Category: Commentary

The flow of moist, but warm Atlantic air continued on Monday but with no sunshine meant a cooler day although the maximum of 11.3C was still 3.3C above the average. There was no rain and without sunshine no wonder the UV level was low with a value of just 1.2.

Tuesday at first light revealed that fog had formed overnight limiting visibly initially to 300m, but this eased by 08.00 to 500m.

The anticyclone that has influenced our weather for over two weeks has all but disappeared so this is likely to be the last dull, warm and moist day with the air movement continuing from the southwest. Change is around the corner from Wednesday.

The glorious sunshine on Sunday meant a warm day and thus produced the greatest equivalent of daily rainfall loss, 1.01mm, through evaporation from ground sources and plant life, since 26th October. The evaporation this month equals an equivalent loss of 10mm of rainfall when the actual rainfall total is just 2.5mm.

The sunshine felt quite warm and boosted the temperature to 12.5C, which was 4.5C above the average. During the evening the thermometer dropped to 5.3C at 20.25 before advancing cloud stopped the fall and produced a rise of a degree that by 08.00 on Monday read 7.1C.

At first light on Monday it was obvious that the warm and moist air had returned with low, thick cloud masking the Marlborough Downs and Savernake Forest. As the centre of the anticyclone is still relatively close, over Brittany, the barometric pressure is still quite high with a reading of 1026.0mb at 08.00. The position of the high pressure will mean the air movement will back a few degrees and come from the southwest today, still feeding in the mild, moist airstream.

Saturday brought little sunshine with the cool westerly breeze gusting to 27mph, the strongest gust for a month. The maximum of 11.7C brought the coolest day for a week but still 3.7C above the average. Once again there was no overnight frost with the thermometer not sinking below 5.6C at 05.54, which was 4.0C above the average.

Sunday dawned a little brighter thanks to temporary ridge of high pressure that meant the cloud was more broken, higher and thinner. The barometric pressure had risen to 1028.4mb at 08.00, the highest since the 12th.

The moist, warm air brought, on a southwesterly breeze on Friday, meant another mild day and night with maximum and minimum of 12.0C and 9.2C being +4.0C and +7.6C respectively. Storm Otto, that was centred off the north of Scotland, meant it was the breeziest day for over a month with a maximum gust of 26mph (14th January 41mph).

Bands of light drizzle occurred occasionally that only amounted to 1.3m but it was the wettest day since 15th January (4.0mm).

Saturday began gloomy as did Friday and Thursday with total cloud cover, thick and a low cloud base. The high pressure centre has slipped southwards into the Atlantic which means the wind will veer a few degrees to come from the west today. The ground temperature at a depth of 5cm registered 8.9C at 08.00, the warmest it has been since 12th January (9.3C).

Temperatures by day and night were well above average with a maximum of 12.8C (+4.8C) and a minimum of 9.4C (+7.8C) due to the run of warm, moist air from the Atlantic brought on winds from the southwest and south later in the day.

Friday arrived as Thursday with total cloud cover with the wind having picked up in strength with a maximum gust of 24mph. The distinct change in the wind, after many days of calm or minimal air movement under the intense high pressure was due to the anticyclone easing away eastwards and the arrival of Storm Otto. This storm was named by the Danish Meteorological Institute as it was forecast to have more impact on their country but Scotland and northern England have experienced gale force winds.

The temperature at 08.00 was 10.3C making it the warmest start to a day at that time since 15th November (11.6C).