Category: Commentary

A maximum of 27.6C was logged at 17.52 on Wednesday, therefore, Marlborough has experienced a meteorological heatwave as three consecutive days with maxima above the 27C threshold have occurred, namely 27.8C, 28.6C and 27.7C respectively. The peak of 29.8C was recorded on Saturday but not consecutive with the last three days.

The past night gave us a minimum just above the 39-year average (+0.6C) with a low of 10.7C.

Thursday arrived with strong sunshine again that lifted the temperature to 18.9C at 08.00.

The high pressure system stretching from Scandinavia to the UK has intensified by 3mb since yesterday, a pressure reading of 1020.8mb at 08.00 was the highest since Wednesday. This increase combined with a slight reposition has meant the breeze has backed a few more degrees from principally north yesterday to northeast today.

Although a maximum of 28.6C was recorded on Tuesday, Marlborough has not technically experienced a heatwave. The heatwave threshold for Wiltshire is 27C and for a heatwave to be declared there must be three consecutive days when the threshold is exceeded. We have now had two consecutive days when the peak exceeded 27C, that was 27.8C on Monday and 28.6C on Tuesday but Sunday only reached 25.1C. If the maximum today is above 27C, we will be experiencing a meteorological heatwave.

The loss of equivalent rainfall through evaporation reached 5.18mm on Tuesday. So far this month the total loss to the atmosphere is 48mmm compered to the rainfall of 14.8mm.

It was a cool night as the thermometer sank to 8.6C being 1.5C below the average.

Wednesday arrived with strong sunshine again. By 08.00 the thermometer had reached 15.3C and was rising steadily.

Update at 18.00: a maximum of 27.6C was logged at 17.52 today. Therefore, Marlborough has experienced a meteorological heatwave as three consecutive days with maxima above the 27C threshold have occurred, namely 27.8C, 28.6C and 27.7C respectively.

Monday saw the temperatures began to recover after the rain of previous days. The thermometer peaked at 27.8C being 7.5C above the 39-year average.

No rain fell in the past twenty-four hours, the storms were to the north of our area. The UV level just edged into the ‘Very High’ category.

The past night was mild with a low of 11.7C, being .6C above he average.

As the land begins to dry out after the rainfall the rate of evaporation has begun to climb again. The equivalent loss of rainfall through evaporation from ground sources and plant life now totals 43mm for June against the rainfall of 14.8mm.

Tuesday saw the sun begin to shine strongly shortly after it rose above the horizon lifting the thermometer to 19.5C at 08.00. The wind has veered into the northeast again, but light.

Update at 17.30. Although a maximum of 28.6C was recorded today, Marlborough is not technically experiencing a heatwave. The heatwave threshold for Wiltshire is 27C and for a heatwave to be declared there must be three consecutive days when the threshold is exceeded. We have now had two consecutive days when the peak exceeded 27C, 27.8C on Monday and 28.6C on Tuesday but Sunday only reached 25.1C. If the maximum tomorrow is above 27C, we will be experiencing a meteorological heatwave.

Sunday was not as hot as Saturday with a peak of 25.1C, however, this was still 4.9C above the 39-year average. The wind had veered into he northwest, a direction not seen for a month and was very light with a maximum gust of just 10mph, also the lowest for a month.

A modest shower, lasting for just over half an hour, fell early evening at 19.00. The centre of the intense storm was just to the east and travelled northwestwards towards Swindon in a long line of shower cells. Thunder was heard for over half an hour in the distance. More rain fell after midnight, 01.00, and a heavier burst at 02.15 falling at the rate f 25mm/hour. The rainfall total for the day and night was 5.5mm.

Monday began with misty conditions after the rainfall but by 08.00 the sun was beginning to burst through the cloud cover and had lifted the temperature to 17.4C at 08.00 after a minimum of 15.3C at 05.11, which was 5.2C above the average. The wind today is forecast to come principally from the southeast.

The temperature steadily rose to a maximum of 29.8C at 15.02, which was 9.6C abject he average, before cloud began to arrive from the southeast and the first light drops of rain were observed. This was the hottest day since the heatwave in August 2022 when when 33.5C was noted on the 13th.

A classic Line of Convergence was seen on the radar screens at that as the hot, moist air from the Continent, brought on a southwesterly air stream, met the colder, drier air from the northeast, that had been plaguing our area for the last three weeks. The warm, moist air, being lighter, rose above the colder air mass and rapidly condensed forming storm cells that brought the first rain drops at 15.10. Further cells developed in a line to the southeast and moved northwestwards across our area, due to the wind veering from northeast to southeast, with heavy rain from 15.40. A total of nine thunder claps were heard during this period.

The showers, sometimes very heavy, produced 9.3mm of very welcome rainfall for the gardens and filled three of my 220 litre water buts. The rain eased and ceased at 17.05 and the sun began to reappear, weakly at first.

During the storm period the air temperature fell precisely 10C from 29.9C to 19.9C. The thermometer began to rise again at 17.05.

The warm air mass meant a very mild night with the thermometer not sinking below 15.7C, which was 5.7C above the average.

Sunday dawned with misty conditions and weak sunshine through variable high cloud. By 08.00 the thermometer had risen to 19.3C.