Saturday 13th December
The westerly breeze on Friday meant a cooler air flow, with moisture, that brought occasional brief, intermittent light showers although the maximum of 10.9C was exactly the same as on Thursday being 3.4C above average. The cloud persisted throughout the day resulting in no UV light triggering the UV sensor, the fifth time this month, but we are almost at the shortest day when any light is weak.
The sky began to clear during the early afternoon, leading to a clear night that saw the thermometer drop steadily to reach freezing point (-0.1C) at 03.03 in the early hours and a low of -1.2C at 07.09 early Saturday. By 08.00 there was a slight recovery, which is unusual under a clear sky in winter when the minimum is closer to sunrise or just after, to reach -0.4C.
At first light on Saturday a narrow band of fog was observed on the higher ground above the River Og valley, unusual as radiation fog usually forms at the lowest part of the valley and where moisture is greater. By 07.30 the fog had dropped down to the valley but by 08.00 risen and began to thin. The cold start to the day and under clear skies will mean a cooler day even though we will see welcome sunshine that will result, probably in an average maximum temperature for December.
The barometric pressure reading at 08.00 was 1027.6mb and continuing to rise, evidence of the ridge of high pressure edging across the UK that will give a fine day today and into Sunday. This is from a very extensive area of high-pressure that extends from the Azores to eastern Europe. By Monday this will have moved away allowing more unsettled weather to return.