We don’t see any drivers around the northern Hemisphere to bring changes to the current circulation in the coming weeks. For the UK to see warmer and drier weather we need the jet stream to move back north by at least 10 to 15 degrees so the Atlantic low pressure development tracks are much further north. The current blocking pattern with below normal temperatures through the atmosphere over the NE Atlantic is expected to persist until the end of July, and most likely into August.
Influences that may alter the mid latitude circulation are most likely to be tropical activity related to increasing Pacific temperatures or El Nino. At the moment though the state is still neutral and may only become a weak El Nino. This will be too late to make much impact on our summer. Other features that can influence us later in the summer we be any Hurricane activity in the Atlantic and the tracks Hurricanes take, but again this will be near the end of summer for the UK and not possible to predict this far out.
In the shorter term there is yet more widespread rain to move across southern Britain on Thursday night and Friday with a high risk of flooding. Not quite as severe as recently, but with the ground saturated it won’t take much to raise rivers. During Friday Wales and the SW may receive another 25 to 45mm in 24-hours, which is a good half of the normal monthly July total.