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MattHugo

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About MattHugo

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  1. Cheers that and yeah, had a few tweets out about that last day or so. An interesting development. Clearly no sign, IMO, of any helpfull MJO activity into the more important P4-5 phases moving forward, meaning the supression phase and general E'ly bias in 850mb ZWA will likely continue through the I/O and into WPAC. It's interesting how the pattern, again 850mb anom wise, has reversed from back of early June and that significant burst of E'ly trade winds in late June no doubt was responsible for the significant -MT event, bringing the global value down as low as it has been for months. No surprises then really that the AAM has dropped off and the last GWO update ends up in transitional/neutral phase 8. It'll be interesting to see what happens here, whether that W'ly anom 180 and east can be maintained or whether that will get nibbled away at moving forward with, therefore, much of the Pacific then often E'ly dominant. If there were signs of a significant MJO event then one would perhaps suggest that there would be a greater risk of the AAM rising, along with a recovery in the GWO into P4-5, perhaps even P6, especially if any WWB 'combined' with the on-going W'ly anom east of the dateline, but that just doesn't look likely. Used the analogy a week or so back but like a steam engine running of fuel, it eventually and gradually stops, could that well be what is happening now, as you alluded to in your post, with regards to the overall Nino pattern that has dominated for weeks and weeks. Certainly doesn't bring much hope for any significant summer synoptics for here in the UK, not that I can see moving forward. Matt. NB: Worth dropping this chart in as well as I've been watching this in recent days/weeks and while it is the CFS, there's definitely been a quicker downward trend towards a more neutral value than was perhaps expected so early and with clearly now a large number of members more significantly -ve as well looking forward. As you mentioned a neutral or even weak La Nina may well be on the way for the N Hem winter pattern which when combined with the QBO phase and the solar min could well be very interesting indeed, but that's for further down the line!
  2. Hi all, quick post... What is certainly developing within NWP is the return of the dreaded Greenland block once again. The persistence of the NAO to be -ve is now beyond impressive, since May, especially so after being so perisstently +ve for such a long time. Clearly, the topic of discussion here is based around whether this persistent flip is directly related to the late SSW, potential sea ice developments and the obvious approach to solar min. Perhaps it's a combination of the lot, again a topic of discussion but it is without question that the downwelling through May continues to be in evidence, albeit in a watered down situation given the below plot... The other graphic just cobbled together below highlights the latest EC and GFS ENS mean output for approx 10th July onwards. Clearly, the blocking over Greenland returns and there is very good support from within the EC Clusters for this evolution as well. A general reminder of the opening 21 days of June is also attached with clearly the Greenland blocking in evidence and strong -ve 500mb anom over NW Europe, along with parts of the NE of the USA as well which clearly continues to have a distinctly "average" summer as well. The persistence of the NAO to be -ve, again, is quite impressive and for those out there who are Twitter users will clearly have seen a number of other images doing the rounds with regards to this as well. Unfortunately the GSDM charts are stuck on the 28th of June, for the last update, hoping no issues here with data feed and it'll kick back into life. Therefore can't really advance too much on what was discussed last week. Personally, I still believe that the significant trend in -MT, especially around 30-04N through late June will have some influence in creating a more zonal, W'ly type through the mid-lats as we move towards and beyond the first week of July. This may well time badly with the potential Greenland block and, thus, we end up with the dreaded southerly tracking jet of which has a track and position more suited to the autumn and winter months. As Tams alluded too mind, there has been a clear reduction in the strong E'ly trade burst and there is clear evidence for a W'ly regime here looking forward...compare and contrast the below... That is quite the change, especially around the dateline eastwards to near 90W. In the last MT GSDM chart there was a rapid up-tick in the N American plot, which is clearly to be expected, but the others continued to fall and that maintained sub -2sd global -ve MT event, the lowest in months. As alluded too and discussed in my last post and also from within information and posts within this thread, that is likely to have some influence through the mid-lats, at least for a time. Clearly, the introduction of a W'ly bias from the dateline eastwards is of note and this will no doubt combat this recent -MT event. What is an interesting question is; why the sudden reduction in the trades? - This isn't, to me, directly related to the recent MJO activity which clearly hit the 'brick wall' of E'ly trades in late June and then died into the COD, so why the reduction? That aside and focusing in the next, say, 7 to 14 days, perhaps out to 21 days and, IMO, it doesn't look good at all from a summer perspective across the UK/NW Europe and perhaps the NE USA either. With NWP support and the dots being connected nicely then after say the opening 7 to 10 days of July, the outlook looks poor, perhaps very poor for those wanting some 'proper' mid-summer weather, where we go from there will be very interesting to see whether any recovery can arrive through late July and August. A decent end to summer is well overdue, not had one for quite some time, so perhaps this year. Kind regards to all, Matt.
  3. Just an addition to the above, but looking at the latest update, the global MT drop seems to be the most significant fall, along with the tropics, in many weeks. Now, from what I've picked up on over time, it seems prudent to suggest that such a -ve MT event leads AAM by a week to ten days or so. Therefore, is/would the prediction thus likely to be for us to see an increased risk of -ve AAM (E'lies) through the tropics and sub-tropics as we move through and beyond the opening week of July. Thus, therefore, increasing the chances of W'ly momentum through the mid-lats? I still can't explain the lack of -FT or +FT mind. Equally, the other piece of the puzzle is if we have had a MJO/WWB then why, in theory haven't we seen a +FT, but are clearly seeing a -ve MT situation evolve here and I think the anom below really does stand out as being noteworthy. This would, in theory provide further support that after the more anticyclonic start to July across NW Europe, this doesn't mean it's a pattern that will 'lock in' to provide weeks of summer-like weather for the British Isles and thus signal a more cyclonic/unsettled spell of weather as July progresses. Thoughts?....
  4. The above anom plot does still seem as though it will make an appearance moving forward. The 00Z EC anom matches that evolution well, with the trough-ridge-trough-ridge-trough-ridge pattern evolving from over the Pacific, into the USA and out into the N Atlantic to influence the UK's pattern into the opening week of July. It is interesting how there has been quite a 'sudden' shift towards a more anticyclonic rise in pressure, from the W, through early July. Is this being influenced by the recent MJO/WWB activity and resultant upstream changes I wonder...one would suggest it's a possibility. It is also interesting to see how the latest EC Monthly, for approx the same time period mirrors that evolution as well. However, it continues to promote a more cyclonic pattern returning once again towards the mid-July period with northern blocking in evidence. Looking ahead and the comparison between the ZWA's from the 19th and the most recent plot from the 24th continues to provide a lot of uncertainty. Clearly, this is just one snapshot and scenario, but after the predicted increase in the trades, which is clearly present now around the dateline, there is evidence for those to weaken. The forecast from the GFS, especially between say 60E and 120W looks highly 'confused' with neither a dominant W'ly or E'ly type present. This, to me, provides more questions than answers at the moment as to whether a more dominant W'ly type will appear or whether the trades will become more dominant. While the usual 2-day lag doesn't help, there definitely seems to have been some developments from a MT perspective with rather than interesting divergence in output there. The more obvious rise in from the tropics and S America, perhaps some influence here, again, from the recent MJO/WWB through to the dateline, but my experience here is lacking. The AAM plot does, however, show no signs of falling, in terms of total AAM. The plots from Victors site where rather alarming with regards to the drop off in AAM, but, for now it doesn't look like that will take place as modelled by the GEFS with the AAM clearly steady away at near +1sd and, if anything has risen somewhat over the last week or so. While Tom's "warning" regarding placing too much of a direct link between the AAM and resultant MSLP and 500mb anoms is headed, clearly there seems to be too much of a coincidence here with regards to how the N Hem pattern has and continues to evolve given the marked reduction in the E'ly trades in association with the recent MJO activity. While clearly this did hit the 'brick wall' of E'ly trades, it succesfully progressed through the important P4 and into P5 phases. However, there does seem to be more questions than answers at the moment, because there doesn't seem to have been any obvious FT event, but clearly there has been some development in terms of MT activity, after a particularly 'benign' period through late May and into early June. Looking ahead as well, where do we go from here? - There is some evidence now for the MJO to immerge back into P1-P2 moving forward, but no real obvious push for another P2-P3-P4 event, so any signficant return to a WWB looks unlikely to me, while the decrease in the trades also provides further uncertain and confusion looking ahead. Regards to all, Matt.
  5. Interesting commentray and replies. Not much to add at the moment, the overal evolution, to me, remains similar. Certainly some influence from the recent MJO/WWB but as the below animation highlights the propogation of the E'ly trades back towards 120E is gaining some traction. To me, looking ahead, the outcomes remain similar, once we progress beyond the end of June, it's likely that the N Atlantic and NW Europe pattern will often be far more trough dominated, than the other way around. Equally, it's interesting to note the last EC Monthly as well which really 'ramps up' the signal for a cyclonic first half of July with pronounced -ve MSLP anoms across the N Atlantic and into NW Europe. The hope that the more Nino profile will be maintained is still there, but to me, compared with the last few months, at least, it seems to be loosing the fight, especially with the way the SST's are setting up as well. No quick changes, but as we have just recently seen after the pronounced WWB/+AAM anoms through May, the reverse through June has certainly been unhelpfull in getting summer off the ground. While it is interesting to look back at recent years, it is, from experience, often a 50/50 bet when it comes to pattern matching to years past, but here's hoping the above discussions hold some truth and we do see an overall progression towards more sustained summer synoptics through mid-to-late summer, but, personally, I'm not seeing that at the moment, or at least not until mid-July. Late July and August remains anyone's guess... Kind regards, Matt.
  6. Quick update... Looks like, depsite the 2 day lag, some potential influences from the MJO/WWB even though it continues, or is forecast to make little progression beyond the dateline. Quite a noteworthy spike in tendency, than compared with of late and, finally some movement of the GWO into P4, perhaps getting around to P5, but given latest predictions I wouldn't expected to get any higher than that!... What is interesting with the GFS forecast output is how over the last few days it has trended towards what the EPS was showing from back on the 16th, last available chart that I've managed to get hold of. Note that extension westward of the E'ly anoms through late June as the overall WWB eases. You can also see from the usual MJO RMM plots as well how the current MJO has just 'died' as it has entered P5, clearly in association with the interaction of the trades and with this current MJO activity site to die off within the next 5 to 7 days tops. The other few charts of interest are from Victor's site. The long-standing spike in AAM is still there, short-term, but notice the continued fall from the CFSv2 output. However, what stands out massively, is for the GEFS BC chart to suddenly 'come alive'. I'm not sure why, but this has been persistently 'off the scale' in recent weeks, but that, to me, is a noteworthy fall in global AAM looking forward through into early July and beyond. As per my last post, it looks increasingly like that the long-standing +ve AAM/Nino profile may well be about to come to an end, or at least weaken significantly than compared with recent months. . The current MJO/WWB most certainly seems to be having some influence on the downstream pattern with next week, the final week of June, set to bring a greater risk of summer-time blocking and the first heat of the summer for the UK, this has been signaled for a number of weeks now; a late June change. However, it still looks to me that any blocking regimes will be short-lived and a return to a more cyclonic pattern as we progress through July will return. The chances of this summer becoming anything special from a UK's perspective looks slimmer and slimmer by the day/week... Matt.
  7. Just a quick update with some thoughts... Starting with a short video of recent GFS 850mb ZWA plots, when viewed this way you can really get a better 'feel' for how the anoms are evolving (or not) and, to me, what remains of some concern is the continued -ve E'ly trades that are persistent particularly between the dateline and 120W. While there is clear evidence for the increased W'ly flow, to the west of this region of the Pacific, especially seeing now that the MJO has most certainly progressed into P4 and soon into P5, is this likely to end up being a failed attempt at reversing the more recent Nina profile than when compared with the likes of the major MJO/WWB of May(?) While my experience here is lacking, which doesn't help with regards to using previous patterns and similar evolutions as a backdrop, I'm beginning to get the feeling that despite this likely having some influence on the AAM, potentially bringing a rise and perhaps also getting the GWO out of COD, which it is nearly in, albeit on the more 'nino side', could this well be the 'point of no return' for a more well established Nina profile(?) - The GEFS has been verifiying well, with regards to the MJO anoms. The OLR MJO CA model, along with the GEFS clearly shows the established -ve values through the WPAC at the moment and over the next 7 to 10 days. However, I've been saving this charts as well, when I can, as often as I can and what stands out within the last few days is the signal for a pronounced region of +ve OLR values and a clear region of supression to return to the I/O and, perhaps, eventually the WPAC. The other feature of interest clearly continues to be the +ve OLR values over the EPAC, presumably in relation to the heightened risk of E'lies and the trades within that region, especially to the east of 120W. Only source for ECMWF versions of all this is what is put on Twitter by Ventrice from time-to-time, but the latest GFS 850mb ZWA plots do look more like those ECMWF charts he has posted. Clearly, models are just that, models and can and do change, but like various areas of meteorology, what I feel is extremely important with regards to this particular area of meteorology (MJO, AAM, GSDM et al) is consistency and sustained trends. That is why I'm making extra effort to save these images, locally, to help build up a better 'picture' of evolution. Just logging on and looking at one run, to me, isn't going to be of much use really apart from just discussing what that particular run is showing. There's plenty of room for improvement here, model output wise as well if anyone is a whizz at programming and model production! From a UK's perspective a change is needed, whether sustained or not. Clearly, the massive Greenland/polar blocking is on it's way out and, overall, there is evidence in NWP now for a greater risk of blocking to make an appearance by the end of the month. So my latest prediction would be that this MJO/WWB would likely have some influence on the Pacific jet, hopefully (not that I'm 100% sure of how and why) but likely bring a risk of an EAMT, perhaps a NAMT and, overall, see a general increase in W'ly momentum through the tropics and provide, perhaps temporarily, a more Nino profile, especially when compared with the last 7 to 14 days. However, it does seem that there is some element of a 'point of no return here'. I've been a meteorologist for over a decade and I would hope that would still provide me with some techniques and guidance here, and using an analogy, of sorts, it sort of seems increasingly to me that this is like a steam engine that is slowly running out of fuel and, clearly, that relates to the more Nino profile through the Pacific, especially so once this current MJO activity has eased. Clearly, if that is indeed the case then from a summer perspective the best the UK/NW Europe would likely hope for are temporary ridges, transient spells of warmth from the S or SW as the pattern remains relatively mobile and, most likely, more cyclonic than not. Quite incredible we are, already, approaching the longest day... A fascinating watch continues, but is the current MJO activity just, eventually at least, delaying the inevitable now?... Kind regards to all, Matt.
  8. Just a quick reply, but definitely progressing in the 'right' direction with regards to the MJO getting into the W Pacific. I've started saving some charts to help consistency which aren't archived from their parent site, and the following three 850mb wind anoms are quite telling with regards to the steady increase in W'ly flow, especially around and to the east of 120E, just to the west of the dateline on today's update. It's a shame these images aren't archive as this really does help to view any consistency that may (or may not) be developnig. I will be saving this as often as I can... The other two images, based on the CA and the GEFS which 'stood out' as well are as follows... MJO P4-5 seems on the cards to me and, hopefully, with AAM implications within the next 7 to 14 days. Downstream influences perhaps around and beyond the weekend of the 22nd and the 23rd of June for the UK...we shall see. Matt.
  9. Hi, just a few latest thoughts as the situation becomes even more interesting and important for the second half of June and into early July... Just starting with the 00Z means from the EC, GFS and the CMC. What seems to stand out here is a pattern which may well be connected/related to the increase in W'ly momentum and an up-tick/spike in AAM looking forward. The Pacific is starting to exhibit more of a troughed pattern, while the extensive Greenland blocking and higher heights within the N Atlantic are on the way out as well, we clearly see a more pronounced signal for an Atlantic trough. Despite 'confusion' could NWP be picking up on the potential pattern changes that would arise as a result of the MJO/WWB activity?...time will tell, but clearly there remains a distinct split in model output regarding the activity of the MJO, but, to me the N Hem pattern is showing signs of changing. Within the last 7 days, overall, both the GEFS and the CA output, from the MJO have verified well after many models failing to capture the progression through a higher I/O/P2-P3 phase. One could argue that the CA 'model' was too progressive into phase 4 with a likely fall in the amplification now through phase 3, but that still does mean the MJO has progressed through the I/O with reasonable vigour. Where we go from there though still seems to be uncertain... While I don't wish to get bogged down too much with the RMM plots, they do, at the moment, highlight the variation well with regards to whether the MJO progresses into P4-P5 (maritimes) with reasonable amplification or whether it is far less significant. The CFS has been very consistent with this signal, while the GEFS has also increased the amplification with a 'strong' P4-P5 transition over the next 7 to 10 days. This is, however, counterbalanced by the ECM and the EC Monthly, along with the CA model too, which is far more muted despite still heading in that direction. The CA model in particular really has 'flipped' over the last day or so, as I've been keeping track of this most days, with now even a reversal of the OLR output by days 11-15 through the I/O and just about into the Maritimes - https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml - The CFS in particular remains the most significant with regards to the MJO development through the Pacific over the next 2 weeks. One could argue that it is likely too progressive, but that being said the consistency is very interesting and even if it isn't as active as is suggested, it would still likely mean a progression into the important P4-P5 phases. It's not a surprise that the CFS plot on Victor's site is 'off the scale' when looking at the 200 VP anoms, especially for the period 17th to the 23rd of June, that would no doubt lead to a marked increase in W'ly momentum and signal that rise in AAM which, in theory, would reverse the Pacific pattern to a more troughed regime, thus then influencing the downstream patterns over the US and into the N Atlantic. Again, that seems too extreme to me, but that aside, the consistency for this rise continues. As a counterbalance to the above the below 850mb ZWA's aren't particularly inspiring and certainly wouldn't represent a transition back to a W'ly dominated Pacific pattern. Of course this is just one run of the GFS Op (left) but that really is a solid region of E'ly anoms especially around and to the east of the dateline, despite the obvious increase in W'lies west of 120E in association with the MJO activity. The ECM EPS (grabbed from Ventrice on Twitter and sent to me by Tamara too) isn't great either by the looks either with a clear E'ly anom, again, east of the dateline and with little W'ly activity trying to counteract that. Perhaps the overall outcome will be that of a 'middle ground' with the CFS being far too progressive with the MJO activity, while the likes of the ECM potentially not significant enough. I still believe that compared with of late and over the last 7 to 14 days there will be some reduction in the trades as this MJO activity develops and, hopefully, we see an increase in AAM and, overall, help to modify the N Hem pattern so we break out of this Atlantic ridge and UK/NW European trough. Clearly this would also influence the US pattern too which seems to have seen a particularly cool and unsettled late spring/early summer too, especially across the E and NE, that perhaps also linked back into the particularly -NAO regime as well and the Greenland blocking pattern. What I do find interesting as well, yet also something of a 'chicken and the egg' scenario with all this is that while signals do indeed lead models (thanks Tamara!) we are still using models here to see how the signals will progress...There is no other way, not that I know off, to gauge how the MJO et al will evolve and how that may well that influence the likes of the AAM, SST's without looking at model output, but if the signals are leading the models, then, again, a 'chicken and egg' situation comes to mind. That aside, this is a fascinating watch, more so as the knowledge and connections come together (thanks again Tamara!) - From a UK's perspective half of June is done with, some improvement, IMO, is likely through the second half of the month, one could argue that things could only get better from the situation at the moment anyway, but I still expect/predict that changes will come, whether they are sustained or not is another story. Even if this MJO activity does play through the system and has some influence there would still then likely be a return to a surpression phase, through the Pacific perhaps into July, CFS shows that as a possibility on the plot above through July 1st to 7th. With the SST's as well 'playing silly buggers' with lowering SST anoms both over the east and west Pacific and possible Modoki patterns evolving then this summer could well be one of highs and lows, but I have a feeling now there'll be more 'lows' than 'highs' - pun intended! Kind regards to all, Matt.
  10. Hi all, just another general post with thoughts and discussions as things stand... All eyes continue to be on the development of the MJO activity through the I/O and, potentially, into the Maritimes in the next week or so. The last 7 to 10 days has, without question seen a more Nina profile present, despite the broader pattern still remaining Nino, this being exampled well on the on-going Total AAM plots, with +AAM regime continuing. What is of interest, however, is the evidence for the MJO to be more robust than most models knew about a week or so ago. This is example well on the below plots, using the GEFS BC RMM plot. Clearly note the signal from the 29th of May for the activity to die away before it really got out of P2. However, in reality, the opening few days of June clearly produced a far more noteworthy progression into P3 with reasonable amplification as well. This is obviously using the GEFS BC plot, but others were/are similar. Some interesting 'goings on' short term now as to where we go, but certainly some evidence to get the MJO into the important P4-P5 phases. It is still unlikely though that this MJO event will be as noteworthy as the one from back in May. The current state plots highlight the situation well. Despite the usual few days lag, there may well already be some evidence within the GSDM for this MJO to be having some influence. The 4th June update clearly shows that the E'ly momentum through 30N-40N is waning, while there has been an uptick in AAM. Of importance though is the AAM Tendency plot, note the recent rise. The other thing to note as well on the Total AAM plot is the persistent +ve AAM regime. This reinforces the signal that, overall, the atmosphere remains pre-conditioned for an El Nino profile, not La Nina, so the atmosphere is ready to 'link up' to the ocean, across the Pacific, if this MJO activity propagates eastwards. The SST anoms need to be watched closely as well as while there is seemingly some evidence to suggest that cooling is/has taken place both across the eastern and western Pacific in association with on-going upwelling and downwelling events. The below NOAA plot does highlight that to an extent with clearly the focus for the most significant warmth being around the dateline. Could we be progressing towards a possible Modoki El Nino moving forward (?) - One to keep an eye on. Looking forward and, from a UK perspective, the hope would be for a renewed spike in AAM as the current MJO/WWB plays through the system. However, as has been alluded too in the last week or more, the E'ly flow needs to be overcome and with current 850mb ZW anoms in the order of -6 to -9 ms then that's quite a 'brick wall' any W'ly flow will be running in to. The split in model data doesn't help still either with the CFS still particularly bullish with regards to a fairly active MJO wave and with a standing wave that remains within the Pacific deep in June. The consistency within the AAM plot from Victor's site remains and, in fact, if anything the last few updates has increased the signal for AAM to rise towards and beyond the middle of the month. The pronounced Atlantic Ridge - UK/NW Europe trough pattern remains a problem and I can't see that going anywhere just yet, or not before mid-month anyway. The other aspect which I believe is a 'wildcard' is the continued and extensive N Blocking http://mp1.met.psu.edu/~fxg1/CMCNA_0z/test8.gif ) over the N Atlantic and around Greenland. The usual NAO and AO plots from the NOAA site ( https://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.sprd2.gif ) also continue to highlight well just how persistently -ve both the AO and especially the NAO has been. In theory, this legacy from the final warming should wane, eventually (hopefully!) but unless I can be advised otherwise I think the persistence of this blocking regime has lasted longer than many/all would think have been the case and this, at times, has clearly been overriding any Pacific signals to me. The dreaded year of 2012 was dominated by this pattern over the N Atlantic and Greenland and it was known here in the UK as the 'year without a summer'. Hopefully, that semi-permanent feature will eventually decline too. So, the wait goes on to see whether the likes of the persistent CFS will come to fruition, progressing the MJO into the Pacific with an increase in W'ly flow and a reduction in the trades, or whether it dies'a death over the Maritimes and the trades 'rule the roost'. It'll be an interesting watch but "nailing my colours to the mast" and my prediction is that this MJO event will have an influence and with, eventually, a return to a more 'complete' Nino profile will arrive during mid-to-late June with resultant synoptic changes....but we shall see! Kind regards to all, Matt.
  11. Quick Sunday update with a few thoughts and graphics.... An unsettled week ahead for the UK with a pronounced trough over NW Europe set to bring a rather poor start to June. However, all eyes are still on the next MJO wave which is currently through the I/O and it still looks like it is forecast to progress into Maritimes/W Pacific. The increase in the trade (E'ly) winds through the Pacific has definitely created more of a Nina profile to the atmosphere, at the moment, but still with what is a primary Nino 'base state'. However, there is no surprise then that the N Atlantic has got the Atlantic Ridge - UK Trough pattern fairly locked in. The main question is will this MJO activity create enough of a WWB to counteract the E'lies to increase W'ly momentum through the tropics and to increase AAM as, rather crudely, predicted below. The prediction, to me, looking ahead towards mid-June would be for the E'ly momentum near 20N-30N to be replaced by W'ly momentum and, in turn, influence the Pacific jet to create a more Nino profile. This would, in theory, pull everything westwards and, eventually, mean that the Atlantic pattern would be dominated by a trough and the UK would then see a downstream ridge with possible Azores extension NE. Interestingly the 00Z EC is doing that even by the 11th/12th but that could be a bit on the early side but that is what we need to look for further down the line now to get out of this cyclonic start to summer. The AAM CFS charts from Victors site remains consistent with the rise in AAM through towards mid-June, even though there has been a few 'wobbles' in recent days. The highly useful archive of 30-day data, however, really does tell the persistent story of a rise in AAM from the main 4 members that make up that particular graphic/ENS. Clearly, there is other model data which isn't as optimistic with such a rise, but from feedback and information in recent weeks, this data is certainly of worth, especially when it is showing the consistency it is showing. The other graphic of interest, more related to the short-term is the TRITON SST and Wind chart too. When compared with the same graphic I posted the other day, the means in particularly have certainly become far more variable, with the W'ly signal being lost, overall, especially through the central Pacific. Again this seems to tie in nicely with the lack of convective activity and the increased amount of divergence at lower levels through the Pacific in the wake of the MJO/WWB from a few weeks back, allowing for an increase in the trades. All eyes on this next MJO wave in the next 7 to 10 days, from a UK's perspective, here's hoping it has some influence and the forecast model data for a rise/spike in AAM develops creating that return to more of a Nino profile as was the case through much of May! Kind regards, Matt.
  12. Hi. Some latest thoughts and analysis, as usual, there is a bias/focus on how this may influence the UK's weather and the N Atlantic/European domain than the USA, but, still hopefully of some interest and worth. As usual, any obvious errors in analysis please do let me know, the learning curve continues and apologies if, at times, I'm sounding things out which are obvious but, again, it helps with the understanding and analysis. OVERVIEW: A general increase in E'ly momentum through the sub-tropics, especially around 30N, is a primary change since the last update. This is being balanced out by some evidence for increased W'ly momentum through the mid-lats and, therefore, is likely aiding in this more cyclonic spell of weather now (for the UK) and also looking ahead into the opening week of June. Looking further ahead and attention remains drawn to whether additional MJO activity can maintain the more Nino pattern through the Pacific as we progress further into early summer. Compared with a few weeks ago, the risk of this Nino pattern breaking down or, at a minimum, weakening has increased IMO and this maintains a long-standing summary and prediction that this summer will not mirror that of last summer (for the UK) in any way, with a far more varied and, at times, volatile synoptic evolution. ANALYSIS: Since the last MJO event of mid-May there has been little MJO/Kelvin wave activity through the tropical Pacific with the MJO activity residing through the Western Hemisphere and soon to be within the Indian Ocen (I/O). This lack of MJO activity through the Pacific has most certainly meant that the significant WWB (Westerly Wind Burst) of mid-May, with increased W'ly flow has been replaced by a greater propensity for E'ly winds and an increase in the trade winds through the Pacific, especially through to the dateline. The net result is, overall, for an increase in E'ly momentum through the sub-tropics on the AAM plot even though, overall, AAM remains positive. This, within the short term, is most certainly aiding in producing the more cyclonic period of weather across NW Europe with the broader pattern being of one that is more Nina-like (Atlantic Ridge, UK Trough) than Nino (Atlantic trough, UK Ridge) and will likely do so through the opening week of June. This setup is exampled perfectly on the GFS, ECM and CMC anom plots below as well. That pattern certainly doesn't represent a Nino/+AAM profile and is a pattern which clearly isn't good news from a UK's perspective for summer-like weather. The other thing to note as well are the continued signal for northern/polar blocking too, that may yet still have some influence on the summer. If it remains a feature then this may well maintain a threat of more S'ly tracking jet patterns at times (-AO/-NAO regimes), increasing the risk of possible cyclonic interludes. The continued lack of sea ice ( https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/) over the pole, especially from 2010 onwards, remains a major wildcard at the moment and, personally, I believe we don't yet fully understand the impacts of the lack of sea ice there now on the climate and synoptics of the N Hem, but that's another topic of discussion! The graphic below, from the 28th, highlights the SST's and wind direction/speed well through the tropical Pacific, noting too that the general flow at the time of production of this chart was from an eastern quadrant and with a clear cooling of the SST's within the eastern region of the tropical Pacific, while the 5 day means, ending on the 28th, does still show a W'ly bias with slightly above average SST's, this highlighting that, overall, an El Nino pattern remains present albeit in a more weakened state than compared with a few weeks back. What remains important now is the introduction of additional convective activity in association with MJO activity through the I/O and into the western tropical Pacific. While there has been model divergence over the movement of this next MJO wave, it does look likely that, unlike the last event, this will not get beyond phase 3. This is exampled well on the below plots from the GEFS, ECM and EC Monthly. All three of those, amongst others, clearly bring a reasonably high amplitude MJO event into the I/O and, perhaps, just about into the western Pacific before the signal is lost as things stand. Whether this produces another significant WWB through the tropics to increase AAM once again to allow us to break out of this Atlantic ridge and UK trough pattern remains to be seen. Where we go from there is uncertain, even more so now that after this up-coming MJO wave there is uncertainty as to how it'll develop beyond that time frame. Some discussions suggest that there will not be enough MJO activity to sustain the Nino standing wave through the Pacific this summer and the trades may well 'win out' meaning, at least, a neutral pattern may develop, possibly a Modoki El Nino where the highest SST's are focused within the mid-tropical-Pacific, flanked by cooler, more -ve SST anoms. The longer range CFS data does maintain -ve 200VP anoms through the Pacific by late June, implying that there will continue to be further WWB and MJO activity. However, the spread in the ENS output for the AAM after mid-June is now increasingly large after being focused around a trend toward >2sd AAM values in recent days and weeks. This introduction of spread increases the uncertainty further as to whether another surge in AAM will occur or not. Finally and while I can't take credit for picking this out (@griteater on twitter posted the images) the other fascinating link since February to May is indeed this Nino/+AAM signal which has dominated, overall, over the last 4 months. Note the strong negative VP200 signals within the Pacific, indicating active MJO activity and significant WWB activity. The resultant 500mb pattern matches that very well, with an upstream trough within the N Atlantic, but with a downstream ridge over the UK, everything pulled westwards/upstream as compared with what is likely on the way over the next 7 to 10 days. This links in well with the particularly dry weather (for the UK) in recent months too, but that pattern is clearly at odds with what is being forecast at the moment. It remains to be seen whether this pattern can be maintained this summer if it can then heat and humidity will never be too far away, but with short-lived breakdowns, if it can't then a more cyclonic outlook, overall, for the UK may well be on the way this summer. SUMMARY: Cyclonic pattern now dominates through to at least the end of the first week of June in association with an increase in W'ly momentum through the mid-lats. All eyes on the next MJO development through the I/O in the coming days and (perhaps) into the W Pacific thereafter; will it re-introduce another WWB of significance. Maintain a close eye on Pacific SST's to watch for continued cooling over the eastern tropical Pacific, perhaps in the west too (Modoki El Nino pattern developing?). A potential transition towards a warmer and more anticyclonic spell may arrive towards mid-June once this next MJO activity plays through the system. Latest prediction for June now is for a 'typically British' early summer month with both temporary warmth and dry weather interspersed with cooler/cyclonic spells. Regards to all, Matt.
  13. Quick one today and thanks for that... Have to agree there. The rather persistent theme of some of the US forecasters for the Nino pattern to break down has seemed rather extreme to me. Mike Ventrice in particular seems very keen on removing the pattern in the coming weeks but that seems very premature to me. There continues to be evidence for a renewed MJO event into the I/O in the next week but confidence does drop away after that as to whether it makes it into the Pacific and also the 'intensity' of it too by that point. At a minimum it's likely to maintain some counterbalance to any increase in E'ly flow. Where we go from there is very uncertain mind. The CFS AAM plots on Victors site haven't wavered and maintain a clear trend towards a significant +AAM state, as shown below, one could argue a few of the members in the latest run are OTT but it's been very consistent.
  14. Hi Isotherm, thanks for that, interesting read. However, just want to flesh out some details on one point you make, which I quote below; "However, recent weeks have seen increasingly negative frictional torque, negative EA MT, which will be reflected in an AAM decline, to a certain extent." However, as I believe it, should the -ve FT not be increasing angular momentum? - This would tie in well with the plots of recent months (see below) in which has seen FT clearly negative for large portions of it, but with, overall, significant amounts of +AAM, especially through the sub-tropics but, temporarily, at more northern latitudes too. Clearly, however, this general +AAM trend continues to be related to a more Nino atmospheric profile which has, at times, continued to promote several northern blocking regimes across the N Atlantic and UK domain, noticeably at present and through large portions of April which were, obviously, in association with increased E'ly momentum through the mid-lats. This was, however, interspersed with more W'ly regimes through late April, which brought a more cyclonic early May profile and, noticeably during early March, but that was also linked to the potent strat vortex too. Just one piece of information, gained in recent months which discusses both variables below and as I have thought is the way things work. "If there is a net global surface westerly wind, the atmosphere will speed up the earth’s rotation (positive FT), transfer angular momentum to the earth and the atmosphere loses angular momentum. If there is a net easterly surface wind, the atmosphere slows down the earth’s rotation (negative FT) and the atmosphere gains angular momentum" Please do correct me if I'm wrong here, but certainly, hope I'm not! Regards, Matt.
  15. End of the week post...apologies if any typo's/grammar issues, been a long week and an early work start this morning...a cold beer awaits! So, where are we now? Without sounding like a stuck record, the significant MJO development from a week or two back most certainly aided in producing a significant WWB and of which aided in reversing the AAM at the mid-lats than compared with late April and into early May. This was well predicted in advance, pretty much 2 weeks back, at the end of April, that a shift away from the more changeable pattern (for the UK) would mean a much greater risk of blocking patterns, once again, and amplification to the pattern. The overall AAM plots haven't changed a great deal within the last week, but the transition to an increased amount of E'ly momentum through the mid-lats is in evidence, while clearly there's plenty of W'ly momentum through the tropics, the overall Nino pattern remains. The anom plot covering the 12th to the 15th of May really does highlight well the transition to significant amplification and a more blocked regime across NW Europe and this, yet again, continues to link up towards the extensive high pressure that remains dominant over polar regions in relation to the continued influences from the final warming of the strat vortex, now a number of weeks ago. What is quite impressive with the last month or so is how dynamic and 'active' this downwelling has been and certainly more influential and of significance than what followed the SSW in early January. Equally, just starting to look ahead but the CFS continues to highlight a potential return to a heightened risk of a convective atmosphere through the I/O and perhaps into the Pacific again through the first half of June, this exampled on the NCICS plot. Note as well, the significant MJO activity from late April and into early May too which continues to link well with the above transition of the AAM Where do we go from here? Well, to be honest, through the final 10 to 14 days of May, I'm not entirely sure. NWP has been all over the place this week with regards to the UK and the patterns across the N Atlantic. At times, finally showing a breakdown of the blocking regimes at more polar regions, perhaps signaling an end to the downwelling event. However, that signal soon reversed and northern blocking at latitudes where you don't really want it at this time of year does look set to continue. While the recent links between the MJO/WWB event and transition to increased E'ly momentum at higher latitudes have definitely had an effect on the patterns to date, I'm not entirely sure whether this influence will now wane through the rest of the month, it seems like it to me now, with blocking patterns becoming less likely at say 45-60N. The other important signal now is increased consistency for a more cyclonic pattern to evolve across the N Atlantic and into NW Europe looking ahead, this all coming 'underneath' yet further blocking over Greenland. I have a feeling that until this unwanted blocking clears off, then we won't default into a more typical 'summertime pattern'. The 00Z ECMWF highlights this well, amongst other models too; The persistence of this block really is painful to see and watch, from a cold/winter fans point of view. We've had an alternating Scandinavian-Greenland blocking pattern now for what feels like weeks, it probably has been weeks and, again, until this blocking regime breaks down then the outlook is particularly uncertain. However, what is somewhat confusing is the ability to still get fairly mobile and W'ly weather across the N Atlantic under this blocking looking ahead, despite what has been a clear transition to a heightened E'ly momentum at higher latitudes. Given some guidance from Tamara regarding the below image, the CFS outlook has and continues to signal a marked rise in AAM through towards the middle of June and, in fact, the last few model runs has taken this signal to >2sd from the main 4 members. The obvious question here is: Is the CFS just simply over doing this signal or, is it correctly picking up on yet further MJO activity running through the I/O and into the Pacific to reinforce the westerly momentum and keep the overall Nino pattern going looking ahead and this increasing the changes of heightened E'ly momentum through the mid-lats? Another final piece to the puzzle is regarding some tweets I have seen with regards to the actual fall in SST anoms across more central and eastern areas of the Pacific in recent days, despite the recent significant WWB/CCKW activity. Some are now suggesting a possible trend away from a more Nino type, to perhaps La Nina looking ahead, no doubt this is unlikely to be of any great significance within the short term, but could perhaps have greater influences on the longer term, through the latter stages of the summer. However, there seems to be uncertainty and discussion regarding this with various posts and graphics showing both sides of the coin and I also recently spotted this tweet from Paul Roundy; So, in summary.... 1)The blocking regimes of present can clearly be connected back to the MJO activity of past weeks and the increased W'ly momentum through the sub-tropics and a reverse through the mid-lats. 2) Northern (Greenland) blocking continues to be a troublesome feature and despite the recent developments still seems to be a feature looking ahead and this may well maintain a more cyclonic pattern to the N Atlantic, beneath the blocking through the rest of May. 3) All eyes on the potential for further MJO activity through the I/O into early June and this possible signal from the CFS to increase AAM as the opening summer month progresses as this could well then have sig impacts for summer weather down the line. Cheers and have a good weekend, Matt.
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