Wychwoods’ weather summary for 2019

The weather during 2019 has been hitting the headlines for its extremes in both temperature and rainfall, but if you were to take the summary of the Wychwoods for 2019, you would not be able to see the enormous variations that we had that culminated in a fairly average year overall. Variety is the only word that comes to mind with only two elements of weather that have not been experienced this year: a substantial snowfall combined with a prolonged cold snap.

We all remember the hot days in the three consecutive summer months of June, July and August, but we tend to forget about the cold and damp days that have been particularly prevalent this autumn. This coincided with the wettest periods I have ever recorded during my 24 years of local recording over a four month autumn period with nearly 400mm of rain, which is well over 50% of the annual total recorded for the whole of 2019.
We started the year quite dry and were still only at 77% of normal rainfall at the end of May, and although June was slightly wetter than normal, most the rain fell over four days (7th, 10th, 13th and 25th). July and August continued the dry theme until we encountered the last two weeks of September that set the scene for the rest of the year: wet.

During the entire year we only encountered one little snowy patch right at the end of January and the beginning of February which melted within a couple of days. A couple of mornings when a light sprinkling occurred but that was it for 2019.

During the summer we experienced four days with the temperature exceeding 32°C. All the signs were there for a cold winter to follow, with a prevalence of a ‘blocking’ high pressure zone to the east of us, and creating a situation that got the press quite interested in what the future winter had in store for us. In fact, right up to the first week of November, the signs were still there for a very cold winter for 2019/ 2020, with the geese putting on weight and eating well with their feathers thick for warmth backing up the story. Then, suddenly, around the 20th November, they just lost their appetite and their feathers became less dense. Something had changed….

The jet stream that had been weak and taking a more southerly trajectory strengthened and moved north with a secondary stream splitting off towards the Mediterranean. The signs of an SSW (Sudden Stratospheric Warming) that had been in the background for most of the summer to the east of the UK disappeared overnight; this together with a pool of warm water south of Greenland dissipating, meant that we were looking at a typical fast-moving westerly airflow that is so common of warm winters, establishing itself virtually overnight. The press went quiet and the talk of a bitterly cold winter disappeared off the radar, replaced with Brexit and elections again!

Weather Table
The trend over the past 25 years in the Wychwoods has been a small rise of about 0.43°C, with annual variations but certainly a tendency that is being experienced around the globe. This is not exceptional, and 2019 being just 0.558°C above the Central England average of 9.84°C, but it can mean the difference between having long periods of bitter easterly winds in the winter to experiencing a spell of strong warm south-westerly winds that are becoming more common. This is not to say that we shall not have another ‘Beast from the East’ but the continent and particularly Siberia must get significantly colder than it has been for a couple of years for this to happen.

Record-breaking weather
A number of weather records were set in the UK during 2019. Most notable was the new highest temperature set at Cambridge Botanic Garden on Thursday July 25th. The 38.7C beat the previous 38.5C which was recorded at Faversham, Kent in 2003.

The February temperature record also was broken with 20.6C being reached in Trawsgoed, Wales on Monday 25th February. It easily beat the 19.7C reached in London in 1998. The winter of 2018 – 2019 had been tipped by many to be colder than average, but it ended up as another mild one.

In the Wychwoods we achieved 33.9°C on 25th July and 18.2°C on 26th February – still quite exceptional, and I firmly believe that these figures will be exceeded in the next few years.

I talked about the ‘evapotranspiration’ in my last piece, which is basically the combined process of water surface evaporation, soil moisture evaporation and plant transpiration. It is important because this is normally very close to the amount of rainfall at a given place during the year. In 2019, we had over 80mm more rain than we lost through evapotranspiration, meaning that the water table rises and we are more susceptible to flooding as the ground is more saturated than we have seen for well over a decade, and in some parts of the UK it is at a record level of over 250mm difference.

Future weather
It is now agreed that any weather forecast that is beyond 10 days loses its accuracy exponentially. Forecasters look for trends but are rarely right, and we must all be aware of the increase in global temperatures over the past 80 years and particularly in the most recent 20 years. The eleven warmest years in the UK have all occurred since 2002. Everything meteorologically is supposed to be cyclical, but then we were not cutting down a football-pitch sized area of rainforest every second. Basically, trees breathe in carbon dioxide and breathe out oxygen.

2020 and beyond
With 2019 being fairly average but with some interesting contrasts, I think that we can expect more of the same but potentially with a move towards a slightly more ‘continental’ type of weather, featuring some warmer summers and potentially colder winters. But where is that damn jet stream going now?!

John Miskin

February – March 2020