart tonight . And I think it must have been about 19 times where I made some really silly mistakes. Yep, no doubt a really cold Winter is coming!

Me too! The fact it turned to snow before it got dark made it more impressive. There also seemed to be a bit of sleet overnight on the 30th of that year, too. Having a repeat would be fab! And it shows, even in October, sleet or snow isn’t entirely impossible without the magic -5*C 850 hPa temperature line.

The Northerly would probably be worth it if it became an October 2008-style one.

Do feel it will be mostly a dry month in general with the Atlantic staying in bed. Will go for 6.4*C please. 50mm rain/snowfall. Scottish hills snowfall days: 8 Northern UK snowfall days: 5 Midlands snowfall days: 2 South of the M4 snowfall days: Just a tiny bit of hill sleet

We don’t really allow swearing on the forum to be honest - not just on the model thread, but other areas of the forum, so just a reminder for next time. Cheers guys.

Kinda looks like the Western Atlantic ridge on that run is sticking its tongue out at the Vortex!

Before the possibility of whether a Northerly occurs later next week (could just easily ignore the U.K and sneak off to the East), the models, such as the GFS 12Z, show quite a fair amount of settled weather, with some bright spells at times, especially the further South your are in the U.K. All thanks to High Pressure not wanting to give up the ghost! However, with the High Pressure becoming more focused to the West or South-West of the UK towards next week, the best of the driest, brightest conditions will probably become more concentrated over South-Western areas. Mild (and perhaps warm) at times in sunnier periods. And again, especially towards the South and generally a little bit cooler towards the North. But chilly with some frost and mist at night (especially helped by the fairly slack flow at times). Somewhat windier over North-Western UK in general. Some rain likely this Sunday, mostly over Northern and Western parts of the U.K where it will be the heaviest, as shown on the GFS UK Precipitation Charts. Still looks as though the rain will lose some of its power as it pushes South-East through the U.K. Southern areas unlikely to see much rain at all. Beyond mid-next week and it may turn much chillier with High Pressure amplifiying in the Atlantic. But gonna put the lid on things regarding that in here for now, what with this being the general discussion thread. Apart from that, looking quite calm and settled, especially for Southern parts, for the next few days or so. Pretty amazing, really, the intensity of that High Pressure system. Some great weather for some long strolls (if that’s your sort of thing!) ??

It could do with a bit more cold ramping to be honest... But nah, it’s fine. After all, some of those ECMWF clusters at the top of your post do show a possible cold plunge for the UK with some kind of Scandinavian/European troughing.