Met Office issues yellow thunderstorm warning for Northern Ireland

Heavy showers and thunderstorms could cause travel disruption and flash flooding across Northern Ireland today after the Met Office issued a yellow weather warning.

The warning takes effect at 12 noon today, Wednesday 19 August, and remains in place until 11.59pm tonight.

Some areas could receive up to 20mm of rain in an hour or less, while a few places may see as much as 30mm within two hours.

Heavy showers moving from west to east

According to the Met Office, a band of heavy showers is expected to spread across Northern Ireland from west to east during the late morning and early afternoon.

Further slow-moving heavy showers or thunderstorms are then forecast to develop later in the day.

The localised nature of thunderstorms means conditions could vary considerably over short distances. While some places may escape the most intense rainfall, others could experience torrential downpours over a relatively brief period.

Flash flooding and travel disruption possible

The Met Office said rainfall will be the primary hazard, with 15mm to 20mm likely to fall within an hour or less in the heaviest showers.

A few locations could receive between 25mm and 30mm over a couple of hours, creating the potential for surface water and flash flooding.

Road users may encounter difficult travelling conditions where intense rainfall causes standing water, spray and reduced visibility.

Drivers should allow additional time for journeys, reduce their speed during heavy rain and avoid attempting to pass through floodwater when its depth is unknown.

Hail and lightning also expected

Although heavy rain presents the main risk, the Met Office states hail and lightning are also likely in some places.

The warning remains effective until 11.59pm tonight, although its precise impacts will depend on where the slow-moving showers and thunderstorms develop.