Weather in the Wychwood: September/October 2020

What makes the weather so interesting is that no two days are the same in the world of meteorology, let alone two months when comparing with other years.

I will attempt to compare the two months against the averages that the Hadley Centre Central England hold going back to the 17th century. What we are seeing is both the monthly temperatures and rainfall levels have increased over the past decade or so, and although global warming is having an effect, there were far wetter and warmer periods in both the 18th and 19th century that lasted for several decades in their own rights. Back to the here and now, overall both September and October were within 0.3°C of the average with September slightly warmer and October very slightly colder, with no air frosts being recorded and only one ground frost on 28th September with the air temp of 0.3°C and the maximum temperature recorded was on 15th September with 27.0°C.

Rainfall was interesting as September was heading towards being the driest on record until the last two days of the month when 26.6mm of rain fell giving a September total of 37.6mm (average 55.5mm). October was just plain wet, and the rain that fell at the end of September continued virtually to the end of the month with 124.2mm recorded (average 61.5mm) making it the wettest since 2004 when 125.4mm of rain fell.

October was the first month since February that we have experienced more actual rainfall than we lost through evapotranspiration, meaning that we have started to see the water table rise for the first time this season. This past October has been one of the cloudiest we have had for many years with 24 days recording rain and only 7 dryish days. It is always worth listening to the weather forecasters when they start talking about the jet stream, as that in a nutshell controls our weather in the UK.

I hope to be doing a summary of 2020 for the next edition, but if things continue as they are, it will turn out to be warmer and slightly wetter than the long-term average.

Future prospects for the 2020- 2021 Winter

At the moment there isn’t a conclusive signal for winter 2020-21 but the seasonal models are quite bullish about it being milder and wetter than average.

The prospects for the QBO (Quasi-biennial oscillation) and NAO (North Atlantic oscillation) are uncertain and on balance they do very little to suggest an increased chance of a cold winter. The possibility of a weak La Nina may be a factor which increases the likelihood of a colder winter, and the same is true of the phase of solar cycle 25. Nonetheless, both of these factors are tenuous at best. Please Google the known meteorological influences as outlined above as the editor forbids me to bore you further!   

Recent climatology favours milder conditions and the last two winters have both delivered big positive temperature anomalies with little snow in Central England, and through 2020 warmer than average months have been a lot more frequent than cooler ones.  

Therefore, it is my belief that we are in for another fairly mild winter, unless of course we see Central Europe cooling down a lot quicker than it has in the past few years.

John Miskin

April-May 2021