A Status Yellow fog warning has been issued for 15 counties in the midlands.
Roscommon is one of those that will be affected from 10:00pm tonight.
The warning will expire at 10:00am tomorrow morning (Wendesday).
Meanwhile, a named storm is tracking towards Ireland.
Storm Eowyn has been named by the British Met Office, and could land on Thursday night.
Met Éireann Forecaster Andrew Doran Sherlock has been speaking to Midwest Radio’s Rian Bailey.
He gave the outlook on the arrival of Storm Eowyn, after explaining the fog forecast locally: