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FrenchScotPilot1

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Everything posted by FrenchScotPilot1

  1. I'm after an explanation about the link between Mountain Torque (there's one in Asia just now, so it is topical) and SSWs. What is the physics behind it, what happens during the event? Many thanks!
  2. Does it not depend on where the fragmenting vortex goes and how it intereacts with the blocking high? Is it fair to assume that it will always strengthen the block? EDIT: Disregard. Chiono answered as I was typing.
  3. I haven't had much time yet but I now take this opportunity to repeat what has already been said: thanks very much Ed and other contributors to make this thread, abeit quite technical, VERY VERY interesting and informative!! It really furthers our knowledge of atmospheric physics every time. Best regards, Stephane
  4. On behalf of one of my estimated twitter user, find below something about Global wind Oscillation (GWO). GWO is arguably the best all round measure of atmosphere because it encompasses GLAAM (see above), Rossby waves, responses to torques (which include global patterns like nao, pna, etc...) and MJO if coherent. What is missing now is a composite comparison height anomaly set of charts. Another bit on Atmospheric Angular Momentum (AAM) and espacially its calculated tendency relative It includes (Gravity Wave Drag + Coriolis + Mountain + Frictional) Torques + Relative AAM Flux Convergence It is shown at the bottom of the page: http://www.esrl.noaa.gov/psd/map/clim/aam.90day.total.shtml
  5. Great link here to teleconnections technical papers http://forum.netweather.tv/topic/73911-technical-teleconnective-papers/ but it would take years to read them all and summarise findings. What I had in mind was (and I hope it is not too naive/utopistic) AMO, PDO, MJO, ENSO, AAM, etc have the following effects on European weather: AMO: effects PDO: effects MJO: effects ENSO: effects AAM: effects etc...
  6. On behalf of one of my estimated twitter user, find below a random bit on Globally Averaged Angular Momentum (GLAAM). It's assessed as a global (averaged in latitude and longitude) anomaly of AAM. [*]+AM in late summer normally equates to neutral NAO with ridge in mid latitudes [*]+AM can help develop ridges at high latitudes in winter months [*]-AM can help develop ridges in high latitudes in summer months For info, last March ('13), which was ended up the coldest in 50 years, had a very defined positive GLAAM. Climate indices, monthly atmospheric and Ocean Time Series: http://www.esrl.noaa.gov/psd/data/climateindices/list/ Note: This post will be edited as and when.
  7. Thanks Supercell89. Ok, what do Iknow so far when it comes to global influences. It's a bit like paper rock scissors: Sun influences SST. Atmosphere and Ocean influence each other (ENSO). ENSO influences MJO. MJO influences upper/lower tropical winds. Upper winds influence pressure patterns (e.g. jet stream drives NAO) Oceans drive PDO and AMO. AAM is the result of frictional torque (surface friction) and mountain torque (pressure difference on W and E side of mountains). AAM is conserved therefore changes are done through torques above. Stronger W'lies = Atm AM increase = Earth AM decrease Atm AM increase with E'lies in the Tropics, decrease with W'lies in mid latitudes. There is therefore a poleward trasfer of AM. ENSO changes E'ly trades into W'ly trades. Atm AM increases, Earth AM decreases. This is what I have so far. My next read is on GWO vs MJO.
  8. I'm creating this topic as some sort of research thread to try to establish how we could improve long range forecasting (1-3 months in advance) using teleconnections and variability indices: QBO, ENSO, PDO, GWO, AMO, AAM, Mountain/Frictional torque, etc... Some analysis/forecasting sites to start with: AAM, Mountain/frictional torque: http://www.esrl.noaa.gov/psd/map/clim/aam.90day.total.shtml GWO, MJO composites: http://www.esrl.noaa.gov/psd/map/clim/gsdm.composites.shtml GWO: http://www.atmos.albany.edu/student/nschiral/gwo.html MJO: http://www.daculaweather.com/4_mjo_phase_forecast.php TIGGE MJO: http://tparc.mri-jma.go.jp/TIGGE/tigge_MJO.html MJO composites: http://www.americanwx.com/raleighwx/MJO/MJO.html Various: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/climwx.shtml Various: http://www.ncdc.noaa.gov/teleconnections/index.php And there are many many more. We could also include SSW. I've laid out the foundations, please start building the walls :-) Let's make it a great place to learn...
  9. With High to the E and S'ly winds, models give warmth for start of next week (above 15 degrees away from coasts). Let's see what really happens.
  10. Looking for a good clear explanation about atmospheric angular momentum and how it affects jet stream, northern blocking and ultimately the UK weather in various season. Any pointers guys? Thanks!
  11. The 7 plagues of Scotland? Grasshoppers are definitely replaced by midgies!
  12. Congratulations! You haven't told her about the weather or about getting married
  13. Glorious bright and cold morning, waiting for wind and rain I suppose...
  14. Well, charts for Saturday/Sunday bring very warm tropical air via a rather deep low W of Ireland. Temperatures at lower level look to be in the mid teens on Sunday afternoon, so I'd expect the snow to go away pretty fast. I like snow too and we've been blessed a lot this year but we had to expect warmer temperatures at some point.
  15. Moderate snow coming off a SE'ly direction for the last 15 minutes in Aberdeen.
  16. GFS show some heavy precipitation Wed/Thu from the low SW of Ireland tracking east too. Unsure about snow yet and Scotland specifically, I'll need to dig deeper into it. Never ending story, feels like...
  17. As explained above, moderate sleet/snow has started over Aberdeen 30 min ago. Nice to see flakes again. Ok after this, spring warmth, promise
  18. April sun provides quite mild conditions during the day (circa 8C) but the very cold 850hPa air (-7/-8C) makes them drop again below freezing at night. The consequence could be one new (last?) snow/sleet attack tonight from the cold front moving from the N. During the day, the last few hundred feet temperature profile is positive but, at night, the whole profile is in the negative range. Mid month onwards, 850 hPa temps look to get positive and stay around 0. Tentative spring is likely to appear at this point. AO and NAO becoming neutral should ensure that no further incursions of cold air disturb the spring plan. Ideally, they both need to be positive to see proper spring temperatures.
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