Late July and Early August 12…What’s Expected.

17 Jul

Well there goes half of July and clearly when coupled with June is half of the summer done and dusted.  It doesn’t take a rocket scientist to realise that half of the summer, at least, is no doubt wetter than average, cooler than average and most probably for many areas, duller than average given the relentless unsettled and cyclonic conditions.  At the beginning of July, in my last blog, I was looking at the month ahead and up to present the signal for cyclonic conditions, which I highlighted, has and continues to be dominant.  I did mention in my last blog of a potential change later in the month and that now looks likely.

So what has the second half of July got in store, at the moment I expect the following broader synoptic patterns to evolve;

The evolution throughout the next 7 to 14 days of July is most certainly shaping up to be one of change.  Clearly throughout the last number of weeks or more the jet stream has been either over or even to the south of the UK at times.  I continue to expect that to be the case within the short-term bringing further unsettled conditions.  However, as we progress towards and beyond this coming weekend there is a clear sign for the jet stream to retreat towards the north and north-west of the UK.  This is forecast to allow the high pressure that has been bringing many central and particularly southern areas of Europe some glorious summer weather to date, to influence the weather further north.  It also gives the opportunity for the Azores high pressure to come into play as well.  This can be seen on the below GFS ENS chart for example;

Note on the above image how low pressure declines to the north of the UK, whilst higher pressure is far more influential across a large portion of Europe, with the exception of perhaps say Scotland and then more particularly Scandinavia.  It is this evolution which I expect to take place throughout the remainder of July which, without question, will signal an improvement in conditions across the UK than compared with of late, especially across England, Wales and perhaps Ireland.  The crucial and still uncertain area of the forecast however, is just how influential will the high pressure across the UK become?…The reason why this is crucial is because if the main area(s) of high pressure remains to the south or south-west of the UK this wouldn’t signal a nationwide improvement in conditions, with further unsettled conditions possible at times in the north and west.  However, some of the forecast models (namely the ECMWF) continues to show high pressure engulfing most of the UK later in July.  At the moment I don’t support such a large pressure rise across the UK.  It is possible, but unlikely at this stage, but clearly this area of the forecast is very important and will need addressing on a more short-term basis in the next week or so.

So in summary for the remainder of July, an improvement is likely…High pressure looks likely to influence the weather more, particularly across England and Wales and especially across southern areas of England. Scotland and Ireland may well remain more unsettled at times, but as I have highlighted above this is heavily reliant on the finer details.

So, a change for late July, does August look like being sunny, hot and high pressure dominated?…

Unfortunately I don’t believe it will be, or at least not the first half of the month.  Here’s my expected broader synoptic pattern into early August;

At the moment I expect lower pressure to return to the UK and unfortunately bring a mixed outlook.  Clearly the details surrounding the first half of August are highly uncertain, but I have attempted to highlight in the above graphic what I believe will happen and that is for southern and eastern areas of Europe to continue as they have done so far this summer and be dominated by high pressure and warm conditions.  Low pressure and a general trough-type pattern, I believe, will return to the UK and many other northern areas of Europe during the first half of August.  The signals are relatively weak, I have to admit, so confidence levels aren’t particularly high, as they shouldn’t be really for a longer term outlook.  But that being said, up to date the information which I have analysed and studied to produce these longer term thoughts and analysis have been more right than wrong, so at the present time I stand by my suggestion of cooler and unsettled conditions returning.

The longer range GFS ENS also highlights this broader pattern as well and matches the above graphic;

Any high pressure in late July declines to the south or south-west of the UK and the negative pressure anomaly to the north of the UK becomes more extensive once again.  Clearly parts of the south of the UK may have some better weather at times, but the broader scale pattern brings back the more unsettled, westerly regime to the UK and other northern areas of Europe.

So, here’s to late July and hopefully some long-awaited better weather, but at the moment it may well have to be a case of make the most of what we get within the next 7 to 14 days as early August may well not continue the improvement and actually head back to what we have had throughout the summer so far….unsettled conditions.

Regards to all.

M.

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