Category: Commentary

The barometric pressure fell rapidly on Wednesday with a resultant increase in wind strength. The cloud associated with the depression meant a sunless day, the third this month. The temperature hovered around 9C for most of the day but in the evening eased upwards to give a maximum of 10.6C at 18.32.

The peak gust in the past twenty-four hours occurred at 02.20 with a gust of 42mph.

Thursday arrived with variable cloud and short bursts of sunshine. The minimum barometric pressure reached was 989.7mb. The pressure is now rising rapidly as the depression eases away.

There was such a contrast in solar energy over the past two days when our contribution to green energy from solar panels was almost 20kwh on Tuesday but only 1.4kwh on Wednesday, However, as far as the country is concerned where the solar energy was diminished it was compensated for by energy from wind turbines.

Tuesday that brought 7.5 hours of sunshine was a glorious day with the thermometer rising to a maximum of 12.0C, which was 1.5C above the 37-year average and the warmest day since 25th February. The wind was predominantly from the southwest and brisk with a peak gust of 17mph.

Thin high cloud began to mask the sun just after 16.00 as the advance notice of the approaching depression. Around the same time the wind began to back and come from the south.

The barometric pressure has been dropping dramatically over the most twenty-four hours loosing 12mb in strength as a depression off the west coast of Ireland deepens and approaches the UK. By 12.00 it is forecast to have a central pressure of just 965mb, which is extremely low.

Overnight the cloud continued to thicken and the first rain triggered the automatic rain gauge just after 05.00 that amounted to 1.2mm by 08.00 on Wednesday. The wind began to strengthen around that time with a peak gust of 26mph at 07.15. Increased cloud cover meant a mild night with a minimum of 5.3C being 3C above the average.

The very light wind on Monday with a maximum gust of just 10mph, was predominantly from the west-northwest and then west, which is a warmer direction than from the Arctic north recently. As a consequence, and aided by 5.7 hours of sunshine, the thermometer rose to its highest in March with a maximum of 11.1C. This was 0.6C above the 37-year average, the warmest day since 28th February and a rise of 5C over previous days.

There was an overnight air frost, but much less severe than the previous night, with a minimum of -1.1C at 06.12 on Tuesday.

It was a delight to see and feel the the sun shining brightly after sunrise that lifted the temperature to 3.4C at 08.00.

The high pressure has been retreating over the last three days with a current reading at 08.00 of 1021.9mb, the lowest since 24th February. A depression is queuing up in the Atlantic to take its place so Tuesday will be the last of the settled days. The wind has now backed further and currently coming from the southwest although currently very light.

Sunday brought after midday 5.7 hours of sunshine but the light breeze from the north meant the temperature was depressed with a maximum of only 6.1C being 4.4C below average. The UV level of 2.3 was the highest since 11th October being at the top end of ‘Low’.

During the late afternoon the thermometer began to fall again under clearing skies but fell rapidly during the evening. The air reached freezing point (-0.1C) at 19.36, -1.0C occurred at 20.05 and -3.0 at 22.54 before the minimum of -3.3C was logged at 23.30. Thereafter, the thermometer began to recover so that by 08.00 on Monday the temperature had returned above freezing with a reading of 0.7C with no evidence that during the late evening a hard frost had occurred. The thermometer edged above freezing at 03.15 before briefly falling back to -0.1c just before dawn.

Monday after dawn saw complete cloud cover. The anticyclone has been retreating with the current pressure at 08.00 of 1025.8mb, down 10mb in 24 hours. The centre of the high pressure is now over the western side of the Bay of Biscay that will bring air movement today from the west – a significant change in direction.

Although the maximum on Saturday was 1C up on Friday, which was 1C up on Thursday, it was a cold day. The thermometer eventually rose to a peak of 6.4C, which was 4C below the 37-year average. I read yesterday that the plunge of cold air from this direction is referred to as the Scandinavian Surge. The breeze continued from a northeasterly direction but less brisk than of late with a peak gust of 13mph.

The past night was very similar to the previous night in that the thermometer dropped away to a minimum in the early hours before rising again as cloud drifted in. The minimum of -1.3C at 02.27 Sunday morning produced a short lived air frost so that by 08.00 on Sunday the thermometer had recovered to read 1.2C.

Sadly no sun was evident after sunrise on Sunday due to the thick cloud. The wind, has backed slightly into a more northerly aspect as the centre of the anticyclone is over the southwest coast of Ireland at midday. The air today is much drier than of late with the wind now passing over more land than sea with a humidity of 72% at 08.00, not seen since 12th February.