Author: Eric Gilbert

Thursday brought us 8.0mm of rainfall, very heavy before and just after dawn on Friday. This brings the December total to 39.5mm when the average for the whole month is 90.0mm.

The flow of vey mild, moist Atlantic air continued with little variation in temperature. The maximum was 12.2C and only dipped to 11.5C overnight.

Friday arrived with a very wide weather front crossing the area and very heavy rain.

Update on Friday at 16.35: more sunshine at last with over 3 hours although the temperature has been falling all day from peak of 11.7C at 08.00 to currently 6.2C.

Wednesday was dominated by thick, low cloud all day with rain starting just after noon producing 6.7mm of precipitation bringing the December total to 31.5mm. Due to the mild Atlantic air the thermometer returned a maximum figure above average (+4C) of 11.8C.

No sunshine occurred and the UV level was 0, not surprisingly, the first day that this has occurred in December.

Thursday started dry with the cloud base a little higher after a very mild night when the thermometer did not drop below 9.5C (at 00.20), which was 7.6C above average.

Tuesday saw the thermometer struggle to a maximum of 6.1C at 13.27 during the 4 hours of sunshine in the morning. This was 1.7C below average and the first below average day for a week. However, advancing cloud before noon gradually blotted out the sunshine with rain starting late afternoon.

Another 5.2mm of precipitation was recorded yesterday, which brings the December total to 24.8mm. We have now had eight successive days with significant rainfall after six months with below average rainfall.

Light rain continued throughout the night and at dawn the cloud base was low with more light rain and drizzle.

After a low of 4.1C at 23.05 the thermometer eased upwards with a significant rise just before dawn so that at 08.00 the thermometer read 8.7C.

Update on Wednesday at 15.00: persistent rain arrives just after noon from a wide and slow moving weather front extending from northern France to Scotland. Southerly mild, moist air mass raises temperature to a maximum of 11.8C, being 4C above average.

After a few minutes of brightness on Monday morning the very heavy showers built up and continued for most of the day producing 9.9mm of rainfall.

As we were still under the influence of the mild Atlantic air the temperature rose a little, again above average, to a maximum of 11.1C.

Late morning the wind began to veer from the southwest into the northwest bringing a slow drop in temperature.

Overnight a clearing sky meant that a slight air frost occurred with the thermometer dropping to -0.2C.

Tuesday arrived with a mostly clear sky and sunshine as soon it it got up with the promise of much more than the 9 minutes that were recorded on Monday. Thanks are due to the temporary ridge of high pressure that has been building for the last twenty-four hours with a 24Mb rise.

Update on Tuesday at 17.40: first below average maximum temperature day for a week with 6.1C (-1.7C) at 13.27, currently 5.1C. Early sunshine gave way to increasing cloud before noon with first rain from next weather front falling just before 17.30.

Sunday again brought us minimal sunshine, just 16 minutes, but the air mass from mid Atlantic meant the thermometer rose to a peak of 12.7C being almost 5C above average. Likewise, the overnight minimum was well above average (+8.4C)

Several showers occurred in the past twenty-four hours amounting to 4.0mm.

Monday arrived with broken cloud and the possibility of a little more sunshine before the showers drift in on the brisk southwesterly breeze.

November 2018 review
November reversed the trend of six consecutive drier than average months with a total rainfall of 96.5mm, which was 5.2mm above the 34-year average. The extreme rainfall months of November occurred in 1990 with just 27.8mm and 203.5mm in 2002.

The wettest day occurred towards the end of the month with 16.0mm on the 27th although there were three other days when the daily rainfall ran into double figures. There were eleven totally dry days, a figure close to the average for this month.

The rainfall for the eleven months of January to November was 670mm being 83mm below the average. The extremes were 564mm in 1996 and 1043mm in 2014.

The late autumn month was slightly warmer than average, +0.7C, in contrast to September and October, which were a little below average.

We enjoyed two spells when the thermometer rose well above average due to mild, Atlantic air such as 5th to 15th, with several days at least 4C above average and the warmest day with 14.4C on the 6th. However, strong northeasterly winds brought an abrupt change from the 19th to the 26th when the opposite was true with the coldest day on the 22nd producing a maximum of only 4.5C being almost 6C below average.

An air frost was recorded on six days with the early morning of the 2nd being the coldest when the thermometer dropped to-2.0C. However, that was quite mild compared to the November 30th minimum in 2016 when the frost was severe, down to -7.3C.

Due to the passage of several Atlantic depressions, fortunately mainly to the west of southern England, we have survived a number of very windy days. The 6th to the 10th gave days with maximum gusts of 25mph and above with a peak gust of 38mph on the 9th. Storm Diana brushed close to the country at the end of the month so there were stormy days from the 27th to the 29th with the windiest day of the month occurring on the 29th with a peak gust of 47mph.

The average November sunshine total over the past four years, when that instrument was installed, stands at 39 hours but November 2018 gave us 70 hours of welcome strong sunshine.

Autumn 2018 review
Autumn, meteorologically, consists of the three complete months of September to November, purely for the ease of statistical calculations. The past autumn mean temperature was marginally above average (+0.2C).

Rainfall totalling 189mm was 49mm below the 34-year average. During the three months the equivalent rainfall of 101mm was lost through evaporation from ground sources and plant life, which was 14mm above the seven-year average, due to the drier than average September and October months.

A total of 358 hours of sunshine was recorded. That was well above the average for the past four years, which currently stands at 236 hours.

Update on Monday at 16.05. Peak temperature of 10.5C occurred at 08.00. During afternoon the wind began to veer from the southwest into the northwest with a consequent fall in temperature to currently 8.9C. Frequent heavy showers all day.