Category: Commentary

The first day of Spring on Thursday gave us the warmest day all month also since 19th September (22.3C), which was a significant 9.1C above my long-term average. We have just enjoyed the warmest night this month when the thermometer did not sink below 8.8C, logged at 06.29 early Friday, being 6.1C above the long-term average. It follows that it has been the warmest start a day at 08.00 this month with the thermometer having edged back upwards to 9.5C.

The other feature to record yesterday the highest all month was the loss of equivalent rainfall through evaporation from the ground and plant life that gave a daily total of 2.5mm. The loss for the month is now a significant 30.7mm set against the minimal rainfall of 1.5mm.

There is a significant change in our weather for Friday. The recent high pressure, that dominated our weather for well over a week, has given in and allowed the depression, that has lingered around Iberia for four days, to take charge of our weather today. The barometric pressure dropped 12mb over the last twenty-four hours, reading 1008.1mb at 08.00, the lowest since the 13th. The cloud built up yesterday and overnight and today will minimise any sunshine, if any, that is likely to be weak. A weather front and its associated rain band will make progress over the UK later this afternoon and evening, the rain radar indicates that this could be the wettest day for almost a month with a significant fall. Rain is currently over Cornwall and the radar shows minor outbreaks coming in from the south coast, currently heading toward Basingstoke, on a brisk southeasterly. As the depression edges closer, the pressure gradient will increase with a consequent strengthening of the wind as the day progresses.

The maximum of 16.6C at 15.11 on Wednesday made it the warmest day since 25th November (17.1C) and a significant 5.9C above my long-term average. It felt very warm in the glorious sunshine, especially as the breeze from the southeast, a much less cold direction that recent northeasterlies, was much lighter, only just into double figures, with a peak gust of just 11mph on one occasion.

Under the sunshine and light breeze another 2.1mm of equivalent rainfall was lost through evaporation from ground sources and plant life, now totalling 28.2mm, against the minimal rainfall for March of 1.4mm, when the 40-year average is 62.9mm.

So far in March we have only had two days when there was precipitation. The coming weekend will see more unstable weather arriving as the high-pressure relinquishes control and the depression, now over Iberia, approaches the country, with cloud and lower temperatures also the possibility of light rain.

The UV level rose again, at its peak, up to the ‘Moderate’ category.

The past night was much less cold than recent nights with the thermometer not sinking below 6.1C logged at 05.56, making it the warmest night since the 5th (6.4C) due to the warmer air mass and broken cloud overnight limiting loss of warmth into the atmosphere.

Spring Equinox. Some research reveals that the word ‘equinox’ comes from the Latin language and means equal night.

It would be easy to assume that day and night would be of equal length of 12 hours each. However, that is not entirely true.

At the equinox, the measurement is taken from when the centre of the Sun is at the horizon and there are 12 hours between sunrise and sunset.

The top edge of the sun is visible first at sunrise and last at sunset. Due to refraction, there is still light for a short time even when the sun is no longer visible. This adds a little extra time to daylight hours.

The concept of the spring equinox was celebrated by ancient civilisations such as the Egyptians, Greeks and Persians, often associated with rebirth of nature and fertility rituals.

The high on Tuesday of 12.3C, logged at 15.17, was the first above average maximum since the 10th being +1.6C. This increase in warmth was very welcome and due to the wall-to-wall sunshine, although in the brisk easterly breeze it still felt chilly. The past night, under clear skies and little breeze to stir up the air mass, gave us 5 hours of freezing conditions from 01.57 to 06.53 early Wednesday producing another air frost, but not severe, with a minimum of -0.8C at 05.59.

By 08.00 on Wednesday the sun had got to work over the previous hour so that by 08.00 the thermometer had risen to 3.9C between broken cloud. Today will give us a sunny morning but more cloud is forecast to drift up from the south to give us weaker sunshine in the afternoon.

A significant change in the wind direction to southeast today will continue the increase in warmth, so outside it will feel very much warmer than previous days.

The high pressure is still fending off the advances of the deep depression just off the coast of Iberia. The barometric pressure has fallen another 3mb since yesterday, but down 5mb since the high on Sunday.

The equivalent loss of rainfall through evaporation from ground sources and plant life rose to 2.4mm over the past twenty-four hours. This was the greatest loss since 18th September under the continuous sunshine, brisk wind and increased warmth. There is a possibility of some rain on Saturday but the forecast of quantities is not confident at this time.

Monday was a day best forgotten as regards the weather as it was dull, gloomy and cold all day. Under the persistent easterly wind, gusting to 20mph at its peak and with no sunshine the thermometer struggled to reach 6.6C at 15.26, which was a significant 4.1C below my long-term average and made it the coldest day this month. The brisk wind from the east meant wind chill was again in evidence that meant outside it felt almost 2C cooler than that indicated on a shielded thermometer.

Monday, under the gloomy, thick cloud produced a maximum solar radiation of just 251W/m2, being the lowest all month and the UV light, not surprisingly, was back into the ‘Low’ category at 1.7, the second lowest all month, the 10th logged peak UV at 1.6.

As expected under a clearing sky overnight, as the residual cloud from the two weather fronts eased southwards, the temperature dropped away reaching a minimum of 0.3C at 06.19 on Tuesday before the rising sun got to work. This low was 2.3C below average and although it produced a ground frost, as the thermometer did not drop below zero, there was technically no air frost.

Tuesday brought a glorious start to the new day with the red sun at sunrise beginning to shine strongly as it eased above the horizon, this lifted the thermometer to 3.2C by 08.00. As the anticyclone repositions over Germany the wind will veer a few more degrees from east to eastsoutheast as the day progresses, indicating that a change is getting closer, a much less cold direction.

It has been a very dry month with no rain expected until possibly the weekend as only 1.5mm of precipitation has been recorded. By contrast, the equivalent loss of rainfall through evaporation from ground sources and plant life now totals 24mm.

The cold air trapped under the high pressure gave us another cold day on Sunday. The thermometer rose to a peak of 7.9C at 13.28, following a cold night, before more cloud arrived drifting down on two weather fronts, the low was 2.8C below my long-term average. The UV light peak was 3.1, just into the ‘Moderate’ category again.

The past night was much less cold thanks to the cloud brought on the two weather fronts so a minimum of 4.0C at 06.50 early Monday was in fact the first night with an above average minimum, with no frost, air or ground, being 1.C above my long-term average.

Monday dawned dull with total cloud cover from the residual cloud thanks to the two weather fronts that arrived on Sunday. The cloud should slowly ease later in the afternoon with some possible brightness. The wind was coming from the northeast to start the day but is forecast to veer a few degrees later today and then come from the east.

The humidity at 08.00 on Monday was 83.1% thanks to the air steam having travelled over the cold North Sea picking up moisture on the way. When the air stream veers into the east and then southeast on Tuesday it will be travelling over the Continent that is much drier, therefore the humidity will drop tomorrow with consequently much less cloud and the likelihood of sunshine with hopefully, a slight rise in temperature.