The situation is very much 'poised' as we head through the second half of June and into early July.
Over the past month, tropical forcing has behaved quite nicely, with well-timed tropical forcing first setting up the long spells of mainly fine weather during May's second half (but with the notable exception of many eastern coasts!) and then mitigating the extent of unsettled conditions and southerly movement of the jet during June so far.
You see, with respect to having settled conditions across the UK, we essentially went from mostly helpful forcing to a mix of helpful and unhelpful forcing.
Now, though, it's 'crunch time', as the unhelpful forcing (i.e. lingering La Nina-like atmospheric tendencies) has an opportunity to take over and send our summer markedly downhill - something a few model runs have explored during the past week.
However, it just so happens that the state of the tropical Pacific Ocean is undergoing changes toward a more Nino-like state, and this is encouraging more counter-Nina events (such as westerly wind bursts (WWBs) i.e. weakened or reversed trade winds) to manifest compared to what might have been the case. One of those WWB taking place in the next few days will help to move the ridge back east next week after a brief retraction west that owes its occurrence to that Nina-like tendency we'd like to see the back of (unless for whatever reason - e.g. medicinal - you're not a fan of settled summer weather, that is!).
Unfortunately, we can't yet be sure that the Nina-like tendency won't fight back again and force the high pressure to locate west of the UK again by next weekend or soon after. GFS/GEFS continues to toy with this idea but ECM/EPS doesn't seem so interested.
This time last year, we were enjoying the fruitful outcomes of some very helpful tropical forcing with the Nina-like tendencies of the preceding winter broken, but then the tropical Pacific Ocean took on a Nina-like pattern, allowing the Nina-like tendencies to recover and then exert a strong enough influence on our weather patterns to steadily deteriorate conditions during July, resulting in a very westerly, changeable August that was uninspiring for the majority. In fact, I can't remember any weather highlights at all between mid-July and early September!
This year, the oceanic trend is in the opposite direction, so there's reason to be optimistic about the July prospects this year, but until if and when we see the La Nina tendencies fail to put up a significant fight during the next lull in helpful, Nino-like forcing (such as the WWBs), it's best to add in 'cautiously' before 'optimistic'.
Basically, it's the ENSO World Cup taking place on a neutral stage, and those who enjoy fine summer weather should throw their support behind El Nino team 
.
p.s. Come On England! 
Originally Posted by: Stormchaser