Amber “be prepared” warnings are in place for Wales and parts of England on Friday and Saturday.
In Scotland, yellow warnings of high winds and heavy rainfall are in effect with the storm front expected to batter the entire west coast as well as Edinburgh and the Lothians.
The Met Office said the storm would bring “delays to road, rail, air and ferry transport and for high-sided vehicles on exposed routes and bridges likely.”
The storm will hit the UK just hours before Princess Eugenie and Mr Brooksbank are expected to tie the knot in front of over 800 guests at the chapel in Windsor Castle at 11am on Friday October 12.
But the Met Office said on Wednesday the worst of the weather would be in western Scotland, Wales and the Lake District.
In a tweet, it added: “Friday’s weather system has been named as #StormCallum by @MetEireann. The strongest winds are likely in western Ireland though NW parts of the UK can expect severe gales. The main impacts for the UK will be from heavy rain across some western areas Friday & Saturday #weatheraware.”