A rain warning has been issued for Roscommon and Leitrim.
The status yellow alert will run from 6pm on Saturday until midnight on Sunday.
Met Eireann says there will be heavy spells of rain and a risk of flooding.
Poor visibility and difficult driving conditions are also expected.
The rest of Connacht, and almost the entire western half of the country, will be under the same warning.
Meteorologist Aoife Kealy has been looking ahead to the weekend: