Sunday 26th April
After the very cold start on Saturday, following the sharp air frost, the temperature rose steadily to around 15.00 before levelling off and eventually reaching a maximum of 21.8C at 17.50 in glorious, warm evening sunshine. It was the warmest day since 19th September being a significant 7.5C above my long-term average. Under clear skies initially, the warmth slowly ebbed away, but just after 01.00 cloud began to drift in from the west that gave total cover by 02.00. A minimum of 2.6C was logged at 04.40, which was 1.2C below average.
Initially on Sunday the sun was muted after sunrise due to residual cloud on the eastern horizon but shortly after 07.00 was shining quite strongly through thin high cloud. The radar indicates that cloud will drift in again around 10.00 with breaks returning around 14.00 to lift the temperature well above the average again.
With no rain for a week, and that at the beginning of the month minimum, the ground continues to dry out as does the atmosphere. Another 4.3mm of equivalent rainfall was lost through evaporation from the ground and plant life yesterday whilst the humidity was exceptionally dry with a minimum of just 23.9% at 14.44.
The high temperatures this past week, combined with cool nights, have produced a considerable diurnal temperature range, the difference between day and night. The diurnal range Friday to Saturday morning was a considerable 21.9C compared to just 5.1C at the beginning of the month under a warm, moist southwesterly air stream.
The soil temperature at a depth of 5cm, read daily at 08.00, has been consistently below the 10C temperature for the past week thus not encouraging any tender plants to grow under protection or seeds to germinate. This morning, after a very warm day and a less cold night, the temperature had only dropped to 11.1C overnight.
The high pressure that has dominated air weather for a week is changing shape and position over the UK. Today the wind will initially come from the northeast before changing to a southerly direction this afternoon. By tomorrow morning there will be a significant change that will mean a northerly air stream arrives and a much cooler northeasterly by Tuesday.