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MattTarrant

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Everything posted by MattTarrant

  1. This should calm people down . Even 5/6 cm further west according to ARPEGE.
  2. GUYS, STOP OVERREACTING TO ONE MODEL RUN!! ICON HAS CONSTANTLY BEING UNDERPLAYING PRECIPITATION (NOT 100% RULING OUT BUT VERY UNLIKELY!) ARPEGE, EURO4, GFS & HIRLAM GOOD, ALONG WITH MET OFFICE GRAPHICS.
  3. Thermal Gradient = Lateral (Horizontal) difference is temperature (850hPa/Surface Temp) between two areas. Lapse Rates = Vertical difference between surface & upper atmosphere. Should of quoted Elly, sorry.
  4. Possible to upload link when available?
  5. Just to settle the nerves a little; HIRLAM : More broad snow (Ie even Swansea West Gets 7/8 cm) ARPEGE: 5cm West Of Swansea EURO4: Likely to be over predicting the effects of the Brecon Beacons. They are a real annoyance but are they really going to wipe out all precipitation on SE to NW trajectory? Unlikely. Met Office automated forecasts also show snow falling for the likes of; Swansea, Ammanford, Carmarthen.
  6. Just have a few points to make; . Andy, please attach charts to support such a dramatic tone. Best to follow the Met Office up until Friday. A selection of high resolution models to view include; HIRLAM, Icon, Euro4 & ARPEGE.
  7. Agreed, however, this is an extremely complicated setup and i don't envy the met office for calling this.
  8. Still too much uncertainty, I safe bet would be 5- 10cm at the moment. Though there will be areas seeing in excess of 20cm. I believe the ice threat is what causing the most issues with that having the potential to cause severe disruption though any the northern extent unlikely to be agreed upon until late Wednesday/Early Thursday.
  9. Important step forward, however, we are unable to see the uppers into late Thursday/Early friday which is a little annoying.
  10. Euro4 - Good (Only missing SE Coast/Inland Region), enough margin of area to travel 50 miles north or south. Hirlam - Was very good (More southerly feature).
  11. I don't envy forecasting this low, GFS is not really budging (maybe a little further east at around 80 - 86hr but minimal really).
  12. Icon followed the GEM & UKMO in that is disrupted the energy east. 850hPa still very marginal but it does undercut the precipitation after a short period of rain/sleet along southern areas. I think we are all in agreement that whatever outcome, be it enegry going east or west uppers will be marginal along southern areas.
  13. I do believe they are horridly inaccurate. The In & cm depths are completely different
  14. Very GOOD ICON RUN! I shouldn't post a snow chart but hey we have a right to be excited.
  15. All of Wales with the exception of Anglesey & the Conwy coast.
  16. An improvement from the GFS, a slightly better angle of attack with a slightly more elongated low allowing for a more easterly component to reduce the advancement of the milder 850hPa temperatures north.
  17. You make a valid point, cold air is very dense. Though its key to distinguish between 850hPa Temperatures (Approx 1500m) & Surface Temperatures in this situation. Parameters of air (mass) resistance is a complex science. I would be under the assumption that as result of our minimal land surface area, the boundary level is more minimal in its affects to fluid flow than would otherwise be the case in a continental country. Such that as a result of minimal cold development at the surface 'warmer' air masses can easily override the cold air in place without disruption or turbulence (Ie remains laminar flow in essence), related to a dimensionless numerical value known as Reynolds Number. The above hopefully will give a little glimpse at the complexities of air mass interchange, especially at the boundary level. You should also hence be able to decipher why there is a lag in surface temperatures over ridden by a warmer upper air component.
  18. Quite a notable difference in regards to the 850hPa temperatures, higher uppers stall along southern coastal areas with gradual mixing out.
  19. Parameters of air (mass) resistance is a complex science. I would be under the assumption that as result of our minimal land surface area, the boundary level is more minimal in its affects to fluid flow than would otherwise be the case in a continental country. Such that as a result of minimal cold development at the surface 'warmer' air masses can easily override the cold air in place without disruption or turbulence (Ie remains laminar flow in essence), I believe this is related to something known as Reynolds Number. Anyway I do believe the macro - scale synoptics are just as important in the whole process.
  20. Model analysis at such a range is based on trends & the probabilistic nature of certain broad scale events happening. History would indicate that cold pooling is often readily removed too fast (often just before the onset of the cold),especially at the surface level. Once we are into the cold spell the models will adjust accordingly, largely a result of snow cover actually physically being in observations instead of in theory. Friday's system is simply conjecture at this range, though a mix of ECM & UKMO would currently be the favored outcome with support from MOGREPS. <10/20% GFS outcome.
  21. I was commenting on the 'WaswallWeather' image which was inches & shows what i was saying. Odd if cm setting would be different.
  22. The chart shown is inches, which would result in closer to 20cm in the south west & 8 - 10 cm across the rest of southern england.
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