Category: Commentary

After a very wet morning the intense rain from the weather front eventually ceased just after 11.30 adding another 10.8mm to the monthly total that now stands at 76.2mm being 8.2mm above the long-term average. Due to the hang back of cloud from the weather front that dominated the afternoon the thermometer only rose to a maximum of 9.3C, but this was 1.0C abject the average. Overnight the temperature remained quiet stable around 4.5C but as the last of the cloud cleared it dropped after 05.15 to reach a minimum of 3.2C at 07.20 early Thursday.

Thursday saw the last of the cloud disappearing eastwards over the horizon with the sun making an appearance just after 07.45. The humidity at 08.00 was 84%, the lowest since the 17th, as the drier air from the anticyclone arrives.

The large area of high pressure in the eastern Atlantic is today throwing a ridge of high pressure over the UK having risen 6.4mb since yesterday. With the barometric pressure continuing to rise as the day progresses, thus squashing out any showers, although cloud is likely to build after midday as the temperature rises due to the moist air condensing as it rises into the cooler high air.

This change in the position of the anticyclone and its associated ridge has seen the wind veer from the west yesterday into northwest overnight and likely into the north-northwest day this being a cooler direction it will moderate any temperature rise although much sunshine is expected. It is not a cold air stream, although from the northwest, as it originates in the northern sector of the Atlantic, not from the Arctic region, as the air travels clockwise around the high pressure dipping down across the UK. The ridge is acting as a blocking high keeping the next depression at bay, and likely to for the next few days.

Tuesday was a splendid day with much sunshine that although the wind came from the northwest, a cooler direction, saw the thermometer climb to a maximum of 10.6C at 14.32 being 2.3C above the long-term average. The UV strength rose to a peak of 1.5 between 12.00 and 14.00, the highest level since 31st October, so evidence that the sun is getter stronger. Therefore, it was not surprising that the level of daily evaporation from plant life and the ground was equivalent to a loss of 1.02mm of rainfall.

The warmth slowly dissipated during the evening, to level out just before midnight with a temperature of 2.9C, and reached a minimum of 2.7C at 04.10, being 0.9C above average. The temperature had recovered to 5.4C by 08.00 as the cloud had thickened ahead of the rain bands.

Two weather fronts have combined this morning to bring us a minor disturbance between the sunny days, that will moved eastwards, indicating a drier afternoon. The first rain drops were observed this morning at 06.35 with steady rain following that by 08.00 totalled 3.5mm with a couple of hours of rain still to come.

The forecast synoptic charts show an area of high pressure moving closer to the UK tomorrow, with a ridge developing across the country, which is likely to bring us a few dry and sunny days. This will form a blocking high fending off the forecast deep low pressure system developing to the northwest.

Monday brought us a very sunny morning that was spoilt by the two short but heavy showers around midday. These were from the two rain bands that the rain radar indicated were over mid Wales at 08.00 and heading our way. The first shower was intense at 12.30 and just after it started small hail (less than 5mm in diameter) was observed and the temperature dropped almost 3C within ten minutes from a peak of 12.3C. Before the rain arrived this was the warmest part of the day with the maximum of 12.3C at 12.29 being 3.9C above average with the thermometer around 11C for most of the afternoon. It was also at this time the peak solar radiation was logged at 673 W/m2 being the highest all month and in fact the highest since 7th October, so perhaps Spring is on its way.

The temperature overnight stabilised around 7C until dropping after 03.00 to reach a minimum of 4.5C at 06.58 early Tuesday, as the cloud began to thin, which was 2.7C above average.

Tuesday revealed the thick clouds from the back edge of the recent weather front over the eastern horizon and easing eastwards. The barometric pressure has also risen a few millibars as a short-loved ridge, which will calm things down today bringing minimal rain and calmer conditions. The reading at 08.00 was 1012.6mb. The wind has veered a few degrees, from the southwest yesterday to west-northwest for much of the day, a slightly cooler air flow for much of the day, that will limit the rise in temperature, but mostly dependent on the amount of sunshine we receive.

The forecast pressure charts show an expected rise in pressure over the next few days, spoilt by a minor disturbance around midday tomorrow, that should bring us much more sunshine up to the weekend and calmer conditions. This will be the result of a high pressure system in the Atlantic, developing off the coast of Iberia, and slowly edging our way.

The weather on Sunday was best forgotten as the morning was dull with thick cloud from the nearby depression. The first spots of rain were observed at 12.02 but no measurable rain was recorded until just after 13.30 when it was almost continuous, heavy just before and after midnight, producing a daily total of 18.0mm. This additional rainfall took the monthly total to 56.3mm when the long-term average is 68.0mm. There was a period of heavy and continuous rain between 23.00 and 01.00 and another just after 05.00 today.

However, it was another mild day and night with the maximum of 10.6C logged at 12.43, just before the real rain started, being 4.3C above average and the minimum of 8.3C recorded at 06.59 early Monday being 6.4C above average.

The wind increased in strength during the afternoon and into the early evening with a peak gust of 33mph 18.57, before slowly dropping away.

Monday at first light saw the back end of the weather front, with its associated thick cloud, slowly edging eastwards. The rain stopped just after 07.30 and the cloud began to thin. The rain radar shows a narrow band of heavy rain, currently crossing mid-Wales, and possibly heading towards us on a southwesterly air flow, that might produce some precipitation around midday.

The day will improve as the cloud cover continues to thin and break. The barometric pressure charts show the likely hood of a temporary ridge moving in on Tuesday to give a fine day before sunshine and showers return on Wednesday.

The maximum of 13.8C on Saturday, thanks to the several hours of sunshine, made it the warmest day since 1st December (13.9C) and was 5.6C above the long-term average. The westerly wind was brisk with a peak gust of 15mph. The past night was the coolest for four days with a minimum of 5.3C at 21.44 late Saturday evening which was 3.7C above the average.

Sunday revealed another cloudy start to a new day with the wind brisk and the temperature having recovered to 8.6C by 08.00 with the wind having backed into the south for much of the days. The first rain band shown on the rain radar at 08.30 was just crossing Cornwall and about to reach Dartmoor with indications of heavy rain. The forecast is for the first rain to arrive here around midday.

The deep depression just off the west coast will continue its track northeastwards to be between Iceland and Scotland this evening and as it gets closer the wind will rise and substantial amounts of rain can be expected as the forecast shows two weather fronts crossing the country by evening. The barometric pressure rose 15mb over the past twenty-four hours but as the centre of the depression gets closer, by tonight the pressure will have dropped 15mb. As the depression relocates the wind, that for much of the day will come from the south, will veer a few degrees to come from the Southwest.

The intermittent sunshine over the last few days, and higher temperatures, has seen the first of the spring flowers opening, providing a splash of colour, the image is of crocuses in my patio garden.