Up to 40mm of rain could batter South East England within 12 hours as the Met Office issued a yellow weather warning covering London, Kent, Surrey, East Sussex, and parts of Essex from 3pm Friday until 3am Saturday.
Surface water flooding poses the biggest threat, with forecasters warning of difficult driving conditions, longer journey times, and transport disruption across the region. Between 20-30mm of rain is expected widely, though isolated downpours could push totals to 40mm in some spots.
The Met Office has urged residents to avoid non-essential travel during peak rainfall and warned of potential flooding to homes and businesses in vulnerable areas. Moderate winds of 10-15mph will accompany the downpours, with stronger gusts along exposed coastal stretches.
Residents should clear drains of leaves and debris where safe to do so and secure loose outdoor items. Despite the rainfall, temperatures will remain mild at 12-14°C throughout the warning period.
The weather will gradually clear from the west on Saturday morning, bringing brighter conditions by afternoon. However, saturated ground means Environment Agency flood alerts may persist even after the rain stops.
The rest of the UK, including Wales, Scotland, and Northern Ireland, will escape the worst conditions with settled but cloudy weather and temperatures between 10-14°C.
The Met Office advises checking local flood alerts via the Environment Agency website, avoiding floodwater, and keeping mobile phones charged in case of power cuts. Weather warnings will be updated as conditions develop.