This is the outlook for the next 4 weeks using the JMA issued from the Japanese Met Agency. This is not meant to be a forecast be a general outlook just using the JMA model. I have added the 3 images together and added a red line so you can see the UK. Blue colours are low pressure area and oranges high pressures.
Week 1 7th to 13th September.
A deep trough with low pressure in control. We will see above average rainfall and the temperature 2-3 degrees cooler than you would expect and windy at times.
Week 2 14th to 20th September.
High pressure looks like it will start to be in control bringing more settled conditions. It may be a few days into this period before we start to see some improvement. Rainfall will be around average and temperatures maybe just below average in a northerly airflow.
Week 3-4 21st September to 3th October.
High pressure will be in the Atlantic near to the UK. Overall fairly dry with temperature around average.