A quick look at the JMA from the Japanese Met Agency. Please note this is a general outlook from the JMA and my understanding from the models.
Week 1 10th to 16th August
High pressure ridge builds over the UK bringing very warm air moving up from Spain with dry conditions.
Week 2 17th to 23rd.
This period see’s high pressure to the North and South of the UK with a low pressure trough in the mid Atlantic. I see South westerly jet stream bringing some mixed weather with rain and showers and temperatures in the high teens.
Week 3-4 24th to September 7th.
This is a two week period with high pressure across the North Pole and a low pressure in the Atlantic. I see westerly’s setting in again bringing cool mixed conditions.
So from this I don’t see a great end to August and it looks like this mixed weather continuing into early September.