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stodge

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  1. Morning all Been away due to a family bereavement and haven't looked at a chart for 10 days or more. The last I remember was plenty of northern blocking building for later in May with heights to the north and persistent LP over Europe leading to an easterly flow and the risk of showers for southern and south western parts. As a man from Sheffield once said "that was then, this is now". The medium term analysis goes out to Thursday May 31st and starts as always with the morning's ECM output at T+240: Not a lot has changed. Heights over Scandinavia and a notable trough over Europe bring in a warm, if not very warm, SE'ly flow for many over the coming Bank Holiday but the HP retrogresses to Greenland meaning pressure drops near the British Isles and shallow Atlantic systems are edging in to the south west with a cooler NE'ly flow across the far north. Settled for now but the notion of things going downhill at speed is evident. GEM 00Z OP at the same time: Some differences to ECM. Good agreement through the weekend with the warm SE'ly but GEM takes the trough further north across the British Isles before heights rise again to the NW and NE and we end with a light easterly flow but still with a risk of showers for southern and south western areas. GFS 00Z OP at T+240: The HP doesn't retrogress as with ECM but moves back into Scandinavia and declines SE but the pressure gradient over the British Isles is very slack. Some residual LP to the south west but very much a holding pattern with showers possible but very light winds. Further into FI and HP builds to the north and north west so another dose of easterly winds before a trough develops over Scandinavia and extends SW bringing in cooler and more changeable conditions. GFS Parallel at the same time: Again, a very slack evolution with a shallow trough over the southern North Sea so showers or thunderstorms possible in southern and eastern areas. Further into FI and a strong ridge develops NE from the Azores into June keeping the weather fine and warm for most. GFS Control at the same time; Heights to the NE remains strong but the European LP has moved up into southern areas bringing in an enhanced risk of showers or storms. Further into FI and the HP and the continental LP re-orient to bring in a cooler ENE'ly flow with showers still a risk in the south. IN summary, a fine and very warm Bank Holiday weekend for many albeit with a growing risk of showers or storms for the south and south west. Into next week and a range of options on offer - ECM offers retrogression but the percentage call looks to be a slack flow which would be reasonable for most but if you do get a shower or storm it would be very slow moving and consequently could drop a lot of rain on a localised area. Absolutely no sign of Atlantic influence and while Parallel offers a nice continuation of the fine spell into June via an Azores ridge other options maintain the pattern of heights to the north and lower pressure over Europe periodically extending across southern parts of the British Isles.
  2. The 6Z Control has a very strong signal for blocking in low-res. Indeed, the evolution would, if occurring in early January, have this forum in meltdown: A fine example of a retrogressing HP but of course no likelihood of verification. The GEFS, as James suggests and I alluded to earlier, is signalling strong HP for the second May Bank Holiday weekend but the majority of the Members show the HP centred to the north or north east of the British Isles so an E'ly or even NE'ly flow so it's hard to see any temperature records being broken this time and it may be eastern coasts will struggle with sea fog and haar but for most and especially the further west and northwest you are, it looks fine and settled. Let's see how this plays over the next week or so.
  3. Morning all A notch cooler in London this morning but still pleasant enough after the overnight rain. The models were offering two very different evolutions yesterday so let's see where we are today. The medium term analysis takes us to Sunday May 20th and starts as always with the ECM 00Z at T+240: ECM not too different from yesterday. The weekend's disrupting LP fires some energy into Europe re-invigorating the trough over the continent but attempts to build HP back in are pushed south as northern blocking based over Greenland starts pushing the jet back south and the LP systems off the Atlantic start coming on a more southerly track. At T+240 the Azores HP is suppressed far to the south and the LP is moving west to east across Scotland with a second LP set to follow a similar if not slightly more southerly track. It's unsettled with rain or showers for all and quite cool especially in the north. GEM 00Z at the same time: Very different. The blocking over Greenland is much less influential while the Azores HP is much more influential sending a ridge NE to the south of the British Isles. The Atlantic LP is further north and positively tilted so we have a benign SW'ly flow for most with fine conditions for southern and eastern parts though more unsettled in the north west. Signs of the Atlantic trough digging south so we could see a spike of heat from Iberia for the second May Bank Holiday. GFS 00Z OP at the same time: A slow moving and slack evolution which ends up quite messy. As I said yesterday, you have two competing pressure patterns at work. To the west of the British Isles, we have the classic LP to the north west and HP to the south west (though the latter is very shallow on this output). To the east, heights over Scandinavia are balanced by LP over southern Europe originating from North Africa. The British Isles ends up in the col between these competing pressure systems so decent conditions particularly for the south and east but more unsettled further north and west where the Atlantic influence is most noticeable. Further into FI pressure builds through the British Isles from the Azores to Scandinavia keeping most fine but LP remains over Europe and for the south east there would be a light NE'ly and the risk of a shower (more so for the Channel Islands). GFS 00Z Control at T+240: Pretty close to GEM with the Azores ridge holding off the Atlantic LP which is quite vigorous for the time of year. Further into FI HP remains mostly in charge but at the very end of FI, as the HP weakens, the European LP starts to take control with a new LP extending NW across southern Britain suggesting thundery outbreaks. Welcome back to the GFS Parallel run and I'll be featuring this rather than the Control from now on and here's the 00Z at T+240: More of an Atlantic influence with the trough looking to sink SE and join with the trough over Europe. Further into FI it's a see-saw between the troughs to the NW and SE and the HP to the SW and NE. The latter wins out at the very end of FI on this run. The 00Z GEFS at T+240: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=240 As we've seen, the "struggle" between the competing troughs and ridges continues but on this evidence the ridges are coming out on top with a majority of members looking to maintain HP close to or over the British Isles. Moving on toward the second May Bank Holiday and the signal for settled weather is very strong from the 00z. Whether the HP is in the right position or oriented to draw up the warmest air isn't clear but a majority of the members look warm to hot. In summary, May is often a curious month with unusual synoptic patterns and sharp contrasts in temperature and weather. With the Atlantic often at its weakest, the influence of the Scandinavian HP and European trough are often felt more strongly now than at other times. Northern blocking is for the second day running a strong part of the ECM scenario while GEM is more anticyclonic and positive and GFS messy and uncertain. In truth, little change from yesterday. Moving toward the last third of May, the possibility of unsettled conditions affecting the south east in particular from Europe remains but the signal for a dry and settled Bank Holiday has grown this morning and it may be that after the stampede for the sunshine last Monday we may see a repeat performance but it's far too early to be certain.
  4. Afternoon all :) Unfortunately, the daily update running slightly behind schedule but no matter. A cooler but still very pleasant day here in London Town but a sense perhaps of a change back to something more typical for mid May than the current July-like conditions. On to the models and the medium term analysis to Saturday May 19th: ECM 00Z at T+240: http://www.meteociel.fr/modeles/ecmwf/runs/2018050900/ECM1-240.GIF?09-12 On the face of it, not too bad with a ridge of HP covering most of the British Isles. ECM has the weekend LP disrupt and fill over Ireland but the key development is the return of strong northern blocking as a large 1045MB HP sets up over eastern Greenland. The jet is moving back south in the face of this and Atlantic LP systems are going to be moving through the British Isles which means more rain and wind for most. GEM 00Z at the same time: http://modeles.meteociel.fr/modeles/gem/runs/2018050900/gem-0-240.png?00 GEM was the most anticyclonic of the models yesterday but today has come more into line with ECM. After the weekend LP disrupts and fills a new LP develops over Scotland briefly but that too fills in the face of rising pressure from the north and east. As the ridge builds in from the east, the Atlantic LP stalls in situ so a warm and largely settled outlook for most with only the far west of Ireland seeing drizzle. GFS 00Z OP at the same time: http://modeles.meteociel.fr/modeles/gfs/archives/2018050900/gfs-0-240.png?0 A very soggy and unpleasant chart especially for the south with rain, possibly heavy at times, for southern parts. It's quite a messy evolution this morning from the American model and not really in sync with ECM/GEM. After the weekend's LP fills, there's an attempt to raise pressure from the SW but by Tuesday next week a new LP is developing to the NW and squeezing out the heights. Meanwhile, pressure is rising strongly to the far NE and all that does is push the complex trough down across the British isles by the end of the week. Further into FI and the British Isles essentially is in the col between two competing pressure regimes. To the west, we have the traditional LP to the north and HP to the south but to the East we see HP over Scandinavia and LP over Europe so you'd think the Atlantic trough could drop SE through the British Isles or the HP could ridge NE but in essence neither happens. GFS 06Z OP at T+234: http://modeles.meteociel.fr/modeles/gfs/runs/2018050906/gfs-0-234.png?6 Variation on a theme albeit with the small LP about 700 miles further north. Further in to FI and it's a pattern we often see at this time of year as thundery LP heads north from Africa and Iberia toward southern Britain forcing the Azores ridge NE over northern Britain and we end with a warm and dry E'ly albeit with a hint of thunder for the Channel Islands. GEFS 06Z at T+240: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=240 The spread to the NW tells the story between those members who favour a continued Atlantic dominance of our weather and those who look at northern blocking and a more continental influence. The OP went with the latter but the Mean plays the col card which isn't unsupported either. Further on and it's the same old story of the strong signal for northern blocking so we'll see. In conclusion, the pattern through to the weekend and beyond looks set. GFS has quite a messy evolution which doesn't end well for the south while both GEM and especially ECM bring in strong northern blocking which pushes the jet back south. It's far from a washout but with LP systems tending to move across the British Isles rather than to the north we would get quite unsettled and wet spells. There are also hints of low heights from the south coming north which isn't unknown at this time of year and can bring thundery downpours but that's looking more toward the last third of the month and wouldn't be unusual.
  5. Morning all A glorious early summer spell continuing for many into a fourth day with the highest temperature values of near 29c to the west of London. Clear signs of a moderation in temperature this week but into mid month there were, last week, notable hints of renewed northern blocking. This morning's medium term analysis takes us to Friday May 18th and starts as always with ECM 00Z at T+240: It's an interesting evolution. LP approaches from the NW through the coming weekend but disrupts in situ. However, as HP tries to build in from the west, LP over Europe re-asserts and by T+240 a shallow LP centred over western Britain controls the weather so the forecast would be showers or longer spells of rain possibly thundery developing across southern and south western areas in particular. The Azores HP is ridging to the NW of the British isles and the trough remains over continental Europe. GEM 00Z at the same time: GEM keeps the weather fine and settled for many for the foreseeable. The Atlantic incursion over the coming weekend amounts to very little and is pushed back NW allowing the Azores HP to build across the British Isles and by T+240 a large HP cell covers the British Isles with light if not calm winds and plenty of fine weather. A deep LP looks becalmed far out in the Atlantic and all that does is prop up the HP. GFS OP 00Z at T+240: Another very interesting evolution, closer to ECM than GEM in all honesty. The weekend LP tries to disrupt SE through northern parts of the British Isles but a renewed push of heights from the Azores HP keeps southern areas reasonably settled. However, early next week the heights start to recede as LP becomes more organised first to the north and north west before sinking SE through the British Isles and linking with the trough coming north from Africa and southern Europe. The Azores HP ridges more north toward renewed heights over Greenland and to the north of Scandinavia. At T+240 there is a brisk N'ly over western areas but eastern areas are under much lighter winds but with rain or showers developing over the British Isles and especially for eastern parts. Further into FI we get 36-48 hours of unpleasant cool and wet conditions from a small LP in the southern North Sea before the trough transfers NW back into the Atlantic and heights build in again from the SW. GFS Control 00Z at T+240: Cool and unsettled with the LP sinking south toward the British Isles. Further into FI the trough remains close to the south and east while heights build to the north and west leaving winds in the easterly quadrant and a greater risk of rain or showers for southern and eastern areas. The 00Z GEFS at T+240: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=240 Two main clusters on offer - one has the Azores HP building strongly in from the SW and the other doesn't meaning LP over or close to the British Isles so, if you like, the GEM evolution versus the ECM solution. Further into FI and the signal for northern blocking remains with only two or three members keeping the Atlantic as the dominant force. The northern blocking varies in position and orientation considerably. In summary, two possible evolutions into medium term this morning. The GEM evolution keeps the weather settled with the Azores HP ridge taking over once the weekend's Atlantic incursion disrupts and retreats NW. The ECM/GFS OP solution is messier and brings low heights over Europe into play with enough energy phasing from the disrupting Atlantic trough to invigorate the trough over Europe which spreads north. The question then is one of energy transfer - with GEM there is no transfer of energy and the anticyclonic ridge builds back through the British Isles but with ECM and GFS enough energy spills SE across the British Isles to re-invigorate the European trough and send it north. Which model is correct or are both wrong ? As ever, more runs are needed.
  6. Morning all With a decent weekend heaving into view, how are we looking as the weekend after that approaches ? When I last looked a couple of days ago, there were plenty of hints the anticyclonic spell might break down to something more unsettled so let's move ahead to Sunday May 13th starting as always with the ECM 00Z at T+240: A decent evolution for many from ECM with the weekend's cell of HP easing east to be replaced by another midweek which in turn moves over Scandinavia. The T+240 char tis a little messy but with the jet held well to the north you'd think settled conditions would dominate especially for southern and central parts. A shallow area of LP to the west of Scotland doesn't look to be doing anything much at this time with the large Azores HP dominating to the west. Over Europe low heights have been pushed well to the south and south east. GEM 00Z at the same time: A much more unsettled evolution from a model which has previously played the anticyclonic card very strongly. The weekend HP eases to the east by Wednesday but there is no second cell as per ECM. Instead, a much more active Atlantic brings LP and frontal systems toward the British Isles. The feature to the north of Scotland is in fact a secondary LP which swung NE across Ireland being gales and heavy rain to western parts. The forecast would be rain or showers for all with the heaviest rain in the north. Hint of a brief ridge coming through before further LP systems move in off the Atlantic. GFS 00Z OP at the same time: Again, more unsettled. As per GEM, an active LP sweeps in from the Atlantic passing to the NW of Scotland and by T+240 is easing away NE with a residual trough over northern parts while there are signs of pressure rising further south. Further into FI and an unusual evolution as LP develops over central Europe and moves WNW across the British Isles so a potentially cool and quite wet spell of weather around mid month. GFS 00Z Control at the same time: The evolution in Control is similar to the OP if a shade more progressive. The deep LP moves away more quickly to the north and fills leaving a small trough over northern parts. Another curious evolution further into FI - pressure rises over Scandinavia and falls over Europe and a small but active LP moves west across southern Britain leaving all parts in a warm SE'ly. The GEFS at T+240: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=240 The Mean suggests encroaching LP from the NW and there are only a couple of GFS members with anything like an ECM evolution so suggests that may be a shade of an outlier. Most have LP passing to the north of the British Isles but two or three hint at disruption SE across the British Isles and into Europe so possibly one to watch. Further on and there's plenty of northern blocking but we've seen it before in high-res and it rarely comes through to low-res so at this stage I'd say the signal past mid-month is there is no strong signal at this time. In summary, a fine spell through this weekend and into the middle of last week looks unlikely to continue much further. ECM tries to continue it but looks isolated as both GEM and GFS bring in more unsettled conditions off the Atlantic. GFS explores some synoptically unusual solutions further into FI but that's a long way off.
  7. Morning all After yesterday's winter-like day in lowland East London, we start a new month with a considerable improvement - the Sun out and the temperatures on the up. The weekend ahead looks set fair which will please many but where do we go from there ? Plenty of possibilities yesterday and let's move to the end of next week, Friday May 11th, for this morning's medium term model analysis Starting as always with the ECM 00Z OP for T+240: Reminiscent of yesterday's 00Z GFS OP - the first HP for the weekend declines but new heights build to the north and north east of the British isles so by T+240 it's generally settled but with a cool NE'ly breeze across southern parts. The next LP is negatively tilted and it would be fascinating to see if it would dive SE to the west of Ireland (as GFS OP did yesterday).. On then to GEM 00Z at the same time: GEM was very anticyclonic yesterday and remains so today but as yesterday a hint of change at the end of the run and as yesterday it's worth looking south as the trough develops over France and, combined with falling heights to the west, my view would be the warm settled outlook would degrade to showers and something much less settled. Let's see if the trend continues through tomorrow. GFS 00Z OP at T+240: An increasingly unsettled outlook as LP has moved down from the west of Iceland to be just off North West Scotland with frontal bands crossing the country albeit with only light rain for the south east. Further into FI and the unsettled picture continues with LP close to the north-west of much of the run. GFS 00Z Control at the same time: Not a million miles from the OP but with a more intense LP close to western Britain so rain and strong winds for Ireland. Further into FI and the LP disrupts to the north west as heights build again to the north as was a feature of 00Z low-res yesterday. The 00Z GEFS at T+240: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=240 While the OP and Control scenarios aren't without support in the suite the majority call is to retain the anticyclonic domination with HP close to or to the north east of the British Isles more aligned to the ECM solution. Further into FI and the strong signal for northern blocking remains undiminished with HP close to or to the north of the British Isles across the ensemble members. In summary, fine weather for the Bank Holiday and continuing through next week on the models but a hint of a change at the end of next week with LP encroaching from the NW or south and heights falling to the west suggesting a more thundery and wet outlook for many. This looks short-lived for the north with HP returning by mid month but the south remains potentially warm and unsettled with the risk of thundery showers or rain. Today's bonus chart comes from T+5736: Fine and frosty for the British Isles with, as usual, the coldest air just missing us and a white Christmas for the south of France.
  8. Morning all A pretty disappointing start to the week here in lowland East London with rain and a cold wind but change is the only constant when it comes to our weather and it's looked likely for some time the first May Bank Holiday Weekend will be decent but what happens from there. Today the medium term analysis takes us to Thursday May 10th and starts with the ECM 00Z at T+240: The fine spell over the BH weekend breaks down next week as the HP declines far enough east to open the door to the trough and more than a hint from this chart that the LP could slip SE into Europe and change things considerably. For now, a gradual cooling with rain or showers encroaching from the north west. GEM 00Z at the same time: Anticyclonic and settled would be my take on the GEM run this morning. The HP for the Bank Holiday weekend is easing away but the ridge from the Azores id heading NE through Ireland and western Scotland so a continuation of decent weather. Note the shallow LP to the south however which brings a risk of showers to extreme southern areas but most places will be fine and dry. GFS 00Z OP at T+240: Another evolution from GFS. The HP keeps well to the north and the LP becomes a cut-off feature well to the west of the British Isles so for most the weather remains warm and settled but with a growing risk of rain or showers for south western parts. Note also the profile around Greenland which in contrast to ECM and GEM and shows heights and warmer air. Further into FI and heights remain strong to the north throughout with winds mainly from the east. GFS 00Z Control at T+240: Very different again. Weaker heights to the NE and the trough coming SE into Ireland and western Britain so a much more unsettled prospect. Further into FI and the LP initially is close to southern Britain before retreating slightly SW and at far FI the OP and Control are actually quite close in terms of evolution with Control setting up an easterly pattern. The 00Z GEFS at T+240: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=240 The key message to my eye is HP is close to or just to the north or north east of the British Isles but little sign of a strongly Atlantic pattern with only two or three Members suggesting it by this time. Further into FI and there's a surprising lack of spread suggesting a strong signal for northern blocking for the middle of the month and beyond. In summary, after the forthcoming fine weekend plenty of disagreement over future developments. ECM and GFS suggest a breakdown from the NW with the trough dropping close to (GFS Control, ECM OP) or to the west of the British Isles (GFS OP) with only GEM OP keeping the weather relatively settled though with hints of problems for the south and indeed further into FI the signal of heights to the south with pressure lower over the south and south west seems to be quite noticeable as we move into the middle of the month and beyond but we often see this in low-res and it doesn't translate as we come into high-res. Anyway, some pleasant days in the near future to enjoy.
  9. Here in lowland East London we've had a fair bit of rain so far. At the moment it's light and intermittent but we've had some heavier bursts especially earlier this morning. The rain band is moving slowly westwards but the heaviest rain is currently well to the south over the Channel and northern France. It may be the small LP is just taking its time before it moves NE and starts pulling the rain band more north west and back over the London area. It looks in for the day with a clearance just in time for sunset.
  10. Morning all It doe seem as though some may get a final taste of winter later this weekend and into Monday which looks a particularly cold and unpleasant day for many but it's May (nearly) so in the battle between the warmer and colder air masses which has characterised the past two or three months the warmer side is getting the upper hand but it's been a real spring of contrasts which can be blamed on the weaker influence of the Atlantic. Moving on and looking at where we might be on Bank Holiday Monday, May 7th, and starting as always with the ECM 00Z at T+240: It all ends perfectly well for fans of warm settled conditions but the start of the week won't be pleasant with a couple of unpleasant cool wet days. As the LP moves off and fills, the Azores ridge builds through the south midweek and then transfers to the east setting up as a new HP cell over the southern Baltic leaving the British Isles in a warm ESE'ly wind for the Bank Holiday Monday. GEM 00Z at the same time: A very similar evolution in broad terms to the ECM. The HP ends up over Scandinavia with the ridge aligned SW back across the British Isles and a light NE'ly but still very pleasant. The critical moment is on Tuesday when the LP looks to dive SE across the British Isles but the ridge from the Azores gets there first. GFS 00Z OP at T+240: Something slightly different from GFS. The overall evolution is initially similar but as the HP transfers across the British Isles it declines and the core of heights never develops as a new cell over Scandinavia but is a ridge to a core much further north. In addition, the LP over the Continent is more pronounced and much closer so it's an E'ly flow but with a risk of showers for southern and south eastern parts. Further into FI heights remain to the north with LP to the south so it's variations on a mainly E'ly flow but quite a messy evolution. GFS 00Z Control at T+240: Very similar to yesterday with the Atlantic very much in charge and a fresh W'ly wind over the British Isles. Further into FI and the flow becomes more amplified ending with a developing LP over Europe and an E'ly for southern parts. So, two very contrasting GFS evolutions at T+240 so let's look at the GEFS: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=240 I'd say the emphasis is on an anticyclonic evolution but where the HP sits and how it is oriented is far from clear. I see more support for an OP type set up than the strongly Atlantic evolution favoured by the Control (though that has some support as well). The Mean suggests HP to the SW and that's well advertised. Further into FI we get our usual signal of heights to the NW but no strong trend as we move into the middle of the month apart from the obvious of no warm southerlies or cold northerlies. In conclusion, the evolution for the next week or so looks fairly well defined, After an unpleasant 48 hours or so especially through Monday, the ridge builds back from the SW drying and warming the weather through midweek. From there GEM and ECM build the HP over Scandinavia ushering in a new period of warmth but GFS is less convinced and the threat of showers from Europe remains or the whole pack of cards collapses as the Atlantic returns. The GFS OP this morning intrigues with further strong northern blocking as we move into May (not atypical) so we'll see where that goes after the weekend.
  11. Morning all A huge contrast from today to this time last week when we were heading toward 29c in London. - currently 14c and raining. Anyway, before the Mods remind me how off topic I am, back to the models and the medium term analysis taking us to Sunday May 6th and the middle if the first May Bank Holiday Weekend. Starting as always with ECM 00Z OP at T+240: The ECM OP run isn't that bad if you like warm, settled conditions but it requires going through a week of more unpleasant conditions. Essentially, LP develops to the south over the coming weekend and into early next week bringing a brief spell of cold and wet conditions before the ridge builds in from the south west and settles the weather down before drifting east to sit as a large cell over the North Sea and Southern Scandinavia with a slack ESE'ly over southern parts. GEM 00Z OP at T=240: A curious offering this morning. A large and strong HP develops to the north of Scandinavia and moves south instigating a strong ESE'ly over southern Scandinavia and a weak trough in the southern North Sea. At the same time, the Azores HP organises and ridges NE so by T+240 it's all very anticyclonic, fine and settled. GFS 00Z OP at T+240: Another evolution but again it all ends very settled for southern and eastern parts of the British Isles with a long ridge of HP from the Azores. The Icelandic LP meanders around but with a positive tilt so the north and especially far north west will always be prone to rain and drizzle. Further into FI, with pressure building to the NE, the door is opened for the trough to push through or just to the north of the British isles so more average conditions moving into the middle of the month. GFS 00Z Control at T+240: All very average. Less settled than the OP with LP more in evidence to the north and a new LP swinging in off the Atlantic. Further into FI, it gets almost autumnal in aspect with some vigorous LP systems about and plenty of rain and strong winds for all. GFS 06Z OP at T+234: Less settled than the 00Z OP and tending more toward the 00Z Control with the HP looking to be squeezed out by encroaching Atlantic LP. Further into FI and there's a brief and quite unsettled spell before HP builds in again from the SW. There's a clear divergence once again between GEM/ECM and GFS. The former is more strongly anticyclonic keeping a signal for northern blocking and generally keeping the Atlantic at bay. GFS is quite different with the Atlantic becoming more dominant again (and potentially quite autumnal) before a return to more settled conditions by mid month. NO sign of cold northerlies or warm southerlies at this time - the pattern looks quite mobile. In summary, despite one or two signs from GFS, fans of warm, settled weather should take heart from the morning's output. There will be a week or so of poor conditions to get through but as we go further into May the signal for something settled has gained strength. It's more likely to come from the SW than the East so perhaps warm rather than hot at this time but nonetheless perfectly reasonable. Finally, for a bit of diversion, here's a nice wintry chart for Christmas Eve, a mere 5,820 hours away !!
  12. To add to the above, the GEFS 06Z at T+240: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=240 To this observer, the OP looks a little isolated but the Control looks more reasonable. It's a mixed bag and while some members bring in the ridge from the SW, the majority have LP close to or just to the south of the British Isles. In far FI, the 06Z GEFS keeps a strong signal for blocking from the NW or NE but as that so often fails to last into high-res I'd be very cautious at this time.
  13. Morning all The post-early summer blues seem to have set in with a vengeance but it was always probable in a year like this with a moribund Atlantic and an SSW that we would be contrasts between the warmer and colder air masses and, to be blunt, it's still April. Snow in May on higher ground in Scotland isn't unusual and frosts even in the south far from a rarity. The journey goes on and so must the medium term analysis which this morning takes us to Friday May 4th and as always kicking off with the ECM 00Z at T+240: ECM this morning has backed away from its own 00Z solution of yesterday to the GFS solution from yesterday which has the LP moving SE from Iceland toward the British Isles. GFS had the LP passing to the west of Ireland but ECM looks like bringing the LP down over the British Isles so the promise of a poor first May Bank Holiday. The Azores HP is too far away to be of any value. Increasingly unsettled and cool conditions for most with rain or showers especially for northern and western parts. GEM 00Z at T+240: A completely different evolution and more in keeping with the GEM of yesterday morning. The trough coming from the NW is held at bay by a ridge from the Azores at the critical point of T+180. The LP fills in situ to the north and the next LP from the Atlantic comes on a positive alignment allowing heights to build from the SW and by T+240 we have a new HP centred over Denmark and the southern North Sea with a light ESE'ly flow bringing fair and warm weather for most with only the far north west of Scotland bothered by Atlantic drizzle. GFS 00Z OP at T+240: Better than yesterday which wouldn't be difficult. LP over central Europe but meandering east allowing the ridge to come up from the SW and link with emerging heights over Scandinavia so a decent outlook with a light NE'ly over the south cooling things down but fine for most. Further into FI it remains fairly settled with HP never far away from the south west so southern and western areas generally settled. Always a threat of rain for more northern and eastern parts - cooler too with occasional NW winds. GFS Control 00Z at T+240: A cool and showery (especially for the north) WSW'ly flow with a ridge to the south of the British Isles into Europe but LP close to Iceland. Control, like the OP, keeps the onus on more settled conditions with increasingly influential (and large) Azores HP extending the ridge NE so decent conditions for early May for many. By way of contrast, here's the GFS 06Z OP at T+234: Very different with a cool NE'ly over the British Isles and a deep LP over central Europe though what we have is NOT the LP that comes through the British Isles but a separate LP moving up from Africa which is invigorated over the Med and by our LP and becomes an active system for an inland depression.
  14. Indeed GEM looks poor through next weekend and even into Monday but it gets the LP out of the way quickly to the NE leaving a col before the HP ridge builds in. ECM takes the LP just to the east so a poor second half of the weekend for southern and eastern parts before the LP shifts NE and the HP can build in so late Monday into Tuesday is the key moment. As for GFS 00Z OP, the LP doesn't clear away cleanly, part of the energy goes south, part hangs over the British Isles so the negatively aligned trough comes into the space and the HP is shut out. That's the pivotal point of the evolution but the GFS is following the pattern from later this week of having the trough drop through the British Isles from the NW and become absorbed in the LP to the south re-invigorating the LP and controlling the pattern through the weekend. Whether the GFS is simply seeing the repetition of the pattern while the other models are trying to break out of the pattern (by a default reset to an Atlantic-dominated westerly pattern) I don't know. The GFS OP is following what we saw a lot through the winter with negatively aligned troughs sliding SE rather than following the conventional west to east movement - a product of an amplified or weakened jet stream ?
  15. Morning all Last week's exceptional spell of warmth is already fading into memory. Much cooler and cloudier in London this morning after five days in the 20s and a couple above 25c. The problem is in a year with an SSW and a moribund Atlantic the extremes of warm and cool which are usually tempered by the Atlantic and the average westerlies, are able to come forward with air flows from the SE or indeed NE more common with the resulting contrast in temperature between air masses. So will the beginning of April see fridge or furnace, bbq or hot bevvy ? Today I'm looking ahead to Thursday May 3rd and starting as always with the ECM 00Z at T+240: In the end, a decent chart with a long ridge of HP from the Azores covering most of the British Isles bringing increasingly settled conditions but the journey to this chart isn't pleasant with plenty of LP close to or over the British Isles in the next week. GEM 00Z at the same time: Not too far removed from the ECM though with a deeper Atlantic LP and a more displaced Azores HP but still a ridge over the British Isles allowing things to dry out after what looks a very unsettled and wet weekend ahead with LP to the south of the British Isles moving north over England. GFS 00Z OP at the same time: A very different evolution and it starts with the trough becoming negatively aligned rather than the positive alignment with GEM and ECM which allows the ridge to be thrown forward from the SW. With GFS the LP forms to the west of Iceland and swings SE to the west of the British Isles as HP builds in mid Atlantic behind it. At T+240 the LP is to the west of Ireland with a light SW'ly over much of the British Isles but rain or showers likely especially for western and south western areas. Further into FI, the trough elongates across southern parts before the core LP moves eastward then SE to northern France leaving most parts in an easterly flow with improving conditions for northern and north-western parts. GFS 00Z Control at T+240: On the Control, the ridge "beats" the trough so before the LP can slide SE, the Azores HP is ridged across the British Isles so a drier and warmer evolution with most areas beyond the far north dry. Further into FI and the large Azores HP remains in charge but its position and orientation doesn't allow for the advection of warm air from the south - instead, the flow is mainly west or north-west so settled but only average temperatures for most. The GEFS at T+240: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=240 A real mixed bag with as much spread as I've seen for several days but essentially we've two scenarios (or variations) in play. One brings the trough down over the British Isles with ridging to the NW behind it and the other gets the ridge over us first and keeps the LP systems to the north of the British Isles. Glancing further into May and the signal for heights to the north remains evident with the OP solution having more support than the Control at this time. In summary, a much cooler and progressively more unsettled week ahead culminating in what looks a potential washout for southern parts over the coming weekend as the LP to the south develops and moves across southern Britain. From there, two scenarios come into place - GEM, ECM and GFS Control keep the LP to the north and bring a ridge back across the British isles from the south west but GFS OP has a more negatively tilted trough which comes SE with the mid-Atlantic ridge building behind and ushering in a period of renewed easterlies with LP setting up over Europe. I imagine many in here will want the former for obvious reasons but the latter isn't without support on the GFS suite and the signal for northern heights further into May remains strong as we move further into the new month. Let's see where this journey takes us...
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