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Eagle Eye

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Everything posted by Eagle Eye

  1. Paper from one of Reed's tornado measurements has been written up. Will be an interesting read. https://amt.copernicus.org/articles/17/943/2024/
  2. 12Z GFS has helped set the trend towards a split semi in stone, much better than all the displements runs earlier. Hopefully the trend continues and better. Still quite far out.
  3. Singularity Problem with the major SSW is that if it does happen, most of the runs appear to be wave-1 displacement driven with most of the vortex over Europe so favourable surface responses at the moment are looking a bit meh. So I'm not really thinking those March's are likely at the moment but we'll see. I really would warn people here getting excited over the modelled SSW, no matter the strength it's really not looking the best, arguably the worst scenario considering some runs saying about - 15ms zonal mean zonal winds. Most of the deterministic runs have been displacement type for a while. I'm still hanging onto hope but this feels like it's not going to end up well.
  4. Secondary AAM rebound appears to be well underway, momentum being added to the atmosphere, significant jet shift surely likely for the NPJ, perhaps displacing the Pacific trough as has been expected for a while. This appears to be helpful in Greenland high forcing still. Interested to see how accurate the response forecasts tend to be in this scenario. Original post: https://community.netweather.tv/topic/99814-model-output-discussion-22nd-jan-2024-onwards/?do=findComment&comment=5031468
  5. Secondary AAM rebound appears to be well underway, momentum being added to the atmosphere, significant jet shift surely likely for the NPJ, perhaps displacing the Pacific trough as has been expected for a while. This appears to be helpful in Greenland high forcing still. Interested to see how accurate the response forecasts tend to be in this scenario.
  6. Let's talk SSW potential. What we don't want is the GFS 06Z to be repeated, it's an example of a wave becoming baratropic-ally stable before a wave-2 can occur and that leads to when the EHF disconnects (which is the switch from a baroclinic wave to a baratropic one) it's a wave-1 diffusion into the polar vortex. What that'll do is disconnect and stretch it but clearly Eurasia-ward. It's then both easier for the vortex to recover and become baratropic (vortex like) even when displaced right over Europe. Easily leading to a state where we're relying on a strong Greenland high surface response for any luck here as the SSW would be another negative for us and even that that's not looking good on the 06Z. This appears to be a trend with the GFS and has been the outcome of many recent SSW's over the last few years so I'm sort of inclined to believe it, the timeframe for a wave-2 being fairly short. It's another multiple rounds of wave-1 due to timing on the 06Z GFS, could well end up in a major SSW but later and still displaced based most likely. As once the EHF pushes polewards, it won't recover on the wave it just disconnected on. Timing as ever is important and it's currently an uphill struggle. Just a warning. Hopefully the 12Z is better. Away from the Strat, GLAAM on the rise soon/potentially now if it can maintain and w/the already +VE GLAAM and MJO 7-8 phase during a late Winter El Nino and enhanced Western Pacific-western Hemisphere (slightly) convective envelope then we have good support background signals wise. Greenland high easily supported at the moment later into February, how much that is helpful will depend on basing and actual strength of response. Good tropospheric signs but we're running out of time for them to produce.
  7. johncam Yeah, Greenland is the easiest to get cold from unless you get certain angles of Scandi high really but I don't think Winter is over yet, still got the possible SSW and about a month left.
  8. johncam Greenland isn't the only high available that's good for us.
  9. johncam Greenland high quite possibly there which is also supported long term by the GFS unless I haven't got the updated EC46.
  10. AAM tendency definitely down over next few days but the actual total momentum ignoring the tendency is still +VE easily compared to recent and long term averages, any +VE EAMT event soon would lead to probably the largest AAM response of the Winter.
  11. Mike Poole Yes very interesting to say the least. Good thing is that it's - VE NAM drive so should reflect back a Greenland high so could reinforce an MJO-GLAAM driving Greenland high if that were to occur. Looks to be driven around this time.
  12. Major SSW on the GFS 00Z run on Stratobserve, the trend has been going towards this for a while. Good wavebreaking for a QTR if it did occur. Just something to keep an eye on.
  13. Can we pretend this isn't at like day 15. Its a CAD episode if it did come off.
  14. Mike Poole Great post. Yes models have been under modeling the MJO for a while now, suspected it was possible as we got close to these phases as well, happy to be right, good to know I understand something well I guess. It's a classic of undermodelling both suppressed and active phases during outside influence. "the GFS slightly above but as we go further towards the future, they move very close together and phase 5-7 are more responding to a quickly falling -VE IOD (a fairly strong wave strength response but it's not the only variable, just 1 of the MJO spread inputs) so potentially may be underdoing the strength of the active western Pacific response further away from the western Maritime region slightly infiltrated w/dry air occluded into the far western Maritime region likely in response to the trend away from a +VE IOD, not a full on dry response but not as +VE wet as the normal composite and that dry air into parts of the Maritime region. Whereas a wetter than normal eastern Maritime and western Pacific that has been characterised poorly by the GFS so far. Theoretically leading to a larger response in phase 7. " The MJO forecast strength during times of extreme IOD change especially but also other outside influences definetely needs to be taken w/many pinches of salt.
  15. Mike Poole I'm never entirely sure of the MJO, it's not my best subject but appears to be a new cycle sort of forming but not far behind the last one?
  16. The GFS 12Z is a very familiar scenario for the south In all seriousness, good set of runs. Perhaps a trend in the right direction.
  17. MJO phase 8 and built-up momentum response likely late February or into March. There appears to be a good chance of a phase 8 w/the w'ly moving w'ly burst as the slow Nino-neutral/Nina transition occurs and the phase 7-8 is also typical of that transitioning time. However because of the w'ly burst, perhaps the response would be more neutral/Nina esque. The MJO low pass appears to suggest neutral with slightly more amplification with the momentum. As we get into March we really need more amplification though. Given the potential before this in mid-Feb isn't looking as good as it was before though there's some decent colder solutions in the spread.
  18. Second high-rise GLAAM by mid Feb possible, stronger than this one. Would have a response into March depending on the MJO. However, not sure of it yet as its kept being delayed by the CFS.
  19. @Tamara Another great post but would it be more accurate to use +VE MT rather than describing just the EAMT given the NAMT strength, rather than EAMT each time, I'm guilty of using EAMT to describe it each time and whilst that is the strongest and typically is, wouldn't it also be a synoptic scale change from the +VE NAMT as well to consider so more accurate language to be more general?
  20. As the AAM rises, the motion derived from it also rises so I've used the forward motion rebound deviation to show the AAM rebound, this won't show distribution but it's important for showing the AAM contributions and is much more real time than the CFS updates which seem to occur randomly and the GFS updates are only daily. However, we can't really derive a forecast from this but it shows how sharp the rising AAM has been over the last few days as the tendency is such a steep gradient. Will be important for built-up momentum if we do get that mid-Feb phase 7 response (lag probably mid-Feb).
  21. Doesn't really mean anything, just a function of the westerly moving Canadian high, a break from the Canada PV lobe for a time, perhaps more Euro ridge building so milder and drier but not much else.
  22. A sudden wave of despondency in here again with the EPS, still looking towards the 2nd week of February for any potential but phase 7 MJO and high built-up momentum appears possible by then. Said all that needs to be said for now already.
  23. @sebastiaan1973 I suspect it's quite rare but I'm fairly new to these.
  24. GLAAM tendency now significantly +VE. W/all +VE MT, especially east Asian and north American but also tropical momentum rising. Therefore the momentum built-up forcing w/MJO phase 7 is a potential high-lat blocking pre-cursor for mid-Feb but there's still MJO phase uncertainty.
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