Originally Posted by: Bertwhistle

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!  

Originally Posted by: Caz

Yes, I agree!  It’s great to put some reasoning and explanation behind our weather, even though I don’t understand much of it!  

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!  

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

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!

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.

Originally Posted by: Caz

Hmm!  Could we go for the ‘even more fun’ option please!  My guess this month is 15.5c and I’m in desperately need of points!  

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.

Met Office Hadley         13.3c.       Anomaly        -0.6c.  Provisional to 20th.

Metcheck                      13.42c      Anomaly        -0.73c

Netweather                   13.85c      Anomaly        -0.26c

Mean of my 10             13.85c.   Difference         -1.75c.

Met Office Hadley          13.3c.       Anomaly       -0.7c.  Provisional to 21st.

Metcheck                       13.49c      Anomaly       -0.86c

Netweather                    13.88c      Anomaly       -0.22c

Mean of my 10 stations    13.75c      Anomaly      -1.58c. 

Originally Posted by: Bertwhistle

GW any updates on your predictions for end-month, given the potential for some very warm nights? Looks like most of the heat will be in Southern areas, so some CET stations might not get such high temps.

There seems a lot of uncertainty in the models even at close range about surface temps, although they all seem agreed on 850s etc.

Massive uncertainty so any estimate is fairly meaningless at the moment.

The raw output I am looking at (which is based I think on the 0z ECM) is very uninspiring if you are after heat. The CET estimate is definitely lower than it was a couple of days ago, even when you take into account that the ECM has the heat peaking as late as Saturday. The nights are not especially warm at all for the time of year either.

If the models are to be believed I am not even sure this week can reasonably be classified as a heatwave in the UK, even in south. We might just squeeze a 30C near London which is not unusual for this time of year. Most places around 25-27C for perhaps 5 days which is very warm but not what I would class as a heatwave.

Current CET estimate is 14.46C for June but this is subject to potentially wild variations in the next few days.