Category: Commentary

The significant feature regarding Monday’s weather was the exceptionally high UV level, which during the bursts of strong sunshine was in the Very High category for two hours between 12.37 and 14.28, either side of midday, not surprisingly. However, the peak of 8.1 was at the very top end of the Very High category and the highest since 4th August 2024. The strong sunshine and light winds from the west, a maximum gust of just 10mph was recorded, saw the thermometer soar to a maximum of 24.1C at 16.49 being 3.5C above my long-term average. The intense solar activity produced a peak radiation of 1188 W/m2 at 12.53. The overnight minimum was 10.6C, just 0.4C above average, which was logged at 05.15 early Tuesday.

The start of Tuesday brought us bursts of sunshine, between variable cloud, that had lifted the temperature to 16.3C by 08.00. Today will see the cloud cover varying as a weak weather front passes southwards across our area.

The anticyclone now extends from the eastern Atlantic across to Germany with its centre just off the coast of Brittany. As we are now close to the centre of the high pressure the winds will continue light and from the west.

Later on Wednesday and into Thursday the high pressure will relocate a little to the east and elongate northwards that will then bring an air stream around its southern flank, originating from southern France and Iberia, which will mean the temperatures will increase over the next few days.

Puffins are about 20cm tall and breed in large colonies, such as the one on Skomer Island, Pembrokeshire. They breed in large colours on coastal cliffs or offshore islands.

The breeze from the west and variable sunshine on Sunday, especially in the morning, limited the rise in temperature to a maximum of 22.1C at 14.13, which was 1.5C above average and almost identical to the high on Saturday. The anticyclone has moved much closer to the UK with the pressure rising 8mb since Saturday. The low of 13.0C was logged just before midnight at 23.59 when the minimum is usually much later, towards dawn. This low was 3.7C above average.

Monday began with variable sunshine and bursts of sunshine that saw the thermometer climb to 17.2C by 08.00.

The high pressure has now extended over the UK and towards the Continent and is likely to dominate our weather for the rest of the this week that will see temperatures climbing over the next few days. The barometric pressure at 08.00 read 1029.2mb, which was the highest since the end of December. The slight relocation of the high will see the breeze continue to come from the west today. The centre of the anticyclone is in the western approaches to the English Chanel so being almost under the centre of the high the wind will be light today.

The warmer days and nights have seen the heat slowly penetrate further into the ground. The temperature at a depth of 5cm has risen steadily with 15.3C, 17.2C, 17.9C, 18.4C, 17.3C and then 19.2C today over the past six days and will continue to rise as the week progresses. The temperature of 19.2C at 08.00 made it the highest since the 12th August 2024.

Once again the numerous showers, some very active with heavy rain shown on the rain radar, passed on a northeasterly trajectory to the northwest of Marlborough. There was a particularly heavy shower that glided past, just five miles north, at 15.30. However, there was a very brief, light shower at 19.50 that produced just 0.9mm. The sunshine between the variable cloud was very strong with the solar activity peaking at the top end of the ‘High’ category with the highest solar activity for a week with a peak burst of 1030 W/m2. The past night saw the thermometer not drop below 10.8C, logged at 04.40, as the sun rose over Marlborough at 04.50.

Sunday revealed a very sunny start to the new day with the temperature reaching 15.8C by 08.00.

The anticyclone has edged much closer as the depression departed, that has seen the barometric pressure rise to 1022.2mb at 08.00, the highest pressure this month. The forecast charts indicate that this anticyclone will continue to build and extend its influence so that the coming week will bring more very warm, dry and sunny weather with no indication of rain at the moment for the next few days.

During the winter I often mention wind chill when it is cold and windy that makes it feel colder outside on the skin than that indicated on a thermometer, referred to as the THW Index using temperature, humidity and wind strength data. During very warm and hot days, as recently, there is a different index, referred to as the THSW Index, that additionally uses solar activity to suggest what it might feel like outside on the skin when the sun shines strongly. An example was on Saturday at 15.30 when the sun shone strongly resulting in an air temperature of 22.2C when the THSW Index indicated it felt more like 28.2C outside.

Puffins have beautiful markings, a strikingly coloured bill and a comic gait that are sometimes referred to as ‘sea parrots’ but in Northumberland as a ‘tommy noddy’.

The southerly air stream and intense sunshine on Friday pushed the temperature steadily upwards to reach a peak of 26.2C late in the afternoon at 16.18. This high was a significant 5.6C above my long-term average making it the warmest day this month also since 12th August 2024. Once again major rain bearing areas travelled up the west and east of central England, so no rainfall. The UV level was at the top end of ‘High’.

Often in the winter we get a wind chill factor making it feel colder outside than indicated on a thermometer, the THW Index. Yesterday was the opposite when not only temperature, wind strength and humidity was taken into account but also the strong sunshine, the THSW Index. At the peak temperature of 26.2C it felt more like 32.0C outside on the skin.

Due to the very warm day and warm air stream also a cloudy night the thermometer did not drop below 16.2C, logged at 02.25, which made it the warmest night since 3rd September 2024.

The new day on Saturday dawned dull and misty with low cloud draping the Marlborough Downs and Savernake Forest. These conditions were as a result of a band of thick cloud drifting northwards that at 07.00 produced a little drizzle. The wind will continue to come from a mainly southwesterly direction.

Today we are under a complex area of low pressure that is producing another weather front that will cross the UK today. By tomorrow this weather system will begin to drift into the North Sea as an area of high pressure edges in from the west. The outlook into next week is for a return of very warm and dry weather as the anticyclone establishes itself over and around the UK.

Skomer Island: Skomer Island together with Skokholm Island form the largest breeding Puffin colony in Southern Britain.

The forecast disturbances with torrential rain did occur on Thursday, however, the heavy and continuous rain sidled northwestwards just to the west of our area. There was almost continuous light rain from just before midday until around 13.30 that amounted to 4.8mm that took the monthly total to 30.6mm when my 41-year average for June is 52.9mm. Due to the cloud and rain the maximum temperature was restricted to a peak of 21.8C late in the strong afternoon sunshine at 17.57, being 1.2C above average.

The past night was exceptionally mild thanks to the flow of warm area originating from Iberia. The minimum of 14.4C at 03.54 was 4.2C above my long-term average, which made it the warmest night since 23rd September 2024.

The Heat-health Alert Service has given a warning that just reaches into our area today as a result of the high temperatures and high humidity, that can especially affect older persons.

The new day on Friday began with variable cloud allowing bursts of strong sunshine that had lifted the temperature to 17.3C by 08.00. The weather systems over the UK are a bit messy with various areas of low pressure close to a high pressure further east over the Continent reaching into Scandinavia. The depression today will slowly move up the east cost of the UK into the North Sea, which will result in the wind veering from a principally southwesterly for much of the day to come from the east and possibly northeast to night.

Skomer Island: Skomer os an internationally important seabird island with over 41,500 Puffins, less than a mile off the beautiful Pembrokeshire coast.