When I last wrote, it was uncertain if overnight rain would be this far west – a 25% chance I thought. It now looks like it probably will be this far west.

Basically, thunderstorms are currently developing over the Bay Of Biscay, triggered by a cold front to the west which is pushing east. This same cold front will trigger further thundery downpours closer to the UK, say over the English Channel which will move north-east overnight, covering much of the SE quarter of England – but not all.

Still some uncertainty, as there always is in situations of developing thunderstorms – things are developing and moving this way, but Reading is roughly on the likely western-most boundary (though this boundary has moved west a bit on the models during the course of today) – which means we should get at least some overnight showers, potentially heavy/very heavy. And there is a small chance of thunder/lightning.

Timing from roughly 1/2am onwards – possibly still some rain in the morning too.

That is the most likely outcome anyway.

The main action in terms of torrential downpours, possible frequent lightning and localised flooding should be further east, over London, Essex, Kent, etc – it isn’t impossible that the main action is over Reading and similar central areas, but far more likely London, etc.

Nothing else has really changed – fresher but still very warm from tomorrow into the weekend, sunny spells, variable amounts of cloud and just very small chances of a stray shower.