Winds of up to 80mph could hit the county on Monday night, forecasters warned.
The Met Office issued a weather warning ahead of Storm Helene’s arrival, and said “injuries and danger to life from flying debris are possible.” The yellow warning, which means residents should be aware of possible disruption, is in place from 6pm on Monday until noon on Tuesday.
“Winds are likely to gust to 55-65 mph quite widely in the warning area, with possible gusts of 70-80 mph in exposure,” the forecaster said.
However, it accepted there “remains large uncertainty in Helene’s exact track”.
Large waves are expected on the coast, road, rail, air and ferry services may be affected, fallen trees may pose a hazard, and some roads and bridges may close.
Power cuts could also happen, and mobile phone coverage could drop out.