Tuesday 5th May
The cooler northeasterly airstream arrived on Monday that resulted in depressed temperatures by day and night. There was variable sunshine but that was not sufficient to push the maximum temperature above the early May average with a peak of only 15.3C, being -2.0C, logged in the early afternoon at 14.29, before more cloud arrived. The past night was also cool with a minimum 6.3C at 05.41 early Tuesday. The low was 0.7C below average due to clear skies and almost calm conditions overnight.
The UV value of 5.2 again on Monday indicated that the ultraviolet light was at a ‘High’ strength for the second day in succession.
Thick fog had formed in the early hours of Tuesday that limited visibility to 200mm, when observed at 06.15, however, the sun could be seen through the fog beginning to quickly disperse it so that the conditions became just misty by 07.00. The wind has backed a few degrees today, coming from the north predominantly, and has picked up in strength which will result in a cool day ahead. In fact, first thing there was a wind chill that when the temperature at 08.00 read 8.2C in a radiation shielded thermometer, the wind chill meant it felt more like 7.5C outside.
The rest of the working week will be cool, especially on Wednesday, as a brief rush of Arctic air crosses the country making it feel very cool outside. This will be due to a high pressure system extending from the Azores to Iceland, just to the west of the UK, which will feed the cold air around its eastern flank before a low pressure system arrives between Scotland and Iceland on Thursday, cutting off the direct flow from the Arctic but still a very cool flow of air. This will result in temperatures slowly recovering to near average by Friday and over the weekend.
This will be in such contrast to the forecast for parts of California and Sacramento when 48 inches of snow and 80mph winds are forecast over high ground this week.