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Showing content with the highest reputation since 09/08/18 in all areas

  1. 27 points
    Scattergun ensembles do not mean this, as expressed in a typically over dramatized and extrapolated ahead context as given here Which leads on appropriately to a rather more objective, helpful and considered post: I think your analysis sums up well why there is no reason to over dramatize or extrapolate ahead the present pattern for the whole of this month. An examination of latest EC clusters play with the continuing theme of Atlantic trough and downstream ridge and the truth is there are only modest adjustments required in the solutions that dig the trough further south to put a subtly different complexion on the pattern. This does, its true, mainly apply further south at least to begin with but ramifications over wider distance still apply and have support. Mindful of the fact that the GWO has quickly returned to Phase 4 after a full orbit previously into Nino Phase 5 in late July …. . ….as reflection of how angular momentum is embarking on a long term trend to different territory than the previous two years, then its a matter for the tropical signal to add that small extra bit of extra downstream amplification to accentuate the trough/ ridge pattern and adjust the ensemble suite pendulum onto further support for the greater warmer advection solutions that already exist and reflect the readiness of the anomalous warmth that remains very close to our shores throughout this more changeable spell to spread back across the channel. The degrees of adjustment here are really quite small to make subtle but quite real differences within how the macro pattern affects the micro UK pattern. A good example of why this type of non numerical modelling diagnostic approach is a macro scale guide and not intended to try to second guess detail at distances which is always highly unwise anyway when NWP itself has a spread of solutions within a same theme. Hence just one real expression and interpretation of ensembles that are scattergun - but better explained than simply taking one solution as influential for weeks ahead for the sake of the pessimism attached to it, or just simply plucked out of the air for the pessimistic gut feeling associated with it. Even as it stands, taking a look at the graphical spread of solutions from the EC 0z, these are not exactly a terrible spread of London ensembles for what is the least underwhelming passage of weather in a summer that has been truly remarkable for its absence of anything like it, Yes, it is London representative for the UK which looks set to see regional varieties abound in the coming days, but it does look like the operational, even within its own cluster may be rather too aggressive with the greatest influence of the trough later next week. And that suggestion also allows for the temperature gradient issue correctly pointed out. Usual caveats anyway here with ensemble suites exists - based on them being merely snapshots in time. The "worst" solutions here are also evident within the GEFS suite, and which take the upper trough furthest east - are based on the very lowest angular momentum side of the envelope which has the tropical signal furthest west. Much as discussed recently. Even if this did happen, it would simply be a delay to recovery and hence why some professionals will rightly currently be hedging bets in terms of their extended forecasts. The effect of any suggestion of delay in some quarters on this forum however, seems to take on more magnitude than reality - simply because we are coming close to the final two weeks of official summer and some kind of irrational "time is running out" extravagancy takes over But the weather does not eschew the enchanting human habits of a weather forum that has self imposed cut-off dates - and if it wants to, then September as in reality we know, may quite easily be a further extension of what has largely preceded it in overall weather type this summer. Much as last September, in contrast, ushered in an earlier feel to autumn than accustomed to in recent years. The Global Wind Oscillation will be the best guide here to gauge the progress of the tropical signal and the subsequent impacts on jet stream wind-flow in the extra topics. Based on its current evolution and associated AAM parity, and based on likely future tropical>extra tropical evolution, that continues, until of if any evidence to the contrary appears, to suggest that some model correction to some of these coolest and most unsettled solutions lasting longest - will see them outed as the more counter intuitive. That doesn't mean the current changeable spell isn't supported within the 10 day period, but it does mean that distinct regional variations may well occur within this time and it also means any extrapolative negatively worded suggestions out to the end of the month (and even beyond) do not, at this time, have any justification - beyond taking opportunity of some less favourable weather to over agitate the closer perspective... -and of course the thread itself.
  2. 15 points
    Oh and for what it's worth, this will be added to the guidelines shortly..
  3. 12 points
    Further to Tamara's excellent roundup of the situation: Another shift today toward a phase 5 MJO re-emergence, and there are now some EPS members which only take about a week to reach that point, even as others continue to be quite a way off from there a whole fortnight from now. That really highlights the huge uncertainty - no wonder the EPS clusters offer a wide variety of trough/ridge placements. Some amplification to the flow is a common theme flow, reflecting the Nino base state sending AAM upward from the current phase 4 GWO position. The theoretical 'lean' is toward those members reaching phase 5 within 7-10 days from now. With AAM likely rising before then, a ridge across S UK still seems a plausible outcome for next weekend. Hopefully the 12z runs will add confidence to this (...now I've gone and done it! ha).
  4. 11 points
    Not been about much as been on hol's in Europe and doing some lurking! Love from Croydon...(actually Titsey Hill, but close enough). Only a little storm and i was a bit late but got a few.... )
  5. 10 points
    The more eastern main Atlantic trough solutions continue to seem more suspect to me than the more western ones, based on the models moving the tropical setup further away from the Nino configuration than seems reasonable. Ex-Bertha adds uncertainty in that it may interact with the main Atlantic trough in a way that brings about a 'trail' of lower SLP down near the Azores, displacing high pressure across us by late next week in the manner of the GFS 06z, but equally, it could remain independent of the Atlantic trough, allowing that feature to be much flatter in shape. Even in that flatter scenario, though, I'd be surprised to see the main trough move as far east as the ECM 00z takes it. I'm of the impression that we'll have a fair bit of tropical maritime air coming our way next week, but with LP close enough by to wring some spells of rain out of that, particularly in the northwest where it could be very wet overall. Mild to very mild nights, but away from the south, near to below average daytime highs keeping indoor temperatures comfortable for those who don't like it hot. Then for the final third of the month, we move into 'Nino-forcing proper', with a good chance of exchanging westerlies for a continental flow (for more than just the odd day). Models still need to adapt their tropical outlooks a bit for that to start being represented better.
  6. 9 points
    The models really don't have much of a light to guide them for next week. I can understand why they're so hesitant to kick off the MJO in the Pacific rather than west of there; the SSTs anomalies in the C and E Pac are mostly within a few tenths *C of zero, meaning a lot of the expectation is down to the tropical-extratropical interactions taking place, which the models have a harder time handling. It also makes it harder for us humans to anticipate how fast or not things will progress. I think the GFS 00z and ECM 00z captured the soonest and latest 'reasonable' limits, though, in terms of how soon we start to see high pressure gaining more influence from the southwest. I'm not convinced by how far east they're taking the Atlantic trough mid-late next week, as the jet stream is being modelled to be unusually strong for a non-Nina base state, but I can see how it could be a result of the Atlantic SST anomaly pattern which has a lot of negatives northwest of positives, enhancing the temp gradient that the jet stream has to work with. However, as long as the main trough moves north of east, we can still get the pressure rise from the southwest (GFS 06z getting all mixed-up at this stage; one for the bin). No denying this is an irritating time if you were hoping for the 'lull' in Nino tropical cycles to be brief with a quick resumption of anomalously warm conditions. Back in late July, that was my anticipation, but that was based on the tropical Pacific SSTs widely reaching the +0.5*C mark by around now. This should kick those anomalies up a bit in the C Pacific, but the fact we're waiting until almost mid-month for it is among the main reasons for this unfortunately lengthy 'lull'. Sure, it still may turn out not too bad in the south, but I'm sparing thoughts for those up north who have had the cooler, changeable/unsettled weather for longer already, and look to be in the thick of it next week as well.
  7. 9 points
    Distinctly chilly here at just 10C. Looks like convection is off to a good start though, could be a fun day for storm lovers. A mate flew in to Heathrow this morning and sent me a couple of snaps from the air. Nice line of Cb’s
  8. 9 points
    Quite a lively thunderstorm just passed through here near Croydon in south London, thunder and lightning getting more frequent as it pulls away east, this the scene to the west before it arrived
  9. 9 points
    Loading grain this morning 24 hours after cutting it. Quality is not good and would not be accepted in a normal year but in a year with a worldwide severe shortage of grain every grain is needed. Yields are down a bit but prices are going up every day on the grain futures markets so that will help.. So after getting a text telling me the bad results the frown of PHT ( pre harvest tension) has disappeared to be replaced with a smile as the quality goalposts were moved. Note the brown grass. Fresher today with a maximum of 16c
  10. 9 points
    We'll be getting into what I call the Dog Days soon. Traditionally the dog days of summer are when the dog star, or Sirius, is visible in the sky, and coincided with the hottest, most sultry days of the summer. I believe farmers may refer to it a lot, I'm not sure. However, my idea of the dog days are those late days of summer, where you began to sense the season was on the wane. The last of the heat was still in the sun, and you can still get some nice weather, but the novelty of glorious sunny days has begun to wear off (as if it ever could in Scotland!), the school holidays have ended - meaning delight for some, but I associated it with the foreboding of my youth of having to return to class. It's like nature is saying the fun is over soon, and you feel like you're just waiting for autumn to make it's first appearance. Obviously a bit early for autumn talk, and there should hopefully be a good month or so of mainly decent enough weather to go, but just thought I'd make a post about what this time of year means to be and the associations that it brings in my head. In some ways I find it quite pleasant, giving the chance to make the most of the remaining light nights, and in better summers such as this, you hope that they will never end.
  11. 8 points
    Just got sent this image from my cousin in london What is it, a shelf or a wall cloud?
  12. 8 points
    Storm & Convective Forecast Issued 2018-08-10 07:33:55 Valid: 10/08/2018 00z - 11/08/2018 00z THUNDERSTORM OUTLOOK - FRIDAY 10TH AUG 2018 Synopsis Upper trough extends south across NE Atlantic and British Isles on Friday morning and will edge east to be across the North Sea / Norwegian Sea by late evening, further east upper ridge extends NE from SE Europe into western Russia. A cyclonic westerly surface flow will cover the UK, unstable to surface heating. ... ENGLAND, WALES and S SCOTLAND ... An unseasonably deep and cold upper trough will cross the UK today, with 500mb temps as low as -25C, these cold mid-level temperatures atop a moist surface airmass heated in sunny spells will create steep lapse rates. Instability will be greatest this morning across the west before subsiding here into the afternoon when CAPE increases across central, southern and eastern England this afternoon, 400-800 j/kg range during peak heating. The passage of the upper trough will create large scale ascent beneath and ahead of it, before heights rise across the west in its wake this afternoon. So heavy showers and isolated thunderstorms are likely from the word go this morning across southern Scotland, NW England, Wales and SW England, before heavy showers and scattered thunderstorms develop further east across England through the day, as the upper trough advances east and surface heating increases instability. W/NWly jet streak punching east across southern Britain will yield 0-6km shear values in the range of 40 knots - the strong upper winds and modest vertical shear will favour organisation of showers and storms into line segments across south Wales and SW England this morning, then central-S and SE England along with East Anglia into the afternoon. Mid-level dry air intrusion accompanying the jet streak will enhance convection, with some strong storms possible, the dry air also increasing potential for strong winds aloft to lower to the surface - bringing the risk of isolated strong wind gusts. Also hail may accompany storms, with potential for hail stones of 1-2cm in stronger cells, there is also potential for localised flash-flooding. Some backing of surface winds is noted on recent obs across SW England before winds switch westerly, indicative of trough passage, which suggests some strong low-level shear potential which may enhance the risk of stronger updrafts rotating into storms, so can't rule out a brief tornado too across S England. Further north across England and southern Scotland - showers and storms will become increasingly confined towards the east in the afternoon, as heights rise to the west and convection weakens across Wales, N. Ireland and NW England, any showers and storms towards the east will still have the potential to produce hail, gusty winds and localised flooding. https://www.netweather.tv/weather-forecasts/uk/convective
  13. 8 points
    A few screen grabs from iPhone video of storm as it cleared east of Croydon, unfortunately the DSLR wasn’t charged up this evening
  14. 8 points
    Just going through photos from Essex the other week and something struck me - it’ll be a while before we get scenes like this again - the yellow grass against the deep dark grey/blue skies - amazing to see: Edit: ok it might have been wheat here - but in other pics it was defo yellow grass
  15. 8 points
  16. 7 points
    GFS is acting like an excited puppy; sure it makes a mess sometimes, but it keeps trying to find ways to please you in between. UKMO the older, more restrained dog but willing to entertain the puppy's ideas at least a little bit...
  17. 7 points
    That’s great. like you I love hot weather, just not the oppressive heat we’ve had recently. If everyone liked the same thing this forum would be boring
  18. 6 points
    Really? Some are never satisfied. This has been the best summer we've had for many a decade, yet still people have cause to grumble. Depressing my weeble. Two wet days in months, ha ha.
  19. 6 points
    Very interesting convective skies this afternoon, not seen this for a while. Bit cool out, just 18C currently with a very blustery SW’ly blowing.
  20. 6 points
  21. 6 points
    Thunder and lightning to the north east of Dorking and this to the west
  22. 6 points
    A gorgeous day here with sunny ints and a high of 19.6C. Currently some light showers around giving great rainbows in the sunshine. Pictures didn’t really capture this double rainbow with all colours clear in the main bow.
  23. 6 points
    Been the sunniest June and July period on record and then add in May as well. Truely exceptional.
  24. 6 points
    Important not to get weather and climate mixed up. I'd not consider an isolated one or two exceptional months to mean much, but here for example, my location has seen top 5% mean temperature months for each of April, May and June, followed by a record-hot July. That's beyond what can be reasonably explained by natural variability. Cold months, even record cold ones, will remain possible so long as snow falls across northern Asia and Scandinavia Nov-Mar, which thanks to the polar night, should always be the case. In fact, snowfall is likely to become deeper in those regions as a result of increased moisture availability from the warmer oceans. This could even lead to 3+ consecutive exceptionally cold winter/spring months one year soon... the warming global climate necessarily mean that the UK will share in that trend all year round.
  25. 5 points
    Was a surprise to see a storm pass directly over me for a change, was some very strong winds in the core with poplar tree in our back garden getting bent horizontal in top half at one point, the lightning really ramped up as it clears, was videoing it so hopefully will get some stills of lightning in a bit. I thought it maybe a long shot forecasting earlier today a storm risk in the southeast today, paid off though https://www.netweather.tv/weather-forecasts/uk/convective
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