Sunday 10th May
There was very pleasant sunshine on Saturday, especially in the afternoon under light winds, that lifted the temperature to a maximum of 20.9C at 16.20, being 3.6C above the May average. A minimum of 8.2C was logged at 05.50 early Sunday, which was 1.2C above average due to cloud cover minimising the loss of warmth into the atmosphere. However, that was only part of the story, as the wind began to pick up speed after midnight with a peak gust of 24mph at 03.07.
Sunday arrived under total cloud cover and the wind still blowing strongly from the northeast. Outside it felt distinctly cool as the wind was producing a significant wind chill. At 08.00 the thermometer, which was shielded from the effects of solar radiation, read 9.3C whilst outside it felt more like 8.4C.
The squeeze has returned today as a result of a high pressure to the west and a combination of two low pressure systems, one over the Bay of Biscay and the other over southern Scandinavia. The air is rushing from the high pressure with a centre reading off 1030mb, to the centres of the two lows, both with identical pressures of 1005mb at 08.00.
The forecast surface pressure charts show a very mixed, complex situation in the week ahead as the depression will try and head south towards the UK that will continue to feed air from the northeast or north. During the second half of the week our air will have originated from around the Arctic Circle in northern Scandinavia. Mid-week will be especially cool with a possible frost early on Tuesday morning. Two cold fronts will bring the distinct change in air with the first crossing Monday night and the most active later on Tuesday as three centres of low pressure settle between the North Sea and northern Scandinavia feeding down the very cool air between them and the high to the west.
There is little cheer for gardeners this week thanks to depressed temperatures by day and night, with little likelihood of significant rain in the days ahead, although there is the possibly of light showers on Wednesday as a ‘trough’ of low pressure passes over the UK. As the trough traverses the UK the wind will strengthen considerably during daytime. The rainfall total for May stands at 5.2mm whilst there is equivalent loss of rainfall due to evaporation from the ground and plant life of 27.4mm. Yesterday the loss was an equivalent 4mm, the highest this month, so no wonder the gardens are very dry.