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Showing content with the highest reputation on 04/07/16 in all areas

  1. 9 points
    June has been an interesting month for many parts fo Western Europe, featuring excessive rainfall and floods for several parts of e.g. Germany, Switzerland and the Netherlands. This was caused by relative weak pressure differences over mainland Europe, on average rather low pressure and relatively moist air. However, July has shown a turnaround in the pattern. A steady westerly flow has brought a series of troughs and low pressure areas towards Europe, resulting in mostly changeable weather. Will this westerly flow persist, or will we see a significant change in the weather patterns to come? Westerly flow - but ridge to come The westerly flow has also been dominating today with low pressure to the north of the UK and high pressure to the south. However, change is on the way if we look upstream - just south of Greenland. GFS analysis of 500 hPa heights (colours) and surface pressure (white contours) for Sunday 12Z. To the south of Greenland, a weak ridge can be identified mainly in the upper levels (orange colours pointing northward). Often such high pressure areas (or ridges) tend to stabilize the weather for some time. - But for how long? The ridge will pass by the UK around this Wednesday, but it does not seem to be a rather transient feature. This fits very well in the pattern which we have observed over the past week or so - with ridges and troughs quickly alternating in a meandering westerly flow. GFS forecast of 500 hPa heights (colours) and surface pressure (white contours) for Wednesday 12Z. From the west a new low pressure area (green colours) is again approaching the UK. But will it also reach the UK? The models agree that this will somewhere around the weekend. However, one can also see notable differences developing between these models on the details of the low pressure area. (Un)certainty and phase differences The further outlook is what one could call certain as well as uncertain - depending on the point of view. Although there is a lot that can be said about the general pattern - it is about nigh impossible to have a certain local forecast in 6 days out or more! And we can caputure this (un)certainty in just one plot. GFS ensemble spaghetti forecast of 500 hPa height for Monday (8 days out) 12Z. The image above shows an ensemble of GFS forecasts for 8 days out. Here one should focus on the bottom lines, indicating the height of the so-called 5760 dam (5.76 km height) surface. Each line represents one model run. First of all, it can be seen that all lines are generally very close together for the 576 dam line, suggesting high certainty in the overall forecast. This forecast suggests low pressure to the north and high pressure to the south, with a potent westerly flow in between. One can also see this from all lines running west-east. See also the forecast of the CPC (Climate prediction center) for day 6-10. However, there is one huge caveat if one wants to apply this to a local weather forecast. If you examine all the lines individually, you can see that there are slight meanders in them. The position of these weak meanders (which can be interpreted as ridges if they point northward and troughs if they point southward) varies from run to run. However, the exact position of such a small scale feature is very important for the weather on that day. For example, a ridge for a given day (a northward pointing line) would argue for settled conditions, and a downward-pointing line would suggest a trough and thereby unsettled conditions. This uncertainty is what one could call phase differences, as depicted in the figure below. Illustration of phase differences between various model runs. Note how the location of the ridges (H) and troughs (L) differ strongly, an indication of a phase difference. Summary It appears that the westerly flow which has been present over the past few days will continue to persist for at least the next week (and probably thereafter). This will create changeable weather (with a possible drier interlude on tuesday-friday). Details at long range are hard to gauge due to the phase differences discussed above, but it is pretty certain that the main theme will be changeable weather.
  2. 2 points
    I'm not allowed to post much these days (work permits little), but I just wanted to point out that the 500mb anomaly charts are misleading for this week due to the fact that we have an unusually weak ridge of high pressure, which gives negative height anomalies in our vicinity yet still manages to prevent an unsettled regime across England until Fri or Sat. I'll leave you all to it now, have a good week
  3. 2 points
    The ecm and NOAA still in the same ball park and indicate remaining unsettled for the next 14 days Of course there will be day to day variations on the smaller scale when the warm and colder air interact, or as Vorticity more correctly puts it the phase difference, within the long wave pattern as mentioned previously when discussing the general outlook. Thus a continuation of westerly upper flow with temps around average initially and then perhaps dropping a tad below.
  4. 1 point
    It already feels like a solar minimum! Is this cycle turning quieter than expected?
  5. 1 point
    pic of people getting water in a heat wave on the metO is showing them wearing cardies and coats
  6. 1 point
    For the last two years, I haven't used any.. that was starting on Windows 8, and now I'm on 10. I have a good enough hardware firewall, also the Windows firewall, and I just keep smartscreen tight, and that's good enough. I don't click dodgy links - I'll hover them, to check them, if I don't trust it. I don't download crap any more, I go the official route. I can safely say, I haven't had an issue! The PC runs smooth, i've had no browser hi-jackings or bsods, and none of this ransomeware that is doing the rounds. AV software is bloatware in this day & age, it constantly scans files that you might be using, and it is slowing your system down whether you notice it or not.
  7. 1 point
    It's not that bad, after the fine spell it looks like a return to sunshine and heavy, thundery showers with temps close to 70F. There is plenty of time for heatwaves yet, for all we know, August could be a sizzler chin up.
  8. 1 point
    Enjoy this week if you get any sun, from the weekend onwards things are looking truly awful, massive high pressure covering the pole, with low pressure slapped across or near the UK. Can't really see any light at the end of the tunnel either!
  9. 1 point
    despite some decent daytime convective activity, I think this summer has been very poor so far. The only time it has got above 25c has been when I was away in Spain! Don't think I've ever experienced not having reached even a mediocre 25 degrees let alone 28-29 before July has arrived. To think that this time last year we had reached 36c and tonight was the night that many witnessed some spectacular thunderstorms. No sign of any return of heat either in the meantime. A poor show indeed in my humble opinion.
  10. 1 point
    The week ahead is going to become noticeably warmer according to the Ecm 12z with temps into the low to mid 20's celsius across the southern third / half of the UK during the second half of the week, especially southern / southeast England as warmer uppers (T850s) gradually spill across most of the BI from the southwest. The other good news is a ridge of high pressure builds across the south bringing largely dry and fine conditions for a while although central UK has a few rainy spells to deal with early in the week before conditions improve for Wed / Thurs. The fine spell lasts longest across the SE.The NW of the UK becomes more generally unsettled later in the week and eventually the fine spell breaks down further south, possibly with thundery rain / showers as it still looks warm and humid in the south of the uk towards the end of the week. Another ridge attempts to build into the south at the end of the week but the end of the run shows a trough slowly drifting east over the north of the UK so a cyclonic end with sunshine and heavy, thundery showers with temps closer to average but for the south in particular, most of the next 5 days or so look much better than recently, at least feeling like summer again!
  11. 1 point
    Well I used to fix the student computers at Uni and the worst useless ones were Nortons, Mcafee, AVG, Kaspersky despite it's good reviews isn't as good as made out. Okay sometimes the students didn't update and hardly any understood that bigtits.exe wasn't a good download. However the number of times the machine was clearly infected and the virus checker was sat there saying nothing was amazing.
  12. 1 point
    Looks funnel-like to me - but I'm no expert. You don't have to have a CB to have a funnel. Do you? William's comment just had to make me think of "clingons"!
  13. 1 point
    I don't think knocker will ever be on my side, in winter he doesn't like cold and in summer he posts the coolest most unsettled charts he can find.. only joking malcolm.
  14. 1 point
    Am I too late? If not 15.3C please.
  15. 1 point
    Don't give up on a warm / very warm / hot spell developing during the second half of July. The Gefs 6z mean shows support for a warm spell as there are some peachy perturbations scattered throughout, a few hot spanish plumes too so don't give up..keep dreaming that this poor summer will dramatically improve before August! P18 anyone?
  16. 1 point
    The Meto, no, but I do provide seasonal forecasts for a retail chain, that has a number of stores. I would agree, that if someone is consistently close, over a period of time, then that, imo, rules out guesswork
  17. 1 point
    Evening Thunder's anomaly is insane. He must have been on for a record with them sort of figures.
  18. 1 point
    14.4c to the 2nd 0.9c below the 61 to 90 average 1.5c below the 81 to 10 average
  19. 1 point
    Can we please only discuss what the 'Model Ouputs' are showing in here, 1000s of members expect to log in to this thread to read/learn on what the models are showing. There are threads open for general chit-chat and the likes above. Many Thanks, Please continue.
  20. 1 point
    I won last year and will probably be into the top 5 after the latest results are up (was 7th overall after May, but got June spot on), but I can assure you there is little skill involved! Evening Thunder had an average error of just 0.16C for the first 5 months this year, but being a good sport, missed last month and had a few late entries to give the rest of us a chance!
  21. 1 point
    would the transition from El Nino to La Nina be responsible for the change in the poition of the jet stream?
  22. 1 point
    A decent week coming up with less in the way of rain and more in the way of warmth Next weekend doesn't look as good with GFS, GEM and ECM all agreeing on a deep low coming across the Atlantic what its exact track will be remains to be seen UKMO at t144 We may get lucky and see it track north of Scotland or knowing the UK's luck it will head straight for us... Not worrying on that much yet its nice to see a week of temps back in the low 20's and not mid teens!
  23. 1 point
    Welldone on winning a year. I wondered about this. Might prove more is in this than just pure guesswork if similar people are usually at the top
  24. 1 point
    There's already a Summer thread so I'm going to lock this.
  25. 1 point
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