Category: Commentary

During the course of Saturday three minor, but distinct weather fronts crossed our area that brought cloudy conditions by 09.45 and continued into the early afternoon. Precipitation amounts were minimal, twice there were just spots of rain, at 11.05 and 12.55, with a very brief shower at 13.40 amounting to just 0.3mm. The thermometer then began to rise as the clouds thinned and cleared reaching a peak of 29.7C late in the afternoon at 17.52 being a significant 9.1C above my long-term average. It has been another mild night with a minimum of 14.6C logged at 05.24 after the sunrise in Marlborough at 04.50. The low was 4.4C above average.

Sunday brought blue sky to greet the new day that enabled the sun to lift the temperature to 19.4C by 08.00 although as the day progresses cloud is expected to bubble up so the prospect of a day with sunny intervals ahead.

We have now experienced twelve consecutive days with maxima above average, many significantly above, likewise we have had eleven consecutive nights with minima well above average.

The significant change in our weather pattern is now underway. Gone are the very hot and dry days as the recent, dominant high-pressure eases away to the east over Greece and Turkey whilst allowing the depression to the northwest, near Iceland, to begin influencing our weather. This change has seen the wind veer from the recent southeasterly direction to come from a south-westerly quadrant bring in an Atlantic air stream, cooler and more moist. Whilst the battle continues the wind will increase today due to the increased pressure gradient between the two weather systems. The barometric pressure has dropped 14mb since its high last Monday with a reading of 1015.2mb at 08.00 on Sunday.

The projected Jet Steam track is for it to stream across the UK rather than to the north. Last week it had allowed hot air to arrive from the Continent, the change will see the arrival of cooler and more moist air with temperatures closer to normal.

Puffins: Puffins nest in burrows, typically dug into grassy slopes on cliffs or near the coast, the image is an example. These burrows, often about three feet deep, are lined with grass, feathers and other soft materials.

Between breaks the strong sunshine was relentless on Friday, that saw the thermometer soar to a maximum of 29.1C at 16.16, however this peak was 1.6C down on the Thursday high but still a significant 8.5C above my long-term average. There was a dip in sunshine between 12.15 and 14.00, due to light cloud drifting across, that limited the eventual peak in temperature. It was the sixth consecutive dry day with the UV level peaking at the top end of ‘High’. The Amber Heat Health alert issued by the Met Office was fully justified.

The past night has been very warm with the thermometer not sinking below 16.2C at 03.41 early Saturday, being exactly 6C above average.

The start to Saturday saw a magnificent sunrise, however, a few large spots of rain were observed falling at 05.20 that were very brief and did not completely cover a hard surface and then promptly dried up, thus recorded as a ‘trace’. The rain radar at that time showed a very small, isolated shower right over Marlborough, matching the small shower simultaneously over Swindon. The shower came from an area of cloud that then limited further sunshine until after around 08.30. Today will bring sunny intervals as the weather pattern is changing with three weather fronts forecast to cross our area after midday. The rain radar at 08.30 indicated bands of heavy shower activity moving across Cornwall and Devon, which might eventually arrive here later today.

The high pressure system that brought the recent hot, sunny weather is slowly edging eastwards whilst a depression just south of Iceland is edging closer. This significant change in weather over the UK will see the wind, much later today, veer from the recent southeasterly to southwest heralding the breakdown in the hot, sunny weather. This change will mean we are then under the influence of Atlantic weather systems with temperatures returning closer to the normal for late June.

The hot dry weather recently has seen the river levels fall a couple of centimetres, however, the River Kennet at Winterbourne Monkton, near its source, dried up a few days ago.

Puffins: I mentioned yesterday the brightly coloured beaks of Puffins in the mating season. They shed the colourful outer parts of their bills after the breeding season, leaving a smaller and duller beak.

The relentless heat continued to build on Thursday reaching a maximum of 30.7C late in the afternoon at 16.51 being a significant 10.1C above my long-term average. It was also the hottest day since 19th July 2024 when the exact maximum was recorded. Not only was it hot but the air was very dry with the humidity very low with an exceptional minimum of 38% logged at 17.54.

A thin veil of cloud was observed drifting across from the west around 17.00 that meant the sun became more variable and weaker in strength. This cloud cover thickened just after midnight when looking back at the cloud radar. This meant that the past night was less cool with a minimum of 14.4C at 05.20, being 4.2C above average, as the cloud minimised the loss of warmth into the atmosphere, compared to previous nights.

The start to the new day on Friday revealed muted sunshine as the cloud limited the strength of the sun. The thermometer had risen to 19.3C by 08.00 and stabilised there for quite a time. There was also a light breeze from an easterly quadrant that meant it felt less oppressive first thing.

In contrast to the heat and strong sunshine this week, the Met Office yesterday sent out an email inviting the public to submit their suggestions for storm names for the upcoming 2025-26 season. They stated “The naming initiative helps the media and the public communicate about the impact of severe weather events more effectively.” Now in its eleventh year, the Met Office works with Met Eireann in Ireland and KNMI n the Netherlands to compile the list.

They continue “We name storms because it works. For Storm Eowyn in January, the UK’s most powerful windstorm for over a decade, past-event surveys suggest that 99% of people within the red warning area were aware of the warnings, and 89% of them took action.”

Saturday will be the last of the very hot days as the anticyclone edges away and we begin to come under the influence of a depression edging in from the Atlantic that will bring cooler, more moist air on a breeze from a southwesterly quadrant. This will see temperatures drop several degrees but likely to be just above average.

Puffins are known for their large, triangular-shaped beaks, which are brightly coloured during the breeding season.

The thermometer on Wednesday slowly climbed during the day to reach a peak of 28.5C at 17.21 being a significant 7.9C above my long-term average that made it the hottest day since 12th August 2024 (29.3C) with more heat to come over the next two days. Thankfully, to make sleeping more comfortable, the air temperature does drop away significantly overnight with a minimum of 11.0C at 05.18 early Thursday, which was just 0.8C above the average for June.

The new day on Thursday brought strong sunshine after sunrise that had lifted the temperature to 20.9C by 08.00. The slight relocation of the high pressure will see a drift of air from a southeasterly quarter dragging up hot air from the Continent today.

The persistent heat has slowly driven further and further into the ground that combined with warm nights has sent the ground temperature at a depth of 5cm to continue to rise with a reading of 22.3C at 08.00 this morning.

The anticyclone continues to very slowly edge eastwards with its centre now over the Netherlands, as a result the air circulating clockwise around its southern flank will feed the hot air from France and Iberia over the UK until Sunday, then there will be a significant change with more of an Atlantic influence and more modest maxima.

The high temperatures, not surprisingly, have resulted in the equivalent loss of rainfall due to evaporation from the ground and plant life rise significantly. The last two days has seen in excess of 5mm evaporate each day. The rainfall for June to date is just 31.5mm whilst the loss of equivalent rainfall now stands at 64.5mm.

The heatwave threshold for the Marlborough area is 27C. The maximum yesterday was above that figure, which will happen again today and also tomorrow. Thus we are technically experiencing a heatwave, which is described as three consecutive days with temperatures rising above the heatwave threshold. The original heatwave thresholds were based on the reference climate period of 1981-2010 and were intended to be flexible and revised in the light of climate change, therefore the heatwave thresholds were revised in 2022, using the most recent 1991-2020 climate averaging period, with the local threshold temperature rising from 26C to 27C. The review saw six counties move from 27C to 28C, one from 26C to 27C and one from 25C to 26C, the areas changed were in the south of the UK and the Midlands.

The image is of a puffling, a puffin chick.

The maximum of 24.3C on Tuesday was 3.7C above average making it the warmest day since 1st September. The UV level was again, not surprisingly, Very High with a value of 7.1. The overnight minimum under clear skies was 12.4C logged at 05.18 early Wednesday just after sunrise in Marlborough at 04.49.

There was glorious sunshine to start the new day on Wednesday with the light breeze coming from a northwesterly direction. The centre of the anticyclone is just off the northwest coast of Wales so light winds under the high pressure sitting over the UK due to little pressure gradient.

The high pressure will be the dominant feature well into next week. However, tomorrow it will ease a little further eastwards and northwards allowing the air stream to run around its southern flank bringing the extra heat from a hot Continent when the wind will veer into the southeast or south southeast. The heat will be maintained up to the weekend and into next week but by Sunday it will drop a couple of degrees from the peak temperatures.

Around 90% of the Atlantic puffin population are found in Europe with 80% in Iceland and Norway, the remaining 10% breed around Britain and Ireland.