During the 7.7 hours of sunshine on Tuesday, and thanks to the light winds, maximum gust of 10mph, the thermometer rose to a maximum of 13.5C. This was the warmest day since the 4th but still 0.8C below the average.
It was another dry day, the tenth this month. The rainfall total for April currently stands at 7.4mm while the moisture lost through evaporation from ground sources and plant life is equivalent to 22mm of rainfall. The previous two months brought below average rainfall totals and with no significant rain in the forecast for severval days we are experiencing a significant dry period.
The thermometer did eventually drop below freezing overnight at 02.00 on Wednesday morning that gave a minimum of -0.3C at 03.56.
Muted sunshine on Wednesday after dawn, through thin high cloud, raised the temperature to 2.8C at 08.00. The anticyclone is still centred over the UK with light winds continuing.
The high pressure now centred over the UK has been intensifying over the past twenty-four hours, as a result it has blocked the flow of Arctic Air but left a pool of very cold, static air over the UK. The thermometer on Monday, during 6.7 hours of sunshine, rose to a maximum of 9.7C, however, this was again below average (-4.3C).
The thermometer fell steadily downwards during Monday evening and at 22.39 dropped below freezing (-0.1C), just six minutes later than the previous night. The past night has been the coldest since 11th February win a minimum of -3.9C at 06.20 on Tuesday morning being a significant 8C below average. In fact we have only had one day and night with temperatures above average.
Tuesday saw bright, if muted sunshine for the first hour but a fog bank, which had been lurking to the north of Marlborough from the Thames Valley, rolled in over the Downs so that by 07.15 the visibility had reduced to 200m. The sun disappeared half an hour later so that by 08.00 the temperature was still below freezing with a reading of -0.4C.
The anticyclone has dampened out the wind of previous days and dropped out entirely for many hours overnight thus allowing the frost to intensify. The barometric pressure at 08.00 was 1033.7mb
The welcome 6.9 hours of sunshine on Sunday, intermittent in the morning but more sustained in the afternoon, encouraged the thermometer to rise to a maximum of 9.7C, This was up 4C on the very cold Saturday peak but still 5.4C below the 37-year April average.
A brief light shower of small hail (less than 5mm in size) was observed at 13.00.
The thermometer fell steadily during the late afternoon and evening to reach freezing point (-0.1) at 22.33 on Sunday evening. It continued falling until reaching a minimum of -2.6C at 02.52 early Monday morning. At that time the advancing weather front would have started to ease in the initial cloud with humidity starting to increase after 03.10. The radar showed thick cloud and precipitation arriving over this area at 04.10, which by daylight could be seen as a covering of snow but had ceased by 05.30. In the calm conditions there was a level 1cm of snow that began to slowly melt as the thermometer had risen to 2.0C at 08.00. The equivalent liquid from the melted snow amounted to 0.8mm.
Throughout daylight hours on Saturday an area of thick cloud persisted over the area initially producing drizzle that then became light rain for almost twelve hours. It was an exceptionally cold day with the thermometer rising just a couple of degrees from that at dawn to a maximum of only 5.9C, which was a significant 8.4C below the 37-year average and the coldest since 7th March.
It was the first sunless day since 20th March with the UV peak of 1.4, which is at the lower end of “Low”.
During the early evening the temperature dropped to 2.0C and the precipitation turned to wet snow with a daily total of 6.2mm. This was the wettest day since 26th March and brought the monthly total to 6.6mm when the average is 58.5mm.
The cloud eventually thinned overnight and allowed the temperature to drop to -0.6C at 05.05 on Sunday morning that saw very brief bright intervals between occasional breaks in the cloud, which was thinner and higher than on Saturday.
We enjoyed 6 hours of sunshine on Friday with a maximum temperature of 12.5C. This was the warmest day for a week but still 1.8C below the average. In fact we have yet to have a day in April when the thermometer gets above the 37-year average maximum.
A chilly night followed as the wind late afternoon on Friday, (17.00) began to veer into the north so a colder air flow arrived. The temperature dropped away to a minimum of 3.2C being 0.9C below average.
Saturday dawned dull with a large area of thick cloud producing occasional light drizzle but not measurable thus recorded as a trace. Currently at 08.00 the wind is very light and coming from the north-northeast.