Category: Commentary

Tuesday brought us 6.5 hours of sunshine that brought very warm air on a brisk southerly breeze, gusting to 24mph, that lifted the temperature to a maximum of 24.3C, which was 3.3C above the 36-year average. It was a dry day with the UV level briefly peaking into the ‘Very High’ level, the first occurrence since 5th August.

A dry, very mild night followed with the thermometer not falling below 15.6 at 01.33 Wednesday, which was 4C above average.

Wednesday morning heralded a distinct change in our weather. Initially, before the sun rose above the horizon, there was an impressive sky scene with broken cloud illuminated by the sun just before sunrise and blue sky but by 06.05 cloud arrived that covered the entire sky and rain began to fall. This was the front edge of an extensive rain band that currently reaches from London westwards to the tip of Cornwall. There was just five or so minutes of very weak sunshine from the eastern sky before the sun was obliterated.

The barometric pressure has dropped to its lowest since 27th June with a current reading at 0800 Wednesday of 1003.5mb. This heralds a period of disturbed weather as today the Irish Meteorological Office announced that Storm Ellen was approaching Ireland from the Atlantic bringing very strong winds and heavy, extensive rain. Storm Ellen contains remnants of Tropical Storm Kyle after it crossed the Atlantic.

With the breeze still coming predominantly from the south on Monday the warm air mass lifted the maximum temperature to 24.1C being 3.1C above average during the 6.6 hours of strong sunshine. It was a breezier day with a maximum gust of 20mph, the strongest gust since the 12th.

A less cool night followed, in fact a mild night as the thermometer did not fall below 14.5C beginning to rise again at 06.18 on Tuesday.

Tuesday morning after dawn saw a bank of cloud or fog in the eastern horizon that initially obscured the sun but just before 07.00 the sun began to rise above the cloud and provide a sunny start to the day.

Rainfall for August stands at 10.3mm (average is 66.7mm) whereas the evaporation total is the equivalent of 48mm of rainfall.

Sunday morning saw bright intervals and occasional glimpses of the sun that lifted the temperature to 21.8C, just above average. There were a few spots of rain mid-afternoon but not measurable so recorded as a ‘trace’ that soon evaporated from hard surfaces.

Overnight the thermometer steadily fell away to record a minimum of 12.9C being 1.3C above average but the coolest night since the 7th. As a result of the humid air mass still prevalent and the lower temperature fog formed so that at 06.30 on Monday morning it was thick with visibility down to 100m. However, it was noticeable that after that time the fog began to slowly thin so that by 08.00 visibility had improved to 1,000m.

With lower temperatures by day and night the land has also been slowly cooling. The soil temperature at a depth of 5cm has fallen from a peak of 24.3C on the 12th to 17.1C on Monday, always recorded at 08.00.

The barometric pressure has been falling over the past three days and today with a reading of 1007.7mb at 08.00, is the lowest during August.

The mist and murk from the depressingly low, thick cloud was even more persistent and dense on Saturday than during Friday producing another sunless day. The solar energy level was at its lowest since 27th February.

The air continued to be humid and with the lower temperatures than last week produced the condensation that formed the thick cloud and bouts of drizzle along with a couple of very light showers just after midnight amounting to 0.7mm.

Saturday was an unusual day as the temperature continued to fall away until 09.45 when it slowly began to rise reaching a maximum of 17.8C at 23.39, not during daylight hours. The minimum of 17.1C occurred at 03.39 in the early hours of Sunday before the thermometer began to rise again reaching 17.9C at 08.00 Sunday.

In my report on Saturday I referred to the diurnal temperature being the temperature range between day and night. The variation over the past twenty four hours was minimal at 1.6C.

Sunday saw the thick cloud again draping the Marlborough Downs with visibly down to 300m but shortly after dawn it slowly began to lift and after 07.30 a few brief bright intervals occurred before the cloud filled in again.

Friday was the first day since 4th July when no sunshine was recorded due to the continuous thick, low cloud. Professionals on the tv seem to frequently refer to this as mist and murk, which sums it up well. During the day and past night there were frequent very light showers and light rain or drizzle that amounted to just 3.8mm.

Unusually the peak temperature was only reached in the early evening at 19.22 with 18.8C, the first below average maximum since 3rd August. The other interesting point to note is that the diurnal temperature, that is the difference between day and night, was just 3.3C with a minimum of 15.5C being 4C above average.

Not surprisingly the solar energy was the lowest since 10th March when August is supposed to be a summer month. The UV level never rose above ‘Low”.

Saturday arrived with no change from the low, thick cloud draping the Marlborough Downs and Savernake Forest, visibility varying between 1,000m and 2,000m.

It is interesting to note the falling away in temperature each morning at 08.00 from the peak on Wednesday with 22.1C, 19.6C, 16.3C and today 15.6C.