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Everything posted by stodge

  1. Evening all I can imagine the end to the GFS 12Z OP will have got quite a few salivating - the classic stand off between the Scandinavian HP and the undercutting Atlantic trough - happy days. In the shorter term, it does look as though as the trough finally digs south to the east, we'll lose the balmy (or barmy) SW'lies and revert to a much cooler NW'ly flow for a few days. T+192 for the 12Z suite from GFS Control, OP, GEM and ECM The interplay between the Atlantic HP and the sub-tropical LP looks key to how this will play out. GEM creates a significant LP to the west of the Azores which means more of an Atlantic ridge and a more defined N'ly. Others keep the trough much closer in the North Sea - either way, it's much cooler and more unsettled than what we are currently enjoying. ECM ends with a lovely chilly November NE'ly - yes, I'm not convinced either.
  2. stodge


  3. Evening all Well now, of little import to the UK but this is a very cold run for Scandinavia and that's a decent little cold wave pushing through Finland and Sweden. Nearer to home, the heights to the NE promoting negative alignment of the trough sending LP ESE through the British Isles into Europe. Interesting to see if this trend continues or develops later in the month.
  4. Fair to say benign continues on the 12Z GFS OP - Control is rather more interesting if you fancy something colder from the north. GEM goes strongly unsettled - a return of Greenland heights by T+240. Plenty of options as you would expect - I wouldn't rule out a brief colder incursion which wouldn't be unusual and some early snow for the Scottish mountains.
  5. Lokað til austurs á Hellisheiði WWW.MBL.IS Lokað er til austurs á veginum um Hellisheiði um óákveðinn tíma vegna veðurs. Að sögn Vegagerðarinnar er ökumönnum bent á hjáleið um Þrengsli. A hint of winter perhaps....
  6. Evening all What I take from tonight's modelling is a progressive change to a more "traditional" and seasonal pattern as we move into and beyond the middle of the month. The extended period of LP over the Continent looks to be easing as, at long last, the Azores HP builds NE through France instead of being forced to the north of the British Isles. This may be due to more energy over Greenland (perhaps the result of ex-Hurricane Larry) which finally fires up the long-dormant jet forcing heights back just to the south as a more typical autumnal SW'ly sets up later in the month.
  7. Evening all I'm struggling to see much clarity as we move into September. ECM and GEM keep northern blocking which allows Atlantic LP to roll in to the British Isles on a southerly jet. GFS and JMA are much better keeping HP close to or over the British Isles - I'm interested to see GFS introducing ex-hurricanes though as always with these modelling their exact trajectories seems an inexact science at best. One seems to move NE, NW and then NE round the Azores HP - GFS Control has an ex-tropical feature moving in towards NW Europe.
  8. Evening all Again, just a quick glance at the evening output but the Greenland heights are hugely influential keeping the jet (as it is) to the south and suppressing any push of Azores HP. However, as you might expect, a lot of options on the table in the mid to long range - T+216 500s: ECM, JMA, GEM, GFS OP and GFS Control from the 12Z output. You pays your money....etc. We spoke about the possible breakdown the other evening - just some of the possibilities.
  9. Very true - up to a fortnight more of E'ly or NE'ly winds for downtown East London from the 12Z outputs - extraordinary for any time of year. Breakdown? Some thoughts - one possibility is from the south with the European LP encroaching north as the HP declines - the E'ly flows continues but becomes increasingly unstable. Another option (probably the favourite) is the HP sinks south, probably to the south west and allows Atlantic systems to encroach from the north-west. An outsider would be proper retrogression and a Scandinavian trough with LP moving down the North Sea bringing rain, showers and cool conditions. That's my three on first thoughts.
  10. Getting true retrogression is difficult enough any time of year, whether summer or winter. It's not just getting the heights in the right place - you also need the trough to drop nicely over Scandinavia to bring the N'ly down over the British Isles. Note the small LP over the Norwegian Sea which would extend SSW towards the North Sea as the HP retreated NW.
  11. Evening all Yes, a chilly NE'ly already present here in east London but it's a fine and glorious evening. It may not be full-fledged retrogression but with HP sitting to the north or north-west for a few days a steady ENE for most parts so, as they used to say, "go west" if you want the best of the weather but still decent further south and east. As to the longer term, as you might expect, the tendency is for the HP to slip back south or south west. No sign on GFS at any rate of any ex-hurricanes to bring some energy forward - GEM suggests otherwise.
  12. Evening all In contrast to many other late Augusts, not one to sit out in the north-facing back garden this evening. A distinctly chilly NE'ly setting up and I suspect we'll have it for several days in this part of the world. Fine and sunny and otherwise glorious - I suppose I could always sit in the front garden and mumble at people as they walk past......
  13. Evening all With this morning's Daily Star telling me it's going to be 31c by the end of the month, I'm looking for those +20 850s on this evening's charts. Let's see what we do have at T+216 in terms of 850s from this evening's 12z output. T+216 is Wednesday August 25th Respectively GFS OP, GFS Control, GEM, JMA and ECM Once again, GEM is the slight outlier keeping heat closer while all the others, frankly, don't. Now, let's not get carried away - the prevailing synoptic is to develop strong HP to the north of the British isles which means an E or NE flow so for the west it's going to be very good indeed with plenty of warm sunshine and hopefully any low cloud will burn back to the coasts early further east. It's what I call "San Diego" weather in reverse and frankly it's my favourite type of weather - low humidity, pleasant sunshine etc. I'd much prefer it to stifling heat and high humidity. GEM and to an extent JMA have more of an ESE so draws off warmer air with a short fetch across the cooler water. Entirely possible and oddly enough in midwinter, my favourite scenario for cold for the south east. Other models build the HP more to the north than north-east so the flow is more across the North Sea with a longer fetch. All in all, I like what I'm seeing tonight - if GFS in particular verifies, it's going to be very amenable weather. Glancing out to the end of the month for a bit of fun GFS OP and Control at T+360. One of the things I've observed this summer has been the persistence of LP over North Africa feeding into southern Europe. This has left heights further north than normal and has left Europe and southern Britain facing more thundery outbreaks. If you were to posit a shift of synoptic patterns north in response to a warmer world, this might be what you would see. The heat build up over North Africa manifests with heat LP as we see over desert southern California and pre-monsoon India. The HP response is to sit further north or west - it's most evident on GFS Control when the LP waxes north and creates instability over western and north western Europe - the outcome is heat and storms. You see the same in Southern California, Nevada and Arizona when humid unstable air moves up from Mexico - heat and storms. This is aided and abetted by a moribund Atlantic and a lack of energy to move the synoptic pattern.
  14. Evening all Fans of heat were starting to get excited last evening as the very real possibility of a classic "plume" of hot air advected from Iberia heaved into view. Let's see where we are tonight with the T+216 850s from the main models: Respectively, GFS OP, GFS Control, GEM, JMA and ECM: GEM looks the outlier with all the others showing hot air building from the south by Monday 23rd. JMA shows the plume already easing away to the east so may be progressive but GFS OP and Control and ECM all look very close. Five days on and for both GFS OP and Control, the heat has moved away. The problem for heat fans is the HP builds right over the top of the British Isles into FI cutting off the flow of hot air. It will be fine and settled and warm or very warm but really hot - perhaps briefly in the south but a the HP eases west or north west, a NE moves in and chases the heat away. I'm not currently seeing a prolonged hot spell - I do think 2-3 days of heat (daytime maxima above 30c) are very likely for the south just before the Bank Holiday before the cooler air returns. One thing I do see is a prolonged spell of settled conditions with little rain and hopefully some fine and sunny days.
  15. Late afternoon all After a bright and breezy start and middle to the day here in lowland East London, it's gone downhill rapidly in the past two hours as the shower/squall line has edged SE and now lies right through central London almost on the line of the Thames. A succession if heavy showers merging into a more continuous spell of moderate rain currently. The NW radar "suggests" the shower line is edging further SE so the worst may be over for us in the next hour or so.
  16. New Zealand getting a real taste of winter: https://www.stuff.co.nz/national/weather-news/126005400/heavy-snow-expected-as-new-zealand-hit-by-winter-freeze An unusually strong cold blast with LP developing just off the East Cape drawing up those cold Southerlies (note the 850s). Snow likely for higher elevations on the North Island as well overnight and into tomorrow (UK). Another cold push from the SW next weekend:
  17. Evening all With everyone of my acquaintance convinced we're having a heatwave in the second part of the month, I thought it was time I luxuriated in these wonderful heat-ridden charts with endless days of HP and 20c 850s and daytime maxima in the 30s. Apparently. Let's see where the T+240 850s take us tonight - GFS OP. GFS Control, GEM, JMA and ECM respectively GFS OP the most bullish for heat and that's far from discouraging at present with a brief push of +16 850s across the south and south east but other models keep the heat well to the south and south east suggesting (for now) the Atlantic LP will be too close to advect any hot air from Iberia. Back to the 500s and the T+360 charts from GFS OP and Control and the 06Z monthly CFS run: There's a couple of things to note for this observer - first is the continued signal for heights to sit to the north or north east - we've been here for much of the summer and the pattern which has helped the north and west of Britain seems set to continue. I also note the hint of tropical energy on GFS OP - this isn't the first run to feature a "fish" storm which recurves far to the east of land and thus carries a lot of energy back into the lower mid Atlantic. I think this is what we will need to kick the pattern a little and bring HP forward into the British Isles and NW Europe. It's not an unusual late summer/early autumn pattern.
  18. A few hints of something more settled next week but far from universal agreement. I've heard so many people tell me "there's going to be a big heatwave in the second half of the month" it must either be true or everyone's been reading the Express or Mail. One hint I think we can be looking for is a resumption of tropical activity in the lower Atlantic and off the North American coast - if we get a hurricane which stays further out to sea before re-curving that can, so to speak, give the Azores HP a "push" towards the British Isles and NW Europe. In any case, injecting some energy into what is currently quite a still North Atlantic can often trigger a push of heights to our advantage - not always - and sometimes ex-hurricanes aren't our friend but more often the not, we benefit from the energy redistribution in terms of building heights over us or close by - one of the reasons, I'd venture, why we often get fine spells in mid to late September for example. With the NOAA continuing to forecast an above-average season, it may be we'll be looking for charts such as this:
  19. What happens is a plume of air from the Azores HP is carried north and gets cut off as LP develops behind it. I've never seen anything like that on a chart - just thought it was worth a mention.
  20. Evening all Just a quick glance at tonight's 12Z output. GFS OP is very good especially in far FI with a strong build of heights from the south west and a push of tropical air to the north east keeping cyclogenesis well to the north west. Control nowhere near as good in truth. ECM ends on a decent vote suggesting we have only another week or so of unsettled conditions before the south of Britain, at any rate, starts to see conditions settle. JMA shows what the problem with the evolution might be - if the Azores HP doesn't ridge in strongly enough, LP establishes over Scandinavia and we get a cool NW'ly. Nothing really resolved as yet as you would expect.
  21. Evening all Another showery day and I suspect (looking at the NW radar) it's not quite done with east London. One shower developed more or less over East Ham and has intensified as it has moved east but the next storm is moving down the river towards us and there's plenty of rain for south and central London from that. The wind is now coming from the WNW so looking upstream a few showers over the south midlands but that may be our lot for today.
  22. Evening all It would be wrong to say there are no signs of any settled conditions on the 12Z output this evening. It would be fair to say it's all still in FI but there are hints and trends of the trough finally aligning positively and allowing the Azores HP to ridge NE across southern Britain. The 850s are reasonable without being spectacular in far FI so if you want dry and warm (rather than dry and hot) there are clear signs of something more to your liking. However, the more immediate is less promising and we could still have 10-14 days of this unsettled spell to get through.
  23. Evening all After yesterday's extraordinary deluge here in East London, a much calmer and quieter day (mercifully). A fresher feel this evening (also not unwelcome) as we transition into a cooler, more unsettled spell. Tonight I'll look at some T+216 500 HPA charts to see if there is a sign of a change: Charts for Wednesday August 4th - ECM, GEM, JMA, GFS OP and GFS Control GEM trying perhaps to pick up some of the theme from last night's ECM and tries to build a ridge across Southern Britain which prevents the Atlantic LP dropping down from the NW. To be blunt, GEM is an outlier at this time - it's the one that tries to send the jet back north while the others all hold the jet near to southern Britain. Looking further on (just a bit of fun, as Peter Snow would say) - GFS OP and Control at T+360: A bit more like the kind of August @Mike Poolehas been forecasting. To be fair, GFS often picks up trends and runs with them Control would be a very "typical" settled August pattern - OP is getting there slowly and note the rising heights to the south over Europe.
  24. Afternoon all Very heavy storm passed through East Ham 10-15 minutes ago. Heard thunder and saw one lightning flash. Intense rain - what was most unusual was this came from the NE, not from the south or west as you would expect. It's the first time I can recall a thunderstorm travelling NE-SW - we can get rain from that but not a storm. Very unusual and, as I say, very intense rainfall for a short period.
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