I thought that I’d look back at the three month outlook for autumn 2024 [SONSON Meteorological Autumn - September, October and November] issued by the UKMOUKMO The Meteorological Office is the United Kingdom's national weather service. It is an executive agency and trading fund of the Department for Business, Energy and Industrial Strategy on the 27 August. The outlook is split into three distinct areas, temperature, precipitation and wind speed. It’s relatively easy to assess how accurate the outlook was for temperature and precipitation, but not so for wind because the UKMO don’t issue monthly gridded mean wind speed data. They must have this data because the three month outlook itself contain three month anomaly charts for wind speed. The one climate statistic that they did omit is sunshine, important not only summer, but also in autumn and winter, as this gloomy November highlighted only too well. Here’s a table of climate statistics for the UKUK The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and Northern Ireland. for the three months that make up meteorological autumn and anomalies for temperature, precipitation and sunshine.
How accurate was the forecast of temperatures?
The outlook stated that there was a 40% chance of it being a warm autumn, with a fifty-fifty chance of near average temperatures. In the end, the mean temperature for the three months that make up meteorological autumn was +0.3°C above the 1991-2020 long-term average, so it was only marginally warmer. WRONG, autumn was not noticeably warmer than average, although they were right about ‘cool spells’ later in the season, but cold spells towards the end of autumn are far from uncommon.😉
How accurate was the forecast of precipitation?
The outlook stated that there was a 35% chance of autumn being wet, with a 55% of it being near average. In the end precipitation in autumn 2024 ended up 89% of the long-term average. So a drier, rather than a wetter autumn. Despite flooding from storm Bert, the first half of November was very dry across the whole country, WRONG.
How accurate was the forecast of mean wind speed?
The outlook stated that there was a 35% chance of autumn being windier than average, with an increased risk of stormy conditions. As I said earlier, there’s not an easy way of measuring the accuracy of this one. There were three named storms during autumn, one of them named by the KNMI, the other by Met EireannMet Éireann Met Éireann, the Irish National Meteorological Service, is the leading provider of weather information and related services for Ireland.. The first half of November was anticyclonic which would have reduced the mean speed for the whole of autumn a fair bit. UNDECIDED.