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Showing content with the highest reputation since 21/05/18 in Posts

  1. 28 points
    The first and most important thing to say is to enjoy the spoils of some excellent weather in the 7 to 10 day period. After a warm week ahead, it could feel quite tropical by the Bank Holiday weekend with hot sunshine for many and some thundery downpours for some....then clearing to let hot sunshine out again. Rinse and repeat for a few days The last post gave some background as to how the early season warm spells have evolved since mid April. The highlighted sections of the above extracts from that post last week then went on to try to anticipate a likely crossroads ahead. This crossroads now broken down into basic suggested pathway scenarios : Changing seasonal wavelengths from Spring to Summer > leading to either, Low atmospheric angular momentum retrogression of the wavelength - North Atlantic/Greenland ridge and downstream trough or, High(er) angular momentum greater retention of downstream Scandinavian/European ridging and a troughing profile in the Atlantic to our west or, There is actually a third scenario that involves a lapse around the 12 to 15 day period into the Option 1 but a bounce (and likely a sustained cyclical bounce) back to Option 2 thereafter. That is I freely admit, covering all options *and sounding like a lot of back covering on her part* but two things here: The aim is, and has never been to give long range predictive forecasts - there are plenty of guru's around who like to do that anyway without adding any more. Secondly, the balance of factors, as I see them, are very finely balanced, so it seems eminently sensible to pitch any summary suggestions to embrace all the spectre of possibilities within that envelope. So I have my own little ensemble suite most of the time, which seems to work for me anyway Speaking of ensembles, NWP has indeed started to take the suggested pathways under the radar as we start the new week. The retrogression spectre started to appear in some low resolution GFS output late last week and now the EPS clusters have started to pick up on this signal. However, the background signals in relation to the tropics, extra tropics and subsequent consequences for atmospheric angular momentum remain uncertain. Based on some more recent historical precedence (and also a seemingly increasingly inherent longer term climate trend, but that is not for this thread) it would be easy to see start of summer and yet another collapsing angular momentum regime as somewhat predictable with a string of summers in the last 10 yrs following this same pattern.... Spring warmth leading to another indifferent cool and damp summer.... But back to basics - where are we with things this since time last week? GLAAM has slumped back below average, losing the gains of the recovery earned since mid April However, as likely commented to be the case last week, relative angular momentum tendency has been holding higher again in the present low cycle ebb than the previous low tide marks in the global wind-flow cycles of mid March and then early April. The inference of this, extrapolated longer term, is that the atmosphere is trying to resurrect itself longer term from the La Nina state that has, mostly, been in evidence for the last two years. Convection in the tropics in reflection of this, is continuing to imprint the active periodicity (recurrence) cycle of the last 90 days. As bolded in the captioned post above, what is very important as we hit June is that we see clear signals that MJO forcing wants to embrace eastward shift to the Pacific as represented by an evolution to Phases 6,7 and 8. This, as demonstration that the upcoming cycle represents a further move away from La Nina with accelerating westerly wind inertia in the atmospheric circulation sustaining the priming of downstream summer warm ridges rather than sustained lapse into downstream summer chilly trough. The deterministic tropical convection forecasts have been proving, not unusually, a bit too progressive with trying to break down amplitude of the latest cycle. There is a conceivable chance this time around that modelling may overcook -ve AAM downside, and hence any blocking in the North Atlantic and/or Greenland may be overblown. Either that, or of it does verify, it does not sustain. Just this side of the Spring/Summer wavelength changes, in the short term the recent fall back of AAM has done no harm at all. Indeed, the upstream deceleration of the jet has/is helping our downstream ridge hold sway with a moribund Atlantic. The deceleration and amplification of the jet upstream in the Pacific clearly represented here by the -ve mountain torque over Asia - with the consequent vacuum created to fill as momentum is lost from atmospheric wind-flows Such a negative AAM regime, however, not recovering as we arrive at imminent changing seasonal wavelengths also assists further retrogression of the longwave pattern and is not desirable longer term. So its important that momentum upstream has some impetus heading into the new month so that any retrogressed ridge to the W or NW (should it evolve) is shunted back east by the jet stream increasing from upstream and as a consequence LP being re-set in the Atlantic. This scenario would suggest a pre-cursor to some further, sustained warmth into the meat and bones of official summer - even if the initial burst of momemtum flattens the ridging initially and allows a (likely brief) more unsettled westerly pattern for a time. Some of our best summers have displayed this sequence of events in early season, so the retrogression scenario of the extended period, should it come about, should not be treated as "summer is over before its officially begun" . It could well prove to be the opposite. On that basis, the present and upcoming spell of weather may well be just a taste of what is to come. So best not fret, just yet anyway, about the new month (and new season) breaking the weather down - it might not be for too long if it does happen Have a lovely week and Bank Holiday weekend
  2. 23 points
    ...and so it has been proving to be the case Extended NWP attempted suggestions of retrogression of the pattern have been adjusting continually backwards over the last 10 days as updated atmospheric angular momentum tendency plots have kept showing a steady upward trending. As a result, the increasingly warm European pattern has been steadily extending in longevity Stripping away the longer term -ve AAM biases, then adjusted model plots show a continuation of this buoyant trend through , at the least, the opening 10 days of June The continued active periodicity (recurrence cycle) of tropical convection of several months has confirmed suspicions that deterministic MJO models would persist in undercooking eastward progression and amplitude of progression of tropical thunderstorm activity, and their associated westerly wind bursts that drive the rossby wave trains that develop downstream amplification and carve out anticyclones - and hence overestimate downside of AAM tendency. Anything beyond 4/5 days on these plots is subject to work in progress - amplitude has been continually revised upwards through this present cycle Hence the work in progress adjustments that have percolated into NWP to keep the downstream ridging stronger for longer, and put back the retrogression of the pattern and suppression southwards of the Jetstream. Taking into account these atmospheric circulation trends, then the evolution of the cycle in June, is closely related to the seasonal wavelength changes into summer, and will continue to be tied into an active tropics to keeping a warm pattern sustained. Of course, the cycle wanes as well as waxes, so at some stage there will be a backward adjustment (probably tied into the latter stages of the current tropical cycle once it has arrived in the Pacific) but what will be important if/when any less warm and settled interlude arrives will be the measure of how much higher the next lull phase in the tropics and extra tropics is compared to earlier in May. So, for once, we are coming into early summer with the atmospheric cycle pre-disposed towards downstream summer ridges - rather than seeing momentum collapse as it has done in years like 2007 and 2011. There is little point, in my opinion, of over dwelling on the winners and losers of a start of season pattern that is bound to have lag restrictions hung over from an extended cold season up to mid April at least. This is an island, and nothing is going to change that. Relatively cold seas are bound to make differences and cause issues such as low cloud and mist particularly on windward coasts, and especially added on to the detritus from thunderstorm activity from a nearby continent that is, self evidently, land-locked and therefore subject to much more rapid diurnal heating sooner that the UK This is as good a start as any could realistically hope for and every chance that future warm spells might build on the intensity of the current ones. Upper cold pooling to our west and south west and heat ridging in all vectors to our east is the broad-scale pattern that our best summers are built on and can be very sustained.
  3. 21 points
    130 photos taken this evening. Have attached the ones I consider decent enough to share. Apologies for some of the scratches and marks on the pictures; my camera body needs a damn good clean. The last one is my personal favourite.
  4. 20 points
    Please forgive me, I have no knowledge of the weather, I've only been on here for 13 years but the Ecm 12z shows charts that some people might like!...
  5. 18 points
    Hi guys, First post here. Hope you enjoy. Here's the view in Brighton looking south east a moment ago. No processing/filtering on this image either.
  6. 18 points
    This is a director at STV who spent the weekend down south, away from the haar and 11C max of edinburgh, to capture ...
  7. 17 points
    Risk of storms developing later for southern counties of England, especially overnight, my storm forecast: Storm & Convective Forecast Issued 2018-05-23 11:22:02 Valid: 23/05/2018 0600z - 24/05/2018 0600z UK & IRELAND THUNDERSTORM FORECAST - 24 HOUR OUTLOOK Synopsis An upper level ridge extends NE across the NE Atlantic / Ireland and Scotland on Wednesday, with a weak and diffuse upper low over France. At the surface, a high will be centred close to Norway while further south a slack area of low pressure will cover much of mainland Europe. An increasingly warm/moist but unstable airmass aloft will spread west out of the near continent later today and overnight into Thursday, supporting an increasing risk of elevated heavy showers or thunderstorms across southern areas of England and later south Wales. ... S ENGLAND and S WALES ... Plume of increasingly steep lapse rates spreading W/NW out of near continent will, with diurnal heating, is indicated to yield 200-500 j/kg CAPE this afternoon across southern coastal counties of England. Although airmass will remain generally capped to convection, models hint at some showers or even a few isolated thunderstorms developing towards the south coast by early evening, before moving out into the Channel. Isolated incidences of hail and localised flooding are possible with any storms that develop. Then overnight, mid-level instability is expected to increase westwards across southern England from the near continent, as an elevated warm and moist plume of air undergoes isentropic lift as it rides W/NW atop cooler/drier NEly flow at the surface, the concurrent steepening of mid-level lapse rates will support an increase of elevated convection with a risk of scattered thunderstorms developing and spreading west across some southern counties of England overnight, perhaps reaching south Wales by the end of the night. Some of these storms may produce hail, frequent cloud-to-ground lightning and locally heavy rainfall rates that may lead to surface water flooding.
  8. 16 points
  9. 15 points
    just saw the latest met office forecast so I just told the missus to not be alarmed but there could be the odd flash and a few bangs later on tonight....she just laughed and said...."at your age and in your shape?.....I don't think so!"........*sigh*
  10. 15 points
    Well what a night for me!!!! Lol. So glad I made that trip down from Wrexham to see that storm. It was absolutely AWESOME! My hubby loved it too. I went out at the beginning of the storm and was running up and down the southern perimeter of Heathrow filming it then the rain came. So I dashed under the cover of the hotels underground parking and filmed it from there. Amazing. Watching 3 storms to the left, right and centre banging out constant lightning and constant rumbles of thunder. My little boy missed the first hour but when I went back to the room he woke up and was terrified. So I took him to the window and BOOM a massive fork across the sky and he shouted “WOWWWWW mummy that was AWESOME!!” So off outside we all went again and spent another hour watching it. He is now not afraid of storms and wanting more today Hahahaha. Just fabulous (not that you can tell ;-)) Haven’t watched the video properly yet. This is the only still I have that will let me post on here due to file size.
  11. 15 points
    A stunning end to ECM the high rebuilds and the warmth is spreading across Europe Long may it continue
  12. 14 points
    Going to write a little chase accout for Saturday on UKWW and also have pics from Sunday to edit but in the meantime, thought Id share a selection of photos from Saturday here. Definitely my most successful lightning photography to date!
  13. 14 points
    Looking down towards Arundel from Dunsfold
  14. 14 points
    What a fantastic week of weather up in the Northwest last week. Glad I made the visit to old haunts. The countryside looked stunning. Back in Sussex for a week and super warm down here and smells continental ( if you know what I mean ). Looks like the great early summer weather to continue looking at the latest models, especially in the North and West. I would imagine a lot of you seasoned weather watchers are rating 2018 very highly, you have had everything, blizzards, record March cold, heat and prolonged sunshine in May for many and a few impressive thunderstorms thrown in for good measure. Vintage stuff. Wonder if the North Atlantic has been ever so dormant ? Charts seem to show endless blocking so far this year. One more week in lovely Blighty then off to Benidorm for week of cheap beer and tapas! Enjoy the great weather. C
  15. 14 points
    Lovely stuff from the Ecm 00z and what a finish..stunning! Just another 4 months of this will do nicely
  16. 14 points
    Cracking storm around Birmingham earlier this morning
  17. 14 points
  18. 14 points
    As Frosty keeps showing, these unusual interesting charts keep cropping up this year, especially for the UK. Super cold in early March to super warm through much of May. The easily controlled Atlantic for much 2018 is certainly putting much of the British Isles in a Continental type regime ! (SO FAR ) but I think the majority on here , love it . Certainly enjoying the weather , especially up north on my visit to UK and not be subjected to endless days of wind blowing off the North Atlantic. A return to Sussex this weekend and more heat and a thunderstorm thrown in for good measure. Like being back in Austria! C
  19. 14 points
    The Ecm 12z shows classic summery weather as we import very warm / humid continental air across the uk from later this weekend and most of next week with sunny periods and an increasing risk of thunderstorms, at least across the south and in any decent sunshine with uppers like these i would expect temperatures into the mid / high 20's celsius across southern uk day after day, maybe into the low 30's c for a time in parts of the S / SE..what an incredible late spring this is turning into!
  20. 14 points
    In a nutshell for this morning, if an endless plume is not your thing, Look away now! Absolute convective paradise for the storm lovers, pretty much right throughout the entire run. What a year this could be shaping up to be, both for coldies earlier in March and for the thunderheads! Or even better if you’re like me and do both!
  21. 13 points
    What is going on in here?!? This thread is normally a friendly place where people who all share an interest of storms congregate. It is not a place for arguments! I have just got back in from work to catch up on the afternoons updates and feel like I have been transported into a creche. Come on, lets keep it friendly or posts will be disappear.
  22. 13 points
    So wow. What a day yesterday! Started out okay, as usual convection took it’s sweet little time to get going but by the time it finally did I had made it as far as the M40 junction with the A34 and had just decided to head back down towards London. Saw in my wing mirror an anvil spreading out and thought “I’ll check that on radar” Sure enough a couple of fresh sferics corresponded with the approx location of the cell, so I gave chase northwestwards. Within 25 mins driving the cell had fully burst into life and others were popping up too around it. Visually it was a bit of a mess, huge clouds all around couldn’t ascertain which was what - but I had essentially driven into a thunderstorm factory and it wasn’t moving in any particular direction any time soon! Found a perfect spot just north of Kenilworth, parked up and watched as the storms continued to grow... Storms were moving NWwards but lifespan was fairly short, however as new cells replaced them it essentially gave the impression of a very, very slow northerly track. It was just one long continuous rumble from where I was - the polar opposite to my experiences on Saturday where heavy rain high wind messed with any acoustics. In contrast - yesterday was relatively still with a gentle breeze and light convective showers - pretty good really! I could hear music wafting from behind distant trees. Considered this to be a local event, but then when I heard “Red Red Wine” being played I had a sudden realisation. Turned on Radio 2 to hear the same thing... and quickly realised I was only a short distance from BBCs Biggest Weekend in Coventry! Not everyday you get UB40 play live when you’re out chasing Back to the storms - could sense the lightning flashes from time to time, almost on the periphery, but knew closer to the cells there would have been quite frequent flashes - (mostly elevated as individual cells were tall and quite big) As cells began to track north I saw some CCs and CGs but they didn’t come out massively well in the photos as were infrequent and too far away. Also think I saw a LCL appear to my west toward Birmingham. Seemed to be scud moving about underneath, but was hard to see. Got a video anyway... One thing really got me was how huge the overshooting top was on the cluster of cells. Could see it in the distance and it was MASSIVE! Storms themselves were starting to dissipate a little though, so I decided enough was enough - time to head home and hopefully in time for a last orders pint at our local pub... Had a look at the radar and was astonished to see my route home was literally underneath in a 40 mile thunderstorm! Yesss! Turns out the convergence zone straddled the M40 / M1 - and it was kicking off big time! Chose the M1 option and at first could only see the distant thunderheads. Got a mile or two closer there were suddenly peripheral flashes - like I had crossed some sort of lightning boundary. Instantly - really frequent! There were no immediate turn-offs available so I stopped at Watford Gap to try to get some photos, but this cell was short-lived (despite the severity these were still pulse storms). All the way along the motorway it was fairly frequent flashes all around and the occasional CC fork. Then I got stuck as the carriageway appeared to have been closed for repairs. Saw some impatient idiots were trying to use the hard shoulder to bypass the queue which could have blocked the route for the emergency services (I’ll be honest part of me was tempted because I had storms to chase - but common sense prevailed) 25 min delay here which was significant later on as it made me miss the most mature stage of the Aylesbury monster anvil everyone in the south could see. Once the motorway reopened I drove as quickly as was safe to do so in the poor conditions (and battling with the 60% of drivers using lanes 2 to overtake all those non-existent lorries and vans, plus the 10% who are under the illusion that lane 3 is specifically for executive vehicles - come on ppl sort it out!) but I had a lot of ground to cover to get in front of the southernmost backbuilding cells. Eventually made it to Chorleywood (Dog Kennel Lane), clambered the small hill and faced the beast head on. Tripod quick! Camera quick! FLASH! FLASH! .... FLASH! .... ..... Flash! .... ..... ..... flash .... ... ... nothing. Aaaaagagh! Always happens! Mind you - if anyone had told me I would end the day’s chase racing a storm southwards toward the Guildford area I wouldn’t have believed you for a second just a shame I missed the chance to film or photo loads of those stunning anvil crawlers I could see as I passed Luton and Dunstable. Beautiful! IMO a far better storm than what i observed the previous night. It’s what we chasers like to see - conditions have to be right, clear skies making for good obs of high storm cells and thunderheads and slow motion of storms. Rain on Saturday was a real problem, but it was more confined yesterday to the cells themselves, and the wind was less gusty. Definitely a memorable day, just a shame I couldn’t get some really good photos in the end - but an awesome experience all the same Glad I decided to chase!
  23. 13 points
  24. 13 points
    Got this bad boy! Now going to start heading back up, and potentially intercept that potent one thats fired up over Clacton heading towards Cambs. What a night this is turning out to be!!
  25. 12 points
    Phew what a scorcher the Ecm 12z turns into and it's not even summer until T+252 hours..sensational charts for spring, especially when the winds go SEly / Sly!..very continental with plenty of very warm / hot sunny BBQ weather on this run!..a risk of T-storms at times too
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