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Olá a todos 21 to 23C has been the benchmark each day here in Portugal since the second part of last week, and has allowed a lot of outdoor work to be completed without seeking sanctuary in the middle of the day from an inferno in the sky This,, following some heat and spectacular evening thunderstorm activity in the first part of last week. These much cooler levels are very conducive for getting things done throughout the day, but are distinctly below average for Portugal while at the same time they would constitute acceptable levels of warmth for many in the UK - very evidently compared to the parallel cool-off that has happened in the UK over the same period and induced some truly unseasonal coolness along with the rain The heat is set to ratchet up here again during this week and indeed, following several practice tests over recent weeks, is probably the makings of summer proper to come most likely well into the autumn (as defined by seasonal months). As far as the UK is concerned, its less straightforward as it often is the case, though that said, the risks of overplaying a changeable/unsettled pattern are at least as large as the converse in my opinion. Why is this the case? Long explanations but quite clear conclusions in essence. It is correct to state, as for example @Singularityhas done from a read back of recent days posts, that another lull phase of the 'mini ENSO cycle' (aka high frequency tropical phasing) is in progress - but it is also true what he says that it is not as simple as an x+y= fixed formula either when, it comes to -ve AAM = unsettled and cool and +ve AAM =settled and or even thundery and hot warm (in context of summer at least) The Global Synoptic Dynamical Mode (GSDM), in its most simplistic terms, gives an overview of global wind-flow budgets and an insight, through graph and plot depictions of cross sections of wind-flow, latitudinally and also of longitude - where -ve wind-flows (easterly) and +ve wind-flows (westerly) are occurring at a given time, and on a rolling forward basis. The aggregate total of these wind-flows tells you whether there is surplus -ve or +ve inertia within the global atmospheric circulation - and as part of a break-down on this wind-flow budget, measures the turning force of torque mechanisms (where changes in flow occur and generate of flow) switches, and express them in terms of angular momentum tendency (-ve or +ve) according to the overall wind-flow budget within the global circulation. On this basis the pattern is more likely to retrogress during phases of dominant deceleration of wind-flow as easterly wind inertia is added from the tropics and beefs up sub tropical ridging in the Pacific and then the Atlantic -while at the same time these retrogressions create a downstream trough response. The converse holds true when westerly winds are added from the tropics into the atmospheric circulation and forward momentum adjusts the rossby pattern wavelength poleward and eastwards. This all sounds a bit like the x+y formula though doesn't it? What is of far more importance is the ongoing tendency of momentum within the atmospheric circulation (not the total -ve or +ve aggregate of momentum. Also, at what latitude and wavelength, and indeed in what hemisphere (which can have stratospheric effects and define the respective annular modes at the poles) momentum is being added or taken away. To put some context of there here and now, some GSDM plots will follow in due course to explain the current wind-flow budgets and how they are impacting the numerical modelling. Also some suggestions as to how the diagnostic might evolve NWP in the foreseeable future. As a prelude to this: the previous post earlier this month suggested that strength and amplitude of the MJO 'mini ENSO cycle would determine tendency of momentum and whether the anticyclonic pattern of the earlier part of the month would tend to hold a similar wavelength or, show an inclination to retrogress. There was also a suggestion that NWP might overdo suggestions of retrogression in the longer range based on the state of the summer polar field (much more stable as predicted since the strong feedbacks of the late winter and much of the Spring) and also based on the fact that trade winds have eased more generally as La Nina has taken more of a backseat and this has been something of a floor on angular momentum tendency (the amount of easterly inertia propagated from across the tropics) To illustrate both these proxies: The southern oscillation index (SOI) as a pressure differential sign-poster within the Equatorial Pacific sign posts a sustained neutral trend and points to a cap on the amount of easterly inertia potential generated within the tropics Another way of representing this modest impact is within the Hovmollers plots which show only sporadic trade wind phases (easterly inertia shaded blue) across the tropics with pockets of forward momentum (westerly wind convergence zones shaded red) c/o cyclonic impacts across the African continent, Indian Ocean, and the far eastern Equatorial Pacific. All said, frictional torque tendency has no doubt still turned negative as tropical convective activity has waned rather quicker than anticipated earlier in the month (Lets express this as a measure of the amount of easterly wind inertia that creates a negative torque response and creates sub tropical high pressure amplification at the inflection point of where easterlies replace westerly/forward momentum. Note however from the plot that a large proportion of -ve tendency is evident within the southern hemisphere and that this means that impacts within the northern hemisphere are muted by proportion. Notwithstanding that, the effect of modest upstream -ve torque tendency within the tropics, is to inflate and retrogress equatorial ridging into the sub tropics, occurring, as said. at the source of inflection point of -ve torque in the Equatorial Pacific where convective suppression is evident. Frictional torque tendency usually leads mountain torque tendency as these inertia switches propagate between the tropics and extra tropics. The lagged impact of added (but limited) deceleration inertia from tropics> extra tropics in accordance with the laws of conservation of angular momentum is to add (weak) forward momentum strength to the downstream jet from the Pacific (within the extra tropics) across North America into the North Atlantic, So the spectre of a beefed up sub tropical ridge downstream in the Atlantic, and with a relatively diffuse jet stream riding across the northern flank of the ridging sounds about right with what is being advertised by NWP. Modelling has been consistent with this, but also is struggling with the proportions of this inertia which, as suggested, is not manifest of any full blown summertime La Nina wavelength response. As is/has been well commented on by others, this is producing erratic intra day solutions based on very flabby cut-off low pressure areas breaking off from the diffuse Atlantic jet coming off the US and dropping south around the perimeter of the sub tropical ridging. The recent -ve inertia switches are represented in wind-flow phase plot depiction form by the Global Wind Oscillation - which is a barometer of how much impact (-ve or +v) the atmospheric circulation is acting co-operatively or 'destructively (a-typical) to the base state. Based on calculated tendency of AAM (which budgets together aggregate global torque contributions to wind-flow) we see, once again, only weak to moderate -ve tendency on the jet stream - producing proportionately weak Nina-esque impact on the pattern As such, the GWO has laddered very slowly down into a quite incoherent and weak Phase 0 signal - which is hard to define in synoptic terms, but erratic and fitful discontinuous retrogression amidst the pockets of equally tatty pockets of cut-off low features is the sum of the parts. Trying to assess independent parts of the atmospheric budgets through composite matches is fraught with error based on the present scattergun wind-flow inertia budgets that have to be seen as a complete GSDM diagnostic rather than back of a fag packet assumptions about neutral ENSO states and assumptions about MJO modelling. The latter has to be viewed based on periodicity timelines which operate up to 60 to 90 day timescales (with empirical feedback loops within them). On this basis, and in the absence of taking into account any of the various interlinked factors, it is not possible to predict the GWO with any accuracy without looking to see how much potential bandwidth there is within the atmospheric circulation to release latent Nina-esque forcing (low angular momentum regime) Or indeed any other forcing at any other given time based on torque mechanism strength that can be created within weak GWO forcing as part of a strongly neutral atmospheric response and behaviour network The resultant dogs breakfast pattern, as expressed in synoptic NWP terms, looks sustainable till the tropics give the pattern a kick as the next high frequency wave likely gears up heading through July. However, sub tropical Azores ridging based on feedbacks loops assured within a weakly negative/neutral atmospheric and ocean base state, offers lead on the pattern in the period heading into the first part of July. Its hard to see the GWO having a floor limit much below a very weak Phase 0/1/2/3 treading water orbit - and based on the benign state of the polar field, this gives little appetite for poleward amplifying Atlantic/Greenland ridges trapping suppressed low pressure systems across mid latitude such as happened in strongly tanking -AO La Nina summers of 2007 and 2011 etc. Therefore, all in all, that brings the summary back to the opening gambit. Better to not overstate the -ve inertia potential of this pattern during this 'lull momentum' phase which has evidential limitation as shown through proxies and GSDM diagnostics. I would be watching for resumed eastward progression of quite strong Azores ridging (possibly towards Scandinavia) during July with a continuing stable polar profile to support keeping the jet stream to the north for those in NW Europe (UK) closest to such traffic. This should put something of a lid on any inroads of frontal systems brushing across those further NW in UK and NW Europe. Those of us further south in Mediterranean southern Europe maybe should keep an eye on true heatwave potential and make the most of getting outdoor work done in the garden and on the land before siesta time and air con take over proceedings

Well i dont see anything bad on these charts... ok, that shortwave feature over the weekend *might* upset things a bit, but concentrating on one wetter run whist other runs are drier and sunnier is a bit daft imho. these charts suggest the Azores high ridging Eastward across the UK, thus supporting most of the operation runs that currently show this. To my eye, these charts suggest a lot of fine summers weather, no heatwave (yet) but certainly drier than normal, only a light westerly mean upper flow, plenty of sunny/bright/fine summers weather....

The ECM 0z ensemble mean looks increasingly settled in the mid / longer term as the Azores high / ridge influence becomes stronger?.. !!!!... (broad brushstrokes) BUT it really could be a decent end to June / start to July..to me it’s a very acceptable mean for the height of summer?! ?

The BBC still aren't going for much rain at all this weekend and nor are the Met Office at this stage. If the weekend was going to be as catastrophic as many are predicting on here I'm sure they would have picked it up by now. I would be shocked if they are trumped by an army of amateur model watchers in here- but stranger things have happened I guess!

NLCs visible from Howth tonight.

No science to support this, but I often find new month new weather. Maybe it is just perception, but ECM T216 starts July on a very positive note:

I’m still hopeful for a decent start to July despite what some are saying!..the GEFS 0z mean looks ridgy which is reflected by some of these anticyclonic perturbations...fingers crossed..!!

My View at 12.30 am this morning.

Caught the display on my timelapse

sorry i completely disagree with you.. the UKMO was not an outlier.. it was pretty much bang on IF you take any heed of the NOAA anomaly charts... and its not vanished today.. The outlook is pretty certain as far as im concerned, high pressure will build to our near west and a positive pressure anomaly will persist over the uk not only in the 6-10 day timeframe but the 8-14 day too. The outlook is pretty certain, its going to be fairly fine, below average rains, calm, not completely settled and no heatwave, but a lot of really decent summers weather. Im not going to argue about the detail, but .... DEAL!

GFS 12Z at T+291 isn't bad:

The UK hasn't lacked record high temperatures in recent years to be fair. Three months set records in 2019: February (21.2C), July (38.7C) and December (18.7C). Also in February 2021 Braemar recorded the lowest February minimum since 1955 (-23.0C). August 2020 had a very notable heatwave. My main criticism of this climate is the high frequency of setups with lots of cloud, the odd bit of sun and the odd bit of rain, and not much going on, but the lack of temperatures well into the 40s Celsius is not something I'd criticise our climate for.

The UK has the most mobile weather of nearly any on the planet, boring it is not, trust me baking in those temps is a nightmare, i've been there and worked in temps nudging that, horrific. Give me the UK climate any day!

ECM 0z ensemble mean Looking very promising. Decent mean for the end of June / start of July

Hoping for some summer weather from this weekend… my partner and I are witnesses at a friends (twice cancelled) small wedding in Matlock on Saturday… then down to my Mums in Somerset Sunday to see my mum, aunties, sister and nephew for first time since august for my 94 year old Nans funeral…bless her… then up to leamington spa for another nephews wedding on 3rd July…

Tonight’s ECM 12z ensemble mean clearly improves longer term, increasing Azores high / ridge influence and becoming warmer...just as the operational...so...for sure there’s encouraging signs of a decent end to June and start to July?..especially further south!...sincerely I’m hoping for a good summer!

I agree. I do not understand why people would want to experience such extreme heat. I bet a lot of the people in the US would love to swap places with our climate. I personally love love our temperate maritime climate - cool(ish) summers, mild(ish) winters and not too much baking hot sunshine.

I don't trust this ECM but I hope it's right. Warm and sunny by Monday if it's true

I think the best thing to do is build a massive roof over UK. Put an artificial sun up the corner. A few heaters spaced around . Ambient temp about 23c. With the scope to pretend the odd heatwave by turning the heaters up to 29c. A sort of scaled down centre court at Wimbledon.

Sorry if I appear blunt ELR, but get a Covid test done and (fingers crossed) you will then be able to put your mind at rest.

Well last night was absolutely horrible for me. Felt very poorly all day yesterday and last night I became extremely cold and shivery. Went to bed in dressing gown and put two duvets on the bed and I was still freezing. Had to get the hot water bottle out (which I haven’t used for years) but got really hot so had to take it off. Eventually got to sleep around 2 am. The room temperature was 20°C so not cold, though cooler than recent nights (unfortunately that the night I was cold and shivery had to be ridiculously cold for the time of year, there was condensation starting to form on the windows!) Feeling slightly better today, but still poorly with a runny/stuffy nose, thick head and feeling very groggy. Hopefully it’s just a bad cold and not this Indian variant doing the rounds. Weather looks very benign next few days, mix of sun, cloud, the odd shower and temperatures in the high teens. BBC Weather forecast for Nelson, Lancashire. Today: Sunny Intervals. Max 17°C, min 7°C. Wind 9mph N. https://www.bbc.co.uk/weather/2641810

I’d be surprised if we saw widespread totals like that, locally perhaps but I suspect a lot of areas could stay dry if we are dealing with showers. This looks better than the last few days at least, in fact many could have some pretty decent weather and if we are dealing with showers/thunderstorms then there is a bit of interest in the mix. One concern is the potential for winds off the north sea on the ECM suite that could bring a lot of mist/low cloud. So edging the final position of that shallow low westwards would be helpful as that should allow more of an east/south easterly element to the winds.

What a lovely morning, and warming up nicely after a chilly night.

And here is the GFS 00Z; wishy-washy just about sums it up, IMO: But at least we lose the current nagging NE wind.

Plenty of tweets of UK sightings tonight. Sadly clouded out here. #noctilucentclouds

Barely a cloud in the sky and very pleasant in the sun, so with England due to play in the euros there's no excuse needed for beer and bbq.

Shap went down to 0 degrees this morning, some Decembers don't see many such mins..

Oooo .... a nice clear night coming up and a 3 day old Aim that, to me, is screaming a low bright display Good luck all

ECM for next week and rain anomaly And the Temp anomaly Since end of May I've been living a charmed existence over here, still 0.8mm for the month, lots of sun and tan and mean temp running 0.6c above monthly average. Certainly not complaining if we get a little rain over the next couple of days.

3.7C was the low here this morning. Not the coldest June minimum I've ever recorded though but still chilly for the time of year.

Here’s a small sample of what early July might bring from the GEFS 6z as for the mean, it’s not bad, the Azores high / ridge waxes and wanes but there is no strong signal for any significant Atlantic influence away from the far nw / n?....as I’ve been saying, it could be a decent end to June / early July for the majority?....

Another glorious summer day on the South Coast (not) - just 12 degrees again! My husband has just been speaking to a colleague in South Africa who was complaining that it was 'freezing' and he was wearing his overcoat - this is in a temperature of 20 degrees! Even that would be better than this lot!

Well well what's this?! Clear and Blue! (for the moment) it won't last forever but a nice welcome change

The regime forecast from the ECM was interesting yesterday: Blocked weather dominating all through July. 500mb update also shows +ve heights over the UK, and low polar and Greenland heights dominating the next fortnight....so unless troughs gets stuck like the end of this week, on the whole it shouldn't be too bad. I'm hopeful of a big improvement again as we head out of June and get into July.

Clear sky overnight with temperature down to 3c at 4.00am allowing some good obsevations of noctulicent clouds. the moon and according to folk from the north isles "The Simmer Dim" to the NE.

Epsom downs has spectacular views across London towards Canary Wharf and the City of air quality is good you can see all the way across the Thames Valley ! Leith Hill deep in the Surrey hills also affords amazing views North across the whole of London.

1995 anyone?

After yesterday's soggy affair, today was much better being dry, mainly cloudy with sunny intervals. NW winds moderate at first, now dead calm outside. Reached a max of 15c, temperature is really dropping fast at the moment, was 12c at 8pm and now its 6.8c. The Met Office forecast of grass frost could well be the case here at this rate. Garden now full of colour, amazing really considering the dire state it was in at the start of May thanks to the weather. One of the raised beds has been swamped by Cymbalaria muralis, a plant thug but a pretty one.

16.3c to the 20th 2.4c above the 61 to 90 average 2.2c above the 81 to 10 average ___________________________ Current high this month 17.7c on the 2nd Current low this month 16.1c on the 5th, 8th & 9th

The GEFS 12z does have some good signs, especially during early July...the mean generally indicates a typical north / south split but some of the ensembles become very summery...nationwide!..some May say that’s not realistic but at that longer range..who knows who will be right, the optimist?, the pessimist? or the realist..anyhoo, here’s a small sample.. ?!!!

Why a ridiculous interpretation? You are just using the American term that became used for a short spell in 2008. Now it is no longer used even there. You can be on holiday but also at home, that is obvious, to holiday in the UK is not a "staycation", there seems this fixation that a holiday requires international travel, it does not, it never has done. You've got the context totally wrong i'm afraid. If i have a week off work and stay at home, that is a staycation, if i have a week in the Lakes that's a holiday!!

Sorry your wrong, that is the American term, the UK staycation is staying at home. STAYCATION | meaning in the Cambridge English Dictionary DICTIONARY.CAMBRIDGE.ORG 1. a holiday that you take at home or near your home rather than travelling to…

Same thin line 02..ish and a quick time-lapse

A thin white band/line appeared sometime between 2 and 3.15. Lost track of time, quite chilly up in the hills.

Going strong.

I have wave, lvl 1-3. Happy hunting folks

Dublin Airport right now 23:11pm