Month: March 2024

The glorious sunshine on Saturday lifted the thermometer to 14.8C at 13.54, being 4.2C above my 40-year average, before increasing broken cloud limited the sun. However it was a dry day, only the tenth this month. The low overnight of 3.8C at 04.29 was also above average (+1.3C), only the ninth this month.

Sunday revealed weak broken sunshine half an hour after dawn thanks to a bank of cloud low on the eastern horizon and then thin variable cloud limited restricted full sun.

Not only has the deep depression moved back west into the Atlantic but it has continued to fill having increased over 33mb since the minimum on Thursday. The barometric pressure in Marlborough at 08.00 was 994.4mb, a rise of almost 20mb over the three days. As a result of the rise in pressure, Sunday will be a quieter day than of late although with restricted sunshine thanks to variable cloud and thus not as warm as Saturday. The result of the low pressure systems relocating has meant the breeze on Sunday will come from the east, rather than the south, as for the previous three days, dragging cloud in from its traverse across the North Sea.

Friday produced many fewer showers than the almost continuous rain on Thursday, in fact after the two heavy showers in the morning there was no rain after 12.50, that allowed intermittent sunshine to breakthrough as the clouds thinned and cleared. As a result of the improvement after midday the maximum occurred at 14.30 with a peak of 12.2C being 1.6C above my 40-year average.The daily rainfall total of 3.3mm took the monthly rainfall total to 114.6mm or 187% of my 40-year average.

Thanks to the clearing skies overnight the temperature dropped away steadily to reach a minimum of 2.3C at 06.10, just before the sun arose. In fact that low allowed radiation fog to form in the River Ogg valley, which disappeared shorty after 06.3o only to be replaced with a bank of fog drifting in from the Kennet valley, however that had almost cleared by 07.10.

Initially Friday brought weak sunshine through the fog but after that had cleared we were greeted by strong, continuous sunshine.

The deep depression that was named Storm Nelson has developed into two less intense areas of low pressure that have been pulling away west into mid-Atlantic. As a result the barometric pressure has been rising steadily with the isobars, lines of equal pressure, opening out so Saturday will be a much quieter day with much sunshine. This will also see a change in the wind direction from south-southwest to southeast later today and be much calmer than of late.

The deep depression that was Storm Nelson on Thursday brought us winds gusting to 40mph and a substantial additional rainfall. The maximum did not get above my 40-year average with a peak of just 9.5C being 1.1C below average. The minimum of 4.8C occurred just after midnight, at 01.08, early Friday, however that was 2.3C above the long-term average thanks to the continuing cloud cover and southerly breeze. An additional 16.9mm of precipitation has taken the monthly rainfall totally 111.3m, which is 181% of my 40-year average or +49.9mm.

At the moment there are two previous years with greater March rainfall, namely 2018 with 130.9mm and 2023 with 163.3mm.

Thunder was heard at 15.58 and later at 17.10 as a line of intense rainfall, and numerous lightning flashes, were contained in a rain band moving northeastwards just to the west of Marlborough.

Friday gave us brief glimpses of sunshine after sunrise but also brief showers. This is likely to be the pattern for much of the day as the intense depression, named Storm Nelson by the Spanish Meteorological Service, is just to the west of Ireland and will still having considerable influence on our weather. After a quieter few hours overnight the wind is forecast to strengthen this afternoon before becoming calmer during the evening. The wind has backed a few degrees and is now coming from the south-southwest. At 08.55 the rain radar showed a brief gap in the shower activity this morning until the next line of showers arrives late morning, currently over west Somerset.

After a bright start to Wednesday it wasn’t long before the cloud built up and a significant squall arrived. The wind gusted to 32mph at 09.21 with soft hail, called grauple, being observed at 09.34. Over the next 25 minutes the thermometer dropped from 8.4C to 3.0C in the blast of cold, gusting air. The early peak of 8.5C at 08.45 was the maximum all day being 2.1C below my 40-year average. The minimum overnight of 1.9C occurred at 05.00 early Thursday that was 0.6C below my 40-year average.

The deep depression, then off the Irish coast, produced a rash of frequent shower lines that formed roughly concentric circles around its centre, over the UK. The total rainfall in the past twenty-four hours amounted to 21.7mm making it the wettest day since 17th February (27.1mm) and took the monthly total to 94.4mm, which is 154% of my 40-year average or +33m.

Thursday began with strong sunshine but by 08.00 shower clouds had built up and showers arrived that in between gave brief spells of sunshine.

The intense depression at 08.00 was just off the tip of Cornwall. As it closes in the shower activity will become more frequent with heavy rain and the wind building in strength and likely to exceed 50mph after midday. The centre of the anticyclone had a reading of 965mb at 08.00 while in Marlborough it read 976.1mb, the lowest barometric pressure since 9th February (974.5mb)

The advance effect of the deep depression off Ireland was felt on Tuesday as an extensive rain band produced the first spots of rain at 13.25 and finished just after midnight that produced 15.1mm of precipitation. This was the second wettest day in March and took the monthly total to 72.27mm, which is 118% of my 40-year average or +11.3mm, with much more to come on Wednesday. It was a warm morning until cloud built up before midday that saw the thermometer climb to 13.7C at 11.09, being 3.1C above my 40-year average. After the cloud and rain arrived the temperature dropped back. In the early hours of Wednesday, as the rain stopped and the cloud thinned, the temperature began to drop to a minimum of 4.2C at 04.40 being 1.7C above the long-term average.

Wednesday brought us glorious sunshine until 07.45 when advance cloud from the next weather front arrived and blotted out the sun.

The intense depression just off the south west coast of Ireland is at the moment continuing to deepen with a forecast centre pressure of 955mb this morning. The Spanish Meteorological Service have named this as Storm Nelson as it will have its greatest effect over that country. This intense low pressure system will influence our weather for the next two days with much more rain and strong winds, currently from the south. The barometric pressure here at 08.00 was 978.0mb, the lowest pressure since 9th February.

Both the Meteorological Office and BBC Weather forecast winds in excess of 50mph for a period on Thursday.