Saturday 25th April
The lighter winds, and again wall to wall sunshine, meant an even warmer day on Friday that saw the thermometer rise to a peak of 19.8C at 16.39, being a significant 5.5C above my long-term average. I expected another cool night but not so cold, the thermometer dropped to -2.1C at 05.35 being a significant 6.0C below average. In more detail, the thermometer dropped to freezing (-0.1C) at 03.03 and did not rise above freezing until 06.48, almost an hour after sunrise in Marlborough at 05.51, so almost four hours of sub-zero temperatures. The Met Office forecast was for another night close to freezing but not so sharp a frost and for so long.
The sun rose initially through variable cloud on the horizon, the thermometer struggled to recover to 5.2C by 08.00, making it, not surprisingly, the coolest start to a new day at that time since the 13th. There is likely to be a subtle change in wind direction today, with a suggestion of a more southeasterly component, that will bring us another fine, warm day with the thermometer possibly reach 20C at its peak and hopefully a less cold night to follow. A narrow band of cloud began to drift in from the west just after 05.00, high and broken, that is likely to clear around 10.00.
The anticyclone is still dominating our weather and has expanded from near Iceland to the Azores. The forecast surface pressure charts indicate that there will be little change until later next week, as a result the fine, dry conditions will continue, with little or no rain in the forecast.
The very dry conditions on Friday saw the humidity level drop to a minimum of just 34.7% at 16.30 with 4.3mm of equivalent rainfall lost due to evaporation from the soil and plant life, the greatest loss since 17th August last year during the heatwave conditions. This morning the humidity at 08.00 read 74.6%, also the lowest since the heatwave conditions in August last year.