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lorenzo last won the day on November 9 2019

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About lorenzo

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    Scottish Weather & Regional Banter. Teleconnections, ENSO, MJO, Research Papers & Learning, Hurricanes, Atlantic Lows & Windstorms, Stratosphere Monitoring
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  1. Some composites based on recent torque action.. Based on individual dates between 20th -30th November > then rolled forward in time. Clearly the Aleutian ridge is a big watch out and then perhaps on a secondary basis the Scandi Block and Jet angle. All of these manifesting in various mid term modelling now so let's see how well the AAM does for predictability... given the core vorticity vacating the Scandi locale as the vortex centroid position pivots back to Pacific I think the scandi high solution would be a interesting catch for this build, given it's not something you would have rightly called out lookng in NWP / ENS etc..
  2. Picked a good evening to get to Cairnpapple for a nice view of the sunset.. Got to love low winter sun and High Pressure. Perfect.
  3. It's laid out beautifully A Monday's page updated overnight on Tuesday to include the Vimeo Link and PDF - hopefully this will continue this week and the archive remains for a bit.. KW is right they are all on Vimeo - this link lays out the vids with the presentations. Workshop: Stratospheric predictability and impact on the troposphere (18-21 November 2019): Programme · ECMWF Events (Indico) EVENTS.ECMWF.INT #StratosphericWS This workshop will bring together experts to discuss and propose ways forward in representing the stratosphere in current and future numerical weather prediction models...
  4. I got to the point last weekend Catacol where I just couldn't reconcile the seasonal output with that the statistical evidence was pointing toward... hence the tweet confirming as such. It really feels like it's an 'Us vs. Them' thing at the moment - not in a bad way - but either way it is a bit of an all or nothing situation where either the seasonal leads are defective, or, the reliability of looking back to look forward is flawed to a major degree. Have chewed it over plenty around the fact that the seasonals, perhaps to my naivety in understanding their input matrix, to my mind I thought they must have this stuff we amateurs / speculators look at built in to the ensembles. Or, perhaps the game here is not the 'perfect evolution' but a slow build to improved skill, more improved skill, what creates better skill and improves the correlation. Certainly having watched the symposium this week it is clear that there are hardcore questions on offer around what to 'go after' - 1 The processes and understanding of interactions vis a vis - we have enough resolution with the models 2 Increasing either the Vertical or Horizontal capacity within the modelling -which will generate enhancements in skill. 3 Hot Topic - impacts of GWD - Gravity Wave Drag and the contest between Direct Inputs vs parametrization. Am a Layman but if I was consulting I think I would ask the audience to Action Plan on 1 - which process the community should address, pick Horizontal to capture internal vortex vacillation and liase with MERRA for part 3, in particular their 132 level model. So these are there real challenges in resolving predictability, then impacts and it's been a good watch to review them.. I just hope we get a strong answer either way and not a halfway house solution where the answer fits elements of seasonal and elements of statistical..
  5. I hope Stewart @Glacier Point won't mind me dropping this into the thread. Hugely respected poster on here who is currently not active. Some thoughts on this blog which I happened on this evening for folks to add into the Seasonal forecast mix. Solving the winter conundrum – Centaurea Weather CENTAUREAWEATHER.COM It’s that time of year again when the energy sector, hedge funds and weather enthusiasts are deluged with long range weather forecasts, the key question – what will the winter hold ? I’ve been...
  6. Rendered this on gif from Zacs page earlier, pretty much sums up the current carnage... Lower vortex - shredding and shearing with filaments slicing off here there and everywhere. Core of Vortex - W1 doing it's thing and chomping into what appears to be a neat cylindrical funnel at points. End of run - we see the distended upper realms of the vortex where the real heat flux is in play and also some tilt to the vertical structure. Would be nice if MERRA ran out to further timeframes - but we cannot be too greedy I guess! If we think on that monster W1 and the physics in play I think on reflection it is little surprise that we will see some 'chaos theory' in the u deceleration ensembles, they just won't have it crystallized as of yet, hence the small cluster of members dipping below 0 and then a couple a few days later. Yes, it would be great to have something more positive to lock down from a GloSea perspective, but we still have the -NAO in it's infancy, a primed vortex via the W1 and lots to play through the column at all angles.. Anyone predicting where this goes is in the wrong place - esp. given the symposium this week where a room full of experts were divided on 3 > Colder conditions , 5/6 > Seasonals and essentially the rest were IDK... Am torn between the W1 resolving like a 'classic / old school CW' then retracting and the Intensification period continuing until the next MJO cycle comes round, this time aided and abetted by perhaps a more suggestive eQBO profile and another few weeks into deep zero solar. Vs. this W1 having been so anomalous that one of these consistent CWB /ACWB over the Atlantic region is the proverbial 'butterfly flapping it's wings' and the vortex internal resonance suffers some internal vacillation collapse into split mechanics. Would happily take version 2 of those events! Esp if an MJO rolls through at pace 8/1/2 mid/late December and layers the Greenland HLB over the QBO and Solar background states. Oaft.
  7. Proof that disconnect delivers... great contrast during that February and a really unusual alignment of HP anomalies vs a bullseye Polar Vortex, nice rewind there!
  8. In 2018 NAO tightened ahead of SSW, this is something I thought was linked as an artefact of all vortex events ahead of an SSW, given strong anecdotal model watching. No one was wrong, we were possibly observing other things simultaneously, trough disruption, MJO/AAM Imprints Dr Butler confirmed it is not analogous, ergo cannot be a confirmed regime watch out on NWP... More stuff to observe lays ahead and - no comfort from NAO heralding an SSW.. Although it did last year ? From Dr Amy Butler https://twitter.com/DrAHButler Lady is the boss folks - ? privilege to get insight like this
  9. SSW in Dec as a whole I think could be considered rare given that is the canonical Vortex Intensification period, happy to be challenged on that view however.. I think without pulling out any papers that statistically January is your go to month for SSW with December being very much the exception, still gobsmacked by the EC Seasonal update to be honest - the plot for December shows an SSW with the Ensembles posted earlier showing the cluster heading that way. Then, January plot is also a torched vortex, if that came to pass then we are in for a ride this winter. What is also interesting is that this November feels like a throw back to when Novembers featured Canadian Warmings back at the start of the 80s, given last November saw considered action also, just a few years ago we were wondering about whether Canadian warmings were actually worthy of classification, or a nuance of the early satellite era capturing more detail and then requiring classification of a kind. Rambling now... onwards and upwards with the wave breaking !
  10. Given the EC Seasonal ramping up some excitement, and not without support, given the CFS also cottoning onto what would be a rare December event. Here are the precursor height anomalies for each of the previous December events. I have left out 'December 01' as this event took place on 31 December. Each plot is annotated with the year, QBO regime and strength of reversal by way of how decelerated the u at 10hPa went to, dates also annotated so this is not a November anomaly, but the 30 days prior for each event. One to reflect upon of we do have an SSW next month whereby we can look at what is happening tropospherically now and maybe draw some inferences, equally as November progresses and the anomaly picture builds out we can perhaps map what we can expect to see if it looks like the EC seasonal etc will eventually deliver a December event. I know I said November was fast becoming the most interesting of winter months, didn't expect it frankly to be as exciting as this..!
  11. Have a look at the ensemble members dropping below the 0 line for December.. Here is a box and whisker plot Simon posted representing the shift from the EC Model from Nov > Dec.. The thing that caught me out was this box forecast time 2020-01-01 - which anyone in their right mind would load in and say cool - this is January, however due to the way the data is encoded this is reflective of the month prior, in this case December.
  12. Okay so the plots from last night looking at January >>> scrub that... these are for next month ? Thanks to Simon Lee for messaging to highlight as the way the dataset presents on Copernicus caught him out too!
  13. Nice one @Recretos, that EC Jan plot is a beauty.... you beat me to it rendering the data. I had a confusing Grib error that I had to dig into notes from @Interitus to resolve. It's certainly not messing around for January... Correction - DECEMBER
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