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Posted August 29 (edited) What of the change of month and the previous suggestions of improved warmer weather once again ? Still on cue whatever numerical operational model vicissitudes appear to indicate - albeit as per the theme of the beginning of this post, never a straightforward process at this junction of the Northern Hemisphere. As was the case in late July and early this month, the high frequency MJO signal has growing confidence to embark on another eastward progression across the topics, much as discussed in detail in previous posts. The cue to promote attempts at further downstream ridging. Deterministic RMM modelling between the ECM and GFS is coming together with this trend, but this less reliable MJO modelling in terms of suggested amplitude path is very open to further forecast adjustment (i.e on the upside) At present NWP is very keen to retain an element of a more dominant Atlantic ridge and the tendency to allow fronts to slip south as pressure falls ahead of it sometime around next weekend. Some caution is required in the coming days as to whether or not any further retrogressive Atlantic ridge signal is overdone or not beyond this time - not so much as to how it evolves at face value - but more in terms of how the longer term pans out. The lessons from late July and the obfuscated lead up to when the intense heatwave suddenly started to appear in numerical modelling were that these same numerical models were, as anticipated back then, too blindsided by the low frequency upstream signal and made late adjustments to over progressive inroads on cold fronts and return of cool North Atlantic air, due to over amplifying the incoming Atlantic ridge to the west of the UK, and therefore digging the polar front too far south. The reality was that downstream ridging across Europe and Scandinavia proved more resistant than advertised and the subsequent heat dome persisted for much longer than initially suggested This time around, there is clearly not going to be anything close to any extent of advected heat source later this week. However, irrespective of this, based on the suggestion of an amplitude MJO wave progressing right into the Pacific through September, this ultimately supports the sort of de-amplification upstream (and subsequent downstream amplification in this neck of the woods) that happened in early August. On this basis there is support for the idea of any renewed ridging coming in from the west, adjusting itself eastwards to become positioned to the east and drawing a plume of very warm air from southern europe and up through France and to knock on the door of the UK. It is more a question of timing of this, rather than if it happens at all. I am, as ever, suspicious and questioning of NWP trends and do not take each and every output at face value. The ideas behind any further plume potential lie beyond next weekends proceedings and based on the movements of the renewed ridge advancing eastwards into the following week. This rather than trying to retract the high westwards and lower pressure again across the UK and other parts of NW Europe. It seems counter intuitive to expect further retrogressive flow after next weekend when the tropical signal supports increased momentum upstream in the longer term. So, and for what it is worth as I do not profess at all to be a "forecaster" as such and rather simply look at diagnostic probabilities -, it may take some time to benefit areas further north and west, but the evolution of ridging may ultimately manifest itself as stretched between the European mainland, the UK and with some slight and very subtle discontinuous retrogression to the Azores/Atlantic high pressure zone. But not too much discontinuous retrogression to allow pressure to fall too much ahead of it across NW Europe. Bias susceptibility to too much Pacific amplification possibly an element with this within some numerical products and it is on this basis to not be overly distracted by operational output but monitor the trends on numerical models c/o the ensemble means and clusters. This over a day or two at a time, rather than draw instant conclusions from each and every suite. A very conducive outcome remains possible for some calm, warm and sunny September weather and evenings still warm enough for sitting outside with the lanterns and tea lights glowing in the now darker evenings than were enjoyed during the previous summer type spell of weather Edited August 29 by Tamara ---------------------------------------------------------------------------------------------------------- The above lengthy extract from a detailed analysis post towards the end of August requires little apology for re-posting because the evolution of the pattern has duly exposed the suspicions surrounding NWP that were expressed on this, and other occasions, around that period of time. The many various bolded parts are especially prescient. So, beautiful summer-like weather is here to cherish for early autumn Those tea-lights flickering gentle shadows in the darker evenings, as suggested to come in the bolded post, being the one key difference as a reminder to the change of season since that early to mid August spell of classic summer weather The 90 day Global Wind Oscillation plot, a phase plot depiction of global wind-flow inertia, tells the full story of the summer pattern and the quite clear departure from the default pattern during August as the GWO reflected a higher angular momentum regime away the tight orbiting of from the low momentum La Nina phases 1 and 2 during much of June and July - returning once more to a low angular momentum regime in late August.. Namely, a switch during early August to anticyclonic wave-breaking downstream across NW Europe as the Pacific pattern switched to a less amplified signature and re-configured the downstream pattern - as the rossby wavelength switched downstream accordingly Now, heading into the middle of September, we see a further downstream anticyclonic phase occurring at the time that, once again, rising relative angular momentum rallies the GWO orbits out of the lowest momentum phases and traces an orbit path along the lines of what was in progress at the beginning of August - on the cusp of higher momentum GWO phase 4. Though, important to note, this is based on a two day consolidated lag to Sunday 13th. and doesn't include latest developments subject to forthcoming update. What of the outlook? As everyone knows, further glorious weather to come through to the weekend itself (though of course regional variations with the easterly winds). Beyond that is another period of suspicion as to how keen NWP is to re-introduce the return of the trough digging as far south as it suggests. Is numerical modelling, once again, far too fast in wanting to overdo the return of influence of the La Nina walker circulation? Further out still - If the high frequency tropical convection stays active, does not slip into the doldrums, and continues to shake up the rossby wavelengths, then it will remain possible deep into autumn to see a continued variable mixed meridional theme that sees more departures from the typical Nina-esque Atlantic ridge and downstream trough. Should the high frequency tropical signal weaken , then the walker cell will fully prevail and strengthen La Nina considerably and the pattern quite possibly becomes a little more predictable in terms of the pattern wavelength, I would think, for those who , unlike me, are forecasters . At least as far as it is possible to make suggestions as to how patterns may pan out in a world of long term and unpredictable climate shift. In this scenario, the Atlantic ridge is suggested to increasingly be in charge with less interruption - and lead to a fair amount of polar maritime influences as this season progresses, for north western parts of Europe at least. The wavelength then looking to adjust the position and amplification of this ridge thereafter - with a flatter regime flowing around the perimeter of the ridging and ensuing in tandem with the more organised polar vortex. Therefore much depends on the character of this La Nina - whether it follows a 2017/2018 more east based nature, or whether it is the more familiarly seen (basin wide) traditional type. For me, I will have long completed my posting on this thread by such a time anyway - until next Spring. All being well and fingers crossed, I am by this time 1250 miles further south to escape the British winter. From a completely different perspective to the vast majority in the UK, it will be be very interesting to see how a first winters weather pans out,1250 miles further south and with that, another highly fascinating learning curve to experience and enjoy

Someone calm me down!!!

Hope your all well folks... Last night's EC46 keeps with the settled theme for the next week.. Later next week perhaps a more NW/SE split devoloping. Towards the months end we still have High Pressure Influence for more Southern parts, but perhaps more unsettled further North at times.. Moving into October the general theme of ridging at times for many parts, so still a chance of plenty of fine and settled conditions at times. It's not until the final 3rd of next month that things eventually become much more unsettled from the the NW.. I'm sure many would take that outcome considering all the current uncertainties around the world.. That's how it looks right now.... Enjoy the fine weather if you can. All the best... Matt

FI looks interesting

As ever a balancing act between long term factors, and the inevitable short term triggers that we have no chance of seeing this far out. It is possible to argue that the +IOD trashed last winter almost single handedly and more dramatically than many thought going in to the season. If we remove it, think of the low solar context, the weak/moderate Nina, the propensity for more extreme vortex events at either end of the spectrum - then there is no reason to write the season off. I've said elsewhere the days of a wall to wall cold season from Dec to March are next to 0. The modern context I think rules that out. But the opportunity for cold shots remains, and possibly in the modern context the extremes increase. eg 2018. I'd be more optimistic personally if the QBO had stayed on track - but it is what it is. I have no doubt that a smoothed 3 month average will provide a +NAO signature when modelled. The models default to this in any case, and we know we get more +NAO than -NAO in nearly every winter these days. But most would be happy with a 1 week spell of cold across the 12 week season. 2 weeks would be memorable. We can hope for this with carefully considered optimism each season. 1 year in 5 we will cash in.

What a stunning chart!

Blimey! When I first saw that, I thought it was temperature! I think I need arrange a trip to Barnard Castle!

And if the CFS keeps showing them,then i will keep on posting them,.... another stonker but this time in Feb Talking of Feb,where is @feb1991blizzard !!!

If you like high pressure, bank the Ukmo 12h!...As for the GEFS 12z mean, well, it’s hard to believe it’s mid September looking at tomorrow’s charts..SENSATIONAL!!! for the s / se!!..and plenty of high pressure to come for the rest of this week & well into next week and warming up again!

Superb at the moment for observing the planets with Venus, Mars, Jupiter and Saturn all visible to the naked eye at the moment. Jupiter and Saturn make their closest approach to each other, visually, as seen from Earth in the week before Christmas since 1623 and Mars makes its closest orbital approach to Earth at the start of October. Venus is a pre dawn object. Venus and the Moon yesterday morning My dad took these footage Mars, quite a bit of atmospheric distortion Saturn

Spot on mate! I would take a Polar martime airmass everyday from November 1st to March 1st! Agree with regards to Summer months - it is useless! Definitely welcome it though from late Autumn/Winter! Positives for me are thunder & lightning, graupel, snow, thunder snow and massive Cumulonimbus! Couple of pictures I took last Autumn/Winter with the airmass in question. Guess it depends on ones weather preference/location. Back to the models - ECM going for some rainfall/cooler temperatures from around 23/24th September. In the meantime some glorious warm and sunny weather to be had in parts of the UK! 31C today in Manston, Kent - lovely stuff! Pretty decent Autumn weather up here for the next few days. ECM seasonal went for a below average (temperatures) September across the UK and Ireland - something to keep an eye on. (Link below) https://effis.jrc.ec.europa.eu/applications/seasonal-forecast/ All the best to you all - hopefully everyone enjoys some warmth/sunshine! Not long until the most wonderful time of the year...

Do not adjust your sets, this is indeed snaw on the Gfs 12z op bringing a few hours of winter to parts of Scotland!

Many thanks @Tamara, I hope all goes well for you in Portugal. You'll probs get as much snow this winter as will I!?

The sky here looks awesome if nothing else. view to my NW view to my SW

Well those charts above are pretty much the "polar opposite" of what we have right now... Can we achieve surely the only ever year with 90F recorded in 4 separate months? Tomorrow is the big chance. AROME going for 31C, ARPEGE 32C but in Kent rather than London, so may suffer for lack of reporting stations. If only Gravesend was still running!

Those uppers look a bit marginal..

ECM losing the plot at day 7-10 today, far too unsettled. How quick can the recovery come after? Tropics all ablaze with storms and hurricanes, so i'm going to stick with a reasonable-ish outlook beyond the middle of next week, with the chance of some unexpected twists and turns to come!

Yes, same here - a very misty start. The pockets of cold air drifting off the nearby field kept misting up the patio doors. Reached 27.2C yesterday and 28C or 29C expected today. I see Arpege has a cheeky 31C showing down in Kent: Just snapped these lovely altocumulus drifting across the Suffolk sky:

Went for a walk earlier this evening and you wouldn’t have thought it was September (apart from the fact it was getting dark at 7:30 and there weren’t any tourists about).

Give me a polar maritime airmass any day over a tropical maritime one, the latter whatever the time of year brings low cloud shrouding everything drizzle or rain and a general dankness, and always mild. Polar maritime airmasses bring sunshine shower type weather, often very clear sparkling air, bracing weather. Downside in summer is cool weather, in winter, can bring a mix of rain, hail, sleet and snow, if cold enough and with troughs in the flow more organised snow. Very seasonal. Back to the models, remainder of the week mostly dry and sunny away from eastern coastal districts where cloud may be more stubborn, and notably cooler as we pick up an easterly feed from a colder air source. Western parts may do best for sunshine and with lighter winds here it will feel very pleasant, high teen maxima for many though as opposed to high 20s. Next week, models keen to bring the longwave atlantic trough back in with heights squeezed away, an increasingly unsettled outlook with bouts of wind and rain and turning quite chilly in the north eventually with some colder uppers invading. Traditionally we see a general change to more autumnal weather once the equinox comes.

Very warm humid day with lots of itchy corn lice about my favourite insect . Spraying whins along side fences today as they seem to have germinated very well in the dry soil conditions over summer. Geese starting to head south. Autumn tree colours now are just fabulous probably down to basically very dry soils over the summer and I think are earlier than usual too.Being so warm with an autumnal looking countryside did not seem right today. Currently 14c

Blimey. That'll do for me. Bread and milk buy bread and milk..

Aye, so can I... It's called an 'Equinoctial Kick in The Goolies'!

High of 28.4C at Leeds Uni. Some wild parakeets in Roundhay Park today - they're becoming an increasingly common sight in Leeds. Guess they finally migrated from down south. I wonder how far north they’ll move?

My car which is the most accurate ive ever known- matches my home weather station- it showed 32c today in Gravesend! So annoying we have no official data here anymore. It felt really humid also, I also feel the town I moved from- Dartford is even hotter than Gravesend as the car thermometer often shows higher temps here as well as parts of SE London and Dartford town centre is in a valley, and set back further from the river.

Could just be a blip @sheikhy ! Looks like a slightly more unsettled spell by the middle of next week, but generally the main storm track looks like staying to the NW of the UK after: Could be your traditional NW/SE split towards the end of the month. With AAM staying relatively high, i don't see any plunge into full-on zonal trash here just for now:

I have a feeling that we are in for an anticyclonic dominated month. Whilst it does cool down a little at the end of the week, temperatures will still be above average and it's looking fairly dry in some places. Even though it's early days, I hope we do get a proper autumn this year. As opposed to going straight from summer and into winter.

Big difference between the North Americans models this evening at 240t. You could not make this up really. Possibly both going down the wrong path. Who knows, think hurricane season starting to play silly games with the longer term outputs on display ! C

I must admit I like this sort of weather in summer managed to reach 26.4c with humidity around 70% but in September (autumn), it’s not so nice and I’d rather see some cooler days and nights. Having said that I still at least realise this is what most of the general public want and enjoy and going for a walk to the park or the beach will prove this.

And i can see why Karl

Glorious day here in Bexhill. 25.5c

I've noticed since installing my weather station that, due to my garden being screened to the east and west by my house and a large wood, the wind direction recorder is only really of any use for telling me whether the wind is generally from the north or south. Today it's generally from the north. But hardly there at all. Meanwhile it's raining, 1.8mm since it started at 08:00, the temperature is 14.3 deg.C with a minimum of 14.1 deg.C overnight, there's total cloud cover and 94% relative humidity.

Couple of Cams on the Coast south of Mobile (to the West of Pensacola) Looking very rough! WARNING: They stupidly decided to put fake wave noises on the streams, so might as well just mute them

No. I'm actually very optimistic for this winter.

Here's the 5 day animation of the sea ice. I post updates with this animation and some some other images each day on twitter and the sea ice forum, but I can put them here too if there's enough interest.

Lovely evening here and an all around decent day. Tomorrow looks wet but then a good few dry days to come if a little cooler.

It's much warmer than I expected, or what the Met O forecast was forecasting as recently as yesterday. Feels like August all over again. Looking forward to the fresher, if still sunny weather later this week.

The one that springs to mind for me is Ophelia https://en.m.wikipedia.org/wiki/Hurricane_Ophelia_(2017)

15.2c to the 14th 1.1c above the 61 to 90 average 0.4c above the 81 to 10 average ___________________________ Current high this month 15.2c to the 9th & 14th Current low this month 13.8c to the 1st

Hurricanes are strange and surprising beasts. Despite moving so slow over very warm waters, Sally has weakened this morning and she currently has 85mph sustained winds so back down to category 1. I guess some dry air got in the mix.

i don't think so, based on current ECM mean for Birmingham, (usually a good guide for CET zone), looks like you are well in the frame with a few consecutive 12.5's at the end of the run.

Top UK temp was 29.6c at Charlwood in Surrey, British Isles 30.8C in Jersey.

Not to be trusted

Beautiful mid Septembers day I’d say one of nicest of year, max 27.2C but quite nice in sun, in the earlier part of summer I find it too intense.

Had a nice diurnal range today - a low of 9.9c last night and then managed 28.9c this afternoon! Unfortunately I don’t think it’ll drop that low again tonight as it’s still 18.6c now

This cam looks to be in the sweet spot for landfall atm

Just sticking this astonishing GOES snapshot from the NOAA in here. If there were anymore in the Atlantic we'd have to start to dob them in for breaking "the rule of six"!

Tomorrow’s storm risk looking tricky as always but main agreement at the minute looks like toward Inverness, perhaps @Northernlights seeing something but with that front really anywhere in Scotland will be at risk which the euro4 is the most active.

15.0c to the 13th 0.8c above the 61 to 90 average 0.2c above the 81 to 10 average ___________________________ Current high this month 15.2c to the 9th Current low this month 13.8c to the 1st