This is the outlook for the next four weeks using the Japanese Met Agency Model. It’s not a forecast but a general outlook. I added 3 images together and rotated them. I have added a red line so you can see the UK. Blues are low pressure systems, oranges is higher pressures.
Week 1 14th to 20th September.
Low pressure in the Atlantic just to the West of the UK and high pressure over Scandinavia. This looks like bringing some showery days with some heavier and prolonger spells of rain towards the end of this period. Temperature around normal on a South westerly air flow.
Week 2 21st to 27th.
A low pressure trough in the Atlantic will bring some periods of showery and sometimes wetter days. The high pressure just to the South of the UK will bring southern England a little drier conditions. Temperatures will be around average on a South westerly airflow.
Week 3-4 28th 11th October.
A small low pressure trough in the mid Atlantic with average pressure over the UK. This will bring mainly a drier period with the odd shower. Average temperatures on a Westerly airflow.