Mild end to the month

After the cold night on Monday, Tuesday saw the thermometer rise to 11.1c being 1.1C above the average. There were two very brief rain showers at 22.15 and 06.45 on Wednesday morning that produced 1.7mm of precipitation that took the monthly total to 18.6mm. This total was 73.1mm below the 37-year average and gave us the driest November I have recorded since the station was set up on 1984.

Wednesday in the early hours saw the thermometer again fall away to give a minimum of 6.6C, which was almost 3C above average.

November 2021 Review

Storm Arwen struck at the end of a record dry month

The month began with a dramatic change in the weather, out went the wet and mild weather and in came a cool airstream from the north. There was a ground frost on the 2nd and a sharp air frost in the early hours of the 3rd when the thermometer dropped to -2.3C. Daytime temperatures also fell away with a peak of just 8.4C on the 4th being 1.6C below average with wind chill in effect, making it feel at least 1C cooler outside in the breeze.

A distinct change in the weather pattern saw mild south-westerly breezes arrive on the 5th with subsequent days producing a maximum above the average, the warmest day occurred on the 9th with a maximum of 14.7C. This peak was 4.6C above the 37-year average but more significant was the following minimum overnight of 10.8C, which was 7.0C above the average minimum and 0.7C above the average daytime maximum.

The misty, humid and murky conditions continued until the 19th with much low, thick cloud. The fourth sunless day occurred on the 20th. I recorded a run of fifteen consecutive days, from the 6th to the 20th, when the maxima were above average, often as much as 3C or 4C.

The arrival of a cold front late on the 20th brought another dramatic change in our weather. Gone were the mild, moist days and in came the wind from the north and northeast on subsequent days that saw the maximum temperatures fall by over 7C. The brisk northerly wind on the 21st brought wind chill for the first time this autumn when an ambient temperature of 6.6C felt more like 4C outside.

Frosts returned during the early hours of the 22nd when a ground frost occurred producing a coating of white ice first thing.

Storm Arwen struck late on the 26th with sleet in the rain early afternoon. However, the full effects of the storm were not felt until just before midnight when the wind began to strengthen significantly with a maximum gust of 42mph at 06.17 on the 27th. During this twenty-four hour period 4.8mm of precipitation was recorded breaking the run of 13 consecutive dry days. This was not a record gust for November as a peak gust of 53mph was logged on the 14th in 2009.

Snow was observed in a brief rain shower at 07.40 on the 27th. However, more continuous and heavy snow began at 09.30 and continued until 10.45 leaving a light covering but due to the residual warmth in the ground, promptly melted. During this period the temperature dropped from 1.8C to 0.7C but outside the strong northerly wind made it feel more like -2C due to wind chill.

Snow has occurred in November before with one day each in 2015 and 2016 also 2 days in 2005.

November was in direct contrast with the very wet October. There were 19 dry days with a run of 13 consecutive dry day from the 13th to the 25th.

Although the first half of November was warm the frosts and cold winds later produced a mean temperature that was 0.3C below the 37-year average.

The total rainfall of 18.6mm was a record for this station that started in 1984. The monthly total was just 20% of the long-term average for November, or 73.1mm below, with the wettest day on the 26th only recording 4.8mm. The loss of equivalent rainfall due to evaporation from ground sources and plant life amounted to 12.5mm, which left a net gain for the month of just 6.1mm. There were 19 dry days during the month that far exceeded the average of 12.
A notable feature of some past months in 2021, and also November, were the many days with minimal wind movement. During November there were 9 days when the maximum air movement, couldn’t call it a gust, at head height was in single figures, the 10th being an example with the highest of just 5mph. During many nights and some days the wind dropped out completely for many hours. September the 6th was exceptional when no air movement was detected for twenty-four hours at head height. My very high anemometer, positioned some 3 metres above our building ridge height, recorded just one isolated movement of 8mph.

Curiously, Britain has been in a wind drought for several months this year. There was a distinct lack of wind from April to September, despite the occasional gale, which made it the least windy April-to-September over most of the UK for 60 years, thanks to various high pressure systems that effected the UK.

Europe also had a long periods of low wind speeds over the summer and early autumn, all of which had an enormous impact on wind-power generation. The experts state that this is another example of the extreme weather events occurring in the world.
The UK should brace itself for a wet winter with an increased chance of flooding, according to the forecasts from the Met Office. They predict that the outlook shows that there is an above average chance of the winter being wetter than normal over the three months from November to January with the wetter conditions most likely in January next year and beyond. November proved the forecast wrong but what will the two remaining months of winter produce, I wonder?
Meteorologists said a range of “global drivers” including lower than average sea temperatures in the tropical Pacific mean the coming few months could be milder, windier, and wetter than a normal British winter, this could bring disruption including flooding and storm damage the Met Office warned.

Autumn 2021

The mean temperature was 1.2C above the 37-year average and the fourth warmest I have recorded. The record was set in 2006, which was 2.1C above the average.

The three monthly rainfall total amounted to 216.7mm being 90% of the long-term average. The extremes were in 1985 with 116mm and 2006 with 401mm.