Met Éireann has issued a Status Yellow Thunder warning for Counties Leitrim, Cavan, Roscommon, Sligo, Donegal, Longford, Louth, Meath and Monaghan this afternoon and evening.
They are also warning of heavy, thundery downpours with a risk of localised flooding.
Motorists are asked to remember that heavy rainfall can affect both visibility and road conditions. On wet roads, slow down and keep further back from the vehicle in front.
The warning is valid from 2pm until 9pm tonight, Tuesday, August 6.