Mid-May Analysis – Longer Term Thoughts…

15 May

Over the last month or two I have attempted to look at the medium and longer term trends both at the end of one month and approximately during the middle of the next month.  Through April and into May there has been clear trends in terms of the expected broader synoptic pattern, but this outlook is considerably more difficult to summarise and analyse.  The primary reason being, the longer term signals are less significant or clear.  This is often a feature of the summer months when pressure patterns become very slack and ill-defined which makes for attempting to find the broader scale patterns very difficult….However, I’ll give it a go!…

Clearly, and without question, this spring is likely to go down as being one of the most unsettled and most probably the coolest, or coldest in quite some time and clearly bucks the trend of recent springs.  With the exception of some glorious weather in March, which may offset that prediction, the rest of spring has been very wet indeed, as low pressure dominated the weather.  At the moment, despite the potential for some temporary settled conditions at times, I expect that the rest of May will remain predominantly unsettled.

The above image, I believe, will generally continue to summarize the broader synoptic pattern through the rest of the month.  There are clear signs that high pressure will become influential to the east and north-east of the UK and also perhaps to the west at times as well within the Atlantic, which may bring some temporary respite from the unsettled conditions.  However, this still doesn’t detract from the fact that the broader pattern is likely to be that of a trough over the UK and likely lower pressure overall.

The GFS ENS in particular, highlights this well also within the latest forecast chart for the 30th of May.  When looking at medium and particularly longer term, the details are sort of ignored with emphasis placed on attempting to find the broader patterns, particularly if there is consistency over a specific pattern.  This is the case at the moment.  The GFS ENS and the EC ENS both are consistent in terms of having a trough over the UK, whilst ridging within the jet stream is evident to the west and also the east of the UK and you can see this within the below image;

The other noticeable feature of the weather of late is the depressed temperatures, is this likely to continue?…The overall answer is yes, but with a likely trend in temperatures to recover to nearer average as May progresses.  What there isn’t any sign of during the second half of May is a surge or significant increase in temperatures into the very warm or hot category.  The generally unsettled theme is likely to sustain temperatures around average at best, but when compared with of late, it will feel warmer.

So in summary, despite a potentially improving picture compared with the first half of May, the second half of the month looks set to remain predominantly unsettled with further rain and showers at times and with temperatures nearer average, but with little risk of any significant or sustained warmth.

Into early June and unfortunately the scenario, at the moment, looks set to continue.  It really is near impossible to summarize the expected pattern in graphical form for early June, but the latest longer term data at the moment keeps a more negative pressure anomaly across the UK rather than higher pressure.  As a result the early expectations for the opening week of June are forecast to be for a predominantly unsettled regime to continue with temperatures near average at best.

Hopefully over the next 7 to 10 days a better understanding of what may develop into early June will develop and as a result I look forward to looking at early and mid-June more closely later in May, but for the time being it’s more of the same unfortunately…

Regards to all.



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