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Mark Canning

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Everything posted by Mark Canning

  1. Not to dwell too much...but it's interesting you both have this view..because from my point of view it was extremely well forecast, considering the complexity of the set-up and multiple trigger mechanisms. However, unfortunately it seems this info was not disseminated to the public in a way that reflects this...
  2. Apologies, UKPP = UK post processed, a suite we have here at the Met Office, which means our model output from the Unified Model has additional algorithms and corrections applied to the raw data to better fit reality. At the shortest lead times (the next 6 hours) Nowcast data will be blended, then UKV (which is the Met Office high resolution model for the UK, with a resolution of 1.5km), up to Euro4 for the longest lead time (the Met Office 4km gridded model covering the Europe domain). So what I was referring to earlier was post processed output from our highest resolution model, regarding th
  3. As I alluded before it's hard to compare as it outputs dilute CAPE, which is cloud base to cloud top. It's actually scaled to 2km, for rather boring and fiddley reasons. Unfortunately probably cannot post charts, so I won't haha. But interesting to see 3hr ppn output (18z-21z) as well from UKV (have not looked at anything else that's in public domain, maybe other output agrees?) with lincolnshire looking most at risk and isol SE/London by 2100z tomorrow. Considering no dynamic activity tomorrow, these can be assumed convective so further support potential for some storms about!
  4. Yup, could get some moderate values, though not comparable to the storms earlier in the week though! I'm looking at UKPP, which is post processed data to match location better from UKV at this lead time.
  5. Not sure if common knowledge or not...but GM (UKMO) breaks down blocks faster than it should as a function of the statistics that output the verification index..so in short, more often than not, it gets it right, as more often than not, HP does not dominate and GM pushes us back into a zonal pattern consistent with climatological mean. (the model looks better, scores higher, we get it right most of the time). So, if GM keeps block for a long time, this is quite interesting as it is going against its internal revert to zonal flow after 3-4 days...so we can gain good confidence from this. I woul
  6. Our post processing spits out dilute CAPE, and has values of ~700 max (generally 400-500J/kg) in south, central and isol northern UK later tomorrow afternoon, so not directly comparable, but perhaps not as severe as the graphic above posted by Liam. I'd say though there is a great degree of interest (and has been since Monday) in the destabilising effects the over-running trough will have for profiles in south and central UK tomorrow evening. Maybe even Wales with orog uplift late afternoon...As the upper short-wave trundles through cold advection could erode warm noses from the 15C theta-w pl
  7. It looks like most of this warmer weather, if it comes, will be held mostly to the E, with western areas seeing more of a wetter outlook. Past Saturday solutions start to become varied, with ECM and GFS pulling a plume up from the continent. This could bring warm, or even, hot conditions (outside of the climatological mean). Confidence is reasonably high, with MOGREPS on board too. However, depending on what happens on the continent, and what any engagement with this plume might result it, is still uncertain. Whether or not the vortex off the SW of the UK into the weekend retrogresses will hav
  8. Hi Harry, I noticed you asked me in the previous thread about which model was showing high values of CAPE...today, again, UKV was putting >1500Jkg-1 of "dilute CAPE" (apologies if I failed to mention this before, not quite the same as CAPE, but still these values aren't often seen) across areas of the SE and London that are quite concerning, for tomorrow afternoon. Dependant on surface heating in the morning tomorrow (which should be relatively sunny in that area of the country), some deeply convective t-storms may be triggered with localised accumulations of up to 40mm/24hr for some isolat
  9. Thursday looks promising for those after storms...latest models putting CAPE at 1500Jkg-1 plus in some areas. Will be worth watching tomorrow, and seeing what the chief says. Also would not be surprised to see a warning from ESTOFEX. In the meantime, enjoy tomorrow's sun whilst it lasts!
  10. It does look as though the weather will rapidly deteriorate after the weekend, which for most will be the warmest of the year so far owing to a fair amount of warm air advection. At the moment there is a degree of uncertainty around whether or not some pretty heavy isolated storms may break out in the S/SE by Saturday, so it might not be BBQ weather for all!Regarding post Monday though there is still a large disparity between the models, so confidence is low as to what to expect... EC det allows for cyclogenesis in the bay of biscay, which would lead to most of next week being pretty wet and w
  11. As mentioned already it isn't easy looking at simple synoptic charts of parameters such as pressure or temperature to try and identify fronts. However, if you have access to charts with station circles and begin to plot a few simple variables, such as isobars, isodrosotherms (areas of equal dewpoint - very useful as different air masses will have different humidities, and a front divides airmasses!) and try and spot wind veer...combine that with simple knowledge of clouds and types of weather you'd expect along different fronts and you'd actually not do too badly identifying where they are!
  12. Well 30 years ago the 24 hour forecast was as accurate now as we can go out to 4 days. So that is some achievement in itself! In the near future though, more computing power would not give us anywhere near the accuracy we have for 24 hours for a week out. A lot of other things need to be improved before that!Incidentally, within the next year or so, we will indeed have more computing power here at the Met Office (as a new supercomputer is soon to be purchased, the most expensive yet!)
  13. (purely biased towards MetO)For the Met Office, in terms of skill and verification improvements please consult these links;UK NWP Index - http://www.metoffice.gov.uk/research/weather/numerical-modelling/verification/uk-nwp-indexGlobal NWP Index - http://www.metoffice.gov.uk/research/weather/numerical-modelling/verification/global-nwp-indexForecast accuracy and how this is measured - http://www.metoffice.gov.uk/about-us/who/accuracy/forecasts & also http://www.metoffice.gov.uk/media/pdf/d/h/13_0068_Accuracy_v09.pdf This is not neccesarily the thread to discuss how models reach their solutio
  14. Seeing as we are discussing the chances of snow, here is some supplementary info regarding various parameters and their relationships with the likelihood of snow... (all from the Met Office, for educational purposes)..Probability of snow________________90%____70%___50%___30%___10%Surface temp ( C ) _________________+0.3____+1.2___+1.6___+2.3____+3.9Height of 0C isotherm agl (hPa)______12______25____35_____45______611000-500hPa thickness (gpm) ______5180___5238__5258___5292____5334 ______ (the "528 line" falls around 40%)(mutually exclusive)Based on WHEN precip begins, as mentioned above latent
  15. When looking at upper levels for indications of snow, perhaps the 850hpa theta-w is worth paying more attention to rather than 850hpa temp or 500-1000hpa thickness. A general rule of thumb for the UK is that an 850hpa theta-w of 2C or below can allow for snowfall down to penetrate down to all elevations (with a large number of caveats obviously).Based on the 12Z run of GFS, we are likely to see most favourable theta-w temps on Tuesday evening. However no significant precip is forecast for this period..maybe some flurries across Wales and the East Coast..
  16. Tignes was operating with 8 lifts open today, blue bird conditions and 220cm of snow at the top - some great conditions for this early in the season!
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