Summer 2016 weather

Matt Hugo's view

What does summer 2016 have in store? The TWO summer forecast will be issued in late May but throughout April independent meteorologist Matthew Hugo, BSc, FRMetS, RMet will be giving us his view on what the current data is suggesting. IMPORTANT: This may or may not correspond with the TWO view.

Overview

1) Latest seasonal forecast models have a changed signal to previous updates and of which signal a greater likelihood of a more unsettled, cooler and wetter than average summer period. 

2) There is some consistency between the EC Seasonal, CFSv2 and the UKMO GloSea5 seasonal models for slightly below average temperatures and slightly above average rainfall.

3) At this early stage the risk of a drier and warmer than average summer is low

4) Some signs for late summer in particular to be unsettled, due to some connections between a likely active Atlantic Hurricane season.

Blyskawica" by Ziemor at pl.wikipedia. Licensed under CC BY 2.5 via Wikimedia Commons

Current situation

The UK is now rapidly progressing through the spring period and after one of the strongest El Nino events in years through this past winter, of which is comparable to the likes of the 1982-1983 and 1997-1998 El Nino’s, there is some correlation and connection that supports a generally cooler and more unsettled summer for the UK. Indeed, both the summers of 1983 and 1998, but particularly 1998, were often unsettled with low pressure systems never too far away and of which produced a lot of unsettled and wet conditions across the UK. 

Summer 2016 forecast prospects

At this rather early stage of the year, there has also been a recent shift in the longer range seasonal forecast models. Within the last few months most of the seasonal models, including the EC Seasonal, UKMO GloSea and the CFSv2 were indicating the likelihood of higher than average pressure across the UK and north-west Europe in general through the June, July and August period. This, as a result, meant that drier than average conditions were being signaled too. However, more recent updates, through the middle and latter half of March, are now essentially showing the opposite scenario for the summer period as a whole. The EC Seasonal, GloSea and the CFSv2 models are primarily indicating lower than average pressure and hence a wetter than average summer and with temperatures near or slightly below average.

This change in forecast evolution from the longer range seasonal models does produce uncertainty and further model updates in the coming weeks and months through April and May are required to determine whether there is any consistency over this signal for unsettled conditions. It does, however, lend some support to the connection that summers following El Nino events, particularly strong ones, are often unsettled. It should be noted though that even during generally unsettled and potentially cooler than average summers, there is still likely to be some warmer and drier weather at times and that does need to be emphasized as, meteorologically speaking in particular, the summer period consisting of June, July and August is a very long time.

Summary

So, to summarize this initial forecast and discussion the current thinking is that some of the best summer weather may well be early on in the summer, so May and June time with then a possible progression towards more unsettled conditions overall through the rest of the summer. There are also some signals that point towards this summer period producing the right ‘ingredients’ for a far more active Atlantic hurricane season than recent years and there is a connection between an active Atlantic hurricane season and the UK seeing more unsettled conditions late in the summer through August and into September.

The most recent update of the UKMO GloSea seasonal model, from March, highlights the current predictions well.

Source: UK Met Office

On the chart note the images on the left, regarding temperature, there is only a low probability of above average temperatures, but in contrast there is a clear signal for temperatures to be below average over and just to the west of the UK. A similar pattern exists as well regarding precipitation and this emphasizes this current signal for the summer of 2016 across the UK to potentially end up cooler than average and wetter than average.

Issued by: Matthew Hugo, BSc, FRMetS, RMet