Ireland will bear the brunt of the storm, but gusts of 80mph are expected in parts of Scotland, with up to 10cm of rain falling.
The forecaster issued the status yellow weather advisory for Ireland.
Director Stephen Stewart said: "Even though power cuts are rare, during times of heavy rain and flooding they become more likely".
Shropshire is on the edge of the yellow warnings we have issued, with the most persistent and heaviest rain expected across Wales, north west England and south west England.
A storm that's been dubbed "Callum" will pass to northwest of the United Kingdom on Friday, bringing winds of up to 70mph and a prolonged downpour that will create hazardous conditions across the country.
"Winds will remain very strong on all coasts tomorrow Friday, with a second swathe of damaging winds possible across the southeast during late Friday morning and early afternoon", he added.
Met Éireann have issued three new weather warnings as Storm Callum nears Ireland.
The strongest winds are likely in western Ireland, although North Western parts of the United Kingdom can expect severe gales. "In addition, leaves and twigs, brought down by the wind, could block drains and culverts, increasing the likelihood of flooding".
It will come into effect on Thursday, October 11 at 11pm and last until 9am the following morning.
Coats on the south and west of the country are expected to be the worst affected by the storm, worth risks of heavy flooding and structural damage.
"Additionally there is a concern for storm surge, coastal flooding, and overtopping of waves around coasts, especially Atlantic coasts, due to the coinciding high spring tides".
In Galway, council crews are rolling out the city's aquadam ahead of potential high-tides of up to six metres.
Meanwhile NRW said its emergency response teams were checking flood defences, clearing gullies and ditches and installing temporary defences.
"It's not a major event in the east, we don't expect a major flooding event along the east coast", she told RTÉ Radio One's Today with Sean O'Rourke.