Summary for November and Autumn 2016
November
The month began with mostly dry days and daytime temperatures around the average for November with air frosts on seven successive nights. This changed dramatically from the sixteenth as winds backed into a westerly quadrant with very wet days, the wettest being the 19th with 25.2mm
The period from the 16th to the 22nd brought 70% of the month’s rainfall. It was all change again from the 23rd as an anticyclone built, bringing winds from the northeast. The drier air from this direction gave us eight successive days without precipitation.
The predominant wind was from a northeasterly direction on 10 separate days, mostly at the end of the month. It was a breezy month with maximum gusts into the 20’s on 16 separate occasions with the strongest gust of 37mph on the 17th. The sunny days at the end of the month brought quieter weather with a very calm day on the 30th giving a maximum gust of just 6mph then after midday it dropped out almost completely.
The rainfall total was 117.1mm being 128% of the November mean or +25.5mm. Although it was a wet month the records show that 1990 was the driest November since 1984 with 27.8mm and by contrast 203.5mm in 2002.
It was a cold month giving a mean 1.6C below the 32-year average, being the coldest November since 2010. There have only been five colder Novembers since this station began in 1984.
The occurrence of air frosts in November has been a declining feature. However, 2016 gave us 13 nights with an air frost, the highest total since 2005, when the average is 6. There were several sharp air frosts in the second week but on the morning of the 30th the thermometer had dropped to -7.3C, which was the coldest November night since 2005.
By the morning of the 30th the cold days and very frosty nights meant that the ground had frozen down to a depth of 5cm, with a reading of -0.5C.
There were 54.8 hours of strong sunshine, which is far greater than that recorded in 2015 and 2014, which gave us 16.4 and 41.4 hours respectively. There were eleven days when no sunshine was recorded due to the persistent low heavy cloud. But, there were several days, principally at the end of the month, when we had beautiful blue skies with almost continuous sunshine. The last three days produced 6.2, 6.1 and 5.3 hours respectively.
On the 1st and 2nd the days began with fog, down to 150m and 200m respectively.
Just before dawn on the 18th there was a light fall of wet snow.
Autumn
The three months from September to November produced contrasting temperatures. September was above average, October about average followed by the cold November. Overall the mean was close to the 32-year average being 0.1C above. However, this was the coldest autumn since 2012.
The rainfall total for the three months was 206mm, which is 86% of the long-term average or 35mm below the average. It was the driest November since 2011. It is interesting to see the range of rainfall for this month over the last 32 years. In 1985 we had the driest November giving just 116mm and the wettest in 2006 with 401mm.
The total hours of strong sunshine for these three months was 238 hours. This was 26 hours greater than the average for the previous two years when this instrument was installed.