Met Éireann has issued a status orange thunder warning for 16 counties.
The first warning is for all of Leinster as well as Cavan, Monaghan and Waterford.
The warning came into effect at 5am and is in place until 12pm.
A second orange thunder warning is in place for Tipperary, which came into effect at 6am and is in place until 10am.
Met Éireann said: "Thunderstorms will affect the eastern half of the country this morning with heavy downpours, the risk of hail and gusty winds.
"Temporary surface flooding is possible for a time, combined with the risk of hail will lead to hazardous driving conditions in some areas."