Met Office Hadley         12.8c      Anomaly      -0.9c. Provisional to 14th.

Metcheck                      13.03c     Anomaly       -1.12c 

Netweather                   13.47c     Anomaly       -063c

Mean of My 10 Stations   13.23c    Difference     -2.1c.              

 Temperatures should be on the rise Tomorrow onwards.  

So... the low for Wed has adjusted to one that stay just weak and far south enough to minimise the warm air incursion, but just developed and far north enough to bring another spell of showery rain that we could really do without.

Just as with last week's system positioning pretty much optimally for low temps and widespread atmospheric moisture release via cooling, there is an inescapable sense of extremely hard luck for us Brits this June.

You see, our weather patterns are only guided on a broad scale by the various forcing mechanisms; the exact intensity and path of systems comes down to small-scale fluctuations of a chaotic nature. Chaos is closely tied to luck, hence the feeling of poor fortune.

This coming week could so easily have been warmer. Admittedly not drier with that, but a day or two in the mid-20s would at least have been something to smile about, while we await a more sustained improvement in conditions.

There are still signs of high pressure gaining the upper hand by next weekend from some models, but the track of the midweek low brings a lot of polar maritime air in, keeping temps unusually fresh for the time of year. The CET may struggle to make it into the 14s at this rate - something that seemed inconceivable when studying the various indications from modelling and climate theory in the last week of May.

2019 has so far been the year of failed long-signposted major pattern shifts. It really does appear that we've changed the very workings of the climate to something new that defies the old methods of anticipation. It's fascinating, but in a dark light.

Great post as ever SC.

One of the things I love about the weather in this country is just how unpredictable it is none of us saw how cool and wet this June would be neither did any of the Pros. A cet under 14c looks likely  now maybe even under 13c.  And also perhaps a record breakingly wet month as well.

Not everywhere has been really wet though just recently, as I have explained in a post which I submitted to the summer general discussion thread during this morning. For here ever since the middle of April 2018, we have never been able to get any sustained wet spell which lasts for over a week or so. Even during this week which is now ending, there has only been two days throughout the entire week where it has actually rained. We started this week in a dry spell, we are now ending this week in yet another dry spell and this week hasn't been all that much wetter than average overall here.

For where I live, our biggest issue has not been so much with the amount of rainfall which we had, as it has been with the fact that we experiencing some ridiculously cold daytime temperatures at times and more importantly, a chronic lack of sunshine during this month so far. We have only had two completely sunless days during this month so far but at the end of yesterday, we had only had just over a third of our average amount of sunshine for this month even though we have now reached the halfway point in this point.

During that time, there has only been one day which we can actually regard as being a decent, sunny day. As far as the temperatures are concerned though, it has been very much colder than average here. Even in this part of Scotland where I live, any given summer month would be expected to have at least one day within it where the temperature reaches or gets to above 20 or 21°C and yet, we have barely come even close to that during this month so far let alone actually reached those sorts of values.

Furthermore, we have had a number of days just recently where we have been struggling to even get into double figures. The result of this is that for here, our daytime maximum temperatures are currently running about 1.9°C colder than the 1981-2010 June average with our average temperatures running at around a degree colder than that  average which in turn, is more or less in line with the latest CET anomaly.

Met Office Hadley         12.9c.      Anomaly      -0.9c. Provisional to 15th.

Metcheck                      13.02c      Anomaly      -1.13c

Netweather                   13.48c      Anomaly      -0.63c

Mean of my 10 stations    13.16c.  Difference    -2.17c.

Thanks - sadly I can't enjoy the unpredictability like I used to now that I've become one of those 'Pros'. One of the worst things about being involved in longer-range guidance is knowing so much about what could have been, when the reality is one of the least desirable outcomes.

During the final week of May, the following signals were at hand for June:

• Warm opening couple of days, then near-average remainder of week (for day + night combined)


• Slow-moving low near or over the UK for at least first half of 2nd week of month. Origin SE of the UK so movement through France more likely than across UK, with warm but showery conditions affecting much of England and Wales.


• Arctic blocking reducing for 2nd half of month, and NAO moving from negative to positive. Signs of slow-moving ridges across NW Europe; predominantly warm pattern for the UK. Some thundery interludes likely.

The way that low moved last week was truly exceptional. Historically, our poorest runs of June weather have come from the Atlantic, not mainland Europe. Even more extraordinary was how the low positioned such that it was able to draw cool maritime air off the Atlantic to mix into the very warm from Europe before any of it reached the UK - except briefly the far SE on the Tuesday. The more typical outcome would likely have left the CET somewhere in the 14s as of mid-month.

Now, looking forward, we're seeing the long-anticipated waning of Arctic blocking looking less and less convincing, and there's signs that the NAO will be equally 'disobedient'; the ensembles are now favouring a continued negative state overall.

A big factor behind the Arctic blocking and NAO issues is some tropical thunderstorm activity in the western Indian Ocean. This was expected to be outgunned by activity moving into the Pacific from the eastern Indian Ocean (i.e. the MJO) but instead it's of similar intensity, and a few days ago, it even gave rise to a rare June tropical cyclone that tracked close to the west of India. 

Such Indian Ocean sourced interference has been witnessed a couple of other times in the past couple of years, derailing the August heat and December cold last year.

Unfortunately, long-range modelling is currently very unreliable for tropical thunderstorm patterns, with even short-range predictions for just 3-5 days ahead often significantly wide of the mark. So there's no way to reliably anticipate when there's going to be interference that begins nearly a fortnight into month, like it has in June 2019.

Last week's unusual low behaviour pretty much ruled out a CET in the high 15s or above.

The failed positive NAO switch for 2nd half of June now has now stacked the odds against a CET higher than the mid-14s.

Any bets on a scorching July? 

Thank You Stormchaser. 

Your posts are always so informative.

Met Office Hadley          12.9c.      Anomaly      -0.9c Provisional to 16th.

Metcheck                       13.15c     Anomaly      -0.99c

Netweather                    13.53c     Anomaly      -0.57c

Mean Of My 10 Stations   13.42c     Anomaly      -1.91c.  

SC I love the global links in the weather that you fix in to the bigger picture; and even the NA references give me a clearer view of what's going on. Excellent analysis. 

I’ve said this before but it’s worth saying again, SC and GW both make truly excellent contributions to this thread, in different but complimentary ways!  We’re lucky to have them both!  

Met Office Hadley             13.0c        Anomaly       -0.8c. Provisional to 17th.

Metcheck                          13.28c       Anomaly       -0.86c.

Netweather                       13.67c       Anomaly       -0.44c

Mean of my 10 stations        13.49c       Anomaly       -1.84c.     

I would agree with this wholeheartedly; one of the best threads on TWO (opinion).

Met Office Hadley          13.1c.     Anomaly    -0.7c. Provisional to 18th.

Metcheck                       13.36c    Anomaly    -0.78c

Netweather                    13.74c    Anomaly    -0.37c

mean of my 10 stations 13.7c.   Difference   -1.63c. 

Thanks for all of the kind compliments, it's always uplifting to see my thoughts and analysis received so positively .

Some, well, interesting model runs have been rolling out since I made that last post. Especially the past couple of sets! However... here's some sobering facts:

Even with things falling into place for such a big draw of heat as the 00z ECM shows, the CET recovery only makes it as far as the LTA as of 28th.

The less optimal GFS (surface flow stays off the North Sea until right before the breakdown, keeping a lid on temps) only just makes it into the 14s as of that date.

On the other hand, that'd be one heck of a recovery after such an unseasonably cool majority of the month.

Rarely do these lows developing west of Iberia behave themselves, though. It's not going to take much of an adjustment east to keep the heat intrusion relatively small, or north to break things down more quickly.

Then again, we did very well in late Feb (and then some!), and the FV3 06z, rolling out as I type this, is looking better-aligned for the heat draw than the 00z did, as of Monday 22nd.

By Friday, we should have a pretty good idea which way this is going to go. It's going to be a tense modelling ride!

Nice post there James and well described as well.

Met Office Hadley           13.3c.      Anomaly      -0.6c. Provisional to 19th.

Metcheck                        13.42c     Anomaly       -0.72c

Netweather                     13.42c     Anomaly       -0.29c.

Mean of my 10 stations      13.69c     Difference      -1.64c.

Well, all these toasty model runs are really starting to raise eyebrows. Even the so far reluctant UKMO model gets the 20*C 850 hPa temps in play by noon Wed, even if it is only across the far SE at that time.

So just for fun - if the heat sticks around as long as the FV3 12z has it doing, then even using its raw numbers which could well be underplaying the maximums by 1-3*C, the CET estimate performs an almighty climb to finish at 14.8*C.

That really would be a novelty, recording a slightly above average month after so much cool and rainy weather.

For even more fun - a fair few EPS members keep the heat around a day or two longer than that .

Now we're getting silly though; best to focus on the opening stages for now, and keep a close watch for convergence lines as they threaten some nasty thunderstorms with max temps not faring so well.

Yes, getting above average is a tall order but do-able if the hot models have it right and providing the heat gets to all three stations!

I think ECM heard your plea Caz - even the raw data with the usual underestimation (yes, ECM has this habit too) gives me a final CET estimate of 14.9*C!

I've mixed feelings about that though, as the heat & humidity combination Thu-Sat looks a bit dangerous (around 70% relative humidity by day with maximums as high as the mid-30s, even more humid by night, with minimums widely high teens, locally low 20s).

One more below average day before things start to warm up.

Latest estimate from my calculations is for the CET to finish at 14.57C. That is potentially quite conservative. If we get a direct hit from the plume then something closer to 15C is likely. But bear in mind the hottest temperatures are likely to be south of the CET area.

As of today my calculations have the CET at exactly 13.00C. Currently more than 1C below average. But it now looks like we may finish just slightly above average.

Thanks for the update GW 

Interesting divergence of the models this morning.

All are still bringing in a big blast of heat, but now FV3 is going for a more direct import from the south as soon as Wed, with high 20s to low 30s across the CET region, while ECM keeps a flow off the North Sea going until late Thu which keeps the maximums down to mid-20s at most for the CET region, before they rocket into the high 20s to low 30s for Friday, and then it all implodes on Saturday.

These looks to be within opposite ends of the range; FV3 among the hottest CET outcomes and ECM among the least. 

UKMO sits at halfway house for 00z Wed, but by 00z Thu is much more like FV3.

Meanwhile GEM is more like ECM.

So no clear majority here - but perhaps a slight lean toward FV3 over ECM.