News and information

Winter 2016/17

Tentative weather prospects


27/06/2016

UPDATE 15/09/16 now online

UK winter 2016/17 weather forecast indicators

 

It's a long way off but are there any early pointers to how winter 2016/17 may turn out? Independent meteorologist Matthew Hugo, BSc, FRMetS, RMet takes a look at what the latest data is suggesting.

Overview

After an exceptionally unsettled winter last year, primarily due to the influences of El Nino and the QBO (Quasi-biennial Oscillation) phase, the coming winter is likely to have different ‘foundations’.

There is some uncertainty over the likely phase of ENSO (El Nino-Southern Oscillation) for the winter period, but a repeat of last year's ‘strong’ El Nino is not expected.

At the moment ENSO-neutral conditions are in evidence, if not just with a slight trend towards La Nina.

La Nina is favored to develop during the rest of the northern hemisphere summer, with an approximate 75% chance that this will be maintained through the autumn and winter.

When coupled with an easterly phase of the QBO the coming winter may turn out significantly different to the last one.

Snowman

Discussion

We will start by briefly looking back at the winter of 2015/2016 as a comparison to the coming winter period. Last winter produced one of the most potent and powerful polar vortex in many years. This helped produce a relentless period of very wet, very mild and very windy conditions across the UK and a distinctly +NAO (North Atlantic Oscillation). During last winter we were entering into one of the strongest El Nino events in many years and this, without doubt, had some influence on the northern hemisphere’s weather patterns. Equally important was the westerly phase of the QBO. This combined with solar activity and El Nino helped produce a distinctly cyclonic and unsettled winter period with little cold weather.

Whilst looking ahead to the winter period at this time frame will produce more questions than answers, what can be looked at are ENSO and also the likely phase of the QBO. These variables go through broader changes and evolutions making it is possible to predict with some degree of accuracy the likely patterns for this coming winter.

After the very strong El Nino of last winter we have now progressed towards near neutral conditions and with an on-going trend towards La Nina in the coming months. At the moment some of the main forecast models (see below image) highlight that through the winter period a weak La Nina is expected to be in evidence. Clearly this will be in complete contrast to the ‘strong’ El Nino of last winter.

ENSO

Whilst there is always an uncertain connection between ENSO and the weather across our region of the northern hemisphere, it is expected that a weak La Nina event wouldn’t aid in strengthening the northern hemisphere’s polar vortex like the El Nino event of last year did. A weak La Nina can promote more in the way of northern blocking through the winter period, but this is certainly an uncertain prediction at any time due to other factors.

The QBO (Quasi-biennial Oscillation) phase this winter is expected to be opposite of last year with an easterly phase expected. Without going into the details of the QBO too much, essentially think of the QBO phase as a system that can facilitate the development of a more potent northern hemisphere polar vortex. A westerly phase QBO essentially adds more ‘fuel’ to the overall winter-setup, whilst an easterly phase of the QBO is known to promote a more disorganized polar vortex. The more disorganized the polar vortex is through the winter period the greater the likelihood of colder outbreaks and less in the way of stormy conditions.

Sunspot activity has been declining since a peak around the winter of 2014/2015. It is no surprise that the severe winters around 2009 and 2010 did coincide with a particularly noteworthy solar minimum, as can be seen on the below graphic. Whilst the connection between solar activity and winter weather is a vague one the general decline in solar activity is set to continue through this coming winter period.

Sunspot numbers

Summary

Early indications suggest the coming winter may be significantly different to the last one. The combination of lower solar activity, a weak La Nina and an easterly QBO phase may favour a less cyclonic pattern and perhaps increase the risk of colder outbreaks.

RECENT WEATHER NEWS


LATEST NEWS

Dry and bright in most of the UK

NEWSLETTER

Get weather updates by email

Register now

TODAY'S WEATHER

7 day charts

RECENT FEATURES

Spring 2021

Air mass temperatures since 1961

Winter 2020-21 forecast

Winter 2020-21 final preview

Weather time capsule