Category: Commentary

Friday was the sixth successive day that the maximum was below average. The peak of 7.7C, logged at 12.04, was a degree higher than on Friday but still 3.0C below my long-term average. Cloud thickened in the afternoon but although there were a few spots of rain observed around 15.00 it was not sufficient to be measurable. The cloud overnight meant no air frost, for the first time in four days, as the thermometer did not sink below 1.1C, logged at 06.15 early Saturday, also below average at -1.6C.

Saturday dawned with a mostly cloudy sky although there were brief glimpses of the sun just after 08.00 by which time the thermometer had eased upwards to register 2.3C. However, the brisk northeasterly breeze produced a wind chill again so outside at 0800 it felt more like 0.8C.

At the middle point of March the total rainfall is just 1.5mm set against the equivalent loss of rainfall through evaporation, from ground sources and plant life, now totalling 19.8mm.

The anticyclone has strengthened with the pressure having risen to 1022.2mb at 08.00, up 13mb since yesterday at that time, which is beginning to cut off the Arctic northerly air although the air stream from the northeast is from a cold Continent and from as far east as Russia, which is still very cold. Unfortunately, I think it will not be until Tuesday, from the forecast synoptic charts, that there will be any significant warmer weather, and then only modest until later in the week.

The peak of 6.9C on Thursday made it the coldest day this month, also since 18th February (6.7C), being exactly 4C below my long-term average. This maximum was logged at 15.16 between the cloud activity that built up after 11.00 to the north of our area, and slowly tracked southwards. Under broken cloud in the evening the temperature eased downwards dropping to -0.1C at 21.58 and falling to a minimum of -3.2C at 04.35 early Friday, which was a significant 5.9C below my long-term average.

The weather station sends a pulse to the ‘cloud’ very 5 seconds and makes a recording every minute, which showed the thermometer beginning to rise significantly around 05.30, also tracking back in the cloud radar it is at that time when cloud and the fog began to drift southwards across our area, also confined by the humidity also rising at that time.

Friday morning revealed foggy conditions that limited visibility initially to 200m but began to thin after 07.30 with the thermometer having risen to -0.8C by 08.00.

The Old Farmer’s Almanac began publishing full moon names in the 1930s. I discovered that Native Americans called this last full moon of the winter the worm moon after the worm trails that would appear in the newly thawed ground. Other names include chaste moon, death moon and sap moon, after the tapping of the maple trees.

We have a couple more days of this cold weather but by Monday we are likely to see the temperature begin to recover to around the above normal for mid-March and later, hopefully above.

After a mainly cloudy morning on Wednesday the afternoon brought more showery conditions that on two occasions very briefly contained small hail, less than 5cm in diameter, observed at 13.50 and 14.40. On the second occasion the temperature dropped by almost 3C from its high of 7.1C. This peak made it the coldest day this month and was 3.6C below average.

The temperature overnight very slowly eased downwards but did not drop below freezing until 03.13, with a minimum of -0.3C at 03.51, it then rose above freezing at 04.15 rising to 2.3C by 08.00.

The start to Thursday was initially cloudy but the sun broke through just before 08.00. The showery, cool weather will continue thanks to the run of cold Arctic air squeezed between the low over the Continent and the High over Iceland brought on a northerly flowing quite brisk in the morning. The temperature of 2.3C at 08.00 felt more like 0.2C outside at that time thanks to wind chill. The brisk wind will become lighter this afternoon as the low eases away and the high gets closer.

The Met Office has been trialling aircraft-generated data that has been described as “successful” in improving weather forecasting. They have been receiving information from thousands of aircraft over the last two years as part of plans for improving forecasts. They have been taking the high-volume data feed, which provides real-time atmospheric data, that includes factors such as temperature and wind speed, from different points in the atmosphere and ingesting this data into the Met Office Global Model.

The Met Office representative said “Early results following this trial suggest that the integration of this data will have a significant positive impact on our global model, allowing us to achieve greater precision and contribute towards further advances in forecasting skill”.

Tuesday was the coldest day of the month, also since 18th February, as the Arctic air dominated our weather. The maximum of just 8.1C logged at 14.31 was 2.6C below average, however, the wind chill from the brisk northeasterly wind, gusting to 19mph at its peak, meant outside it felt up to 2C colder.

The intermittent sunshine gave us the peak solar radiation of the month, with a high of 715W/m2 at 13.13, before cloud became more consistent, so the sun is getting stronger, but it didn’t feel like it! Any warmth slowly dissipated into the atmosphere as the late afternoon and early evening progressed but after reaching a low of 1.3C at 20.08 the thermometer did an about turn and started to climb back up as a large sheet of cloud drifted down from the north, reaching 3.9C at 00.01. The temperature then began to fall again to reach a minimum of -0.7C at 05.51, being 3.4C below average and producing a short lived air frost.

The UV level rose to its highest at 2.6, but still at the top end of ‘Low’.

Wednesday began with high broken cloud but no early sunshine until after 08.30, although bright. The breeze today will be lighter so minimal wind chill.

The cooler days and nights have seen the cold seep back into the ground again with a temperature at 08.00 reading 8.2C, 5.9C and 2.7C today respectively from the thermometer 5cm deep in the soil. The maximum daytime temperatures also show the effects of the Arctic air with 17.4C, 12.8C and 8.1C yesterday respectively.

The cold air still streams down from the north between the high, now over Iceland, and the low over Continent, with the wind veering from northwest to north today and possibly back to northeast later.

N.B. Please ignore the maximum gust of wind of 83mph, given in the live weather data panel, supposedly logged at 00.18, it didn’t happen! Occasionally there is a glitch in the 5 second automatic download. I am still waiting for Davis to provide a method for me to access and correct such glaring anomalies, as also are others.

Monday was the last of the days, until next week, when the maximum rose above the average for March with a peak of 12.8C at 13.37 being 2.1C above the long-term average. After around 13.00 the cloud, associated with the depression over France, built up producing misty conditions.

The first of the rain in March fell as a very light shower just after 09.00 on Monday but more registered on the automatic rain gauge between 02.00 and 04.00, that totalled 1.1mm, being the first precipitation this month.

The forecast cold front passed our way in the early hours of Tuesday crossing the south coast around 08.00. Behind it the temperature fell to a low of 4.3C at 06.37 being 1.6C above average, however, the arrival of the Arctic air, on a northeasterly breeze, produced a wind chill that meant outside at 08.00 it felt more like 3.1C rather than the air temperature of 4.6C.

The clearer air currently behind the cold front will likely produce some modest, short-lived sunshine, between variable cloud, but the temperature will be noticeably depressed compared to the unseasonal warmth of last week. However, there is another band of thicker cloud streaming south behind the front thus blocking out the early sunshine for much of the day.

Currently the air is streaming across the country from the north on a northeasterly breeze having originated around Greenland. It is being propelled towards us by a low pressure system over Scandinavia, with the air circulating anticlockwise, and a high pressure system over Iceland with its associated air mass rotating clockwise, so therefore squeezed between the two weather systems thus its direction and increased speed over recent days.