This is the outlook for the next four weeks using the JMA model from the Japanese Met Agency. This is not a forecast but an outlook. I have rotated the images and added a red line so you can see the UK and also added the weeks for each of the three images. Oranges colours is high pressure area’s and Blues is low pressure areas.
Week 1 26th April to 2nd May.
High pressure is over the UK, the JMA thinks high pressure will build to the North of Scotland. I think this will happen but will be early May before this happens. So overall it will be mainly dry but with the low pressure nearby in the Atlantic this will bring a spell of wet weather. (I believe sometime during Sunday) Temperatures will be around 1 c above average for the end of April.
Week 2 3rd May to 9th.
High pressure over the UK with low pressure systems to the East and West of the UK. This setup will bring around average temperatures and with rainfall around average if not slightly below.
Week 3 and 4 10th May to 23rd.
This two week period looks like quite a slack period of pressure bringing temperatures slightly above average with above average rainfall.