Category: Commentary

The thunderstorms did breakout as forecast but not over Marlborough. The rain radar showed a vigorous line of storms developing and spreading northwest from London, near Oxford and to the Midlands then Wales. As a result we had many hours of strong sunshine that lifted the temperature to a peak of 21.1C late in the afternoon at 17.28. This peak was 3.8C above my long-term average but less warm than on the previous two days. Initially overnight the sky remained mostly clear so the thermometer began to fall steadily but just after 01.00 thin cloud began to drift across from the depression that slowed the decline reaching a minimum of 6.3C at 05.47 just after sunrise at 05.19 in Marlborough. The UV level rose to a high level for the second consecutive day.

Tuesday revealed a cloudy start the day after a little brightness before 06.30 as more cloud from the low pressure system over the Bay of Biscay continued to feed on a light easterly breeze.

The depression is very slowly easing westwards into the Atlantic and gradually beginning to fill whilst the high premise to the north has been building down over the country with a rise of 7mb since yesterday with a reading of 1017.6mb at 08.00.

Whilst gardeners and farmers bemoan the lack of rain since the end of February, the rate of evaporation from ground sources and plant life, surprisingly, continues at quite a high rate. Six days this month has seen in excess of 4mm of equivalent rainfall lost on each day. Whilst we had 0.6mm of precipitation on Sunday the total loss for May, from evaporation, now exceeds 40mm.

The high pressure centred to the north of the UK will build a little higher whilst at the same time it will slowly extend its influence further south over the UK that will, from Wednesday, produce more fine, sunny and dry days with little sign of precipitation of any significance until after the weekend and, possibly well into the following week.

This will be the last image of tulips from Malmesbury Abbey Gardens that I took in 2006. The following days will contain images from the Swannery at Abbotsbury near Weymouth, a home of over 600 mute swans.

After a sunny morning on Sunday the cloud built gradually after around 13.00 and then thickened before 15.00 that produced a few drops of rain at 15.15, also observed again just before 15.45, but not enough to wet the ground, I could count the number of drops per square metre there was so little when the gardens and fields are desperate for steady rainfall over a few hours. However, there was a light shower that started just before 06.00 early Monday that produced just 0.6mm of precipitation. The brief heavy showers were, once again, to the north of Marlborough, around Swindon, and west of Marlborough, Melksham would have had a heavy shower.

The maximum temperature on Sunday was 24.3C being exactly 7C above my long-term average being the warmest day since the 1st when 28.1C was logged. The peak was logged at 13.07 before the cloud began to increase. The past night, thanks to the variable cloud cover, was very mild with the thermometer not dropping below 11.9C, logged at 05.16 early Monday, which was 4.9C above average and made it the warmest night this month also since the 6th December.

The start to Monday revealed total cloud over with the odd minor break when the sun broke through. This is thanks to the depression still over the Bay of Biscay throwing a large sheet of cloud across southern England as the air stream rotates anticlockwise from a southeasterly wind direction, however, for the next two days much lighter in strength.

Finishing this report at 08.30 the sun has broken through to lift the temperature to 15.1C, however, the rain radar shows a band of heavy showers crossing the Channel and just reaching the south coast, from Swanage in the west to Hastings in the east, with a few further behind in mid-Channel, that might just bring some rain later this morning. The rain at the moment is particularly heavy from Southampton to Portsmouth.

Looking forward, Tuesday will probably bring much lighter cloud cover, with hopefully some sunshine, as a high pressure will exert itself from the north pushing the depression back into the Atlantic from whence it came. There could be the occasional shower from the rising temperature as fair-weather clouds could bubble up producing cumulus clouds that might produce a heavy shower.

The rest of the week looks to return to dry, sunny and warm conditions as the anticyclone close in and buck,kds producing a block g high agar st and weather fronts approaching from the Atlantic.

The modest change in wind direction on Saturday, coming from the east and east-southeast, meant the air stream had travelled from the Continent rather than over the cool, damp North Sea. As a result the thermometer rose to a maximum of 22.1C at 16.5 being 4.8C above average making it the warmest day since the 2nd. Not only was the air warmer but dryer as the humidity dropped to a low of 29.7% at 16.10, with of course the UK land also being very dry. The overnight minimum of 7.4C, logged at 05.21, at the sunrise time of 05.22 for Marlborough, was the first above average low since the 3rd being plus 0.4C.

The start to Sunday revealed welcome sunshine that was at times a little muted as advance cloud from the depression over the Bay of Biscay is beginning to influence our weather. The centre of the low pressure system is over the Brest peninsula and at 07.30 was already producing numerous thunderstorms over The Isles of Scilly and the Cherbourg peninsula. The big question is how far will the thicker cloud and any possible thunderstorms migrate northwards. Rain has been falling over Cornwall for the past few hours and was edging into west Devon at 08.00. The barometric pressure has fallen another 8mb since yesterday as the depression moved a little closer.

The track of this depression is likely to be centred over the Bay of Biscay today and tomorrow before it is forecast to decay and slip back into the Atlantic as high pressure is likely to build back over the UK from the north, possibly on Tuesday. Monday is likely to come under the influence of the depression with more cloud and possible precipitation, but amounts uncertain at this time.

There was a great improvement in the warmth on Friday as the thermometer reached a maximum of 18.9C late in the afternoon at 16.40 being 1.6C above my long-term average it was also the warmest day since the 2nd (23.7C). The significant change was in the direction of the wind that during the afternoon veered a few degrees from the cool northeast, after crossing the cold North Sea, to come from the southeast, which cut off the flow of cool air with that from the Continent having travelled over land being comparatively warmer. Although the past night saw another below average minimum of 5.4C (-1.6C) at 05.30, it was the equal coolest since the 3rd May.

Saturday saw welcome sunshine from the beginning of the new day in clear blue skies. The anticyclone continues to edge away, a drop of another 2mb since yesterday, but still playing a major influence in our weather with another dry and very sunny day ahead. The drier air from the Continent gave a humidity reading of 73% at 08.00, the lowest humidity reading since the 4th, whilst the thermometer had risen to 12.6C by that time making it the warmest start to a new day since the 2nd.

The low pressure system that I mentioned yesterday, positioned over Iberia and the Bay of Biscay, is likely to slowly edge our way over the next day or two with the likely position over the English Channel tomorrow. As a result, being so close to the UK, it could begin to throw cloud and possible rain over southern England on Monday.

I mentioned the lack of recent rain yesterday. Since the 1st April there have only been five days with any precipitation, four of those being of minimal quantity. This year is the driest March to April period I have recorded since the station was started in 1984 with just 17.4mm. Looking back over the records I found that the year 2011 was the previous driest March and April spell with only 18.1mm, however, by comparison in 2023 I recorded 239mm of precipitation.

Looking at the data on the Thames Water website I see that the ground water state from several boreholes is normal for our area although five out of the seven report the level is falling.

I noted yesterday that several water companies are begin to make plans in case the very dry spell continues into the summer.

Thursday turned out to be the coolest day for three days under variable cloud, limited sunshine and a brisk northeasterly wind. The maximum of 14.4C at 16.24 was 2.9C below average. The minimum overnight was also below average with a low of 2.7C logged at 05.41 just after sunrise having coincided with the cloud arriving. This low was a significant 4.3C below average.

Cloud began to drift across from the North Sea on the northeasterly breeze just before 06.00 on Friday that initially blocked out any sunshine but shortly after 07.30 the cloud thinned and began to break allowing the sun to break through and lift the temperature to 7.7C by 08.00. There is the prospect of a warmer day today with the wind backing into the east cutting off the flow of very cool air from the North Sea.

The disturbance over Iberia, that is developing into a low pressure system, is likely to slowly move northwards tomorrow into the Bay of Biscay and get very close to the UK on Sunday with likely more cloud. However, by Monday, as the recent high pressure eventually relinquishes control the low-pressure system is likely to elbow itself across the Channel to southern England with the prospect of showers, its movement north and east is not certain at this time.

The Government’s national drought group convened with a minister this week as England recorded its driest March to April period since 1956. Drought in the UK is characterised by a prolonged period of unusually low rainfall, leading to water shortages. Specifically, a drought is defined as a period of at least 15 consecutive day with less than 0.2nn of rainfall. We have just had sixteen consecutive dry days with no precipitation.

The rainfall during the March and April period for England was 43% and 56% respectively. Marlborough had far, far less with 9% and 20% respectively. I read that the ground water levels are good at this time.