A warning for Dublin, Louth, Wexford, Wicklow, Meath, Cork and Waterford is in place from 10pm on Thursday until 9am on Friday.
Before all that happens Thursday will be a day of heavy rain in many places.
There are two rain warnings from the Met office, one for Friday for Wales, also Cumbria into southern Scotland.
A zone of heavy rain associated with an intense weather system affecting western parts of the United Kingdom will become slow moving for a time, bringing prolonged rainfall and the potential for surface water flooding.
"The track of this storm is a bit further north than Storm Ali, so therefore Callum shouldn't be as damaging as Ali was in central parts of the country".
The Met Office has issued an amber weather alert from 6am on Friday to 6pm on Saturday for South Wales and is warning of hazardous conditions.More news: Red Sox Name Starters for Games 1 and 2 of ALCS
The forecaster issued the status yellow weather advisory for Ireland.
There is also a warning for rain in place for Cumbria from 12am to 23.59pm on Saturday (October 13). "You can check our website or call Floodline on 0345 988 1188 for any flood warnings that may be in place and keep an eye on weather reports and local news for details of any disruption in your area".
Gusts of up to 130 kilometres per hour are expected between 10 o'clock tomorrow night and 12 noon on Friday, with the worst of it overnight and early morning.
The AA is advising motorists to reduce speed accordingly to improve their ability to maintain control of their vehicle when driving through areas affected by Storm Callum.
Another bout of strong southerly winds will spread in during Friday night and last into Saturday but this won't be as bad as on Friday, just another windy day. On Saturday the rain could become even heavier.
"There are a number of locations on our network which have been susceptible to flooding during extreme weather and as such we are looking at possible amendments to services in partnership with Network Rail to reduce the impact of this weather".