Month: September 2024

Under the high pressure on Saturday the sun lifted the temperature to 18.8C by 15.36, the highest for a week but just below my 40-year average at -0.3C. Although the breeze from the southwest had picked compared to the previous day it felt so much warmer. The minimum of 5.2C at 06.43 early Sunday, exactly sunrise time for Marlborough, it was the least cool for four days but still 3.5C below my long-term average. It ws a dry day with the UV level at 4.8, the highest fr four days, being at the top end of ‘Moderate’.

Sunday began with the sunshine weakly after sunrise thought thin c;oid pn the eastern horizon bit soon cleared that and began to shine strongly. A weather front will cross our area later in the day bringing more cloud but no rain, which will mean a much warmer night than of late as the cloud will minimise the loss of warmth into the atmosphere. The breeze will veer a few degrees into the west today.

The centre of the anticyclone will slowly drift towards Scandinavia, which will result in the breeze overnight slowly changing direction to come from the northeast for the next few days bringing more dry and sunny weather and still around average maxima.

There was a significant change in the airstream on Friday as the high pressure to the southwest cut off the cold Arctic air stream and brought a slightly warmer air on a very light westerly, with a maximum movement, couldn’t call it a gust, of just 9mph. The temperature slowly rose to a maximum of 16.9C at 14.48, up 3C on the low of Thursday but still 2.2C below my 40-year average. It was a dry day with the UV level at the top end of ‘Moderate’.

Saturday began with muted sunshine but soon the sun rose above the thin cloud on the eastern horizon and began to shine strongly lifting the temperature to 6.4C at 08.00 after the minimum of 3.3C occurred 06.51, up 2C on the Friday low, but still a significant 5.4C below my 40-year average.

The centre of the high pressure is over the English Channel and is likely to give us a few days of warmer, sunnier and dry weather. The barometric pressure has risen another 2mb to read 1031.5mb at 08.00. As the anticyclone relocates the air will come predominantly from the southwest today.

The Arctic air from near Iceland meant a very cool day on Thursday that saw the thermometer struggle to reach 13.8C at 11.59 before cloud began to increase. This maximum was a significant 5.3C below my 40-year average and the coolest day since 3rd May. There were a couple of showers, the heaviest was at 15.00 when light hail fell in the precipitation amounting to 1.9mm. The sky cleared in the evening that saw the thermometer fall steadily downwards, reaching a chilly 1.0C at 06.51 early Friday, producing a ground frost, before the sun got to work. This low was a significant 7.7C below my average making it the coldest night since 25th April.

The rainfall total for September to date is 59.0mm, just 4mm below my 40-year average.

Friday began with glorious sunshine after dawn but following such a cold night the temperature had only recovered to 3.7C by 08.00. The soil temperature at a depth of 5cm had dropped to 6.8C at 08.00, the lowest since 28th April.

The high pressure in the Atlantic has extended over the UK with an increase of 13mb since 08.00 Thursday being the highest pressure since June, the reading at 08.00 was 1029.1mb. This change will cut off the flow of Arctic air and see the airstream direction slowly veer from northwest to west later in the day and tomorrow will come from the southwest, a much warmer direction.

The westerly wind was brisk all day on Wednesday gusting to 26mph, that with limited sunshine, produced a cool day. The maximum of 14.8C at 16.11, in late afternoon sunshine, was a significant 4.3C below my 40-year average and the coldest day since 2nd May. A squall at 17.15 produced 2.1mm of precipitation and very gusty winds that saw the air temperature drop 4C. It got even colder overnight under clearing skies that saw the temperature fall away to 4.4C at 04.49 early Thursday being 4.3C below my average and the coldest night since 29th April.

Thursday began with sunshine immediately after dawn that slowly raised the temperature to 7.4C by 08.00. Although the westerly wind will continue it won’t be as strong so although the thermometer won’t get much higher than on Wednesday it should feel less cold.

The recent low pressure system is easing away eastwards and the high pressure in the Atlantic is beginning to influence our weather. The barometric pressure has risen 6mb since 08.00 on Wednesday being the highest for a week reading 1016.2mb at that time.

Under the influence of a risk westerly breeze gusting to 21mph on Tuesday and variable sunshine in the afternoon it was no surprise to find that both the maximum of 17.9C and the very low minimum of 6.4C were below average at -1.2C and -2.3C respectively. The cold front arrived late afternoon and passed over our area at 18.30 bringing a heavy shower amounting to 3.9mm and a wind squall. The low of 6.4C made it the coolest night since 17th June.

Wednesday revealed a bright start to the new day with strong sunshine that lifted the temperature to 9.1C at 08.00. The wind dropped away overnight but was already beginning to strengthen from the west after 08.00 and will veer into the west northwest and northwest later in the day.

The barometric pressure has remained very constant over the last three days with 1010.9mb, 1010.2mb and 1010.3mb at 08.00 between the high in mid-atlantic and low to the northeast.