Greater Manchester Braces for 15-Hour Thunderstorm Onslaught

The Met Office has issued a yellow weather warning for thunderstorms and heavy rain across Greater Manchester and surrounding areas, effective for 15 hours from 7pm on Wednesday, August 19, through to 10am on Thursday, August 20. This warning signals a return to classic British rainy weather following one of the driest summers on record, bringing an end to the recent heatwave.

Forecasters anticipate heavy showers and thunderstorms, which are likely to cause significant travel disruption and flash flooding. Rainfall could be substantial, with 15 to 20 mm falling in an hour in some areas, and totals of 30 to 50 mm possible over a six-hour period in certain locations. In addition to heavy rain, some showers are expected to be thundery, introducing hazards such as lightning and hail. These showers will ease from the northwest on Thursday morning.

The potential impacts of the storm include disrupted driving conditions and likely flooding of some homes and businesses. The Met Office also warns of possible rail disruption, short-term power supply issues, and damage to buildings or structures from lightning strikes. The warning extends across a broad region, encompassing all of Greater Manchester, Lancashire, Merseyside, and Cumbria, as well as most of Cheshire, Yorkshire, the North East, and North Wales, effectively stretching from Liverpool to Newcastle upon Tyne.

Specific rainfall forecasts for Greater Manchester indicate that heavy showers will develop this evening, becoming more frequent and widespread overnight. By 8pm, much of Greater Manchester will experience some rainfall. Stockport is predicted to see the highest amount, between 16 to over 32mm per hour, while Rochdale, Oldham, Bolton, Tameside, and Wigan could see 4-16mm across their boroughs. Rain is expected to move east by 9pm, but areas like Rochdale, Manchester, Tameside, Bolton, and Oldham may still see rainfall throughout the night. Heavy rain will return across Wigan, Bolton, Rochdale, and parts of Salford around 1am, with up to 16mm per hour, and intensify across much of Greater Manchester at 4am, particularly in Manchester and Rochdale, before easing off until 8am. Temperatures are set to drop to as low as 13 degrees overnight.

Furthermore, separate weather warnings for thunderstorms have been issued for Northern Ireland, running from midday until midnight today, and for part of north-east Scotland, including Aberdeen, from 2pm to 9pm.