Author: Eric Gilbert

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.

During the bursts of very strong sunshine on Wednesday the thermometer rose to its highest all month with a maximum of 23.2C at 15.04 being 2.6C above my long-term average. The day was dry and the UV peaked in the ‘High’ category again. The past night was mild that saw the thermometer not drop below 12.5C at 04.46, just before sunrise in Marlborough at 04.50, being 2.3C above average.

Thursday revealed a bright start to the new day with thin high cloud. Since just before 05.00, the track of cloud on the radar showed much thicker cloud just skirting to the west of our area but just after 07.30 much thicker cloud drifted in front the southeast as a fragmented rain band edged closer.

The high pressure has moved slowly away allowing low-pressure to the west begin to dominate our weather with the rain radar showing a large area of rain edging closer from the southeast. The wind, currently from the southeast, will veer into the south later today. The barometric pressure had fallen away to 1011.5mb at 08.00, down 11mb since its peak Monday

The last four dry days have seen the loss of equivalent rainfall through evaporation from the ground and plant life exceed 3mm daily. The rainfall this month, so far, totals 25.8mm against my 41-year average of 52.9mm whilst 33.8mm of equivalent rainfall has evaporated into the atmosphere.

Puffins: the next few days will show images of Puffins taken in July 2021 on Skomer Island, Pembrokeshire.

Although there was variable cloud on Tuesday limiting the solar activity to its lowest in four days the warmer air began arriving that saw the thermometer rise to a maximum of 22.6C late in the glorious afternoon sunshine at 17.05 being 2.1C above my long-term average. This was the warmest day since 31st May. The clearer skies overnight saw the temperature drop away to a low of 8.8C at 03.42 being 1.4C below average.

Wednesday began with glorious sunshine to start the new day, however, by 06.45 cloud began to drift in from the east obscuring the sun and limiting the further rise in temperature to reach 13.2C by 08.00.

The significant change in our weather today is the arrival of an airstream from the southeast, a much warmer pool of air. This is from a direction not seen for a month. The recent high pressure has relocated a little to be over the Netherlands and reaching north over Scandinavia, that has allowed the airstream to come around its southern flank originating from the Continent.

As the day progresses, and especially on Thursday, the arrival of the warm, moist air from the south meeting the recent cooler air will likely produce storms. This coincides with a low pressure system just to the west of the UK getting much closer. The warm, moist air, being lighter than the recent cooler, heavier air, will rise rapidly over it producing unstable conditions. As the warm moist air cools with altitude it will produce precipitation, quantities and strength uncertain at the present.

Strawberry Moon: The indigenous American tribes referred to the full moon as the Strawberry Moon as it marked the harvesting of the wild strawberries. The moon will rise at 22.46 this evening with the full phase at 08.44 tomorrow.