stodge

Evening all Yes, it's Birthday Watch time as I count down the charts to my big day on January 15th. Starting with ECM - taking the 12Z OP charts for (respectively), T+240 on the 5th, T+216 yesterday and T+192 today: While not as vigorous as the T+240 chart, tonight's chart looks quite similar and has the main LP diving SE across northern England so a pretty unsettled day with rain or showers and perhaps something more wintry for the far NE of Scotland and the Northern Isles. GFS - some rules apply: A gradual shift north in the past two days. At T+240 the core of the LP was south of Iceland, now it is just west but a fraction deeper. Showers and a chilly PM flow look on the cards. GEM: As with the GFS less sense of the core of LP diving SE but still fairly chilly PM air over the British Isles for my birthday. Both GFS and ECM much less keen on northern and north-eastern heights than ECM at this stage. I'll add some more output in the next post.

Evening all It's my new favourite time of the day (though probably not anyone else's). Birthday watch - charts for January 15th taken from the main 12Z OP runs now at T+216: ECM: - today's 216 and yesterday's T+240: GFS - today's 216 and yesterday's 240: GEM: - same again Fascinating to see the story develop - ECM and noticeably GFS "slower" to bring the large LP down through the British Isles but GEM a little different with orientation. I'd also note the height profiles to the north - ECM looks the cleanest today with as usual GFS hinting at conveying more energy to the north east. Let's see where we are tomorrow.

Evening all Birthday watch for me starts here: GFS 12Z OP at T+240 ECM 12Z OP at the same time: GEM 12Z OP at the same time: Quite like the model agreement and I get a chunk of polar vortex for my birthday. - let's see where this goes.

It's my birthday on the 15th and all I've ever wanted is a chunk of the Polar Vortex: Uppers below -4 in that so you'd think snow for some particularly with altitude. I've been on this earth nearly 57 years and the number of years I've had snow lying on my birthday - 3 or 4 at most.

Morning all Oh dear, it's all doom and gloom here this morning, isn't it ? We aren't even half way through winter and you'd think we'll never see a frost let alone a flake of snow again. It's not a question of "learning lessons" and being all "I'm not believing it until every model agrees at T+3" - fine, but it'll be a grumpy old place if we all thought like that. It's chaotic science at best looking 6-10 days out - the Ens are helpful because there are more attempts to get it right - think infinite number of monkeys and Hamlet. Anyway, before the Mods throw me off for hesitation, obfuscation and obstruction, my take on where we are this morning looking forward: ECM goes for a full Atlantic breakthrough and a serious old storm at T+240 but we can probably ignore that. Neither GFS 00Z OP nor GEM bring the Atlantic through in strength and indeed the HP rallies later next week so could be quite a quiet, chilly spell for southern and eastern parts in particular. The other observation is the continued negative tilt in the trough going forward so it's less a case of positive tilt and blowtorch SW'lies than back to square one with the jet running over or just to the south so while I wouldn't call it "cold zonality", the periods of PM air are and would be noticeable but not what most want. UKMO at T+144 looks worrying as the Azores HP is coming in and the trough is tilting positive but we'll see and I also note the GFS 00Z OP scrubs the PV out of NE Canada by the end of FI and I wonder if that could be the next direction of travel in 10-14 days or so. Until then, after our brief flirtation with something colder and drier we have to accept that in the words of the song "all we can do is just sit and wait". There's plenty to look at and the medium term is far from resolved this morning.

I don't think there will be a classic "breakdown" at all. I begin to suspect we will enter a rather quiet period after the weekend as neither the HP to the east nor the LP to the west will have enough influence to fully take over. We'll have dry if chilly days and some night frosts and fog before a gradual lifting of temperatures from the west in the latter part of the week.

Morning all Plenty of people up and about at ungodly hours to catch the 00Z output it would seem. GFS 06Z OP at T+174. The one thing it doesn't show is a raging Atlantic breaking down a Scandinavian HP block. The orientation of the HP block isn't of course what many on here would like but it reminded me of the ECM 00Z OP output this morning at the same time: I wouldn't call it cross model "agreement" but those who argue that model A is "moving toward" model B have something to hang their figurative hat on. The ECM wasn't inspiring after that but as we've seen the journey begins with small incremental types. Steve Murr has been adroitly pointing out how the GFS has watered down its earlier Atlantic onslaught and now it's a half-hearted weak push with barely enough to get past the meridian. I begin to suspect this cold "spell" or "snap" won't have the quality many on here seek but may have a shade more longevity.

Evening all Plenty of angst and anguish on here tonight - not sure why: ECM 12Z OP T+240 from last evening: ECM 12Z OP T+216 from tonight: GEM 12Z OP T+240 from last evening: GEM 12Z OP T+216 this evening: GFS 12Z OP T+240 last evening: GFS 12Z OP T+216 this evening: Confused ? You will be - as GFS quietens down the Atlantic, ECM springs a dartboard LP of the kind we saw from GFS earlier in the week. GEM tilts the HP from the Azores toward Greenland - retrogression anyone ? As others have said, getting agitated over intra-run variations is, as Chris Rea once observed "the road to hell". I've no clue.

Afternoon all An excellent analysis as always, Catacol, for which many thanks. My expectation however is as the MJO moves into phase 4 or 5, the Azores HP will come back into play and we will have to endure/enjoy (delete as appropriate) a milder interlude of Atlantic domination before, as it hopefully quickly and with amplitude moves into 6/7 and perhaps 8, it will be much better news for those seeking colder weather.

The key difference between the ECM/GEM and GFS lies further south. The former keep the LP and lower heights around Iberia and southern Europe but the GFS quickly removes them changing the orientation of the HP significantly to a SE/NW shape which brings a modified Atlantic flow back over the British Isles. As a tiny step in the right direction, the HP is stronger and the Atlantic weaker so some progress.

Morning all From my IMBY-ist perspective, slightly more concerned by the track and intensity of Friday's feature - not as vigorous as Eleanor it would seem but likely to bring a period of heavy rain and strong winds during daylight hours on Friday so another "event" to consider.

Evening all First, New Year greetings to all on NW and especially to the various admins and mods who keep the show on the road. ECM 12Z OP is nice to look at - the NW winter forecast was tiled "winter on a knife edge" and this is one of those knife edges it would seem. Signs at T+216 of the energy perhaps heading more SE than NE and that's what we need if we have any chance of this next cold outbreak becoming a "spell" rather than a "snap". T+240 delivers in spades: I'd go further and say this is the chart of the 2017-18 winter to date because IF (and that's an enormous IF) it verifies, the heights to the NE will have a chance to build and develop. It's nice to say the possibility being mooted but there is an enormous amount of water (whether ice or with some scotch in it) to flow under the bridge but it offers something unusual and different.

Morning all Another day, another set of interesting output and I imagine plenty on here will be hanging their Christmas hats on the ECM/GEM 00Z solutions which loom remarkably similar to this observer while GFS is in a very different place. Here's GEM for North America at T+192: I think they call it a "Nor'Easter" over there and would be a classic blizzard. The storm ambles NNE and this slowdown of energy out of the CONUS has huge downstream impacts. ECM 00Z OP at T+192 for North America: The storm is shallower and therefore moves more quickly but it does allow downstream amplification. GFS 06Z OP at T+186: Storm ? What storm ? No storm means the current mobile set up continues with LP formation in northern Canada and secondary formation further south.

Both GFS and ECM have tried to send the Azores HP NE and turn the trough to a positive tilt consistently and persistently in FI but it's not amounted to anything so far. The models have tried to dig the trough to the west of the British Isles but if anything the reality has dug the trough into Europe leaving the trough negatively aligned and more PM air in charge. Why this has happened I don't know but I wonder if it relates to the overall pattern of the PV. The lifting of heights into Europe could be a precursor to a pattern change leaving Europe more anti-cyclonic - that was being posited from early in the New Year but remains the preserve of a minority of members at the edge of FI. For those wanting cold (which I know includes you), the pattern is indicative of something we've not seen for a while and is rather different than hoping against hope for a Greenland or Scandinavian block and a 7-10 day severe spell followed by a thaw as the block breaks down. A PM-based set up (aka cold zonality to its friend) can deliver persistent snow almost anywhere though areas with altitude further north will always do better in that regard. The problem with the southerly tracking jet for those of us in the south will be wind and rain as I'm sure you are already well aware.

Morning all "Remorselessly Unsettled" is how I would describe the 00Z output. Both GFS and GEM begin the New Year with a very disturbed theme with a train of secondary LPs taking various tracks across the south and the midlands. The GFS rainfall numbers tell the story: Note the south and woodshed areas copping the most water. Both the OP and Control on GFS try to build the Azores HP further north as the jet shifts back north into the second week of January but to be fair we've seen this before and it hasn't happened so if we're talking T+324 and beyond certainly not one to believe too strongly at this time and at that time plenty of options in the GEFS as you would expect.

Yes that's the message from the 12Z output as I see it. Short milder spells alternating with longer spells of PM influence. Plenty of support at the very end of 12Z GEFS for a return of blocking to the north and east but we'll see.

Morning all Merry Christmas to all on here. Have to say the 00Z GEFS weren't without interest but we're a long way from a pattern change as yet it would seem. Rainfall accumulations on the 06Z OP worth a look - might be some concerns in some areas.

Afternoon all We're not even a third of the way through winter and the usual old moaners and miseries are on complaining about the absence of 20 foot snow drifts outside their back door, storm force easterlies and minus 20 uppers at T+6 which will no doubt get downgraded.. I'm nowhere near as pessimistic even though it's entirely possible I've had my snow for the winter here in lowland East London. As I keep saying, the route to very cold starts from very mild and there may well be a period of pain to endure before the result so many on here want. The GEFS shows a (to me) growing cluster offering heights to the NE into the second week of January and this was the time scale advertised initially by those who argued for a typical Nina winter. I hoped for a 10-14 day milder interlude but have always suspected it could be nearer 28 days before the pattern changed or relaxed sufficiently to break the Atlantic and let other influences gain some traction. The build of heights back into Europe and the evolution of a blocking HP (favourably located in time) seems that route while the continuing pattern of a southerly jet and colder outbreaks of PM air will no doubt deliver transient snow to many (and rather more to hose with altitude in the north) it's not, I suspect, what many really want. The synoptics to deliver a 10-15 day nationwide very cold spell with snow don't happen often - the fact we remember the times when they do speaks volumes - but they've happened more often further into winter than now. To seemingly right off the season before we're even one third of the way through and especially when many have seen snow lying seems curious. The 12Z suite yesterday was excellent for cold weather fans - let's see if this continues and no doubt someone will jump in at T+96 and declare the run useless because one LP is 50 miles further north.

Evening all The big development on the 12Z suite is the failure of the trough to dig south and promote heights over Europe. The positively aligned trough brings back the milder SW'ly winds but with the trough not moving and the jet keeping to the south it's plenty of cold rain for me and the possibility of snow (probabllity for most high ground and certainty for the Scottish mountains) for those on lower ground further north. I have to say looking at the ECM 12Z T+240 chart I'm not seeing a raging Atlantic either.

As I've often said on here, the route to very cold starts from very mild. The scenario of HP developing in Iberia and moving NE into Scandinavia is one we've seen before - I believe that's how the 62-63 winter got started. It doesn't happen often - usually we get MLB rather than HLB as the northern arm of the jet has enough strength to hold the HP to the south so it gets as far north as Germany or southern Denmark. Now, for those of us in the SE that's no bad thing if you want cold because even an MLB with the right orientation can bring colder clearer air in from the Continent. Obviously, fans of snow would need an HLB to deliver anything more than snow grains and snizzle. The current output suggests nothing more than a transient MLB at best but it's very early days and a direction of travel mentioned by a number of forecasters in their LRFs. I did think yesterday the signal for sending heights back into Europe had been muted or perhaps delayed beyond New Year - this morning I'm not so sure.

Evening all Not exactly in our neck of the woods but picking up on something Nick mentioned: Seriously high pressure over much of North America centred over one of those Midwestern states (Kansas, Nebraska, Iowa perhaps ?) Wouldn't that inhibit the usual progression of weather systems across America and beyond ?

Afternoon all The "problem" at the moment is all the output breaks down the current HP around Christmas and this allows the jet to sink south and LP to cross the country as the Azores HP becomes displaced and suppressed but the HP quickly regain strength and moves back east into Europe turning the trough tilt positive and re-introducing milder SW'ly winds around New Year. There are, it has to be said, signs that may also be a transitory effort as the HP heads east into central Europe. The "alternative" scenario has the Atlantic trough digging south and splitting the HP - one part retreats SW into the At;lantic while the other moves east into Europe and again draws in a mild SW'ly flow. Even if the centre of the HP is far to the west or SW, there is often a ridge thrown back toward Iberia or Western Europe to maintain the heights over Europe.

Evening all As is often the case with winter, hints and whispers on the edges. The problem for me looking at the post-Christmas evolution is both ECM and GEM send the HP back into Europe re-tilting the trough positive and sending back milder SW winds. If that can be halted or reduced and the Azores HP kept suppressed far to the SW, it looks more interesting for cold as the negatively-tilted trough and the southerly tracking jet offer plenty of opportunities for those to the north and with altitude. I've probably had my snow for the winter here in lowland East London - or have I ?

Evening all Plenty of interesting model watching currently and it could well be midweek before the far south and SE see a significant warming in temperatures so while it's no 2010, December 2017 may well turn out colder than many of the more recent examples. A lot of agreement on the 12Z output tonight - HP builds in strongly from the SW from tomorrow bringing much milder SW'ly winds to northern parts of the British isles but with quite an intense HP (up to 1045MB) sitting just to the south, the far south has lighter winds and a greater risk of frost and fog and with the nights almost as long as they can be there's a chance that fog could linger in favoured spots. The HP begins to withdraw steadily later in the week as stormy and vigorous LP start to move south and SE - here's ECM for Boxing Day: GFS 12Z OP angles the LP differently: The Control takes it even further: The idea of NE heights remains at the far edge of FI (basically around New Year) but for Christmas Day the cold ship has sailed in my view. ECM and GFS OP FI bring the jet south and allow much stormier and more unsettled conditions to sweep in from the Atlantic and that looks perhaps the "form horse" for the immediate post-Christmas period and if you are a coldie, remember always the route to very cold begins from very mild so a blowtorch Christmas Day with the HP building through Europe to the east may pay dividends at New year but the Atlantic looks to be in a strong phase at present and my view remains we are now entering a 10-14 day (minimum) period of Atlantic domination but that will still leave a lot of winter.

Following on from the 00Z OP and Control. Yes, we do need a shade more continental flow admittedly but that looks a good chart for frost and fog in the SE and IF the fog lingers it would be very cold by day - quite possible to have an ice day in London under fog even with very high 850s.