Category: Commentary

Under the influence of the high pressure system extending from mid-Atlantic to east of the Black Sea on Monday, we enjoyed yet again wall to wall sunshine that lifted the temperature to a maximum of 11.1C at 15.23, despite the very light northerly flow of air. This high was 2.7C above my long-term average and the warmest day since the 24th February when 12.3C was logged. There was a slow fall in temperature during the evening when freezing point (-0.1C) was reached later than the four previous evenings, at 21.02, and then levelled out a little to reach a minimum of -4.6C at 06.29 early Tuesday after which time the sun got to work and the thermometer engaged reverse and started to climb again.

The UV light strength rose to its highest since 8th October with a value of 2.4, still at the top end of ‘Low’, but it is only early March.

Tuesday morning was a re-run of three previous mornings with glorious sunshine, as soon as the sun rose above the horizon, that gave a temperature of -0.7C at 08.00, the highest at that time since the 27th February. As the anticyclone slowly relocates and changes in pressure the wind today will come principally from the southwest, a much warmer direction than the north yesterday, but still light in strength. However, the ground is still very cold after the succession of hard frosts so the maximum is like to climb only slightly higher than the peak reached on Monday.

The forecast synoptic charts show the anticyclone completely in charge until later on Thursday when the pressure is forecast to drop a little as the anticyclone eases eastwards. This will still provide a blocking high against weather fronts trying to make their way across the southwest, associated with a depression developing in the Atlantic, when one forecast indicates possible light rain, the other forecast another dry day.

The wall to wall sunshine on Sunday lifted the thermometer to a maximum of 10.8C at 14.46, which was aided by a very light breeze that was from a slightly warmer direction, the southeast. The sunny conditions meant the solar radiation reached a maximum of 512W/m2 and the UV to 2.3.

During the late afternoon and evening, as was expected under clear skies, the thermometer dropped steadily with a minimum of -5.2C at 06.44 early Monday, just before the sun began to halt the drop and reverse it. This low was a significant 7.0C below my long-term average and the coldest night since 11th January when the thermometer dropped to -7.2C.

The stronger sunshine and slowly lengthening days saw the UV light trigger the sensor very early at 08.34 and ceased at 16.07 after reaching a peak of 2.3, which was at the top end of ‘Low’.

Monday followed the sunny start to the previous two days although by 08.00 the thermometer had only risen to -2.2C.

Although we have now had considerable sunshine for the past three days the nights have been getting steadily colder, which is slowly seeping deeper into the ground. The soil temperature at a depth of 5cm, read daily at 08.00, has been logged at 3.3C, 1.2C, 0.9C, 0.6C and 0.4C respectively, for the last five days. I have also noted the time when during the evenings the air temperature has dropped to freezing, taken as -0.1C, and it is getting earlier every evening over the past four days. The times were 22.30, 21.25, 20.51 and last night at 20.27. The official forecasts recently have indicated minima around 2C but Marlborough has always been colder than the area forecast. I have often noted on a winter’s night, as I approach the town from the north and east, that the car’s thermometer indicates the outside temperature has dropped a degree as I get closer to the town.

I should add that the new professional weather station records data every five seconds, which I can access for every minute of the day.

The high pressure system extends from mid-atlantic as far east as the Black Sea and will be in charge of our weather for the next few days.

Saturday was another day when the northeasterly air flow limited the rise in temperature with a flow of cool air that resulted in a maximum of 9.7C at 14.27 being 1.0C below the early March average. It was almost wall to wall sunshine although the very thin, high could meant the peak solar radiation was the lowest for three days. During the evening the thermometer slowly fell away to reach freezing point (-0.1C) at 20.51, hovered around -1.2C for a couple of hours then continued to drop reaching a minimum of -4.6C at 07.02 on Sunday being a significant 6.5C below my long-term average.

The UV level peaked at 2.3, the highest since 18th October 2024 and at the top end of ‘Low’. Not surprisingly, the equivalent loss of rainfall through evaporation from ground sources and plant life increased again to 1.47mm

Sunday after dawn revealed another clear sky and sunshine as soon as it rose above the horizon, so another fine day ahead. The significant change is in the direction of the wind that has veered into the southeast, a sightly warmer direction, signalling a small but significant change in our weather ahead as the daytime temperatures will begin to ease upwards. The breeze will continue very light under the dome of high pressure that at 08.00 registered 1035.5mb, the highest pressure since 6th February.

The anticyclone is still centred over the UK. The forecast synoptic charts indicate that the high pressure will dominate our weather well into the new week with much fine weather ahead and the temperature easing upwards with still light winds.

Although we are enjoying many hours of sunshine the colder nights have seen the temperature of the soil at a depth of 5cm slowly drop away, not good news for early gardeners, with a temperature of 0.6C at 08.00.

February 2025 Review

The month began with three mild days that produced above average maxima with the wind from the south, peaking at 10.7C on the 3rd, which was 2.4C above the average.

It all changed when a large area of high pressure developed over the country extending east across to the far Continent. The barometric pressure on the 6th was logged at 1044.7mb, an unusually high pressure. That was the highest pressure since 5th February 2023. The anticyclonic dome brought cold, moist air on a persistent northeasterly that depressed temperatures by day, the maximum of just 3.1C on the 10th was the coldest day 10th January. These were depressing days.

Nighttime minima were mostly above average due to the continuous thick cloud that acted as a duvet restricting the loss of any warmth into the atmosphere.

On the 9th a very large area of low pressure in the eastern Atlantic pushed a very wide rain band across the country, the most significant precipitation for a week, with a fall of 16.2mm recorded.

The diurnal range of temperature, the difference between night and day extremes, was unusually small on the 10th with 3.1C by day dropping to just 2.3C overnight, thus a difference of just 0.8C.

The high pressure persisted throughout the second week with very cool, moist air on a modest northeasterly breeze. There was no sunshine to produce any warmth by day, just gloomy weather, although the wind was light with minimal wind chill.

The first indication of a change from the cold, gloomy days was sunshine on the 17th that saw the UV light sufficient to trigger the UV sensor continuously between 10.00 and 16.00 with the greatest strength since 31st October, with a reading of 1.3, even so it was still in the ‘Low’ category.

After a ten day battle the high pressure gave way to the depression on the 19th that brought a significant change in our weather. The cold, gloomy days with calm conditions gave way to more unsettled conditions with welcome higher temperatures but periods of rain. The barometric pressure dropped to its lowest all month with a low of 1004.4mb on the 21st.

The stream of warm air from around the Azores region saw maximum temperatures rise again to double digit maxima with 13.4C logged on the 21st being 4.1C above my long-term average.

The wettest day of the month occurred on the 23rd when several hours of continuous rain, heavy at times, produced a daily total of 18.0mm. In the first of two short but sharp showers on the 24th small hail (classified as less than 5mm in diameter) were observed that in the space of ten minutes saw the temperature drop over 3C.

An anticyclone developed in the eastern Atlantic throwing a ridge across the country on the 27th producing a significant change in our local weather with fine dry days although nighttime air frosts occurred under clear skies as it’s centre settled over the country, just to the north of Marlborough.
The high pressure built on the 28th that saw the highest UV all month with a reading of 2.1, which was at the top end of ‘Low’, also the highest since 18th October 2024. Because of the many hours of sunshine and the light breeze that was less humid, the equivalent loss of rainfall due to evaporation from ground sources and plant life was 1.35mm.

The total rainfall for the month was 76.2mm being 112% of the 40-year average or plus 8.2mm. There were three days when fog was observed in the morning and one day when small hail was observed.

The breeze from the northeast on Friday limited the rise in temperature again with a maximum of 9.6C at 13.13, however it was 1.3C above the long-term average. The highest value of UV light was recorded with a reading of 2.1, being at the top end of ‘Low’. The equivalent loss of rainfall of 1.35mm, due to evaporation from ground sources and plant life, was the highest since 5th October. This was a result of the many hours of warm sunshine and lower air humidity on a light northeasterly breeze, following the considerable rainfall on previous days.

Saturday revealed that the barometric pressure had risen again with a reading of 1034.2mb as the anticyclone intensified. The downside was a hard air frost with the minimum of -4.1C recorded at 07.00 before the sun got to work.

February 2025 Review

The month began with three mild days that produced above average maxima with the wind from the south, peaking at 10.7C on the 3rd, which was 2.4C above the average.

It all changed when a large area of high pressure developed over the country extending east across to the far Continent. The barometric pressure on the 6th was logged at 1044.7mb, an unusually high pressure. That was the highest pressure since 5th February 2023. The anticyclonic dome brought cold, moist air on a persistent northeasterly that depressed temperatures by day, the maximum of just 3.1C on the 10th was the coldest day 10th January. These were depressing days.

Nighttime minima were mostly above average due to the continuous thick cloud that acted as a duvet restricting the loss of any warmth into the atmosphere.

On the 9th a very large area of low pressure in the eastern Atlantic pushed a very wide rain band across the country, the most significant precipitation for a week, with a fall of 16.2mm recorded.

The diurnal range of temperature, the difference between night and day extremes, was unusually small on the 10th with 3.1C by day dropping to just 2.3C overnight, thus a difference of just 0.8C.

The high pressure persisted throughout the second week with very cool, moist air on a modest northeasterly breeze. There was no sunshine to produce any warmth by day, just gloomy weather, although the wind was light with minimal wind chill.

The first indication of a change from the cold, gloomy days was sunshine on the 17th that saw the UV light sufficient to trigger the UV sensor continuously between 10.00 and 16.00 with the greatest strength since 31st October, with a reading of 1.3, even so it was still in the ‘Low’ category.

After a ten day battle the high pressure gave way to the depression on the 19th that brought a significant change in our weather. The cold, gloomy days with calm conditions gave way to more unsettled conditions with welcome higher temperatures but periods of rain. The barometric pressure dropped to its lowest all month with a low of 1004.4mb on the 21st.

The stream of warm air from around the Azores region saw maximum temperatures rise again to double digit maxima with 13.4C logged on the 21st being 4.1C above my long-term average.

The wettest day of the month occurred on the 23rd when several hours of continuous rain, heavy at times, produced a daily total of 18.0mm. In the first of two short but sharp showers on the 24th small hail (classified as less than 5mm in diameter) were observed that in the space of ten minutes saw the temperature drop over 3C.

An anticyclone developed in the eastern Atlantic throwing a ridge across the country on the 27th producing a significant change in our local weather with fine dry days although nighttime air frosts occurred under clear skies as it’s centre settled over the country, just to the north of Marlborough.
The high pressure built on the 28th that saw the highest UV all month with a reading of 2.1, which was at the top end of ‘Low’, also the highest since 18th October 2024. Because of the many hours of sunshine and the light breeze that was less humid, the equivalent loss of rainfall due to evaporation from ground sources and plant life was 1.35mm.

The total rainfall for the month was 76.2mm being 112% of the 40-year average or plus 8.2mm. There were three days when fog was observed in the morning and one day when small hail was observed.

Once again, although, we had many hours of sunshine on Thursday we were still under the flow of cool air brought on a northwesterly and later a northerly airstream from the north Atlantic, not Arctic, so it moderated the rise in temperature. The maximum of 9.8C was logged at 14.39 being 1.4C above my long-term average. The clear skies saw the thermometer fall slowly late afternoon and early evening registering freezing point (-0.1C) at 22.29 where it hovered until after 01.30 when it fell further with a low of -2.7C at 07.40 early Friday, which was 4.5C below the average.

There were two significant meteorological events on Thursday registered on my station. The UV light was the strongest since 25th October with a value of 1.8 at its peak being at the top end of ‘Low’. The equivalent loss of rainfall through evaporation from ground sources and plant life totalled 1.32mm being the highest since 5th October as the ground had been very wet following the recent substantial falls of precipitation.

Friday revealed a sunny start to the day, even if the sun’s strength was weak initially. There were misty conditions at first with fog observed rolling in from the north after 07.40 but then receded and dispersed by 08.15. The thermometer climbed back above freezing at 08.18. The air stream has veered into the northeast today although the conditions last night and this morning are calm with the anemometer stationary.

The anticyclone has built considerably over the past twenty-four hours and is centred just to the north of Marlborough with the pressure reading at 08.00 of 1030.2mb, a rise of 10mb since Thursday at that time. This is going to give us a few fine, dry and sunny days although air frosts are likely to occur during the next two nights.

The synoptic charts indicate that this high pressure system will be dominate our weather for the next few days with much sunshine although not high temperatures as the air stream until Monday will come predominantly from a northerly quadrant, when it is then forecast to back into a westerly quadrant, which will see the daily temperatures begin to rise with the end of night frosts.