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ECM is certainly interesting at the moment - ensembles projecting more atlantic influence inbound than their seasonal forecast run on 1st Sept suggested might be the case, and I would agree that all that warm water to the SW might help spawn early pockets of autumnal activity. Quite sharp SST gradient out to our west too....and with pacific forcing currently unremarkable flattish activity pushing ever closer to western fringes looks possible. Too early to get particularly excited about the forthcoming winter season, but the number of weather extremes we seem to be experiencing globally now suggests plenty to keep us entertained. I worry for my children in terms of global climate trends...but from a selfish angle a melting ice cap and impact of bottled warmth in pockets around the world means we can expect the previously unexpected. The incredible destruction of the vortex last season with easterly winds nearly circling the globe will live long in the memory, even if they were so extreme they conspired to end that siberian blast earlier than was expected. In another 3 or 4 weeks we can begin the traditional dissection of long term drivers. Noone will get it absolutely right - but it is fun nonetheless.

Yes but if you see rampant zonality in Nov all the way around the globe at 50-60N, then unlikely to see the above patterns in Dec, im not one that subscribes to the view that you cant have a very wet troughy UK in Nov and still have a blocked Dec but you really need the Zonality to not get too far past the Prime meridian, you still want the Russian high to be a major player. its about building blocks.

Had to share this:

Summers over..it's time for a new thread!!!..or is it? the Ecm 12z doesn't agree.?️..Ahhhaaaaaaaaaaaa

A changeable but relatively quiet week, albeit still inclined to to a NW/SE split but with an invigorated vortex and the remnants of tropical storms in the mix the possibility of some wet and windy weather in the near future is becoming a favored option. But that's getting ahead of ourselves so the current NH profile and surface analysis at midnight. The rain associated with the fronts is currently over northern England and Wales and this will move slowly south during the day tending to fizzle out as it goes. But the movement of the waving front and precipitation intensity is not straight forward and pulses of rain tend to run along it as it slows, and even trots north again for a time, intensifying the rain once more. So the south/south east will remain dry whilst further north over west Scotland the squally showers will persist. So during the evening and overnight the intensifying band of rain will move north for a while before once again tracking south and clearing the south coast by midday Wednesday. Meanwhile the blustery showers will continue, mainly over western Scotland but also some activity over N. Ireland and north west England. By the end of the day all of the UK is in the cooler air. By Thursday we are in a N/S scenario with sunny interval and dry over much of England and Wales whilst further north, as low pressure skirts Scotland and the weakening cold front tracks south, blustery showers will again be the order of the day. A very similar day on Friday with the showers moving a tad further south Saturday will mostly be dry and fairly sunny with just a few showers still in the north west but by early evening rain will be approaching Ireland from the next frontal system. And the NH profile at T120 and the onset of the shenanigans from the vortex and the TS remnants

Steve, thanks for a great topic and detailed opening post. I posted the following comment on an Irish Facebook forum in July. "From what i can see, the same synoptics in general have prevailed since the historic snow storm back at the end of February. In winter this gives snow, in summer sunny and hot. I cannot remember any such prolonged synoptic similarities (easterlies) in all the 40 years i have been weather watching. Is this linked to the slowdown in the North Atlantic drift? This being caused by the speed up in the melting of the Artic ice and Greenland Ice? Could the NAD slowdown be speeding up? We know what this would eventually cause. Perhaps I am being over dramatic. We shall see." I am not there most techical member here and I just have observed the weather for the last 50 years and studied the charts for as long.... and things, i believe, have changed big time since early in the year. I did predict to family members and friends after the Late February and 18th March cold spell that if the weather synoptics continued as they were at that time we would be in for a scorcher of a Summer. The synoptics generally stayed the same and lo and behold the hottest, sunniest and longest Summer came to Ireland this year. Stephen, my technical reasons for the change above may be quite simplistic. I think perhaps, what you have stated in detail may be actually what is taking place. This winter could be facinitating and indeed one to watch, based on your thoughts.

Yes, these are the pressure / height patterns I would like to see in late Oct / Nov.

Well, it's nice to see the actual AAM finally trending positive and the GWO on a phase 3-4 movement, after the concerns of recent days with the observations refusing to follow the model simulations. Even now, how much AAM rise occurs is questionable - but even a little bit may well be enough to direct ex-Helene in a manner that's very conducive to large-scale warm air advection across the UK from the SSW or S. The tropical infusion results in an exceptionally warm night or two in recent ECM and GFS runs. The early Wed temps on the 06z GFS aren't far off the long-term average maximums for mid-September. Once ex-Helene has moved through, the main question is then to what extent the Atlantic trough, boosted by the tropical infusion, is able to overpower the Euro ridge. I expect GFS is displaying some classic bias with that, but ECM may be too, i.e. while the former is too progressive, the latter might not be progressive enough. The balance of power here will have a huge effect on UK temperatures.

Greetings- nice thread,hope you don't mind me butting in...David As well as the tropical systems I think it's worth pointing out the conveyor belt of moisture affecting the NW UK. The pattern is just mobile enough to avoid very high accumulations over the Lakes and SW Scotland and the max in IVT (Integrated [water] Vapor Transport) is moving into the North Sea this morning. Radar accumulations suggest only ~50mm in 24hr in parts of the NW rather than the 100mm+ totals associated with 'Atmospheric River' flooding events. IR image https://aviationweather.gov/satellite MIMIC Total Precipitable Water http://tropic.ssec.wisc.edu/real-time/mtpw2m/product.php?color_type=tpw_nrl_colors&layer=tpw&prod=natl&timespan=24hrs&anim=html5 IVT product courtesy Ben Moore, http://www.atmos.albany.edu/student/bmoore/natlantic_ivt.html

Plume-tastic ECM this morning, turning very warm through next week as the trough stalls out west. One of a number of options with the tropical low.

Crazy, on the GFS Helene still has a residual warm core as she approaches Cornwall -

I have to say to all the people that moan about rain in the UK - this is what you call rain!!! - to put it in perspective, if the more extreme model runs verify, this hurricane will give 6 months - 1 years worth of the rainfall I would expect to see in 24-48 hours, if I had that where I live, undoubtably the water would be above peoples roofs and thousands would drown.

Completely agree. Even in the extremely wet and unsettled Nov 2009 you could see the building blocks appearing on a hemispheric scale.

https://www.visitob.com/webcams/avalon-fishing-pier-webcam/ http://www.midatlanticengineeringservice.com/harborcam.html https://www.a1mountainrealty.com/webcam/ https://sapphirevalleyresort.com/web_cam_fairfield_lake.html http://68.71.163.28:1879/view/viewer_index.shtml?id=2663 https://www.visitob.com/webcams/kill-devil-hills-nc-beach-webcam/ https://www.visitob.com/webcams/downtown-manteo-webcam/ https://www.visitob.com/webcams/manteo-marina-webcam/ https://www.visitob.com/webcams/corolla-light-resort-beach-webcam/ A few cams to monitor. The you tube frying pan structure should be good as it has sound and is gonna get hit hard.

Afternoon- Just checked in on Florence, after the ERC the eye is now perfectly clear & shows no signs of being ragged - in that its very circular, nice deep convection rebuilding around the core & cold cloud tops- If theres going to be a run @Cat 5 its just started....

completely agree, thats the timing the anglo saxons used and its their words we use for the seasons.... and it explains why 'midsummers day' is june 24th... its clearly not summer like today, nor is it going to be, and for most of us its not been summer like for a while apart from a few odd days here and there (obvs the favoured southeast might disagree). my 'memories' on facebook reveal that my daily weather blogs over the last several years too also talk of autumnal weather. 'nice' septembers with sunshine and heat are rarer then one would imagine. ps... isnt beltane april 30th?..

Lovely Saturday, crap Sunday and an even worse Monday! We had over an inch of rain from Saturday through till yesterday morning. Heavy bursts of rain yesterday interspersed with clouds of midges. Pure mince! I see we could be in for a wee blast next Wednesday, first of the equinoctial gales! Perfect! I have a visitor coming up here by bus, be interesting to see if they get over the bridge!

I’ve been holding off posting for the last two hrs trying to make sense if the models and Florence. This is just my opinion so take it with a pinch of salt. Gfs is another silly run, it has it touching the outer banks, going back out to see and then coming back sw and making landfall again at the Carolinas border. Ec is bang on the last few runs. Hitting just south of willmington. Since it initiated well I would strongly favour this solution. Imho there isn’t a model that exists that will predict intensification from now to landfall. It will all be down tk internals and Florence herself. There was certainly an attempt at an ewrc. This was forced on the hurricane by a lack of outflow. Which allowed the eyewall to become week and dry air to enter the system. This conversely set off better outflow and provided a turbo boost to the convection band. The attempt at an erc was swept away and the eye wall become greatly strengthened. The remains of the attempted erc have been pushed out. But enough of an erc has taken place to provide a likely expanded eye Sometimes, this can be sufficient to allow a period of intensification as the core has more vigour to contract. Sometimes, it just leads to a period of stagnation. Regardless, Florence is starting to become a big hurricane in size. All of these internal changes are probably just expanding the sustained 70-100mph winds by quite a margin. The next few hours will see her looking scary again imho.

Lovely GFS, Snow advancing westwards in Russia + vertical WAA into pole.

If that eye shrinks, the storm intensifies. If that eye shrinks too much, an outer eyewall can develop. If an outer eyewall develops, she undergoes an EWRC and de-intensifies... but does so at the cost of becoming a larger storm. After EWRC, it's then a question of whether she has the time and environmental conditions to reintensify. The bigger she is and the more intense she is, the worse it gets for the Carolinas.... not to mention Pittsburgh down the line (all that moisture has to be dumped somewhere once the storm's not intense enough to support it aloft, after all). Basically, there's no scenario in which this ends well as things stand.

Evening....Big disagreement from both gfs and ecm in the near term , but both computer models showing a stormy period in the next ten days , " Folks Due to the infusion of extropical storms across the Atlantic" computer models are in disarray ....Watch This Space

Can't remember too many times of recent years that these type storms which have developed from southerly latitudes have impacted that greatly on these isles in regards to high wind and heavy rainfall (well certainly towards the south)...always seems to suck up very warm air as being the most noteworthy point...all I can say is yuck!

John For different reasons, but on your lines I think if the set up continues we’ll see a switch to a very cold early winter. This whole year is fascinating and this minima is looking a fair bit deeper than the last...and thus mouthwatering times for me over coming few years BFTP

Actually, and probably just for fun given uncertainty, ECM does go on to deliver a real final blast of summer at T240: I think this is a decent bet for reasons expressed in my last post, but considerable uncertainty remains.

cool EC! still going for mon-wed kinda plume, similar to summer before last, plumes tended to arrive Tue/wed, fresher from the west Thurs, won't get me any 'likes' like 2 posts above, but who gives a damn, 5 likes for no charts, talking about winter

Pretty standard for all emergency evacuation plans in the US. I've seen in put in practice for wild fires too. I'd love to know whether the UK has any plans like that. Obviously it's less likely to be of use given the dearth of major events, but I'd like to think it's not "put the kettle on, man up and do your bit for Blighty".

Sunny Sheffield unchanged at 14.6C rainfall now 8.8mm 13.5% of the monthly average.

Angers me when people are so pig-headed and refuse to evacuate. If they want to risk their lives, then fine, but there will inevitably be people risking their lives to try and rescue them when things go wrong.

15.1 to the 10th 0.6 above the 61 to 90 average 0.1 below the 81 to 10 average __________________________________ Current high this month 17.4 to the 2nd & 3rd Current low this month 14.9 to the 8th

Somewhat bizarrely (and surely coincidentally) the 6z has almost identical synoptics at nearly the same timeframe:

Issac is heading west towards the southern Caribbean, it's Hurricane Helene which is forecast to swing NW then N towards the Azores this weekend then, if EC is to be believed, moving N/NE west of Ireland early next week, while 00z GFS took the much weakened ex-TS NE into SW UK while the 6z GFS takes it towards Iberia … big uncertainty!

So silly season is upon us, with the behavior of hurricanes throwing up all sorts. Some runs this morning like the GFS continue to push ex Helene in our direction, initiating a wet and windy period. However, ECM gets Helene through the pattern faster and it ends up north of Scotland, dragging up a warm southerly in its wake, and temperatures close to 30C in the SE eventually. Looking at all the runs, there currently seems a fair split between both options, with most runs now giving up on the idea of stalling Helene for days by the Azores.

I think the astronomical definition is daft. It surely should be the period where the sun is at highest and strongest, the greatest period of daylight of the year and that is between Beltane (7th May) and Lughnasadh (7th August). That to me, makes logically sense. After all we are talking astronomically not meteorologically here

Someone needs to have a word with the local forecasters...

Wow

The National Hurricane Centre must be flat out with this lot. 6 areas of interest and something that's not exited Africa yet aswell. https://www.nhc.noaa.gov/gtwo.php?basin=atlc&fdays=2

deep FI, about same distance away, great EC

The ecm has TS Helene drifting north and starting to engage with the Atlantic trough. The key to future movement may well be down the strength and direction of ridging to the east and thus wind and rain impacts on the UK and possible WAA

Pub run has a brief plume and temps pushing 30C in the southeast from T180 onwards. All these tropical shenanigans create a lot of confusion.

Completely agree. With so many hurricanes on the go, a fuelled up jet and the things you mention, I feel the second half of September could see a very notable storm for the UK - or two.

Given the SST anomalies to our S&W would you count on any storm losing much intensity before it reaches our shores? I think this general set up was warned about a few weeks back by some on here, given the cooling to our N and extremely warm SSTs around the UK after such a warm summer. If nothing else, there could be copious amounts of rain falling across the UK this autumn- there is certainly the potential.

I didn’t want to put the cat 5 one up until/unless it reaches cat 5 as it always scares the hell out of me !

Not an unattractive end to the GFS between +240 and +384: Of course, this is a long way off in weather forecasting terms and it won't happen like this, will it, but it's got to be worth at least one sunglasses emoji from Frosty, surely?

This a beautiful satellite picture from NOAA showing the three tropical disturbances...

Gusts to 103 mph in the southwest approaches beforehand, then over 80 mph in the Bristol channel and north Wales. 60-70 mph widespread inland, then 70-80 in the lee of the pennines, according to weather.us

Cat 5s are a breed to their own. They are rare because the internal dynamics need to be very exact. The eye often become unstable at 120kts and above and inflow and outflow channels needs to be very well balanced. Ercs need to be undertaken normally and the eye wall needs to be stronger enough to sustain the cat 5 winds but weak enough to allow the erc to complete. All of this on sufficient ocean heat content, low shear and normally an upper high. A cat 4 is relatively simple compared to all this. A cat 5 might be possible, but still needs a few things to come into play.