Category: Commentary

Tuesday gave us the last of the warm, dry days as just after 14.15 cloud began to fill in and the temperature to drop. The sunshine of 5.4 hours, until this time, allowed the thermometer to rise to a maximum of 21.8C, which was 3.1C above the 36-year average.

There was a significant change in the wind direction that started late on Monday. After six days with the wind coming consistently from the north east it backed into the south west heralding a major change in the weather. No longer were we under the influence of an anticyclone to the east but approaching depressions arriving from the Atlantic.

Rain began to fall around 01.30 early on Wednesday with a heavier burst between 02.30 and 03.00 that amounted to 5.7mm in total making it the wettest day since 28th August. This brought to a halt 18 continuous days of dry and sunny weather. The total rainfall for September is currently 8.7mm when the average for September is 62.9mm.

The overnight cloud from the weather front minimised the loss of warmth into the atmosphere therefore it was a mild night with the thermometer not falling below 13.9C, which was 4.7C above the average.

Sadly there was no sun to greet the new day on Wednesday but thick, complete could cover. A cold front is approaching from the west so more rain is expected to arrive before midday. The air in a cold front is heavier or denser than the warm air so pushes underneath the warmer air that then rises and as it does so condenses and produces precipitation.

The light winds on Monday, still from the north east for much of the day, and 7.6 hours of strong sunshine, pushed the thermometer to a maximum of 24.3C being 5.6C above the 36-year average. Mid-Afternoon the light winds, with a maximum gust of only 9mph, very slowly backed into the north west after six successive days with northeasterly winds.

We have now enjoyed 18 successive dry days that equal the period 4th – 20th May.

Due to clearing skies overnight the thermometer fell away to a minimum of 9.2C, which was exactly equal to the September minimum average.

Tuesday arrived with sunshine as soon as the sun rose above the horizon. This will be the last of the very warm, sunny days.

The barometric pressure has now dropped to its lowest in September, at 08.00 a reading of 1010.9mb, heralding a significant change from our recent weather pattern in coming days as the anticyclone moves away to the east and depressions in the Atlantic approach our shores.

Sunday was another dry day with 7.6 hours of sunshine that again produced an above average maximum temperature (+3C) with a peak of 21.7C. The winds still persisted from a north easterly direction, the fifth consecutive day.

The overnight minimum was also above average (+1.2C) with a low 10.4C at 04.44.

Monday dawned with no sight of any sunshine due to fog that limited viability to 500m. Notably, the wind dropped very light around 02.00 and this morning at 08.00 the very light movement of air is still from the north east.

Evaporation this month now totals the equivalent rainfall of 44mm when the actual rainfall is still just 3mm.

The wind from the north east continued all day on Saturday gusting to 30mph at 13.46, which was the windiest day for almost a month. The computer trace of the wind direction from the anemometer shows an almost unbroken line for the past four days. This is unusual in our geographical position as the wind is frequently changing direction as the weather can arrive from all points of the compass.

Although the wind was stronger on Saturday the temperature rose higher than on previous days to reach 22.1C late in the afternoon, which was 3.4C above average.

We have now experienced 16 consecutive dry days.

Another mild night followed with the thermometer not falling below 13.3C, being 4.1C above average.

Sunday morning arrived with thick cloud still being driven on by a brisk northeasterly wind but continuing dry. The first glimpse of brightness occurred at 08.05.

Although the wind continued from the north east on Friday, a cool direction, the 8.7 hours of sunshine meant another above average maximum temperature of 20.4C, exactly as on Thursday (+1.7C). The peak gust of wind was 23mph, the strongest gust this month, as the low pressure over the continent eased northwards against the anticyclone to the northeast, increasing the pressure gradient.

Overnight the increased cloud cover also meant an above average minimum (+1.7C) of 10.9C.

Saturday dawned with thick cloud cover driven on by the the brisk and persistent north easterly.

The daily evaporation has meant the equivalent loss of 3mm of rainfall on recent days that means a total loss of 38mm whilst the total rainfall still stands at 3.0mm. We have now enjoyed 15 continuously dry days.