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Well 06z shows the cold shot, trough disruption and then a reload down the line. Lovely run and as I said I’m looking for a month of several attempts with a theme that the cold pattern then dominates and takes hold as we get deeper into Nov towards the end for a cold themed December. It’s miles down the line....but we look like we on our way with interest. My current country file calendar on October has a bull looking over Loch Lomond with snow capped mountains. That scene will be repeated very soon. Lovely BFTP

And increasingly IMPRESSIVE nor-hem profile... A truly exiting set up.....

It’s amazing the lack of drama with this northerly ! The models have counted down without a last minute curveball thrown in ! I know most attention is on the northerly but after that what happens to the east and is it possible to get some snow as the Atlantic tries to move in. It would be exceptionally rare to get frontal snow this early in the season. I still think that’s a long shot . Preferably that low near Iberia needs to be further east to stop any milder Med air getting thrown too far nw. So as much as people are looking to the north , later on dew points temps over northern mainland Europe are the area to watch in case we see better trough disruption to the west .

24 hours of the GFS Image 1 - 12z T150 today Image 2 - 12z T174 yesterday Note the clear move to the -6c & -8c isotherms covering a wider area & them both being closer to the UK... Possible snow event in the offering as the atlantic approaches....

Back to the model output and the GFS is not backing down from the very cold uppers, may see some lower lying areas see some snow/wintry showers. Meteociel precpitation forecasts suggest so! Perhaps Wales and Scotland could do pretty well? Maybe a bit of sleet in some of the east coast showers? Impressive early cold pool over Scandi on Monday. A few people saying they are worried about getting cold synoptics now. The weather does not have a budget, the weather gods don't think 'Ah I used up 6 easterlies in November so I won't use any more for the winter'. The weather will do whatever it wants and all we can look at are long range signals for an inkling and hope they persist into the short range. Enjoy the ride. Look at November 2010 or November 1878 for blocked Novembers leading to very good winters.

Wow, amazing synoptics for the end of October. This crazy year continues to produce extreme conditons . Temps of 10c or more below average next weekend over much of Western Europe, with extreme values over Iberia. On the other scale, plus 10c above temps over parts of Eastern Europe and Central Europe for a time. Forecasting snow to rain and the other way round is going to be very difficult as the very strong baroclinic zone formulates across Europe. The map below shows unusual October snow cover forecast for parts of the UK . We in the Alps will have a nightmare scenario with heavy rainfall values forecast of over 60mm that may or may not change to snowfall . At this stage , the Western Alpine regions look prone to be covered in the Arctic mass and risk of some heavy snowfall. However, here in the Eastern Alps , borderline. Its going to be fun next weekend from a weather forecasting prospective and we over here will have to rely on our short range fine mesh model to forecast snow with height nearer the time. However, I think we can all expect some unusual weather, just has 2018 has already delivered to many. Will get back later with thoughts from our experts over here. C

if we are going to be analysing individual ensemble members on each run in the search for wintry sypnotics then this thread could become the largest NW one ever !!

Hi All, I'm looking forward to our first cold snap after a stunning summer, let's hope it's the first of many! Would imagine the high ground of Northern England and Scotland especially will fair best for the white stuff this time round, but noticeably colder for everyone! Certainly going to notice that wind chill on Sunday when I'm stood on the side of a football pitch. Bring it on!

The issue is that year on year some people don't learn. Cast your mind back to November 2016- everyone was getting giddy about a 'disorganised vortex' and blocking- even the Metoffice were going all in on a cold December. The issue was, like now, there were an abundance of factors which suggested mild- not least the fact the zonal winds in the strat had reached heady figures. The only thing that kept the trop PV in a ragged state through November that year was the strat-trop disconnect. Towards the middle of that month, the modelled Greenland high pressure failed to assert and was toppled...from that point I knew it was game over- and it was. The strat and trop coupled. All the abuse I received that year when I was warning people not to get excited...Believe me it would be so much easier to sit here telling everyone how cold it is going to get and how many snow events we are going to be seeing, lapping up the 'likes'...but I'm a realist I'm afraid. It would be ludicrous to suggest winter is over in October...my post was merely suggesting we need to keep a blocked pattern going as long as possible in the locations that count (which won't necessarily benefit the UK in terms of cold right at this moment). I feel a key requisite this year will be a Canadian warming early December.

Step in mate,destination time>November patience Dan,i know we haven't got much of that and it is the same every year but still a long time to go,it is better than nothing to see these synoptics so early in the season than the atlantic dross we have endured so many a year prior to the winter season, i know things can drastically change for the worse if the pv ramps up but it took a huge blow early this year and i hope it has still got deflated gloves on. let's have a look at some synoptics and charts etc:- here is the latest from the cpc 500mb outlook days 6-10/8-14 mean anomoly's,the chart up to ten days shows trough(low) over Iberia with a Scandi hp(high pressure) cell with some sort of flow from the east but the upper flow shows some sort of trough disruption if i am reading that properly,the chart up to 14 days not too disimilar to the first,subtle difference is the trough out of SE Greenland moving on a SE trajectory with height's building north of that into greenland,ok i am talking into too much detail as they are anomoly's but that is how i see it The ten day mean charts from the ecm/gfs are pretty similar with one another with the pv(most of it)parked over towards the Siberian side(this is a good thing) with displaced Azures hp cell well out SW and trough disruption against the block to our NE,below are the ens 850hpa temp graph's from ecm/gefs and as you can see from the ecm ens the cold has been extended a day(left one from the 19th compared to todays on the right) and finally these little fella's maybe paying a visit this weekend to enjoy what's left of our summer barbeque's oh wait!!!,the ecm is showing a spanish plume later next week,com'on guy's we are off.....

Yes a couple more runs & it will get the slide more defined- still in the GFs unknown zone atm- its like where shall I place that energy- I know EVERYWHERE...

Look at that NH view, no PV gaining strength just yet - In fact how often in late Oct can you make out the outline of Canada like this. Interesting times, may come to nothing but nice to see.

P1 scandi high with hints of retrogression P5 P15 P19 ECM

upgrades to the "slider" seem to be stepping forward bit by bit as each model run roles out - let's see where we are in a day or so, could be very interesting

Well I think it's about time I shifted from summer to winter mode. Good to be back on the thread and it's great to see lots of familiar faces ready for another roller-coaster ride for winter 18-19. Having not looked at the charts for a week or so my jaw dropped a little looking at how next weekend is panning out. Stunning charts for next Saturday with a long-fetch northerly. Unfortunately about 4-5 weeks too early for anything meaningful away from the tops of the mountains, but certainly something to whet the appetite! Good to see a lot of cold and snow for Scandi and the Baltic states as well. Here's to a repeat of Feb-Mar 18 please.

Thanks @Interitus great shout re: Panoply - now for IT puzzles to get it to work - admittedly am about as impatient and as crap with this stuff as I am with excel.. especially when it serves up random error messages. Speaking of excel - here are a couple of plots of all SSWs - first plot shows the dates demarcated by the red dots, then SunSpot activity / QBO regime and ENSO regime. Second one is SSW via SSN scatter alone - limited pattern there with outliers. Both give a view of all the SSW activity from Butler's table in visual format.. will leave the conclusions to everyone else !

P1 with a near split in the pv (what there is of a pv) P3 P7 gets close to a boom chart with the blocking to the west of greenland/ canada forcing the cold to our side P18 the best of the bunch

Great chart at 168 by the ECM, a tweak here and there and it’s a beauty! Some brutal cold for the time of year in Scandinavia

Scandi High. Massive trough disruption. No Vortex in sight. Basically zero model drama or shortwave drama. Bloody hell why is it only October.

Howdy. Time to switch the lurking mode off. Wind has more of a bite to it these days, the white stuff doesn’t feel too far away. Nice moody sunset towards the monadhlaiths last night while out with the dog

The outlook initially remains unchanged for this period with high pressure generally in charge but, as previously mentioned, the position and orientation is such that that the north, particularly Scotland, is still susceptible to systems running around the northern flank of the high cell, But towards the end of the period this changes very quickly, courtesy of upstream developments, and much colder air plunges south over the UK down the eastern quadrant of the burgeoning subtropical high in the western/central Atlantic. The 500mb and surface analysis for midnight and the 0300 WV image After a pretty clear night over much of England and Wales. a little more cloud further north. it will be a dry and sunny day in many areas, albeit not overly warm, but rain will effect the north of Scotland as a front skirts the coastline and the wind will pick up during the day and will touch gale force over Scotland. During the evening and overnight further rain over north west Scotland but the main feature is the strong wind, still touching gale force which has veered north westerly and moved south to also effect the north of England. This is pretty much the story through Tuesday with rain across north west Scotland and continuing windy in the north with gales in exposed areas. Further south continuing dry and sunny and perhaps warming up a tad. Wednesday sees the start of the transition with developments in the western Atlantic but the immediate effect closer to home is to realign our high cell which becomes more influential, thus winds abating in the north and resulting in a generally fine day with sunny intervals and relatively warm. Still some patchy rain across the west coast of Scotland By Thursday the transition is well underway with the trough over the eastern seaboard initiating rapid amplification of the subtropical high in the western Atlantic which in turn facilitates the trough and cold air to plunge south to the north of Scotland. So that by midday the cold front is just about across the north coast of Scotland. Thus rain will spread down the west coast and to N. Ireland during the afternoon whilst the rest of the country again remains dry with sunny intervals. Overnight and through Friday the cold front will track south reaching the south by the afternoon leaving in it's wake much colder air in a very strong northerly wind which could touch gale force in the north and north east. In this very unstable air frequent heavy showers will develop which will be wintry in the north with snow on the high ground and possible even at low levels. It goes without saying it will feel very cold. And the NH profile at T120 sums it all up

Yup....i realise.there the 18z..from the run previous!.. So i highlighted/posted for tonights compare.....18z...pattern/diverse. PS:.. if you 'cannot' decipher/understand that...-in PLAIN ENGLISH-.... then i concern about your divulge!!!!!! Chucking in the 500 geo-pots.. and they are of align....'in a sort' !!!

In English? You may want to check the date of those ensembles ?

Unbelievable ? One of the longest draws out of deepest Africa ever ! Turn off the heating again ? C

Had the most amazing gnocchi ragu in this tiny family run place in Venice. They spoke no English, I spoke no Italian but that was one of the best things Ive ever eaten.

A lot of similarities to 2010. More so to note the SE Europe warmth, I remember early November 2010, Cyprus and parts of Greece were still recording 27-28c maxes. This type of pattern will favour low pressure development in the Med and Central Europe, which is certainly better than a Eurotrash high, like October 2006 and 2011.

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!

Well that PV looks well mangled! ECM at T168. And here at T192:

I share other people's fear on here that these amazing synoptics for cold have maybe come a bit too early...but you never know. It has been a strange year for weather & something has definitely impacted upon the coupling up of the stratospheric and tropospheric vortex in recent years. Looking at the charts, I can see there's a lot of Alaskan / Aleutian high pressure reaching right into the Arctic. Is this what we should be watching for in the next few weeks if we want a continued disruption of the polar vortex & a possibility of a canadian warming? TIA David, Northallerton

Yes - look at the small low over Iceland, now a nice negative tilt on it even compared to 6z with better trough disruption and a better dig south with a better orientated scandi high.

Lovely amount of blocking over the arctic. Virtually a split vortex

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!

Thank you for your work Lorenzo. I am tho a bit confused with the first plot. The enso regime from 1990 to 2001 seems quite off, being all in negative? I did one a while ago, I guess I should update it and add SSW dates. Black line is ENSO.

I agree to an extent. What is important at this stage for 'jam tomorrow' is that the models continue to show the beaten-up shredded trop PV, a la ECM T168. Whether that means a cold blast or warm southerlies for the UK at the moment is moot, as far as I'm concerned. (My location may mean the difference between cold rain and mild sunshine, I know which I prefer - the stakes may be higher further north, I know!) Total disconnect between the strat and trop vortexes at the moment, and modelled in the reliable. I've got a nervous eye on this as we move forward into November, as it is the thing that can make or scupper this front loaded winter idea...is it simplistic to boil it down to 3 possibilities? 1. Early strat warming aka Canadian warming, increasing likelihood of Dec cold. 2. Marmalised trop vortex holds off down welling from the strat - result possibly even increased likelihood of UK cold in Dec. 3. Strat vortex wins as of Dec 2016, game over. I would really struggle to put probabilities against these at the moment, but I'll have a go and others can offer opinions: 1. 20%, 2. 55%, 3. 25%.

I could swear it looks like a southerly to me and a possible return to the high teens in temperatures But pure la-la-land at the moment, the kind of synoptics coming up are the ones most likely to throw up unexpected model runs as early as D5.

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).

Interesting jet configuration around the amplifying trough/ridge complex stretching from N. America to the UK on Saturday. Cetainly some snow on the higher ground down to Wales I would think and even low levels in Scotland.

Its coming out now - 16.30 to 1800 - changes next weekend though - an hour earlier. This is where its up to now.

Still undecided on the PDO but if you go for solar, weak Nino, standardised Qbo of +1 for Q1 months and just go with Q3 PDO analogues then the strongest matches are 2003, 2005, 2009 and 2010. 2002 and 2004 are good enso-pdo matches, 2009 is a good solar-pdo match, 2008 is a good solar-qbo match. Very strong signal for Jan cold, Feb and March less so due to high pressure closer to the UK but Feb 05 and 09 both had easterlies. March 03 and 05 also hit 20C.

Given the time frame a reasonable agreement between the mean GEFS and EPS anomalies this morning. Which suggests unsettled weather with surface temps remaining below average. And last night's NOAA is in the same ball park

Lovely and sunny, 11C...Whatever happens, I think we might be in for some pretty good sunshine totals. Again!

Another very nice day here, after the cold front passed through overnight with a little rain. Feeling cooler at 13C but with light winds and nearly clear skies.

The weekend firming up more and more on the cold snap I suspect the ECM is overdoing heights into Scandi after that, time will tell, but I think more likely that the incoming low at D7/D8 will be a direct hit on the UK rather than passing to the south. Scotland could see significant snow from this second event if it can draw in enough cold from a freezing Scandinavia, though cold rain probably the favorite considering the time of year.

The end of this month appears likely to be quite cold, so I had a look back through the daily data series (1772 to present) to find the coldest periods from 26 to 31 October (when it's going to be coldest) then what happened in the five months after that. These are the results (coldest 22 cases are shown, together with the three coldest since 1981 as coldest of those (2008) was tied 22nd -- the ranks overall include years not shown before 1981 -- the fourth coldest since 1981 was 6.42 in 2003 which was quite a gap from third relative to the longer series). After that, if a winter in the coldest ten (since 1772) did not show up in the list, I show the average temperature for 26-31 October before those very cold winters. Anything that happened before 1772 is excluded since we only have monthly averages. (note: the rank for the winter is based on DJF only and as there are 246 winters to rank (1772-73 to 2017-18), the result is presented as either part of the 122 coldest or 124 warmest (five tied for 120th warmest) (from Hadley seasonal CET rankings excluding earlier than 1772-73, a compilation of which has been saved, ask if you want to see the rankings of all 246). Rank _ Year __ 26-31 Oct ___ NOV_DEC_JAN_FEB_MAR __ Rank DJF (adjusted, excludes 1659-1771) _ 01 __ 1895 ___ 2.08 _______ 7.5 _ 3.9 _ 4.8 _ 4.6 _ 6.7 ___T-88th warmest _ 02 __ 1836 ___ 3.25 _______ 5.3 _ 4.1 _ 2.7 _ 4.7 _ 2.3 ___T-108th coldest _ 03 __ 1896 ___ 3.30 _______ 4.3 _ 3.9 _ 1.6 _ 5.8 _ 6.5 ___T-101st coldest _ 04 __ 1922 ___ 3.52 _______ 5.9 _ 5.8 _ 5.6 _ 5.6 _ 6.5 ___T-21st warmest _ 05 __ 1813 ___ 3.73 _______ 4.3 _ 2.8_--2.9 _ 1.4 _ 2.9 ___ 2nd coldest _ 06 __ 1873 ___ 3.87 _______ 6.3 _ 5.3 _ 5.5 _ 3.9 _ 6.7 ___T-59th warmest _ 07 __ 1909 ___ 3.88 _______ 4.8 _ 3.9 _ 3.5 _ 5.1 _ 6.1 ___T-112th warmest _ 08 __ 1926 ___ 3.93 _______ 5.9 _ 4.2 _ 4.6 _ 3.9 _ 7.3 ___T-107th warmest _ 09 __ 1881 ___ 3.95 _______ 8.9 _ 3.9 _ 5.2 _ 6.1 _ 7.4 ___T-50th warmest _ 10 __ 1950 ___ 4.25 _______ 5.7 _ 1.2 _ 3.9 _ 3.7 _ 4.1 ___T-55th coldest _ 11 __ 1931 ___ 4.48 _______ 7.8 _ 5.3 _ 6.3 _ 2.9 _ 4.7 ___T-63rd warmest _ 12 __ 1819 ___ 4.50 _______ 4.1 _ 1.4_--0.3 _ 3.2 _ 4.7 ___T-11th coldest _ 13 __ 1785 ___ 4.57 _______ 5.6 _ 2.8 _ 2.7 _ 3.4 _ 2.1 ___58th coldest _ 14 __ 1810 ___ 4.60 _______ 5.4 _ 3.6 _ 1.2 _ 4.6 _ 7.1 ___T-66th coldest _ 15 __ 1955 ___ 4.80 _______ 7.0 _ 5.4 _ 3.6_--0.2 _ 6.2 ___T-55th coldest _ 16 __ 1797 ___ 4.87 _______ 4.7 _ 4.8 _ 3.6 _ 4.0 _ 5.1 ___T-116th warmest _ 17 __ 1917 ___ 4.92 _______ 7.8 _ 2.3 _ 3.8 _ 6.5 _ 5.7 ___T-110th warmest _T18 __1919 ___ 4.93 _______ 3.3 _ 5.5 _ 5.2 _ 5.0 _ 7.2 ___ 26th warmest _T18 __1939 ___ 4.93 _______ 8.7 _ 3.2_--1.4 _ 2.6 _ 6.0 ___T-13th coldest _T18 __1948 ___ 4.93 _______ 7.3 _ 5.7 _ 5.5 _ 5.7 _ 5.1 ___T-23rd warmest _ 21 __ 1869 ___ 4.95 _______ 5.8 _ 2.9 _ 3.3 _ 2.8 _ 4.7 ___59th coldest _T22 __1880 ___ 5.00 _______ 5.4 _ 5.1_--1.5 _ 3.2 _ 5.3 ___T-28th coldest _T22 __2008 ___ 5.00 _______ 7.0 _ 3.5 _ 3.0 _ 4.1 _ 7.0 ___T-89th coldest _ 24 __ 1997 ___ 5.05 _______ 8.4 _ 5.8 _ 5.2 _ 7.3 _ 7.9 ___ 10th warmest _ 28 __ 1992 ___ 5.35 _______ 7.4 _ 3.6 _ 5.9 _ 4.6 _ 6.7 ___T-72nd warmest _ medians of all 25 years ^^ ___ 5.9 _ 3.9 _ 3.8 _ 4.1 _ 6.1 ___T-116th warmest 26-31 Oct before the rest of the ten coldest winters ... _ xx __ 1962 ___ 6.50 ________ 5.5 _ 1.8_--2.1_--0.7 _ 6.0 ___ coldest _ xx __ 1794 ___ 7.30 ________ 6.1 _ 3.7_--3.1 _ 0.8 _ 3.9 ___ 3rd coldest _ xx __ 1878 ___10.38 ________ 3.5_--0.3_--0.7 _ 3.1 _ 4.7 ___ 4th coldest _ xx __ 1829 ___ 6.12 ________ 4.5 _ 1.4_--0.2 _ 2.2 _ 7.7 ___ T-5th coldest _ xx __ 1946 ___ 5.73 ________ 8.1 _ 3.1 _ 2.2_--1.9 _ 3.6 ___ T-5th coldest _ xx __ 1783 ___ 7.00 ________ 6.2 _ 2.7_--0.6 _ 1.4 _ 2.7 ___ T-7th coldest _ xx __ 1894 ___ 9.35 ________ 7.9 _ 5.1 _ 0.2_--1.8 _ 5.1 ___ T-7th coldest _ xx __ 1784 ___ 6.38 ________ 5.5 _ 0.3 _ 3.4 _ 0.4 _ 1.2 ___ 9th coldest _ xx __ 1837 ___ 7.82 ________ 5.2 _ 5.3_--1.5 _ 0.4 _ 4.9 ___10th coldest ___________________________________________________________________________ The winters that followed colder periods 26-31 October averaged out close to normal (for the longer-term considered) but there were some quite cold winters and the general tendency before a cold winter seems to be for the period to be average to rather mild (as shown at bottom of the table).

Yes I think in 2016 people thought it was certain we would be getting cold synoptics because all the longer range forecasts were indicating cold but that counts for nothing until we get into medium range, it's just an inkling. I think last winter was different because we had a big SSW event and this has a plausible mechanism for causing northern blocking. Saying that though a strongly negative NAO in November does seem to improve our chances of cold in its first half but not by a huge amount. I also look out for cold shots reaching the SE US and very mild air getting to Newfoundland and Greenland. SSTs are also worth keeping an eye on, here are a comparison between milder winters and their November SSTs Milder winters 2015 2013 1994 2011 Colder ones 2012 2010 1996 1995 From the examples it seems as though warmer then average SSTs around the east of Newfoundland, around Greenland and the tropical north atlantic but it isn't clear cut. What at 2018? Here is the picture from the latest SSTs.... Seems like an SST profile that would favour a more westerly jet so the southerly flows in the Central North Atlantic region would be nice. As would be some cold pooling in the SE US/ Gulf of Mexico which is what is happening this week. So the northerly next weekend is welcome IMO. 18Z not much different from the 12z upto the medium range.

Can we turn the clock forward a month ! A great set up just a little bit too early . The models are in very good agreement for the initial cold snap . The Scandi high development looks more likely today as the PV looks weak with the main energy heading se to the west of the UK . Overall it looks like a Canadian style change from warm autumnal conditions to cold bypassing the more mediocre bit in the middle . Some early season snow for higher elevations in the north , still not convinced of anything more widespread given how early in the season we’re seeing this good set up. I wouldn’t look further than day 8 , a lot going on and the models look a bit of a mess after that point .

What post northerly? well the GFS 18z has the strongest signal yet from the runs I've seen for a Scandi high, here at T204: Jet stream at same time: Small steps, need the strat to get on board at some point, though. No immediate hurry. Edit, by the way, anyone else think the T240 chart has an air of implausibility about it?

Been away in Blackpool for the weekend, lovely sun yesterday but cloudy and rain today, however the sun came out just in time to show us a beautiful sunset view.

ECM huge Scandi block & a possibly big wintry event @168

What a glorious weekend it's been, not that I've been out in it much, far too busy sewing at this time of year. The forecast next weekend....that'll be a bit of a shock, doubt we'll see anything wintry down here but it'll be a lot colder than of late and it has inspired me to make a snow queen this weekend, so not all bad.